Packaging material and pouch

Abstract

To enhance the dropping strength and oxygen absorption performance of a packaging material.SOLUTION: There is provided a packaging material which comprises at least a first stretched plastic film, a first adhesive layer, a second stretched plastic film, a second adhesive layer, a third stretched plastic film, a third adhesive layer, and a sealant film in this order. The packaging material has a barrier layer located between the first stretched plastic film and the first adhesive layer, between the first adhesive layer and the second stretched plastic film, or between the second stretched plastic film and the second adhesive layer. The first adhesive layer or the second adhesive layer contains an oxygen-absorbing adhesive composition. The sealant film contains a block polypropylene and a polyethylene.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present disclosure relate to packaging materials and pouches. [Background technology]

[0002] There are many pouches on the market that are made of plastic packaging materials and filled and sealed with cooked or semi-cooked liquid, viscous material, or a mixture of liquid and solid. In the pouch, the non-sealed portion where the packaging materials are not joined constitutes the storage portion in which the contents are stored. Also, the sealed portion where the packaging materials are joined seals the storage portion. The contents are, for example, cooked foods such as curry or soup. The contents are heated in a microwave oven or the like while contained in the pouch.

[0003] When the contents contained in a sealed pouch are heated in a microwave oven, the moisture contained in the contents evaporates as the contents are heated, and the pressure in the storage section increases. If the pressure in the storage section of the pouch increases, the pouch may burst, scattering the contents and soiling the microwave oven. In consideration of such a problem, for example, Patent Document 1 proposes providing the pouch with a steam release mechanism that automatically connects the storage section to the outside when the pressure in the storage section increases, and releases steam in the storage section to the outside. In Patent Document 1, the steam release mechanism has an intermediate seal section located between the upper side seal section and the lower side seal section of the pouch, and a non-seal section that is isolated from the storage section by the intermediate seal section and extends to reach the side edge of the pouch. If the pressure in the storage section increases, the intermediate seal section peels off, and the storage section and the non-seal section communicate with each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-101154 Summary of the Invention [Problem to be solved by the invention]

[0005] The pouch is required to have drop strength, i.e., to prevent the pouch from bursting when it receives an impact due to being dropped, and to prevent the contents from deteriorating due to oxidation.

[0006] An object of the present disclosure is to provide a packaging material that can effectively solve such problems. [Means for solving the problem]

[0007] The embodiments of the present disclosure relate to the following [1] to

[17] . [1] A packaging material comprising, in this order, at least a first stretched plastic film, a first adhesive layer, a second stretched plastic film, a second adhesive layer, a third stretched plastic film, a third adhesive layer, and a sealant film, the packaging material comprises a barrier layer located between the first stretched plastic film and the first adhesive layer, between the first adhesive layer and the second stretched plastic film, or between the second stretched plastic film and the second adhesive layer; At least one of the first adhesive layer, the second adhesive layer, and the third adhesive layer that is located on the inner side of the barrier layer contains an oxygen-absorbing adhesive composition, The sealant film comprises block polypropylene and polyethylene.

[0008] [2] In the packaging material described in [1], the third adhesive layer may not contain an oxygen-absorbing adhesive composition.

[0009] [3] The packaging material described in [1] or [2] may further comprise a printed layer located between the first stretched plastic film and the first adhesive layer, the first adhesive layer may not contain an oxygen-absorbing adhesive composition, and the second adhesive layer may contain an oxygen-absorbing adhesive composition.

[0010] [4] In the packaging material according to any one of [1] to [3], the barrier layer may be located between the first stretched plastic film and the first adhesive layer.

[0011] [5] In the packaging material described in [4], the barrier layer may include a transparent vapor deposition layer.

[0012] [6] In the packaging material described in any one of [1] to [3], the barrier layer may be located between the first adhesive layer and the second stretched plastic film, or between the second stretched plastic film and the second adhesive layer.

[0013] [7] In the packaging material described in [6], the barrier layer may include a transparent vapor deposition layer.

[0014] [8] In the packaging material according to any one of [1] to [7], the content of the block polypropylene in the sealant film may be 70% by mass or more and 85% by mass or less.

[0015] [9] In the packaging material described in [8], the sealant film may be a non-oriented polypropylene film having a tensile elongation of 1000% or more in the machine direction and a tensile elongation of 1100% or more in the perpendicular direction, and a thickness of 50 μm or more.

[0016]

[10] In the packaging material according to any one of [1] to [7], the content of the block polypropylene in the sealant film may be 80% by mass or more and 96% by mass or less.

[0017]

[11] In the packaging material described in

[10] , the sealant film may be an unstretched polypropylene film having a tensile elongation of less than 1000% in the machine direction and a tensile elongation of less than 1100% in the perpendicular direction, and having a thickness of 60 μm or more.

[0018]

[12] In the packaging material according to any one of [1] to

[11] , the oxygen-absorbing adhesive composition may contain at least an oxygen-absorbing compound and an oxidation-promoting catalyst. The oxygen-absorbing compound may contain one or more unsaturated five-membered rings. Any bond between the five carbon atoms constituting the unsaturated five-membered ring may be a carbon-carbon double bond. The unsaturated five-membered ring may have a monovalent and / or divalent or higher electron-donating organic group 1 bonded thereto. When the unsaturated five-membered ring is one, the unsaturated five-membered ring or the organic group 1 may contain a functional group having active hydrogen or a group in which the active hydrogen of the functional group having active hydrogen is substituted with a monovalent organic group 2. When the unsaturated five-membered ring is two or more, the unsaturated five-membered rings may be bonded to each other via a divalent or higher organic group 2 that substitutes the active hydrogen of the active hydrogen group on each of the five-membered rings or the organic group 1.

[0019]

[13] In the packaging material according to

[12] , the oxidation-promoting catalyst may be a peroxide or a compound containing a cation consisting of a transition metal.

[0020]

[14] In the packaging material described in any one of [1] to

[13] , the content of the transition metal constituting the oxidation-promoting catalyst of the oxygen-absorbing adhesive composition in the first adhesive layer or the second adhesive layer may be 20 ppm or more.

[0021]

[15] In the packaging material according to any one of [1] to

[14] , the first stretched plastic film, the second stretched plastic film and the third stretched plastic film may all be stretched polyester films.

[0022]

[16] A pouch in which a storage section for storing contents is defined between a front film and a back film, a steam vent mechanism that discharges steam from the storage section to the outside when the pressure in the storage section increases; A pouch, wherein the front film and the back film are made of the packaging material according to any one of [1] to

[15] .

[0023]

[17] The pouch described in

[16] comprises a first side seal portion located on a first side of the pouch and joining an inner surface of the front film and an inner surface of the back film, a second side seal portion located on a second side opposite the first side of the pouch in a first direction and defining the containing portion between the first side seal portion and the second side seal portion, and a first non-seal portion located toward an upper portion of the pouch and isolated from the containing portion by the first side seal portion, the first non-seal portion extending to reach a first side edge of the first side of the pouch. the first side sealed portion may include an upper sealed portion extending along the first side from the first non-sealed portion toward an upper portion of the pouch, a lower sealed portion extending along the first side from the first non-sealed portion toward a lower portion of the pouch, and an intermediate sealed portion having one end connected to the upper sealed portion and the other end connected to the lower sealed portion and positioned between the containing portion and the first non-sealed portion, and the first non-sealed portion and the intermediate sealed portion may constitute the steam release mechanism. Effect of the Invention

[0024] According to the embodiment of the present disclosure, the drop strength and oxygen absorption performance of the packaging material can be improved. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a cross-sectional view showing an example of a packaging material according to the present embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of a packaging material according to the present embodiment. [Diagram 3] FIG. 2 is a cross-sectional view showing an example of a packaging material according to the present embodiment. [Figure 4] FIG. 2 is a front view showing an example of a pouch according to the present embodiment. [Diagram 5] FIG. 2 is a front view showing the pouch containing the contents. [Figure 6] FIG. 13 is a front view showing a modified example of the pouch. [Figure 7] FIG. 13 is a front view showing a modified example of the pouch. [Figure 8] FIG. 13 is a front view showing a modified example of the pouch. [Figure 9] FIG. 2 is a diagram showing the configurations and evaluation results of pouches in Examples 1 to 3 and Comparative Examples 1 to 4. [Figure 10] 1 is a graph showing the analysis results of the second adhesive layer of Example 1 by ICP-OES. [Figure 11] 1 is a graph showing the analysis results of the second adhesive layer of Comparative Example 1 by ICP-OES. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The embodiments will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0027] In addition, terms used in this specification that specify shapes, geometric conditions, and the extent thereof, such as "parallel," "orthogonal," and "same," as well as values ​​of length and angle, are not bound by strict meanings and are interpreted to include a range within which similar functions can be expected.

[0028] In this specification, when two or more upper limit candidates and two or more lower limit candidates are given for a certain parameter, the numerical range of the parameter may be constructed by combining any one of the upper limit candidates and any one of the lower limit candidates. For example, consider a case where "parameter B may be, for example, A1 or more and may be A2 or more. Parameter B may be, for example, A3 or less and may be A4 or less." In this case, the numerical range of parameter B may be A1 or more and A3 or less, A1 or more and A4 or less, A2 or more and A3 or less, or A2 or more and A4 or less.

[0029] <Packaging materials> The packaging material according to the present embodiment comprises at least a first stretched plastic film, a first adhesive layer, a second stretched plastic film, a second adhesive layer, a third stretched plastic film, a third adhesive layer, and a sealant film, in this order. The packaging material further comprises a barrier layer located outside the second adhesive layer in the thickness direction. The "outside in the thickness direction" refers to the side closer to the outer surface of the packaging material. Conversely, the "inside in the thickness direction" refers to the side closer to the inner surface of the packaging material. The packaging material may further comprise a printing layer located between the first stretched plastic film and the first adhesive layer.

[0030] The packaging material according to the present embodiment will be described with reference to the drawings. An example of the packaging material according to the present embodiment is shown in Figs.

[0031] 1 includes, in this order from the outer surface 50y toward the inner surface 50x, a first stretched plastic film 51, a barrier layer 64, a printed layer 61, a first adhesive layer 56, a second stretched plastic film 52, a second adhesive layer 57, a third stretched plastic film 53, a third adhesive layer 58, and a sealant film 55. In a pouch formed from the packaging material 50, the inner surface 50x faces the storage portion.

[0032] As shown in FIG. 1, the outer surface 51y of the first stretched plastic film 51 may constitute the outer surface 50y of the packaging material 50. The barrier layer 64 may be located on the inner surface 51x of the first stretched plastic film 51. The barrier layer 64 may include a transparent deposition layer 62 and a gas barrier coating film 63. The transparent deposition layer 62 may be located on the inner surface 51x of the first stretched plastic film 51. The gas barrier coating film 63 is located on the transparent deposition layer 62. The printing layer 61 is located between the gas barrier coating film 63 and the first adhesive layer 56. The printing layer 61 may be in contact with the first adhesive layer 56. The printing layer 61 may be in contact with the gas barrier coating film 63.

[0033] The outer surface 52y of the second stretched plastic film 52 may be in contact with the first adhesive layer 56. The inner surface 52x of the second stretched plastic film 52 may be in contact with the second adhesive layer 57. The outer surface 53y of the third stretched plastic film 53 may be in contact with the second adhesive layer 57. The inner surface 53x of the third stretched plastic film 53 may be in contact with the third adhesive layer 58. The outer surface 55y of the sealant film 55 may be in contact with the third adhesive layer 58. The inner surface 55x of the sealant film 55 may constitute the inner surface 50x of the packaging material 50.

[0034] The packaging material 50 shown in Fig. 2 differs from the packaging material 50 shown in Fig. 1 in terms of the arrangement of the printed layer 61 and the barrier layer 64. The arrangement of the other layers in the packaging material 50 shown in Fig. 2 is the same as that in the packaging material 50 shown in Fig. 1.

[0035] As shown in FIG. 2, the barrier layer 64 may be located on the outer surface 52y of the second stretched plastic film 52. The barrier layer 64 may include a transparent deposition layer 62 and a gas barrier coating film 63. The transparent deposition layer 62 may be located on the outer surface 52y of the second stretched plastic film 52. The gas barrier coating film 63 is located on the transparent deposition layer 62. The gas barrier coating film 63 may be in contact with the first adhesive layer 56. The printing layer 61 may be located on the inner surface 51x of the first stretched plastic film 51. The printing layer 61 may be in contact with the inner surface 51x of the first stretched plastic film 51. The printing layer 61 may be in contact with the first adhesive layer 56.

[0036] The packaging material 50 shown in Figure 3 differs from the packaging material 50 shown in Figure 2 in terms of the arrangement of the barrier layer 64. The arrangement of the other layers in the packaging material 50 shown in Figure 3 is the same as in the packaging material 50 shown in Figure 2.

[0037] 3, the barrier layer 64 may be located on the inner surface 52x of the second stretched plastic film 52. The barrier layer 64 may include a transparent vapor deposition layer 62 and a gas barrier coating film 63. The transparent vapor deposition layer 62 may be located on the inner surface 52x of the second stretched plastic film 52. The gas barrier coating film 63 is located on the transparent vapor deposition layer 62. The gas barrier coating film 63 may be in contact with the second adhesive layer 57.

[0038] The films and layers that make up packaging material 50 are described below.

[0039] [Stretched plastic film] The first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53 are all made of stretched plastic films. A stretched plastic film is a film made of plastic and stretched in a predetermined direction. The stretched plastic film may be a biaxially stretched plastic film stretched in two predetermined directions. The stretching ratio of the stretched plastic film is, for example, 1.05 times or more.

[0040] The biaxially stretched plastic film has a machine direction and a perpendicular direction. The machine direction is the direction in which the film is transported when the film is formed, and is called MD (Machine Direction). The perpendicular direction is the direction perpendicular to the machine direction, and is called TD (Transverse Direction). The sealant film 55 also has a machine direction and a perpendicular direction. When the pouch 10 described later is manufactured using the packaging material 50, the first direction is the machine direction, and the second direction is the perpendicular direction.

[0041] The stretching ratio of the biaxially stretched plastic film in the machine direction and the perpendicular direction is, for example, 1.05 times or more.

[0042] The tensile strength TS2T of the biaxially stretched plastic film in the perpendicular direction is equal to or greater than the tensile strength TS2M of the biaxially stretched plastic film in the machine direction. The ratio of the tensile strength TS2T in the perpendicular direction to the tensile strength TS2M in the machine direction, TS2T / TS2M, is 1.00 or greater, and may be 1.05 or greater. TS2T / TS2M is, for example, 1.20 or less, and may be 1.15 or less.

[0043] The tensile modulus TM2T of the biaxially stretched plastic film in the perpendicular direction is, for example, 3500 MPa or more, may be 3700 MPa or more, or may be 3900 MPa or more. The tensile modulus TM2T of the biaxially stretched plastic film in the perpendicular direction is, for example, 4500 MPa or less, may be 4300 MPa or less, or may be 4100 MPa or less.

[0044] The tensile elongation TE2M of the biaxially stretched plastic film in the machine direction may be equal to or greater than the tensile elongation TE2T of the biaxially stretched plastic film in the perpendicular direction. TE2M / TE2T, which is the ratio of the tensile elongation TE2M in the machine direction to the tensile elongation TE2T in the perpendicular direction, is, for example, 1.00 or more, and may be 1.01 or more. TE2M / TE2T is, for example, 1.15 or less, and may be 1.10 or less, or may be 1.05 or less. The tensile elongation TE2M and the tensile elongation TE2T are, for example, 100% or more, and may be 105% or more. The tensile elongation TE2M and the tensile elongation TE2T are, for example, 120% or less, and may be 115% or less.

[0045] The tensile strength, tensile modulus and tensile elongation are measured in accordance with JIS K7127. The measuring device used is a tensile tester RTC-1310A manufactured by Orientec Co., Ltd. The test piece used is a rectangular film cut from a biaxially stretched plastic film with a width of 15 mm and a length of 150 mm. The distance between the pair of chucks holding the test piece at the start of the measurement is 100 mm, and the tensile speed is 300 mm / min. The length of the test piece can be adjusted as long as the test piece can be held by the pair of chucks. In this application, unless otherwise specified, the environmental temperature during the test is 25°C and the relative humidity is 50%. The average values ​​of the measured values ​​of five test pieces are used as the tensile strength, tensile modulus and tensile elongation in this application.

