Packaging material and retort pouch or microwave pouch provided with the packaging material

Abstract

The packaging material comprises, in order from the outer surface to the inner surface, at least a first stretched plastic film, a second stretched plastic film, and a sealant layer. The only stretched plastic films contained in the packaging material are the first stretched plastic film and the second stretched plastic film. One of the first stretched plastic film or the second stretched plastic film is a high-stiffness polyester film, and the other of the first stretched plastic film or the second stretched plastic film contains polyester as a primary component. The loop stiffness in one direction of the packaging material is 0.16 N or greater.

Description

[Technical Field]

[0001] The present invention relates to packaging materials and packaging products, such as retort pouches or microwaveable pouches, comprising the packaging materials. [Background technology]

[0002] Various packaging materials have been developed and proposed for use in packaging products such as bags and containers for filling and packaging various items, including food and beverages, pharmaceuticals, chemicals, cosmetics, sanitary products, daily necessities, and the like. The packaging materials are composed of a laminate including at least one stretched plastic film and a sealant layer for welding together the packaging materials. For example, Patent Document 1 proposes the use of a stretched polyethylene terephthalate film, a silica-deposited stretched polyethylene terephthalate film, an alumina-deposited stretched polyethylene terephthalate film, a stretched nylon film, a stretched polypropylene film, a polypropylene / ethylene-vinyl alcohol copolymer co-extruded co-stretched film, or a composite film formed by laminating two or more of these films as the packaging material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-120550 DISCLOSURE OF THE INVENTION

[0004] Packaging materials for constituting packaged products are required to have sufficient rigidity to prevent the packaged product from being torn even when a sharp member with a pointed tip comes into contact with the packaged product.

[0005] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a packaging material having rigidity.

[0006] One embodiment of the present invention is a packaging material comprising: A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first biaxially oriented plastic film, a second biaxially oriented plastic film, and a sealant layer, The biaxially oriented plastic films contained in the packaging material are only the first biaxially oriented plastic film and the second biaxially oriented plastic film, The sealant layer contains polypropylene as a main component, The packaging material has a loop stiffness in one direction of 0.160 N or more. In this case, the first biaxially oriented plastic film and the second biaxially oriented plastic film may contain polyester as a main component.

[0007] One embodiment of the present invention is a packaging material comprising: A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first biaxially oriented plastic film, a second biaxially oriented plastic film, and a sealant layer, The biaxially oriented plastic films contained in the packaging material are only the first biaxially oriented plastic film and the second biaxially oriented plastic film, The sealant layer contains polypropylene as a main component, The packaging material has a loop stiffness in one direction divided by the thickness of the packaging material of 0.00150 [N / μm] or more.

[0008] One embodiment of the present invention is a packaging material comprising: A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first biaxially oriented plastic film, a second biaxially oriented plastic film, and a sealant layer, One of the first biaxially oriented plastic film or the second biaxially oriented plastic film is a high-stiffness polyester film, and the other of the first biaxially oriented plastic film or the second biaxially oriented plastic film contains polyester or polyamide as a main component; The high-stiffness polyester film is a packaging material that has a loop stiffness of 0.0017 N or more in one direction and contains polyester as a main component.

[0009] One embodiment of the present invention is a packaging material comprising: A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first biaxially oriented plastic film, a second biaxially oriented plastic film, and a sealant layer, The first biaxially oriented plastic film and the second biaxially oriented plastic film each contain polyethylene terephthalate as a main component, The packaging material has a puncture strength of 14 N or more.

[0010] One embodiment of the present invention is a packaging material comprising: A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first biaxially oriented plastic film, a second biaxially oriented plastic film, and a sealant layer, One of the first biaxially oriented plastic film or the second biaxially oriented plastic film is a high-stiffness polyester film, and the other of the first biaxially oriented plastic film or the second biaxially oriented plastic film contains polyester or polyamide as a main component; The packaging material has a tensile strength divided by a tensile elongation of the high stiffness polyester film of 2.0 [MPa / %] or more in at least one direction.

[0011] In the packaging material according to one embodiment of the present invention, the packaging material may have a puncture strength of 14 N or more.

[0012] In the packaging material according to one embodiment of the present invention, the high stiffness polyester film may have a tensile strength of 250 MPa or more in one direction.

[0013] In one embodiment of the packaging material, either the first biaxially oriented plastic film or the second biaxially oriented plastic film may be a straight-cut film having a tensile strength in one direction greater than a tensile strength in a direction perpendicular to the one direction. In this case, the tensile strength of the straight-cut film in one direction may be 1.05 times or more the tensile strength of the straight-cut film in the direction perpendicular to the one direction.

[0014] The packaging material according to one embodiment of the present invention may comprise a printed layer.

[0015] In the packaging material according to one embodiment of the present invention, the sealant layer may contain polypropylene as a main component.

[0016] In the packaging material according to one embodiment of the present invention, the sealant layer may contain polyethylene having a melting point of 100°C or higher as a main component.

[0017] In a packaging material according to one embodiment of the present invention, the sealant layer may have a first layer mainly composed of polyethylene or polypropylene, and a second layer located on the inner side of the first layer and containing a mixed resin of polyethylene and polypropylene.

[0018] The packaging material according to one embodiment of the present invention may further comprise a vapor deposition layer located on either the first biaxially oriented plastic film or the second biaxially oriented plastic film, and a gas barrier coating film located on the vapor deposition layer.

[0019] One embodiment of the present invention is a retort pouch comprising the packaging material described above.

[0020] One embodiment of the present invention is a microwaveable pouch having a container, Steam-listed packaging materials and and a seal portion joining the inner surfaces of the packaging material together, the seal portion including a steam release seal portion that peels off due to an increase in pressure in the containing portion.

[0021] According to the present invention, a packaging material having rigidity can be provided. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a front view showing a bag according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the layer structure of a packaging material that constitutes a bag. [Figure 3] FIG. 10 is a cross-sectional view showing a modified example of the layer structure of the packaging material that constitutes the bag. [Figure 4] FIG. 10 is a cross-sectional view showing a modified example of the layer structure of the packaging material that constitutes the bag. [Figure 5] FIG. 1 is a plan view showing an example of a loop stiffness measuring device. [Figure 6] FIG. 6 is a cross-sectional view of the loop stiffness measuring device of FIG. 5 taken along line VI-VI. [Figure 7] FIG. 10 is a diagram showing an example of a method for preparing a test piece used in a loop stiffness measuring device. [Figure 8] FIG. 10 is a diagram illustrating a process of attaching a test piece to a loop stiffness measuring instrument. [Figure 9] FIG. 10 is a diagram illustrating a step of forming a loop portion in a test piece. [Figure 10] FIG. 10 is a diagram illustrating a process of applying a load to a loop portion of a test piece. [Figure 11] FIG. 10 is a diagram illustrating a process of applying a load to a loop portion of a test piece. [Figure 12] FIG. 2 is a diagram showing an example of a layer structure of a sealant layer. [Figure 13] FIG. 1 shows an example of the results of analyzing a transparent vapor-deposited layer formed on the surface of a stretched plastic film using a time-of-flight secondary ion mass spectrometer. [Figure 14]10A and 10B are diagrams showing an example of a method for filling a bag with contents. [Figure 15] FIG. 10 is a front view showing a modified example of the bag. [Figure 16] FIG. 10 is a front view showing a modified example of the bag. [Figure 17A] 1 is a longitudinal cross-sectional view showing an example of a container containing packaging material. [Figure 17B] FIG. 1 is a plan view illustrating an example of a container containing packaging material. [Figure 18] FIG. 10 is a cross-sectional view showing an example of a packaging material according to a second embodiment. [Figure 19] FIG. 10 is a cross-sectional view showing an example of a packaging material according to a second embodiment. [Figure 20] FIG. 1 is a cross-sectional view showing an example of a substrate of a barrier laminate film. [Figure 21] FIG. 2 is a cross-sectional view showing an example of a sealant layer. [Figure 22] FIG. 1 shows an example of the results of analyzing a vapor-deposited layer of a barrier laminate film using a time-of-flight secondary ion mass spectrometer. [Figure 23] FIG. 1 is a diagram illustrating an example of a film formation apparatus for forming a vapor deposition layer on a substrate. [Figure 24] FIG. 10 is a diagram showing an example of a method for measuring puncture strength. [Figure 25] FIG. 2 is a plan view showing a test piece for evaluating tearability. [Figure 26] FIG. 1 is a diagram showing the evaluation results of Examples A1 to A6 and Comparative Example A1. [Figure 27] FIG. 1 is a diagram showing the evaluation results of Examples A1 to A6 and Comparative Example A1. [Figure 28] FIG. 1 is a diagram showing the evaluation results of Examples A7 to A6 and Reference Examples A7 to A8. [Figure 29] FIG. 1 is a diagram showing the evaluation results of Examples C1 to C3. [Figure 30] FIG. 10 is a diagram showing the evaluation results of Reference Examples C4 to C9. [Figure 31] FIG. 1 is a diagram showing the evaluation results of Examples C1 to C3 and Reference Examples C4 to C9. DETAILED DESCRIPTION OF THE INVENTION

[0023] First embodiment An embodiment of the present invention will be described with reference to Figures 1 to 16. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding.

[0024] Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of lengths and angles, are not to be construed as being bound by strict meanings, but rather as including a range within which similar functions can be expected.

[0025] Fig. 1 is a front view showing bag 10 according to the present embodiment. Bag 10 includes a storage section 17 for storing contents. Fig. 1 shows bag 10 in a state before the contents are stored in it. The configuration of bag 10 will be described below.

[0026] bag In this embodiment, bag 10 is a gusset-type bag configured to be self-standing. Bag 10 includes an upper portion 11, a lower portion 12, and a pair of side portions 13, and has a generally rectangular outline in a front view. Note that names such as "upper portion," "lower portion," and "side portion," as well as terms such as "above" and "below," merely describe the relative positions and directions of bag 10 and its components, based on a state in which bag 10 is self-standing with the gusset portion facing downwards. The position of bag 10 during transportation or use is not limited by the names and terms used in this specification.

[0027] In this embodiment, the width direction of bag 10 is also referred to as first direction D1. The pair of side portions 13 described above face each other in first direction D1. The direction perpendicular to first direction D1 is also referred to as second direction D2. Bag 10 of this embodiment is intended to be used in such a way that a consumer tears bag 10 along first direction D1 to open bag 10.

[0028] 1, the bag 10 includes a surface film 14 that forms the surface, a back film 15 that forms the back, and a lower film 16 that forms the lower part 12. The lower film 16 is disposed between the surface film 14 and the back film 15 in a state where it is folded back at a folding portion 16f.

[0029] The terms "surface film," "back film," and "lower film" mentioned above merely distinguish each film according to its positional relationship, and the terms do not limit the method of providing the films when manufacturing bag 10. For example, bag 10 may be manufactured using one film in which surface film 14, back film 15, and lower film 16 are connected together, or may be manufactured using two films: one film in which surface film 14 and lower film 16 are connected together and one back film 15, or may be manufactured using three films: one surface film 14, one back film 15, and one lower film 16.

[0030] The inner surfaces of the front film 14, back film 15, and bottom film 16 are joined together by sealed portions. In a plan view of the bag 10 such as Figure 1, the sealed portions are hatched.

[0031] As shown in Figure 1, the seal portion has an outer edge seal portion that extends along the outer edge of bag 10. The outer edge seal portion includes a bottom seal portion 12a that extends to bottom 12, and a pair of side seal portions 13a that extend along a pair of side portions 13. Before contents are placed inside bag 10, as shown in Figure 1, top 11 of bag 10 forms opening 11b. After contents are placed inside bag 10, the inner surfaces of front film 14 and back film 15 are joined at top 11 to form top seal portion 11a (see Figure 7), thereby sealing bag 10.

[0032] The side seal portion 13a and the upper seal portion 11a are seal portions formed by joining the inner surface of the front film 14 and the inner surface of the back film 15. On the other hand, the lower seal portion 12a includes a seal portion formed by joining the inner surface of the front film 14 and the inner surface of the bottom film 16, and a seal portion formed by joining the inner surface of the back film 15 and the inner surface of the bottom film 16.

[0033] There are no particular limitations on the method for forming the seal portion, as long as it is possible to join opposing films together and seal bag 10. For example, the seal portion may be formed by melting the inner surfaces of the films by heating or the like, welding the inner surfaces together, i.e., by heat sealing. Alternatively, the seal portion may be formed by bonding the inner surfaces of opposing films together using an adhesive or the like.

[0034] Easy-to-open means The front film 14 and the back film 15 may be provided with easy-open means 25 for tearing the front film 14 and the back film 15 along the first direction D1 to open the bag 10. For example, as shown in Fig. 1, the easy-open means 25 may include a notch 26 formed in the side seal portion 13a of the bag 10, which serves as a starting point for tearing. Alternatively, the easy-open means 25 may be a half-cut line formed by laser processing, a cutter, or the like, in a portion that serves as a path for tearing the bag 10.

[0035] Furthermore, although not shown, the easy-open means 25 may include a group of cuts or scars formed in the area where the seal portion is formed of the front film 14 and the back film 15. The group of scars may include, for example, a plurality of through holes formed so as to penetrate the front film 14 and / or the back film 15. Alternatively, the group of scars may include a plurality of holes formed on the outer surface of the front film 14 and / or the back film 15 so as not to penetrate the front film 14 and / or the back film 15.

[0036] Layer structure of surface film and back film Next, a description will be given of the layer structure of the front film 14 and the back film 15. Fig. 2 is a cross-sectional view showing an example of the layer structure of a packaging material 30 that constitutes the front film 14 and the back film 15.

[0037] 2, the packaging material 30 includes at least a first stretched plastic film 40, a first adhesive layer 45, a second stretched plastic film 50, a second adhesive layer 55, and a sealant layer 70, in this order. The first stretched plastic film 40 is located on the outer surface 30y side, and the sealant layer 70 is located on the inner surface 30x side opposite the outer surface 30y. The inner surface 30x is the surface located on the storage section 17 side.

[0038] Each film constituting the packaging material 30, such as the first stretched plastic film 40, the second stretched plastic film 50, and the sealant layer 70, as well as the packaging material 30, has a machine direction and a vertical direction. The machine direction is the direction in which the film flows when formed, and is known as the MD (Machine Direction). The vertical direction is the direction perpendicular to the machine direction, and is known as the TD (Transverse Direction). In the bag 10 shown in FIG. 1, the direction in which the upper portion 11 and the lower portion 12 extend is the machine direction, and the direction in which the side portion 13 extends is the vertical direction.

[0039] The packaging material 30 of this embodiment is configured to have rigidity. This allows the bag 10 including the packaging material 30 to have rigidity. For example, it is possible to prevent the bag 10 from being torn when a sharp member with a pointed tip comes into contact with the bag 10. The thickness of the packaging material 30 is, for example, 80 μm or more, or may be 90 μm or more, 100 μm or more, or 105 μm or more. The thickness of the packaging material 30 may also be 140 μm or less, 130 μm or less, 120 μm or less, 115 μm or less, or 110 μm or less.

[0040] Each layer of packaging material 30 will now be described in detail.

[0041] (Stretched plastic film) The first stretched plastic film 40 and the second stretched plastic film 50 are both biaxially stretched plastic films stretched in two predetermined directions. The stretching direction of each stretched plastic film 40, 50 is not particularly limited. For example, the stretched plastic films 40, 50 may be stretched in the direction in which the side portions 13 extend, or in a direction perpendicular to the direction in which the side portions 13 extend. The stretching directions of each stretched plastic film 40, 50 may be the same or different. The stretching ratio of each stretched plastic film 40, 50 is, for example, 1.05 times or more.

[0042] In this embodiment, we propose using a stretched plastic film having a loop stiffness of 0.0017 N or more in at least one direction and containing polyester as a primary component as either the first stretched plastic film 40 or the second stretched plastic film 50. In the following description, a stretched plastic film having a loop stiffness of 0.0017 N or more in at least one direction and containing polyester as a primary component is also referred to as a high-stiffness polyester film. A high-stiffness polyester film may have a loop stiffness of 0.0017 N or more in at least one of the machine direction (MD) or the transverse direction (TD). A high-stiffness polyester film may have a loop stiffness of 0.0017 N or more in both the machine direction (MD) and the transverse direction (TD). By including a high-stiffness polyester film in the packaging material 30, the packaging material 30 can be made rigid. The polyester is preferably a polyester primarily composed of an aromatic polyester consisting of at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid and at least one aliphatic alcohol selected from ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Examples of polyesters include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). Examples of high-stiffness polyester films include high-stiffness PET films containing 51% by mass or more of PET as the main component, and high-stiffness PBT films containing 51% by mass or more of PBT as the main component. The thickness of the high-stiffness polyester film is preferably 5 μm or more, more preferably 7 μm or more. The thickness of the high-stiffness polyester film is preferably 25 μm or less, more preferably 20 μm or less.

[0043] Loop stiffness is a parameter that represents the stiffness of a film such as a stretched plastic film. A method for measuring loop stiffness will be described below with reference to FIGS. 5 to 11. The measurement method described below can be used not only for single-layer films such as stretched plastic films, but also for films with multiple layers such as vapor-deposited films and laminated films. A vapor-deposited film is a film that includes a single-layer film such as a stretched plastic film and a vapor-deposited layer formed on the single-layer film. A laminated film is a film that includes multiple laminated films, such as packaging material 30.

[0044] FIG. 5 is a plan view showing the test piece 80 and the loop stiffness measuring device 85, and FIG. 6 is a cross-sectional view of the test piece 80 and the loop stiffness measuring device 85 of FIG. 5 taken along line VI-VI. The test piece 80 is a rectangular film having long and short sides. In the present application, the length L1 of the long side of the test piece 80 is 150 mm, and the length L2 of the short side is 15 mm. As the loop stiffness measuring device 85, for example, No. 581 Loop Stiffness Tester (registered trademark) LOOP STIFFNESS TESTER DA type manufactured by Toyo Seiki Seisakusho, Ltd. can be used. The length L1 of the long side of the test piece 80 is adjustable as long as the test piece 80 can be gripped by a pair of chucks 86, which will be described later.

[0045] The loop stiffness measuring device 85 has a pair of chuck portions 86 for gripping a pair of ends in the long side direction of the test specimen 80, and a support member 87 for supporting the chuck portions 86. The chuck portions 86 include a first chuck 861 and a second chuck 862. In the state shown in FIGS. 5 and 6 , the test specimen 80 is placed on the pair of first chucks 861, and the second chuck 862 has not yet gripped the test specimen 80 between the first chuck 861 and the second chuck 862. As will be described later, during measurement, the test specimen 80 is gripped between the first chuck 861 and the second chuck 862 of the chuck portions 86. The second chuck 862 may be connected to the first chuck 861 via a hinge mechanism.

[0046] When a film to be measured, such as a stretched plastic film, a vapor-deposited film, or a laminated film, is available in a state before being processed into a packaging product, the test piece 80 may be prepared by cutting the film to be measured. Alternatively, the test piece 80 may be prepared by cutting a packaging product made from a packaging material 30, such as a bag, and removing the film to be measured. FIG. 7 shows an example of a method for preparing the test piece 80 by cutting the surface film 14 or the back film 15 of a bag 10. When measuring the loop stiffness of the packaging material 30 in the machine direction, the test piece is prepared by cutting the surface film 14 or the back film 15 of the bag 10 so that the long side direction of the test piece coincides with the machine direction, as shown by reference numeral 80A in FIG. 7. When measuring the loop stiffness of the packaging material 30 in the vertical direction, the test piece is prepared by cutting the surface film 14 or the back film 15 of the bag 10 so that the long side direction of the test piece coincides with the vertical direction, as shown by reference numeral 80B in FIG. 7.

[0047] A method for measuring the loop stiffness of the test piece 80 using the loop stiffness measuring device 85 will be described. First, as shown in FIGS. 5 and 6 , the test piece 80 is placed on a first chuck 861 of a pair of chucks 86 arranged with a gap L3 therebetween. In the present application, the gap L3 is set so that the length of a loop portion 81 (described later, also referred to as the loop length) is 60 mm. The test piece 80 includes an inner surface 80x located on the first chuck 861 side and an outer surface 80y located opposite the inner surface 80x. When the test piece 80 is made of a packaging material 30, the inner surface 80x and the outer surface 80y of the test piece 80 coincide with the inner surface 30x and the outer surface 30y of the packaging material 30. When a loop portion 81 (described later) is formed in the test piece 80, the inner surface 80x is located inside the loop portion 81, and the outer surface 80y is located outside the loop portion 81. Next, as shown in FIG. 8, the second chuck 862 is placed on the test piece 80 so that the end of the long side of the test piece 80 is gripped between the first chuck 861 and the second chuck 862.

[0048] Next, as shown in FIG. 9 , at least one of the pair of chuck portions 86 is slid on the support member 87 in a direction that reduces the distance between the pair of chuck portions 86. This allows a loop portion 81 to be formed on the test piece 80. The test piece 80 shown in FIG. 9 has a loop portion 81, a pair of intermediate portions 82, and a pair of fixing portions 83. The pair of fixing portions 83 are portions of the test piece 80 that are gripped by the pair of chuck portions 86. The pair of intermediate portions 82 are portions of the test piece 80 that are located between the loop portion 81 and the pair of intermediate portions 82. As shown in FIG. 9 , the chuck portion 86 is slid on the support member 87 until the inner surfaces 80x of the pair of intermediate portions 82 come into contact with each other. This allows a loop portion 81 having a loop length of 60 mm to be formed. The loop length of the loop portion 81 is the length of the test piece 80 between position P1 where the surface of one second chuck 862 on the loop portion 81 side intersects with the test piece 80, and position P2 where the surface of the other second chuck 862 on the loop portion 81 side intersects with the test piece 80. If the thickness of the test piece 80 is ignored, the above-mentioned distance L3 is the value obtained by adding 2×t to the length of the loop portion 81, where t is the thickness of the second chuck 862 of the chuck portion 86.

