Laminate

Abstract

Disclosed is a laminate in which a substrate, a printed layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and a sealant layer are laminated in this order. The first adhesive layer and the second adhesive layer are cured products of a solventless adhesive. The intermediate layer includes a metal vapor-deposited layer in contact with the first adhesive layer. Between the substrate laminated by the first adhesive layer and the intermediate layer, the laminate strength at a peeling rate of 3 mm / min is 1.4 N / 15 mm or more.

Description

Laminate

[0001] This disclosure relates to laminates.

[0002] An example of a laminated packaging material used in packaging comprises a barrier substrate layer and a sealant layer. The barrier substrate layer comprises a barrier thermoplastic resin film and a thermoplastic resin film. An example of a barrier thermoplastic resin film is a biaxially oriented polyester film having a vapor-deposited thin film. In the barrier substrate layer, the barrier thermoplastic resin film and the thermoplastic resin film are bonded to each other by a bonding layer. The sealant layer is bonded to the barrier thermoplastic resin film by a bonding layer. An example of a lamination method for forming the bonding layer is a solvent-free lamination method (see, for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2008-44202

[0004] In recent years, with the increasing demand for environmentally friendly manufacturing methods, solvent-free lamination methods are being considered as an alternative to dry lamination, which uses adhesives containing organic solvents. However, when solvent-free lamination is applied to laminated packaging materials with vapor-deposited thin films, the same level of adhesion as in dry lamination cannot be achieved between the bonded layer (cured adhesive) and the vapor-deposited thin film, resulting in a new problem of reduced seal strength in the sealant layer. As mentioned above, solvent-free lamination cannot use organic solvents like dry lamination, so it is necessary to improve the adhesion between the cured adhesive and the vapor-deposited thin film using a method different from that used in dry lamination.

[0005] In a laminate for solving the above problems, a substrate, a printed layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and a sealant layer are laminated in the order described above. The first adhesive layer and the second adhesive layer are cured products of solvent-free adhesives. The intermediate layer includes a metal vapor deposition layer in contact with the first adhesive layer. Between the substrate laminated with the first adhesive layer and the intermediate layer, the laminate strength at a peeling speed of 3 mm / min is 1.4 N / 15 mm or more.

[0006] According to the above laminate, the laminate strength from the substrate containing the first adhesive layer to the intermediate layer is 1.4 N / 15 mm or more when the peeling speed is 3 mm / min, so the decrease in adhesion of the first adhesive layer to the vapor-deposited layer is suppressed. As a result, the decrease in the sealing strength of the sealant layer is suppressed.

[0007] In the laminate described above, the cured product of the adhesive may be a mixture of an aliphatic isocyanate and an aromatic isocyanate, and the glass transition temperature of the cured product may be 20°C or higher and 60°C or lower.

[0008] According to the above laminate, since the glass transition temperature of the cured material is 20°C or higher, the cured material has high elasticity, which suppresses a decrease in the adhesion of the first adhesive layer to the vapor-deposited layer. Furthermore, since the glass transition temperature of the cured material is 60°C or lower, the cohesive force of the adhesive is suppressed to become excessively high, thereby suppressing an excessive increase in the viscosity of the adhesive. As a result, a decrease in the coating suitability of the adhesive is suppressed.

[0009] In the laminate described above, the cured product of the adhesive may be a mixture of an aliphatic isocyanate and an aromatic isocyanate, and the glass transition temperature of the cured product may be 36°C or higher and 45°C or lower.

[0010] According to the above laminate, since the glass transition temperature of the cured material is 36°C or higher, the cured material has high elasticity, which suppresses a decrease in the adhesion of the first adhesive layer to the vapor-deposited layer. Furthermore, since the glass transition temperature of the cured material is 45°C or lower, the cohesive force of the adhesive is suppressed to become excessively high, thereby suppressing an excessive increase in the viscosity of the adhesive. As a result, a decrease in the coating suitability of the adhesive is suppressed.

[0011] In the above laminate, the main component of the adhesive may be a polyol containing polyester, and the curing agent of the adhesive may also contain an aliphatic isocyanate.

[0012] With the above laminate, the crosslinking rate of the adhesive is lower and the reactivity with water is also lower compared to when the curing agent is an aromatic isocyanate. Therefore, the generation of gases such as carbon dioxide due to the reaction between the adhesive and water is suppressed. As a result, the formation of air bubbles in the cured product of the first adhesive is also suppressed, and thus deterioration of the appearance is also suppressed.

[0013] In the above laminate, the substrate may be a nylon film.

[0014] According to the above laminate, the nylon film, being rigid to the sealant layer, does not stretch easily. Therefore, when measuring the seal strength, the stretch of the substrate cannot keep up with the stretch of the sealant layer, resulting in delamination easily occurring at the interface between the first adhesive layer and the intermediate layer. For this reason, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0015] In the laminate described above, the sealant layer may be an unstretched film mainly composed of polyethylene.

[0016] According to the above laminate, the sealant layer, being softer than the substrate, is easily stretched. Therefore, when measuring the seal strength, the stretching of the substrate cannot keep up with the stretching of the sealant layer, resulting in delamination easily occurring at the interface between the first adhesive layer and the intermediate layer. For this reason, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination rate of 3 mm / min can be significantly obtained.

[0017] In the laminate described above, the intermediate layer may include a polyethylene terephthalate film, the vapor-deposited layer may be laminated on the polyethylene terephthalate film, and the polyethylene terephthalate film may be in contact with the second adhesive layer.

[0018] In the above laminate, the second adhesive layer is sandwiched between the sealant layer and the resin film. Therefore, the adhesion from the sealant layer including the second adhesive layer to the intermediate layer is higher than the adhesion from the substrate including the first adhesive layer to the intermediate layer. Consequently, when measuring the seal strength, the polyethylene terephthalate film attempts to stretch in accordance with the elongation of the sealant layer while maintaining adhesion to the sealant layer by the second adhesive layer. This makes delamination more likely at the interface between the vapor-deposited layer included in the intermediate layer and the first adhesive layer. Therefore, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0019] In the above laminate, the vapor-deposited layer may be formed from aluminum. According to the above laminate, the laminate can have high gas barrier properties.

[0020] In the laminate described above, the sum of the thickness of the first adhesive layer and the thickness of the printed layer may be 2.0 μm or more and 5.5 μm or less, and the thickness of the second adhesive layer may be 1.5 μm or more and 3.0 μm or less.

[0021] In the laminate described above, the curing agent of the adhesive may be an aliphatic isocyanate, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer may be 0.01 or more and less than 1.0.

[0022] In the laminate described above, the curing agent of the adhesive may be a mixture of an aliphatic isocyanate and an aromatic isocyanate, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer may be 0.2 or more and less than 1.0.

[0023] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive is an aliphatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 60°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.01 or more and less than 1.0.

[0024] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 45°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer may be 0.2 or more and less than 1.0.

[0025] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive is an aliphatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 60°C or less, the intermediate layer contains a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer may be formed from aluminum.

[0026] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the glass transition temperature of the cured product is 36°C or higher and 45°C or lower, the intermediate layer contains a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer may be formed from aluminum.

[0027] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive contains an aliphatic isocyanate, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less, the substrate is a nylon film, the sealant layer is an unstretched film mainly composed of polyethylene, the intermediate layer contains a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer may be formed from aluminum.

[0028] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive is an aliphatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 60°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less, the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.01 or more and less than 1.0, the substrate is a nylon film, the sealant layer is an unstretched film mainly composed of polyethylene, the intermediate layer includes a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer may be formed from aluminum.