[0046] A stretched plastic film such as a biaxially stretched plastic film may contain polyester as a main component. For example, the stretched plastic film may contain 51% by mass or more of polyester. The first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53 may all contain polyester as a main component. Examples of polyester include polyethylene terephthalate (hereinafter also referred to as PET), polybutylene terephthalate (hereinafter also referred to as PBT), etc. The 51% by mass or more of polyester in the stretched plastic film may be composed of one type of polyester, or may be composed of two or more types of polyester. The content of polyester in the stretched plastic film may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more. For example, the content of PET in the stretched plastic film may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.

[0047] A stretched plastic film such as a biaxially stretched plastic film may contain polyamide as a main component. For example, the stretched plastic film may contain 51% by mass or more of polyamide. An example of polyamide is nylon. The content of polyamide in the stretched plastic film may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.

[0048] The compositions of the first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53 may be the same or different. For example, the polyester contents of the first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53 may be the same or different.

[0049] The thickness of the stretched plastic film is, for example, 8 μm or more, and may be 10 μm or more, 11 μm or more, or 12 μm or more. The thickness of the stretched plastic film is, for example, 25 μm or less, and may be 20 μm or less. When the stretched plastic film has a thickness of 8 μm or more, the strength of the packaging material 50 can be ensured. When the stretched plastic film has a thickness of 25 μm or less, the formability of the packaging material 50 can be ensured.

[0050] The packaging material 50 may not include any stretched plastic films other than the first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53. In other words, the stretched plastic films included in the packaging material 50 may only be the first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53. This form can reduce the thickness and cost of the packaging material 50 compared to when the packaging material 50 includes four or more stretched plastic films.

[0051] The thickness of the packaging material 50 is, for example, 150 μm or less, may be 140 μm or less, may be 130 μm or less, may be 120 μm or less, or may be 110 μm or less. The thickness of the packaging material 50 is, for example, 75 μm or more, may be 90 μm or more, or may be 100 μm or more.

[0052] The thickness of the layers constituting the packaging material 50, such as the stretched plastic film, is calculated by observing a cross section of a sample of the packaging material 50. The process of calculating the thickness includes a block preparation process, a block cutting process, and an observation process.

[0053] In the block preparation step, a sample obtained by cutting out a part of the packaging material 50 is embedded in resin to prepare a block. In the block cutting step, the block is cut using a rotary microtome in an environment of 25°C. The block is cut along a direction perpendicular to the outer surface 50y of the packaging material 50. This results in a cross section of the packaging material 50. The block cutting step includes a step of further cutting the packaging material 50 using a diamond knife. This further smooths the cross section of the packaging material 50. In the observation step, the cross section of the packaging material 50 is observed by a scanning electron microscope. The layer thickness is measured at five points on the cross section. The layer thickness is calculated by averaging the five measured values.

[0054] [Sealant film] The sealant film 55 forms the sealed portion of the pouch by melting through heat sealing. The sealant film 55 is an unstretched polypropylene film. The term "unstretched" refers not only to a film that is not stretched at all, but also to a film that is slightly stretched due to the tension applied during film formation.

[0055] The sealant film 55 may be a single layer. That is, the sealant film 55 may be composed of one layer. The sealant film 55 may be a multilayer. That is, the sealant film 55 may include a plurality of layers. Preferably, the sealant film 55 is a single layer.

[0056] The pouch 10 made of the packaging material 50 is subjected to a sterilization treatment such as boiling or retort treatment at high temperatures. The sealant film 55 has heat resistance that allows it to withstand such high temperature treatments.

[0057] The melting point of the material constituting the sealant film 55 is preferably 150° C. or higher, and more preferably 160° C. or higher. By increasing the melting point of the sealant film 55, it becomes possible to perform the retort treatment of the pouch 10 at a high temperature, and therefore the time required for the retort treatment can be shortened. The melting point of the material constituting the non-oriented polypropylene film is lower than the melting point of the oriented plastic film.

[0058] The sealant film 55 contains propylene as a main component. For example, the sealant film 55 contains a first thermoplastic resin made of polypropylene. The content of propylene in the sealant film 55 is, for example, 90 mass % or more.

[0059] The first thermoplastic resin may be a block polypropylene. The block polypropylene is a copolymer containing at least a homopolypropylene and a block elastomer. An example of the block polypropylene is a propylene-ethylene block copolymer.

[0060] The block polypropylene may contain a polymer part (a) made of a propylene polymer and a polymer part (b) made of polyethylene and an ethylene-propylene copolymer rubber component. The block polypropylene may contain a sea component made of a propylene polymer and an island component made of polyethylene and an ethylene-propylene copolymer rubber component. The polymer part (a) and the sea component can contribute to improving the heat resistance, rigidity, blocking resistance and seal strength of the block polypropylene. The polymer part (b) and the island component can contribute to improving the impact resistance of the block polypropylene. Therefore, by adjusting the ratio of the polymer part (a) to the polymer part (b) and the ratio of the sea component to the island component, the mechanical properties of the sealant film 55 containing the block polypropylene can be adjusted.

[0061] The propylene polymer of the polymer portion (a) is, for example, a propylene homopolymer having a melting point of 160° C. or higher. The propylene polymer may be a copolymer of propylene and a small amount (for example, 5 mol % or less) of an α-olefin, so long as the melting point is 160° C. or higher. Examples of the α-olefin include ethylene, 1-butene, 1-hexene, and 1-octene.

[0062] In the polymer part (b), for example, in the polyethylene and ethylene-propylene copolymer rubber components, the content ratio of ethylene-derived structural units may be 20% by mass or more and 50% by mass or less. This can further improve, for example, drop impact resistance. In the present disclosure, the content ratio of structural units can be measured, for example, by NMR. In the polymer part (b), the ethylene-propylene copolymer rubber component corresponds to a block elastomer.

[0063] In the block polypropylene, the mass ratio of the polymer portion (a) made of a propylene polymer or the sea component is preferably higher than the mass ratio of the polymer portion (b) made of polyethylene and an ethylene-propylene copolymer rubber component or the island component.

[0064] In the block polypropylene, the mass ratio of the polymer part (a) made of a propylene polymer or the sea component is preferably 51 mass% or more, more preferably 60 mass% or more, and further preferably 70 mass% or more. The upper limit of the mass ratio of the polymer part (a) made of a propylene polymer or the sea component is, for example, 90 mass%.

[0065] In the block polypropylene, the mass ratio of the polymer portion (b) consisting of polyethylene and ethylene-propylene copolymer rubber components or the island components is preferably 49 mass% or less, more preferably 40 mass% or less, and further preferably 30 mass% or less. The lower limit of the mass ratio of the polymer portion (b) consisting of polyethylene and ethylene-propylene copolymer rubber components or the island components is, for example, 10 mass%.

[0066] The content of the first thermoplastic resin in the sealant film 55 is, for example, 70 mass % or more, optionally 75 mass % or more, optionally 80 mass % or more, or optionally 85 mass % or more. The content of the first thermoplastic resin in the sealant film 55 is, for example, 96 mass % or less, or optionally 90 mass % or less.

[0067] The sealant film 55 may contain a second thermoplastic resin in addition to the first thermoplastic resin. The second thermoplastic resin may be dispersed in the first thermoplastic resin. The second thermoplastic resin may be polyethylene. The polyethylene may contribute to increasing the impact resistance of the sealant film 55. Examples of polyethylene include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc.

[0068] The content of the second thermoplastic resin in the sealant film 55 is lower than the content of the first thermoplastic resin in the sealant film 55. The content of the second thermoplastic resin in the sealant film 55 is, for example, 2 mass% or more, optionally 4 mass% or more, optionally 10 mass% or more, or optionally 15 mass% or more. The content of the second thermoplastic resin in the sealant film 55 is, for example, 30 mass% or less, optionally 20 mass% or less, optionally 15 mass% or less, or optionally 10 mass% or less.

[0069] The sealant film 55 may include a third thermoplastic resin in addition to the first thermoplastic resin. The sealant film 55 may include a third thermoplastic resin in addition to the first thermoplastic resin and the second thermoplastic resin. The third thermoplastic resin may be dispersed in the first thermoplastic resin. The third thermoplastic resin may be an elastomer. The elastomer may contribute to increasing the impact resistance of the sealant film 55. Examples of the elastomer include a propylene-ethylene copolymer (propylene-ethylene elastomer), an ethylene-α-olefin copolymer (ethylene-α-olefin elastomer), and the like.

[0070] The content of the third thermoplastic resin in the sealant film 55 is lower than the content of the first thermoplastic resin in the sealant film 55. The content of the third thermoplastic resin in the sealant film 55 is, for example, 2 mass% or more, and may be 4 mass% or more. The content of the third thermoplastic resin in the sealant film 55 is, for example, 10 mass% or less, and may be 8 mass% or less.

[0071] The thickness of the sealant film 55 is, for example, 30 μm or more, may be 40 μm or more, may be 50 μm or more, or may be 60 μm or more. The thickness of the sealant film 55 is, for example, 100 μm or less, and may be 80 μm or less.

[0072] There are three possible types of sealant film 55 containing the first thermoplastic resin made of block polypropylene.

[0073] The first type sealant film 55 is a single-layer unstretched polypropylene film that contains a first thermoplastic resin having the above-mentioned content and a second thermoplastic resin having the above-mentioned content, but does not contain a third thermoplastic resin having the above-mentioned content. The first type sealant film 55 has high tensile elongation and impact resistance. The first type sealant film 55 preferably further has a property of low hot seal strength. This can prevent the pressure of the containing part from becoming excessive when the pouch is heated. This can prevent damage to the packaging material.

[0074] The second type of sealant film 55 is a single-layer unstretched polypropylene film containing a first thermoplastic resin having the above-mentioned content, a second thermoplastic resin having the above-mentioned content, and a third thermoplastic resin having the above-mentioned content. The second type of sealant film 55 has a high tensile modulus. By using the second type of sealant film 55, it is possible to improve the tearability when opening the pouch.

[0075] The third type of sealant film 55 is a single-layer unstretched polypropylene film that contains a first thermoplastic resin having the above-mentioned content, but does not contain a second thermoplastic resin having the above-mentioned content, or a third thermoplastic resin having the above-mentioned content.

[0076] In this embodiment, preferably, the packaging material 50 includes the first type sealant film 55 or the second type sealant film 55. In this embodiment, more preferably, the packaging material 50 includes the first type sealant film 55.

[0077] The first type sealant film 55 will be described in detail. The content of the first thermoplastic resin in the first type sealant film 55 is, for example, 70 mass % or more, and may be 75 mass % or more. The content of the first thermoplastic resin is, for example, 85 mass % or less, and may be 80 mass % or less.

[0078] In the first type sealant film 55, the polyethylene of the second thermoplastic resin has a viscosity of 0.90 g / cm 3 Above 0.93g / cm 3 The sealant film 55 may have a density of 15% by mass or less, and may have a density of 25% by mass or less. The polyethylene may be linear low-density polyethylene. The content of the second thermoplastic resin in the sealant film 55 is, for example, 15% by mass or more, and may be 20% by mass or more. The content of the second thermoplastic resin in the sealant film 55 is, for example, 30% by mass or less, and may be 25% by mass or less.

[0079] The tensile elongation of the first type sealant film 55 in the machine direction (MD) at 23°C is, for example, 800% or more, may be 900% or more, may be 1000% or more, or may be 1100% or more. The product of the tensile elongation (%) and the thickness (μm) of the first type sealant film 55 in the machine direction (MD) is, for example, 45000 or more, may be 50000 or more, may be 55000 or more, or may be 60000 or more. The tensile elongation of the first type sealant film 55 in the transverse direction (TD) at 23°C is, for example, 1050% or more, may be 1100% or more. The product of the tensile elongation (%) and the thickness (μm) of the first type sealant film 55 in the transverse direction (TD) is, for example, 53000 or more, may be 60000 or more. The sealant film 55 has a high tensile elongation, so that the pouch 10 can be prevented from breaking due to an impact when dropped, for example.

[0080] The Young's modulus of the first type sealant film 55 in the machine direction (MD) at 23°C is, for example, 670 MPa or less, and may be 650 MPa or less. The product of the Young's modulus (MPa) and thickness (μm) of the first type sealant film 55 in the machine direction (MD) is, for example, 38000 or less, and may be 35000 or less. The Young's modulus of the first type sealant film 55 in the transverse direction (TD) at 23°C is, for example, 550 MPa or less, and may be 500 MPa or less. The product of the Young's modulus (MPa) and thickness (μm) of the first type sealant film 55 in the transverse direction (TD) is, for example, 30000 or less, and may be 25000 or less.

[0081] The thickness of the first type sealant film 55 is, for example, 30 μm or more, may be 40 μm or more, may be 50 μm or more, or may be 60 μm or more. The thickness of the first type sealant film 55 is, for example, 100 μm or less, and may be 80 μm or less.

[0082] The second type sealant film 55 will be described in detail. The content of the first thermoplastic resin in the second type sealant film 55 is, for example, 80% by mass or more, and may be 85% by mass or more. The content of the first thermoplastic resin is, for example, 96% by mass or less, and may be 90% by mass or less.

[0083] In the second type sealant film 55, the polyethylene of the second thermoplastic resin has a viscosity of 0.94 g / cm 3 Above 0.97g / cm 3 The sealant film 55 may have a density of 100% or less. The content of the second thermoplastic resin in the sealant film 55 is, for example, 2% by mass or more, and may be 4% by mass or more. The content of the second thermoplastic resin in the sealant film 55 is, for example, 10% by mass or less, and may be 8% by mass or less.

[0084] In the second type sealant film 55, the third thermoplastic resin elastomer may be an ethylene-α-olefin copolymer elastomer. The ethylene-α-olefin copolymer elastomer may contain an α-olefin having 3 to 10 carbon atoms and ethylene. The ethylene-α-olefin copolymer elastomer has a viscosity of 0.86 g / cm. 3 More than 0.90g / cm 3 The sealant film 55 may have a density of 100% or less. The content of the third thermoplastic resin in the sealant film 55 is, for example, 2% by mass or more, and may be 4% by mass or more. The content of the third thermoplastic resin in the sealant film 55 is, for example, 10% by mass or less, and may be 8% by mass or less.

[0085] The Young's modulus of the second type sealant film 55 in the machine direction (MD) at 23°C is, for example, 500 MPa or more, may be 600 MPa or more, may be 650 MPa or more, or may be 700 MPa or more. The product of the Young's modulus (MPa) and thickness (μm) of the second type sealant film 55 in the machine direction (MD) is, for example, 35,000 or more, may be 38,000 or more, or may be 45,000 or more. The Young's modulus of the second type sealant film 55 in the transverse direction (TD) at 23°C is, for example, 450 MPa or more, may be 500 MPa or more, may be 550 MPa or more, or may be 600 MPa or more. The product of the Young's modulus (MPa) and thickness (μm) of the second type sealant film 55 in the transverse direction (TD) is, for example, 25,000 or more, may be 30,000 or more, may be 35,000 or more, or may be 38,000 or more.

[0086] The tensile elongation of the second type sealant film 55 in the machine direction (MD) at 23°C is, for example, 1100% or less, may be 1000% or less, may be less than 1000%, may be 900% or less, or may be 800% or less. The product of the tensile elongation (%) and the thickness (μm) of the second type sealant film 55 in the machine direction (MD) may be, for example, 55000 or less, or may be 50000 or less. The tensile elongation of the second type sealant film 55 in the transverse direction (TD) at 23°C is, for example, 1200% or less, may be 1100% or less, may be less than 1100%, may be 1000% or less, or may be 900% or less. The product of the tensile elongation (%) and the thickness (μm) of the second type sealant film 55 in the transverse direction (TD) may be, for example, 60000 or less, or may be 55000 or less.