[0049] Then, as shown in FIG. 10 , the posture of the chuck portion 86 is adjusted so that the protruding direction Y of the loop portion 81 relative to the chuck portion 86 is horizontal. For example, the posture of the chuck portion 86 supported by the support member 87 is adjusted by moving the support member 87 so that the normal direction of the support member 87 is horizontal. In the example shown in FIG. 10 , the protruding direction Y of the loop portion 81 coincides with the thickness direction of the chuck portion. Furthermore, a load cell 88 is prepared at a position a distance Z1 away from the second chuck 862 in the protruding direction Y of the loop portion 81. In this application, the distance Z1 is set to 50 mm. Next, the load cell 88 is moved toward the loop portion 81 of the test piece 80 at a speed V by a distance Z2 shown in FIG. 10 . The distance Z2 is set so that the load cell 88 contacts the loop portion 81 and then pushes the loop portion 81 toward the chuck portion 86, as shown in FIGS. 10 and 11 . In this application, the distance Z2 is set to 40 mm. In this case, the distance Z3 between the load cell 88 and the second chuck 862 of the chuck portion 86 is 10 mm when the load cell 88 is pressing the loop portion 81 toward the chuck portion 86. The speed V at which the load cell 88 is moved is 3.3 mm / sec.

[0050] Next, as shown in Fig. 11, the load cell 88 is moved a distance Z2 toward the chuck portion 86, and in a state where the load cell 88 is pressing into the loop portion 81 of the test piece 80, the value of the load applied to the load cell 88 from the loop portion 81 becomes stable, and then the value of the load is recorded. The value of the load thus obtained is used as the loop stiffness of the film constituting the test piece 80. In this application, unless otherwise specified, the environment during measurement of loop stiffness is a temperature of 23°C and a relative humidity of 50%.

[0051] The preferred mechanical properties of the high stiffness polyester film will be further described. The puncture strength of the high stiffness polyester film is preferably 10 N or more, and more preferably 11 N or more.

[0052] The tensile strength of the high-stiffness polyester film in at least one direction is preferably 250 MPa or more, more preferably 280 MPa or more. For example, the tensile strength of the high-stiffness polyester film in the machine direction is preferably 250 MPa or more, more preferably 280 MPa or more. The tensile strength of the high-stiffness polyester film in the perpendicular direction is preferably 250 MPa or more, more preferably 280 MPa or more. The tensile elongation of the high stiffness polyester film in at least one direction is preferably 130% or less, more preferably 120% or less. For example, the tensile elongation of the high stiffness polyester film in the machine direction is preferably 130% or less, more preferably 120% or less. The tensile elongation of the high stiffness polyester film in the perpendicular direction is preferably 120% or less, more preferably 110% or less. Preferably, the tensile strength of the high-stiffness polyester film divided by the tensile elongation in at least one direction is 2.0 [MPa / %] or more. For example, the tensile strength of the high-stiffness polyester film divided by the tensile elongation in the transverse direction (TD) is preferably 2.0 [MPa / %] or more, more preferably 2.2 [MPa / %] or more. The tensile strength of the high-stiffness polyester film divided by the tensile elongation in the machine direction (MD) is preferably 1.8 [MPa / %] or more, more preferably 2.0 [MPa / %] or more. The tensile strength and tensile elongation can be measured in accordance with JIS K7127. A tensile tester STA-1150 manufactured by Orientec Co., Ltd. can be used as a measuring instrument. A rectangular film 15 mm wide and 150 mm long cut from a high-stiffness polyester film can be used as a test piece. The distance between the pair of chucks holding the test piece at the start of measurement is 100 mm, and the tensile speed is 300 mm / min. In this application, unless otherwise specified, the environment during measurement of tensile strength and tensile elongation is a temperature of 23°C and a relative humidity of 50%.

[0053] The heat shrinkage of the high stiffness polyester film in at least one direction is preferably 0.7% or less, more preferably 0.5% or less. For example, the heat shrinkage of the high stiffness polyester film in the machine direction is preferably 0.7% or less, more preferably 0.5% or less. The heat shrinkage of the high stiffness polyester film in the perpendicular direction is preferably 0.7% or less, more preferably 0.5% or less. The heating temperature for measuring the heat shrinkage is 100°C, and the heating time is 40 minutes. The tensile modulus of the high stiffness polyester film in at least one direction is preferably 4.0 GPa or more, more preferably 4.5 MPa or more. For example, the tensile modulus of the high stiffness polyester film in the machine direction is preferably 4.0 GPa or more, more preferably 4.5 MPa or more. The tensile modulus of the high stiffness polyester film in the perpendicular direction is preferably 4.0 GPa or more, more preferably 4.5 GPa or more.

[0054] In the manufacturing process of a high-stiffness polyester film, for example, a plastic film obtained by melting and molding a polyester is first stretched 3 to 4.5 times in both the machine direction and the perpendicular direction at 90 to 145°C in a first stretching step. This is followed by a second stretching step in which the plastic film is stretched 1.1 to 3.0 times in both the machine direction and the perpendicular direction at 100 to 145°C in a second stretching step. This is followed by heat setting at 190 to 220°C. This is followed by relaxation treatment (treatment to reduce the film width) at 100 to 190°C in both the machine direction and the perpendicular direction at approximately 0.2 to 2.5%. By adjusting the stretch ratio, stretching temperature, heat setting temperature, and relaxation treatment rate in these steps, a high-stiffness polyester film having the above-mentioned mechanical properties can be obtained.

[0055] According to this embodiment, the packaging material 30 includes a high-stiffness polyester film, thereby increasing the loop stiffness of the packaging material 30. The loop stiffness of the packaging material 30 in at least one direction is, for example, 0.160 N or more, or may be 0.165 N or more, or 0.170 N or more, or 0.175 N or more, or 0.180 N or more. For example, the loop stiffness of the packaging material 30 in the machine direction (MD) is, for example, 0.160 N or more, or may be 0.165 N or more, or 0.170 N or more, or 0.175 N or more, or 0.180 N or more. Furthermore, the loop stiffness of the packaging material 30 in the transverse direction (TD) is, for example, 0.160 N or more, or may be 0.165 N or more, or 0.170 N or more, or 0.175 N or more, or 0.180 N or more.

[0056] Furthermore, according to the present embodiment, the packaging material 30 includes a high-stiffness polyester film, thereby increasing the loop stiffness of the packaging material 30 per unit thickness of the packaging material 30. The value obtained by dividing the loop stiffness of the packaging material 30 in at least one direction by the thickness of the packaging material 30 is, for example, 0.00150 N / μm or more, or may be 0.00155 N / μm or more, or 0.00160 N / μm or more, or 0.00165 N / μm or more, or 0.00170 N / μm or more. For example, the value obtained by dividing the loop stiffness of the packaging material 30 in the machine direction (MD) by the thickness of the packaging material 30 is, for example, 0.00150 N / μm or more, or 0.00155 N / μm or more, or 0.00160 N / μm or more, or 0.00165 N / μm or more, or 0.00170 N / μm or more. Furthermore, the value obtained by dividing the loop stiffness of the packaging material 30 in the vertical direction (TD) by the thickness of the packaging material 30 is, for example, 0.00150 N / μm or more, or alternatively 0.00155 N / μm or more, or 0.00160 N / μm or more, or 0.00165 N / μm or more, or alternatively 0.00170 N / μm or more.

[0057] When the high-stiffness polyester film is a high-stiffness PET film containing PET as a main component, the PET constituting the high-stiffness PET film may contain biomass-derived PET. In this case, the high-stiffness PET film may be composed solely of biomass-derived PET. Alternatively, the high-stiffness PET film may be composed of biomass-derived PET and fossil fuel-derived PET. By including biomass-derived PET in the high-stiffness PET film, the amount of fossil fuel-derived PET can be reduced compared to conventional methods, thereby reducing carbon dioxide emissions and environmental impact. Note that biomass-derived PET has biomass-derived ethylene glycol as the diol unit and fossil fuel-derived terephthalic acid as the dicarboxylic acid unit. Fossil fuel-derived PET has fossil fuel-derived ethylene glycol as the diol unit and fossil fuel-derived terephthalic acid as the dicarboxylic acid unit.

[0058] Atmospheric carbon dioxide contains a certain proportion of C14 (105.5 pMC), and it is known that the C14 content in plants that grow by absorbing atmospheric carbon dioxide, such as corn, is also approximately 105.5 pMC. It is also known that fossil fuels contain very little C14. Therefore, the proportion of biomass-derived carbon can be calculated by measuring the proportion of C14 in the total carbon atoms in PET. In this specification, "biomass ratio" refers to the weight ratio of biomass-derived components. Taking PET as an example, PET is a polymer formed by polymerizing ethylene glycol containing two carbon atoms and terephthalic acid containing eight carbon atoms in a 1:1 molar ratio. If only biomass-derived ethylene glycol is used in PET, the weight ratio of biomass-derived components in PET is 31.25%, and the theoretical biomass ratio of PET is 31.25%. Specifically, the mass of PET is 192, of which 60 is derived from biomass-derived ethylene glycol, so 60 ÷ 192 × 100 = 31.25. Furthermore, the weight ratio of biomass-derived components in fossil fuel-derived PET is 0%, and the biomass content of fossil fuel-derived PET is 0%. In the present invention, the biomass content of the high-stiffness PET film is preferably 5.0% or more, and more preferably 10.0% or more. Furthermore, the biomass content of the high-stiffness PET film is preferably 30.0% or less.

[0059] Biomass-derived ethylene glycol is made from ethanol produced from biomass (biomass ethanol). For example, biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene oxide by a conventionally known method to produce ethylene glycol. Examples of raw materials for biomass ethanol include corn, sugarcane, beet, and manioc. Commercially available biomass ethylene glycol may also be used; for example, biomass ethylene glycol commercially available from India Glycoal Limited can be suitably used. Note that India Glycoal's biomass ethylene glycol is made from sugarcane molasses.

[0060] When one of the first stretched plastic film 40 or the second stretched plastic film 50 is a high-stiffness polyester film, the other of the first stretched plastic film 40 or the second stretched plastic film 50 contains polyester or polyamide as a primary component. For example, when the first stretched plastic film 40 is a high-stiffness polyester film, the second stretched plastic film 50 may be a stretched plastic film containing 51% by mass or more of polyester or polyamide as a primary component. When the second stretched plastic film 50 is a high-stiffness polyester film, the first stretched plastic film 40 may be a stretched plastic film containing 51% by mass or more of polyester or polyamide as a primary component. Alternatively, both the first stretched plastic film 40 and the second stretched plastic film 50 may be high-stiffness polyester films.

[0061] Furthermore, when the bag 10 made from the packaging material 30 is subjected to a high-temperature sterilization process such as boiling or retort processing, it is preferable that the stretched plastic film constituting the other of the first stretched plastic film 40 or the second stretched plastic film 50 contains polyester as its main component.

[0062] Stretched plastic films containing polyester as a primary component (hereinafter also referred to as stretched polyester films) contain, for example, 51% by mass or more of polyester. As with high-stiffness polyester films, the polyester is preferably a polyester primarily composed of an aromatic polyester consisting of at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid and at least one aliphatic alcohol selected from ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Examples of polyesters include PET and PBT. In addition, the 51% by mass or more of polyester in a stretched polyester film may be composed of one type of polyester or two or more types of polyester.

[0063] The thickness of the stretched polyester film is preferably 9 μm or more, more preferably 12 μm or more. The thickness of the stretched polyester film is preferably 25 μm or less, more preferably 20 μm or less. By making the thickness of the stretched polyester film 9 μm or more, the stretched polyester film has sufficient strength. By making the thickness of the stretched polyester film 25 μm or less, the stretched polyester film exhibits excellent formability. Therefore, the process of processing the packaging material 30 to manufacture the bag 10 can be carried out efficiently.

[0064] Preferably, the material constituting the stretched polyester film has a thermal conductivity equal to or greater than a predetermined value. For example, the thermal conductivity of the material constituting the stretched polyester film is preferably 0.05 W / m·K or greater, and more preferably 0.1 W / m·K or greater. The thermal conductivity of PET is, for example, 0.14 W / m·K. The thermal conductivity of PBT is higher than that of PET, for example, 0.25 W / m·K. By using a material with a thermal conductivity equal to or greater than a predetermined value, the heat resistance of the packaging material 30 can be improved.

[0065] The melting point of the stretched polyester film is preferably 200° C. or higher, and more preferably 220° C. or higher. By setting the melting point of the stretched polyester film to 220° C. or higher, it is possible to prevent holes from being formed in the stretched polyester film or wrinkles from being formed in the stretched polyester film when the contents contained in the bag 10 produced using the packaging material 30 are heated.

[0066] When the stretched polyester film contains PET, the PET may contain biomass-derived PET, as in the case of the high-stiffness polyester film described above. In this case, the stretched polyester film may be composed solely of biomass-derived PET. Alternatively, the stretched polyester film may be composed of biomass-derived PET and fossil fuel-derived PET. The biomass-derived PET contained in the stretched polyester film and the biomass content of the stretched polyester film are the same as in the case of the high-stiffness polyester film described above, so further explanation is omitted.

[0067] Stretched plastic films containing polyamide as a main component (hereinafter also referred to as stretched polyamide films) contain, for example, 51% by mass or more of polyamide. Examples of polyamides include aliphatic polyamides and aromatic polyamides. Aliphatic polyamides include nylons such as nylon-6, nylon-6,6, and copolymers of nylon 6 and nylon 6,6, and aromatic polyamides include polymetaxylene adipamide (MXD6). By providing the packaging material 30 with a stretched polyamide film, the puncture strength of the packaging material 30 can be increased.

[0068] A stretched polyamide film may be composed of a single layer or multiple layers. When a stretched polyamide film includes multiple layers, it is, for example, a co-extruded film produced by co-extrusion. A co-extruded film includes, for example, a first layer made of a polyester such as PET, a second layer made of a polyamide such as nylon, and a third layer made of a polyester such as PET, laminated in this order. Note that when the mass of the second layer made of a polyamide such as nylon is 51% or more of the mass of the entire co-extruded film, it can be said that the main component of the co-extruded film is polyamide.

[0069] Preferably, the stretched polyester film or stretched polyamide film constituting the other of the first stretched plastic film 40 and the second stretched plastic film 50 is configured to have tearability in the machine direction (MD). In the following description, a stretched polyester film or stretched polyamide film having tearability in the machine direction (MD) is also referred to as a straight-cut film. The use of a straight-cut film can impart tearability in the machine direction (MD) to the packaging material 30. In the bag 10 shown in FIG. 1, the first direction D1 corresponds to the machine direction (MD) of the stretched plastic films 40, 50, etc., and the second direction D2 corresponds to the transverse direction (TD) of the stretched plastic films 40, 50, etc.

[0070] The following describes straight-cut films. The tensile strength of straight-cut films in the machine direction (MD) is greater than that in the transverse direction (TD). The tensile strength of straight-cut films in the machine direction (MD) is preferably 1.05 times or more, more preferably 1.10 times or more, and even more preferably 1.2 times or more, of the tensile strength of straight-cut films in the transverse direction (TD). The tensile strength of straight-cut films in the machine direction (MD) is, for example, 200 MPa or more and 300 MPa or less.

[0071] The straight-cut film may be a straight-cut polyester film containing polyester as a main component, or a straight-cut polyamide film containing polyamide as a main component.

[0072] In this embodiment, examples of combinations of the first stretched plastic film 40 and the second stretched plastic film 50 are as follows. [Table 1]

[0073] (First adhesive layer) The first adhesive layer 45 contains an adhesive for bonding the first stretched plastic film 40 and the second stretched plastic film 50 by dry lamination. The adhesive constituting the first adhesive layer 45 is produced from an adhesive composition prepared by mixing a first composition containing a base agent and a solvent with a second composition containing a curing agent and a solvent. Specifically, the adhesive contains a cured product produced by reaction of the base agent and the solvent in the adhesive composition.

[0074] An example of an 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 include polyether polyurethane and polyester polyurethane. 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.

[0075] As the isocyanate compound, aromatic isocyanate compounds such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), and xylylene diisocyanate (XDI), aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), or adducts or polymers of the above-mentioned various isocyanate compounds can be used.

[0076] The material constituting the first adhesive layer 45 preferably has a higher thermal conductivity than the materials constituting the first stretched plastic film 40, the second stretched plastic film 50, and the sealant layer 70. For example, the thermal conductivity of the material constituting the first adhesive layer 45 is preferably 1.0 W / m·K or higher, more preferably 3.0 W / m·K or higher. The thermal conductivity of polyurethane is in the range of 3.0 W / m·K to 5.0 W / m·K, e.g., 5.0 W / m·K. The high thermal conductivity of the material constituting the first adhesive layer 45 facilitates heat diffusion in the planar direction of the packaging material 30 when the bag 10 made using the packaging material 30 is heated, as the heat generated in the storage section 17 is transferred from the inner surface 30x of the packaging material 30 to the outer surface 30y of the packaging material 30. This improves the heat dissipation properties of the packaging material 30, thereby suppressing temperature increases in the packaging material 30. This also reduces damage to the packaging material 30 caused by heat when the bag 10 is heated. That is, the heat resistance of the packaging material 30 can be improved.

[0077] The thickness of the first adhesive layer 45 is preferably 2 μm or more, and more preferably 3 μm or more. The thickness of the first adhesive layer 45 is preferably 6 μm or less, and more preferably 5 μm or less. By making the thickness of the first adhesive layer 45 3 μm or more, heat diffusion in the surface direction of the packaging material 30 becomes easier to occur.

[0078] (Second adhesive layer) The second adhesive layer 55 contains an adhesive for bonding the second stretched plastic film 50 and the sealant layer 70 by dry lamination. An example of the adhesive for the second adhesive layer 55 is polyurethane, as in the case of the first adhesive layer 45. In addition to the configuration, materials, and properties described below, the second adhesive layer 55 can also be configured, made of the same materials, and have the same properties as the first adhesive layer 45.

[0079] Like the first adhesive layer 45, the material constituting the second adhesive layer 55 preferably has a higher thermal conductivity than the materials constituting the first stretched plastic film 40, the second stretched plastic film 50, and the sealant layer 70. For example, the thermal conductivity of the material constituting the second adhesive layer 55 is preferably 1 W / m·K or more, and more preferably 3 W / m·K or more.

[0080] The thickness of the second adhesive layer 55 is preferably 2 μm or more, and more preferably 3 μm or more. The thickness of the second adhesive layer 55 is preferably 6 μm or less, and more preferably 5 μm or less.

[0081] As described above, the isocyanate compounds that constitute the curing agent of the adhesive include aromatic isocyanate compounds and aliphatic isocyanate compounds. Among these, aromatic isocyanate compounds leach out components that cannot be used in food applications under high-temperature conditions such as heat sterilization. The second adhesive layer 55 contacts the sealant layer 70. Therefore, if the second adhesive layer 55 contains an aromatic isocyanate compound, components leach out from the aromatic isocyanate compound may adhere to the contents contained in the container 17 that contacts the sealant layer 70.

[0082] In consideration of these issues, a cured product produced by the reaction of a polyol as the main agent with an aliphatic isocyanate compound as the curing agent is preferably used as the adhesive that constitutes the second adhesive layer 55. This makes it possible to prevent components that cannot be used for food applications, which originate from the second adhesive layer 55, from adhering to the contents.

[0083] (sealant layer) Next, the sealant layer 70 will be described. The material constituting the sealant layer 70 can be one or more resins selected from polyethylene, such as low-density polyethylene and linear low-density polyethylene, and polypropylene. The sealant layer 70 may be a single layer or a multilayer. The sealant layer 70 is preferably made of an unstretched sealant film. Note that the term "unstretched" encompasses not only a film that is not stretched at all, but also a film that is slightly stretched due to the tension applied during film formation.

[0084] The sealant film constituting the sealant layer 70 is, for example, a plastic film that has been stretched to an extent necessary for transportation but has not been intentionally stretched. Preferred mechanical properties of the sealant film will be further described. The tensile modulus of the sealant film in at least one direction is preferably 1000 MPa or less, for example, the tensile modulus of the sealant film in the machine direction and perpendicular direction is preferably 1000 MPa or less. The tensile elongation of the sealant film in at least one direction is preferably 300% or more, for example, the tensile elongation of the sealant film in the machine direction and the perpendicular direction is preferably 300% or more.

[0085] The tensile modulus and tensile elongation of the sealant film can be measured in accordance with JIS K7127, as in the case of high-stiffness polyester films. A tensile tester STA-1150 manufactured by Orientec Co., Ltd. can be used as the measuring instrument. A rectangular film 15 mm wide and 150 mm long cut from the film can be used as the test piece. The distance between the pair of chucks holding the test piece at the start of measurement is 100 mm, and the tensile speed is 300 mm / min.

[0086] Bags 10 made from packaging material 30 may be subjected to sterilization treatments such as boiling or retort treatment at high temperatures. The sealant layer 70 preferably has heat resistance that can withstand these high-temperature treatments. Retort treatment is a process in which the contents are filled into bag 10, the bag 10 is sealed, and then the bag 10 is heated under pressure using steam or heated hot water. The temperature for retort treatment is, for example, 120°C or higher. Boiling treatment is a process in which the contents are filled into bag 10, the bag 10 is sealed, and then the bag 10 is heated in a water bath under atmospheric pressure. The temperature for boiling treatment is, for example, 90°C or higher and 100°C or lower.

[0087] The melting point of the material that makes up sealant layer 70 is preferably 150°C or higher, and more preferably 160°C or higher. Increasing the melting point of sealant layer 70 makes it possible to perform retort processing of bag 10 at a high temperature, thereby shortening the time required for retort processing. Note that the melting point of the material that makes up sealant layer 70 is lower than the melting point of the resin that makes up stretched plastic films 40, 50.

[0088] From the perspective of retort processing, a material primarily composed of propylene can be used to form the sealant layer 70. Here, a material "primarily composed of" propylene refers to a material with a propylene content of 90% by mass or more. Specific examples of materials primarily composed of propylene include polypropylenes such as propylene-ethylene block copolymers, propylene-ethylene random copolymers, and homopolypropylenes, as well as mixtures of polypropylene and polyethylene. Here, "propylene-ethylene block copolymers" refer to materials having the structural formula shown in formula (I) below. Furthermore, "propylene-ethylene random copolymers" refer to materials having the structural formula shown in formula (II) below. Furthermore, "homopolypropylene" refers to materials having the structural formula shown in formula (III) below.