[0029] In the laminate described above, the main component of the adhesive is a polyol containing polyester, the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 45°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less, the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.2 or more and less than 1.0, the substrate is a nylon film, the sealant layer is an unstretched film mainly composed of polyethylene, the intermediate layer includes a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer may be formed from aluminum.

[0030] The laminate of this disclosure makes it possible to suppress a decrease in seal strength.

[0031] Figure 1 is a cross-sectional view showing the structure of one embodiment of the laminate. Figure 2 is a schematic diagram illustrating a method for measuring laminate strength. Figure 3 is a schematic diagram illustrating a method for measuring seal strength. Figure 4 is a plan view showing the structure of a standing pouch, which is an example of a packaging bag formed using the laminate. Figure 5 is a table showing the evaluation results for each example and comparative example. Figure 6 is a table showing the evaluation results for each example and comparative example. Figure 7 is a scatter plot showing the relationship between seal strength and laminate strength when the peeling speed is 3 mm / min for each example and comparative example. Figure 8 is a scatter plot showing the relationship between seal strength and laminate strength when the peeling speed is 300 mm / min for each example and comparative example. Figure 9 is a scatter plot showing the relationship between glass transition temperature (Tg) and seal strength for each example and comparative example.

[0032] An embodiment of the laminate will be described with reference to Figures 1 to 9. [Laminate] The laminate will be described with reference to Figures 1 to 3. As shown in Figure 1, the laminate 10 of the present disclosure comprises a substrate 11, a printed layer 12, a first adhesive layer 13, an intermediate layer 14, a second adhesive layer 15, and a sealant layer 16. In the laminate 10, the substrate 11, the printed layer 12, the first adhesive layer 13, the intermediate layer 14, the second adhesive layer 15, and the sealant layer 16 are laminated in the order described above. The first adhesive layer 13 and the second adhesive layer 15 are cured products of solvent-free adhesives. The intermediate layer 14 includes a metal vapor-deposited layer 14A in contact with the first adhesive layer 13. The intermediate layer 14 further includes a support layer 14B that supports the vapor-deposited layer 14A. The substrate 11 and the support layer 14B are harder and less stretchable than the sealant layer 16.

[0033] The base material 11 is a film made of synthetic resin. The base material 11 may be an unoriented film, a uniaxially oriented film, or a biaxially oriented film. For example, the base material 11 may be polyethylene terephthalate film, polypropylene film, polystyrene film, nylon film, polycarbonate film, polyacrylonitrile film, polyimide film, etc. The thickness of the base material 11 may be, for example, 4 μm or more and 40 μm or less.

[0034] The printed layer 12 is a layer formed by printing using ink. The printed layer 12 may be formed on the entire surface of the substrate 11 on which the printed layer 12 is formed, or it may be formed on only a part of the surface on which the printed layer 12 is formed.

[0035] The printed layer 12 is formed from at least one type of ink, which includes a colored ink. The colored ink includes a pigment and a binder resin. Therefore, the printed layer contains at least a pigment and a binder resin. Note that the composition of the ink used as a material for printing and the ink contained in the printed layer may differ due to the influence of layer-forming processes such as drying and curing, but in this disclosure, for convenience, these are collectively referred to as ink.

[0036] The color ink may be, for example, white ink, red ink, yellow ink, blue ink, black ink, etc. The type of pigment contained in the color ink may be appropriately determined according to the color to be expressed. For example, the pigment may be an inorganic pigment or an organic pigment. The inorganic pigment may be, for example, titanium oxide, carbon black, that is, ink pigment, etc. The organic pigment may be, for example, azo pigment, phthalocyanine pigment, dioxazine pigment, quinacridone pigment, isoindolinone pigment, dye lake pigment, etc. The ink may contain a plurality of types of pigments.

[0037] The binder resin contained in the color ink may be, for example, alkyd resin, phenolic resin, maleic resin, natural resin, hydrocarbon resin, polyvinyl chloride resin, polyacetic resin, polystyrene resin, polyvinyl butyral resin, acrylic resin, methacrylic resin, polyamide resin, polyester resin, polyurethane resin, epoxy resin, urea resin, melamine resin, nitrocellulose, ethyl cellulose, etc. The color ink may contain only one type of binder resin or two or more types.

[0038] The ink for forming the printing layer 12 may be aqueous ink or oily ink. From the perspective of environmental protection, it is preferable that the ink is aqueous ink. From the perspective of enhancing productivity and suppressing appearance defects more, it is preferable that the ink is oily ink.

[0039] The ink may contain a solvent. The solvent may be a solvent used for printing ink. The ink may contain one or more of additives such as plasticizer, stabilizer, antioxidant, light stabilizer, ultraviolet absorber, curing agent, crosslinking agent, lubricant, antistatic agent, filler, etc. as required.

[0040] The printing layer 12 may be a layer for displaying patterns such as characters, figures, symbols, patterns, etc. There is no particular limitation on the type of pattern expressed by the printing layer 12. According to the type of pattern expressed by the printing layer 12, the type of ink used for forming the printing layer 12 may be appropriately determined.

[0041] From the perspective of obtaining the reproducibility of the pattern, the thickness of the printing layer 12 is preferably 0.1 μm or more. Also, from the perspective of reducing the step difference between the portion where the printing layer 12 is not formed and the portion where the printing layer 12 is formed, it is preferably 4 μm or less. By reducing the step difference, for example, when laminating after applying an adhesive to the intermediate layer 14, the followability of the adhesive to the printing layer 12 can be easily obtained, and thus uniform adhesion can be achieved. Also, when laminating after applying an adhesive to the base material 11 including the printing layer 12, the variation in the thickness of the adhesive layer becomes small.

[0042] The printing method may be, for example, offset printing, gravure printing, flexographic printing, silk screen printing, inkjet printing, electrophotographic method, etc. For the purpose of enhancing the adhesion of the printing layer 12 to the base material 11, corona treatment or ozone treatment may be performed on the surface of the base material 11 where the printing layer 12 is to be formed before forming the printing layer 12.

[0043] The first adhesive layer 13 and the second adhesive layer 15 are cured products of a solventless adhesive. Since the solventless adhesive does not contain volatile organic compounds (VOCs), the environmental load is low. The adhesive for forming the first adhesive layer 13 and the second adhesive layer 15 may be a two-component curable polyurethane-based adhesive composed of a main agent and a curing agent. The main agent may be, for example, polyester polyol, polyether polyol, acrylic polyol, etc. The main agent is preferably polyester polyol.

[0044] Polyester polyols are, for example, esterification products of polycarboxylic acids, dialkyl esters of polycarboxylic acids, or mixtures thereof, with glycol-based compounds. Polycarboxylic acids may include, for example, succinic acid, glutaric acid, isophthalic acid, terephthalic acid, adipic acid, pimelic acid, corticic acid, azelaic acid, sebatic acid, dodecanedioic acid, and dimer acids. Glycol-based solvents may include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.

[0045] The curing agent may be, for example, an aromatic isocyanate compound containing two or more functional groups, an aliphatic isocyanate compound containing two or more functional groups, or a mixture of an aromatic isocyanate compound and an aliphatic isocyanate.

[0046] Aliphatic polyisocyanates may include, for example, tetramethylene diisocyanate, isopropyl diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, and derivatives thereof. Derivatives may include, for example, isocyanurates.

[0047] Aromatic polyisocyanates may include, for example, tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and derivatives thereof. Derivatives may include, for example, isocyanurates.