[0087] The thickness of the second type sealant film 55 is, for example, 30 μm or more, and may be 50 μm or more. The thickness of the second type sealant film 55 is, for example, 100 μm or less, and may be 80 μm or less.

[0088] The tensile modulus and tensile elongation of the sealant film 55 are measured in accordance with JIS K7127. A tensile tester RTC-1310A manufactured by Orientec Co., Ltd. is used as a measuring instrument. A rectangular film having a width of 15 mm and a length of 150 mm is cut from the sealant film 55 and used as a test piece. The distance between the pair of chucks holding the test piece at the start of the measurement is 100 mm, and the tensile speed is 300 mm / min. The length of the test piece can be adjusted as long as the test piece can be held by the pair of chucks. In this application, unless otherwise specified, the environmental temperature during the test is 25°C and the relative humidity is 50%. The average values ​​of the measured values ​​of five test pieces are used as the tensile modulus and tensile elongation of this application.

[0089] [Transparent vapor deposited layer] Next, the transparent vapor deposition layer 62 will be described. The transparent vapor deposition layer 62 is a transparent layer formed by a vapor deposition method or the like. The transparent vapor deposition layer 62 enhances the gas barrier properties of the packaging material 50. For example, the transparent vapor deposition layer 62 suppresses the transmission of gases such as oxygen gas and water vapor through the packaging material 50.

[0090] The transparent deposition layer 62 is made of one or more materials selected from the group consisting of metal oxides such as aluminum oxide, and inorganic compounds such as silicon oxide.

[0091] The transparent deposition layer 62 may be composed of a single layer or multiple layers. Each of the single layer and multiple layers contains one or more materials selected from the above group. When the transparent deposition layer 62 includes multiple layers, each layer may contain the same material or different materials.

[0092] The transparent deposition layer 62 may be an amorphous thin film of aluminum oxide. Specifically, the transparent deposition layer 62 may be a thin film of the formula AlO X (wherein X is a number in the range of 0.5 to 1.5). As the transparent deposition layer 62, an amorphous thin film of aluminum oxide in which the value of X decreases in the depth direction from the film surface toward the inner surface can also be used. The amorphous thin film of aluminum oxide is represented by the formula AlO X (wherein X is a number in the range of 0.5 to 1.5), and it is preferable that the value of X increases in the depth direction from the surface of the thin film toward the inner surface. In the above formula, the value of X can basically be 0.5 or more, but if it is less than 1.0, coloring is severe and transparency is poor, so it is preferable to use X=1.0 or more. In addition, since X=1.5 is a state in which Al and oxygen are completely oxidized, the upper limit of X=1.5 can be used. In addition, when the value of X in the above formula is 0, it is a completely inorganic simple substance (pure substance) and is not transparent.

[0093] The value of X is calculated by analyzing the transparent deposition layer 62 in the depth direction using an X-ray Photoelectron Spectroscopy (XPS).

[0094] The transparent vapor deposition layer 62 has a thickness of, for example, 3 nm or more, optionally 10 nm or more, or 15 nm or more. The transparent vapor deposition layer 62 has a thickness of, for example, 50 nm or less, optionally 40 nm or less, or 30 nm or less.

[0095] Methods for forming the transparent deposition layer 62 include, for example, physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, or chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0096] The surface of the stretched plastic film on which the transparent deposition layer 62 is formed may be treated to enhance adhesion, or a layer for enhancing adhesion may be formed thereon. The treatment may be, for example, a plasma treatment.

[0097] [Gas barrier coating film] Next, the gas barrier coating film 63 provided on the surface of the transparent vapor deposition layer 62 will be described.

[0098] The gas barrier coating film 63 is made of a gas barrier composition polycondensed by a sol-gel method. The gas barrier composition contains at least one alkoxide, a polyvinyl alcohol resin and / or an ethylene-vinyl alcohol copolymer. The gas barrier composition further contains a sol-gel catalyst, an acid, water, and an organic solvent. The gas barrier coating film 63 is preferably transparent.

[0099] The above general formula R 1 n M(OR 2 ) mAs the alkoxide represented by the formula (I), at least one of a partial hydrolyzate of an alkoxide and a condensate of hydrolysis of an alkoxide is used. In the partial hydrolyzate of an alkoxide, it is not necessary that all of the alkoxy groups are hydrolyzed. The partial hydrolyzate of an alkoxide may be one in which one or more alkoxy groups are hydrolyzed, or a mixture thereof. As the condensate of hydrolysis of an alkoxide, a dimer or more of a partially hydrolyzed alkoxide, specifically, a dimer to a hexamer, is used.

[0100] The above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula (I), the metal atom represented by M can be silicon, zirconium, titanium, aluminum, or the like. Preferred metals include, for example, silicon and titanium. In the present embodiment, the alkoxide can be used alone or in the form of a mixture of two or more different metal atoms in the same solution.

[0101] In addition, the above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula: 1 Specific examples of the organic group represented by the general formula R include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, n-octyl, and the like. 1 n M(OR 2 ) m In the alkoxide represented by the formula: 2 Specific examples of the organic group represented by the formula (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, etc. In addition, these alkyl groups may be the same or different in the same molecule.

[0102] When preparing the gas barrier composition, for example, a silane coupling agent may be added. As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group may be used. In particular, an organoalkoxysilane having an epoxy group is preferably used, and specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane may be used. The silane coupling agents may be used alone or in combination of two or more.

[0103] [Print layer] The printing layer 61 is a layer that forms any desired printed pattern such as letters, numbers, pictures, figures, symbols, designs, etc. for decoration, display of contents, display of expiration date, display of manufacturer, seller, etc., and for imparting aesthetic appeal. The printing layer 61 is provided as necessary. For example, the printing layer 61 is provided between the first stretched plastic film 51 and the first adhesive layer 56. The printing layer 61 may be provided on the entire surface of the first stretched plastic film 51, or may be provided on only a part of it.

[0104] The thickness of the printed layer 61 is, for example, 0.1 μm or more, may be 0.5 μm or more, or may be 1.0 μm or more. The thickness of the printed layer 61 is, for example, 10 μm or less, may be 5.0 μm or less, or may be 3.0 μm or less.

[0105] The printing layer 61 is formed by applying and drying a printing composition for forming the printing layer 61. The printing composition contains a coloring material such as a pigment or a dye. The coloring material may contain an inorganic pigment. The inorganic pigment may contain a metal component. For example, the inorganic pigment may contain an oxide of a metal such as iron, copper, or lead.

[0106] The coating amount of the printing composition is, for example, 0.5 g / m 2 More than 1.0 g / m 2 or more, 1.5 g / m 2The coating amount of the printing composition may be, for example, 4.0 g / m 2 Less than or equal to 3.0 g / m 2 or less, 2.5 g / m 2 It may be less than 1 μm.

[0107] [Adhesive layer] The first adhesive layer 56 is a layer formed by applying an adhesive to the surface of the film including the first stretched plastic film 51 and the film including the second stretched plastic film 52, which is the film that is to be laminated, and drying the adhesive. The second adhesive layer 57 is a layer formed by applying an adhesive to the surface of the film including the second stretched plastic film 52 and the film including the third stretched plastic film 53, which is the film that is to be laminated, and drying the adhesive. The third adhesive layer 58 is a layer formed by applying an adhesive to the surface of the film including the third stretched plastic film 53 and the film including the sealant film 55, which is the film that is to be laminated, and drying the adhesive. As the adhesive constituting the adhesive layers such as the first adhesive layer 56, the second adhesive layer 57, and the third adhesive layer 58, for example, one-component or two-component curing or non-curing type vinyl-based, (meth)acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, rubber-based, and other solvent-based, water-based, or emulsion-based adhesives can be used. As the two-liquid curing adhesive, a cured product of polyol and isocyanate compound can be used. The above-mentioned laminating adhesive can be applied by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fountain method, a transfer roll coating method, or other methods.

[0108] At least one of the first adhesive layer 56, the second adhesive layer 57, and the third adhesive layer 58, which is located on the inner side of the transparent vapor deposition layer 62 in the thickness direction, contains an oxygen-absorbing adhesive composition. The oxygen-absorbing adhesive composition is a composition for forming an adhesive capable of absorbing oxygen. The adhesive layer containing the oxygen-absorbing adhesive composition can absorb oxygen present in the storage section of the pouch composed of the packaging material 50. This can suppress the oxidation of the contents stored in the storage section. In the following description, the adhesive layer containing the oxygen-absorbing adhesive composition is also referred to as a special adhesive layer. In the above-mentioned packaging material 50 shown in Figures 1 to 3, the second adhesive layer 57 may be a special adhesive layer. Details of the oxygen-absorbing adhesive composition will be described later.

[0109] The adhesive layers other than the special adhesive layer may not contain the oxygen-absorbing adhesive composition. An adhesive layer that does not contain the oxygen-absorbing adhesive composition is also referred to as a normal adhesive layer.

[0110] The above-mentioned sealant film 55 may contain an antioxidant. In this case, it is preferable that the special adhesive layer is not in contact with the sealant film 55. For example, when the third adhesive layer 58 is in contact with the sealant film 55, it is preferable that the third adhesive layer 58 is a normal adhesive layer rather than a special adhesive layer. This can prevent the oxygen absorbing performance of the special adhesive layer from being inhibited by the antioxidant contained in the sealant film 55. Details of the antioxidant will be described later.

[0111] The content of the antioxidant in the sealant film 55 is, for example, 100 ppm or more, may be 500 ppm or more, or may be 1000 ppm or more. The content of the antioxidant in the sealant film 55 is, for example, 10000 ppm or less, may be 7000 ppm or less, or may be 5000 ppm or less.

[0112] When the printed layer 61 contains a metal component, it is preferable that the special adhesive layer is not in contact with the printed layer 61. For example, when the first adhesive layer 56 is in contact with the printed layer 61, it is preferable that the first adhesive layer 56 is a normal adhesive layer rather than a special adhesive layer. This can prevent the oxygen absorption performance of the special adhesive layer from being inhibited by the metal components contained in the printed layer 61. In addition, it can prevent the adhesive strength of the special adhesive layer from being reduced by the metal components contained in the printed layer 61. This can prevent peeling between the printed layer 61 and the first adhesive layer 56.

[0113] When the printed layer 61 does not contain a metal component, the first adhesive layer 56 may be a special adhesive layer. In this case, the second adhesive layer 57 may be a special adhesive layer or a normal adhesive layer.

[0114] When the packaging material 50 does not include the printed layer 61, the first adhesive layer 56 may be a special adhesive layer. In this case, the second adhesive layer 57 may be a special adhesive layer or a normal adhesive layer.

[0115] The thickness of the adhesive layers 56, 57, 58 after drying is, for example, 0.5 μm or more, may be 1.0 μm or more, may be 1.5 μm or more, or may be 2.0 μm or more. The thickness of the adhesive layers 56, 57, 58 after drying is, for example, 10 μm or less, may be 7.0 μm or less, may be 6.0 μm or less, or may be 4.5 μm or less.

[0116] The amount of adhesive applied to form the adhesive layers 56, 57, and 58 is, for example, 1.0 g / m 2 More than 2.0 g / m 2 or more, and 2 The amount of adhesive applied may be, for example, 7.0 g / m 2 Less than or equal to 6.0 g / m 2 or less, 5.0 g / m 2 It may be less than 1 μm.

[0117] The oxygen-absorbing adhesive composition will be described in detail. The oxygen-absorbing adhesive composition contains at least an oxygen-absorbing compound and an oxidation-promoting catalyst. The oxygen-absorbing adhesive composition may further contain a modifier, a diluting solvent, various additives, etc., as necessary.

[0118] The oxygen-absorbing adhesive composition may be prepared by adding an oxygen-absorbing compound to an existing adhesive composition. The oxygen-absorbing adhesive composition may be prepared by using an oxygen-absorbing compound as a resin component of an adhesive. The existing oxygen-absorbing adhesive composition may be a one-liquid oxygen-absorbing adhesive composition or a two-liquid oxygen-absorbing adhesive composition.

[0119] The oxygen-absorbing adhesive composition may contain one or more oxygen-absorbing compounds. The oxygen-absorbing adhesive composition and / or the above-mentioned existing adhesive composition may or may not have curing properties. The curing properties may be, for example, thermosetting, photocuring, electron beam curing, etc.

[0120] The oxygen absorbing compound may or may not be reactive with components contained in existing adhesive compositions. The oxygen absorbing compounds may react with each other. The oxygen absorbing compound may contain one or more compounds selected from compounds that do not contain a functional group, compounds that contain a polymerizable or copolymerizable functional group, and compounds that contain a functional group that can react as a base agent or a curing agent.

[0121] For example, an oxygen absorbing compound that does not contain a functional group and / or an oxygen absorbing compound that contains a functional group may be added to a two-liquid urethane adhesive composition that contains an isocyanate compound and a hydroxyl group-containing compound. In this case, the functional group is preferably an isocyanate group and / or a hydroxyl group.

[0122] Examples of combinations of base agents and curing agents for oxygen-absorbing adhesive compositions are shown below. A combination of an isocyanate compound and an oxygen-absorbing compound containing a hydroxyl group A combination of a hydroxyl group-containing compound and an oxygen-absorbing compound containing an isocyanate group A combination of an oxygen absorbing compound containing a hydroxyl group and an oxygen absorbing compound containing an isocyanate group.

[0123] The oxygen absorbing adhesive composition is preferably a urethane-based oxygen absorbing adhesive composition.

[0124] The solid content in the oxygen-absorbing adhesive composition is not particularly limited, but is preferably 20% by mass or more and 100% by mass or less.

[0125] The solid content of the oxygen absorbing adhesive composition is composed of a first solid content and a second solid content consisting of an oxidation-promoting catalyst. The content of the oxygen absorbing compound in the first solid content is preferably 40% by mass or more and 100% by mass or less. If the content of the oxygen absorbing compound is less than the above range, there is a risk that the oxygen absorption will be insufficient. When the content of the oxygen absorbing compound is 100% by mass, the oxygen absorbing compound can be used as a resin component of the adhesive composition. For example, when the content is 100% by mass, the oxygen absorbing compound has sufficient adhesiveness by itself, when the oxygen absorbing compound contains a functional group that can be cured by itself, when an oxygen absorbing compound containing a functional group that serves as a main agent and an oxygen absorbing compound containing a functional group that serves as a curing agent are mixed and used.

[0126] From the viewpoint of oxygen absorption, the content of the oxidation-promoting catalyst in the oxygen-absorbing adhesive composition is preferably 10 ppm or more and 6000 ppm or less relative to the oxygen-absorbing compound. If the content is less than the above range, the oxygen absorption may be insufficient. If the content is more than the above range, the oxygen absorption may be unstable, and the oxygen absorption may be consumed before the package is produced, which may impair the effect of suppressing deterioration of the package contents due to oxygen after the package is produced.

[0127] [Oxygen absorbing compound] The oxygen absorbing compound according to the embodiment of the present disclosure has oxygen absorbing properties, generates little odor, and can be used alone or can be mixed with a resin or a resin composition.

[0128] The oxygen absorbing compound according to the embodiment of the present disclosure includes one or more unsaturated five-membered rings. Any bond between the five carbon atoms constituting the unsaturated five-membered ring is a carbon-carbon double bond. A monovalent and / or divalent or higher electron-donating organic group 1 is bonded to the unsaturated five-membered ring.

[0129] When there is one unsaturated five-membered ring, the five-membered ring or organic group 1 contains a functional group containing active hydrogen, or a group in which the active hydrogen of the functional group containing active hydrogen is substituted with a monovalent organic group 2. When there are two or more unsaturated five-membered rings, the unsaturated five-membered rings are bonded to each other via a divalent or higher organic group 2 that substitutes the active hydrogen of the active hydrogen group on each organic group 1.

[0130] When there are two or more unsaturated five-membered rings in one molecule, the unsaturated five-membered rings are bonded to each other via a structure in which the active hydrogen of a functional group containing active hydrogen on each of the five-membered rings or organic group 1 is substituted with a divalent or higher organic group 2.