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] When a mixture of polypropylene and polyethylene is used as the propylene-based material, the material may have an island-in-a-sea structure, where the polyethylene is discontinuously dispersed within a continuous polypropylene region.

[0093] Considering the boiling treatment, examples of the material constituting the sealant layer 70 include polyethylene, polypropylene, and a combination thereof. Examples of polyethylene include medium-density polyethylene, linear low-density polyethylene, and a combination thereof. For example, it is also possible to use the materials listed above as materials constituting the sealant layer 70 from the viewpoint of retort treatment. The material constituting the sealant layer 70 has a melting point of, for example, 100°C or higher, more preferably 105°C or higher, more preferably 110°C or higher, and even more preferably 115°C or higher. When polyethylene is used as the material constituting the sealant layer 70, a melting point of 100°C or higher is achieved, for example, when the density of polyethylene is 0.920 g / cm. 3 This can be achieved when the above conditions are satisfied. Specific examples of sealant layers for constituting the sealant layer 70 having a melting point of 100°C or higher include TUX-HC manufactured by Mitsui Chemicals Tohcello, L6101 manufactured by Toyobo, and LS700C manufactured by Idemitsu Unitech. Specific examples of sealant layers for constituting the sealant layer 70 having a melting point of 105°C or higher include NB-1 manufactured by Tamapoly. Specific examples of sealant layers for constituting the sealant layer 70 having a melting point of 110°C or higher include LS760C manufactured by Idemitsu Unitech and TUX-HZ manufactured by Mitsui Chemicals Tohcello.

[0094] Preferably, the sealant layer 70 is a single-layer film containing a propylene-ethylene block copolymer. For example, the sealant layer including the sealant layer 70 is a single-layer unstretched film whose main component is a propylene-ethylene block copolymer. By using a propylene-ethylene block copolymer, the impact resistance of the sealant layer can be increased, thereby preventing the bag 10 from breaking due to an impact when dropped. Furthermore, the puncture resistance of the packaging material 30 can be increased.

[0095] A propylene-ethylene block copolymer, for example, contains a sea component made of polypropylene and island components made of an ethylene-propylene copolymer rubber component. The sea component can contribute to improving the blocking resistance, heat resistance, rigidity, seal strength, etc. of the propylene-ethylene block copolymer. The island components can also contribute to improving the impact resistance of the propylene-ethylene block copolymer. Therefore, by adjusting the ratio of the sea component to the island component, the mechanical properties of a sealant layer containing a propylene-ethylene block copolymer can be adjusted.

[0096] In the propylene-ethylene block copolymer, the mass ratio of the sea part made of polypropylene is higher than the mass ratio of the island part made of ethylene-propylene copolymer rubber component. For example, in the propylene-ethylene block copolymer, the mass ratio of the sea part made of polypropylene is at least 51 mass% or more, preferably 60 mass% or more, and more preferably 70 mass% or more.

[0097] The single-layer sealant layer may further contain a second thermoplastic resin in addition to the first thermoplastic resin consisting of a propylene-ethylene block copolymer. Examples of the second thermoplastic resin include α-olefin copolymers and polyethylene. An example of an α-olefin copolymer is linear low-density polyethylene. Examples of polyethylene include low-density polyethylene, medium-density polyethylene, and high-density polyethylene. The second thermoplastic resin may contribute to increasing the impact resistance of the sealant layer.

[0098] Low density polyethylene has a density of 0.910 g / cm 3 or more and 0.925g / cm 3 Medium density polyethylene has a density of 0.926 g / cm 3 or more and 0.940 g / cm 3 High density polyethylene is polyethylene with a density of 0.941 g / cm 3 or more and 0.965g / cm 3The following polyethylenes are available: Low-density polyethylene is obtained by polymerizing ethylene at a high pressure, for example, of 1000 atmospheres or more and less than 2000 atmospheres; medium-density polyethylene and high-density polyethylene are obtained by polymerizing ethylene at a medium or low pressure, for example, of 1 atmosphere or more and less than 1000 atmospheres.

[0099] It should be noted that medium-density polyethylene and high-density polyethylene may partially contain a copolymer of ethylene and an α-olefin. Even when ethylene is polymerized under medium or low pressure, medium-density or low-density polyethylene can be produced if it contains a copolymer of ethylene and an α-olefin. Such polyethylene is referred to as the linear low-density polyethylene mentioned above. Linear low-density polyethylene is obtained by copolymerizing an α-olefin with a linear polymer obtained by polymerizing ethylene under medium or low pressure to introduce short-chain branches. Examples of α-olefins include 1-butene (C4), 1-hexene (C6), 4-methylpentene (C6), and 1-octene (C8). The density of linear low-density polyethylene is, for example, 0.915 g / cm. 3 or more and 0.945 g / cm 3 The following is the result.

[0100] The α-olefin copolymer constituting the second thermoplastic resin of the propylene-ethylene block copolymer is not limited to the linear low-density polyethylene described above. The α-olefin copolymer refers to a material having the structural formula shown in formula (IV) below.

[0101] [ka] Both R1 and R2 are H (hydrogen atom) or alkyl groups such as CH3 and C2H5. Furthermore, both j and k are integers of 1 or greater. Furthermore, j is greater than k. That is, in the α-olefin copolymer represented by formula (IV), the structure on the left side including R1 is the base. R1 is, for example, H, and R2 is, for example, C2H5.

[0102] In the sealant layer, the mass ratio of the first thermoplastic resin comprising a propylene-ethylene block copolymer is higher than the mass ratio of the second thermoplastic resin containing at least an α-olefin copolymer or polyethylene. For example, in a single sealant layer, the mass ratio of the first thermoplastic resin comprising a propylene-ethylene block copolymer is at least 51 mass% or more, preferably 60 mass% or more, and more preferably 70 mass% or more.

[0103] As described above, the second thermoplastic resin can contribute to increasing the impact resistance of the sealant layer. Therefore, by adjusting the mass ratio of the second thermoplastic resin containing at least an α-olefin copolymer or polyethylene in the single sealant layer, the mechanical properties of the sealant layer can be adjusted.

[0104] The sealant layer 70 may further contain a thermoplastic elastomer. By using a thermoplastic elastomer, the impact resistance and puncture resistance of the sealant layer 70 can be further improved.

[0105] The thermoplastic elastomer is, for example, a hydrogenated styrene-based thermoplastic elastomer. The hydrogenated styrene-based thermoplastic elastomer has a structure consisting of a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one hydrogenated conjugated diene compound. The thermoplastic elastomer may also be an ethylene-α-olefin elastomer. The ethylene-α-olefin elastomer is a low-crystalline or amorphous copolymer elastomer, and is a random copolymer of 50 to 90% by mass of ethylene as the main component and an α-olefin as a copolymerization monomer.

[0106] The content of the propylene-ethylene block copolymer in the sealant layer 70 is, for example, 80% by mass or more, and preferably 90% by mass or more.

[0107] Propylene-ethylene block copolymers can be produced by polymerizing the raw materials propylene and ethylene using a catalyst, such as a Ziegler-Natta catalyst or a metallocene catalyst.

[0108] The thickness of the sealant layer 70 is preferably 30 μm or more, and more preferably 40 μm or more. The thickness of the sealant layer 70 is preferably 100 μm or less, and more preferably 80 μm or less.

[0109] In the following, preferred mechanical properties of the sealant film when the sealant layer 70 is made of a single layer sealant film containing a propylene-ethylene block copolymer will be described. The tensile elongation of the sealant film in the machine direction (MD) at 25°C is preferably 600% or more and 1300% or less. The product of the tensile elongation (%) of the sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 35,000 or more and 80,000 or less. The tensile elongation of the sealant film in the transverse direction (TD) at 25°C is preferably 700% or more and 1400% or less. The product of the tensile elongation (%) of the sealant film in the transverse direction (TD) and the thickness (μm) of the sealant film is preferably 40,000 or more and 85,000 or less. The tensile modulus of the sealant film in the machine direction (MD) at 25°C is preferably 400 MPa or more and 1100 MPa or less. The product of the tensile modulus of the sealant film in the machine direction (MD) (MPa) and the thickness (μm) of the sealant film is preferably 30,000 or more and 55,000 or less. The tensile modulus of the sealant film in the transverse direction (TD) at 25°C is preferably 250 MPa or more and 900 MPa or less. The product of the tensile modulus of the sealant film in the transverse direction (TD) (MPa) and the thickness (μm) of the sealant film is preferably 20,000 or more and 45,000 or more. 1, the first direction D1 corresponds to the machine direction (MD) of the sealant film, and the second direction D2 corresponds to the perpendicular direction (TD) of the sealant film.

[0110] The tensile modulus and tensile elongation can be measured in accordance with JIS K7127. A tensile tester STA-1150 manufactured by Orientec Co., Ltd. can be used as a measuring device. In the bag 10 shown in FIG. 1 , the direction in which the upper portion 11 and the lower portion 12 extend is the machine direction of the film constituting the bag 10, such as a sealant film, and the direction in which the side portion 13 extends is perpendicular to the film constituting the bag 10, such as a sealant film. Although not shown, the bag 10 may be configured so that the direction in which the upper portion 11 and the lower portion 12 extend is perpendicular to the film and the direction in which the side portion 13 extends is the machine direction of the film.

[0111] There are two main types of single-layer sealant films containing propylene-ethylene block copolymers. The first type is a type that has high tensile elongation and impact resistance, such as unstretched polypropylene film ZK500 manufactured by Toray Advanced Film Co., Ltd. The first type of sealant film preferably also has the property of low hot seal strength. This prevents excessive internal pressure in the storage section 17 when the bag 10 is heated, thereby preventing damage to the packaging material 30. The second type is a type with a high tensile modulus, such as unstretched polypropylene film ZK207 manufactured by Toray Advanced Film Co., Ltd. Use of the second type of sealant film can improve tearability when a consumer tears bag 10 along first direction D1 to open bag 10.

[0112] The product of the tensile elongation (%) of the first type sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 45,000 or more, more preferably 50,000 or more, or may be 55,000 or more, or 60,000 or more. The product of the tensile elongation (%) of the first type sealant film in the transverse direction (TD) and the thickness (μm) of the sealant film is preferably 53,000 or more, more preferably 60,000 or more. When the sealant film has a high tensile elongation, it is possible to prevent the bag 10 from breaking due to an impact when dropped, for example. Furthermore, the product of the tensile modulus (MPa) of the first type sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably not more than 38,000, more preferably not more than 35,000. Furthermore, the product of the tensile modulus (MPa) of the first type sealant film in the transverse direction (TD) and the thickness (μm) of the sealant film is preferably not more than 30,000, more preferably not more than 25,000.

[0113] The product of the tensile modulus (MPa) of the second type sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 35,000 or more, more preferably 38,000 or more, and even more preferably 45,000 or more. The product of the tensile modulus (MPa) of the second type sealant film in the transverse direction (TD) and the thickness (μm) of the sealant film is preferably 25,000 or more, more preferably 30,000 or more, even more preferably 35,000 or more, and may be 38,000 or more. When the sealant film has a high tensile modulus, the tearability when opening the bag 10 can be improved. Furthermore, the product of the tensile elongation (%) of the second type sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably not more than 55,000, more preferably not more than 50,000. Furthermore, the product of the tensile elongation (%) of the second type sealant film in the transverse direction (TD) and the thickness (μm) of the sealant film is preferably not more than 60,000, more preferably not more than 55,000.

[0114] The sealant layer 70 may have easy-peel properties. Easy-peel properties refer to the property that, when a packaging material 30 having a sealant layer 70 is used to form a lid for a container, the lid can be easily peeled from the flange of the container at its underside, i.e., at the sealant layer 70. Easy-peel properties can be achieved, for example, by forming the sealant layer 70 from two or more types of resins, with one resin being incompatible with the other resins. Examples of resins that can achieve easy-peel properties include mixed resins of polyethylene and polypropylene, such as high-density polyethylene.

[0115] 12, the sealant layer 70 may include a first layer 71 located on the second stretched plastic film 50 side, and a second layer 72 located inside the first layer 71 and constituting the inner surface 30x of the packaging material 30. The first layer 71 and second layer 72 of the sealant layer 70 having easy peel properties can be mainly of two types, such as Type A and Type B described below.

[0116] In the A-type sealant layer 70, the first layer 71 is a layer containing polyethylene as a main component, and the second layer 72 is a layer containing a mixed resin of polyethylene and polypropylene. In the second layer 72, the blend ratio of polypropylene is higher than the blend ratio of polyethylene. The mass ratio of polypropylene to polyethylene in the second layer 72 is 6:4 to 8:2.

[0117] When the packaging material 30 having the A-type sealant layer 70 is used in a packaged product for heat sterilization, the density of the polyethylene in the sealant layer 70 is set to 0.940 g / cm 3 It is preferable that the above is set.

[0118] The polypropylene in the second layer 72 of the A-type sealant layer 70 may be, for example, an ethylene-propylene random copolymer.

[0119] In the A-type sealant layer 70, the ratio of the thickness of the first layer 71 to the thickness of the second layer 72 can be set to 5:1 to 10:1.

[0120] In the B-type sealant layer 70, the first layer 71 is a layer containing polypropylene as a main component, and the second layer 72 is a layer containing a mixed resin of polyethylene and polypropylene. In the second layer 72, the blend ratio of polypropylene is higher than the blend ratio of polyethylene. The mass ratio of polypropylene to polyethylene in the second layer 72 is 6:4 to 8:2.

[0121] When the packaging material 30 having the B-type sealant layer 70 is used in a packaged product for heat sterilization, the density of the polyethylene in the sealant layer 70 is set to 0.940 g / cm 3 It is preferable that the above is set.

[0122] The polypropylene in the first layer 71 of the B-type sealant layer 70 may be, for example, an ethylene-propylene block copolymer. The polypropylene in the second layer 72 of the B-type sealant layer 70 may be, for example, an ethylene-propylene random copolymer.

[0123] In the B-type sealant layer 70, the ratio of the thickness of the first layer 71 to the thickness of the second layer 72 can be set to 3:1 to 8:1.

[0124] The sealant layer 70 may be a resin layer provided by an extrusion method or the like on the inner surface side of the second stretched plastic film 50. In this case, the second adhesive layer 55 described above does not need to be present between the second stretched plastic film 50 and the sealant layer 70.

[0125] (Other layers) The packaging material 30 may further include a printed layer 32. In the example shown in Figure 2, the printed layer 32 is located between the first stretched plastic film 40 and the first adhesive layer 45.

[0126] As shown in FIG. 2, the packaging material 30 may further include a printed layer 32 provided on the first stretched plastic film 40. The printed layer 32 is a layer for displaying information about the contents or packaged product, or for adding aesthetic appeal to a packaged product such as a bag 10. The printed layer expresses letters, numbers, symbols, figures, pictures, etc. Gravure printing ink or flexographic printing ink can be used as a material for the printed layer. A specific example of gravure printing ink is Finart, manufactured by DIC Graphics Corporation.

[0127] Fig. 3 is a cross-sectional view showing a modified example of the layer structure of the packaging material 30. As shown in Fig. 3, the packaging material 30 may include a vapor deposition layer 34 located on the surface of the first stretched plastic film 40 facing the inner surface 30x. The packaging material 30 may further include a transparent gas barrier coating film 36 located on the surface of the vapor deposition layer 34.

[0128] Fig. 4 is a cross-sectional view showing a modified example of the layer structure of the packaging material 30. As shown in Fig. 4, the vapor deposition layer 34 may be located on the surface of the second stretched plastic film 50 facing the outer surface 30y. In addition, a gas barrier coating film 36 may be provided on the surface of the vapor deposition layer 34.

[0129] The vapor deposition layer 34 and the gas barrier coating film 36 will be described below.

[0130] The vapor-deposited layer 34 is a layer provided on the packaging material 30 to improve the gas barrier properties of the packaging material 30. Examples of materials that can be used to form the vapor-deposited layer 34 include metals such as aluminum, metal oxides such as aluminum oxide, and inorganic oxides such as silicon oxide.

[0131] The vapor deposition layer 34 functions as a layer with gas barrier properties that prevent the permeation of oxygen gas, water vapor, and the like. Two or more vapor deposition layers 34 may be provided. When two or more vapor deposition layers 34 are provided, the layers may have the same composition or different compositions. Examples of methods for forming the vapor deposition layer 34 include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. Specifically, the vapor deposition layer can be formed on a film-forming roller using a roller-type vapor deposition film-forming device.

[0132] The vapor deposition layer 34 may be a transparent vapor deposition layer formed of a transparent inorganic material such as aluminum oxide (aluminum oxide) or silicon oxide. In particular, when the printing layer 32 is provided on the inner surface 30x side of the vapor deposition layer 34, the vapor deposition layer 34 is configured as a transparent vapor deposition layer. It is preferable to use an amorphous thin film of aluminum oxide as the transparent vapor deposition layer. Specifically, the transparent vapor deposition layer is formed of a material having the formula AlO X (wherein X is a number in the range of 0.5 to 1.5). The transparent vapor deposition layer can be an amorphous thin film of aluminum oxide in which the value of X decreases in the depth direction from the film surface toward the inner surface. The amorphous thin film of aluminum oxide can be an amorphous thin film of aluminum oxide represented by the formula AlO X(wherein X is a number in the range of 0.5 to 1.5), and it is preferable that the value of X increases in the depth direction from the surface of the thin film toward the inner surface. In the above formula, the value of X can basically be 0.5 or more, but if X is less than 1.0, severe coloring occurs and transparency is poor, so it is preferable to use X = 1.0 or more. Furthermore, since X = 1.5 is a state in which Al and oxygen are completely oxidized, the upper limit of X = 1.5 can be used. In addition, if the value of X in the above formula is 0, it is a completely inorganic element (pure substance) and is not transparent.

[0133] The rate of decrease in the value of X can be confirmed by performing elemental analysis of the transparent vapor-deposited layer using a surface analyzer such as an X-ray photoelectron spectroscopy (XPS) or a secondary ion mass spectroscopy (SIMS), using a method of analysis such as ion etching in the depth direction.

[0134] <First Preferred Form of Transparent Vapor Deposition Layer> A first preferred embodiment of the transparent vapor-deposited layer will be described below. The transparent vapor-deposited layer may be a layer made of a mixture of inorganic compounds containing a covalent bond between an aluminum atom and a carbon atom. In this case, the transparent vapor-deposited layer exhibits the presence of a covalent bond between an aluminum atom and a carbon atom in a peak measured by ion etching in the depth direction using an X-ray photoelectron spectrometer (measurement conditions: X-ray source AlKα, X-ray output 120 W), and may also have transparency and gas barrier properties that prevent the permeation of oxygen, water vapor, etc.

[0135] A covalent bond between a metal atom and a carbon atom may be formed at the interface between the transparent vapor deposition layer and the stretched plastic film. For example, if the transparent vapor deposition layer contains aluminum oxide, a covalent bond between an aluminum atom and a carbon atom may be formed at the interface between the stretched plastic film and the transparent vapor deposition layer. The covalent bond can be detected by X-ray photoelectron spectroscopy (hereinafter abbreviated as "XPS measurement").

[0136] Furthermore, in the transparent vapor-deposited layer, the proportion of covalent bonds between aluminum atoms and carbon atoms is preferably within the range of 0.3% to 30% of all bonds including carbon atoms observed when the interface between the transparent vapor-deposited layer and the stretched plastic film is measured by XPS, which strengthens the adhesion between the transparent vapor-deposited layer and the stretched plastic film, and provides a vapor-deposited film with excellent transparency and well-balanced gas barrier properties.

[0137] If the proportion of covalent bonds between aluminum atoms and carbon atoms is less than 0.3%, the improvement in adhesion of the transparent vapor-deposited layer is insufficient, making it difficult to stably maintain the barrier properties.

[0138] Furthermore, it is preferable that the AL (aluminum) / O (oxygen) ratio of the transparent vapor deposition layer, which is primarily composed of aluminum oxide, is 1.0 or less within a range of 3 nm from the interface between the stretched plastic film and the transparent vapor deposition layer toward the surface of the transparent vapor deposition layer on the side opposite the stretched plastic film. If the AL / O ratio exceeds 1.0 in the range from the interface between the transparent vapor deposition layer and the stretched plastic film toward the surface of the transparent vapor deposition layer on the side opposite the stretched plastic film, the adhesion between the stretched plastic film and the transparent vapor deposition layer will be insufficient, and the proportion of aluminum will increase, reducing the transparency of the transparent vapor deposition layer.

[0139] The thickness of the transparent vapor deposition layer is, for example, 20 Å or more and 200 Å or less, preferably 30 Å or more and 150 Å or more. A thickness less than 30 Å may result in insufficient gas barrier properties. On the other hand, a thickness greater than 150 Å may result in the packaging material 30 being unable to maintain its gas barrier properties. While the reason for this is unclear, a thickness greater than 150 Å is thought to reduce the flexibility of the packaging material 30, resulting in cracks or pinholes forming in the transparent vapor deposition layer when the packaging material 30 is used in a bag 10, resulting in reduced gas barrier properties. The thickness of the transparent vapor deposition layer is preferably 40 Å or more and 130 Å or less, more preferably 50 Å or more and 120 Å or less. The thickness of the transparent vapor deposition layer can be measured, for example, by the fundamental parameter method using an X-ray fluorescence analyzer (product name: RIX2000, manufactured by Rigaku Corporation). The thickness of the transparent vapor deposition layer can be changed by, for example, changing the deposition rate of the transparent vapor deposition layer or the vapor deposition rate.

[0140] The surface of the stretched plastic film may be subjected to a pretreatment such as corona discharge treatment, flame treatment, or plasma treatment. When the pretreatment is plasma treatment, plasma is supplied to the surface of the stretched plastic film using a pretreatment device under a reduced pressure environment of 0.1 Pa to 100 Pa. Plasma can be generated by using an inert gas such as argon alone or a mixture of oxygen, nitrogen, carbon dioxide, or one or more of these gases as a plasma raw material gas and exciting the plasma raw material gas with a potential difference such as a high-frequency voltage.

[0141] Pretreatment allows plasma to be confined near the surface of the stretched plastic film. This changes the surface shape, chemical bonding state, and functional groups of the stretched plastic film, thereby changing the chemical properties of the surface of the stretched plastic film. This makes it possible to improve the adhesion between the stretched plastic film and the transparent vapor deposition layer.