[0048] Two-component curing adhesives harden when the hydroxyl groups of the main component react with the isocyanate groups of the curing agent by heating or other means. The sum of the thickness of the first adhesive layer 13 and the thickness of the printed layer 12 may be, for example, 2.0 μm or more and 5.5 μm or less. Preferably, the sum of the thickness of the first adhesive layer 13 and the thickness of the printed layer 12 is 2.0 μm or more and 5.0 μm or less, and more preferably 2.0 μm or more and 4.5 μm or less. The thickness of the second adhesive layer 15 may be, for example, 1.5 μm or more and 3.0 μm or less.

[0049] When the curing agent of the adhesive is an aliphatic isocyanate, the ratio of the thickness of the first adhesive layer 13 to the sum of the thicknesses of the first adhesive layer 13 and the printing layer 12 may be 0.01 or more and less than 1.0. Preferably, the ratio of the thickness of the first adhesive layer 13 to the sum of the thicknesses of the first adhesive layer 13 and the printing layer 12 is 0.1 or more and 0.8 or less, and more preferably 0.15 or more and 0.6 or less. When the curing agent of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the ratio of the thickness of the first adhesive layer 13 to the sum of the thicknesses of the first adhesive layer 13 and the printing layer 12 may be 0.2 or more and less than 1.0. Preferably, the ratio of the thickness of the first adhesive layer 13 to the sum of the thicknesses of the first adhesive layer 13 and the printing layer 12 is 0.25 or more and 0.8 or less, and more preferably 0.3 or more and 0.6 or less.

[0050] The intermediate layer 14 comprises a vapor-deposited layer 14A and a support layer 14B that supports the vapor-deposited layer 14A. The vapor-deposited layer 14A is formed from a metal. The material forming the vapor-deposited layer 14A may be, for example, aluminum, chromium, nickel, copper, zinc, silver, indium, platinum, gold, or an alloy containing two or more of these. Preferably, the vapor-deposited layer 14A is formed from aluminum. This can improve the gas barrier properties of the laminate 10. The thickness of the vapor-deposited layer 14A may be, for example, 40 nm or more and 50 nm or less. The method for forming the vapor-deposited layer 14A on the support layer 14B may be physical vapor deposition (PVD), chemical vapor deposition (CVD), or a liquid-phase method. Physical vapor deposition may be vacuum deposition, sputtering, or ion plating. Chemical vapor deposition may be plasma CVD. The liquid-phase method may be, for example, electroplating.

[0051] The support layer 14B is a film made of synthetic resin. The support layer 14B may be an unoriented film, a uniaxially oriented film, or a biaxially oriented film. For example, the support layer 14B may be polyethylene terephthalate film, polypropylene film, polystyrene film, nylon film, polycarbonate film, polyacrylonitrile film, polyimide film, etc. The thickness of the support layer 14B may be, for example, 10 μm or more and 40 μm or less.

[0052] The sealant layer 16 is a film made of synthetic resin. The sealant layer 16 may be a film made of polyolefin resin. Examples of polyolefin resins include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EAA), ionomer, polypropylene, etc. The sealant layer 16 may be a single layer or a multi-layer. If the sealant layer 16 is a multi-layer, it may include a layer formed from a first resin and a layer formed from a second resin different from the first resin. The thickness of the sealant layer may be, for example, 50 μm or more and 200 μm or less.

[0053] In this embodiment, the intermediate layer 14 is composed of a vapor-deposited layer 14A and a support layer 14B. The first adhesive layer 13 adheres the printed layer 12 and the portion of the substrate 11 not covered by the printed layer 12 to the vapor-deposited layer 14A. The second adhesive layer 15 adheres the sealant layer 16 to the support layer 14B.

[0054] In the laminate 10, it is sufficient that the vapor-deposited layer 14A of the intermediate layer 14 is in contact with the first adhesive layer 13. Therefore, the laminate 10 may include other layers, for example, between the substrate 11 and the printed layer 12, between the printed layer 12 and the first adhesive layer 13, between the vapor-deposited layer 14A and the support layer 14B, between the support layer 14B and the second adhesive layer 15, and between the second adhesive layer 15 and the sealant layer 16. If the laminate 10 includes other layers, the materials constituting the other layers should be selected so as not to reduce the adhesion between layers and, consequently, the seal strength.

[0055] Figure 2 schematically shows a method for measuring the laminate strength in the laminate 10. As shown in Figure 2, the laminate strength in the laminate 10 between the base material 11 and the intermediate layer 14, that is, the laminate strength in the layer structure consisting of the base material 11, the printed layer 12, the first adhesive layer 13, and the intermediate layer 14 in this embodiment, is measured as follows. First, at the edge of the first layer, which is one of the layers from the base material 11 to the intermediate layer 14, the first layer and the second layer adjacent to the first layer are separated. In the example shown in Figure 2, at the edge of the first adhesive layer 13 and the vapor-deposited layer 14A, the first adhesive layer 13 is separated from the vapor-deposited layer 14A.

[0056] Next, the laminate 10 is peeled in a T-shape by peeling the first layer away from the second layer so that the edge of the first layer separates from the edge of the second layer. In the example shown in Figure 2, the laminate 10 is peeled in a T-shape by peeling the first adhesive layer 13 away from the vapor-deposited layer 14A so that the edge of the first adhesive layer 13 separates from the edge of the vapor-deposited layer 14A. For measuring the laminate strength, the peeling speed, which is the speed at which the second layer is peeled from the first layer, is set to a predetermined speed.

[0057] The laminate 10 of this disclosure satisfies the following condition 1: (Condition 1) Between the substrate 11 laminated by the first adhesive layer 13 and the intermediate layer 14, the lamination strength at a peeling speed of 3 mm / min is 1.4 N / 15 mm or more.

[0058] Figure 3 schematically shows the state of the laminate 10 when its seal strength is measured. Figure 3 also schematically shows the phenomenon that occurs in the laminate 10 when the adhesion strength between the first adhesive layer 13 and the vapor-deposited layer 14A is insufficient.

[0059] As shown in Figure 3, when measuring the seal strength of the laminate 10, first, a test piece T cut from the laminate 10 is folded in half so that the first part of the sealant layer 16 contained in the test piece T and a second part different from the first part are in contact. Next, a portion of the folded test piece having a predetermined width from the fold line FL is heat-sealed to form a seal portion TS. Then, the first part T1 and the second part T2 of the test piece T, which sandwich the seal portion TS, are pulled apart in a T-shape.

[0060] Of the layers included in the laminate 10, the substrate 11 is harder than the sealant layer 16. Therefore, when measuring the seal strength, the sealant layer 16 deforms significantly, i.e., it stretches easily, while the substrate 11 does not deform easily, i.e., it does not stretch easily. As a result, the portion of the first adhesive layer 13 that includes the surface in contact with the vapor-deposited layer 14A experiences a large stress due to the deformation of the sealant layer 16, while the portion of the first adhesive layer 13 that includes the surface facing the printed layer 12 experiences a small stress due to the deformation of the substrate 11.

[0061] Furthermore, the adhesion strength of the first adhesive layer 13 to the vapor-deposited layer 14A, i.e., the lamination strength by the first adhesive layer 13, is lower than the external force required to stretch the substrate 11. Therefore, when measuring the heat seal strength, delamination occurs at the interface between the first adhesive layer 13 and the vapor-deposited layer 14A in both the first portion T1 and the second portion T2 before the substrate 11 stretches. This results in triangular delamination, where a gap is created between the layer structure including the first adhesive layer 13 from the substrate 11 and the layer including the intermediate layer 14 and the sealant layer 16. In addition, when measuring the seal strength, the curvature at the bent portion increases along the direction from the sealant layer 16 toward the substrate 11. This also makes the first adhesive layer 13 more prone to stress concentration than the second adhesive layer 15, and as a result, triangular delamination is more likely to occur between the first adhesive layer 13 and the intermediate layer 14.