[0131] The unsaturated five-membered ring, organic group 1, and organic group 2 present in one molecule may each be one or two or more kinds, and the number may be one or two or more. The organic group 1 bonded to one unsaturated five-membered ring may be one or two or more. Furthermore, the oxygen-absorbing compound may be a mixture of molecules having two or more structures in which the types and numbers of the unsaturated five-membered ring, organic group 1, and organic group 2 present in one molecule are different, as described above.

[0132] By the organic group 1 donating electrons to the unsaturated five-membered ring, the electron density of the carbon-carbon double bond portion contained in the unsaturated five-membered ring increases, the reactivity with oxygen increases, and the oxygen absorption increases. It is preferable that no electron-withdrawing group is bonded to the unsaturated five-membered ring. By the electron-withdrawing group being bonded, the electron density of the carbon-carbon double bond portion contained in the unsaturated five-membered ring decreases, the reactivity with oxygen decreases, and the oxygen absorption decreases.

[0133] Specific molecular structures of the oxygen-absorbing compound include, for example, one unsaturated five-membered ring bonded to a monovalent or divalent organic group 1, one unsaturated five-membered ring bonded to a monovalent or divalent organic group 1 and a monovalent organic group 2 in that order, two unsaturated five-membered rings bonded via a divalent organic group 1 and a divalent organic group 2, and three unsaturated five-membered rings bonded via a divalent organic group 1 and a trivalent organic group 2.

[0134] The oxygen absorbing compound may not contain a crosslinkable functional group, but may contain one. The crosslinkable functional group may be a functional group contained in the compound from which the organic group 2 is derived, or may be a functional group added by chemical modification. When the oxygen absorbing compound contains a crosslinkable functional group, the oxygen absorbing compound is more compatible with the resin or resin composition when mixed with the resin or resin composition, or becomes a part of the crosslinked structure of the resin or resin composition, and is less likely to bleed from the resin, resin composition, or cured resin composition, thereby increasing the content of the oxygen absorbing compound in the resin or resin composition.

[0135] Specific examples of the crosslinkable functional group include an aliphatic hydroxyl group, an aromatic hydroxyl group, an isocyanate group, an amino group, an epoxy group, and a (meth)acrylic group. Among these, an isocyanate group and an aliphatic hydroxyl group are preferable. The number of the crosslinkable functional group contained in the oxygen absorbing compound is preferably 1 or 2 or more in one molecule. The number of the crosslinkable functional groups contained in one molecule may be one type or two or more types. The functional group equivalent of the crosslinkable functional group is not particularly limited, but is preferably 500 to 20,000, more preferably 1,000 to 15,000, and further preferably 1,500 to 10,000.

[0136] The number average molecular weight of the oxygen absorbing compound is preferably 100 to 10,000, more preferably 200 to 5,000, and even more preferably 300 to 2,500. If the number average molecular weight is smaller than the above range, it is likely to precipitate when mixed with a resin or a resin composition. If the number average molecular weight is larger than the above range, it is likely to require a large amount of dilution solvent to be included when mixed with a resin or a resin composition because the viscosity of the mixture increases, making it difficult to obtain a thick film or layer, and coating suitability is likely to deteriorate.

[0137] The oxygen absorbing action of the oxygen absorbing compound according to the embodiment of the present disclosure may be accelerated by heating or the addition of a catalyst.

[0138] (unsaturated five-membered ring) The unsaturated five-membered ring contained in the oxygen absorbing compound contains a carbon-carbon double bond within the unsaturated five-membered ring. The carbon-carbon double bond is any bond between the five carbon atoms constituting the unsaturated five-membered ring, and may be one or two within one unsaturated five-membered ring. The carbon-carbon double bond reacts with oxygen molecules in the air to capture the oxygen molecules, and the oxygen absorbing compound exhibits oxygen absorbing properties.

[0139] Examples of compounds from which the above-mentioned unsaturated five-membered ring or the unsaturated five-membered ring to which the electron-donating organic group 1 is bonded include cyclopentadiene, dicyclopentadiene, norbornene, and derivatives thereof. The oxygen-absorbing compound can contain an unsaturated five-membered ring derived from one or more of these selected from the group consisting of these.

[0140] The concentration of the unsaturated five-membered ring in the oxygen absorbing compound is, for example, 1% by mass or more, and may be 5% by mass or more. The concentration of the unsaturated five-membered ring in the oxygen absorbing compound is, for example, 70% by mass or less, and may be 60% by mass or less. If the concentration of the unsaturated five-membered ring is lower than the above range, the oxygen absorbing property tends to be insufficient. It is difficult to obtain an oxygen absorbing compound having a concentration of the unsaturated five-membered ring higher than the above range, and the balance of various physical properties tends to be poor.

[0141] (Electron-donating organic group 1) Specific examples of the organic group 1 include, for example, an alkyl group, an alkylene group, and a cyclic alkylene group. Among these, a cyclic alkylene group is preferred, and those that form an aliphatic bicyclic alkylene group together with an unsaturated five-membered ring are more preferred. Specific examples of the cyclic alkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, and a cyclooctylene group. Among these, a cyclopentylene group is more preferred.

[0142] (Electron-withdrawing organic group) Specific examples of the electron-withdrawing group include a phenyl group, a phenylene group, a carbonyl group, a halogen, etc. Indene and coumarone in which only these electron-withdrawing groups are bonded to an unsaturated five-membered ring have a low electron density in the carbon-carbon double bond portion contained in the unsaturated five-membered ring, which reduces the reactivity with oxygen and results in low oxygen absorption.

[0143] (functional group containing active hydrogen) The functional group containing active hydrogen is chemically active. Specific examples of the functional group containing active hydrogen include a primary amino group, a secondary amino group, an aliphatic hydroxyl group, an aromatic hydroxyl group, an imino group, a carboxyl group, a urethane group, and a urea group. Among these, a primary amino group, a secondary amino group, an aliphatic hydroxyl group, and an aromatic hydroxyl group are preferred, and an aliphatic hydroxyl group is more preferred.

[0144] (organic group 2) The organic group 2 is a monovalent and / or divalent or higher group that substitutes the active hydrogen of the functional group containing active hydrogen on the five-membered ring or organic group 1 and is bonded to the five-membered ring or organic group 1. When there are two or more unsaturated five-membered rings in one molecule, the unsaturated five-membered rings are bonded to each other via a structure in which the active hydrogen of the functional group containing active hydrogen is substituted with a divalent or higher organic group 2. As a specific example, for example, the functional group containing active hydrogen on the organic group 1 reacts with the isocyanate group of an isocyanate-based compound containing a structural part from which the organic group 2 is derived, and the active hydrogen is substituted with the organic group 2 and bonded by a urethane group. By bonding the organic group 2, the oxygen absorbing compound can contain two or more unsaturated five-membered rings in one molecule. Furthermore, the compatibility, dispersibility, and reactivity can be improved when the compound is mixed with a resin or a resin composition to prepare a mixture. Furthermore, the mixture or the cured product of the mixture can be adjusted to be soft.

[0145] The organic group 2 may be an aliphatic group, an aromatic group, or may contain both an aliphatic group and an aromatic group. The organic group 2 present in one molecule of the oxygen absorbing compound may be one type or two or more types. The organic group 2 is preferably a group containing a structural part derived from an isocyanate-based compound and / or a hydroxyl-containing compound. Here, the structural part derived from an isocyanate-based compound and / or a hydroxyl-containing compound also includes a structural part derived from a reaction product of an isocyanate-based compound and a hydroxyl-containing compound.

[0146] (Isocyanate compounds) Examples of isocyanate compounds from which the organic group 2 is derived include tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, norbornane diisocyanate, xylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, diphenylether diisocyanate, hydrogenated diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and their trimethylolpropane adducts, biuret bodies, allophanate bodies, isocyanurate bodies (trimers), and various derivatives thereof. Among these, biuret bodies of toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate are preferred. In the embodiment of the present disclosure, one or more selected from the group consisting of these isocyanate compounds can be used as the origin of the structural part of the monovalent and / or divalent or higher hydrocarbon group. When two or more types are used, the two types may be used in the same molecule of the oxygen-absorbing compound, or molecules of the oxygen-absorbing compound containing different types may be mixed.

[0147] The number average molecular weight of the isocyanate compound is preferably 100 to 10,000, more preferably 160 to 5,000. If the number average molecular weight is smaller than the above range, it is likely to precipitate when mixed with a resin or a resin composition. If the number average molecular weight is larger than the above range, it is likely to require a large amount of dilution solvent to be included when mixed with a resin or a resin composition because the viscosity of the mixture increases, making it difficult to obtain a thick film or layer, and coating suitability is likely to deteriorate.

[0148] (Hydroxy group-containing compound) The hydroxyl group-containing compound is a compound from which the organic group 2 is derived, and contains two or more hydroxyl groups. Examples of the hydroxyl group-containing compound include polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof. Among these, polyether polyols and polyolefin polyols are preferred. In order to prevent odor generation, the hydroxyl group-containing compound is preferably one that does not contain a double bond in the aliphatic chain of the main skeleton, or one that has two hydroxyl groups. Hydroxyl group-containing compounds that contain a hydroxyl group at the end are preferred in that they are easily available. The hydroxyl group-containing compound may contain a hydroxyl group at a position other than the end. In the embodiment of the present disclosure, one or more types selected from the group consisting of these can be used as the hydroxyl group-containing compound from which the organic group 2 is derived. When two or more types are used, two types may be used in the same molecule of the oxygen absorbing compound, or molecules of the oxygen absorbing compound containing different types may be mixed.

[0149] The number average molecular weight of the hydroxyl group-containing compound is preferably 500 to 10,000, more preferably 750 to 5,000, and even more preferably 1,000 to 3,000. If the number average molecular weight is smaller than the above range, precipitation is likely to occur when mixed with a resin or a resin composition. If the number average molecular weight is larger than the above range, the viscosity of the mixture increases when mixed with a resin or a resin composition, so that a large amount of dilution solvent is likely to be required, making it difficult to obtain a thick film or layer, and coating suitability is likely to deteriorate.

[0150] Polyhydric alcohols Polyhydric alcohols are monomers containing two or more hydroxyl groups. Specific examples of polyhydric alcohols include diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, cyclohexanedimethanol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,12-octadecanediol, and 2,2'-oxydiethanol, as well as glycerin, mannitol, and sorbitol. Among the above, ethylene glycol is preferred from the viewpoint of oxygen absorption.

[0151] Polyolefin polyol Polyolefin polyol is a polyolefin resin containing two or more hydroxyl groups. Specific examples of polyolefin polyols include those whose main skeleton is a polyolefin such as polyethylene, polypropylene, polybutylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-propylene copolymer, and also contain hydroxyl groups. Among these, those whose main skeleton is ethylene-vinyl acetate copolymer and hydrogenated polyisoprene are particularly preferred.

[0152] Polyether polyol The polyether polyol is a polyether resin having two or more hydroxyl groups. The polyether polyol is obtained, for example, by dehydration condensation of the above-mentioned polyhydric alcohols or polyolefin polyols, and contains a polyether structure in the main skeleton and contains a hydroxyl group. Specific examples of the polyether polyol include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene ether diol, polypropylene ether diol, polybutylene ether diol, and glycerin-modified polyether polyols. Among these, polypropylene ether diol is particularly preferred.

[0153] Polyester polyol The polyester polyol is a polyester resin containing two or more hydroxyl groups. The polyester polyol is obtained, for example, by esterification reaction between various polyvalent carboxylic acids or derivatives thereof and the above-mentioned polyhydric alcohols, polyolefin polyols, polyether polyols, etc., and contains a polyester structure in the main skeleton and contains hydroxyl groups. Specific examples of the polyvalent carboxylic acid include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, glutaric acid, 1,4-cyclohexanedicarboxylic acid, trimellitic acid, etc., and derivatives of these polyvalent carboxylic acids include esterified products, acid anhydrides, acylated products, etc. Among the above, polyester polyols in which two or more types of polyhydric alcohols and two or more types of polyvalent carboxylic acids are used in combination are preferred in order to reduce crystallinity.

[0154] Polycarbonate polyol Polycarbonate polyol is a polycarbonate-based resin containing two or more hydroxyl groups. Polycarbonate contains a polyol-derived portion in the main skeleton, and this polyol-derived portion may be derived from the above-mentioned polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, etc. Among these, polycarbonate polyols using two or more kinds of polyhydric alcohols in combination are preferred in order to reduce crystallinity.

[0155] Poly(meth)acrylic acid ester polyol Poly(meth)acrylic acid ester polyol is a (meth)acrylic acid ester (co)polymer containing two or more hydroxyl groups. Poly(meth)acrylic acid ester polyol can be obtained by, for example, using a hydroxyl group-containing monomer such as 2-hydroxyethyl methacrylate or a (meth)acrylic acid ester containing a hydroxyl group synthesized from one (meth)acrylic acid or its derivative and one diol, polymerizing the hydroxyl group-containing monomer with itself or copolymerizing it with a (meth)acrylic acid ester not containing a hydroxyl group. The diol used in synthesizing the (meth)acrylic acid ester containing a hydroxyl group can be the above-mentioned diols, polyolefin polyol, polyether polyol, etc. Among these, a poly(meth)acrylic acid ester copolymer using 2-hydroxyethyl methacrylate is preferred.

[0156] Phenoxy resin Phenoxy resin is a resin obtained by reacting a polyhydric phenol compound with a polyfunctional epoxy compound, and contains a structure in which an aliphatic hydroxyl group is generated at the bond formed by the reaction of an aromatic hydroxyl group with an epoxy group. As the phenoxy resin, one obtained by reacting a bisphenol with a diglycidyl etherified bisphenol is easily available and is common. Examples of the polyhydric phenol compound include bisphenol A and bisphenol F, and examples of the polyfunctional epoxy compound include bisphenol A diglycidyl ether and bisphenol F diglycidyl ether. Among these, phenoxy resin using bisphenol A is preferred. The terminal of the phenoxy resin may be an aromatic hydroxyl group or an epoxy group.

[0157] · Urethane chain-extended polyol The urethane chain-extended polyol is a polyol having two or more hydroxyl groups obtained by extending the above-mentioned hydroxyl group-containing compound with a urethane chain. The urethane chain-extended polyol can be obtained, for example, by polymerizing the above-mentioned various hydroxyl group-containing compounds with the above-mentioned isocyanate-based compounds to extend the urethane chain. If necessary, diamines or amino alcohols may be used in combination for polymerization. Among the above, the urethane chain-extended polyol obtained by reacting the above-mentioned various hydroxyl group-containing compounds containing hydroxyl groups at both ends with a diisocyanate-based compound is preferred.

[0158] (Specific examples of oxygen absorbing compounds) Specific examples of the oxygen-absorbing compound are given below.

[0159] 3a,4,5,6,7,7a-Hexahydro-4,7-methano-1H-indenol represented by formula (1), 3a,4,5,6,7,7a-Hexahydro-4,7-methano-1H-indenamine represented by formula (1-b), and 3a,4,5,6,7,7a-Hexahydro-4,7-methano-1H-inden-1-ol represented by formula (1-c) are examples of oxygen absorbing compounds containing one unsaturated five-membered ring and one organic group 1 containing a hydroxyl group or an amino group. The hydroxyl group or the amino group is a functional group containing active hydrogen. [ka] [ka] [ka]

[0160] The oxygen absorbing compound represented by formula (2) is, for example, a compound having a hydroxyl group, which is a functional group containing active hydrogen, on organic group 1 of the oxygen absorbing compound represented by formula (1), and an isocyanate compound R 1 (NCO) a reacts with the isocyanate group of R, replacing the active hydrogen of the hydroxyl group, and a number of unsaturated five-membered rings and organic group 1 are 1It is an oxygen absorbing compound that can be obtained by bonding via [ka] (In the formula, a is a number of 1 or more, and R 1 is an organic group having one or more carbon atoms, containing at least an alkylene and / or phenylene structure, and further containing a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.