[0142] <Second Preferred Form of Transparent Vapor Deposition Layer> Next, a second preferred embodiment of the transparent vapor-deposited layer will be described. In the present application, the transparent vapor-deposited layer may satisfy both the first preferred embodiment described above and the second preferred embodiment described below, or may satisfy only one of the embodiments. In addition, it is possible that the transparent vapor-deposited layer of the present application does not satisfy either the first preferred embodiment described above or the second preferred embodiment described below.

[0143] The transparent vapor-deposited layer may have a transition region that determines the adhesive strength between the substrate, such as a stretched plastic film, and the transparent vapor-deposited layer, such as an aluminum oxide vapor-deposited film. When the transparent vapor-deposited layer is an aluminum oxide vapor-deposited film, the transition region contains a bonding structure (Al2O4H) that transforms into aluminum hydroxide, as detected by etching the aluminum oxide vapor-deposited film using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The transformation rate of the transition region, defined as the ratio of the transformed transition region determined using TOF-SIMS to the aluminum oxide vapor-deposited film determined by etching using TOF-SIMS, is preferably 45% or less. This embodiment is based on the finding that specifying the transformation rate of the transition region allows for the identification of a packaging material 30 with barrier properties and improved adhesive strength between a stretched plastic film and an aluminum oxide vapor-deposited film.

[0144] The transformation rate in the transition region will be explained in detail. First, the outermost surface of the aluminum oxide vapor-deposited film is etched with Cs using a time-of-flight secondary ion mass spectrometer, and the elemental bonding at the interface between the aluminum oxide vapor-deposited film and the stretched plastic film and the elemental bonding in the vapor-deposited film are measured. Next, actual measurement graphs of the measured elements and elemental bonding are obtained, as shown in Figure 13.

[0145] To minimize the transition region of the aluminum hydroxide in the aluminum oxide vapor-deposited film at the interface between the stretched plastic film and the vapor-deposited film, we focused on AL2O4H. 1) The position where the intensity H0 of the graph for element C6 is half (the position where the intensity becomes H1 in Figure 13) is identified as the interface between the stretched plastic film and the aluminum oxide vapor-deposited film (the position where the horizontal axis (cycle) is T1 in Figure 13). The region from the interface to the surface of the aluminum oxide vapor-deposited film (the position where the horizontal axis (cycle) is T0 in Figure 13) is also identified as the aluminum oxide vapor-deposited film. 2) Next, we found the peak in the graph representing the elemental bond AL2O4H (the position where the horizontal axis (cycle) is T2 in Figure 13), and identified the region from that peak to the interface as the transition region. 3) Next, we calculated the conversion rate to aluminum hydroxide in the transition region by multiplying (the transition region from the peak of the elemental bond AL2O4H to the interface / aluminum oxide vapor-deposited film) by 100%. In the example shown in FIG. 13, the transformation rate is (W2 / W1)×100(%).

[0146] In forming an aluminum oxide vapor-deposited film, it is preferable to perform plasma pretreatment on the surface of the stretched plastic film before the aluminum oxide vapor deposition step in order to achieve a desirable conversion rate in the transition region of the aluminum oxide vapor-deposited film. In the plasma pretreatment, the mixture ratio of oxygen gas to argon or helium supplied as plasma gas is 5:1, preferably 2:1. A mixture ratio of 5:1 increases the energy required to form the vapor-deposited aluminum film on the surface of the stretched plastic film, and a mixture ratio of 2:1 further increases the formation of aluminum hydroxide near the interface with the substrate, i.e., the conversion rate in the transition region decreases.

[0147] As a vapor deposition method for forming the vapor-deposited film, various vapor deposition methods can be applied from among physical vapor deposition and chemical vapor deposition. As a physical vapor deposition method, a method can be selected from the group consisting of vapor deposition, sputtering, ion plating, ion beam assisted deposition, and cluster ion beam deposition. As a chemical vapor deposition method, a method can be selected from the group consisting of plasma CVD, plasma polymerization, thermal CVD, and catalytic reaction CVD. In this embodiment, a physical vapor deposition method is preferred.

[0148] The thickness of the aluminum oxide vapor-deposited film formed as described above is preferably 3 nm or more and 50 nm or less, and more preferably 8 nm or more and 30 nm or less. Within this range, the barrier properties are easily maintained.

[0149] [Gas barrier coating film] The gas barrier coating film 36 is a compound represented by the general formula R 1 n M(OR 2 ) m (wherein, 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 valence of M. The gas barrier coating film 36 is obtained from a transparent gas barrier composition containing at least one alkoxide represented by the formula (I) and the above-mentioned polyvinyl alcohol resin and / or ethylene-vinyl alcohol copolymer, and further polycondensed by a sol-gel method in the presence of a sol-gel catalyst, acid, water, and an organic solvent. It is preferable that the gas barrier coating film 36 is transparent.

[0150] The general formula R 1 n M(OR 2 ) mAs the alkoxide represented by the formula (I), at least one of a partial hydrolyzate of an alkoxide and a condensate of the hydrolysis of an alkoxide can be used. In addition, the partial hydrolyzate of the alkoxide does not necessarily have to have all of the alkoxy groups hydrolyzed, and may be one in which one or more alkoxy groups are hydrolyzed, or a mixture thereof. As the condensate of the hydrolysis of an alkoxide, a dimer or higher of the partially hydrolyzed alkoxide, specifically a dimer to hexamer, is used.

[0151] The general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula (I), silicon, zirconium, titanium, aluminum, and the like can be used as the metal atom represented by M. Preferred metals include silicon and titanium. In the present embodiment, the alkoxide can be used alone or as a mixture of two or more alkoxides of different metal atoms in the same solution.

[0152] In addition, the above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula 1 Specific examples of the organic group represented by the general formula R include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, n-octyl, and the like. 1 n M(OR 2 ) m In the alkoxide represented by the formula 2 Specific examples of the organic group represented by the formula (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. These alkyl groups may be the same or different in the same molecule.

[0153] When preparing the transparent gas barrier composition, for example, a silane coupling agent may be added. As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used. In particular, an organoalkoxysilane having an epoxy group is preferably used, and specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane can be used. The above-mentioned silane coupling agents may be used alone or in combination of two or more.

[0154] The oxygen permeability and water vapor permeability of the packaging material 30 having the vapor deposition layer 34 are preferably 2 or less (cc / m 2 ·day · atm) and less than 2 (g / m 2 ·day). Oxygen permeability is measured in accordance with JIS K7126 (isobaric method) using an oxygen barrier measuring device, OXTRAN, manufactured by Mocon, USA, at 23°C and 90% RH. Water vapor permeability is measured in accordance with JIS K7129 (Method B) using a water vapor barrier measuring device, PERMATRAN, manufactured by Mocon, USA, at 40°C and 90% RH.

[0155] Layer structure of the bottom film Next, the layer structure of the lower film 16 will be described.

[0156] The layer structure of the lower film 16 is arbitrary as long as it has an inner surface that can be bonded to the inner surfaces of the front film 14 and the back film 15. For example, the above-mentioned packaging material 30 may be used as the lower film 16, similar to the front film 14 and the back film 15. Alternatively, a film whose inner surface is formed by a sealant layer and has a different structure from the packaging material 30 may be used as the lower film 16.

[0157] Packaging material manufacturing method Next, an example of a method for producing the packaging material 30 will be described.

[0158] First, prepare the above-mentioned first stretched plastic film 40 and second stretched plastic film 50. The first stretched plastic film 40 or the second stretched plastic film 50 is provided with a printed layer 32, a vapor deposition layer 34, a gas barrier coating film 36, etc., as needed.

[0159] Next, the first stretched plastic film 40 and the second stretched plastic film 50 are laminated together by dry lamination via the first adhesive layer 45. After that, the laminate including the first stretched plastic film 40 and the second stretched plastic film 50 is laminated together with a sealant film for constituting the sealant layer 70 via the second adhesive layer 55 by dry lamination. In this way, a packaging material 30 including the first stretched plastic film 40, the second stretched plastic film 50, and the sealant layer 70 can be obtained.

[0160] Alternatively, the packaging material 30 may be produced by first laminating the second stretched plastic film 50 and the sealant film via the second adhesive layer 55 using a dry lamination method, and then laminating the first stretched plastic film 40 and a laminate including the second stretched plastic film 50 and the sealant layer via the first adhesive layer 45 using a dry lamination method.

[0161] In the dry lamination method, an adhesive composition is first applied to one of the two films to be laminated. The applied adhesive composition is then dried to volatilize the solvent. The two films are then laminated together via the dried adhesive composition. The two laminated films are then rolled up and aged, for example, at 20°C or higher for 24 hours or more.

[0162] Bag manufacturing method Next, a method for manufacturing bag 10 using the above-mentioned packaging material 30 will be described. First, surface film 14 and back film 15 made of packaging material 30 are prepared. Furthermore, folded-over bottom film 16 is inserted between surface film 14 and back film 15. Next, the inner surfaces of each film are heat-sealed to form seals such as bottom seal 12a and side seal 13a. Furthermore, the films joined together by heat sealing are cut into an appropriate shape to obtain bag 10 shown in FIG. 1.

[0163] Next, the contents 18 are filled into the bag 10 through the opening 11b of the top 11. Specifically, as shown in FIG. 14, the pair of side seal portions 13a of the bag 10, which are closest to the top 11, are gripped by a pair of zipper portions 105. Furthermore, as shown by arrow P in FIG. 14, the zipper portions 105 are moved in a direction that narrows the gap between the pair of zipper portions 105 in the width direction of the bag 10. This causes the front film 14 and the back film 15 to deform so as to form the opening 11b in the top 11. At this time, as shown in FIG. 14, suction portions 106 may be attached to the outer surfaces of the front film 14 and the back film 15, and the suction portions 106 may be moved in the direction of arrow Q. This makes it easier to form the opening 11b. Next, the contents 18 are filled into the bag 10 through the opening 11b. The top 11 is then heat-sealed to form the top seal portion 11a. In this manner, a bag 10 containing and sealed with the contents 18 can be obtained.

[0164] Contents 18 are, for example, cooked foods containing water, such as curry, stew, soup, etc. Contents 18 may also contain ingredients with a high oil content, such as meat, fish, and seasonings for those. In addition to food, items that can be heated in a hot water bath or the like can also be placed in bag 10 as contents. Contents that do not require heating may also be placed in bag 10.

[0165] In the present embodiment, a high-stiffness polyester film is used as the first stretched plastic film 40 or the second stretched plastic film 50 of the packaging material 30 constituting the bag 10. This allows the packaging material 30 and the bag 10 to have rigidity and puncture resistance. This makes it possible to prevent the bag 10 from being torn when a sharp object with a pointed tip comes into contact with the bag 10, for example. The puncture strength of the packaging material 30 is preferably 14 N or more, more preferably 15 N or more, more preferably 16 N or more, more preferably 17 N or more, and even more preferably 18 N or more. A method for measuring the puncture strength will be described in the examples below.

[0166] Furthermore, in this embodiment, since the packaging material 30 constituting the front and back films 14 and 15 has rigidity, it becomes easier to form the opening 11b in the upper portion 11 when the zipper portion 105 is moved as shown in FIG. 14 . For example, the front and back films 14 and 15 are each easily deformed to have a curved shape that is convex on the outer surface side. This makes it easier to ensure the opening width K of the opening 11b. Furthermore, in this embodiment, since the packaging material 30 constituting the front and back films 14 and 15 has rigidity, wrinkles are less likely to occur in the front and back films 14 and 15. This makes it easier for the suction portion 106 to suction to the outer surfaces of the front and back films 14 and 15. This can also contribute to ensuring the opening width K of the opening 11b.

[0167] How to open the bag Next, a method for opening the bag 10 will be described. Here, a case where a consumer opens the bag 10 by tearing the bag 10 along the first direction D1 will be described. In this embodiment, as described above, a straight-cut film is used as the first stretched plastic film 40 or the second stretched plastic film 50 of the packaging material 30. This prevents the tearing direction from deviating from the first direction D1 when the consumer tears the bag 10 to open it. This allows the consumer to easily tear the bag 10. Note that, in order to improve the tearability of the bag 10, it is preferable to use the second type of sealant film described above, which has a high tensile modulus.

[0168] It should be noted that various modifications can be made to the above-described embodiment. Below, modifications will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the above-described embodiment, and duplicated explanations will be omitted. Furthermore, if it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified embodiment, the explanations thereof may be omitted.

[0169] (Variations of the bag) Figure 15 is a diagram showing another example of bag 10 provided with packaging material 30. Bag 10 shown in Figure 15 differs only in that it further includes a steam release mechanism 20, and other configurations are substantially the same as bag 10 shown in Figure 1. In bag 10 shown in Figure 15, the same parts as bag 10 shown in Figure 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0170] 15, bag 10 is provided with a steam release mechanism 20 for releasing steam generated when the contents stored in storage section 17 are heated to the outside. Steam release mechanism 20 is configured to communicate between the inside and outside of bag 10 to release steam when the steam pressure reaches or exceeds a predetermined value, and to prevent steam from escaping from places other than steam release mechanism 20.

[0171] When bag 10 equipped with steam release mechanism 20 is heated in a microwave oven or the like, the pressure inside bag 10 may not rise to a level that allows steam to escape to the outside through steam release mechanism 20. In other words, depending on how bag 10 is used, there may be a low probability that steam release mechanism 20 will perform its function of releasing steam to the outside. Even in this case, providing bag 10 with steam release mechanism 20 can further reduce the probability that steam will escape from a location other than steam release mechanism 20 or that bag 10 will burst.

[0172] In the example shown in FIG. 15 , the steam release mechanism 20 has a steam release seal portion 20a that protrudes from the side seal portion 13a toward the inside of the bag 10, and a non-sealed portion 20b that is isolated from the storage portion 17 by the steam release seal portion 20a. The non-sealed portion 20b is in communication with the outside of the bag 10. When the pressure in the storage portion 17 increases due to heating in a microwave oven or the like, the steam release seal portion 20a peels off. Steam in the storage portion 17 can escape to the outside of the bag 10 through the peeled portion of the steam release seal portion 20a and the non-sealed portion 20b. At this time, the heat resistance of the packaging material 30 makes it possible to prevent holes from being formed in the packaging material 30 or the formation of wrinkles in the packaging material 30 during heating.

[0173] The configuration of the steam release mechanism 20 is not limited to the configuration shown in Fig. 15. The configuration of the steam release mechanism 20 is arbitrary as long as it can communicate between the storage section 17 and the outside of the bag 10 when the steam pressure reaches or exceeds a predetermined value.

[0174] 16, the surface film 14 may include a joint portion 14a in which the inner surfaces of the surface films 14 are partially overlapped. The joint portion 14a may be formed, for example, by folding back a single surface film 14 at a fold-back portion 14f to form a pleat. Alternatively, the joint portion 14a may be formed by overlapping portions of two surface films 14.

[0175] The joint portion 14a has a joint seal portion 14b formed therein, which extends from one side seal portion 13a to the other side seal portion 13a. In this case, the steam release mechanism 20 has, for example, a steam release seal portion 20a protruding from the joint seal portion 14b toward the storage portion 17, a non-sealed portion 20b surrounded by the steam release seal portion 20a and the joint seal portion 14b, and a through-hole 20c formed in the surface film 14 in the non-sealed portion 20b.

[0176] In this modification, when the pressure in storage section 17 increases, steam release sealed section 20a peels off, connecting storage section 17 and non-sealed section 20b. Steam that flows from storage section 17 to non-sealed section 20b through the peeled portion of steam release sealed section 20a escapes to the outside of bag 10 through through-hole 20c.

[0177] Note that bag 10 shown in FIG. 16 is placed in a microwave oven so that back surface film 15 contacts the turntable or underside (flat table) of the microwave oven over a wide area. Therefore, the contents are more easily heated uniformly than in a free-standing bag 10 such as that shown in FIG. 15. Furthermore, because the area of ​​bag 10 in contact with the microwave oven is large, the liquid level of the contents is less likely to change even if bag 10 is softened by heating. Therefore, during the heating process using a microwave oven, it is less likely that the contents will adhere to the inner surface of front film 14 or back film 15 above the liquid level of the contents. This prevents the contents adhering to the inner surface of front film 14 or back film 15 from being excessively heated, resulting in the formation of holes in front film 14 or back film 15.

[0178] 17A and 17B are a longitudinal cross-sectional view and a plan view showing a lidded container 110, which is an example of an application of the packaging material 30. The lidded container 110 includes a container body 112 fabricated by sheet molding such as drawing or injection molding, and a lid member 114 joined to the container body 112. The container body 112 has a bottom surface 112a, a side surface 112b, and a flange portion 113 extending horizontally outward from the upper end of the side surface 112b. The lid member 114 is joined to the upper surface of the flange portion 113 of the container body 112 via a seal portion 116. The lid member 114 may include the above-described packaging material 30 having a high-stiffness polyester film. By using the above-described packaging material 30 to form the lid member 114, it is possible to impart excellent puncture strength to the lid member 114. This makes it possible to prevent the lid member 114 from being torn when it comes into contact with a sharp object. Furthermore, if the lidded container 110 is dropped, it is possible to prevent the lidded container 110 from being damaged and the contents from leaking out.

[0179] The sealant layer 70 of the packaging material 30 constituting the lid member 114 may have easy-peel properties. That is, the sealant layer 70 of the packaging material 30 constituting the lid member 114 may have a first layer 71 containing polyethylene or polypropylene as a main component, and a second layer 72 containing a mixed resin of polyethylene and polypropylene and constituting the inner surface 30x.

[0180] In this application, products for packaging items, such as the bag 10 and the lidded container 110, are also referred to as packaging products.

[0181] (Other variations of the bag) In the above-described embodiment, an example has been shown in which bag 10 is a gusseted bag, but there are no particular limitations on the specific configuration of bag 10. For example, bag 10 may be a so-called four-sided sealed bag formed by joining the inner surfaces of front film 14 and back film 15 made of packaging material 30 at upper portion 11, lower portion 12, and side portion 13.

[0182] Second embodiment Next, a second embodiment of the present invention will be described. Similar to the first embodiment, the second embodiment also relates to a packaging material and a packaged product including the packaging material.

[0183] First, the problem to be solved by the second embodiment will be described.

[0184] A variety of packaging materials have been developed and proposed for filling and packaging various items such as food and beverages, pharmaceuticals, chemicals, cosmetics, and others. These packaging materials are required to have various physical properties, depending on the purpose of the packaging, the contents to be filled, the storage and distribution of the packaged product, and other factors. For example, one of these properties is gas barrier properties, which prevent the permeation of oxygen and water vapor.

[0185] A variety of gas barrier materials have been developed and proposed to prevent the permeation of oxygen, water vapor, etc. For example, aluminum foil, nylon film or polyethylene terephthalate film coated with a polyvinylidene chloride resin, polyvinyl alcohol film, saponified ethylene-vinyl acetate copolymer film, polyacrylonitrile resin film, and the like have been developed and proposed.

[0186] Furthermore, in recent years, transparent barrier films have been proposed that have a configuration in which a vapor-deposited layer of an inorganic oxide such as silicon oxide or aluminum oxide is provided on a plastic substrate, or a barrier film that has a vapor-deposited layer of a metal such as aluminum, etc. For example, JP-A-2007-303000 proposes producing a barrier film by forming a vapor-deposited layer of an inorganic oxide on a nylon film.

[0187] Packaging materials are required to have strength such as puncture resistance, which is a property that prevents the packaging bag from being torn even when a sharp-edged member comes into contact with the bag.

[0188] The present embodiment aims to provide a packaging material that can effectively solve such problems.

[0189] Next, the means for solving the problems will be described.

[0190] This embodiment is a packaging material comprising a barrier laminate film, a sealant layer located inside the barrier laminate film, and a stretched plastic film located between the barrier laminate film and the sealant layer or located outside the barrier laminate film, wherein the barrier laminate film comprises a substrate and a vapor-deposited layer containing a metal or an inorganic compound and provided on the substrate, the substrate containing polyester as a main component, and the value obtained by dividing the tensile strength by the tensile elongation of the substrate in at least one direction is 2.0 [MPa / %] or more.

[0191] In the packaging material according to this embodiment, the sealant layer may contain 90% by mass or more of polypropylene.

[0192] In the packaging material according to the present invention, the sealant layer may contain linear low-density polyethylene having a melting point of 100°C or higher.

[0193] In the packaging material according to this embodiment, the sealant layer may have a first layer containing polypropylene and high-density polyethylene, and a second layer containing polypropylene or high-density polyethylene and located closer to the barrier laminate film than the first layer.

[0194] In the packaging material according to this embodiment, the stretched plastic film may be a polyester film or a polyamide film located between the barrier laminate film and the sealant layer.

[0195] In the packaging material according to this embodiment, the stretched plastic film may be a polyester film located outside the barrier laminate film.

[0196] In the packaging material according to the present embodiment, the substrate of the barrier laminate film may have a puncture strength of 9.5 N or more.

[0197] In the packaging material according to this embodiment, the substrate of the barrier laminate film may have a loop stiffness of 0.0017 N or more in the machine direction and the perpendicular direction, and may contain polyester as a main component.

[0198] In the packaging material according to the present embodiment, the base material of the barrier laminate film may contain polybutylene terephthalate as a main component.

[0199] In the packaging material according to the present embodiment, the barrier laminate film may further include a gas barrier coating film provided on the vapor deposition layer.

[0200] In the packaging material according to the present embodiment, the vapor-deposited layer of the barrier laminate film may be a transparent vapor-deposited layer containing an inorganic compound.

[0201] In the packaging material according to the present embodiment, the vapor deposition layer of the barrier laminate film is a transparent vapor deposition layer containing aluminum oxide, and the transparent vapor deposition layer includes a transition region, which is a region between the position of a peak of elemental bond Al2O4H detected by etching the barrier laminate film from the transparent vapor deposition layer side using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and the interface between the transparent vapor deposition layer and the substrate, and the ratio of the thickness of the transition region to the thickness of the transparent vapor deposition layer may be 5% or more and 60% or less.

[0202] This embodiment is a packaged product made from the packaging material described above.

[0203] According to this embodiment, a packaging material having gas barrier properties and strength can be provided.