[0062] When triangular delamination occurs in the first portion T1 and the second portion T2, the vertical external force acting on the first portion T1 and the second portion T2 acts on the layer structure including only the intermediate layer 14 and the sealant layer 16. In contrast, when triangular delamination does not occur, the vertical external force acting on the first portion T1 and the second portion T2 acts on the layer structure including the entirety of the substrate 11 and the sealant layer 16. As a result, in a test specimen T in which triangular delamination has occurred, a portion of the test specimen T will fracture even with a lower force applied compared to a test specimen T in which triangular delamination has not occurred. Specifically, fracture occurs in at least one of the first portion T1 and the second portion T2 contained in the test specimen T in the layer structure including only the intermediate layer 14 and the sealant layer 16. This reduces the sealing strength of the test specimen T.

[0063] In packaging bags using a laminate 10 with low seal strength, triangular delamination is likely to occur, and as a result, the sealant layer 16, which has low rupture strength, is likely to be included in the layer structure consisting only of the intermediate layer 14 and the sealant layer 16. Therefore, rupture of the layer structure including the intermediate layer 14 and the sealant layer 16 is likely to occur, and as a result, the contents of the packaging bag are likely to leak.

[0064] In this regard, according to the laminate 10 of this disclosure, the laminate strength between the substrate 11 including the first adhesive layer 13 and the intermediate layer 14 is 1.4 N / 15 mm or more when the peeling speed is 3 mm / min, so that a decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A is suppressed. As a result, triangular delamination at the interface between the first adhesive layer 13 and the intermediate layer 14 is suppressed when measuring the seal strength. Consequently, a decrease in the seal strength of the sealant layer 16 is suppressed.

[0065] For the first adhesive layer 13 to have high adhesion to the vapor-deposited layer 14A to the extent that triangular delamination does not occur, the first adhesive layer 13 must have a certain degree of viscoelasticity. If elasticity is dominant in the first adhesive layer 13, and as a result the first adhesive layer 13 is too hard, then when an external force is applied to the first adhesive layer 13, stress concentrates between the first adhesive layer 13 and the vapor-deposited layer 14A. As a result, delamination occurs near the interface between the first adhesive layer 13 and the vapor-deposited layer 14A. Also, if the first adhesive layer 13 is too hard, stress concentrates between the printed layer 12 and the first adhesive layer 13. As a result, delamination occurs near the interface between the printed layer 12 and the first adhesive layer 13. On the other hand, if viscosity is dominant in the first adhesive layer 13, and as a result the first adhesive layer 13 is too fluid, the cohesive force of the first adhesive layer 13 is low, and as a result the first adhesive layer 13 is prone to cohesive failure.

[0066] When measuring the laminate strength of a layered structure including the base material 11 to the intermediate layer 14, if the peeling speed is set to 300 mm / min, it is considered that the viscoelasticity of the first adhesive layer 13 cannot be properly evaluated for the following reasons. That is, when the peeling speed is high, the viscous resistance generated in the first adhesive layer 13 causes the first adhesive layer 13 to behave harder than it actually is, and as a result, even if the elasticity of the first adhesive layer 13 is low, a laminate strength value can be obtained that indicates that the first adhesive layer 13 has high adhesion to the vapor-deposited layer 14A. However, when the seal strength is measured for a test piece T including the first adhesive layer 13, a value that does not correlate with the laminate strength may be obtained.

[0067] In this regard, as with the laminate 10 of this disclosure, by measuring the laminate strength at a peel strength of 3 mm / min, the first adhesive layer 13 is peeled off from the vapor-deposited layer 14A at a low speed. As a result, viscous resistance is less likely to occur in the first adhesive layer 13, and the influence of viscous resistance on the value of the laminate strength can be eliminated as much as possible. Therefore, it is possible to measure the laminate strength corresponding to the viscoelasticity of the first adhesive layer 13, and as a result, a laminate strength value correlated with the seal strength can be obtained.

[0068] The laminate 10 may satisfy at least one of the following conditions 2 to 6 in addition to condition 1. That is, the laminate 10 may satisfy only one of conditions 2-1 to 6, or it may satisfy two or more of conditions 2 to 6.

[0069] (Condition 2-1) The curing agent of the adhesive is an aliphatic isocyanate, and the glass transition temperature of the cured product is 20°C or higher and 60°C or lower. (Condition 2-2) The cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, and the glass transition temperature of the cured product is 36°C or higher and 45°C or lower. (Condition 3) The main component of the adhesive is a polyol containing polyester, and the curing agent of the adhesive contains an aliphatic isocyanate.

[0070] (Condition 4) The base material 11 is a nylon film. (Condition 5) The sealant layer 16 is an unstretched film mainly composed of polyethylene. (Condition 6) The intermediate layer 14 contains a polyethylene terephthalate (PET) film, the vapor-deposited layer 14A is laminated on the PET film, and the PET film is in contact with the second adhesive layer 15.

[0071] When the laminate 10 satisfies condition 2-1, the glass transition temperature of the cured material is 20°C or higher, which gives the cured material high elasticity, thus suppressing a decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A. Furthermore, since the glass transition temperature of the cured material is 60°C or lower, the cohesive force of the adhesive is suppressed to become excessively high, thereby suppressing an excessive increase in the viscosity of the adhesive. As a result, a decrease in the coating suitability of the adhesive is suppressed. The glass transition temperature is preferably 25°C to 55°C, and more preferably 28°C to 50°C.

[0072] When the laminate 10 satisfies condition 2-2, the glass transition temperature of the cured material is 36°C or higher, which gives the cured material high elasticity, thus suppressing a decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A. Furthermore, since the glass transition temperature of the cured material is 45°C or lower, the cohesive force of the adhesive is suppressed to become excessively high, thereby suppressing an excessive increase in the viscosity of the adhesive. As a result, a decrease in the coating suitability of the adhesive is suppressed.

[0073] When the laminate 10 satisfies condition 3, the crosslinking rate of the adhesive is lower and the reactivity with water is lower compared to when the curing agent is an aromatic isocyanate. Therefore, the generation of gases such as carbon dioxide due to the reaction between the adhesive and water is suppressed. This also suppresses the formation of air bubbles in the cured product of the first adhesive layer 13, thus suppressing deterioration of the appearance.

[0074] If bubbles form at the interface between the first adhesive layer 13 and the vapor-deposited layer 14A, the area in contact between the first adhesive layer 13 and the vapor-deposited layer 14A will decrease by the area of ​​the bubbles. This will reduce the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A. However, if the laminate 10 satisfies condition 3, the formation of bubbles is suppressed, and therefore the decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A is also suppressed.

[0075] When the laminate 10 satisfies condition 4, the rigid nylon film does not stretch easily relative to the sealant layer 16. Therefore, when measuring the seal strength, the elongation of the substrate 11 cannot keep up with the elongation of the sealant layer 16, and as a result, delamination is likely to occur at the interface between the first adhesive layer 13 and the intermediate layer 14. For this reason, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0076] When the laminate 10 satisfies condition 5, the sealant layer 16, which is softer than the substrate 11, is easily stretched. Therefore, when measuring the seal strength, the stretching of the substrate 11 cannot keep up with the stretching of the sealant layer 16, and as a result, delamination is likely to occur at the interface between the first adhesive layer 13 and the intermediate layer 14. For this reason, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0077] If the laminate 10 satisfies condition 6, the second adhesive layer 15 is sandwiched between the sealant layer 16 and the resin film, so the adhesion between the sealant layer 16 including the second adhesive layer 15 and the intermediate layer 14 is higher than the adhesion between the substrate 11 including the first adhesive layer 13 and the intermediate layer 14.

