Packaging material and pouch

Abstract

To provide a packaging material and a pouch that are easy to open and have heat resistance.SOLUTION: A packaging material 40 includes, in order from the outer surface side to the inner surface side, at least a first base material layer 41, a first adhesive layer 46, a second base material layer 42, a second adhesive layer 47, and a sealant layer 44. The first base material layer 41 and the second base material layer 42 include a biaxially stretched plastic film. The second base material layer 42 includes a plurality of processed portions having portions penetrating the second base material layer. The first adhesive layer 46 has a softening point of 230.0°C or higher and 245.0°C or lower.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a packaging material and a pouch comprising the packaging material. [Background technology]

[0002] Pouches that can be heated in a microwave oven and are easy to open have been developed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-75289 Summary of the Invention [Problem to be solved by the invention]

[0004] It is not easy to achieve both easy opening and heat resistance at the same time.

[0005] An object of the present invention is to provide a packaging material and a pouch that are easy to open and heat resistant. [Means for solving the problem]

[0006] The embodiments of the present disclosure relate to the following [1] to

[17] . [1] A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first base material layer, a first adhesive layer, a second base material layer, a second adhesive layer, and a sealant layer, The first substrate layer and the second substrate layer include a biaxially oriented plastic film, The second base material layer includes a plurality of processed portions including portions penetrating the second base material layer, The packaging material, wherein the first adhesive layer has a softening point of 230.0°C or higher and 245.0°C or lower.

[0007] [2] In the packaging material described in [1], the second adhesive layer may have a softening point of 230.0°C or higher and 245.0°C or lower.

[0008] [3] In the packaging material according to [1] or [2], the first adhesive layer and the second adhesive layer may contain a cured product of a polyol and an isocyanate compound.

[0009] [4] In the packaging material described in [3], the polyol may include a polyester polyol.

[0010] [5] In the packaging material according to any one of [1] to [4], the processed portions may include a plurality of slits extending in a slit direction.

[0011] [6] In the packaging material described in [5], the slit may have a length of 500 μm or more in the slit direction.

[0012] [7] In the packaging material according to [5] or [6], the slit is A first non-penetrating portion and a second non-penetrating portion are located on an outer surface of the second base material layer, include a recess that does not penetrate the second base material layer, and are aligned in the slit direction; The insulating film may include a through portion that is located between the first non-penetrating portion and the second non-penetrating portion in the slit direction and that passes through the second base material layer.

[0013] [8] In the packaging material described in any one of [5] to [7], the multiple processed portions may include multiple first slits extending in a first slit direction and multiple second slits extending in a second slit direction different from the first slit direction.

[0014] [9] In the packaging material according to any one of [1] to [8], the sealant layer may contain 80% by mass or more of block polypropylene, an elastomer, and polyethylene.

[0015]

[10] In the packaging material described in [9], the elastomer may contain an ethylene-α-olefin copolymer.

[0016]

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

[10] , the first base material layer may contain polyester, and the second base material layer may contain polyamide.

[0017]

[12] A pouch in which a storage section for storing contents is defined between a front film and a back film, a seal portion that joins the sealant layer of the front surface film and the sealant layer of the back surface film; and an opening means including a plurality of the processed portions of the front surface film and a plurality of the processed portions of the back surface film, The front surface film and the back surface film include the packaging material according to any one of claims 1 to 4, The seal portion includes a first side seal portion located on a first side edge of the pouch, and a second side seal portion located on a second side edge of the pouch opposite to the first side edge, and defining the containing portion between the first side seal portion and the second side seal portion, The opening means extends across the container from the first side seal to the second side seal.

[0018]

[13] The pouch described in

[12] may further include a bottom film located between the surface film and the back film, and the seal portion may further include a first bottom seal portion located at the lower edge of the pouch and joining the inner surface of the surface film to the inner surface of the bottom film and the inner surface of the back film to the inner surface of the bottom film.

[0019]

[14] The pouch according to

[12] or

[13] may be provided with a steam venting mechanism.

[0020]

[15] In the pouch described in

[14] , the opening means may be located below the steam release mechanism.

[0021]

[16] In the pouch described in any one of

[12] to

[15] , the steam release mechanism may include an isolating sealed portion and an unsealed portion isolated from the containing portion by the isolating sealed portion.

[0022]

[17] In the pouch described in

[16] , the unsealed portion may extend to reach the first side edge. Effect of the Invention

[0023] According to the present invention, a packaging material and a pouch having easy-open properties and heat resistance can be provided. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a front view showing a pouch according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded view showing the packaging material that makes up the pouch according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view showing an example of a layer structure of a packaging material. [Figure 4] FIG. 2 is a cross-sectional view showing an example of a layer structure of a packaging material. [Diagram 5] FIG. 4 is a plan view showing details of the opening means. [Figure 6] 1 is a cross-sectional view of the packaging material cut along the slit direction. [Figure 7] FIG. 2 is a front view of a sealed pouch. [Figure 8] FIG. 4 is a cross-sectional view showing the state of a pouch when heated in an embodiment. [Figure 9] FIG. 4 is a cross-sectional view showing the state of a pouch when heated in an embodiment. [Figure 10] FIG. 11 is a cross-sectional view showing the state of a pouch when heated in a comparative embodiment. [Figure 11] FIG. 13 is a front view showing a modified example of the pouch. [Figure 12] FIG. 2 is a diagram for explaining a method for measuring a softening point. [Figure 13] FIG. 2 is a diagram for explaining a method for measuring a softening point. [Figure 14] FIG. 2 is a diagram for explaining a method for measuring a softening point. [Figure 15] FIG. 2 is a diagram for explaining a method for measuring a softening point. [Figure 16] 1 is a table showing the evaluation results in Examples 1 to 3 and Comparative Examples 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the present disclosure is not limited to the embodiments and examples described below. Note that the drawings shown below are schematic. Therefore, the size and shape of each part are appropriately exaggerated to make it easier to understand.

[0026] The numerical values ​​such as dimensions of each member and the names of materials described in this specification are examples of embodiments, and are not limited to these, and may be appropriately selected and used. In this specification, terms specifying shapes and geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include substantially the same state in addition to their strict meanings.

[0027] 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.

[0028] <Pouch composition> FIG. 1 is a front view showing a pouch 10 according to an embodiment of the present disclosure. The pouch 10 includes an upper edge 14, a lower edge 13 opposite the upper edge 14, a first side edge 11 extending between the upper edge 14 and the lower edge 13, and a second side edge 12. The lower edge 13 and the upper edge 14 face each other in a first direction D1. The first side edge 11 and the second side edge 12 face each other in a second direction D2. The first direction D1 and the second direction D2 may be perpendicular to each other. In this specification, the upper edge 14 side may be referred to as the upper side and the lower edge 13 as the lower side along the first direction D1.

[0029] In this embodiment, the pouch 10 is a standing pouch having a rectangular shape in a front view and a bottom gusset. The names "upper edge", "lower edge", and "side edge", as well as the terms "upper side" and "lower side", merely indicate the relative positions and directions of the pouch 10 and its components based on a state in which the pouch 10 stands on its own with the bottom gusset at the bottom. The position of the pouch 10 during transportation or use is not limited by the names and terms in this specification. In this disclosure, a rectangle is a concept that includes not only a rectangle with four right-angled corners, but also a rectangle with four chamfered corners that are convex outwardly in a circular arc shape.

[0030] 1, the upper edge 14 of the pouch 10 is not sealed, and the pouch 10 is not filled with any contents. The pouch 10 in the present disclosure is not limited to the pouch 10 in an unfilled state, but also includes the pouch 10 in an filled state.

[0031] <Pouch structure> FIG. 2 is an exploded view showing the films constituting the pouch 10 according to an embodiment of the present disclosure. As shown in FIG. 2, the pouch 10 of the embodiment is composed of three films: a substantially rectangular front (front) film 1, a back film 2 having the same shape as the front film 1, and a substantially rectangular bottom film 3. The pouch 10 of the present embodiment is formed by heat-sealing the inner surfaces of the three films, the front film 1, the back film 2, and the bottom film 3, at predetermined locations. As shown in FIG. 2, the bottom film 3 is folded in half and divided into a first portion 3f and a second portion 3g with the folded portion 3a as the boundary. The bottom film 3 is provided with four semicircular arc-shaped second cutout portions 3b, 3c, 3d, and 3e that cut out the side edges, and the second cutout portions 3b and 3c and the second cutout portions 3d and 3e are provided at positions that correspond to when the film is folded in half. A second bottom seal portion 7b, which will be described later, is formed via the second cutout portions 3b to 3e.

[0032] From the viewpoint of stabilizing the self-supporting property when cooking using a microwave oven, it is preferable that the distance L3 from the folded-in portion 3a to the lower edge 13 of the pouch 10 in the direction perpendicular to the folded-in portion 3a is equal to or greater than a predetermined value. The distance L3 is, for example, equal to or greater than 35 mm, and may be equal to or greater than 40 mm. The distance L3 is, for example, equal to or less than 60 mm, and may be equal to or less than 50 mm.

[0033] <Components of the pouch> The pouch 10 comprises a storage section 71, a sealed section, an opening means 18, and a steam release mechanism 20. The storage section 71 is a space in which the contents are stored. An unsealed section surrounded by the sealed section constitutes the storage section 71. The unsealed section includes a front film 1 and a back film 2 whose inner surfaces are not joined to each other.