[0204] The second embodiment will be described in detail below. The packaging material 210 in the second embodiment is characterized by having a high-stiffness polyester film provided with a vapor deposition layer. In the following description, parts that can be configured in the same way as in the first embodiment described above will be given the same names, and duplicated descriptions may be omitted. Furthermore, if it is clear that the effects obtained in the first embodiment described above can also be obtained in the second embodiment, the description may be omitted.

[0205] <Packaging materials> The laminate constituting the packaging material according to this embodiment includes a barrier laminate film and a sealant layer located inside the barrier laminate film. The inside refers to the side of the packaged product formed from the packaging material that contains the contents. The outside refers to the side that faces away from the contents.

[0206] 18 is a cross-sectional view showing an example of a packaging material 210 according to an embodiment of the present invention. The packaging material 210 includes, from outside to inside, a barrier laminate film 205, a printed layer 218, a first adhesive layer 213, a stretched plastic film 214, a second adhesive layer 215, and a sealant layer 212. The barrier laminate film 205 includes at least a substrate 201 and a vapor deposition layer 202 provided on the inner surface of the substrate 201. The barrier laminate film 205 may further include a gas barrier coating film 203 located on the vapor deposition layer 202. The substrate 201 forms an outer surface 210y of the packaging material 210, and the sealant layer 212 forms an inner surface 210x of the packaging material 210.

[0207] In this embodiment, the outer surface refers to the outermost surface of the packaging material 210, and the inner surface refers to the innermost surface of the packaging material 210. Furthermore, in this embodiment, the term "order" in descriptions such as "provided in this order" and "layered in order" refers to the order from the outside to the inside, unless otherwise specified.

[0208] 19 is a cross-sectional view showing an example of a packaging material according to the present embodiment. The packaging material 210 includes, from outside to inside, a stretched plastic film 214, a printed layer 218, a first adhesive layer 213, a barrier laminate film 205, a second adhesive layer 215, and a sealant layer 212. The barrier laminate film 205 includes at least a substrate 201 and a vapor deposition layer 202 provided on the outer surface of the substrate 201. The barrier laminate film 205 may further include a gas barrier coating film 203 located on the vapor deposition layer 202. The stretched plastic film 214 forms an outer surface 210y of the packaging material 210, and the sealant layer 212 forms an inner surface 210x of the packaging material 210.

[0209] The following describes the films and layers that make up the packaging material 210. First, the barrier laminate film 205 will be described.

[0210] [Base material] The substrate 201 used in the barrier laminate film 205 is a polyester film containing polyester as a main component. The substrate 201 contains, for example, 51% by mass or more of polyester. The polyester is preferably a polyester primarily composed of an aromatic polyester composed of at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid and at least one aliphatic alcohol selected from ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Examples of polyesters include polyethylene terephthalate (hereinafter also referred to as PET) and polybutylene terephthalate (hereinafter also referred to as PBT).

[0211] To prevent a packaging container made of a packaging material containing the barrier laminate film 205 from being torn when it comes into contact with a sharp object, it is preferable that the substrate 201 of the barrier laminate film 205 have resistance to punctures and other punctures. Therefore, in this embodiment, it is proposed to use either a high-stiffness PET film or a PBT film as the substrate 201. This, for example, can increase the puncture strength of the substrate 201. For example, the puncture strength of the substrate 201 can be increased to 9.5 N or more, more preferably 10 N or more. Furthermore, the ratio of the tensile strength to the tensile elongation of the substrate 201 can be increased. For example, the value obtained by dividing the tensile strength of the substrate by the tensile elongation in at least one direction is 2.0 [MPa / %] or more. This allows the packaging material containing the barrier laminate film 205 to have sufficient rigidity to prevent the packaging container from being torn when it comes into contact with a sharp object.

[0212] The high-stiffness PET film and PBT film will be described in detail below. First, the high-stiffness PET film will be described.

[0213] The high-stiffness PET film is a stretched plastic film that, like the high-stiffness polyester film described above, has a loop stiffness of 0.0017 N or more in the machine direction (MD) and transverse direction (TD) and contains 51 mass % or more of PET. The thickness of the high-stiffness PET film is preferably 5 μm or more, more preferably 7 μm or more. The thickness of the high-stiffness PET film is preferably 25 μm or less, more preferably 20 μm or less. The method for measuring loop stiffness is the same as in the first embodiment described above.

[0214] The preferred mechanical properties of the high stiffness PET film will be further explained. The puncture strength of the high-stiffness PET film is preferably 9.5 N or more, and more preferably 10.0 N or more.

[0215] The tensile strength, tensile elongation, the value obtained by dividing the tensile strength by the tensile elongation, the heat shrinkage rate, and the tensile modulus of the high stiffness PET film in the machine direction are the same as those of the high stiffness polyester film of the first embodiment described above, and therefore, description thereof will be omitted.

[0216] The manufacturing process for high-stiffness PET films is similar to that for high-stiffness polyester films. For example, a PET film obtained by melting and molding polyethylene terephthalate is first stretched 3 to 4.5 times in both the machine direction and the perpendicular direction at 90 to 145°C in a first stretching step. This is followed by a second stretching step in which the plastic film is stretched 1.1 to 3.0 times in both the machine direction and the perpendicular direction at 100 to 145°C in a second stretching step. This is followed by heat setting at 190 to 220°C. This is followed by a relaxation treatment (treatment to reduce the film width) of approximately 0.2 to 2.5% in both the machine direction and the perpendicular direction at 100 to 190°C. By adjusting the stretch ratio, stretching temperature, heat setting temperature, and relaxation treatment rate in these steps, a high-stiffness PET film with the above-mentioned mechanical properties can be obtained.

[0217] The PET constituting the high-stiffness PET film may contain biomass-derived PET, as in the case of the first embodiment described above. In this case, the high-stiffness PET film may be composed only of biomass-derived PET. Alternatively, the high-stiffness PET film may be composed of biomass-derived PET and fossil fuel-derived PET. The biomass-derived PET contained in the high-stiffness PET film and the biomass content of the high-stiffness PET film are the same as in the case of the high-stiffness polyester film of the first embodiment described above, so explanations will be omitted.

[0218] Next, the PBT film will be described. The PBT film is a stretched plastic film containing 51% by mass or more of PBT. The advantages of the base material 201 containing PBT will be described below.

[0219] PBT has excellent heat resistance. This makes it possible to prevent deformation of the substrate 201 or a decrease in the strength of the substrate 201 when a packaging bag containing contents such as food is subjected to a boiling treatment or a retort treatment. Retort treatment is a process in which the contents are filled into a packaging bag, the packaging bag is sealed, and then the packaging bag is heated under pressure using steam or heated hot water. The temperature for retort treatment is, for example, 120°C or higher. Boiling treatment is a process in which the contents are filled into a packaged product, the packaged product is sealed, and then the packaged product is heated in a water bath under atmospheric pressure. The temperature for boiling treatment is, for example, 90°C or higher and 100°C or lower.

[0220] Furthermore, PBT has high strength. Therefore, the packaging bag can be made puncture-resistant, similar to when the packaging material 210 constituting the packaging bag contains nylon. The puncture strength of the PBT film is preferably 9.5 N or more, and more preferably 10.0 N or more.

[0221] The tensile strength of the PBT film in the machine direction is preferably 150 MPa or more, more preferably 180 MPa or more, and the tensile strength of the PBT film in the perpendicular direction is preferably 250 MPa or more, more preferably 280 MPa or more. The tensile elongation of the PBT film in the machine direction is preferably 220% or less, more preferably 200% or less, and the tensile elongation of the PBT film in the perpendicular direction is preferably 120% or less, more preferably 110% or less. Preferably, the value of the tensile strength of the PBT film divided by the tensile elongation in at least one direction is 2.0 [MPa / %] or more. For example, the value of the tensile strength of the PBT film divided by the tensile elongation in the transverse direction (TD) is preferably 2.0 [MPa / %] or more, more preferably 2.2 [MPa / %] or more, and even more preferably 2.5 [MPa / %] or more.

[0222] Furthermore, PBT has the property of being less resistant to moisture absorption than nylon, so even if the base material 201 containing PBT is placed on the outer surface of the packaging material 210, it is possible to prevent the base material 201 from absorbing moisture, which would otherwise reduce the laminate strength of the packaging material 210.

[0223] The structure of the PBT-containing substrate 201 will be described in detail below. In this embodiment, the PBT-containing substrate 201 may have either the first structure or the second structure described below.

[0224] [First configuration of substrate containing PBT] The PBT content in the base material 201 according to the first configuration is preferably 51% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, particularly preferably 75% by mass or more, and most preferably 80% by mass or more. By making the PBT content 51% by mass or more, the base material 201 can have excellent impact strength and pinhole resistance.

[0225] The PBT used as the main constituent preferably contains 90 mol % or more, more preferably 95 mol % or more, even more preferably 98 mol % or more, and most preferably 100 mol % of terephthalic acid as a dicarboxylic acid component, and preferably contains 90 mol % or more, more preferably 95 mol % or more, even more preferably 97 mol % or more of 1,4-butanediol as a glycol component, and most preferably contains no by-products other than those formed by ether bonds of 1,4-butanediol during polymerization.

[0226] The substrate 201 may contain a polyester resin other than PBT, which makes it possible to adjust the film formability and mechanical properties of the substrate 201 when the film-like substrate 201 is biaxially stretched, for example. Examples of polyester resins other than PBT include polyester resins such as PET, polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polypropylene terephthalate (PPT), as well as PBT resins copolymerized with dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, and sebacic acid, and PBT resins copolymerized with diol components such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, cyclohexanediol, polyethylene glycol, polytetramethylene glycol, and polycarbonate diol.

[0227] The amount of the polyester resin other than PBT added is preferably 49% by mass or less, more preferably 40% by mass or less. If the amount of the polyester resin other than PBT added exceeds 49% by mass, the mechanical properties of PBT may be impaired, and impact strength, pinhole resistance, and draw formability may become insufficient.

[0228] The substrate 201 may contain, as an additive, a polyester-based or polyamide-based elastomer obtained by copolymerizing at least one of a flexible polyether component, a polycarbonate component, and a polyester component. This can improve pinhole resistance when bent. The amount of additive added is, for example, 20% by mass. If the amount of additive added exceeds 20% by mass, the effect of the additive may saturate, or the transparency of the substrate 201 may decrease.

[0229] An example of a method for producing the film-like substrate 201 according to the first configuration will be described. Here, a method for producing the film-like substrate 201 by a casting method will be described. More specifically, a method for casting resins of the same composition in multiple layers will be described.

[0230] Because PBT has a fast crystallization rate, crystallization progresses even during casting. If PBT is cast as a single layer without being multilayered, there is no barrier to suppress crystal growth, so the crystals grow to a large size, increasing the yield stress of the resulting unstretched raw material. This makes the unstretched raw material more susceptible to breakage when biaxially stretched. Furthermore, the yield stress of the resulting biaxially stretched film is likely to be high, resulting in insufficient formability of the biaxially stretched film. In contrast, if the same resin is used in multiple layers during casting, the stretching stress of the unstretched sheet can be reduced, enabling stable biaxial stretching and lowering the yield stress of the resulting biaxially stretched film, resulting in a flexible film with high breaking strength.

[0231] FIG. 20 is a cross-sectional view showing an example of the layer structure of the substrate 201. When the substrate 201 is produced by casting a resin layer, as shown in FIG. 20, the substrate 201 has a multilayer structure including multiple layers 201a. Each of the multiple layers 201a contains PBT as a main component. For example, each of the multiple layers 201a preferably contains 51% by mass or more of PBT, and more preferably 60% by mass or more of PBT. In the multiple layers 201a, the (n+1)th layer 201a is directly laminated on the nth layer 201a. In other words, no adhesive or bonding layer is interposed between the multiple layers 201a.

[0232] The reason why the properties of PBT film improve when multilayered is speculated to be as follows: When resins are laminated, even if the resin composition is the same, there is an interface between the layers, and this interface accelerates crystallization. On the other hand, the growth of large crystals that exceed the thickness of the layers is suppressed. This is thought to result in a smaller crystal (spherulite) size.

[0233] As a specific method for reducing the size of spherulites by multi-layering, a general multi-layering device (such as a multi-layer feed block, static mixer, or multi-layer multi-manifold) can be used. For example, a method can be used in which thermoplastic resins discharged from different flow paths using two or more extruders are laminated into multiple layers using a feed block, static mixer, or multi-manifold die. Note that when resins of the same composition are multi-layered, it is also possible to use only one extruder and introduce the above-mentioned multi-layering device into the melt line from the extruder to the die.

[0234] The substrate 201 is composed of a multilayer structure portion including at least 10 layers 201a, preferably 60 layers or more, more preferably 250 layers or more, and even more preferably 1000 layers or more. By increasing the number of layers, the size of the spherulites in the PBT in the unstretched raw roll can be reduced, allowing subsequent biaxial stretching to be carried out stably. Furthermore, the yield stress of the PBT in the biaxially stretched film state can be reduced. Preferably, the diameter of the spherulites in the PBT in the unstretched raw roll is 500 nm or less.

[0235] When an unstretched raw PBT is biaxially stretched to produce a biaxially stretched film, the stretching temperature in the machine direction (hereinafter referred to as MD) (hereinafter also referred to as MD stretching temperature) is preferably 40°C or higher, more preferably 45°C or higher. By setting the MD stretching temperature to 40°C or higher, it is possible to prevent the film from breaking. Furthermore, the MD stretching temperature is preferably 100°C or lower, more preferably 95°C or lower. By setting the MD stretching temperature to 100°C or lower, it is possible to prevent the biaxially stretched film from not being oriented.

[0236] The stretching ratio in MD (hereinafter also referred to as MD stretching ratio) is preferably 2.5 times or more. This allows the biaxially stretched film to be oriented, thereby achieving good mechanical properties and a uniform thickness. The MD stretching ratio is, for example, 5 times or less.

[0237] The stretching temperature in the transverse stretching direction (hereinafter also referred to as TD) (hereinafter also referred to as TD stretching temperature) is preferably 40°C or higher. By setting the TD stretching temperature to 40°C or higher, it is possible to prevent the film from breaking. Furthermore, the TD stretching temperature is preferably 100°C or lower. By setting the TD stretching temperature to 100°C or lower, it is possible to prevent the phenomenon in which the biaxially stretched film does not become oriented.

[0238] The stretching ratio in TD (hereinafter also referred to as TD stretching ratio) is preferably 2.5 times or more. This allows the biaxially stretched film to be oriented, thereby achieving good mechanical properties and a uniform thickness. The stretching ratio in MD is, for example, 5 times or less.

[0239] The TD relaxation ratio is preferably 0.5% or more, which can prevent the biaxially stretched PBT film from breaking during heat setting. The TD relaxation ratio is preferably 10% or less, which can prevent the biaxially stretched PBT film from becoming slack and causing thickness unevenness.

[0240] The thickness of layer 201a of substrate 201 shown in Fig. 20 is preferably 3 nm or more, more preferably 10 nm or more, and is preferably 200 nm or less, more preferably 100 nm or less. Furthermore, the thickness of the substrate 201 is preferably 9 μm or more, more preferably 12 μm or more. Furthermore, the thickness of the substrate 201 is preferably 25 μm or less, more preferably 20 μm or less. By making the thickness of the substrate 201 9 μm or more, the substrate 201 has sufficient strength. Furthermore, by making the thickness of the substrate 201 25 μm or less, the substrate 201 exhibits excellent formability. Therefore, the step of manufacturing a packaging bag by processing the packaging material 210 including the substrate 201 can be carried out efficiently.

[0241] [Second configuration of the substrate containing PBT] The substrate 201 according to the second configuration is a monolayer film containing a polyester whose main repeating unit is butylene terephthalate. For example, the substrate 201 includes a homo- or copolymer-type polyester obtained by condensing 1,4-butanediol or its ester-forming derivative as the glycol component and terephthalic acid or its ester-forming derivative as the dibasic acid component. The PBT content in the substrate 201 according to the second configuration is preferably 51% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and most preferably 90% by mass or more. The substrate 201 according to the second configuration is preferably composed only of polybutylene terephthalate and additives.

[0242] In order to impart mechanical strength to the substrate 201, PBTs having a melting point of 200°C or more and 250°C or less and an IV value (intrinsic viscosity) of 1.10 dL / g or more and 1.35 dL / g or less are preferred. Furthermore, PBTs having a melting point of 215°C or more and 225°C or less and an IV value of 1.15 dL / g or more and 1.30 dL / g or less are particularly preferred. These IV values ​​may be satisfied by the entire material constituting the substrate 201. The IV value can be calculated based on JIS K 7367-5:2000.

[0243] The substrate 201 according to the second configuration may contain 30% by mass or less of a polyester resin other than PBT, such as PET. By including PET in addition to PBT in the substrate 201, PBT crystallization can be suppressed, improving the stretchability of the PBT film. The PET blended with the PBT in the substrate 201 can be a polyester whose main repeating unit is ethylene terephthalate. For example, a homotype primarily composed of ethylene glycol as the glycol component and terephthalic acid as the dibasic acid component is preferably used. To impart good mechanical strength properties, PETs with a melting point of 240°C to 265°C and an IV value of 0.55 dl / g to 0.90 dl / g are preferred. Furthermore, PETs with a melting point of 245°C to 260°C and an IV value of 0.60 dl / g to 0.80 dl / g are particularly preferred. By keeping the PET content at 30% by mass or less, it is possible to prevent the rigidity of the unstretched raw material and the stretched film from becoming too high. This prevents the stretched film from becoming brittle, which would reduce the pressure resistance, impact strength, puncture strength, etc. of the stretched film. It also prevents poor stretching when stretching the unstretched raw material.

[0244] The substrate 201 may contain additives such as lubricants, antiblocking agents, inorganic fillers, antioxidants, UV absorbers, antistatic agents, flame retardants, plasticizers, colorants, crystallization inhibitors, and crystallization accelerators, as needed. In order to avoid a decrease in viscosity due to hydrolysis during heat melting, the polyester resin pellets used as the raw material for the substrate 201 are preferably pre-dried sufficiently before heat melting so that the moisture content is 0.05% by weight or less, and preferably 0.01% by weight or less.

[0245] An example of a method for producing the film-like substrate 201 according to the second configuration will be described.

[0246] To stably produce a film of the substrate 201 having the above-described configuration, it is important to suppress crystal growth in the unstretched raw web. Specifically, when cooling an extruded PBT melt to form a film, the crystallization temperature range of the polymer must be cooled at a certain rate or higher; that is, the raw web cooling rate is an important factor. The raw web cooling rate is, for example, 200°C / sec or higher, preferably 250°C / sec or higher, and particularly preferably 350°C / sec or higher. Unstretched raw webs formed into films at high cooling rates maintain a low crystalline state, improving bubble stability during stretching. Furthermore, high-speed film formation is possible, thereby improving film productivity. If the cooling rate is less than 200°C / sec, the resulting unstretched raw web may have high crystallinity and poor stretchability. In extreme cases, the stretching bubbles may burst, preventing the stretching process from continuing.

[0247] The unstretched raw material containing PBT as a main component is preferably transported to the space where biaxial stretching is performed while maintaining the ambient temperature at 25° C. or less, preferably 20° C. or less. This allows the crystallinity of the unstretched raw material immediately after film formation to be maintained even if the residence time is long.

[0248] The biaxial stretching method for stretching an unstretched raw sheet to obtain a stretched film is not particularly limited. For example, by a tubular method or a tenter method, stretching may be performed simultaneously in the longitudinal direction and the transverse direction, or sequentially in the longitudinal direction and the transverse direction. Among these, the tubular method is particularly preferred because it can obtain a stretched film with a good balance of physical properties in the circumferential direction.

[0249] In the tubular method, the unstretched raw film introduced into the stretching space is passed between a pair of low-speed nip rolls and heated by a stretching heater while pressurized air is injected between them. After stretching is completed, air is blown onto the stretched film using a cooling shoulder air ring. Taking into consideration the stretching stability and the strength properties, transparency, and thickness uniformity of the stretched film, the stretching ratio is preferably 2.7 times or more and 4.5 times or less in both MD and TD. By setting the stretching ratio to 2.7 times or more, the tensile modulus and impact strength of the stretched film can be sufficiently ensured. Furthermore, by setting the stretching ratio to 4.5 times or less, excessive molecular chain distortion due to stretching can be suppressed, thereby suppressing the occurrence of breakage or punctures during stretching, thereby enabling the stable production of stretched films.

[0250] The stretching temperature is preferably 40°C or higher and 80°C or lower, and particularly preferably 45°C or higher and 65°C or lower. Because the unstretched raw film produced at the above-mentioned high cooling rate has low crystallinity, it can be stably stretched even at a relatively low stretching temperature. Furthermore, by setting the stretching temperature to 80°C or lower, the fluctuation of the stretching bubble can be suppressed, resulting in a stretched film with good thickness accuracy. Furthermore, by setting the stretching temperature to 40°C or higher, excessive stretch-oriented crystallization due to low-temperature stretching can be suppressed, preventing whitening of the film.

[0251] The substrate 201 produced as described above is composed of a single layer containing, for example, a polyester whose main repeating unit is butylene terephthalate. According to the above-mentioned production method, the unstretched raw material is formed into a film at a high cooling rate, so that even if the unstretched raw material is composed of a single layer, it can maintain a low crystallinity, and therefore the unstretched raw material can be stably stretched.

[0252] The inclusion of PBT in the base material 201 can improve the heat resistance of the barrier laminate film 205 and the heat resistance of the packaging material 210 including the barrier laminate film 205. For example, it can sufficiently increase the tensile modulus of the barrier laminate film 205 and the packaging material 210. In particular, it can sufficiently increase the tensile modulus of the barrier laminate film 205 and the packaging material 210 in a high-temperature atmosphere, for example, an atmosphere of 100°C (hereinafter also referred to as the hot tensile modulus).