[0078] In other words, the affinity between the first adhesive layer 13 and the vapor-deposited layer 14A in the intermediate layer 14 is low, while the second adhesive layer 15 has a higher affinity for resin layers, or its affinity for adjacent resin layers is increased by surface treatment such as corona treatment. Furthermore, in the printed layer 12 that is in contact with the first adhesive layer 13, the adhesion between the first adhesive layer 13 and the printed layer 12 is increased due to the anchoring effect caused by the irregularities of the printed layer 12 and the diffusion of adhesive into the printed layer 12.

[0079] On the other hand, when measuring seal strength, the stress during delamination is absorbed by the stretching of the sealant layer 16, thereby relieving the stress. In contrast, the first adhesive layer 13 is sandwiched between layers made of a material that is less stretchable than the sealant layer 16, so the stress relief that occurs with the sealant layer 16 does not occur. As a result, the stress during delamination tends to concentrate at the interface between the first adhesive layer 13 and the substrate 11 or intermediate layer 14, and in the first adhesive layer 13 itself. Consequently, delamination is likely to occur in areas with low adhesion, such as near the interface between the vapor-deposited layer 14A and the first adhesive layer 13, and cohesive failure of the first adhesive layer 13 is likely to occur.

[0080] Thus, when measuring the seal strength, the PET film attempts to stretch in accordance with the elongation of the sealant layer 16 while maintaining adhesion to the sealant layer 16 by the second adhesive layer 15. As a result, delamination is more likely to occur at the interface between the vapor-deposited layer 14A included in the intermediate layer 14 and the first adhesive layer 13. Therefore, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0081] [Packaging Bag] The packaging bag will be described with reference to Figure 4. The packaging bag of this disclosure is formed by manufacturing a packaging material including the laminate 10 described above. In the following, a standing pouch, which is an example of the packaging bag described, will be explained, but the packaging bag is not limited to a standing pouch, and may be a three-sided seal pouch or a four-sided seal pouch, for example.

[0082] Figure 4 shows the planar structure of the standing pouch 20. As shown in Figure 4, the standing pouch 20 is a self-standing pouch. The standing pouch 20 comprises a surface film 21F, a back film 21R, and a bottom film 21B. The standing pouch 20 has a bag-like shape in which the surface film 21F, the back film 21R, and the bottom film 21B are heat-sealed, with the bottom film 21B sandwiched between the surface film 21F and the back film 21R to form a gusset portion.

[0083] The surface film 21F, the back film 21R, and the bottom film 21B are each composed of the laminate 10 described above. Therefore, each film 21F, 21R, and 21B includes a substrate 11, a printing layer 12, a first adhesive layer 13, an intermediate layer 14, a second adhesive layer 15, and a sealant layer 16. The surface film 21F and the back film 21R are facing each other so that the sealant layers 16 contained in each film 21F and 21R are in contact. The bottom film 21B is sandwiched between the films 21F and 21R such that a part of the sealant layer 16 of the bottom film 21B is in contact with a part of the sealant layer 16 of the surface film 21F, and another part of the sealant layer 16 of the bottom film 21R is in contact with another part of the sealant layer 16 of the back film 21R.

[0084] The standing pouch 20 includes a side seal portion 20S1, a bottom seal portion 20S2, and a spout seal portion 20S3. In the side seal portion 20S1, the surface film 21F is heat-sealed to the back film 21R. In the side seal portion 20S1, the side edge of the surface film 21F is heat-sealed to the side edge of the back film 21R. In the bottom seal portion 20S2, the lower edge of the surface film 21F and the lower edge of the back film 21R are heat-sealed to the bottom film 21B. The standing pouch 20 has an opening 20A at its top. The contents are filled into the storage space of the standing pouch 20 through the opening 20A. In the standing pouch 20, after the contents are filled, the back film 21R is heat-sealed to the surface film 21F at the opening 20A.

[0085] In the spout seal portion 20S3, one corner of the upper edge of the surface film 21F is heat-sealed to one corner of the upper edge of the back film 21R. This forms a spout portion 20B in the standing pouch 20. The spout portion 20B includes the spout seal portion 20S3 and an unsealed portion surrounded by the spout seal portion 20S3. The standing pouch 20 is equipped with an opening portion 20C. The opening portion 20C is located on both the surface film 21F and the back film 21R, and each opening portion 20C is located within the spout portion 20B. In each film 21F, 21R, each end of the opening portion 20C is located on the spout seal portion 20S3, and the central portion sandwiched between the two ends is located on the unsealed portion. Each opening portion 20C is composed only of the sealant layer 16 provided on each film 21F, 21R.

[0086] The standing pouch 20, together with the contents contained within it, constitutes the packaging. The contents may be, for example, toiletries. The toiletries may be in liquid form. The liquid may contain a solvent and a solute, or a dispersion medium and a dispersed phase. In this embodiment, the toiletries may be detergents, laundry aids, deodorants, body care products, or hair care products. The detergents may be household detergents, kitchen detergents, or laundry detergents. The laundry aids may be laundry aids for clothing, such as liquid fabric softeners or liquid starches. The body care products may be, for example, body shampoos, hand creams, or body creams. The hair care products may be, for example, shampoos, rinses, conditioners, hair creams, or hair waxes.

[0087] When using the standing pouch 20, the user breaks the dispensing section 20B at the opening section 20C, thereby forming a spout that connects to the contents of the standing pouch 20. The user then dispenses the contents of the standing pouch 20 from the spout to the outside of the standing pouch 20.

[0088] With the standing pouch 20, each film 21F, 21R, and 21B made up of the laminate 10 is resistant to tearing, so the standing pouch 20 is also resistant to tearing.

[0089] [Examples] Examples and comparative examples will be described with reference to Figures 5 to 9. As an adhesive for forming the first adhesive layer 13 and the second adhesive layer 15, a solvent-free, two-component urethane adhesive was prepared, consisting of one of the curing agents described below and one of the main components described below. [Curing agents] ・Isocyanate A Aliphatic isocyanate NCO content: 20% by mass ・Isocyanate B Mixture of aliphatic isocyanate and aromatic isocyanate NCO content: 20% by mass ・Isocyanate C Aromatic isocyanate NCO content: 22% by mass ・Isocyanate D Mixture of aliphatic isocyanate and aromatic isocyanate NCO content: 21% by mass

[0090] [Main component] • Polyol A: Ester-based polyol, OH value: 148 mg KOH / g • Polyol B: Ester-based polyol, OH value: 254 mg KOH / g • Polyol C: Ester-based polyol, OH value: 178 mg KOH / g • Polyol D: Ether-based polyol, OH value: 140 mg KOH / g • Polyol E: Ester-based polyol, OH value: 140 mg KOH / g

[0091] [Example 1] A nylon (NY) film with a thickness of 15 μm was prepared as the substrate 11. A printed layer 12 having a pattern covering a part of the first surface was formed on the substrate 11.

[0092] As the intermediate layer 14, a PET film with a vapor-deposited layer was prepared, consisting of a PET film with a thickness of 12 μm, which is the support layer 14B, and an aluminum vapor-deposited layer with a thickness of 50 nm, which is the vapor-deposited layer 14A. As the sealant layer 16, an unstretched linear low-density polyethylene (LLDPE) film with a thickness of 100 μm was prepared.

[0093] As an adhesive for forming the first adhesive layer 13 and the second adhesive layer 15, a solvent-free, two-component urethane adhesive was prepared, consisting of isocyanate A as a curing agent and polyol A as a main component. The adhesive was prepared by mixing 100 parts by mass of curing agent and 90 parts by mass of main component in terms of solid content ratio.