[0034] <Sealing section> The seal portion is a portion that joins the inner surfaces of two films together. As described below, the inner surface of each film is formed of a sealant layer. Therefore, the seal portion joins the sealant layers of the two films together.

[0035] 1, the seals include a first side seal 5, a second side seal 6, a bottom seal 7, and an isolation seal 20b. An opening 15 is formed in the upper edge 14.

[0036] The first side seal portion 5, the second side seal portion 6, and the isolating seal portion 20b are formed by joining the inner surface of the front film 1 and the inner surface of the back film 2 by thermal welding. The first side seal portion 5 is located at the first side edge 11. The second side seal portion 6 is located at the second side edge 12. An unsealed portion constituting the storage portion 71 is defined between the first side seal portion 5 and the second side seal portion 6. In the example shown in FIG. 1, the unsealed portion surrounded by the first side seal portion 5, the second side seal portion 6, the bottom seal portion 7, and the isolating seal portion 20b constitutes the storage portion 71.

[0037] The isolating seal portion 20b isolates the unsealed portion 20a from the storage portion 71. The unsealed portion 20a and the isolating seal portion 20b constitute the steam release mechanism 20.

[0038] The pouch 10 may include an unsealed portion 30a adjacent the second side edge 12. The unsealed portion 30a is separated from the containing portion 71 by the second side seal 6. The unsealed portion 30a may face the unsealed portion 20a in the second direction D2. The unsealed portion 30a may be in the same position as the unsealed portion 20a in the first direction D1.

[0039] A single pouch 10 may be obtained by forming sealed portions and unsealed portions of a plurality of pouches 10 along the length direction of the long front surface film 1 and back surface film 2, and cutting the films 1 and 2. In this case, the unsealed portion 20a and the unsealed portion 30a may be formed by cutting one unsealed portion. This allows the unsealed portion 20a to be reliably formed and reduces the amount of waste when manufacturing the pouch 10.

[0040] The first side seal 5 may include a lower portion 5a and an upper portion 5b. The lower portion 5a extends along the first side edge 11 from the unsealed portion 20a toward the bottom edge 13. The upper portion 5b extends along the first side edge 11 from the unsealed portion 20a toward the top edge 14.

[0041] The second side seal 6 may include a lower portion 6a and an upper portion 6b. The lower portion 6a extends along the second side edge 12 from the unsealed portion 30a toward the bottom edge 13. The upper portion 6b extends along the second side edge 12 from the unsealed portion 30a toward the top edge 14.

[0042] The widths W1, W4 of the lower portions 5a, 6a are, for example, 5 mm or more, and may be 6 mm or more. The widths W1, W4 of the lower portions 5a, 6a are, for example, 8 mm or less, and may be 7 mm or less. The widths W2, W5 of the upper portions 5b, 6b are, for example, 8 mm or more, and may be 10 mm or more. The widths W2, W5 of the upper portions 5b, 6b are, for example, 15 mm or less, and may be 13 mm or less. The widths W2, W5 of the upper portions 5b, 6b may be greater than the widths W1, W4 of the lower portions 5a, 6a. The width of the seal portion is the dimension of the seal portion in a direction perpendicular to the direction in which the seal portion extends.

[0043] The bottom seal portion 7 is a seal portion formed on the lower edge 13 side of the folded-in portion 3a. The bottom seal portion 7 may include a first bottom seal portion 7a and a second bottom seal portion 7b. The first bottom seal portion 7a includes a portion joining the inner surface of the surface film 1 to the inner surface of the first portion 3f of the bottom film 3, and a portion joining the inner surface of the back film 2 to the inner surface of the second portion 3g of the bottom film 3. The second bottom seal portion 7b joins the inner surface of the surface film 1 to the inner surface of the back film 2 via the second cutout portions 3b, 3c, 3d, and 3e.

[0044] <Bottom gusset> A first portion 3f of the bottom film 3 and a portion of the surface film 1 overlapping the first portion 3f form a first pleat. A second portion 3g of the bottom film 3 and a portion of the surface film 1 overlapping the second portion 3g form a second pleat. The first pleat and the second pleat form a bottom gusset 9. The front view of FIG. 1 shows the first pleat, which is located closer to the lower edge 13 than the fold-in portion 3a. The pouch 10 is able to stand on its own by having the bottom gusset 9.

[0045] <Containment Unit> After the contents are accommodated through opening 15, top seal portion 4 is formed along top edge 14, and pouch 10 is sealed, as shown in Fig. 7 described below. Top seal portion 4 is formed continuously from first side seal portion 5 to second side seal portion 6. Container portion 71 is defined by the inner edge of first side seal portion 5, the inner edge of second side seal portion 6, the inner edge of first bottom seal portion 7a, the inner edge of top seal portion 4, and the inner edge of isolation seal portion 20b.

[0046] <Contents> The contents include moisture and oil. Examples of the contents are retort foods, frozen foods, refrigerated foods, etc. Examples of foods are curry, porridge, yakisoba, side dishes, fish, etc. When the pouch 10 is heated by a microwave oven or the like, the moisture in the contents evaporates as the pouch 10 is heated, increasing the pressure in the storage section 71 of the pouch 10. For this reason, a steam vent function is required to release steam from within the storage section 71 to the outside.

[0047] <Film details> 3 is a cross-sectional view showing an example of the layer structure of the packaging material 40 constituting the pouch 10 according to this embodiment. The front film 1 and the back film 2 are composed of the packaging material 40. The bottom film 3 may also be composed of the packaging material 40.

[0048] The packaging material 40 is a laminate consisting of a plurality of layers stacked together. The packaging material 40 includes at least a first base material layer 41, a first adhesive layer 46, a second base material layer 42, a second adhesive layer 47, and a sealant layer 44, in this order from the outer surface 401 side to the inner surface 402 side. The packaging material 40 may include a printed layer 45 located between the first base material layer 41 and the first adhesive layer 46. The first base material layer 41 may form the outer surface 401 of the packaging material 40. The sealant layer 44 may form the inner surface 402 of the packaging material 40.

[0049] Fig. 4 is a cross-sectional view showing an example of a layer configuration of the packaging material 40. The packaging material 40 may include a vapor deposition layer 48 located on the surface of the first base material layer 41 or the surface of the second base material layer 42. In the example shown in Fig. 4, the vapor deposition layer 48 is located on the inner surface of the first base material layer 41. The packaging material 40 may include a coating layer 49 located on the surface of the vapor deposition layer 48.

[0050] Each layer of the packaging material 40 will now be described.

[0051] When the pouch 10 is heated in a microwave oven, heat resistance is required for the pouch 10. The first base material layer 41 and the second base material layer 42 preferably have heat resistance.

[0052] For example, the material of the first base layer 41 and the second base layer 42 may be a polyester film such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), a polyamide film such as nylon, or a polypropylene film. The thickness of the first base layer 41 and the second base layer 42 is, for example, 10 μm or more, and may be 12 μm or more. The thickness of the first base layer 41 and the second base layer 42 is, for example, 50 μm or less, and may be 40 μm or less, 25 μm or less, or 18 μm or less.

[0053] The first base layer 41 and the second base layer 42 may be biaxially stretched plastic films that are biaxially stretched plastic films. The material of the first base layer 41 may be the same as or different from the material of the second base layer 42. The thickness of the first base layer 41 may be the same as or different from the thickness of the second base layer 42.

[0054] In this embodiment, it is particularly preferable to use polyethylene terephthalate (PET) as the first base material layer 41. It is also particularly preferable to use polyamide, polybutylene terephthalate (PBT), or the like as the second base material layer 42. It is more preferable that the second base material layer 42 is a biaxially stretched film containing polyamide such as nylon as the main component. In one layer, the "main component" means a component having a content of 51% by mass or more in that layer.

[0055] The first base material layer 41 and the second base material layer 42 may contain a material derived from biomass. For example, the first base material layer 41 and the second base material layer 42 may contain a biomass-derived polyester.

[0056] Although not shown, the packaging material 40 may include three or more substrate layers. For example, the packaging material 40 may include a third substrate layer located between the second substrate layer 42 and the sealant layer 44. The third substrate layer may include a biaxially oriented plastic film, similar to the first substrate layer 41 and the second substrate layer 42.

[0057] An example of the layer structure when the packaging material 40 includes three base material layers is shown below. Vapor-deposited polyethylene terephthalate (PET) 12 μm / First adhesive layer / Stretched polyamide (ONY) 15 μm / Second adhesive layer / Stretched polyethylene terephthalate (PET) 12 μm / Third adhesive layer / Non-oriented polypropylene (CPP) 60 μm The " / " denotes the boundary between two layers.

[0058] The first adhesive layer 46 contains an adhesive for bonding the first base material layer 41 and the second base material layer 42 by a dry lamination method. The second adhesive layer 47 contains an adhesive for bonding the second base material layer 42 and the sealant layer 44 or the third base material layer by a dry lamination method.

[0059] The adhesive includes a cured product produced by the reaction of the main agent and the curing agent. The cured product may be produced from an adhesive composition prepared by mixing a first composition including the main agent and a solvent with a second composition including the curing agent and a solvent. The cured product may be produced by reacting the main agent and the curing agent without using a solvent. In the following description, an adhesive including a cured product produced by reacting the main agent and the curing agent using a solvent is also referred to as a solvent-based adhesive. In the following description, an adhesive including a cured product obtained without using a solvent is also referred to as a solventless adhesive.