[0253] In this embodiment, as in the first embodiment, the packaging material 210 includes a high-stiffness PET film or PBT film, which increases the puncture strength of the packaging material 210. The puncture strength of the packaging material 210 is, for example, 14 N or more, and may be 15 N or more, 16 N or more, 17 N or more, or 18 N or more. Similarly to the first embodiment, the stiffness of the packaging material 210 can be increased. For example, the loop stiffness of the packaging material 210 can be increased. The loop stiffness of the packaging material 210 in at least one direction is, for example, 0.160 N or more, 0.165 N or more, 0.170 N or more, 0.175 N or more, or 0.180 N or more. For example, the loop stiffness of the packaging material 30 in the machine direction (MD) is, for example, 0.160 N or more, and may be 0.165 N or more, 0.170 N or more, 0.175 N or more, or 0.180 N or more. The loop stiffness of the packaging material 30 in the transverse direction (TD) is, for example, 0.160 N or more, and may be 0.165 N or more, 0.170 N or more, 0.175 N or more, or 0.180 N or more.

[0254] [Vapour-deposited layer] Next, the vapor-deposited layer 202 of the barrier laminate film 205 will be described.

[0255] The vapor-deposited layer 202 is a thin film having gas barrier properties that prevent or block the transmission of oxygen gas, water vapor, and the like. The vapor-deposited layer 202 may be a metal layer containing a metal with light-blocking properties such as aluminum, or may be a transparent vapor-deposited layer formed from a transparent inorganic compound. For example, the vapor-deposited layer 202 is a transparent vapor-deposited layer formed from a transparent inorganic oxide.

[0256] The following describes the case where the deposition layer 202 is a transparent deposition layer. The inorganic oxide forming the deposition layer 202 contains, as a main component, an aluminum compound, such as at least aluminum oxide, or aluminum nitride, carbide, or hydroxide, either alone or in combination. For example, the inorganic oxide contains aluminum oxide as a main component. The deposition layer 202 may also be a layer containing a silicon compound as a main component, for example, an inorganic oxide layer containing silicon oxide (silicon oxide) as a main component. Furthermore, the deposition layer 202 may be a layer containing an aluminum compound such as the above-mentioned aluminum oxide as a main component, and further containing a metal oxide such as silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, magnesium oxide, titanium oxide, tin oxide, indium oxide, zinc oxide, or zirconium oxide, or a nitride, carbide, or a mixture thereof of these metals.

[0257] The thickness of the deposition layer 202 is preferably 3 nm or more and 50 nm or less, and more preferably 9 nm or more and 30 nm or less.

[0258] (Gas barrier coating film) The gas barrier coating film 203 of the barrier laminate film 205 serves to mechanically and chemically protect the vapor deposition layer 202 and improve the barrier properties of the barrier laminate film 205 when the vapor deposition layer 202 is a transparent vapor deposition layer, and is laminated so as to be in contact with the vapor deposition layer 202. The gas barrier coating film 203 is a cured film formed from a coating agent for gas barrier coating films, which is made of a resin composition containing a metal alkoxide, a hydroxyl group-containing water-soluble resin, and a silane coupling agent added as needed.

[0259] The mass ratio of the hydroxyl group-containing water-soluble resin to the metal alkoxide in the resin composition is preferably 5 / 95 or more and 20 / 80 or less, and more preferably 8 / 92 or more and 15 / 85 or less. If the mass ratio is less than this range, the barrier effect of the barrier coating layer tends to be insufficient, whereas if the mass ratio is greater than this range, the rigidity and brittleness of the barrier coating layer tends to increase.

[0260] The thickness of the gas barrier coating film 203 is preferably 100 nm or more and 800 nm or less. If it is thinner than the above range, the barrier effect of the gas barrier coating film 203 is likely to be insufficient, and if it is thicker than the above range, it is likely to become too rigid and brittle.

[0261] Metal alkoxides are represented by the general formula R1nM(OR2)m (wherein R1 and R2 represent a hydrogen atom or 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 valence of M. Multiple R1s and R2s in one molecule may be the same or different.) (XI).

[0262] Specific examples of the metal atom represented by M in the metal alkoxide include silicon, zirconium, titanium, aluminum, tin, lead, borane, and others. For example, it is preferable to use an alkoxysilane in which M is Si (silicon).

[0263] In the above general formula (XI), specific examples of OR2 include alkoxy groups such as a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an i-propoxy group, a butoxy group, a 3-methacryloxy group, a 3-acryloxy group, and a phenoxy group, and the like, or a phenoxy group.

[0264] In the above, specific examples of R1 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a phenyl group, a p-styryl group, a 3-chloropropyl group, a trifluoromethyl group, a vinyl group, a γ-glycidoxypropyl group, a methacryl group, and a γ-aminopropyl group.

[0265] Specific examples of alkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraphenoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, methyltriphenoxysilane, phenylphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, dimethyldiethoxysilane, and diphenyldimethoxysilane. Examples of the alkoxysilane include various alkoxysilanes and phenoxysilanes such as methylsilane, diphenyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-chloropropyltriethoxysilane, trifluoromethyltrimethoxysilane, and 1,6-bis(trimethoxysilyl)hexane. In the present embodiment, condensation polymers of these alkoxysilanes can also be used. Specifically, for example, polytetramethoxysilane, polytetraethoxysilane, etc. can be used.

[0266] The silane coupling agent is used to adjust the crosslink density of the cured film made of the metal alkoxide and the hydroxyl group-containing water-soluble resin, thereby providing a film with barrier properties and resistance to hot water treatment.

[0267] The silane coupling agent has the general formula: R3nSi(OR4)4-n (XII) (In the formula, R3 and R4 each independently represent an organic functional group, and n is 1 to 3.) It is expressed as:

[0268] In the general formula (XII), R3 may be, for example, a hydrocarbon group such as an alkyl group or an alkylene group, or a functional group having an epoxy group, a (meth)acryloxy group, a ureido group, a vinyl group, an amino group, an isocyanurate group, or an isocyanate group. Specifically, at least one of the two or three R3 is preferably a functional group having an epoxy group, more preferably a 3-glycidoxypropyl group or a 2-(3,4-epoxycyclohexyl) group. Note that R3 may be the same or different.

[0269] In the general formula (XII), R4 is, for example, an organic functional group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms or an alkoxyalkyl group having 3 to 7 carbon atoms, which may be branched. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, and sec-butyl. Examples of alkoxyalkyl groups having 3 to 7 carbon atoms include groups in which one hydrogen atom has been removed from a straight-chain or branched-chain ether, such as methyl ethyl ether, diethyl ether, methyl propyl ether, methyl isopropyl ether, ethyl propyl ether, ethyl isopropyl ether, methyl butyl ether, ethyl butyl ether, methyl sec-butyl ether, ethyl sec-butyl ether, methyl tert-butyl ether, and ethyl tert-butyl ether. Each (OR4) may be the same or different.

[0270] Examples of silane coupling agents represented by the general formula (XII) above include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane when n = 1. Examples of silane coupling agents represented by the general formula (XII) above include 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane when n = 2, and 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)dimethylmethoxysilane, and 2-(3,4-epoxycyclohexyl)dimethylethoxysilane when n = 3.

[0271] In particular, the crosslink density of the cured film of the barrier coating layer using 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane is lower than that of a system using trialkoxysilane. As a result, the cured film has excellent gas barrier properties and hot water treatment resistance, while also being flexible and has excellent flex resistance, so that packaging materials using this barrier film are resistant to deterioration in gas barrier properties even after a Gelbo Flex test.

[0272] Silane coupling agents where n=1, 2, or 3 can also be used in combination, and the ratio of the amounts and the amount of silane coupling agent used are determined depending on the design of the cured film of the barrier coating layer.

[0273] The hydroxyl group-containing water-soluble resin is capable of dehydration co-condensation with the metal alkoxide, and the saponification degree is preferably 90% or more and 100% or less, more preferably 95% or more and 100% or less, and even more preferably 99% or more and 100% or less. If the saponification degree is lower than the above range, the hardness of the barrier coating layer is likely to decrease.

[0274] Specific examples of hydroxyl group-containing water-soluble resins include polyvinyl alcohol resins, ethylene-vinyl alcohol copolymers, and polymers of bifunctional phenolic compounds and bifunctional epoxy compounds. Each of these may be used alone, in combination with two or more other resins, or copolymerized. Among these, polyvinyl alcohol is particularly preferred due to its excellent flexibility and affinity, and polyvinyl alcohol resins are particularly suitable.

[0275] Specifically, for example, polyvinyl alcohol resins obtained by saponifying polyvinyl acetate, and ethylene-vinyl alcohol copolymers obtained by saponifying copolymers of ethylene and vinyl acetate can be used. Examples of such polyvinyl alcohol resins include PVA-124 (saponification degree = 99%, polymerization degree = 2,400) manufactured by Kuraray Co., Ltd. and Gohsenol NM-14 (saponification degree = 99%, polymerization degree = 1,400) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

[0276] (Preferred Structure of Barrier Laminate Film) Next, a preferred configuration of the barrier laminate film 205 in the thickness direction when the vapor-deposited layer 202 is a transparent vapor-deposited layer containing aluminum oxide will be described with reference to Fig. 22. Fig. 22 shows the results of measuring ions derived from the vapor-deposited layer 202 containing aluminum oxide and ions derived from the substrate 201 using time-of-flight secondary ion mass spectrometry (TOF-SIMS) while repeatedly soft-etching the surface of the barrier laminate film 205 on the gas barrier coating film 203 side at a constant rate using a Cs (cesium) ion gun. The vapor-deposited layer 202 of the barrier laminate film 205 includes a transition region identified by the graphical analysis diagram shown in Fig. 22.

[0277] The transition region is a region between the position T2 of the peak of the element bond Al2O4H that transforms into aluminum hydroxide, detected by etching the barrier laminate film 205 from the gas barrier coating film 203 side using TOF-SIMS, and the interface T1 between the vapor-deposited layer 202 and the substrate 201. The interface T1 between the vapor-deposited layer 202 and the substrate 201 is identified as the position where the intensity of the graph of element C6 is half the intensity of element C6 in the substrate 201. In Figure 22, the symbol W2 represents the thickness of the transition region.

[0278] The ratio of the thickness W2 of the transition region to the thickness of the vapor-deposited layer 202 (hereinafter also referred to as the transformation rate of the transition region) is desirably 5% or more and 60% or less. By setting the transformation rate to 5% or more and 60% or less, it is possible to prevent the barrier properties of the barrier laminate film 205 against water vapor from decreasing when a packaging material including the barrier laminate film 205 is subjected to a sterilization treatment such as boiling or retort treatment. Retort treatment is a process in which a packaging bag made of a packaging material including the barrier laminate film 205 is filled with contents, the packaging bag is sealed, and then the packaging bag is heated under pressure. The temperature of the retort treatment is, for example, 120°C or more. The boiling treatment is a process in which a packaging bag is filled with contents, the packaging bag is sealed, and then the packaging bag is heated in a water bath under atmospheric pressure. The temperature of the boiling treatment is, for example, 90°C or more and 100°C or less. In addition, packaging materials containing a barrier laminate film 205 whose transformation rate in the transition region is 5% or more and 60% or less can effectively function in maintaining barrier properties against gases such as oxygen and water vapor, even when used in packaging bags for applications that do not involve sterilization treatments such as boiling or retort treatment.

[0279] The interface between the substrate 201 and the vapor-deposited layer 202 is subjected to mechanical and chemical stress due to heat. Therefore, in order to prevent a decrease in adhesion and barrier properties, it is important to firmly coat the substrate 201 with the vapor-deposited layer 202 at the interface between the substrate 201 and the vapor-deposited layer 202.

[0280] Due to its chemical structure, aluminum hydroxide has good adhesion to plastic films such as polyester film, and because it forms a dense network of its own, it has high water vapor barrier properties. However, the bond structure based on hydrogen bonds between the aluminum hydroxide and the plastic film is easily microscopically broken down by thermal stress. Furthermore, water molecules easily penetrate the aluminum hydroxide network due to the affinity between the grain boundaries of the aluminum hydroxide.

[0281] In this embodiment, we focus on the elemental bond Al2O4H and control its abundance in order to narrow as much as possible the transition region formed by aluminum hydroxide in the vapor-deposited layer 202 containing aluminum oxide at the interface with the substrate 201. This suppresses aluminum hydroxide generated from the elemental bond Al2O4H due to thermal stress and increases the proportion of the aluminum oxide layer, which contains relatively little aluminum hydroxide, thereby suppressing microscopic destruction of the vapor-deposited layer 202 by water molecules due to thermal stress and destruction of the interface with the plastic film. This makes it possible to provide a barrier laminate film 205 with unprecedented adhesion and barrier properties.

[0282] The deposition layer 202 containing aluminum oxide can be formed by depositing the deposition layer 202 on the surface of the substrate 201 that has been pretreated with oxygen plasma. Various deposition methods can be used to deposit the deposition layer 202, including physical deposition and chemical deposition. The physical deposition method can be selected from the group consisting of evaporation, sputtering, ion plating, ion beam assisted deposition, and cluster ion beam deposition, while the chemical deposition method can be selected from the group consisting of plasma CVD, plasma polymerization, thermal CVD, and catalytic reaction CVD. In this embodiment, the physical deposition method is preferred.

[0283] A specific example of a method for obtaining the graph in Fig. 22 will be described. First, etching is performed from the outermost surface of the gas barrier coating film 203 using Cs, and analysis is performed on the elemental bonds at the interfaces between the gas barrier coating film 203, the vapor deposition layer 202, and films such as the substrate 201, as well as the elemental bonds in the vapor deposition layer 202. This allows the graph shown in Fig. 22 to be obtained.

[0284] Next, a specific example of a method for analyzing the graph of Fig. 22 will be described. Here, a case where the gas barrier coating film 203 contains silicon oxide will be described.

[0285] First, in the graph, the position where the strength of SiO2 (mass number 59.96), a constituent element of the gas barrier coating film 203, is half of the strength in the gas barrier coating film 203 is identified as the interface between the gas barrier coating film 203 and the vapor-deposited layer 202. Next, the position where the strength of C6 (mass number 72.00), a constituent material of the substrate 201, is half of the strength in the substrate 201 is identified as the interface between the substrate 201 and the vapor-deposited layer 202. The distance in the thickness direction between the two interfaces is used as the thickness of the vapor-deposited layer 202.

[0286] Next, the peak of the measured element bond Al2O4H (mass number 118.93) is determined, and the region from that peak to the interface is defined as the transition region. However, if the gas barrier coating film 203 is composed of a material with the same mass number as Al2O4H (mass number 118.93), it is necessary to separate the waveform of 118.93.

[0287] When the reaction product AlSiO4 and hydroxide Al2O4H are produced at the interface between the gas barrier coating film 203 and the vapor-deposited layer 202, they can be separated from the Al2O4H present at the interface between the substrate 201 and the vapor-deposited layer 202. In this way, the separation of the waveforms can be handled appropriately depending on the material of the gas barrier coating film 203.

[0288] In waveform separation, for example, the profile of mass number 118.93 obtained by TOF-SIMS is subjected to nonlinear curve fitting using a Gaussian function, and overlapping peaks can be separated using the least squares Levenberg-Marquardt algorithm.

[0289] While the above analysis assumes a case in which the barrier laminate film 205 includes the substrate 201, the vapor-deposited layer 202, and the gas-barrier coating film 203, the same analysis can also be applied to a case in which the barrier laminate film 205 includes the substrate 201 and the vapor-deposited layer 202 but does not include the gas-barrier coating film 203. Even in cases in which the barrier laminate film 205 does not include the gas-barrier coating film 203, by setting the conversion rate in the transition region of the vapor-deposited layer 202 within a predetermined range, it is possible to prevent a decrease in the barrier properties of the barrier laminate film 205 against water vapor when a packaging material containing the barrier laminate film 205 is subjected to a sterilization treatment such as boiling or retort treatment. When the barrier laminate film 205 includes the substrate 201 and the vapor-deposited layer 202 and etching is performed from the vapor-deposited layer 202 side using time-of-flight secondary ion mass spectrometry (TOF-SIMS), the conversion rate in the transition region of the vapor-deposited layer 202 is preferably 45% or less.

[0290] Next, the mechanical properties of the barrier laminate film 205 will be described. The mechanical properties of the barrier laminate film 205 are mainly determined by the mechanical properties of the substrate 201. For this reason, the mechanical properties of the barrier laminate film 205, such as loop stiffness, puncture strength, tensile strength, tensile elongation, the value obtained by dividing the tensile strength by the tensile elongation, heat shrinkage rate, and tensile modulus, are equivalent to the mechanical properties of the high-stiffness PET film or PBT film that constitutes the substrate 201. Therefore, if the measurement results of the mechanical properties of the barrier laminate film 205 are within the above-mentioned preferred ranges, it is considered that the measurement results of the mechanical properties of the substrate 201 alone, which is constituted by the high-stiffness PET film or PBT film, will also be within the above-mentioned preferred ranges.

[0291] [Sealant layer] Next, the sealant layer 212 will be described. The sealant layer 212 is a layer containing a thermoplastic resin that constitutes the inner surface 210x of the packaging material 210. In the example shown in FIG. 18, the sealant layer 212 is formed by bonding a thermoplastic resin film to a stretched plastic film 214 via a second adhesive layer 215. In the example shown in FIG. 19, the sealant layer 212 is formed by bonding a thermoplastic resin film to the base material 201 of the barrier laminate film 205 via the second adhesive layer 215. Although not shown, the sealant layer 212 may also be formed by extruding a thermoplastic resin onto the stretched plastic film 214 or the barrier laminate film 205.

[0292] The material constituting the sealant layer 212 can be one or more resins selected from polyethylene, such as low-density polyethylene and linear low-density polyethylene, and polypropylene. The sealant layer 212 may be a single layer or a multilayer. The sealant layer 212 is preferably made of an unstretched film. The term "unstretched" encompasses not only a film that is not stretched at all, but also a film that is slightly stretched due to the tension applied during film formation.

[0293] Incidentally, a packaged product made of the packaging material 210 having the sealant layer 212 may be subjected to a sterilization treatment such as boiling or retort treatment at high temperatures. Therefore, the sealant layer 212 used has heat resistance that can withstand such high-temperature treatments.

[0294] The melting point of the material constituting sealant layer 212 is preferably 150°C or higher, and more preferably 160°C or higher. Increasing the melting point of sealant layer 212 makes it possible to perform retort processing of the packaged product at a high temperature, thereby shortening the time required for retort processing. Note that the melting point of the material constituting sealant layer 212 is lower than the melting point of the resin constituting base material 201.

[0295] From the viewpoint of retort treatment, a material containing propylene as a main component can be used as the material for the sealant layer 212, as in the case of the sealant layer 70 in the first embodiment described above. Furthermore, from the viewpoint of boiling treatment, examples of the material for the sealant layer 212 include polyethylene, polypropylene, or a combination thereof, as in the case of the sealant layer 70 in the first embodiment described above.

[0296] Preferably, the sealant layer 212 contains a propylene-ethylene block copolymer, as in the case of the sealant layer 70 in the first embodiment described above. For example, the sealant film constituting the sealant layer 212 is an unstretched film whose main component is a propylene-ethylene block copolymer. By using a propylene-ethylene block copolymer, the impact resistance of the sealant layer can be increased, thereby preventing the packaged product from breaking due to an impact when dropped. Furthermore, the puncture resistance of the packaging material 210 can be increased.

[0297] Furthermore, the sealant layer 212 may further contain a thermoplastic elastomer, as in the case of the sealant layer 70 in the first embodiment described above. By using a thermoplastic elastomer, the impact resistance and puncture resistance of the sealant layer can be further improved.

[0298] The content of the propylene-ethylene block copolymer in the sealant layer 212 is, for example, 80% by mass or more, and preferably 90% by mass or more.

[0299] Propylene-ethylene block copolymers can be produced by polymerizing the raw materials propylene and ethylene using a catalyst, such as a Ziegler-Natta catalyst or a metallocene catalyst.

[0300] The sealant layer 212 may have easy-peel properties. Easy-peel properties refer to the property that, when a packaging material 210 having a sealant layer 212 is used to form a lid for a container, the lid can be easily peeled from the flange of the container at its underside, i.e., at the sealant layer 212. Easy-peel properties can be achieved, for example, by forming the sealant layer 212 from two or more types of resins, with one resin being incompatible with the other resins. Examples of resins that can achieve easy-peel properties include mixed resins of polyethylene and polypropylene, such as high-density polyethylene.

[0301] When the sealant layer 212 has easy-peel properties, as shown in FIG. 21 , the sealant layer 212 may include a first layer 2121 that constitutes the inner surface 210x of the packaging material 210 and a second layer 2122 that is located closer to (outside of) the barrier laminate film 205 than the first layer 2121. In this case, the first layer 2121 may be a layer containing a mixture of polypropylene and high-density polyethylene. The second layer 2122 may be a layer made of polypropylene or high-density polyethylene. Such a sealant layer 212 may be formed by bonding a co-extruded film including the first layer 2121 and the second layer 2122 to the barrier laminate film 205. When the second layer 2122 is made of polypropylene, the sealant layer 212 including the first layer 2121 and the second layer 2122 has heat resistance that allows it to withstand heat treatment up to, for example, 135°C. Furthermore, when the second layer 2122 is made of high density polyethylene, the sealant layer 212 including the first layer 2121 and the second layer 2122 has heat resistance that allows it to withstand heat treatment up to 123°C, for example.

[0302] The sealant layer 212 may or may not contain a biomass-derived component. When the sealant layer 212 is formed from a material containing a biomass-derived component, the sealant layer 212 can be formed using the biomass polyolefin described below. When the sealant layer 212 is formed from a material not containing a biomass-derived component, the sealant layer 212 can be formed using a conventionally known thermoplastic resin derived from fossil fuels. Note that, like the sealant layer 212 of this embodiment, the sealant layer 70 of the first embodiment described above may or may not contain a biomass-derived component.

[0303] Biomass polyolefin is a polymer of monomers containing olefins such as ethylene derived from biomass. Since biomass-derived olefins are used as the raw material monomers, the polyolefins obtained by polymerization are derived from biomass. Note that the raw material monomers for polyolefins do not necessarily contain 100% by mass of biomass-derived olefins.

[0304] For example, biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use biomass-derived fermented ethanol obtained from plant raw materials. The plant raw material is not particularly limited, and conventionally known plants can be used. Examples include corn, sugarcane, beet, and manioc.