[0094] Adhesive was applied to the printed layer 12 and the portion of the substrate 11 exposed from the printed layer 12. Subsequently, the substrate 11 and the vapor-deposited layer 14A were laminated so that the adhesive was sandwiched between the printed layer 12 and the vapor-deposited layer 14A. This formed a first adhesive layer 13 between the printed layer 12 and the vapor-deposited layer 14A. At this time, the amount of adhesive applied to the printed layer 12 was 2.9 g / m². ２ 3.2g / m or more ２ The following settings are used, and the amount of the first adhesive layer 13 applied is 2.0 g / m². ２The following settings were applied. Next, adhesive was applied to the side of the intermediate layer 14 opposite to the vapor-deposited layer 14A, and then the sealant layer 16 and the support layer 14B were laminated so that adhesive was sandwiched between the sealant layer 16 and the support layer 14B. At this time, the lamination temperature was set to 55°C and the lamination pressure was set to 0.3 Pa. After lamination, aging was performed at 40°C. This obtained the laminate 10 of Example 1.

[0095] [Example 2] In Example 1, the amount of printed layer 12 applied was 5 g / m². ２ 6g / m or more ２ The laminate 10 of Example 2 was obtained by the same method as in Example 1, except for the following changes.

[0096] [Reference Example 1] The laminate 10 of Reference Example 1 was obtained by the same method as in Example 1, except that the printed layer 12 was not formed.

[0097] [Example 3] In Example 1, the amount of the main component was changed to 70 parts by mass, and the coating amount of the printed layer 12 was changed to 2.5 g / m². ２ Except for the change made, the laminate 10 of Example 3 was obtained by the same method as in Example 1.

[0098] [Example 4] The laminate 10 of Example 4 was obtained by the same method as in Example 3, except that the amount of the main component was changed to 50 parts by mass.

[0099] [Example 5] The laminate 10 of Example 5 was obtained by the same method as in Example 3, except that the amount of the main component was changed to 110 parts by mass.

[0100] [Example 6] The laminate 10 of Example 6 was obtained by the same method as in Example 3, except that the amount of the main component was changed to 130 parts by mass.

[0101] [Example 7] In Example 1, the amount of the first adhesive layer 13 applied was 1.5 g / m². ２ The amount of coating on the printing layer 12 was changed to 2.5 g / m². ２ The laminate 10 of Example 8 was obtained by the same method as in Example 1, except that it was changed to [specific component].

[0102] [Example 8] The laminate 10 of Example 8 was obtained in the same manner as in Example 7, except that the amount of the main agent was changed to 70 parts by mass.

[0103] [Example 9] The laminate 10 of Example 9 was obtained in the same manner as in Example 7, except that the amount of the main agent was changed to 110 parts by mass.

[0104] [Example 10] The laminate 10 of Example 10 was obtained in the same manner as in Example 1, except that the main agent was changed to ester polyol B and the amount of the main agent was changed to 50 parts by mass.

[0105] [Example 11] The laminate 10 of Example 11 was obtained in the same manner as in Example 2, except that the main agent was changed to polyol B and 100 parts by mass of the curing agent and 50 parts by mass of the main agent were used.

[0106] [Example 12] The laminate 10 of Example 12 was obtained in the same manner as in Example 1, except that the curing agent was changed to isocyanate B, the main agent was changed to polyol C, and the amount of the main agent was changed to 75 parts by mass.

[0107] [Example 13] The laminate 10 of Example 13 was obtained in the same manner as in Example 12, except that the amount of the curing agent was changed to 100 parts by mass.

[0108] [Comparative Example 1] The laminate 10 of Comparative Example 1 was obtained in the same manner as in Example 12, except that the coating amount of the printing layer 12 was changed to 5 g / m[[ID=​​​​​​​​​​​​​​

[0111] [Reference Example 3] The laminate 10 of Reference Example 3 was obtained by the same method as in Example 13, except that the printed layer 12 was not formed.

[0112] [Example 14] In Comparative Example 1, the amount of the first adhesive layer 13 applied was 2.5 g / m². ２ Except for the change made, the laminate 10 of Example 14 was obtained by the same method as in Comparative Example 1.

[0113] [Example 15] In Comparative Example 2, the amount of the first adhesive layer 13 applied was 2.5 g / m². ２ Except for the change made, the laminate 10 of Example 15 was obtained by the same method as in Comparative Example 2.

[0114] [Comparative Example 3] The laminate 10 of Comparative Example 3 was obtained by the same method as in Example 13, except that the amount of curing agent was changed to 80 parts by mass.

[0115] [Comparative Example 4] A laminate 10 of Comparative Example 4 was obtained by the same method as in Example 1, except that the curing agent was changed to isocyanate C, the main component was changed to polyol D, and the amount of the main component was changed to 70 parts by mass.

[0116] [Comparative Example 5] In Example 1, the curing agent was changed to isocyanate D, the main component was changed to polyol E, and the amount of the main component was changed to 100 parts by mass. Otherwise, the laminate 10 of Comparative Example 5 was obtained by the same method as in Example 1.

[0117] [Evaluation Method] [Glass Transition Temperature (Tg)] Dynamic mechanical analysis (DMA) was performed according to the method compliant with JIS K 7244-1:1998 "Plastics - Test methods for dynamic mechanical properties - Part 1: General rules". A thermomechanical analyzer (DMA7100, manufactured by Hitachi High-Tech Science Corporation) was used as the dynamic viscoelasticity measuring device.

[0118] Using the adhesives for forming the adhesive layers 13 and 15 of the laminate 10 in each example and comparative example, a single film, which is a cured adhesive with a thickness of 30 μm to 35 μm, was formed. Next, the loss tangent tanδ (loss modulus E'' / storage modulus E') in the tensile mode was measured by dynamic viscoelasticity measurement of the thin film. From the measured value of the loss tangent tanδ, the temperature at which the maximum value of the loss tangent tanδ was obtained was read. This temperature was set as the glass transition temperature (Tg) of the cured adhesive. The tensile frequency of the cured material was set to 10 Hz when measuring the loss tangent tanδ.

[0119] [Laminate Strength] The laminate strength of the laminate 10 was measured according to the method conforming to JIS K 6854-3:1999 "Adhesives - Test methods for peel adhesion strength - Part 3: T-type peel". A tensile testing machine (AUTOGRAPH AGS-X 5kN, manufactured by Shimadzu Corporation) was used to measure the laminate strength. When measuring the laminate strength, first, strip-shaped test pieces with a width of 15 mm were cut from the laminate 10 of each example and each comparative example. At this time, six test pieces were cut from each laminate 10.

[0120] After setting the test specimen in the tensile testing machine, the specimen was peeled while being pulled in a T-shape, and the test force obtained by allowing the elongation during tensile testing to a maximum of approximately 80 mm was defined as the laminate strength (N / 15 mm). In cases where the test force acting on the test specimen was approximately constant, the average value of the test force was set as the laminate strength for that specimen. Furthermore, if the test specimen fractured immediately after the start of measurement, and the test force had a maximum peak due to the fracture, the maximum value was set as the laminate strength for that specimen.

[0121] For each laminate 10, the laminate strength was measured on three test pieces when the peeling speed of the tensile testing machine was set to 3 mm / min, and the laminate strength was also measured on three test pieces when the peeling speed of the tensile testing machine was set to 300 mm / min. The average value of the measurement results at each peeling speed was then calculated. The calculated average value was set as the laminate strength at 3 mm / min and the laminate strength at 300 mm / min for each laminate 10.