[0060] The first adhesive layer 46 may contain a solvent-based adhesive or a solventless adhesive, and the second adhesive layer 47 may contain a solvent-based adhesive or a solventless adhesive.

[0061] An example of the adhesive is polyurethane. Polyurethane is a cured product produced by reacting a polyol as a base agent with an isocyanate compound as a curing agent. Examples of polyurethane are polyether polyurethane, polyester polyurethane, etc. Polyether polyurethane is a cured product produced by reacting a polyether polyol as a base agent with an isocyanate compound as a curing agent. Polyester polyurethane is a cured product produced by reacting a polyester polyol as a base agent with an isocyanate compound as a curing agent.

[0062] Examples of the isocyanate compound include aromatic isocyanate compounds, aliphatic isocyanate compounds, and adducts or oligomers of isocyanate compounds. Examples of aromatic isocyanate compounds include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), etc. Examples of aliphatic isocyanate compounds include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc.

[0063] The thickness of the first adhesive layer 46 and the second adhesive layer 47 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 first adhesive layer 46 and the second adhesive layer 47 is, for example, 5.0 μm or less, may be 4.0 μm or less, or may be 3.0 μm or less.

[0064] The material of the first adhesive layer 46 may be the same as or different from the material of the second adhesive layer 47. The thickness of the first adhesive layer 46 may be the same as or different from the thickness of the second adhesive layer 47.

[0065] The printed layer 45 is provided to display the product contents, to impart an aesthetic feel, to display the cut portion, etc. The printed layer 45 is formed from printing ink containing a binder and a pigment.

[0066] The deposition layer 48 is provided on the surface of the base material layer to enhance the gas barrier property of the packaging material 40. The deposition layer 48 may be transparent. The deposition layer 48 may be composed of a single deposition layer or may include two or more deposition layers. When the deposition layer 48 includes two or more deposition layers, each layer may have the same composition or different compositions. The deposition layer 48 may be formed by a physical vapor deposition method or a chemical vapor deposition method. Examples of the physical vapor deposition method include a vacuum deposition method, a sputtering method, and an ion plating method. Examples of the chemical vapor deposition method include a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, and a photochemical vapor deposition method. The deposition layer may be formed on the surface of the base material layer on a film formation roller using a roller-type deposition film formation device.

[0067] The deposition layer 48 may be made of a transparent inorganic material. Examples of inorganic materials include metal oxides and inorganic oxides. Examples of metal oxides include oxides of metals such as aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y). Examples of inorganic oxides include oxides of silicon (Si). Aluminum oxide (aluminum oxide) and silicon oxide are preferred because they are transparent.

[0068] The thickness of the deposition layer 48 is, for example, 20 Å or more, optionally 30 Å or more, optionally 40 Å or more, optionally 50 Å or more, optionally 60 Å or more, or optionally 70 Å or more. The thickness of the deposition layer 48 is, for example, 150 Å or less, optionally 130 Å or less, optionally 120 Å or less, or optionally 110 Å or less.

[0069] The coating layer 49 is provided on the surface of the deposition layer 48 in order to further improve the gas barrier property of the packaging material 40. The coating layer 49 may be transparent. The coating layer 49 is formed by applying a gas barrier composition containing at least one alkoxide and a polyvinyl alcohol resin and / or an ethylene-vinyl alcohol copolymer onto the deposition layer 48. The gas barrier composition may be obtained by polycondensation by a sol-gel method in the presence of a sol-gel catalyst, an acid, water, a solvent, etc. The alkoxide is a compound represented by the general formula R 1 n M(OR 2 ) m (In the formula, R 1 , R 2 represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M.

[0070] The above general formula R 1 n M(OR 2 ) m As the alkoxide represented by the formula (I), at least one of the following may be used: partial hydrolysis product of alkoxide, and condensation product of hydrolysis of alkoxide. In addition, the partial hydrolysis product of alkoxide does not need to have all alkoxy groups hydrolyzed, and may be one in which one or more alkoxy groups are hydrolyzed, or a mixture thereof. As the condensation product of hydrolysis of alkoxide, a dimer or more of the partially hydrolyzed alkoxide, specifically, a dimer to hexamer, is used.

[0071] The above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula (I), examples of the metal atom represented by M include silicon, zirconium, titanium, aluminum, etc. 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.

[0072] The above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula: 1 Examples of the organic group represented by the general formula R above include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, and n-octyl. 1 n M(OR 2 ) m In the alkoxide represented by the formula: 2 Examples of the organic group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, etc. When two or more alkyl groups are contained in the same molecule, the two or more alkyl groups may be the same or different.

[0073] When preparing the transparent gas barrier composition, for example, a silane coupling agent may be added. An example of the silane coupling agent is an organoalkoxysilane containing an organic reactive group. In particular, an organoalkoxysilane having an epoxy group is preferably used. Specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane is used. The silane coupling agent may be used alone or in combination of two or more kinds.

[0074] The thickness of the coating layer 49 is, for example, 100 nm or more, and may be 125 nm or more, 150 nm or more, or 200 nm or more. This allows stable gas barrier properties to be obtained. The thickness of the coating layer 49 is, for example, 500 nm or less, and may be 450 nm or less, 400 nm or less, or 300 nm or less.

[0075] Next, the sealant layer 44 will be described. The sealant layer 44 may be composed of one layer, or may include two or more layers. The sealant layer 44 is preferably made of an unstretched 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 tension applied during film formation.

[0076] The sealant layer 44 may satisfy at least one of the following (1) or (2). (1) The Young's modulus of the film constituting the sealant layer 44 is less than 1000 MPa in one direction and in a direction perpendicular to the one direction. (2) The tensile elongation of the film constituting the sealant layer 44 is 300% or more in one direction and in a direction perpendicular to the one direction. The one direction and the direction perpendicular to the one direction are, for example, a first direction D1 and a second direction D2.

[0077] The Young's modulus and tensile elongation of the sealant layer 44 are measured in accordance with JIS K7127. Using a Tensilon universal material testing machine RTC-1310A (manufactured by A&D Co., Ltd.), the test piece is held for 1 minute in an environment with a temperature of 23°C and a relative humidity of 50%, and then the Young's modulus and tensile elongation of the test piece are measured in an environment with a temperature of 23°C and a relative humidity of 50%. The measurement is performed using a rectangular test piece with one side of 15 mm and the other side extending in a direction perpendicular to the one side of 150 mm. The measurement is performed in an environment of 23°C after the test piece is held for 1 minute in an environment of 23°C. The initial distance between a pair of gripping tools holding the test piece is 100 mm, and the tensile speed is 300 mm / min. As long as the initial distance between the pair of gripping tools can be measured as 100 mm, the length in the direction perpendicular to one side can be adjusted.

[0078] The pouch 10 made of the packaging material 40 is subjected to a sterilization treatment at high temperatures, such as boiling or retort treatment. The sealant layer 44 preferably has heat resistance sufficient to withstand such high temperature treatments.

[0079] The melting point of the material constituting the sealant layer 44 is preferably 150° C. or higher, and more preferably 160° C. or higher. By increasing the melting point of the sealant layer 44, 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 sealant layer 44 is lower than the melting point of the resin constituting the base layer.

[0080] The sealant layer 44 may include a material containing propylene as a main component. For example, the sealant layer 44 may include polypropylene as a main component. The polypropylene content in the sealant layer 44 is, for example, 51% by mass or more, 80% by mass or more, 86% by mass or more, or 90% by mass or more. The polypropylene content in the sealant layer 44 is, for example, 98% by mass or less, 96% by mass or less, or 94% by mass or less.

[0081] The sealant layer 44 may contain a matrix resin component and a dispersed component. For example, the sealant layer 44 may have a so-called sea-island structure in which the matrix resin component is a sea component, the dispersed component is an island component, and the island component is dispersed in the sea component.

[0082] The matrix resin component may be made of 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.

[0083] The block polypropylene may include 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 include a sea part made of a propylene polymer and an island part made of polyethylene and an ethylene-propylene copolymer rubber component. The polymer part (a) and the sea part can contribute to improving the heat resistance, rigidity, blocking resistance and seal strength of the block polypropylene. The polymer part (b) and the island part 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 part to the island part, the mechanical properties of the sealant layer 44 containing the block polypropylene can be adjusted.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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%.

[0088] 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%.

[0089] The content of the matrix resin component in the sealant layer 44 is higher than the content of the dispersed component in the sealant layer 44. The content of the matrix resin component in the sealant layer 44 is, for example, 70 mass % or more, may be 75 mass % or more, may be 80 mass % or more, or may be 85 mass % or more. The content of the matrix resin component in the sealant layer 44 is, for example, 96 mass % or less, and may be 90 mass % or less.

[0090] The dispersion component may include polyethylene, which may contribute to increasing the impact resistance of the sealant layer 44. Examples of polyethylene include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and the like.

[0091] The polyethylene content of the dispersed component in the sealant layer 44 is, for example, 2 mass% or more, optionally 4 mass% or more, optionally 10 mass% or more, or optionally 15 mass% or more. The polyethylene content of the dispersed component in the sealant layer 44 is, for example, 30 mass% or less, optionally 20 mass% or less, optionally 15 mass% or less, or optionally 10 mass% or less.