[0305] Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from plant raw materials with an ethanol-producing microorganism or a product derived from its disruption, followed by purification. Ethanol can be purified from the culture solution by conventional methods such as distillation, membrane separation, and extraction. Examples of methods include adding benzene, cyclohexane, etc., followed by azeotropy, or removing water by membrane separation.

[0306] The monomers that are the raw material for biomass polyolefin may further include ethylene monomers derived from fossil fuels and / or α-olefin monomers derived from fossil fuels, or may further include α-olefin monomers derived from biomass.

[0307] The number of carbon atoms in the α-olefin is not particularly limited, but those having 3 to 20 carbon atoms can usually be used, and butylene, hexene, or octene is preferred. This is because butylene, hexene, or octene can be produced by polymerizing ethylene, a raw material derived from biomass. Furthermore, by including such an α-olefin, the polyolefin obtained by polymerization has alkyl groups as a branched structure, and can therefore be more flexible than a simple linear one.

[0308] As the biomass polyolefin, polyethylene or a copolymer of ethylene and an α-olefin may be used alone or in combination. In particular, polyethylene is preferred as the biomass polyolefin. This is because, by using ethylene, a raw material derived from biomass, it is theoretically possible to produce a polyolefin from 100% biomass-derived components.

[0309] The biomass polyolefin may contain two or more kinds of biomass polyolefins having different biomass degrees, and it is sufficient that the biomass degree of the entire polyolefin resin layer falls within the range described below.

[0310] The biomass polyolefin preferably has a viscosity of 0.91 g / cm 3 More than 0.93g / cm 3 or less, more preferably 0.912 g / cm 3 More than 0.928g / cm 3 or less, more preferably 0.915 g / cm 3 More than 0.925g / cm 3The density of biomass polyolefin is a value measured according to the method specified in Method A of JIS K7112-1980 after annealing as specified in JIS K6760-1995. 3 If the density of the biomass polyolefin is 0.93 g / cm or more, the rigidity of the polyolefin resin layer containing the biomass polyolefin can be increased, and the polyolefin resin layer can be suitably used as an inner layer of a packaging product. 3 If the content is below this level, the transparency and mechanical strength of the polyolefin resin layer containing biomass polyolefin can be increased, and the polyolefin resin layer can be suitably used as an inner layer of a packaging product.

[0311] The biomass polyolefin has a melt flow rate (MFR) of 0.1 g / 10 min to 10 g / 10 min, preferably 0.2 g / 10 min to 9 g / 10 min, and more preferably 1 g / 10 min to 8.5 g / 10 min. The melt flow rate is a value measured by Method A under conditions of a temperature of 190°C and a load of 21.18 N in accordance with the method specified in JIS K7210-1995. If the MFR of the biomass polyolefin is 0.1 g / 10 min or more, the extrusion load during molding can be reduced. Furthermore, if the MFR of the biomass polyolefin is 10 g / 10 min or less, the mechanical strength of the polyolefin resin layer containing the biomass polyolefin can be increased.

[0312] A suitable biomass polyolefin is a biomass-derived low-density polyethylene (product name: SBC818, density: 0.918 g / cm) manufactured by Braskem. 3 , MFR: 8.1 g / 10 min, biomass content: 95%), Braskem biomass-derived low-density polyethylene (trade name: SPB681, density: 0.922 g / cm 3 , MFR: 3.8 g / 10 min, biomass content: 95%), Braskem biomass-derived linear low-density polyethylene (trade name: SLL118, density: 0.916 g / cm 3, MFR: 1.0 g / 10 min, biomass content 87%).

[0313] Examples of the fossil fuel-derived thermoplastic resin include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, propylene-ethylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and ionomer.

[0314] The sealant layer 212 preferably has a biomass ratio of 5% or more, more preferably 5% to 60%, and even more preferably 10% to 60%. If the biomass ratio is within the above range, the amount of fossil fuel used can be reduced, and the environmental load can be reduced.

[0315] As described above, the sealant layer 212 may be a single layer or multiple layers. When the biomass polyolefin described above is used for the sealant layer, the sealant layer may have three layers: an inner layer, an intermediate layer, and an outer layer. In this case, it is preferable that the intermediate layer be a layer made of biomass polyolefin or a layer made of a mixture of biomass polyolefin and a conventionally known polyolefin derived from fossil fuels, and the inner and outer layers be made of conventionally known polyolefin derived from fossil fuels.

[0316] The thickness of the sealant layer 212 is preferably 30 μm or more, and more preferably 40 μm or more, and is preferably 100 μm or less, and more preferably 80 μm or less.

[0317] [Stretched plastic film] The stretched plastic film 214 is a plastic film that is stretched in a predetermined direction. The stretched plastic film 214 may be a uniaxially stretched film that is stretched in one predetermined direction, or a biaxially stretched film that is stretched in two predetermined directions. The stretching direction of the stretched plastic film 214 is not particularly limited. For example, the stretched plastic film 214 may be stretched in the machine direction (MD) of the film, or may be stretched in the transverse direction (TD) perpendicular to the machine direction.

[0318] Various plastics such as polyethylene, polypropylene, polyamide, polyvinyl chloride, polystyrene, and polyester can be used as the material for the stretched plastic film 214. For example, the stretched plastic film 214 is a polyester film or a polyamide film. The stretched plastic film 214 may also be a high-stiffness PET film or PBT film, similar to the substrate 201 of the barrier laminate film 205.

[0319] The stretched plastic film 214 may contain a biomass-derived component. For example, the stretched plastic film 214 may contain a resin composition containing a biomass-derived polyester (hereinafter also referred to as biomass polyester). When the stretched plastic film 214 contains a biomass-derived component, the biomass content in the stretched plastic film 214 is preferably 5.0% or more, more preferably 10.0% or more, and may be 15.0% or more. Furthermore, the biomass content of the stretched plastic film 214 is preferably 30.0% or less, and may be 25.0% or less.

[0320] Biomass polyester is a polyester in which the diol unit is biomass-derived ethylene glycol and the dicarboxylic acid unit is fossil fuel-derived dicarboxylic acid. Biomass-derived ethylene glycol has the same chemical structure as conventional fossil fuel-derived ethylene glycol, so polyester films synthesized using biomass-derived ethylene glycol are comparable in physical properties, such as mechanical properties, to conventional fossil fuel-derived polyester films. Therefore, the stretched plastic film 214 and the packaging material 210 comprising it have a layer made of a carbon-neutral material, and therefore can reduce the amount of fossil fuel used and the environmental impact compared to stretched plastic films and packaging materials comprising them made from raw materials obtained from conventional fossil fuels.

[0321] Alternatively, the stretched plastic film 214 may be a recycled film containing polyethylene terephthalate recycled by mechanical recycling. The recycled film contains PET obtained by mechanically recycling PET bottles, and this PET contains ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as dicarboxylic acid units. Here, mechanical recycling generally refers to a method in which collected polyethylene terephthalate resin products such as PET bottles are crushed and washed with alkali to remove surface dirt and foreign matter from the PET resin product, and then dried at high temperature and reduced pressure for a certain period of time to diffuse and decontaminate contaminants remaining inside the PET resin, thereby removing the dirt from the resin product made of PET resin and returning it to PET resin.

[0322] When the stretched plastic film 214 includes a stretched polyester film such as a stretched polyethylene terephthalate film or a stretched polybutylene terephthalate film, the thickness of the stretched plastic film 214 is, for example, 9 μm or more and 25 μm or less. When the stretched plastic film 214 includes a stretched polyamide film such as a stretched nylon film, the thickness of the stretched plastic film 214 is, for example, 15 μm or more and 25 μm or less.

[0323] [Adhesive layer] The first adhesive layer 213 is a layer that bonds the plastic film that constitutes the outer surface 210y of the packaging material 210 to a plastic film located in the middle of the packaging material 210. The second adhesive layer 215 is a layer that bonds the plastic film located in the middle of the packaging material 210 to the sealant layer 212. The first adhesive layer 213 and the second adhesive layer 215 are adhesive layers or adhesive resin layers. The adhesive layer and adhesive resin layer will be described below.

[0324] The adhesive layer can be formed by a conventional method, such as a dry lamination method. When two layers are bonded by the dry lamination method, the adhesive layer is formed by applying an adhesive to the surface of the layer to be laminated and drying it. Examples of adhesives that can be applied include one-component or two-component curing or non-curing vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, and other solvent-based, water-based, or emulsion-based adhesives. Two-component curing adhesives can include cured products of polyols and isocyanate compounds. Examples of coating methods for the laminating adhesive include direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fountain coating, transfer roll coating, and other methods. The adhesive layer after drying has a thickness of, for example, 1 μm to 10 μm, preferably 2 μm to 5 μm.

[0325] The adhesive layer may contain a biomass-derived component. For example, when the adhesive layer contains a cured product of a polyol and an isocyanate compound, at least one of the polyol and the isocyanate compound may contain a biomass-derived component. This can further improve the biomass content of the packaging material 210.

[0326] The adhesive resin layer contains a thermoplastic resin. The adhesive resin layer can be formed by a conventionally known method, such as a melt extrusion lamination method or a sand lamination method. Examples of the thermoplastic resin that can be used for the adhesive resin layer include polyethylene resins, polypropylene resins, cyclic polyolefin resins, copolymer resins, modified resins, and mixtures (including alloys) containing these resins as the main components. Examples of polyolefin resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), ethylene-α-olefin copolymers polymerized using metallocene catalysts, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. To improve interlayer adhesion, acid-modified polyolefin resins can be used, which are modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid. Furthermore, resins obtained by graft polymerization or copolymerization of unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers onto polyolefin resins can also be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more. The adhesive resin layer has a thickness of, for example, 5 μm to 50 μm, preferably 10 μm to 30 μm.

[0327] The polyethylene resin may be one that uses biomass-derived ethylene as a monomer unit, as described for the sealant layer 212. This can further improve the biomass content of the packaging material 210.

[0328] [Print layer] The printing layer 218 is a layer on which any desired printed pattern such as letters, numbers, pictures, figures, symbols, or designs is formed for decoration, indication of the contents or packaged product, indication of the expiration date, indication of the manufacturer or seller, or other indication or aesthetic purposes. The printing layer 218 can be provided as needed, and can be provided, for example, on a film including the barrier laminate film 205 or a film including the stretched plastic film 214. The printing layer 218 may be provided on the entire surface of the film or on a part of it. The printing layer 218 can be formed using conventionally known pigments or dyes, and the method of forming it is not particularly limited.

[0329] The printing layer 218 preferably has a thickness of 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, and even more preferably 1 μm or more and 3 μm or less.

[0330] The printed layer 218 may contain a biomass-derived component. For example, when the printed layer 218 contains a cured product of a polyol and an isocyanate compound, at least one of the polyol and the isocyanate compound may contain the biomass-derived component.

[0331] <Manufacturing method of packaging materials> Next, an example of a method for producing the packaging material 210 will be described. First, an example of a method for producing the barrier laminate film 205 will be described.

[0332] (Barrier laminate film manufacturing process) First, a substrate 201 is prepared. Then, a vapor deposition layer 202 containing aluminum oxide is formed on the surface of the substrate 201. Fig. 23 is a diagram showing an example of a film formation apparatus 260. The film formation apparatus 260 and a film formation method using the film formation apparatus 260 will be described below.

[0333] 23, in the film formation apparatus 260, partition walls 285a to 285c are formed in the decompression chamber 262. The partition walls 285a to 285c form a substrate transfer chamber 262A, a plasma pre-treatment chamber 262B, and a film formation chamber 262C, and in particular, the plasma pre-treatment chamber 262B and the film formation chamber 262C are formed as spaces surrounded by the partition walls and the partition walls 285a to 285c, and each chamber further has an exhaust chamber formed therein as necessary.

[0334] The plasma pretreatment chamber 262B and the plasma pretreatment process therein will now be described. A plasma pretreatment roller 270, which transports the substrate 201 to be pretreated and enables plasma treatment, is provided in the plasma pretreatment chamber 262B so that a portion of the roller 270 is exposed to the substrate transport chamber 262A. The substrate 201 is transported to the plasma pretreatment chamber 262B while being wound up.

[0335] The plasma pretreatment chamber 262B and the film formation chamber 262C are provided adjacent to the substrate transfer chamber 262A, allowing the substrate 201 to be moved without being exposed to the atmosphere. The pretreatment chamber 262B and the substrate transfer chamber 262A are connected by a rectangular hole, through which a portion of the plasma pretreatment roller 270 protrudes toward the substrate transfer chamber 262A, leaving a gap between the wall of the transfer chamber and the pretreatment roller 270, allowing the substrate 201 to be moved from the substrate transfer chamber 262A to the film formation chamber 262C through the gap. The same structure is also provided between the substrate transfer chamber 262A and the film formation chamber 262C, allowing the substrate 201 to be moved without being exposed to the atmosphere.

[0336] The substrate transport chamber 262A is provided with a winding roller as a winding means for winding up the substrate 201, which has been moved again to the substrate transport chamber 212A by the deposition roller 275 and has a deposition layer 202 formed on one side, into a roll, so that the substrate 201, on which the deposition layer 202 has been formed, can be wound up.

[0337] When producing a barrier laminate film 205 having a vapor-deposited layer 202 containing aluminum oxide, the plasma pretreatment chamber 262B is configured to separate the space where plasma is generated from other areas and to efficiently evacuate the opposing space, thereby facilitating control of the plasma gas concentration and improving productivity. The reduced pretreatment pressure can be set and maintained at approximately 0.1 Pa to 100 Pa, and in particular, the treatment pressure for oxygen plasma pretreatment is preferably 1 to 20 Pa to achieve a preferred transformation rate in the transition region of the vapor-deposited layer 202 containing aluminum oxide.

[0338] The conveying speed of the substrate 201 is not particularly limited, but from the viewpoint of production efficiency, it can be at least 200 to 1000 m / min. In particular, a conveying speed of 300 to 800 m / min is preferable for oxygen plasma pretreatment in order to achieve a transformation rate in the transition region of the deposition layer 202 containing aluminum oxide.

[0339] The plasma pretreatment roller 270 constituting the plasma pretreatment device is intended to prevent shrinkage or damage to the substrate 201 due to heat during plasma treatment by the plasma pretreatment means, and to apply oxygen plasma P uniformly and widely to the substrate 201. It is preferable that the pretreatment roller 270 can be adjusted to a constant temperature between -20°C and 100°C by adjusting the temperature of a temperature control medium circulating inside the pretreatment roller.

[0340] The plasma pretreatment means includes a plasma supply means and a magnetic forming means, and cooperates with the plasma pretreatment roller 270 to confine the oxygen plasma P near the surface of the substrate 201.

[0341] The plasma pretreatment means is provided so as to cover a portion of the pretreatment roller 270. Specifically, the plasma pretreatment means is configured by a plasma supply means 272 and a magnetic field generating means 273 arranged along the surface of the pretreatment roller 270 near its outer periphery. The plasma supply means 272 includes a plasma supply nozzle that supplies plasma raw material gas. The magnetic field generating means 273 has a magnet or the like to promote the generation of plasma P. The plasma pretreatment means also has an electrode 271 to which a voltage is applied between the pretreatment roller 270 and the electrode 271. Note that FIG. 23 shows an example in which the electrode 271 and the plasma supply means 272 are separate members, but this is not limiting. Although not shown, the electrode 271 and the plasma supply means 272 may be configured as an integrated member.

[0342] By generating plasma P in the space between the pretreatment roller 270 and the magnetic forming means 273 and forming a region of high plasma density near the surface of the pretreatment roller 270 and the substrate 201, oxygen plasma pretreatment can be performed on the inner surface of the substrate 201 to form a plasma-treated surface.

[0343] The plasma supply means 272 of the plasma pretreatment means includes a raw material gas volatilization supply device 268 connected to a plasma supply nozzle provided outside the decompression chamber 262, and a raw material gas supply line for supplying the raw material gas from the device. The plasma raw material gas to be supplied is oxygen alone or a mixed gas of oxygen gas and an inert gas, which is supplied from a gas reservoir via a flow controller while the gas flow rate is measured. The inert gas may be one or a mixed gas of two or more selected from the group consisting of argon, helium, and nitrogen.

[0344] These supplied gases are mixed at a predetermined ratio as needed to form a plasma raw material gas alone or a plasma-forming mixed gas, which is then supplied to the plasma supply means. The single gas or mixed gas is supplied to the plasma supply nozzle of the plasma supply means and supplied near the outer periphery of the pretreatment roller 270, where the supply port of the plasma supply nozzle opens. The nozzle opening is directed toward the substrate 201 on the pretreatment roller 270, and is positioned and configured to enable oxygen plasma P to be diffused and supplied uniformly over the entire surface of the substrate 201. This allows uniform plasma pretreatment to be performed over a large area of ​​the substrate 201.

[0345] To achieve the above-mentioned conversion rate of the transition region of the deposited layer 202 containing aluminum oxide of 5% to 60%, the oxygen plasma pretreatment preferably uses a mixture ratio of oxygen gas to inert gas (oxygen gas / inert gas) of 6 / 1 to 1 / 1, more preferably 5 / 2 to 3 / 2. By setting the mixture ratio to 6 / 1 to 1 / 1, the film formation energy of the deposited layer 202 on the substrate 201 increases, and by setting the mixture ratio to 5 / 2 to 3 / 2, aluminum hydroxide is formed near the interface of the substrate, i.e., the conversion rate of the transition region decreases.

[0346] Electrode 271 functions as an opposing electrode to pretreatment roller 270. The supplied plasma raw material gas is excited by a potential difference caused by a high-frequency voltage, a low-frequency voltage, or the like supplied between electrode 271 and pretreatment roller 270, and plasma P is generated and supplied.

[0347] Specifically, the electrode 271 is provided with a plasma pretreatment roller as a plasma power source, and an AC voltage with a frequency of 10 Hz to 2.5 GHz is applied between the opposing electrode, and input power control or impedance control or the like is performed to make it possible to apply any voltage between the electrode 271 and the plasma pretreatment roller 270. The film forming apparatus 260 is equipped with a power source 282 that can apply a bias voltage to make the oxygen plasma P, which can physically or chemically modify the surface properties of the substrate 201, positively charged.

[0348] The plasma intensity per unit area is preferably 50 to 8000 W·sec / m 2 50W·sec / m 2 Below this, the effect of plasma pretreatment is not observed, and 2 Above this level, the substrate 201 tends to be deteriorated by the plasma, such as worn, damaged, discolored, or burned. In particular, the plasma intensity per unit area is 100 to 1000 W·sec / m 2 By applying a bias voltage perpendicular to the substrate 201 and applying the above-mentioned plasma intensity, it is possible to stably improve the adhesion to the deposition layer 202 containing aluminum oxide.

[0349] The magnetic forming means 273 may be a magnet case with an insulating spacer and a base plate provided inside, with a magnet attached to the base plate. An insulating shield plate may be provided on the magnet case, with an electrode attached to the insulating shield plate. The magnet case and the electrode are electrically insulated, and even if the magnet case is installed and fixed in the decompression chamber 262, the electrode can be kept at an electrically floating level. The provision of a magnet increases reactivity near the surface of the substrate 201, making it possible to form a good plasma pre-treated surface at high speed.

[0350] Preferably, the magnet is configured so that the magnetic flux density at the surface of the substrate 201 is 10 to 10,000 gauss. If the magnetic flux density at the surface of the substrate 201 is 10 gauss or more, it is possible to sufficiently increase the reactivity near the surface of the substrate 201, and a good pre-treated surface can be formed at high speed.

[0351] Next, the film formation chamber 262C and the film formation process in the film formation chamber 262C will be described. The film formation apparatus 260 has a film formation roller 275 arranged in the reduced-pressure film formation chamber 262C and a target of a vapor deposition film formation means 274 arranged opposite the film formation roller 275. The film formation roller 275 wraps around and transports the substrate 201 with the treated surface of the substrate 201, which has been pretreated in the plasma pretreatment device, facing outward. In the film formation process, the target of the vapor deposition film formation means 274 is evaporated to form an aluminum oxide film on the surface of the substrate 201.

[0352] The vapor deposition film forming means 274 is, for example, a resistance heating type, and uses aluminum as an evaporation source, an aluminum metal wire, and supplies oxygen to oxidize the aluminum vapor, thereby forming a vapor deposition layer 202 containing aluminum oxide on the surface of the substrate 201.

[0353] The thickness of the deposited layer 202 containing aluminum oxide formed as described above is preferably 3 to 50 nm, and more preferably 9 to 30 nm. Within this range, the barrier properties can be maintained. However, if the deposited layer 202 containing aluminum oxide is very thin, it becomes difficult to calculate the transformation rate in the transition region by TOF-SIMS measurement.

[0354] Next, a method for forming the gas barrier coating film 203 on the vapor deposition layer 202 will be described. First, the above-mentioned metal alkoxide, silane coupling agent, hydroxyl group-containing water-soluble resin, reaction accelerator (sol-gel catalyst, acid, etc.), and organic solvent such as water or alcohol (e.g., methyl alcohol, ethyl alcohol, isopropanol, etc.) as a solvent are mixed to prepare a coating agent for the gas barrier coating film made of a resin composition.

[0355] When the gas barrier coating film 203 contains a silane coupling agent, the coating agent for the gas barrier coating film may be prepared as follows. First, a metal alkoxide such as alkoxysilane is mixed with the silane coupling agent. The metal alkoxide and the silane coupling agent are preferably mixed at 10°C or less. This makes it easier for the film structure of the gas barrier coating film 203 to be formed to be dense. Next, the mixture of the metal alkoxide and the silane coupling agent is mixed with a hydroxyl group-containing water-soluble resin such as a polyvinyl alcohol resin.

[0356] After preparing the coating agent for a gas barrier coating film, the coating agent for a gas barrier coating film is applied to the vapor deposition layer 202 by a conventional method and dried. This drying step further promotes the condensation or co-condensation reaction, forming a coating film. The above coating operation may be further repeated on the first coating film to form multiple coating films consisting of two or more layers.

[0357] Further, the substrate 201 is heat-treated for 3 seconds to 10 minutes at a temperature in the range of 20 to 200°C, preferably 50 to 180°C, and at a temperature not higher than the softening point of the resin constituting the substrate 201. This makes it possible to form a gas barrier coating film 203 made of the coating agent for gas barrier coating films on the vapor deposition layer 202. In this way, a barrier laminate film 205 having the substrate 201, vapor deposition layer 202, and gas barrier coating film 203 can be produced.