[0122] [Seal Strength] The seal strength of the laminate 10 was measured according to the method conforming to JIS Z 0238:1998 "Test Methods for Heat-Sealable Flexible Packaging Bags and Semi-Rigid Containers". A tensile testing machine (AUTOGRAPH AGS-X 5kN, manufactured by Shimadzu Corporation) was used to measure the seal strength.

[0123] To measure the seal strength, first, sheets with a width of 50 mm and a length of 150 mm were cut from the laminate 10 of each example and comparative example. Next, each sheet was folded in half so that the first part of the sealant layer 16 and a second part different from the first part were in contact. Subsequently, the folded sheet was heat-sealed 1 cm from the fold line FL to form a sealed portion TS. At this time, the heat sealing temperature was set to 150°C, the pressure to 0.2 MPa, and the heating time to 1 second. Subsequently, three test pieces T with a width of 15 mm were prepared from the sheet.

[0124] The first end of the test specimen T in the longitudinal direction was attached to the first chuck of the tensile testing machine, and the second end in the longitudinal direction was attached to the second chuck of the tensile testing machine. The test specimen T was then pulled in a T-shape until it broke, and the maximum load applied to the test specimen T until it broke was measured as the seal strength (N / 15 mm). The peeling speed was set to 300 mm / min.

[0125] Furthermore, the measured seal strength was evaluated at the following two levels: ○: The seal strength was 85 N / 15 mm, indicating high seal strength. ×: The seal strength was less than 85 N / 15 mm, indicating insufficient seal strength.

[0126] [Thickness] Test specimens were cut from the laminate 10 of each example and comparative example. The entire test specimen was then embedded in an ultraviolet-curable resin, and subsequently, the embedded test specimen was cut using a microtome to expose the cross-section for observation. The sum of the thickness of the first adhesive layer 13 and the thickness of the printed layer 12, and the thickness of the first adhesive layer 13 were measured in the image obtained by observing the cross-section with a scanning electron microscope (JSM-7001F, JEOL Ltd.). The magnification during observation was set to 10,000x.

[0127] During this process, the sum of the thicknesses of the first adhesive layer 13 and the printed layer 12, and the thickness of the first adhesive layer 13 itself, were measured at three locations. The average values ​​for the sum of the thicknesses of the first adhesive layer 13 and the printed layer 12, and the thickness of the first adhesive layer 13, were set to the values ​​for the laminate 10 of each example and comparative example. The locations where the thickness was measured were those where no deformation had occurred due to cutting of the test piece, and where there was no gouging or sagging of the first adhesive layer 13.

[0128] [Evaluation Results] The evaluation results for the laminates of each example and each comparative example are shown in Figures 5 to 9.

[0129] As shown in Figure 5, the glass transition temperature in the cured adhesive was found to be 31.8°C in Examples 1 and 2 and Reference Example 1, 45.5°C in Examples 3 and 8, 60.4°C in Example 4, and 27.3°C in Examples 5 and 9. The glass transition temperature was found to be 27.3°C in Examples 5 and 9, 20.1°C in Example 6, 31.8°C in Example 7, 43.8°C in Examples 10 and 11, and 34.7°C in Examples 12 and 14, Comparative Example 1, and Reference Example 2. The glass transition temperature was found to be 22.2°C in Examples 13 and 15, Comparative Example 2, and Reference Example 3, 14.7°C in Comparative Example 3, -4.0°C in Comparative Example 4, and 16.5°C in Comparative Example 5.

[0130] The loss tangent tanδ in the cured adhesive was found to be 0.78 in Examples 1, 2, 7 and Reference Example 1, 0.71 in Examples 3, 4, and 8, 0.82 in Example 5, and 0.88 in Example 6. The tanδ was found to be 0.82 in Example 9, 1.01 in Examples 10 and 11, 0.75 in Examples 12 and 14, Comparative Example 1 and Reference Example 2, and 0.83 in Examples 13 and 15, Comparative Example 2 and Reference Example 3. The tanδ was found to be 0.97 in Comparative Example 3, 0.48 in Comparative Example 4, and 0.70 in Comparative Example 5.

[0131] As shown in Figure 6, when the peeling speed was set to 3 mm / min, the laminate strength was found to be 1.41 N / 15 mm in Example 1, 1.42 N / 15 mm in Example 2, and 2.18 N / 15 mm in Reference Example 1. The laminate strength was found to be 2.36 N / mm in Example 3, 1.89 N / 15 mm in Example 4, 2.25 N / 15 mm in Examples 5 and 10, 2.27 N / 15 mm in Example 6, and 1.77 N / 15 mm in Example 7. The laminate strength was found to be 1.95 N / 15 mm in Example 8, 1.87 N / 15 mm in Example 9, 2.72 N / 15 mm in Example 11, 1.63 N / 15 mm in Example 12, and 2.29 N / 15 mm in Example 13. The laminate strength was found to be 1.20 N / 15 mm in Comparative Example 1, 1.36 N / 15 mm in Comparative Example 2, 2.61 N / 15 mm in Reference Example 2, 2.36 N / 15 mm in Reference Example 3, and 1.73 N / 15 mm in Example 14. The laminate strength was found to be 1.93 N / 15 mm in Example 15, 1.15 N / 15 mm in Comparative Example 3, 1.37 N / mm in Comparative Example 4, and 1.33 N / 15 mm in Comparative Example 5.

[0132] When the peeling speed was set to 300 mm / min, the laminate strength was found to be 2.66 N / 15 mm in Example 1, 3.32 N / 15 mm in Example 2, 1.55 N / 15 mm in Reference Example 1, and 1.56 N / 15 mm in Example 3. The laminate strength was found to be 1.19 N / 15 mm in Example 4, 2.63 N / 15 mm in Example 5, 3.58 N / 15 mm in Example 6, 2.08 N / 15 mm in Example 7, and 1.96 N / 15 mm in Example 8. The laminate strength was found to be 2.58 N / 15 mm in Example 9, 3.61 N / 15 mm in Example 10, 4.16 N / 15 mm in Example 11, 2.87 N / 15 mm in Example 12, and 3.15 N / 15 mm in Example 13. The laminate strength was found to be 2.25 N / 15 mm in Comparative Example 1, 2.77 N / 15 mm in Comparative Example 2, 1.37 N / 15 mm in Reference Example 2, 3.59 N / 15 mm in Reference Example 3, and 3.14 N / 15 mm in Example 14. The laminate strength was found to be 3.69 N / 15 mm in Example 15, 2.29 N / 15 mm in Comparative Example 3, 2.20 N / 15 mm in Comparative Example 4, and 2.40 N / 15 mm in Comparative Example 5.

[0133] The seal strength was found to be 89 N / 15 mm in Example 1, 87 N / 15 mm in Examples 2 and 12, 88 N / 15 mm in Reference Example 1, 96 N / 15 mm in Examples 3 and 4, and 94 N / 15 mm in Examples 5 and 7. It was found to be 93 N / 15 mm in Examples 6 and 11, 97 N / 15 mm in Examples 8 and 14, 90 N / 15 mm in Example 9, 92 N / 15 mm in Examples 10, 15 and Reference Example 3, and 91 N / 15 mm in Example 13. The seal strength was found to be 65 N / 15 mm in Comparative Examples 1 and 2, 86 N / 15 mm in Reference Example 2, 97 N / 15 mm in Example 14, 58 N / 15 mm in Comparative Example 3, 78 N / 15 mm in Comparative Example 4, and 64 N / 15 mm in Comparative Example 2.

[0134] The relationship between laminate strength and seal strength when the peel strength is set to 3 mm / min is shown in Figure 7, and the relationship between laminate strength and seal strength when the peel strength is set to 300 mm / min is shown in Figure 8.