[0092] The dispersion component may include an elastomer. The elastomer may contribute to increasing the impact resistance of the sealant layer 44. Examples of the elastomer include a propylene-ethylene copolymer (propylene-ethylene elastomer), an ethylene-α-olefin copolymer (ethylene-α-olefin elastomer), and the like.

[0093] The content of the elastomer in the dispersed component in the sealant layer 44 is, for example, 2 mass % or more, and may be 4 mass % or more. The content of the elastomer in the dispersed component in the sealant layer 44 is, for example, 10 mass % or less, and may be 8 mass % or less.

[0094] The dispersion component may include both the above-mentioned polyethylene and the above-mentioned elastomer. The dispersion component may include the above-mentioned polyethylene but not the above-mentioned elastomer.

[0095] The thickness of the sealant layer 44 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 layer 44 is, for example, 100 μm or less, and may be 80 μm or less.

[0096] There are mainly two types of sealant layer 44 containing a matrix resin component made of block polypropylene. The first type has high tensile elongation and impact resistance. The first type of sealant layer 44 preferably further has a property of low hot seal strength. This can prevent the pressure in the containing section 71 from becoming excessive when the pouch 10 is heated. This can prevent damage to the packaging material 40.

[0097] The second type has a high Young's modulus. By using the second type of sealant layer, the tearability when opening the pouch 10 can be improved.

[0098] In the first type sealant layer 44, the content of the matrix resin component in the sealant layer 44 is, for example, 70 mass % or more, and may be 75 mass % or more. The content of the matrix resin component in the sealant layer 44 is, for example, 85 mass % or less, and may be 80 mass % or less.

[0099] In the first type of sealant layer 44, the dispersion component may include the polyethylene described above. In the first type of sealant layer 44, the dispersion component may not include the elastomer described above.

[0100] In the first type of sealant layer 44, the polyethylene of the dispersion component is 0.90 g / cm 3 Above 0.93g / cm 3 The polyethylene of the dispersed component in the first type sealant layer 44 may have a density of 0.1 to 1.0 MPa (0.2 to 1.0 MPa). In the first type sealant layer 44, the polyethylene of the dispersed component may be a linear low density polyethylene. The content of the polyethylene of the dispersed component in the sealant layer 44 may be, for example, 15% by mass or more, and may be 20% by mass or more. The content of the polyethylene of the dispersed component in the sealant layer 44 may be, for example, 30% by mass or less, and may be 25% by mass or less.

[0101] The tensile elongation of the first type sealant layer 44 in the machine direction (MD) at 23°C may be, for example, 800% or more, 900% or more, 1000% or more, or 1100% or more. The product of the tensile elongation (%) and the thickness (μm) of the first type sealant layer 44 in the machine direction (MD) may be, for example, 45,000 or more, 50,000 or more, 55,000 or more, or 60,000 or more. The tensile elongation of the first type sealant layer 44 in the transverse direction (TD) at 23°C may be, for example, 1,050% or more, or 1100% or more. The product of the tensile elongation (%) and the thickness (μm) of the first type sealant layer 44 in the transverse direction (TD) may be, for example, 53,000 or more, or 60,000 or more. The sealant layer 44 has a high tensile elongation, so that the pouch 10 can be prevented from breaking due to an impact when dropped, for example.

[0102] The Young's modulus of the first type sealant layer 44 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 layer 44 in the machine direction (MD) is, for example, 38,000 or less, and may be 35,000 or less. The Young's modulus of the first type sealant layer 44 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 layer 44 in the transverse direction (TD) is, for example, 30,000 or less, and may be 25,000 or less.

[0103] In the second type sealant layer 44, the content of the matrix resin component in the sealant layer 44 is, for example, 80 mass % or more, and may be 85 mass % or more. The content of the matrix resin component in the sealant layer 44 is, for example, 96 mass % or less, and may be 90 mass % or less.

[0104] In the second type of sealant layer 44, the dispersion component may include both the polyethylene described above and the elastomer described above.

[0105] In the second type of sealant layer 44, the polyethylene of the dispersion component is 0.94 g / cm 3 Above 0.97g / cm 3 The polyethylene content of the dispersed component in the sealant layer 44 is, for example, 2 mass % or more, and may be 4 mass % or more. The polyethylene content of the dispersed component in the sealant layer 44 is, for example, 10 mass % or less, and may be 8 mass % or less.

[0106] In the second type sealant layer 44, the elastomer of the dispersed component 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 layer 44 may have a density of 0.1 to 1.0 mm or less. The elastomer content of the dispersed components in the sealant layer 44 is, for example, 2% by mass or more, and may be 4% by mass or more. The polyethylene content of the dispersed components in the sealant layer 44 is, for example, 10% by mass or less, and may be 8% by mass or less.

[0107] The Young's modulus of the second type sealant layer 44 in the machine direction (MD) at 23°C is, for example, 500 MPa or more, 600 MPa or more, 650 MPa or more, or 700 MPa or more. The product of the Young's modulus (MPa) and the thickness (μm) of the second type sealant layer 44 in the machine direction (MD) is, for example, 35,000 or more, 38,000 or more, or 45,000 or more. The Young's modulus of the second type sealant layer 44 in the transverse direction (TD) at 23°C is, for example, 450 MPa or more, 500 MPa or more, 550 MPa or more, or 600 MPa or more. The product of the Young's modulus (MPa) and the thickness (μm) of the second type sealant layer 44 in the transverse direction (TD) is, for example, 25,000 or more, 30,000 or more, 35,000 or more, or 38,000 or more.

[0108] The tensile elongation of the second type sealant layer 44 in the machine direction (MD) at 23°C is, for example, 1100% or less, may be 1000% or less, 900% or less, or may be 800% or less. The product of the tensile elongation (%) and the thickness (μm) of the second type sealant layer 44 in the machine direction (MD) is, for example, 55000 or less, or may be 50000 or less. The tensile elongation of the second type sealant layer 44 in the transverse direction (TD) at 23°C is, for example, 1200% or less, may be 1100% or less, 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 layer 44 in the transverse direction (TD) is, for example, 60000 or less, or may be 55000 or less.

[0109] <Steam release mechanism> The steam release mechanism 20 can function to release steam in the storage section 71 to the outside of the pouch 10 when the pressure in the storage section 71 exceeds a predetermined value. The steam release mechanism 20 may be provided on the first side edge 11. The steam release mechanism 20 includes an unsealed portion 20a for allowing steam to escape, and an isolating sealed portion 20b for isolating the unsealed portion 20a and the storage section 71.

[0110] The steam release mechanism 20 is located closer to the upper edge 14 of the pouch 10. That is, the steam release mechanism 20 is formed at a position closer to the upper edge 14 of the pouch 10 than to the lower edge 13 of the pouch 10. For example, the steam release mechanism 20 is provided between the upper edge 14 of the pouch 10 and a midpoint 25. The midpoint 25 is the midpoint between the upper edge 14 of the pouch 10 and the lower edge 13 of the pouch 10 in the first direction D1.

[0111] The unsealed portion 20a is a portion where the front film 1 and the back film 2 are not sealed. The unsealed portion 20a may extend to reach the first side edge 11 of the pouch 10. In this case, an opening 21 is formed between the front film 1 and the back film 2 at the first side edge 11 of the pouch 10. The unsealed portion 20a is isolated from the storage portion 71 by the isolating seal portion 20b. In this embodiment, the unsealed portion 20a is rectangular and includes a first edge 22, a second edge 23, and a third edge 24 in addition to the first side edge 11 where the opening 21 is present. The unsealed portion 20a is provided to communicate with the storage portion 71 and release steam in the pouch 10 to the outside when the pressure in the pouch 10 increases due to steam generated by heating in a microwave oven. The unsealed portion 20a protrudes from the first side edge 11 of the pouch 10 toward the storage portion 71. In this embodiment, the unsealed portion 20a is made of a front film 1 and a back film 2 that are overlapped without being thermally welded. Therefore, an opening 21 is formed in the unsealed portion 20a and is defined by the edge of the overlapping packaging materials.

[0112] The isolation seal portion 20b is a portion that is heat-sealed to isolate the unsealed portion 20a from the storage portion 71. The isolation seal portion 20b may include a first end connected to the lower portion 5a and a second end connected to the upper portion 5b. The width W3 of the isolation seal portion 20b may be smaller than the width W1 of the lower portion 5a. The width W3 of the isolation seal portion 20b may be, for example, 2.5 mm or more, or 3.0 mm or more. The width W3 of the isolation seal portion 20b may be, for example, 5.0 mm or less, or 4.0 mm or less. The inner edge of the isolation seal portion 20b protrudes toward the storage portion 71, and the outer edge of the isolation seal portion 20b overlaps the entire third edge 24, a part of the first edge 22, and a part of the second edge 23.

[0113] In FIG. 1, the symbol L1 indicates the distance in the second direction D2 between the inner edge of the isolating seal portion 20b and the inner edge 5a1 of the lower portion 5a. The symbol L2 indicates the distance in the second direction D2 between the inner edge of the isolating seal portion 20b and the inner edge 5b1 of the upper portion 5b. The distance L1 may be greater than the distance L2. The distance L1 may be, for example, 3 mm or more, or 6 mm or more. The distance L1 may be, for example, 15 mm or less, or 12 mm or less. By setting the distance L1 to 3 mm or more, it is possible to suppress the progression of peeling of the seal portion other than the isolating seal portion 20b. By setting the distance L1 to 15 mm or less, it is possible to suppress the flow of the contents from being hindered by the isolating seal portion 20b when the contents are filled into the pouch 10 from the opening 15 of the upper edge 14.