[0161] The oxygen absorbing compound represented by formula (5) is a compound represented by formula (2) in which a=2 and R 1 For example, the isocyanate compound OCN-R 4 -NCO and hydroxyl group-containing compounds HO-R 5 The oxygen absorbing compound is a group derived from -OH and containing a structural part generated by the reaction of the two. [ka] (In the formula, f is a number equal to or greater than 0, and R 4 and R 5 Each of the above is an organic group having one or more carbon atoms, and contains at least an alkylene and / or phenylene structure, and further contains a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.

[0162] The oxygen-absorbing compound represented by formula (3) may be, for example, 1is derived from an isocyanate compound and a hydroxyl group-containing compound, contains a structural part formed by the reaction of the two, and contains hydroxyl groups as a result of residual excess hydroxyl groups or chemical modification. [ka] (In the formula, b and c are each a number equal to or greater than 1; R 2 is an organic group having one or more carbon atoms, containing at least an alkylene and / or phenylene structure, and further containing a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.

[0163] The oxygen-absorbing compound represented by formula (4) may be, for example, 1 is derived from an isocyanate compound and a hydroxyl group-containing compound, contains a structural part generated by the reaction of the two, and contains an isocyanate group as a result of residual excess isocyanate groups or chemical modification. [ka] (wherein, d and e are each a number equal to or greater than 1; R 3 is an organic group having one or more carbon atoms, containing at least an alkylene and / or phenylene structure, and further containing a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.

[0164] [Oxidation promotion catalyst] The oxidation-promoting catalyst is a compound that promotes the action of the oxygen-absorbing compound absorbing oxygen molecules and being oxidized. The oxidation-promoting catalyst may be a peroxide or a compound containing a cation made of a transition metal. A specific example of the peroxide is hydrogen peroxide.

[0165] The compound containing a cation made of a transition metal is preferably a metal soap made of a transition metal-containing compound capable of releasing a cation or complex of a transition metal atom and an anion or ligand made of a fatty acid. The transition metal is preferably cobalt, manganese, iron, nickel, copper, etc., and the anion or ligand is preferably an anion or ligand made of stearic acid, naphthenic acid, octanoic acid, acetylacetonate, etc.

[0166] As the compound containing a cation made of a transition metal, a metal soap formed by combining a cation made of one or more transition metals selected from the group consisting of the above transition metals with an anion made of one or more fatty acids selected from the group consisting of the above long-chain fatty acids can be used.Specific compounds include cobalt octylate, cobalt acetylacetone (II), cobalt acetylacetone (III), manganese acetylacetone (III), and iron acetylacetone (III).

[0167] The content of the transition metal constituting the cation in the special adhesive layer is, for example, 20 ppm or more, may be 30 ppm or more, may be 50 ppm or more, or may be 70 ppm or more. The content of the transition metal constituting the cation in the special adhesive layer is, for example, 300 ppm or less, may be 200 ppm or less, or may be 100 ppm or less. From the viewpoint of laminate strength, it is preferable that the content of the transition metal constituting the cation is not too high, for example, the content is preferably 100 ppm or less. ppm has the same meaning as μg / g. That is, ppm is a numerical value when the mass of the transition metal contained in 1 g of the special adhesive layer is expressed in μg units.

[0168] The transition metal content in the special adhesive layer is calculated by analyzing the packaging material 50 by inductively coupled plasma optical emission spectrometry (ICP-OES). ICP-OES is a method for analyzing elements in a sample based on the emission wavelength and emission intensity when electrons in atoms contained in the sample return from an excited state to a ground state. The analysis method will be described.

[0169] First, a sample of the packaging material 50 is prepared. The process of preparing the sample includes a first preparation step of preparing a solid sample and a second preparation step of preparing a liquid sample.

[0170] The first preparation step includes a collection step, a cutting step, a first heating step, and a second heating step. In the collection step, 0.5 g of the transparent or white part of the packaging material 50 is collected. The transparent part is the part of the packaging material 50 where the printed layer 45 is not provided. The white part is the part of the packaging material 50 where the white printed layer 45 is provided. In the cutting step, the collected packaging material 50 is cut into small pieces. In the first heating step, the cut packaging material 50 is placed in a crucible and roughly baked with a gas burner. In the second heating step, the special adhesive layer is heated in an electric furnace at 800°C for 120 minutes. This results in a solid sample of the ashed packaging material 50.

[0171] In the second preparation step, a liquid sample is prepared using the solid sample obtained in the first preparation step. The second preparation step includes a dissolving step, a filtering step, and an adjusting step. In the dissolving step, the solid sample is dissolved in 8 ml of nitric acid. The concentration of nitric acid is 61 mass %. In the filtering step, the nitric acid solution in which the solid sample is dissolved is filtered through a filter. As the filter, a chromatography syringe filter Millex (registered trademark)-LH 0.20 μm is used. In the adjusting step, pure water is added to the nitric acid solution filtered through the filter to obtain a 50 ml liquid sample.

[0172] The liquid sample is analyzed by ICP-OES to calculate the content of transition metals constituting cations in the packaging material 50. For example, the content of cobalt constituting cations in the packaging material 50 is calculated. The analysis by ICP-OES is performed in an environment of 25° C. and 50% RH.

[0173] The content C2 of the transition metal constituting the cation in the adhesive layer is calculated based on the content C1 of the transition metal constituting the cation in the packaging material 50. Specifically, the content C2 is calculated by dividing the content C1 by the weight ratio C3 of the adhesive layer in the packaging material 50. For example, when the content C1 is 1.1 ppm and the weight ratio C3 of the first adhesive layer 56 is 3.4% (=0.034), the content C2 of the transition metal in the first adhesive layer 56 is calculated by the following formula. C2[ppm]=C1[ppm] / C3=1.1 / 0.034=32.4

[0174] The weight ratio C3 of the first adhesive layer 56 is calculated by dividing the weight E56 of the first adhesive layer 56 per unit area by the weight E0 of the packaging material 50 per unit area. For example, 2 The weight of the first adhesive layer 56 per E56 is 3.96 x 10 -4 g and 1 cm 2 The weight of packaging material per 50 E0 is 116.5 x 10 -4 g, the weight ratio C3 of the first adhesive layer 56 is calculated by the following formula. C3 = E56 / E0 = (3.96 × 10 -4 ) / (116.5×10 -4 )=0.034

[0175] The weight E56 of the first adhesive layer 56 per unit area is calculated by multiplying the thickness T56 of the first adhesive layer 56 by the specific gravity N56 of the first adhesive layer 56. For example, when the thickness T56 of the first adhesive layer 56 is 3.6 μm=3.6×10 -4 cm, and the specific gravity N56 of the first adhesive layer 56 is 1.1 g / cm 3Then, the weight E56 of the first adhesive layer 56 is calculated by the following formula: E56[g]=T56*N56=3.96*10 -4

[0176] The weight E0 of the packaging material 50 per unit area is calculated as the sum of the products of the thickness and specific gravity of each layer of the packaging material 50. For example, the weight E0 of the packaging material 50 per unit area is calculated by the following formula. E0=T51*N51+T52*N52+T53*N53+T55*N55*T56*N56+T57*N57*T58*N58 T51: Thickness of the first stretched plastic film 51 [cm] N51: Specific gravity of the first stretched plastic film 51 [g / cm 3 〕 T52: Thickness of the second stretched plastic film 52 [cm] N52: Specific gravity of the second stretched plastic film 52 [g / cm 3 〕 T53: Thickness of the third stretched plastic film 53 [cm] N53: Specific gravity of the third stretched plastic film 53 [g / cm 3 〕 T55: Thickness of sealant film 55 [cm] N55: Specific gravity of sealant film 55 [g / cm 3 〕 T56: Thickness of the first adhesive layer 56 [cm] N56: Specific gravity of the first adhesive layer 56 [g / cm 3 〕 T57: Thickness of second adhesive layer 57 [cm] N57: Specific gravity of the second adhesive layer 57 [g / cm 3 〕 T58: Thickness of the third adhesive layer 58 [cm] N58: Specific gravity of the third adhesive layer 58 [g / cm 3 〕

[0177] In the above calculation method, it is assumed that all of the transition metals constituting the cations detected by ICP-OES are contained in the first adhesive layer 56. The specific gravity of each layer is determined based on information on the type of resin contained in each layer identified by ImagingIR.

[0178] In ImagingIR, infrared spectroscopy is performed on each layer appearing in a cross section of a test piece of the packaging material 50. Based on a chart obtained by infrared spectroscopy, information regarding the type of resin contained in each layer is obtained.

[0179] The ImagingIR test piece is obtained by cutting out a part of the packaging material 50. The test piece is cut using a sliding microtome at room temperature (23° C.). This results in a smooth cross section of the test piece. The smooth cross section of the test piece is measured under the following conditions using the following Fourier transform infrared spectroscopy (FT-IR) device. FT-IR instrument: Agilent Technologies Cary 670 FTIR FT-IR microscope: Agilent Technologies Cary 620 FTIR ·Measurement area: 70μm×70μm Detector pixel count: 64×64 Wavelength range: 900cm -1 ~4000cm -1 Accumulation: 32 times Mode: ATR

[0180] The above-mentioned normal adhesive layer may be specified based on the content of transition metals constituting the cations. For example, an adhesive layer having a content of transition metals constituting the cations of less than 20 ppm may be specified as a normal adhesive layer.

[0181] A transition metal may be contained in a layer of the packaging material 50 other than the special adhesive layer. Depending on the type of transition metal, it may be determined whether the transition metal detected by ICP-OES is the transition metal contained in the special adhesive layer. For example, if the transition metal detected by ICP-OES is cobalt, manganese, nickel, or copper, it may be determined that the special adhesive layer contains these transition metals.

[0182] [Denaturant] The modifier is a compound containing a functional group that reacts with the oxygen absorbing compound when the oxygen absorbing compound contains a functional group, and various reactive monomers and resins can be used. By including a modifier in the oxygen absorbing adhesive composition, it is possible to bond the oxygen absorbing compound to other components in the oxygen absorbing adhesive composition, adjust the content of the oxygen absorbing compound in the oxygen absorbing adhesive composition, and adjust the hardness of the cured product of the oxygen absorbing adhesive composition.

[0183] For example, when the oxygen absorbing compound contains a hydroxyl group or an isocyanate group, a modifier consisting of an isocyanate-based compound and / or a hydroxyl group-containing compound can be used. When the oxygen absorbing adhesive composition is a urethane-based composition, the equivalent ratio NCO / OH of the oxygen absorbing adhesive composition is preferably 0.5 or more and 8 or less. If it is less than the above range, the curing of the oxygen absorbing adhesive composition may be insufficient, and sufficient lamination strength (adhesive strength) may not be obtained. If it is greater than the above range, the pot life of the oxygen absorbing adhesive composition may be too short.

[0184] (Isocyanate compounds for use as modifiers) The isocyanate compound for the modifier can be the isocyanate compound used in the synthesis of the oxygen absorbing compound, and any of aromatic isocyanates, aliphatic isocyanates, and urethane chain-extended isocyanates thereof can be used. In addition, in order for the oxygen absorbing adhesive composition to harden, it is preferable to use one that contains two or more isocyanate groups in one molecule. However, it is also possible to use an isocyanate compound that contains one isocyanate group in one molecule in combination within a range that does not inhibit the sufficient effect of the oxygen absorbing adhesive composition. As an isocyanate compound that contains two or more isocyanate groups in one molecule, a biuret form of hexamethylene diisocyanate is particularly preferable.

[0185] Specific examples of isocyanate compounds include tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, norbornane diisocyanate, xylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, phenylene diisocyanate, diphenylether diisocyanate, polymethylene polyphenyl polyisocyanate, and their trimethylolpropane adducts, biuret compounds, allophanate compounds, isocyanurate compounds (trimers), and various derivatives thereof. Among these, the biuret compounds of toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate are preferred.

[0186] (Hydroxyl-containing compounds for use as modifiers) The hydroxyl group-containing compound for the modifier can be the hydroxyl group-containing compound used in the synthesis of the oxygen absorbing compound, and any of aromatic hydroxyl group-containing compounds, aliphatic hydroxyl group-containing compounds, and urethane chain-extended polyols thereof can be used. In order for the oxygen absorbing adhesive composition to harden, it is preferable to use one containing two or more hydroxyl groups in one molecule. However, a hydroxyl group-containing compound containing one hydroxyl group in one molecule can also be used in combination within a range that does not inhibit the sufficient effect of the oxygen absorbing adhesive composition. As the hydroxyl group-containing compound containing two or more hydroxyl groups in one molecule, any of aromatic hydroxyl group-containing compounds and aliphatic hydroxyl group-containing compounds can be used, and they may be alcohol-based or phenol-based. As the isocyanate-based compound containing two or more isocyanate groups in one molecule, polyalkylene ether diol and urethane chain-extended polyol of polyalkylene ether diol are particularly preferred.

[0187] [Dilution solvent] The dilution solvent is not particularly limited as long as it can uniformly dissolve or disperse the oxygen absorbing compound and the oxidation-promoting catalyst, the oxygen absorbing adhesive composition can be uniform, and it is suitable for the dry lamination process, and for example, an ester-based dilution solvent, a ketone-based dilution solvent, a hydrocarbon-based dilution solvent, etc. can be used. Specific examples of ester-based dilution solvents include ethyl acetate and butyl acetate, etc., specific examples of ketone-based dilution solvents include methyl ethyl ketone, etc., and specific examples of hydrocarbon-based dilution solvents include toluene, etc. Among these, ethyl acetate is easy to use and is preferred.

[0188] [Various additives] The oxygen-absorbing adhesive composition may contain various additives as necessary, such as a curing accelerator, a curing regulator for extending the pot life, an antioxidant for suppressing a decrease in oxygen absorption during storage or use of the oxygen-absorbing adhesive composition or before the content is placed in a package, an adhesive assistant, a tackifier, a leveling agent, an ultraviolet absorber, an antifoaming agent, a coloring pigment, or an extender pigment.

[0189] (Cure accelerator) The curing accelerator can be used without any particular limitation as long as it accelerates the curing reaction of the oxygen absorbing adhesive composition.Specific curing accelerators include metal-containing compounds such as dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dibutyltin dimaleate, tetrabutyl titanate, and tetraisopropyl titanate, and tertiary amines such as 1,8-diaza-bicyclo(5,4,0)undecene-7, 1,5-diaza-bicyclo(4,3,0)nonene-5, and triethanolamine, and one or more selected from the group consisting of these can be used.

[0190] (hardening regulator) When the pot life of the oxygen absorbing adhesive composition is shortened due to an oxidation-promoting catalyst, the pot life can be extended by using a curing regulator in combination. Specific curing regulators are preferably phosphoric acids, such as orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and their ester derivatives, and one or more selected from the group consisting of these can be used. The amount of reaction regulator added is preferably 200 ppm or more and 400 ppm or less relative to the resin component of the oxygen absorbing adhesive composition. If the amount is less than the above range, it is difficult to obtain the effect of extending the pot life, and if the amount is more than the above range, there is a risk of inhibiting the curing of the oxygen absorbing adhesive composition.

[0191] (Antioxidants) The oxygen absorbing adhesive composition may contain an antioxidant to suppress deterioration of oxygen absorbing properties during storage or use of the oxygen absorbing adhesive composition, and further in a process before a package made using the oxygen absorbing adhesive composition contains contents, and to maintain high oxygen absorbing properties after the contents are contained. Specific examples of antioxidants include phenols, lactones, thioethers, gallic acid, ascorbic acid, erythorbic acid, catechin, dibutylhydroxytoluene, tocopherol, citric acid, butylhydroxyanisole, phosphorous acid ester, hindered amine, aromatic amines, and the like, and one or more selected from the group consisting of these can be used. In addition, when heat or light is assumed to be used as a trigger for the expression of oxygen absorbing properties, it is preferable to use an antioxidant with low heat resistance and light resistance, such as ascorbic acid or tocopherol, and it is not preferable to use an antioxidant with high heat resistance and light resistance, such as a phenolic antioxidant. The amount of antioxidant added is preferably 10 ppm or more and 10,000 ppm or less relative to the oxygen absorbing compound. If the amount is less than the above range, the antioxidant effect is likely to be insufficient, whereas if the amount is more than the above range, there is a risk that the oxygen absorbing ability will decrease.