[0135] Specifically, when the peel strength was set to 3 mm / min, it was observed that the seal strength increased sharply with increasing laminate strength in the range of less than 1.4 N / 15 mm. Furthermore, when the peel strength was set to 3 mm / min, it was observed that while the seal strength increased with increasing laminate strength in the range of 1.4 N / 15 mm or more, it remained within the predetermined range of 85 N / 15 mm or more.

[0136] Therefore, when the peel strength is set to 3 mm / min, the resulting laminate strength has a high correlation with the seal strength, and it can be said that it is possible to set a threshold for laminate strength that achieves high seal strength.

[0137] On the other hand, when the peel strength was set to 300 mm / min, it was found that there was little correlation between the laminate strength and the seal strength in the range of 2.5 N / 15 mm or less, making it difficult to determine the threshold laminate strength at which a seal strength above a certain level could be obtained.

[0138] The relationship between seal strength and glass transition temperature is shown in Figure 9. As shown in Figure 9, when the curing agent for forming the first adhesive layer 13 contains only aliphatic isocyanates and does not contain aromatic isocyanates, it was found that a glass transition temperature of 20°C or higher resulted in a seal strength of 85 N / 15 mm or higher.

[0139] As described above, according to one embodiment of the laminate, the following effects can be obtained: (1) Since the laminate 10 satisfies condition 1, a decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A is suppressed. As a result, a decrease in the heat seal strength of the sealant layer 16 is suppressed.

[0140] (2-1) When the glass transition temperature of the cured product is 20°C or higher, the cured product has high elasticity, which suppresses a decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A. Also, when the glass transition temperature of the cured product is 60°C or lower, the cohesive force of the adhesive is suppressed to become excessively high, thereby suppressing an excessive increase in the viscosity of the adhesive. As a result, a decrease in the coating suitability of the adhesive is suppressed. (2-2) When the glass transition temperature of the cured product is 36°C or higher, the cured product has high elasticity, which suppresses a decrease in the adhesion of the first adhesive layer 13 to the vapor-deposited layer 14A. Also, when the glass transition temperature of the cured product is 45°C or lower, the cohesive force of the adhesive is suppressed to become excessively high, thereby suppressing an excessive increase in the viscosity of the adhesive. As a result, a decrease in the coating suitability of the adhesive is suppressed.

[0141] (3) When condition 3 is met, the crosslinking rate of the adhesive is lower and the reactivity with water is lower compared to when the curing agent is an aromatic isocyanate. As a result, the generation of gases such as carbon dioxide due to the reaction between the adhesive and water is suppressed. This also suppresses the formation of air bubbles in the cured product of the first adhesive layer 13, thus suppressing deterioration of the appearance.

[0142] (4) When condition 4 is met, the rigid nylon film does not stretch easily relative to the sealant layer 16. Therefore, when the heat seal strength is measured, the elongation of the substrate 11 cannot keep up with the elongation of the sealant layer 16, and as a result, delamination is likely to occur at the interface between the first adhesive layer 13 and the intermediate layer 14. For this reason, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0143] (5) When condition 5 is met, the sealant layer 16, which is softer than the substrate 11, is easily stretched. Therefore, when the heat seal strength is measured, the stretch of the substrate 11 cannot keep up with the stretch of the sealant layer 16, and as a result, delamination is likely to occur at the interface between the first adhesive layer 13 and the intermediate layer 14. For this reason, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0144] (6) When condition 6 is met, the second adhesive layer 15 is sandwiched between the sealant layer 16 and the resin film, so the adhesion between the sealant layer 16 including the second adhesive layer 15 and the intermediate layer 14 is higher than the adhesion between the substrate 11 including the first adhesive layer 13 and the intermediate layer 14. Therefore, when the seal strength is measured, the polyethylene terephthalate film tries to stretch in accordance with the elongation of the sealant layer 16 while maintaining adhesion to the sealant layer 16 by the second adhesive layer 15, so delamination is more likely to occur at the interface between the vapor-deposited layer 14A included in the intermediate layer 14 and the first adhesive layer 13. Therefore, the effect of having a laminate strength of 1.4 N / 15 mm or more at a delamination speed of 3 mm / min can be significantly obtained.

[0145] 10...Laminate 11...Substrate 12...Printed layer 13...First adhesive layer 14...Intermediate layer 14A...Vaporized layer 14B...Support layer 15...Second adhesive layer 16...Sealant layer 20...Standing pouch

Claims

1. A laminate comprising a substrate, a printed layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and a sealant layer, laminated in the order described above, wherein the first adhesive layer and the second adhesive layer are cured products of a solvent-free adhesive, the intermediate layer includes a metal vapor-deposited layer in contact with the first adhesive layer, and the laminate strength between the substrate laminated by the first adhesive layer and the intermediate layer is 1.4 N / 15 mm or more at a peeling rate of 3 mm / min.

2. The laminate according to claim 1, wherein the curing agent of the adhesive is an aliphatic isocyanate, and the glass transition temperature of the cured product is 20°C or more and 60°C or less.

3. The laminate according to claim 1, wherein the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, and the glass transition temperature of the cured product is 36°C or higher and 45°C or lower.

4. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, and the curing agent of the adhesive contains an aliphatic isocyanate.

5. The laminate according to any one of claims 1 to 4, wherein the base material is a nylon film.

6. The laminate according to any one of claims 1 to 4, wherein the sealant layer is an unstretched film mainly composed of polyethylene.

7. The laminate according to any one of claims 1 to 4, wherein the intermediate layer includes a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, and the polyethylene terephthalate film is in contact with the second adhesive layer.

8. The laminate according to any one of claims 1 to 4, wherein the vapor-deposited layer is formed from aluminum.

9. The laminate according to any one of claims 1 to 4, wherein the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, and the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less.

10. The laminate according to claim 1, wherein the curing agent of the adhesive is an aliphatic isocyanate, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.01 or more and less than 1.

0.

11. The laminate according to claim 1, wherein the curing agent of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.2 or more and less than 1.

0.

12. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive is an aliphatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 60°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.01 or more and less than 1.

0.

13. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 45°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, and the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.2 or more and less than 1.

0.

14. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive is an aliphatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 60°C or less, the intermediate layer comprises a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer is formed from aluminum.

15. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the glass transition temperature of the cured product is 36°C or higher and 45°C or lower, the intermediate layer comprises a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer is formed from aluminum.

16. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive contains an aliphatic isocyanate, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less, the substrate is a nylon film, the sealant layer is an unstretched film mainly composed of polyethylene, the intermediate layer contains a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer is formed from aluminum.

17. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the curing agent of the adhesive is an aliphatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 60°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less, the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.01 or more and less than 1.0, the substrate is a nylon film, the sealant layer is an unstretched film mainly composed of polyethylene, the intermediate layer includes a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer is formed from aluminum.

18. The laminate according to claim 1, wherein the main component of the adhesive is a polyol containing polyester, the cured product of the adhesive is a mixture of an aliphatic isocyanate and an aromatic isocyanate, the glass transition temperature of the cured product is 20°C or more and 45°C or less, the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 2.0 μm or more and 5.5 μm or less, the thickness of the second adhesive layer is 1.5 μm or more and 3.0 μm or less, the ratio of the thickness of the first adhesive layer to the sum of the thickness of the first adhesive layer and the thickness of the printed layer is 0.2 or more and less than 1.0, the substrate is a nylon film, the sealant layer is an unstretched film mainly composed of polyethylene, the intermediate layer includes a polyethylene terephthalate film, the vapor-deposited layer is laminated on the polyethylene terephthalate film, the polyethylene terephthalate film is in contact with the second adhesive layer, and the vapor-deposited layer is formed from aluminum.

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