[0114] The distance L1 may be greater than the width W3 of the isolating seal portion 20b. In this case, the third edge 24 of the unsealed portion 20a is located inside the inner edge 5a1 of the lower portion 5a of the first side seal portion 5. That is, the unsealed portion 20a protrudes inward from the inner edge 5a1 of the lower portion 5a. The unsealed portion 30a located at the second side edge 12 does not have to protrude inward from the inner edge 6a1 of the lower portion 6a of the second side seal portion 6.

[0115] <Method of opening> The opening means 18 is a structure for enhancing the tearability of the pouch 10 and the packaging material 40. The opening means 18 extends in the second direction D2 from the first side seal portion 5 to the second side seal portion 6 so as to cross the containing portion 71. A user can easily open the pouch 10 after it has been heated by tearing the pouch 10 along the opening means 18. The opening means 18 is formed in a band-shaped region extending in the second direction D2. In FIG. 1, the region where the opening means 18 is formed is hatched.

[0116] The opening means 18 may be located below the steam venting mechanism 20. The opening means 18 may be located above the midpoint 25.

[0117] 5 is a plan view showing the details of the opening means 18. The opening means 18 includes a plurality of processed portions 55 arranged along the second direction D2. The processed portions 55 are structures formed in the packaging material 40 by partially processing at least one layer of the packaging material 40. For example, the processed portions 55 include holes formed in at least one layer of the packaging material 40. The holes may or may not penetrate one layer of the packaging material 40. A hole that does not penetrate a layer is also called a depression.

[0118] Both the packaging material 40 constituting the front film 1 and the packaging material 40 constituting the back film 2 may include a plurality of processed portions 55. Only one of the packaging material 40 constituting the front film 1 and the packaging material 40 constituting the back film 2 may include a plurality of processed portions 55.

[0119] The processing portion 55 may be a slit 50 that extends linearly in the slit direction. The slit 50 is formed, for example, by inserting a blade into at least one layer of the packaging material 40.

[0120] The multiple processed portions 55 may include multiple first slits 50A extending in the first slit direction D3 and multiple second slits 50B extending in the second slit direction D4. The multiple first slits 50A may be aligned in the second direction D2. The multiple second slits 50B may be aligned in the second direction D2. A combination of one first slit 50A and one second slit 50B is also referred to as a slit pair.

[0121] The multiple first slits 50A may be located above the imaginary line Y. The multiple second slits 50B may be located below the imaginary line Y. The imaginary line Y is an imaginary straight line extending in the second direction D2.

[0122] The first slit direction D3 of the first slit 50A may be inclined with respect to the second direction D2. For example, the first slit 50A may extend so as to be displaced upward as it moves away from the first side edge 11 in the second direction D2. The inclination angle θ1 of the first slit direction D3 with respect to the second direction D2 is, for example, 10° or more, may be 20° or more, or may be 30° or more. The inclination angle θ1 is, for example, 60° or less, may be 50° or less, or may be 40° or less.

[0123] The second slit direction D4 of the second slit 50B may be inclined with respect to the second direction D2. The second slit direction D4 may be different from the first slit direction D3. For example, the second slit 50B may extend so as to be displaced downward as it moves away from the first side edge 11 in the second direction D2. The inclination angle θ2 of the second slit direction D4 with respect to the second direction D2 is, for example, 10° or more, may be 20° or more, or may be 30° or more. The inclination angle θ2 is, for example, 60° or less, may be 50° or less, or may be 40° or less.

[0124] The first slit 50A and the second slit 50B may have the same length. For example, the difference between the length of the first slit 50A and the length of the second slit 50B may be 300 μm or less, 200 μm or less, or 100 μm or less. The first slit 50A and the second slit 50B may be formed at positions that are line-symmetrical to each other with respect to the virtual line Y.

[0125] 5, the multiple slit pairs may be disposed at equal intervals of a distance k2. The relationship between the dimension k1 of the slit 50 in the second direction D2 and the distance k2 is not necessarily limited, but it is preferable that the dimension k1 is greater than the distance k2 (k1>k2).

[0126] As shown in Figure 5, some of the first slits 50A may extend across the inner edge 5a1 of the lower portion 5a. Similarly, some of the second slits 50B may extend across the inner edge 5a1 of the lower portion 5a.

[0127] The cross-sectional structure of the slit 50 will be described. Fig. 6 is a cross-sectional view of the packaging material 40 cut along the slit direction at a position overlapping the slit 50. The slit direction is the first slit direction D3 or the second slit direction D4. The slit 50 may include a hole formed in the second base material layer 42. The slit 50 may not include a hole formed in a layer of the packaging material 40 other than the second base material layer 42.

[0128] The slit 50 may include a first non-penetrating portion 51, a penetrating portion 52, and a second non-penetrating portion 53. The first non-penetrating portion 51 and the second non-penetrating portion 53 are located on the outer surface of the second base material layer 42 and include recesses that do not penetrate the second base material layer 42. The first non-penetrating portion 51 and the second non-penetrating portion 53 are aligned in the slit direction. The penetrating portion 52 includes a hole that penetrates the second base material layer 42. The penetrating portion 52 is located between the first non-penetrating portion 51 and the second non-penetrating portion 53 in the slit direction.

[0129] The first non-penetrating portion 51 may include a first end 501 of the slit 50 in the slit direction. The depth of the recess in the first non-penetrating portion 51 may increase from the first end 501 toward the penetrating portion 52. As shown in Fig. 6, the contour of the bottom of the recess in the first non-penetrating portion 51 may be curved. Although not shown, the contour of the bottom of the recess in the first non-penetrating portion 51 may be linear.

[0130] The second non-penetrating portion 53 may include the second end 502 of the slit 50 in the slit direction. The depth of the recess in the second non-penetrating portion 53 may increase from the second end 502 toward the penetrating portion 52. As shown in Fig. 6, the contour of the bottom of the recess in the second non-penetrating portion 53 may be curved. Although not shown, the contour of the bottom of the recess in the second non-penetrating portion 53 may be linear.

[0131] The length r1 of the slit 50 is the sum of the length r2 of the first non-penetrating portion 51, the length r3 of the penetrating portion 52, and the length r4 of the second non-penetrating portion 53. That is, r1=r2+r3+r4. The ratio r3 / r1 of the length r3 to the length r1 is, for example, 0.3 or more, may be 0.4 or more, or may be 0.5 or more. The ratio r3 / r1 is, for example, 0.8 or less, may be 0.7 or less, or may be 0.6 or less. When the ratio r3 / r1 is 0.3 or more, the openability of the pouch 10 is improved. When the ratio r3 / r1 is 0.8 or less, the impact resistance of the pouch 10 is improved.

[0132] The length r1 of the slit 50 is, for example, 500 μm or more, may be 700 μm or more, or may be 1000 μm or more. The length r1 of the slit 50 is, for example, 5000 μm or less, may be 4000 μm or less, or may be 3000 μm or less.

[0133] <Adhesive details> As shown in FIG. 6, when the packaging material 40 includes the slit 50, the first adhesive layer 46 includes a portion that is not in contact with the second base material layer 42. In other words, the first adhesive layer 46 includes a portion that is not supported by the second base material layer 42. In this case, it is considered that stress is likely to be concentrated in the portion of the first adhesive layer 46 that is not supported by the second base material layer 42 when the packaging material 40 is deformed. The concentration of stress, for example, causes the first adhesive layer 46 to peel off. The peeling of the first adhesive layer 46 causes, for example, the first base material layer 41 to peel off from the second base material layer 42, that is, so-called delamination. The deformation of the packaging material 40 occurs, for example, when the pouch 10 is heated and the storage portion 71 expands.

[0134] Furthermore, the thickness of the portion of the first adhesive layer 46 that is not supported by the second base material layer 42 is likely to change when the packaging material 40 is heat-sealed.

[0135] Similarly, the second adhesive layer 47 also includes a portion that is not in contact with the second base layer 42. In this case, it is considered that stress is likely to be concentrated in the portion of the second adhesive layer 47 that is not supported by the second base layer 42 when the packaging material 40 is deformed, for example. The concentration of stress causes, for example, peeling of the second adhesive layer 47. Peeling of the second adhesive layer 47 causes, for example, peeling of the sealant layer 44 from the second base layer 42, so-called delamination.

[0136] Furthermore, the thickness of the portion of the second adhesive layer 47 that is not supported by the second base material layer 42 is likely to change when the packaging material 40 is heat-sealed.

[0137] As shown in the examples described later, the inventors have found that peeling of the first adhesive layer 46 and the second adhesive layer 47 can be suppressed by appropriately adjusting the softening points of the adhesive layers. The softening points of the first adhesive layer 46 and the second adhesive layer 47 are, for example, 225.0°C or higher, may be 230.0°C or higher, or may be 235.0°C or higher. The softening points of the first adhesive layer 46 and the second adhesive layer 47 are, for example, 280.0°C or lower, may be 270.0°C or lower, may be 260.0°C or lower, may be 250.0°C or lower, or may be 245.0°C or lower.