[0192] The above-mentioned antioxidants may be included in the sealant film 55 described above.

[0193] (Adhesive assistant) Silane coupling agent is preferable as the adhesion aid for supporting the adhesive force.Silane coupling agent includes γ-glycidoxypropyltrialkoxysilane, γ-methacryloxypropyltrialkoxysilane, γ-glycidoxypropylmethyldialkoxysilane, β-(3,4-epoxycyclohexyl)ethyltrialkoxysilane, γ-aminopropyltrialkoxysilane, γ-aminopropylmethyldialkoxysilane, N-(β-aminoethyl)-γ-aminopropyltrialkoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldialkoxysilane, N-butyl-3-amino-2-methylpropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, γ-mercaptopropylmethyldialkoxysilane, and alkoxy group is preferably methoxy group or ethoxy group, and one or more selected from the group consisting of these can be used.

[0194] (tackifier) Examples of the tackifier include paraffin wax, polyethylene wax, rosin, rosin glycerin ester, terpene, and alkylphenol. One or more types selected from the group consisting of these can be used.

[0195] (Leveling agent) The leveling agent may be an acrylic polymer-based agent, a modified silicone-based agent, an acetylene diol-based agent, or the like. One or more types selected from the group consisting of these may be used.

[0196] (UV absorber) Examples of the ultraviolet absorbing agent include benzotriazole-based, hydroxyphenyltriazine-based, and hindered amine-based agents, and one or more types selected from the group consisting of these may be used.

[0197] (Antifoaming agent) The antifoaming agent may be a surfactant, polyether-modified silicone oil, or the like, and one or more selected from the group consisting of these may be used.

[0198] (Color pigments) Examples of color pigments include organic pigments such as anthraquinone, diketopyrrolopyrrole, perylene maroon, carbon black, dioxazine, perylene, benzimidazolone, isoindolinone, isoindoline, phthalocyanine, and indanthrene, and inorganic pigments such as yellow iron oxide, red iron oxide, azomethine copper complex, titanium oxide, and silicon oxide. One or more types selected from the group consisting of these can be used.

[0199] (Extender pigment) The extender pigment is a white or colorless pigment used as an extender or as an adjuster for coloring power, gloss, strength, usability, etc. Specific examples include inorganic pigments such as barium sulfate, barium carbonate, calcium carbonate, magnesium oxide, magnesium carbonate, magnesium hydroxide, barium titanate, calcium hydroxide, calcium sulfite, calcium sulfate, calcium oxide, calcium silicate, titanium oxide, silica, zeolite, and talc, and one or more types selected from the group consisting of these can be used.

[0200] <<Method for preparing oxygen-absorbing adhesive composition>> The oxygen absorbing adhesive composition can be produced by mixing all the components such as the oxygen absorbing compound, the oxidation promoting catalyst, and, if necessary, further modifiers, diluting solvents, and various additives. Alternatively, the oxygen absorbing compound, the oxidation promoting catalyst, and, if necessary, further modifiers, diluting solvents, and various additives can be mixed with an existing adhesive composition. The method of performing the above mixing and the order of mixing the components are not particularly limited, and the method and mixing order used in preparing a general adhesive composition can be applied. Specific mixing methods include a method of dissolving in a solvent and mixing, and a method of melt kneading. At this time, it is preferable to adjust the heating temperature to increase solubility and dispersibility.

[0201] <<Method of using the oxygen-absorbing adhesive composition>> There is no particular limitation on the method of using the oxygen-absorbing adhesive composition, and it can be used in a general adhesive manner. For example, it can be used in a non-solvent lamination method in which it is heated to a suitable viscosity, or in a dry lamination method in which it is used by adding a dilution solvent or other compounded adhesive to adjust the coating viscosity to a suitable level. When forming an adhesive layer using the oxygen-absorbing adhesive composition, the coating amount is 2.0 g / m 2 ~5.0g / m 2 is preferred, and 3.0 g / m 2 ~5.0g / m 2 If the amount is less than the above range, sufficient oxygen absorbency may not be obtained, whereas if the amount is more than the above range, the oxygen absorbency does not change significantly, leading to a cost disadvantage, which is not preferable.

[0202] <Manufacturing methods for packaging materials> Next, an example of a method for producing the packaging material 50 will be described.

[0203] First, the above-mentioned first stretched plastic film 51 and second stretched plastic film 52 are prepared. The first stretched plastic film 51 may be provided with a transparent deposition layer 62. A gas barrier coating film 63 may be provided on the surface of the transparent deposition layer 62. A printed layer 61 may be provided on the surface of the gas barrier coating film 63. Next, the first stretched plastic film 51 and the second stretched plastic film 52 are laminated via the first adhesive layer 56 by a dry lamination method. The first adhesive layer 56 may be a normal adhesive layer.

[0204] Next, the laminate including the first stretched plastic film 51 and the second stretched plastic film 52 and the third stretched plastic film 53 are laminated via the second adhesive layer 57 by a dry lamination method. The second adhesive layer 57 may be a special adhesive layer. That is, the laminate including the first stretched plastic film 51 and the second stretched plastic film 52 and the third stretched plastic film 53 may be dry laminated using an oxygen-absorbing adhesive composition.

[0205] Thereafter, the laminate including the first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53 is laminated with the sealant film 55 via the third adhesive layer 58. This makes it possible to obtain a packaging material 50 including the first stretched plastic film 51, the second stretched plastic film 52, the third stretched plastic film 53, and the sealant film 55. The third adhesive layer 58 may be a normal adhesive layer.

[0206] The order in which the first stretched plastic film 51, the second stretched plastic film 52, the third stretched plastic film 53, and the sealant film 55 are laminated by the dry lamination method is not limited to the above-mentioned order. For example, the packaging material 50 may be produced by laminating a first laminate including the first stretched plastic film 51 and the second stretched plastic film 52 and a second laminate including the third stretched plastic film 53 and the sealant film 55 by the dry lamination method.

[0207] In the dry lamination method, an adhesive composition is first applied to one of the two films to be laminated. The applied adhesive composition is then dried to volatilize the solvent. The two films are then laminated together via the dried adhesive composition.

[0208] The packaging material 50 may be aged at 20° C. or higher and 50° C. or lower for 2 days or more and 5 days or less. When the packaging material 50 has a special adhesive layer, it is preferable to age the packaging material 50 at as low a temperature as possible or in an inert gas atmosphere so as not to reduce the oxygen absorption of the packaging material 50. When storing the produced packaging material 50, it is preferable to store the packaging material 50 at 10° C. or lower or in an inert gas atmosphere so as not to reduce the oxygen absorption of the packaging material 50.

[0209] The packaging material 50 may be subjected to secondary processing in order to impart surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubrication functions, optical functions, thermal functions, and biocompatibility. Examples of secondary processing include embossing, painting, bonding, printing, metallizing (plating, etc.), machining, and surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.). The packaging material 50 may also be subjected to lamination (dry lamination or extrusion lamination), pouching, and other post-treatment processes to produce molded products.

[0210] <Pouch> The packaging material 50 may be used as a material for forming a pouch. Fig. 4 is a front view showing an example of a pouch 10 including the packaging material 50. The pouch 10 includes a storage section 18 for storing contents. Note that Fig. 4 shows the pouch 10 in a state in which no contents are stored. The configuration of the pouch 10 will be described below.

[0211] 4, pouch 10 includes upper portion 11, lower portion 12, first side portion 13 and second side portion 14, and has a generally rectangular outline in a front view. Names such as "upper portion," "lower portion," and "side portion," as well as terms such as "upper" and "lower portion," merely represent the relative positions and directions of pouch 10 and its components when the lower portion is defined as the side that can be located below when pouch 10 is heated. The position of pouch 10 is not limited by the names and terms used in this specification.

[0212] The pouch 10 includes a surface film 15 that constitutes the surface of the pouch 10, and a back film 16 that constitutes the back surface of the pouch 10. Each film may be made of the packaging material 50 described above.

[0213] The terms "front film" and "back film" are merely used to divide each film according to their positional relationship, and the above terms do not limit the method of providing the films when manufacturing the pouch 10. For example, the pouch 10 may be manufactured using one film in which the front film 15 and the back film 16 are continuously provided, or may be manufactured using a total of two films, one front film 15 and one back film 16.

[0214] The inner surfaces of the front film 15 and the back film 16 are joined together by a seal portion. In a plan view of the pouch 10 such as Fig. 4, the seal portion is hatched. The space surrounded by the seal portion, the front film 15, and the back film 16 can function as a storage portion 18 for storing contents.

[0215] As long as the opposing films can be joined together, the method for forming the seal portion is not particularly limited. For example, the seal portion may be formed by melting the inner surfaces of the films by heating or the like and fusing the inner surfaces together, i.e., by heat sealing. Alternatively, the seal portion may be formed by bonding the inner surfaces of the opposing films together using an adhesive or the like.

[0216] As shown in FIG. 4, the sealed portion of the pouch 10 has a first side sealed portion 30, a second side sealed portion 35, and an upper sealed portion 11a. The first side sealed portion 30 is located on the first side 13. The second side sealed portion 35 is located on the second side 14. The second side 14 faces the first side 13 in the first direction D1. The upper sealed portion 11a is located on the upper portion 11. The upper sealed portion 11a is connected to the first side sealed portion 30 and the second side sealed portion 35. The non-sealed portion surrounded by the first side sealed portion 30, the second side sealed portion 35, and the upper sealed portion 11a functions as a storage portion 18 that stores the contents.

[0217] In pouch 10 before it is filled with the contents (when no contents are contained therein), lower portion 12 of pouch 10 forms opening 12b, as shown in Fig. 4. After the contents are contained in pouch 10, the inner surface of front film 15 and the inner surface of back film 16 are joined at lower portion 12 to form a lower seal portion and seal pouch 10.

[0218] The first side seal portion 30, the second side seal portion 35, the upper seal portion 11a and the lower seal portion are seal portions formed by joining the inner surface of the front film 15 and the inner surface of the back film 16 together.

[0219] In addition to the unsealed portion that functions as the storage portion 18, the pouch 10 has a first unsealed portion 40 that is isolated from the storage portion 18 by a first side sealed portion 30, as shown in FIG. 4. The unsealed portion is a portion where a film exists in which opposing inner surfaces are not joined to each other. The first unsealed portion 40 is located closer to the upper portion 11 of the pouch 10. "More towards the upper portion 11" means that the first unsealed portion 40 is located on the upper portion 11 side of the center point C of the storage portion 18.

[0220] 4, the first non-sealed portion 40 expands to reach the first side edge 13x of the first side portion 13 of the pouch 10. In other words, the first non-sealed portion 40 overlaps the first side edge 13x and has an opening edge portion 41 that opens to the outside. Steam that is generated in the storage portion 18 and flows into the first non-sealed portion 40 can be discharged to the outside from the opening edge portion 41.

[0221] The first side seal portion 30 is configured to define a first non-sealed portion 40. For example, as shown in FIG. 4, the first side seal portion 30 has an upper seal portion 31, a lower seal portion 32, and an intermediate seal portion 33. In the example shown in FIG. 4, the upper seal portion 31 extends along the first side portion 13 from the first non-sealed portion 40 toward the top portion 11 of the pouch 10. The lower seal portion 32 extends along the first side portion 13 from the first non-sealed portion 40 toward the bottom portion 12 of the pouch 10. The intermediate seal portion 33 is located between the containing portion 18 and the first non-sealed portion 40. The intermediate seal portion 33 includes a first end connected to the upper seal portion 31 and a second end connected to the lower seal portion 32.

[0222] When pouch 10 is heated and steam is generated in storage section 18, increasing the pressure in storage section 18, intermediate sealed portion 33 partially peels off, connecting storage section 18 to first non-sealed section 40. Steam that flows from storage section 18 into first non-sealed section 40 can be discharged to the outside from opening edge section 41. In this way, intermediate sealed portion 33 and first non-sealed section 40 function as a steam vent mechanism that discharges steam from storage section 18 to the outside.

[0223] As shown in FIG. 4, the pouch 10 may include an opening means 30c located in the upper sealed portion 31. The opening means 30c penetrates the front film 15 and the back film 16. The opening means 30c may be a notch, a cut, or the like. The opening means 30c can be a starting point for a user to tear the pouch 10. The opening means 30c extends from the first side edge 13x toward the containing portion 18. The opening means 30c may be located between the first non-sealed portion 40 and the upper portion 11 in the second direction D2.

[0224] As shown in FIG. 4, the pouch 10 may include an opening means 35c located at the second side seal portion 35. The opening means 35c penetrates the front film 15 and the back film 16. The opening means 35c may be a notch, a cut, or the like. Like the opening means 30c, the opening means 35c can be a starting point when a user tears the pouch 10. The opening means 35c extends from the second side edge 14x toward the containing portion 18. The opening means 35c may be formed in a portion of the second side seal portion 35 facing the opening means 30c in the first direction D1.

[0225] The pouch 10 may include a second unsealed portion 45 located at the second side edge 14x. The second unsealed portion 45 is separated from the container portion 18 by the second side seal portion 35. The second unsealed portion 45 may face the first unsealed portion 40 in the first direction D1. The second unsealed portion 45 may be in the same position as the first unsealed portion 40 in the first direction D1.

[0226] The second side seal portion 35 may include an upper seal portion 36, a lower seal portion 37, and an intermediate seal portion 38. The upper seal portion 36 extends from the second non-sealed portion 45 toward the upper portion 11 along the second side edge 14x. The lower seal portion 37 extends from the second non-sealed portion 45 toward the lower portion 12 along the second side edge 14x. The intermediate seal portion 38 is located between the accommodation portion 18 and the second non-sealed portion 45. The intermediate seal portion 38 includes a first end connected to the upper seal portion 36 and a second end connected to the lower seal portion 37.

[0227] 5 is a diagram showing pouch 10 in a state in which the contents are contained and upper portion 11 is sealed. After the contents are filled into pouch 10 through opening 11b of upper portion 11, the inner surface of front film 15 and the inner surface of back film 16 are joined at upper portion 11. This forms upper seal portion 11a and seals pouch 10.

[0228] 5, an imaginary straight line L1 is a straight line that connects the center point C of the storage section 18 and the first unsealed portion 40 at the shortest distance. An extension line of the imaginary straight line L1 may intersect with the opening edge portion 41.

[0229] The distance H1 in the first direction D1 from the center point C to the inner edge of the first side seal portion 30 is equal to the distance H2 in the first direction D1 from the center point C to the inner edge of the second side seal portion 35. The distance H2 in the second direction D2 from the center point C to the inner edge of the upper seal portion 11a is equal to the distance H4 in the second direction D2 from the center point C to the inner edge of the lower seal portion 12a.

[0230] The symbol H5 represents the distance from the center point C to the intermediate seal portion 33. The distance H5 is the distance from the intersection of the virtual straight line L1 and the inner edge 33a of the intermediate seal portion 33 to the center point C. The distance H5 may be smaller than the distance H3, or may be larger than the distance H3. The ratio of the distance H5 to the distance H3, H5 / H3, is, for example, 0.95 or more, 0.98 or more, more than 1.00, 1.01 or more, 1.03 or more, or 1.05 or more. H5 / H3 is, for example, 1.10 or less, 1.05 or less, less than 1.00, or 0.98 or less.

[0231] The symbol H6 represents the distance from the center point C to the first unsealed portion 40. The distance H6 is the distance from the intersection of the imaginary straight line L1 and the outer edge of the intermediate seal portion 33 to the center point C.

[0232] In the pouch 10 of the type shown in FIGS. 4 and 5, the area of ​​the storage section 18 in a plan view is, for example, 700 cm 2 Less than or equal to 500cm 2 By setting an upper limit on the area of ​​the storage section 18, the oxygen concentration in the storage section 18 can be appropriately reduced by the function of the special adhesive layer. The area of ​​the storage section 18 in a plan view may be, for example, 240 cm. 2 Above 280cm 2 It may be more than that.