[0138] Only one of the first adhesive layer 46 and the second adhesive layer 47 may satisfy the above-mentioned numerical range for the softening point. For example, the first adhesive layer 46 may satisfy the above-mentioned numerical range for the softening point, but the second adhesive layer 47 may not satisfy the above-mentioned numerical range for the softening point. For example, the second adhesive layer 47 may satisfy the above-mentioned numerical range for the softening point, but the first adhesive layer 46 may not satisfy the above-mentioned numerical range for the softening point.

[0139] By setting the softening point of the adhesive layer to 280.0° C. or lower, it is possible to prevent delamination from occurring in a portion of the packaging material 40 when the pouch 10 is heated. By setting the softening point of the adhesive layer to 225.0° C. or higher, it is possible to prevent a change in the thickness of the adhesive layer when the packaging material 40 is heat-sealed.

[0140] The softening point of the adhesive layer is adjusted by adjusting the components of the main agent and the curing agent of the adhesive layer. For example, the smaller the weight average molecular weight Mw of the cured product produced by the reaction of the main agent and the curing agent, the higher the softening point of the adhesive layer tends to be. This is because the smaller the weight average molecular weight Mw, the shorter the molecular chain of the polymer component in the cured product, and the denser the structure of the polymer component. Conversely, the larger the weight average molecular weight Mw of the cured product, the lower the softening point of the adhesive layer tends to be. This is because the larger the weight average molecular weight Mw, the longer the molecular chain of the polymer component in the cured product. In addition, the softening point of the adhesive layer also varies depending on the type of isocyanate compound constituting the curing agent. For example, the softening point of an adhesive layer formed using isophorone diisocyanate (IPDI) tends to be higher than that of an adhesive layer formed using hexamethylene diisocyanate (HDI). This is because the reactivity of isophorone diisocyanate (IPDI) with alcohol is higher than the reactivity of hexamethylene diisocyanate (HDI) with alcohol.

[0141] The softening point of the adhesive layer is measured by local thermal analysis, so-called nano-TA. Details of the local thermal analysis will be explained in the examples described later.

[0142] <Manufacturing method> Next, a method for producing the pouch 10 will be described.

[0143] A method for manufacturing the packaging material 40 will be described. The second base material layer 42 is prepared. Then, a processing step is performed to form a plurality of processed portions 55 in the second base material layer 42. For example, the blade of a rotary die is inserted into the outer surface of the second base material layer 42 to form a plurality of processed portions 55 in the second base material layer 42. The processing step is performed on the second base material layer 42 being transported along the flow direction. The plurality of processed portions 55 are formed at predetermined intervals in the second base material layer 42 along a predetermined linear virtual line Y.

[0144] A first substrate layer 41 is prepared. As shown in FIG. 3, the first substrate layer 41 provided with a printed layer 45 may be prepared. As shown in FIG. 4, the first substrate layer 41 provided with a vapor deposition layer 48, a coating layer 49, and a printed layer 45 may be prepared. Then, a first lamination process is performed in which the first substrate layer 41 and the second substrate layer 42 are bonded together via a first adhesive layer 46. The first substrate layer 41 and the second substrate layer 42 are bonded together such that the inner surface of the first substrate layer 41 and the outer surface of the second substrate layer 42 face each other.

[0145] In the first lamination step, a coating step is performed in which an adhesive composition is applied to one of the two films to be bonded. If the adhesive composition contains a solvent, a drying step is performed after the coating step in which the adhesive composition is dried to volatilize the solvent. Then, a lamination step is performed in which the two films are laminated via the adhesive composition. Then, an aging step is performed in which the roll on which the two laminated films are wound is aged. The temperature of the aging step is, for example, 20°C or higher, and the time of the aging step is, for example, 24 hours or more.

[0146] A sealant layer 44 is prepared. Then, a second lamination process is performed in which the laminate including the first base material layer 41 and the second base material layer 42 and the sealant layer 44 are bonded together via a second adhesive layer 47. In the second lamination process, similarly to the first lamination process, a coating process, a drying process, a lamination process, an aging process, and the like are performed. As a result, a packaging material 40 shown in FIG. 3 or FIG. 4 is obtained.

[0147] A method for manufacturing a pouch 10 using a packaging material 40 will be described. The above-mentioned packaging material 40 including a plurality of processed portions 55 may be used as the front film 1 and the back film 2. A packaging material 40 including a second base material layer 42 on which a plurality of processed portions 55 are not formed may be used as the bottom film 3.

[0148] The bottom film 3, folded back at the fold-in portion 3a, is inserted between the inner surface of the front film 1 and the inner surface of the back film 2. Next, the front film 1, the back film 2, and a portion of the bottom film 3 are heat-sealed to form seal portions such as the first side seal portion 5, the second side seal portion 6, the bottom seal portion 7, and the isolation seal portion 20b. The heat-sealing temperature is, for example, 160°C or higher, may be 170°C or higher, or may be 180°C or higher. The heat-sealing temperature is, for example, 250°C or lower, may be 240°C or lower, or may be 230°C or lower.

[0149] The front film 1, back film 2, and bottom film 3, which have been joined together by thermal welding, are cut into an appropriate shape. This makes it possible to obtain the pouch 10 shown in FIG. 1. Next, the contents are filled into the pouch 10 through the opening 15 at the upper edge 14. After that, the inner surface of the front film 1 and the inner surface of the back film 2 are thermally welded along the upper edge 14 to form the upper seal portion 4. In this way, it is possible to obtain the pouch 10 in which the contents are contained and sealed, as shown in FIG. 7. Thereafter, the pouch 10 may be subjected to a sterilization treatment such as boiling or retort treatment.

[0150] <How to use> A user heats the pouch 10 using a microwave oven. The moisture contained in the contents evaporates, increasing the pressure in the storage section 71. When the pressure in the storage section 71 increases, the pouch 10 expands, for example, in a circular shape around the center point C of the storage section 71. Therefore, a force is applied to each position of the sealed section of the pouch 10 in a direction from the center point C toward the sealed section. When the force applied to the isolation seal section 20b exceeds a predetermined value, the separation of the isolation seal section 20b proceeds to peel off. When the separation of the isolation seal section 20b reaches the unsealed section 20a, the unsealed section 20a is connected to the storage section 71. The steam in the storage section 71 is discharged to the outside of the pouch 10 through the unsealed section 20a. This suppresses the increase in pressure in the storage section 71.

[0151] 8 and 9 are cross-sectional views showing the state of the pouch 10 during heating. As shown in FIG. 8 and FIG. 9, as the pressure in the storage section 71 increases, the distance between the front film 1 and the back film 2 in the storage section 71 increases. That is, the packaging material 40 located in the storage section 71 is displaced in the thickness direction of the pouch 10. On the other hand, the displacement of the packaging material 40 in the thickness direction does not occur in the sealed section such as the lower portion 5a of the first side seal section 5. Therefore, the packaging material 40 is significantly deformed at the boundary between the sealed section and the storage section 71. For example, as shown in FIG. 9, the packaging material 40 is deformed, such as bent, at the position of the inner edge 5a1 of the lower portion 5a.

[0152] In the deformed portion of the packaging material 40, stress is concentrated in each layer of the packaging material 40. In the present embodiment, the first adhesive layer 46 and the second adhesive layer 47 of the packaging material 40 have a softening point of 280.0° C. or less. Therefore, when the pouch 10 is heated, the first adhesive layer 46 and the second adhesive layer 47 are appropriately softened. The softening of the first adhesive layer 46 and the second adhesive layer 47 can relieve the stress generated in the deformed portion of the packaging material 40. This can suppress the occurrence of delamination in the deformed portion of the packaging material 40.

[0153] After heating the pouch 10, a user opens the pouch 10 by tearing the pouch 10 in the second direction D2. The pouch 10 includes an opening means 18 that extends across the receiving portion 71 from the first side seal 5 to the second side seal 6. A user can easily open the pouch 10 by tearing the pouch 10 along the opening means 18.

[0154] The opening means 18 is located below the steam release mechanism 20. This makes it possible to shorten the distance in the first direction D1 between the opening of the pouch 10 after opening and the upper surface of the contents. A user can easily remove the contents from the opening. For example, a user can remove the contents from the pouch 10 using cutlery such as a spoon.

[0155] FIG. 10 is a cross-sectional view showing the state of the pouch 10 when heated in a comparative embodiment. In the comparative embodiment, the packaging material 40 of the pouch 10 has a softening point higher than 280.0° C. For this reason, the first adhesive layer 46 and the second adhesive layer 47 cannot be sufficiently softened when the pouch 10 is heated. Since the stress generated in the deformed portion of the packaging material 40 is not relieved, it is considered that delamination occurs in the deformed portion of the packaging material 40. For example, as shown by the reference numeral 461 in FIG. 10, it is considered that the first adhesive layer 46 around the slit 50 peels off from the second base material layer 42. The influence of such peeled portion 461 appears on the outer surface of the packaging material 40 as deformation such as lifting and wrinkles.

[0156] According to this embodiment, the first adhesive layer 46 and the second adhesive layer 47 have a softening point of 280.0° C. or less, which can suppress delamination of the packaging material 40. This can suppress deformation such as lifting and wrinkles on the outer surface of the packaging material 40.

[0157] 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.