[0233] The contents contained in the pouch 10 are heated by a microwave oven. The contents may include ingredients and liquid ingredients. The ingredients may include ingredients containing oil such as meat. The contents may be cooked foods. Examples of cooked foods include sauces such as curry, soup, and pasta, minced meat dishes such as hamburger steaks and meatballs, Chinese dishes such as sweet and sour pork, Western dishes such as tomato stew and cream stew, Japanese dishes such as stewed offal, and ethnic dishes.

[0234] The weight of the contents contained in the pouch 10 is, for example, 50 g or more, may be 100 g or more, or may be 130 g or more. The weight of the contents contained in the pouch 10 is, for example, 300 g or less, may be 250 g or less, or may be 200 g or less.

[0235] The ratio of the weight of the ingredients to the weight of the entire contents is, for example, 1% or more, may be 5% or more, or may be 10% or more. The ratio of the weight of the ingredients to the weight of the entire contents is, for example, 95% or less, may be 90% or less, or may be 70% or less. The ingredients are obtained by removing liquid components from the contents. For example, the ingredients can be obtained by straining the liquid components in the contents using a sieve. The mesh of the sieve is, for example, 0.7 mm.

[0236] [How to heat the pouch] Next, a method for heating the above-mentioned pouch 10 will be described. First, the pouch 10 is placed in a microwave oven with the upper portion 11 positioned higher than the lower portion 12. For example, a box tilted relative to the horizontal direction is placed in the microwave oven, and the pouch 10 is placed in the box. Next, the pouch 10 is heated using the microwave oven. The moisture contained in the contents evaporates, increasing the pressure in the storage section 18.

[0237] When the pressure in the storage section 18 increases, the pouch 10 expands, for example, in a circular shape around the center point C of the storage section 18. Therefore, a force is applied to each position of the sealed section in a direction from the center point C toward the sealed section. When a force is applied to the intermediate sealed section 33, peeling of the intermediate sealed section 33 progresses. When the peeling of the intermediate sealed section 33 reaches the first non-sealed section 40, a flow path is formed in the intermediate sealed section 33. Steam generated in the storage section 18 flows into the first non-sealed section 40 through the flow path and is released to the outside from the opening edge section 41. This makes it possible to suppress an increase in pressure in the storage section 18.

[0238] When the contents are heated using a microwave oven, the temperatures of the front film 15 and the back film 16 of the pouch 10 also rise. For example, while the contents are heated using a microwave oven, the contents may splash and adhere to the inner surface of the front film 15. When the contents adhered to the inner surface are further heated, the temperature of the inner surface of the front film 15 in contact with the contents also rises. The heat resistance of the sealant film 55 constituting the inner surface of the front film 15 is lower than that of the stretched plastic film. For this reason, it is considered that a part of the sealant film 55 constituting the front film 15 is deformed by the influence of heat. If the influence of the deformation of the sealant film 55 extends to the outer surface of the front film 15, it is considered that holes may be made in the front film 15 or wrinkles may be formed in the front film 15.

[0239] In this embodiment, the sealant film 55 contains block polypropylene. The packaging material 50 includes three stretched polyester films, namely, a first stretched plastic film 51, a second stretched plastic film 52, and a third stretched plastic film 53. This makes it possible to suppress deformation of the packaging material 50 due to the influence of heat. This makes it possible to suppress the occurrence of holes in the surface film 15 and the formation of wrinkles in the surface film 15.

[0240] In the present embodiment, the sealant film 55 contains polyethylene in addition to block polypropylene. This increases the drop strength of the pouch 10. This prevents the pouch 10 from breaking due to the impact of being dropped.

[0241] In the present embodiment, the packaging material 50 includes a special adhesive layer located inside the barrier layer 64. This makes it possible to prevent the contents contained in the pouch 10 made of the packaging material 50 from being oxidized.

[0242] In this way, according to this embodiment, the heat resistance, drop strength, and oxygen absorption performance of the packaging material 50 can be improved.

[0243] Various modifications can be made to the above-described embodiment. Below, the modified example will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment will be used for parts that can be configured similarly to the above-described embodiment, and duplicated descriptions will be omitted. In addition, if it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified example, the description may be omitted.

[0244] (Modified Pouch) FIG. 6 is a front view showing a modified example of the pouch 10. In the above embodiment, an example has been shown in which the first non-sealed portion 40, which is isolated from the storage portion 18 by the intermediate seal portion 33, expands to reach the first side edge 13x. As long as the steam in the storage portion 18 can be discharged to the outside of the pouch 10, the configurations of the first side seal portion 30 and the first non-sealed portion 40 are not limited. For example, as shown in FIG. 6, the first non-sealed portion 40 may not be in contact with the first side edge 13x. For example, the first side seal portion 30 may include a second intermediate seal portion 34 located between the first non-sealed portion 40 and the first side edge 13x. The pouch 10 may include a through hole 42 formed in the first non-sealed portion 40. The through hole 42 penetrates at least one of the front film 15 or the back film 16.

[0245] 6, when the sealed pouch 10 is heated, peeling of the intermediate sealed portion 33 progresses. When the peeling of the intermediate sealed portion 33 reaches the first non-sealed portion 40, steam generated in the containing portion 18 flows into the first non-sealed portion 40, and the steam is discharged to the outside of the pouch 10 through the through-hole 42. This makes it possible to suppress an increase in pressure in the containing portion 18.

[0246] In the pouch 10 of the type shown in FIG. 6, the area of ​​the storage section 18 in a plan view is, for example, 700 cm 2 Less than or equal to 500cm 2 The area of ​​the storage section 18 in a plan view may be, for example, 240 cm 2 Above 280cm 2 It may be more than that.

[0247] (Modified Pouch) Fig. 7 is a front view showing one modified example of the pouch 10. The pouch 10 shown in Fig. 7 differs from the pouch 10 shown in Fig. 4 in that it includes a lower film 17. The pouch 10 shown in Fig. 7 is a gusset-type pouch configured to be self-supporting. The lower film 17 is disposed between the front film 15 and the back film 16 in a state where it is folded back at the fold-back portion 17f. In this case, the lower seal portion 12a includes a seal portion configured by joining the inner surface of the front film 15 and the inner surface of the lower film 17, and a seal portion configured by joining the inner surface of the back film 16 and the inner surface of the lower film 17.

[0248] 7, an opening 11b may be formed in an upper portion 11 of the pouch 10. After the contents are placed in the pouch 10, the inner surface of the front film 15 and the inner surface of the back film 16 are joined at the upper portion 11 to form an upper seal portion and seal the pouch 10.

[0249] In the pouch 10 of the type shown in FIG. 7, the area of ​​the storage section 18 in a plan view is, for example, 700 cm 2 Less than or equal to 500cm 2 The area of ​​the storage section 18 in a plan view may be, for example, 240 cm 2 Above 280cm 2 It may be more than that.

[0250] In the pouch 10 of the type shown in FIG. 7, the area of ​​the lower portion 12 is, for example, 120 cm 2 Less than or equal to 100cm 2 The area of ​​the lower portion 12 may be, for example, 30 cm 2 More than 50cm 2 The area of ​​the lower portion 12 is calculated by subtracting the area of ​​the lower seal portion from the area of ​​the lower film 17.

[0251] (Modified Pouch) 8 is a front view showing one modified example of the pouch 10. The surface film 15 may include a joint portion 20 in which the inner surfaces of the surface films 15 are partially overlapped. The joint portion 20 may be formed, for example, by folding back one sheet of surface film 15 at a base portion 201 to form folds. The joint portion 20 may also be formed by overlapping portions of two sheets of surface films 15.

[0252] The joint portion 20 includes a joint seal portion 21 in which the inner surfaces of the surface film 15 are joined together. The joint seal portion 21 includes a tip seal portion 21a extending along the tip portion 202 of the joint portion 20 from the first side portion 13 to the second side portion 14. The joint seal portion 21 may further include a steam release seal portion 21b protruding from the tip seal portion 21a toward the base portion 201. The joint portion 20 may include a non-sealed portion 23 that is isolated from the storage portion 18 by the steam release seal portion 21b. The steam release seal portion 21b and the non-sealed portion 23 may be located in the center of the joint portion 20 in the first direction D1. The joint portion 20 may include a through hole 22 that penetrates the surface film 15 in the non-sealed portion 23.

[0253] 8, when the sealed pouch 10 is heated, peeling of the steam release sealed portion 21b progresses. When the peeling of the steam release sealed portion 21b reaches the non-sealed portion 23, steam generated in the containing portion 18 flows into the non-sealed portion 23 and is discharged to the outside of the pouch 10 through the through hole 22. This makes it possible to suppress an increase in pressure in the containing portion 18.

[0254] In the pouch 10 of the type shown in FIG. 8, the area of ​​the storage section 18 in a plan view is, for example, 700 cm 2 Less than or equal to 500cm 2 The area of ​​the storage section 18 in a plan view may be, for example, 240 cm 2 Above 280cm 2 It may be more than that.

[0255] (Modification of Barrier Layer) In the above-described embodiment, an example has been shown in which the transparent deposition layer 62 is provided on the first stretched plastic film 51 or the second stretched plastic film 52. The transparent deposition layer 62 may be supported by a plastic film other than the first stretched plastic film 51 or the second stretched plastic film 52. For example, the barrier layer 64 may include a support film other than the first stretched plastic film 51 or the second stretched plastic film 52, and the transparent deposition layer 62 formed on the surface of the support film. Examples of materials constituting the support film include polyester, polyamide, polyolefin, etc.

[0256] (Modification of Barrier Layer) In the above-described embodiment, an example has been shown in which the barrier layer 64 includes the transparent vapor deposition layer 62. The specific configuration of the barrier layer 64 is not limited as long as it can prevent gases such as oxygen and water vapor from entering the containing section 18 from the outside of the pouch 10. For example, the barrier layer 64 may be a resin coating film or a resin film provided on the first stretched plastic film 51 or the second stretched plastic film 52.

[0257] The resin coating film and the resin film contain a barrier resin, which may be an oxygen barrier resin having a low oxygen permeability.

[0258] The barrier resin includes a resin having excellent gas barrier properties. Examples of the resin having excellent gas barrier properties include polyvinylidene chloride resin (PVDC), polyester resin, polyamide resin, ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, etc. The polyamide resin is, for example, an aromatic polyamide such as nylon MXD6. The ethylene-vinyl alcohol copolymer is obtained, for example, by completely saponifying an ethylene-vinyl acetate copolymer having a content of 79% by mass or more and 92% by mass or less. The ethylene content in the ethylene-vinyl alcohol copolymer is, for example, 25 mol % or more and 50 mol % or less. EXAMPLES

[0259] Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples as long as it does not depart from the gist of the present invention.

[0260] Example 1 A first stretched plastic film 51 made of a biaxially stretched PET film with a thickness of 12 μm was prepared. Then, a transparent deposition layer 62 made of aluminum oxide was formed on the inner surface of the first stretched plastic film 51. Then, ink was applied onto the transparent deposition layer 62 by gravure printing. By drying the ink, a printed layer 61 was formed on the transparent deposition layer 62. As the ink, Rio Alpha R631 white manufactured by Toyo Ink Co., Ltd. was used. The thickness of the printed layer 61 after drying was 1 μm.

[0261] A second stretched plastic film 52 made of a biaxially stretched PET film having a thickness of 12 μm was prepared. E5102 manufactured by Toyobo Co., Ltd. was used as the biaxially stretched PET film. Next, the first stretched plastic film 51 and the second stretched plastic film 52 were bonded together via a first adhesive layer 56. Specifically, an adhesive composition not containing an oxygen absorbing compound was applied onto the printed layer 61 on the first stretched plastic film 51, the adhesive composition was dried, and then the second stretched plastic film 52 was laminated onto the adhesive composition. The first adhesive layer 56 was a normal adhesive layer. The thickness of the first adhesive layer 56 after drying was 3.6 μm.

[0262] Next, a third stretched plastic film 53 consisting of a biaxially stretched PET film having a thickness of 12 μm was prepared. E5102 manufactured by Toyobo Co., Ltd. was used as the biaxially stretched PET film. Next, a laminate including the first stretched plastic film 51 and the second stretched plastic film 52 and the third stretched plastic film 53 were bonded together via the second adhesive layer 57. Specifically, an oxygen-absorbing adhesive composition was applied onto the second stretched plastic film 52, the adhesive composition was dried, and then the third stretched plastic film 53 was laminated onto the adhesive composition. The second adhesive layer 57 was a special adhesive layer. The thickness of the second adhesive layer 57 after drying was 3.6 μm.

[0263] Next, a sealant film 55 having a thickness of 60 μm and made of the above-mentioned first type of unstretched polypropylene film was prepared. Next, a laminate including the first stretched plastic film 51, the second stretched plastic film 52, and the third stretched plastic film 53 was bonded to the sealant film 55 via the third adhesive layer 58. Specifically, an adhesive composition not including an oxygen absorbing compound was applied onto the third stretched plastic film 53, the adhesive composition was dried, and then the sealant film 55 was laminated onto the adhesive composition. The third adhesive layer 58 was a normal adhesive layer. The thickness of the third adhesive layer 58 after drying was 3.6 μm. In this way, the packaging material 50 was produced. After this, the packaging material 50 was aged for three days in an environment of 40° C.

[0264] The layer structure of the packaging material 50 of Example 1 is expressed as follows. PET(12) / Metal deposition / Printing(1) / AD(3.6) / PET(12) / Special AD(3.6) / PET(12) / AD(3.6) / CPP1(60) "PET" means biaxially oriented PET film. "Vapor deposition" means transparent vapor deposition layer. "Mark" means printed layer. "AD" means normal adhesive layer. "Special AD" means special adhesive layer. "CPP1" means first type unoriented polypropylene film. The numbers in parentheses mean the thickness of the layer. The unit of thickness is μm. The thickness was calculated by observing the cross section of the sample of the packaging material 50 using a scanning electron microscope. The scanning electron microscope used was SU8000 manufactured by Hitachi, Ltd.

[0265] [Measurement 1 Catalyst concentration] The second adhesive layer 57 of the packaging material 50 was analyzed by ICP-OES. The device used for ICP-OES was an ICPE-9820 manufactured by Shimadzu Corporation. The measurement atmosphere was 25° C. and 50% RH.

[0266] The instrument conditions were as follows: RF-Power: 1200 Carrier gas: Argon Carrier gas flow rate: 0.7L / min Nebulizer: Borosilicate glass nebulizer Torch: Quartz Torch Autosampler: ASC-9800

[0267] The analysis results of the second adhesive layer 57 by ICP-OES are shown in FIG. 10. The horizontal and vertical axes of the graph in FIG. 10 indicate the emission wavelength and the emission intensity. The transition metal content in the second adhesive layer 57 is calculated based on the area of ​​the emission intensity peak. The transition metal content in the second adhesive layer 57 was 35 ppm. The transition metal was cobalt.

[0268] [Evaluation 1: Oxygen absorption] The pouch 10 in Fig. 4 was produced using the packaging material 50 as the front film 1 and the back film 2. Next, an oxygen sensor chip and 180 mL of pure water were placed in the storage section 18 of the pouch 10, and then the pouch 10 was sealed. As the oxygen sensor chip, a non-destructive oxygen sensor chip from Precision Sensing was used.

[0269] The dimensions of each part of the pouch 10 were as follows: Dimension S1 of pouch 10 in first direction D1: 130 mm Dimension S2 of pouch 10 in second direction D2: 165 mm Width W1 of first side seal portion 30: 6 mm Width W2 of second side seal portion 35: 6mm Width of lower seal part 12a W3: 10mm Width of upper seal part 11a W4: 10mm Area of ​​storage area 18 in plan view: 170 cm 2

[0270] The heat sealing conditions were as follows: Heat sealing device: Heat sealer TP-701-A (manufactured by Tester Sangyosha Co., Ltd.) ·Heat welding temperature: 225℃ Heat welding pressure: 0.1MPa Heat welding time: 1 second

[0271] Next, the pouch 10 was subjected to a retort treatment under the following conditions. Method: Spray type Retort temperature: 121℃ Retort time: 30 minutes

[0272] The dissolved oxygen concentration in the storage section 18 of the pouch 10 after the retort treatment was measured using a non-destructive oxygen concentration meter. The non-destructive oxygen concentration meter used was a FIBOX4 OXYGEN METER manufactured by Presence. Four pouches 10 were evaluated, and the average dissolved oxygen concentration was calculated.