[0158] Fig. 11 is a front view showing an example of a pouch 10. As shown in Fig. 11, the bottom of the pouch 10 does not have to have a set portion. In other words, the pouch 10 does not have to have a bottom film 3. For example, the bottom seal portion 7 of the pouch 10 may extend along the lower edge 13 and join the inner surface of the front film 1 and the inner surface of the back film 2 together. EXAMPLES

[0159] 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.

[0160] <Example 1> A biaxially oriented polyamide film having a thickness of 15 μm was prepared as the second base layer 42. Then, a plurality of processed portions 55 were formed on the outer surface of the second base layer 42 using a rotary die. The plurality of processed portions 55 included a plurality of first slits 50A and a plurality of second slits 50B. The slits 50A and 50B included the above-mentioned first non-penetrating portion 51, the penetrating portion 52, and the second non-penetrating portion 53. The length r1 of the slits 50A and 50B was 1042.6 μm. The length r2 of the first non-penetrating portion 51 was 315.1 μm. The length r3 of the penetrating portion 52 was 333.3 μm. The length r4 of the second non-penetrating portion 53 was 395.4 μm. The ratio r3 / r1 was 0.320. The inclination angle θ1 of the first slit 50A was 24.4°. The inclination angle θ2 of the second slit 50B was 24.4°.

[0161] A first substrate layer 41 was prepared, which was provided with a vapor deposition layer 48 containing silicon oxide, a coating layer 49, and a printing layer 45. The first substrate layer 41 was a biaxially oriented polyethylene terephthalate film containing biomass-derived polyester and having a thickness of 12 μm. Next, a first lamination step was performed in which the first substrate layer 41 and the second substrate layer 42 were bonded together via a first adhesive layer 46. The amount of adhesive applied in the application step of the first lamination step was 4.0 g / m. 2 It was.

[0162] An unstretched polypropylene film with a thickness of 60 μm was prepared as the sealant layer 44. The sealant layer 44 was the second type sealant layer described above. Then, a second lamination step was carried out in which the laminate including the first base material layer 41 and the second base material layer 42 and the sealant layer 44 were bonded together via the second adhesive layer 47. This resulted in the packaging material 40 shown in FIG. 4 being obtained. The amount of adhesive applied in the application step of the second lamination step was 3.5 g / m. 2 It was.

[0163] Details of the adhesives for the first adhesive layer 46 and the second adhesive layer 47 were as follows: Type: Solvent-based adhesive Base material: polyester polyurethane resin Hardener: A mixture of isophorone diisocyanate (IPDI) trimer and xylylene diisocyanate (XDI) trimethylolpropane (TMP) adduct. Molar ratio of isocyanate group (NCO) of hardener to hydroxyl group (OH) of base material (NCO / OH): 4 Weight average molecular weight of base material: Mw: 30,000 ·Softening point: 244.5℃

[0164] A method for measuring the softening point of the adhesive of the first adhesive layer 46 will be described with reference to FIGS.

[0165] As shown in FIG. 12, a sample 65 is prepared in which a cross section 403 of the packaging material 40 is exposed. Although not shown, the sample 65 is embedded in resin. The process of preparing the sample 65 includes a step of cutting out the packaging material 40 of the pouch 10, a step of embedding the cut-out packaging material 40 in resin to prepare a block, and a step of cutting the block. The block is cut along a direction perpendicular to the outer surface 401 of the packaging material 40. This results in a cross section 403. The cutting is performed in an environment of 25° C. using a rotary microtome. The cross section 403 is then trimmed with a diamond knife. The thickness of each layer of the packaging material 40 is measured by observing the cross section 403 of the sample 65 using a scanning electron microscope. As the scanning electron microscope, an SU8000 manufactured by Hitachi, Ltd. is used.

[0166] The softening point was measured using a nanoTA manufactured by ANASYS INSTRUMENTS Co., Ltd. The thermal probe used was a PR-EX-AN2-300-5 manufactured by ANASYS INSTRUMENTS Co., Ltd.

[0167] Before the measurement, the following calibration was performed. NanoTA Calibration Samples manufactured by BRUKER were prepared as standard samples. The standard sample stages contained polycaprolactone (softening point: 55°C), polyethylene (softening point: 116°C), and polyethylene terephthalate (softening point: 235°C), all of which have known softening points. Each standard sample was heated while being brought into contact with a thermal probe on its surface. During heating, the thermal expansion directly below the thermal probe was measured, and a graph was obtained showing the deflection versus voltage. The measurement conditions set on the device were as follows: Measurement start temperature: 0.1V Measurement end temperature: 10V Heating rate: 0.5V / sec

[0168] Using the softening point of each standard sample, the graph showing the displacement of the thermal probe against the potential was converted into a graph showing the displacement against the temperature. In this manner, calibration (n=10) was performed.

[0169] After the calibration, the softening point of the first adhesive layer 46 was measured. The softening point was measured at a central portion in the thickness direction of the first adhesive layer 46 among the exposed portions of the cross section of the first adhesive layer 46. The measurement was performed at five or more locations on the same cross section. The measurement locations were determined so that the distance between two adjacent locations was 50 μm or more. The arithmetic average value of the measured values ​​at five locations that were measured with good reproducibility was adopted as the softening point of the first adhesive layer 46.

[0170] 12, the tip 61 of the thermal probe 60 is brought into contact with the cross section of the first adhesive layer 46. The tip 61 includes an element for locally heating the first adhesive layer 46. The heating conditions are as follows. Measurement start temperature: 40℃ End of measurement temperature: 350℃ Heating rate: 28℃ / sec

[0171] When the temperature of the tip portion 61 rises, the first adhesive layer 46 is locally heated. As shown in FIG. 13, when thermal expansion occurs in the heated portion of the first adhesive layer 46, the tip portion 61 is displaced upward. When the temperature of the tip portion 61 further rises, the first adhesive layer 46 softens due to melting or glass transition. As a result, the tip portion 61 penetrates into the expanded portion 462 of the first adhesive layer 46, as shown in FIG. 14.

[0172] FIG. 15 is a graph showing the displacement of the tip 61 in the up-down direction. The graph is also called a thermal expansion curve. The vertical axis shows the displacement of the tip 61, and the horizontal axis shows the temperature. When the first adhesive layer 46 softens, as shown in FIG. 15, if a peak appears in the thermal expansion curve, the temperature of the peak is adopted as the softening point Tf. If multiple peaks appear in the thermal expansion curve, the temperature of the peak that appears on the lowest temperature side is adopted as the softening point Tf. If a continuous displacement drop of 0.2 V or more is measured from the maximum displacement in the thermal expansion curve, it is considered that a peak has appeared.

[0173] The softening point of the second adhesive layer 47 is measured in the same manner as the softening point of the first adhesive layer 46 .

[0174] The pouch 10 in FIG. 1 was produced using the packaging material 40. The above-mentioned packaging material 40 including a plurality of processed portions 55 was used as the front film 1 and the back film 2. The packaging material 40 not including the processed portions 55 was used as the bottom film 3. The front film 1, the back film 2, and the bottom film 3 were heat-sealed to obtain the pouch 10. The pouch 10 was then filled with contents. The inner surface of the front film 1 and the inner surface of the back film 2 were heat-sealed along the upper edge 14 to obtain the pouch 10 in FIG. 7. The contents were 200 g of pork soup.

[0175] The dimensions of each part of the pouch 10 were as follows: Dimension S1 of pouch 10 in first direction D1: 147 mm Dimension S2 of pouch 10 in second direction D2: 160 mm Distance L3 from fold-in portion 3a to bottom edge 13: 46 mm Widths W1, W4 of lower parts 5a, 6a: 6mm Width W2, W5 of upper part 5b, 6b: 10mm

[0176] The heat welding 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

[0177] Next, the pouch 10 was subjected to a retort treatment under the following conditions. Method: Spray type Retort temperature: 121℃ Retort time: 30 minutes

[0178] Next, the pouch 10 was placed in a microwave oven so that it could stand on its own. Next, the pouch 10 was heated for 4 minutes in a microwave oven with an output of 600 W. The microwave oven used was a RE-TS3 manufactured by SHARP. Evaluations 1 and 2 were performed on the pouch 10 after heating.

[0179] (Rating 1) A portion of the surface film 1 of the pouch 10 after heating was cut out to prepare a rectangular sample. The sample included the lower portion 5a of the first side seal portion 5 and the storage portion 71. An image of the cross section of the sample was then obtained using an optical microscope. Based on the image, the thicknesses of the first adhesive layer 46 and the second adhesive layer 47 at the position overlapping with the slit 50 were calculated. The thickness of the adhesive layer in the pouch 10 after heating is also referred to as the second thickness. The second thickness was calculated by averaging the thicknesses of the first adhesive layer 46 and the second adhesive layer 47 in five samples.

[0180] The difference between the first thickness and the second thickness was evaluated. The first thickness is the thickness of the first adhesive layer 46 and the second adhesive layer 47 of the packaging material 40 before being processed into the pouch 10. The first thickness is calculated by averaging the thicknesses of the first adhesive layer 46 and the second adhesive layer 47 in five samples. Based on the difference between the first thickness and the second thickness, the evaluation results are classified into A, B, and C. "A" means that the difference between the first thickness and the second thickness is less than 1.0 μm. "B" means that the difference between the first thickness and the second thickness is 1.0 μm or more and 2.0 μm or less. "C" means that the difference between the first thickness and the second thickness is 2.0 μm or more. In Example 1, the result of Evaluation 1 was A.