[0273] [Evaluation 2: Heat resistance] The pouch 10 in FIG. 4 was produced in the same manner as in Evaluation 1. Then, 150 g of curry was placed in the storage section 18 of the pouch 10, and the pouch 10 was sealed. Ginza Keema Curry by Meiji Co., Ltd. was used as the curry. The dimensions of the pouch and the heat sealing conditions were the same as in Evaluation 1.

[0274] Next, the pouch 10 was heated for 3 minutes in a microwave oven at 600 W. Then, the pouch 10 after heating was visually inspected for the presence or absence of holes. Ten pouches 10 were evaluated.

[0275] [Evaluation 3: Drop strength] The pouch 10 in FIG. 4 was produced in the same manner as in Evaluation 1. Then, 180 mL of pure water was poured into the storage portion 18 of the pouch 10, and the pouch 10 was then sealed. Then, a retort treatment was performed on the pouch 10. The pouch dimensions, heat sealing conditions, and retort conditions were the same as those in Evaluation 1.

[0276] The pouch 10 after the retort treatment was stored in a thermostatic chamber set at 3° C. for one week. Immediately after the pouch 10 was removed from the thermostatic chamber, the pouch 10 was dropped from a height of 120 cm onto a test surface. The test surface was made of concrete. The pouch 10 was dropped in a state in which the side of the pouch 10 on which the sealing process was performed after pouring pure water into the pouch 10 was positioned downward. It was visually confirmed whether or not the pouch 10 had a hole after the drop. Thirty pouches 10 were evaluated.

[0277] The results of Measurement 1 and Evaluations 1 to 3 are shown in the table of FIG. 9. The table of FIG. 9 also shows the layer structure of the packaging material 50. In the column of "Layer Structure", "Film 1", "Printing", "AD1", "Film 2", "AD2", "Film 3", "AD3", and "Sealant" respectively mean the first stretched plastic film 51, the printing layer 61, the first adhesive layer 56, the second stretched plastic film 52, the second adhesive layer 57, the third stretched plastic film 53, the third adhesive layer 58, and the sealant film 55. "IB-PET" means a biaxially stretched PET film provided with a transparent deposition layer 62. "PET" means a biaxially stretched PET film not provided with a transparent deposition layer 62. "CPP1", "CPP2", and "CPP3" mean the first, second, and third types of unstretched polypropylene films. The numbers in parentheses mean the thickness of the layers.

[0278] In the column of "Evaluation 1" in Fig. 9, "great" means that the average dissolved oxygen concentration was 3 ppm or less, "good" means that the average dissolved oxygen concentration was more than 3 ppm and less than 5 ppm, and "not good" means that the average dissolved oxygen concentration was more than 5 ppm. The result of Evaluation 1 for Example 1 was "great".

[0279] In the "Evaluation 2" column in Fig. 9, "great" means that none of the 10 pouches had holes, "good" means that one to two of the 10 pouches 10 had holes, and "not good" means that three or more of the 10 pouches 10 had holes. The result of Evaluation 2 for Example 1 was "great".

[0280] In the "Evaluation 3" column in Fig. 9, "excellent" means that none of the 30 pouches had holes, "great" means that one or two of the 30 pouches 10 had holes, "good" means that three or four of the 30 pouches 10 had holes, and "not good" means that five or more of the 30 pouches 10 had holes. The result of Evaluation 3 for Example 1 was "excellent".

[0281] Example 2 Similarly to the case of Example 1, a packaging material 50 and a pouch 10 were prepared, and Measurement 1 and Evaluations 1 to 3 were performed. The packaging material 50 and the pouch 10 of Example 2 are the same as the packaging material 50 and the pouch 10 of Example 1, except that the transparent deposition layer 62 is provided on the outer surface of the second stretched plastic film 52, not on the inner surface of the first stretched plastic film 51.

[0282] The layer structure of the packaging material 50 of Example 2 is expressed as follows. PET(12) / Printed(1) / AD(3.6) / Vapor deposition / PET(12) / Special AD(3.6) / PET(12) / AD(3.6) / CPP1(60)

[0283] The transition metal content in the second adhesive layer 57 was 35 ppm. The transition metal was cobalt. The result of evaluation 1 was "great". The result of evaluation 2 was "great". The result of evaluation 3 was "great".

[0284] Example 3 In the same manner as in Example 1, a packaging material 50 and a pouch 10 were prepared, and measurement 1 and evaluations 1 to 3 were performed. The packaging material 50 and the pouch 10 of Example 3 were the same as the packaging material 50 and the pouch 10 of Example 1, except that the sealant film 55 was a second type of unstretched polypropylene film instead of the first type of unstretched polypropylene film.

[0285] The layer structure of the packaging material 50 of Example 3 is represented as follows. PET(12) / Metal deposition / Printing(1) / AD(3.6) / PET(12) / Special AD(3.6) / PET(12) / AD(3.6) / CPP2(60)

[0286] The transition metal content in the second adhesive layer 57 was 35 ppm. The transition metal was cobalt. The result of evaluation 1 was "great". The result of evaluation 2 was "good". The result of evaluation 3 was "good".

[0287] Comparative Example 1 In the same manner as in Example 1, a packaging material 50 and a pouch 10 were prepared, and Measurement 1 and Evaluations 1 to 3 were carried out. The packaging material 50 and the pouch 10 of Comparative Example 1 were the same as the packaging material 50 and the pouch 10 of Example 1, except that the second adhesive layer 57 was a normal adhesive layer rather than a special adhesive layer.

[0288] The layer structure of the packaging material 50 of Comparative Example 1 is expressed as follows. PET(12) / Deposition / Mark(1) / AD(3.6) / PET(12) / AD(3.6) / PET(12) / AD(3.6) / CPP1(60)

[0289] The analysis result of the second adhesive layer 57 by ICP-OES is shown in Fig. 11. The transition metal content in the second adhesive layer 57 was 0 ppm.

[0290] The result of evaluation 1 was "not good". The result of evaluation 2 was "great". The result of evaluation 3 was "excellent".

[0291] Comparative Example 2 As in the case of Example 1, a packaging material 50 and a pouch 10 were prepared, and Measurement 1 and Evaluations 1 to 3 were performed. The packaging material 50 and the pouch 10 of Comparative Example 2 are the same as the packaging material 50 and the pouch 10 of Example 1, except that the second adhesive layer 57 is a normal adhesive layer rather than a special adhesive layer, and the third adhesive layer 58 is a special adhesive layer rather than a normal adhesive layer.

[0292] The layer structure of the packaging material 50 of Comparative Example 2 is expressed as follows. PET(12) / Metal deposition / Printing(1) / AD(3.6) / PET(12) / AD(3.6) / PET(12) / Special AD(3.6) / CPP1(60)

[0293] The transition metal content in the third adhesive layer 58 was 35 ppm. The transition metal was cobalt. The result of evaluation 1 was "not good". The result of evaluation 2 was "great". The result of evaluation 3 was "great".

[0294] Comparative Example 3 Similarly to the case of Example 1, a packaging material 50 and a pouch 10 were prepared, and Measurement 1 and Evaluations 1 to 3 were carried out. The packaging material 50 and the pouch 10 of Comparative Example 3 are the same as the packaging material 50 and the pouch 10 of Example 1, except that the second adhesive layer 57 is a normal adhesive layer and not a special adhesive layer, the first adhesive layer 56 is a special adhesive layer and not a normal adhesive layer, and the transparent vapor deposition layer 62 is provided on the outer surface of the second stretched plastic film 52 and not on the inner surface of the first stretched plastic film 51.

[0295] The layer structure of the packaging material 50 of Comparative Example 3 is expressed as follows. PET(12) / Printed(1) / Special AD(3.6) / Vapor deposition / PET(12) / AD(3.6) / PET(12) / AD(3.6) / CPP1(60)

[0296] The transition metal content in the first adhesive layer 56 was 35 ppm. The transition metal was cobalt. The result of evaluation 1 was "not good". The result of evaluation 2 was "great". The result of evaluation 3 was "great".

[0297] Comparative Example 4 In the same manner as in Example 1, a packaging material 50 and a pouch 10 were prepared, and Measurement 1 and Evaluations 1 to 3 were performed. The packaging material 50 and the pouch 10 of Comparative Example 4 were the same as the packaging material 50 and the pouch 10 of Example 1, except that the sealant film 55 was a third type of unstretched polypropylene film instead of the first type of unstretched polypropylene film.

[0298] The layer structure of the packaging material 50 of Comparative Example 4 is expressed as follows. PET(12) / Metal deposition / Printing(1) / AD(3.6) / PET(12) / Special AD(3.6) / PET(12) / AD(3.6) / CPP3(60)

[0299] The transition metal content in the second adhesive layer 57 was 35 ppm. The transition metal was cobalt. The result of evaluation 1 was "great". The result of evaluation 2 was "great". The result of evaluation 3 was "not good".

[0300] In Comparative Example 1, since the packaging material 50 does not include a special adhesive layer, it is considered that the packaging material 50 could not absorb oxygen in the storage section 18. In Comparative Example 2, since the first adhesive layer 56 made of the special adhesive layer is located outside the transparent vapor deposition layer 62, it is considered that the first adhesive layer 56 could not absorb oxygen in the storage section 18. In Comparative Example 3, since the third adhesive layer 58 made of the special adhesive layer is in contact with the sealant film 55, it is considered that the third adhesive layer 58 could not absorb oxygen in the storage section 18. In Examples 1 to 3, since the special adhesive layer is located outside the transparent vapor deposition layer 62 and the special adhesive layer is not in contact with the sealant film 55, it is considered that the special adhesive layer was able to properly absorb oxygen in the storage section 18.

[0301] As can be seen from the comparison between Examples 1 to 3 and Comparative Example 4, from the viewpoint of drop strength, it is considered preferable that the sealant film 55 is made of the first or second type of unstretched polypropylene film. As can be seen from the comparison between Examples 1 and 2 and Example 3, it is considered more preferable that the sealant film 55 is made of the first type, from the viewpoint of heat resistance and drop strength. [Explanation of symbols]

[0302] 10 pouches 11 Top 11a Upper seal part 12 Lower 12a Lower seal part 13 First side 13x 1st side edge 14 Second side 14x 2nd side edge 15 Surface film 16 Back film 17 Lower Film 18 Storage unit 30 First side seal 31 Upper seal part 32 Lower seal part 33 Middle seal part 35 Second side seal 36 Upper seal part 37 Lower seal part 40 First non-sealed part 41 Opening edge 45 Second non-sealed part 46 Opening edge 50 Packaging materials 51 First oriented plastic film 52 Second oriented plastic film 53 Third oriented plastic film 55 Sealant Film 56 First adhesive layer 57 Second adhesive layer 58 3rd adhesive layer 61 Printing layer 62 Transparent vapor deposition layer 63 Gas barrier coating film 64 Barrier Layer

Claims

1. A packaging material comprising, in this order, at least a first stretched plastic film, a first adhesive layer, a second stretched plastic film, a second adhesive layer, a third stretched plastic film, a third adhesive layer, and a sealant film, the packaging material comprises a barrier layer located between the first stretched plastic film and the first adhesive layer, between the first adhesive layer and the second stretched plastic film, or between the second stretched plastic film and the second adhesive layer; At least one of the first adhesive layer, the second adhesive layer, and the third adhesive layer that is located on the inner side of the barrier layer contains an oxygen-absorbing adhesive composition, The sealant film comprises block polypropylene and polyethylene.

2. The packaging material of claim 1 , wherein the third adhesive layer does not include an oxygen absorbing adhesive composition.

3. the packaging material comprises a printing layer located between the first stretched plastic film and the first adhesive layer; The first adhesive layer does not contain an oxygen absorbing adhesive composition, The packaging material of claim 1 , wherein the second adhesive layer comprises an oxygen absorbing adhesive composition.

4. The packaging material according to any one of claims 1 to 3, wherein the barrier layer is located between the first stretched plastic film and the first adhesive layer.

5. The packaging material of claim 4 , wherein the barrier layer comprises a transparent vapor deposition layer.

6. The packaging material according to any one of claims 1 to 3, wherein the barrier layer is located between the first adhesive layer and the second stretched plastic film, or between the second stretched plastic film and the second adhesive layer.

7. The packaging material of claim 6 , wherein the barrier layer comprises a transparent vapor deposition layer.

8. The packaging material according to any one of claims 1 to 3, wherein the content of the block polypropylene in the sealant film is 70% by mass or more and 85% by mass or less.

9. The packaging material according to claim 8, wherein the sealant film is a non-oriented polypropylene film having a tensile elongation of 1000% or more in the machine direction and a tensile elongation of 1100% or more in the perpendicular direction, and having a thickness of 50 μm or more.

10. The packaging material according to any one of claims 1 to 3, wherein the content of the block polypropylene in the sealant film is 80% by mass or more and 96% by mass or less.

11. The packaging material according to claim 10, wherein the sealant film is an unstretched polypropylene film having a tensile elongation of less than 1000% in the machine direction and a tensile elongation of less than 1100% in the perpendicular direction, and having a thickness of 60 μm or more.

12. The oxygen-absorbing adhesive composition contains at least an oxygen-absorbing compound and an oxidation-promoting catalyst, The oxygen absorbing compound contains one or more unsaturated five-membered rings, any bond between the five carbon atoms constituting the unsaturated five-membered ring is a carbon-carbon double bond; a monovalent and / or divalent or higher electron-donating organic group 1 is bonded to the unsaturated five-membered ring; When the number of the unsaturated five-membered rings is one, the unsaturated five-membered ring or the organic group 1 contains a functional group having an active hydrogen, or a group in which the active hydrogen of the functional group having an active hydrogen is substituted with a monovalent organic group 2, The packaging material according to any one of claims 1 to 3, wherein when the number of the unsaturated five-membered rings is two or more, the unsaturated five-membered rings are bonded to each other via a divalent or higher organic group 2 that substitutes an active hydrogen of an active hydrogen group on each of the five-membered rings or the organic group 1.

13. The packaging material according to claim 12, wherein the oxidation-promoting catalyst is a peroxide or a compound containing a cation of a transition metal.

14. The packaging material according to any one of claims 1 to 3, wherein the content of the transition metal constituting the oxidation-promoting catalyst of the oxygen-absorbing adhesive composition in the first adhesive layer or the second adhesive layer is 20 ppm or more.

15. The packaging material according to any one of claims 1 to 3, wherein the first stretched plastic film, the second stretched plastic film and the third stretched plastic film are all stretched polyester films.

16. A pouch in which a storage section for storing contents is defined between a front film and a back film, a steam vent mechanism that discharges steam from the storage section to the outside when the pressure in the storage section increases; A pouch, wherein the front film and the back film are made of the packaging material according to any one of claims 1 to 3.

17. a first side seal portion located on a first side of the pouch and joining an inner surface of the front film and an inner surface of the back film; a second side seal portion located on a second side portion opposite the first side portion of the pouch in a first direction and defining the containing portion between the first side seal portion and the second side seal portion; a first unsealed portion located toward a top of the pouch and separated from the containing portion by the first side seal portion, the first unsealed portion extending to a first edge of the first side of the pouch; the first side seal portion includes an upper seal portion extending along the first side from the first non-seal portion toward an upper portion of the pouch, a lower seal portion extending along the first side from the first non-seal portion toward a lower portion of the pouch, and an intermediate seal portion having one end connected to the upper seal portion and the other end connected to the lower seal portion and positioned between the containing portion and the first non-seal portion, 17. The pouch of claim 16, wherein the first unsealed portion and the intermediate sealed portion comprise the steam venting mechanism.

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