[0181] (Rating 2) The surface of the surface film 1 of the pouch 10 after heating was observed to visually check whether any deformation such as lifting or wrinkles due to delamination had occurred. In particular, the surface of the surface film 1 overlapping the opening means 18 was visually observed. The evaluation results were classified into A and C based on whether any deformation had occurred. "A" means that no deformation had occurred on the surface of the surface film 1 overlapping the opening means 18. "C" means that deformation had occurred on the surface of the surface film 1 overlapping the opening means 18. In Example 1, the result of Evaluation 1 was A.

[0182] <Example 2> In the same manner as in Example 1, a packaging material 40 and a pouch 10 were prepared, and evaluations 1 and 2 were performed. Except for the first adhesive layer 46 and the second adhesive layer 47, the packaging material 40 and the pouch 10 of Example 2 were the same as the packaging material 40 and the pouch 10 of Example 1.

[0183] Details of the adhesives for the first adhesive layer 46 and the second adhesive layer 47 were as follows: Type: Solvent-based adhesive Base material: polyester polyurethane resin Hardener: Xylylene diisocyanate (XDI) trimethylolpropane (TMP) adduct Molar ratio of isocyanate group (NCO) of hardener to hydroxyl group (OH) of base material (NCO / OH): 4 Weight average molecular weight of base material: Mw: 30,000 ·Softening point: 235.8℃

[0184] The result of evaluation 1 was a B. The result of evaluation 2 was an A.

[0185] <Example 3> In the same manner as in Example 1, a packaging material 40 and a pouch 10 were prepared, and evaluations 1 and 2 were performed. Except for the first adhesive layer 46 and the second adhesive layer 47, the packaging material 40 and the pouch 10 of Example 3 are the same as the packaging material 40 and the pouch 10 of Example 1.

[0186] Details of the adhesives for the first adhesive layer 46 and the second adhesive layer 47 were as follows: Type: Solvent-free adhesive Base material: polyester resin Hardener: A mixture of hexamethylene diisocyanate (HDI) and xylylene diisocyanate (XDI) · Molar ratio of isocyanate group (NCO) of hardener to hydroxyl group (OH) of base material (NCO / OH): 2 Weight average molecular weight of base material: Mw: 4000 ·Softening point: 230.1℃

[0187] The result of evaluation 1 was a B. The result of evaluation 2 was an A.

[0188] <Comparative Example 1> In the same manner as in Example 1, a packaging material 40 and a pouch 10 were produced, and evaluations 1 and 2 were carried out. Except for the first adhesive layer 46 and the second adhesive layer 47, the packaging material 40 and the pouch 10 of Comparative Example 1 were the same as the packaging material 40 and the pouch 10 of Example 1.

[0189] Details of the adhesives for the first adhesive layer 46 and the second adhesive layer 47 were as follows: Type: Solvent-based adhesive Base material: polyester resin Hardener: A mixture of hexamethylene diisocyanate (HDI) biuret and HDI nurate. · Molar ratio of isocyanate group (NCO) of hardener to hydroxyl group (OH) of base material (NCO / OH): 2 Weight average molecular weight of base material: Mw: 22000 ·Softening point: 220.3℃

[0190] The result of evaluation 1 was a C. The result of evaluation 2 was an A.

[0191] <Comparative Example 2> In the same manner as in Example 1, a packaging material 40 and a pouch 10 were prepared, and evaluations 1 and 2 were performed. Except for the first adhesive layer 46 and the second adhesive layer 47, the packaging material 40 and the pouch 10 of Comparative Example 2 were the same as the packaging material 40 and the pouch 10 of Example 1.

[0192] Details of the adhesives for the first adhesive layer 46 and the second adhesive layer 47 were as follows: Type: Solvent-free adhesive Base material: polyester resin Hardener: A mixture of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) · Molar ratio of isocyanate group (NCO) of hardener to hydroxyl group (OH) of base material (NCO / OH): 2 Weight average molecular weight of base material: Mw: 3500 ·Softening point: 288.3℃

[0193] The result of evaluation 1 was an A. The result of evaluation 2 was a C.

[0194] The softening points of the adhesives in Examples 1 to 3 and Comparative Examples 1 and 2, and the results of Evaluation 1 and Evaluation 2 are shown in FIG.

[0195] When the softening point was 230.0°C or higher, the result of Evaluation 1 was A or B. In particular, when the softening point was 240.0°C or higher, the result of Evaluation 1 was A. On the other hand, in Comparative Example 1, since the softening point was low, the result of Evaluation 1 was C. It is believed that in Comparative Example 1, the adhesive softened during the heat welding process, causing the thickness of the adhesive layer to decrease.

[0196] When the softening point was 245.0°C or lower, the result of Evaluation 2 was A. On the other hand, in Comparative Example 1, the result of Evaluation 2 was C because the softening point was high. In Comparative Example 2, it is believed that the stress generated in the deformed portion of the packaging material 40 when the pouch 10 was heated could not be adequately alleviated, which caused delamination. When delamination occurs, the force applied to the packaging material 40 for opening is dispersed, reducing the ease of opening. [Explanation of symbols]

[0197] 1 Surface film 2 Back film 3 Bottom film 3a Folding part 3b~3e Second cutout 3f Bottom film part 1 3g Second part of bottom film 4 Upper seal part 5 First side seal 6 Second side seal 7 Bottom seal 7a First bottom seal 7b Second bottom seal 9 Bottom gusset 11 1st side edge 12 Second side edge 13 Lower edge 14 Upper edge 15 Opening 18 Opening Method 20 Steam release mechanism 21 Aperture 20a Unsealed part 20b Isolation seal part 22 First Edge 23 The Second Edge 24 The Third Edge 40 Packaging materials 41 1st base layer 42 Second base layer 44 Sealant Layer 45 Printing layer 46 First adhesive layer 461 Peeling part 462 Expanded part 47 Second adhesive layer 48 Deposited layer 49 Coating Layer 50 Slit 50A First Slit 50B 2nd slit 501 1st end 502 2nd end 51 1st non-penetrating part 52 Penetration 53 2nd non-penetrating part 55 Processing Department 71 Storage unit

Claims

1. A packaging material comprising, in order from an outer surface side to an inner surface side, at least a first base material layer, a first adhesive layer, a second base material layer, a second adhesive layer, and a sealant layer, The first substrate layer and the second substrate layer include a biaxially oriented plastic film, The second base material layer includes a plurality of processed portions including portions penetrating the second base material layer, The packaging material, wherein the first adhesive layer has a softening point of 230.0°C or higher and 245.0°C or lower.

2. The packaging material according to claim 1 , wherein the second adhesive layer has a softening point of 230.0° C. or higher and 245.0° C. or lower.

3. The packaging material according to claim 2 , wherein the first adhesive layer and the second adhesive layer contain a cured product of a polyol and an isocyanate compound.

4. The packaging material of claim 3 , wherein the polyol comprises a polyester polyol.

5. The packaging material according to any one of claims 1 to 4, wherein the plurality of processed portions include a plurality of slits extending in a slit direction.

6. The packaging material according to claim 5 , wherein the slit has a length of 500 μm or more in the slit direction.

7. The slit is A first non-penetrating portion and a second non-penetrating portion are located on an outer surface of the second base material layer, include a recess that does not penetrate the second base material layer, and are aligned in the slit direction; The packaging material according to claim 5 , further comprising: a through portion that is located between the first non-penetrating portion and the second non-penetrating portion in the slit direction and that penetrates the second base material layer.

8. The packaging material according to claim 5 , wherein the plurality of processed portions include a plurality of first slits extending in a first slit direction and a plurality of second slits extending in a second slit direction different from the first slit direction.

9. The packaging material according to any one of claims 1 to 4, wherein the sealant layer comprises 80% by mass or more of block polypropylene, an elastomer, and polyethylene.

10. The packaging material according to claim 9, wherein the elastomer comprises an ethylene-α-olefin copolymer.

11. The first base layer comprises polyester, The packaging material according to any one of claims 1 to 4, wherein the second substrate layer comprises polyamide.

12. A pouch in which a storage section for storing contents is defined between a front film and a back film, a seal portion that joins the sealant layer of the front surface film and the sealant layer of the back surface film; and an opening means including a plurality of the processed portions of the front surface film and a plurality of the processed portions of the back surface film, The front surface film and the back surface film include the packaging material according to any one of claims 1 to 4, The seal portion includes a first side seal portion located on a first side edge of the pouch, and a second side seal portion located on a second side edge of the pouch opposite to the first side edge, and defining the containing portion between the first side seal portion and the second side seal portion, The opening means extends across the container from the first side seal to the second side seal.

13. Further comprising a bottom film positioned between the front film and the back film, The pouch of claim 12, wherein the sealing portion further includes a first bottom sealing portion located at a lower edge of the pouch and joining the inner surface of the surface film to the inner surface of the bottom film and the inner surface of the back film to the inner surface of the bottom film.

14. 13. The pouch of claim 12 comprising a steam venting mechanism.

15. 15. The pouch of claim 14, wherein the opening means is located below the steam venting mechanism.

16. 15. The pouch of claim 14, wherein the vapor venting mechanism includes an isolating seal portion and an unsealed portion isolated from the containing portion by the isolating seal portion.

17. 17. The pouch of claim 16, wherein the unsealed portion extends to reach the first side edge.

Images