[0358] (Lamination process) Next, a method for producing the above-mentioned packaging material 210 by laminating the barrier laminate film 205 with other films will be described.

[0359] An example of a method for producing the packaging material 210 shown in FIG. 18 will be described. First, a barrier laminate film 205 is prepared, and a printed layer 218 is formed on the gas barrier coating film 203 of the barrier laminate film 205, for example, by gravure printing. A stretched plastic film 214 is also prepared. Then, by dry lamination, a film including the barrier laminate film 205 on which the printed layer 218 is provided is bonded to the stretched plastic film 214 via a first adhesive layer 213 made of an adhesive layer. A film constituting the sealant layer 212 is also prepared. Then, by dry lamination, a laminate including the barrier laminate film 205 and the stretched plastic film 214 is bonded to the film constituting the sealant layer 212 via a second adhesive layer 215 made of an adhesive layer. In this manner, the packaging material 210 shown in FIG. 18 can be obtained. After the stretched plastic film 214 and the film that constitutes the sealant layer 212 are bonded together, the laminate including the stretched plastic film 214 and the sealant layer 212 and the barrier laminate film 205 may be bonded together.

[0360] An example of a method for manufacturing the packaging material 210 shown in FIG. 19 will be described. First, a stretched plastic film 214 is prepared, and a printed layer 218 is formed on the stretched plastic film 214, for example, by gravure printing. A barrier laminate film 205 is also prepared. Thereafter, the stretched plastic film 214 with the printed layer 218 formed thereon and the barrier laminate film 205 are bonded together by dry lamination via a first adhesive layer 213 made of an adhesive layer. A film constituting the sealant layer 212 is also prepared. Thereafter, a laminate including the stretched plastic film 214 and the barrier laminate film 205 is bonded to the film constituting the sealant layer 212 via a second adhesive layer 215 made of an adhesive layer by dry lamination. In this manner, the packaging material 210 shown in FIG. 19 can be obtained. After the barrier laminate film 205 and the film that constitutes the sealant layer 212 are bonded together, the laminate including the barrier laminate film 205 and the sealant layer 212 and the stretched plastic film 214 may be bonded together.

[0361] <Packaging products> Examples of packaging products formed using packaging material 210 include, as in the first embodiment described above, the bag 10 shown in Figures 1, 15, and 16, and the lid material 114 of the lidded container 110 shown in Figures 17A and 17B.

[0362] Bags for packaged products can be produced by folding the packaging material 210 in half, or by preparing two sheets of packaging material 210 and overlapping them with the sealant layer 212 of the front packaging material 210 facing the sealant layer 212 of the back packaging material 210, and then heat-sealing the peripheral edges using a heat seal method such as a side seal, two-sided seal, three-sided seal, four-sided seal, envelope seal, hem seal (pillow seal), pleated seal, flat bottom seal, or square bottom seal. Also, a gusset-type bag can be produced by inserting a folded-over packaging material 210 between the front and back packaging materials 210 and heat-sealing the materials. It is not necessary for all of the packaging materials 210 constituting the bag to be the packaging material 210 of the present invention. That is, it is sufficient that at least a portion of the packaging material 210 constituting the bag is a packaging material 210 comprising a barrier laminate film 205 having a substrate 201 comprising a high-stiffness PET film or PBT film, and the other portion of the packaging material 210 constituting the bag may be a packaging material 210 that does not comprise a barrier laminate film 205.

[0363] Heat sealing can be performed by any known method, such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, or ultrasonic sealing.

[0364] At least one of the films constituting the bag 10 as shown in Figures 1, 15, and 16, such as the front film 14, back film 15, and bottom film 16, is made of a packaging material 210 including a barrier laminate film 205 having a substrate 201 including a high-stiffness PET film or PBT film. This provides the bag with gas barrier properties and strength. Similarly, the lid member 114 constituting the lidded container 110 as shown in Figures 17A and 17B can also be made of a packaging material 210 including a barrier laminate film 205 having a substrate 201 including a high-stiffness PET film or PBT film. This provides the lidded container with gas barrier properties and strength.

[0365] For example, as in the first embodiment, the packaging material 210 and the packaged product can be made puncture resistant. This makes it possible to prevent the packaged product from being torn when a sharp object with a pointed tip comes into contact with the packaged product. The puncture strength of the packaging material 210 is preferably 14 N or more, more preferably 15 N or more, even more preferably 16 N or more, preferably 17 N or more, and even more preferably 18 N or more.

[0366] Furthermore, as in the first embodiment, the packaging material 210 can be provided with rigidity. The loop stiffness of the packaging material 210 in the machine direction (MD) is, for example, 0.150 N or more, or may be 0.160 N or more, 0.170 N or more, or 0.180 N or more. The loop stiffness of the packaging material 210 in the transverse direction (TD) is, for example, 0.150 N or more, or may be 0.160 N or more, 0.170 N or more, or 0.180 N or more. Therefore, when filling a bag 10 as shown in FIG. 14 made using the packaging material 210 with contents, the opening 11b can be easily formed in the upper portion 11 by moving the zipper portion 19 as shown in FIG. 14. For example, the front surface film 14 and the back surface film 15 can easily deform to have a curved shape that is convex on the outer surface side. This makes it easier to ensure the opening width K of the opening 11b. Also in this embodiment, since the packaging material 210 has rigidity, wrinkles are less likely to occur in the front film 14 and the back film 15. This makes it easier for the suction portion 106 to adhere to the outer surfaces of the front film 14 and the back film 15. This can also contribute to ensuring the opening width K of the opening 11b. [Example]

[0367] Next, the present invention will be explained in more detail with reference to examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[0368] Examples A1 to A6, reference example A7~A8 and Comparative Example A1, the puncture strength, tearing property and heat resistance of the packaging material 30 of the present invention were evaluated.

[0369] (Example A1) A high-stiffness polyester film made of PET (hereinafter also referred to as high-stiffness PET film) having a loop stiffness of 0.0017 N or more was prepared as the first stretched plastic film 40. Subsequently, a printed layer 32 having a thickness of 1 μm was formed on the surface of the high-stiffness PET film. Specifically, XP-55 manufactured by Toray Industries, Inc. was used as the high-stiffness PET film. The thickness of the high-stiffness PET film was 16 μm. The measured loop stiffness of the high-stiffness PET film was 0.0021 N in both the machine direction and the perpendicular direction. The tensile modulus of the high-stiffness PET film in the machine direction was 4.8 GPa, and the tensile modulus of the high-stiffness PET film in the perpendicular direction was 4.7 GPa. The tensile strength of the high-stiffness PET film in the machine direction was 292 MPa, and the tensile strength of the high-stiffness PET film in the perpendicular direction was 257 MPa. The tensile elongation of the high-stiffness PET film in the machine direction was 107%, and the tensile elongation of the high-stiffness PET film in the perpendicular direction was 102%. In this case, the tensile strength of the high-stiffness PET film in the machine direction divided by the tensile elongation was 2.73 [MPa / %], and the tensile strength of the high-stiffness PET film in the perpendicular direction divided by the tensile elongation was 2.52 [MPa / %]. The heat shrinkage of the high-stiffness PET film in both the machine direction and the perpendicular direction was 0.4%.

[0370] Furthermore, a straight-cut polyester film (hereinafter also referred to as straight-cut PET film) made of PET and having tearability in the machine direction (MD) was prepared as the second stretched plastic film 50. Emblet (registered trademark) PC manufactured by Unitika Ltd. was used as the straight-cut PET film. The thickness of the straight-cut PET film was 12 μm.

[0371] Compared to typical stretched PET films, Emblett® PC has higher tear resistance in the machine direction (MD). The tensile strength of Emblett® PC in the machine direction (MD) is 200 MPa, and the tensile strength of Emblett® PC in the transverse direction (TD) is 180 MPa.

[0372] Furthermore, an unstretched polypropylene film ZK207 manufactured by Toray Advanced Film Co., Ltd. was prepared as the sealant layer 70. ZK207 contains the above-mentioned propylene-ethylene block copolymer. The thickness of the sealant layer 70 was 70 μm.

[0373] ZK207 has a high tensile modulus. Specifically, the tensile modulus of ZK207 in the machine direction (MD) is 780 MPa when the thickness is 50 μm and 680 MPa when the thickness is 60 μm. The tensile modulus of ZK207 in the transverse direction (TD) is 630 MPa when the thickness is 50 μm and 560 MPa when the thickness is 60 μm. Therefore, the product of the tensile modulus (MPa) and thickness (μm) of ZK207 in the machine direction is 39,000 when the thickness is 50 μm and 40,800 when the thickness is 60 μm. The product of the tensile modulus (MPa) and thickness (μm) of ZK207 in the transverse direction is 31,500 when the thickness is 50 μm and 33,600 when the thickness is 60 μm.

[0374] ZK207 also has low tensile elongation. Specifically, the tensile elongation of ZK207 in the machine direction (MD) is 790% when the thickness is 50 μm and 730% when the thickness is 60 μm. The tensile elongation of ZK207 in the transverse direction (TD) is 1020% when the thickness is 50 μm and 870% when the thickness is 60 μm. Therefore, the product of the tensile elongation (%) of ZK207 in the machine direction and the thickness (μm) is 39,500 when the thickness is 50 μm and 43,800 when the thickness is 60 μm. The product of the tensile elongation (%) of ZK207 in the transverse direction and the thickness (μm) is 51,000 when the thickness is 50 μm and 52,200 when the thickness is 60 μm.

[0375] Next, the first stretched plastic film 40, the second stretched plastic film 50, and the sealant layer 70 were laminated by dry lamination to produce the packaging material 30. A two-component polyurethane adhesive (main agent: RU-40, curing agent: H-4) manufactured by Rock Paint Co., Ltd. was used for the first adhesive layer 45 and the second adhesive layer 55. The main agent RU-40 is a polyester polyol. The thickness of the first adhesive layer 45 and the second adhesive layer 55 was 3.5 μm. The overall thickness of the packaging material 30 was 106 μm.

[0376] [Evaluation of puncture resistance] Next, the puncture strength of the packaging material 30 was measured in accordance with JIS Z1707 7.4. A Tensilon universal testing machine RTC-1310 manufactured by A&D was used as the measuring instrument. Specifically, as shown in FIG. 24 , a semicircular needle 90 with a diameter of 1.0 mm and a tip radius of 0.5 mm was pierced from the outer surface 30y side of a fixed test piece of the packaging material 30 at a speed of 50 mm / min (50 mm per minute), and the maximum stress until the needle 90 penetrated the packaging material 30 was measured. The maximum stress was measured for five or more test pieces, and the average value was taken as the puncture strength of the packaging material 30. The measurement was performed in an environment of 23°C and 50% relative humidity. The resulting puncture strength was 16.7 N.

[0377] [Evaluation of loop stiffness] The loop stiffness of the packaging material 30 was also measured in the machine direction and perpendicular direction. The measuring device used was a No. 581 Loop Stiffness Tester (registered trademark) LOOP STIFFNESS TESTER DA type manufactured by Toyo Seiki Seisakusho. The measurement was performed in an environment with a temperature of 23°C and a relative humidity of 50%. As a result, the loop stiffness of the packaging material 30 in the machine direction was 0.181 N, and the loop stiffness in the perpendicular direction was 0.153 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 30 in the machine direction by the thickness of the packaging material 30 was 0.00171 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 30 was 0.00144 N / μm.

[0378] [Evaluation of tearability] Next, two sheets of packaging material 30 bonded via the sealant layer 70 were cut out to a width V1 of 15 mm and a length V2 of 100 mm, as shown in FIG. 25, to prepare a test piece 100. The width V1 of the test piece 100 was parallel to the second direction D2 shown in FIG. 1. The length V2 of the test piece 100 was parallel to the machine direction (MD) when forming a film such as a stretched plastic film or a sealant film, and was also parallel to the first direction D1 shown in FIG. 1. In the test piece 100, two sheets of packaging material 30 were bonded over the entire area. Next, as shown in FIG. 25, a slit 28 was formed in the center of the test piece 100 in the width V1 direction. Next, the test piece 100 was torn by hand in the length V2 direction starting from the slit 28. The measurement was performed in an environment with a temperature of 23°C and a relative humidity of 50%. As a result, the test piece 100 could be torn in the direction of length V2 without stretching the sealant layer 70 of the packaging material 30 during the tearing process. In addition, the amount of positional deviation in the direction of width V1 between the two sheets of packaging material 30 at the torn portion was 5 mm or less.

[0379] [Evaluation of openability and heat resistance] Next, bags 10 were made using packaging material 30, and the openability and heat resistance of bags 10 were evaluated. Specifically, first, bag 10 shown in FIG. 15 was made using packaging material 30. Bag 10 had a height S1 of 145 mm and a width S2 of 150 mm. Furthermore, the height S3 of folded-back lower film 16, i.e., the height from the bottom end of bag 10 to folded-back portion 16f, was 43 mm. In the following description, bag 10 having a height S1 of 145 mm, a width S2 of 150 mm, and a height S3 of 43 mm is also referred to as an M-size bag 10. Next, 100 g of meat and oil-rich contents such as miso paste was filled into bag 10 through opening 11b of upper portion 11. At this time, the openability of opening 11b was evaluated. Specifically, it was confirmed whether the front film 14 and the back film 15 would each deform to have a curved shape that is convex on the outer surface side when a lateral force P was applied to the bag 10 using the zipper portion 105 as shown in Fig. 14. As a result, the front film 14 and the back film 15 were deformed to have a curved shape that is convex on the outer surface side.

[0380] After filling the bag 10 with the contents, the top 11 was heat-sealed to form the top seal portion 11a. The bag 10 containing the contents was then heated for two minutes using a 500W microwave oven to check whether or not damage occurred to the packaging material 30 constituting the bag 10. The test was carried out on 10 bags 10. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer from damage such as holes in the packaging material 30 or wrinkles in the packaging material 30.

[0381] (Example A2) A packaging material 30 was produced in the same manner as in Example A1, except that a straight-cut polyamide film (hereinafter also referred to as a straight-cut nylon film) made of nylon and having tearability in the machine direction (MD) was used as the second stretched plastic film 50. Bonyl CL manufactured by Kohjin Film & Chemicals Co., Ltd. was used as the straight-cut nylon film. The thickness of the straight-cut nylon film was 15 μm. The overall thickness of the packaging material 30 was 109 μm.

[0382] Bonyl CL has higher tear resistance in the machine direction (MD) than general oriented nylon films. The tensile strength of Bonyl CL in the machine direction (MD) is 269 MPa, and the tensile strength of Bonyl CL in the transverse direction (TD) is 255 MPa.

[0383] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 18.5 N, the loop stiffness in the machine direction was 0.178 N, and the loop stiffness in the perpendicular direction was 0.140 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00163 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00128 N / μm.

[0384] The tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 100 could be torn in the direction of length V2 without the sealant layer 70 of the packaging material 30 stretching during the tearing. Furthermore, the amount of positional deviation in the direction of width V1 between the two sheets of packaging material 30 at the torn portion was 5 mm or less.

[0385] Next, in the same manner as in Example A1, a bag 10 was produced using the packaging material 30, and the openability of the bag 10 when filling the contents into the bag 10 was evaluated. The size of the bag 10 was medium, as in Example A1. As a result, the front film 14 and the back film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, in the same manner as in Example A1, the heat resistance of the bag 10 containing the contents was evaluated. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but that no holes were formed in the packaging material 30.

[0386] (Example A3) A packaging material 30 was produced in the same manner as in Example 1, except that the straight-cut PET film used as the second stretched plastic film 50 in Example A1 was used as the first stretched plastic film 40, and the high-stiffness PET film used as the first stretched plastic film 40 in Example A1 was used as the second stretched plastic film 50. The overall thickness of the packaging material 30 was 106 μm.

[0387] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 16.5 N, the loop stiffness was 0.176 N, and the loop stiffness in the perpendicular direction was 0.152 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00166 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00143 N / μm.

[0388] Subsequently, the tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 100 could be torn in the direction of length V2 without the sealant layer 70 of the packaging material 30 stretching during the tearing.

[0389] Next, bags 10 were made using packaging material 30 in the same manner as in Example A1, and the openability of bags 10 when filling contents into bags 10 was evaluated. The size of bags 10 was medium, the same as in Example A1. As a result, the front surface film 14 and the back surface film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, the heat resistance of bags 10 containing contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer damage such as holes or wrinkles in packaging material 30.

[0390] (Example A4) A packaging material 30 was produced in the same manner as in Example A2, except that the straight-cut nylon film used as the second stretched plastic film 50 in Example A2 was used as the first stretched plastic film 40, and the high-stiffness PET film used as the first stretched plastic film 40 in Example A2 was used as the second stretched plastic film 50. The overall thickness of the packaging material 30 was 109 μm.

[0391] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 18.6 N, the loop stiffness in the machine direction was 0.175 N, and the loop stiffness in the perpendicular direction was 0.141 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00161 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00129 N / μm.

[0392] The tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant layer 70 of the packaging material 30 was not stretched during the tearing, and the test piece 100 could be torn in the direction of length V2.

[0393] Next, in the same manner as in Example A1, a bag 10 was produced using the packaging material 30, and the openability of the bag 10 when filling the contents into the bag 10 was evaluated. The size of the bag 10 was medium, as in Example A1. As a result, the front film 14 and the back film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, in the same manner as in Example A1, the heat resistance of the bag 10 containing the contents was evaluated. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but that no holes were formed in the packaging material 30.

[0394] (Example A5) A packaging material 30 was produced in the same manner as in Example A3, except that a 12 μm-thick biaxially oriented PET film provided with a transparent vapor deposition layer, a gas barrier coating film, and a printed layer was used as the first stretched plastic film 40. The biaxially oriented PET film used had the same tensile strength in the machine direction (MD) and the transverse direction (TD). The overall thickness of the packaging material 30 was 106 μm.

[0395] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 16.7 N, the loop stiffness in the machine direction was 0.176 N, and the loop stiffness in the perpendicular direction was 0.154 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00166 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00145 N / μm.

[0396] Next, bags 10 were made using packaging material 30 in the same manner as in Example A1, and the openability of bags 10 when filling contents into bags 10 was evaluated. The size of bags 10 was medium, the same as in Example A1. As a result, the front surface film 14 and the back surface film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, the heat resistance of bags 10 containing contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer damage such as holes or wrinkles in packaging material 30.

[0397] (Example A6) A packaging material 30 was produced in the same manner as in Example A1, except that a 12 μm-thick biaxially oriented PET film provided with a transparent vapor deposition layer and a gas barrier coating film was used as the second stretched plastic film 50. The biaxially oriented PET film used had approximately the same tensile strength in the machine direction (MD) and the transverse direction (TD). The overall thickness of the packaging material 30 was 106 μm.

[0398] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 16.9 N, the loop stiffness in the machine direction was 0.179 N, and the loop stiffness in the perpendicular direction was 0.157 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00169 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00148 N / μm.

[0399] Next, bags 10 were made using packaging material 30 in the same manner as in Example A1, and the openability of bags 10 when filling contents into bags 10 was evaluated. The size of bags 10 was medium, the same as in Example A1. As a result, the front surface film 14 and the back surface film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, the heat resistance of bags 10 containing contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer damage such as holes or wrinkles in packaging material 30.

[0400] (Comparative Example A1) The packaging material 30 was produced in the same manner as in Example A1, except that biaxially oriented PET films with a thickness of 12 μm were used as the first stretched plastic film 40 and the second stretched plastic film 50. The biaxially oriented PET film used had approximately the same tensile strength in the machine direction (MD) and the transverse direction (TD). The overall thickness of the packaging material 30 was 102 μm.

[0401] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 13.2 N, the loop stiffness in the machine direction was 0.151 N, and the loop stiffness in the perpendicular direction was 0.117 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00148 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00115 N / μm.

[0402] Subsequently, the tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant layer 70 of the packaging material 30 stretched during the tearing process, and the test piece 100 could not be torn in the direction of length V2.

[0403] Next, in the same manner as in Example A1, a bag 10 was produced using the packaging material 30, and the openability of the bag 10 when filling the bag 10 with contents was evaluated. The size of the bag 10 was medium, as in Example A1. As a result, in addition to multiple curved portions that were convex on the outer surface side, multiple curved portions that were convex on the inner surface side were formed on the front film 14 and the back film 15, and therefore, a sufficient opening width K could not be ensured. Furthermore, in the same manner as in Example A1, the heat resistance of the bag 10 containing the contents was evaluated. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but that no holes were formed in the packaging material 30.

[0404] ( Reference example A7) A packaging material 30 was produced in the same manner as in Example A1, except that a biaxially oriented PET film with a thickness of 12 μm was used as the second stretched plastic film 50, and a sealant film (thickness 50 μm) made of a mixed resin of low-density polyethylene and linear low-density polyethylene was used as the sealant layer 70. The biaxially oriented PET film used had approximately the same tensile strength in the machine direction (MD) and the transverse direction (TD). The overall thickness of the packaging material 30 was 86 μm.

[0405] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 16.5 N, the loop stiffness in the machine direction was 0.111 N, and the loop stiffness in the perpendicular direction was 0.121 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00129 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00141 N / μm.

[0406] Next, bags 10 were made using packaging material 30 in the same manner as in Example A1, and the openability of bags 10 when filling contents into bags 10 was evaluated. The size of bags 10 was medium, the same as in Example A1. As a result, the front surface film 14 and the back surface film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, the heat resistance of bags 10 containing contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer damage such as holes or wrinkles in packaging material 30.

[0407] ( Reference example A8) The packaging material 30 was produced in the same manner as in Example A7, except that the sealant layer 70 was an easy-peel sealant film (50 μm thick) formed by co-extrusion, including a first layer constituting the inner surface 30x of the packaging material 30 and a second layer located on the surface of the first layer facing the second stretched plastic film 50. The first layer was a 5 μm thick layer made of a mixed resin of high-density polyethylene and polypropylene. The second layer was a 45 μm thick layer made of high-density polyethylene. The overall thickness of the packaging material 30 was 86 μm.

[0408] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 16.2 N, the loop stiffness in the machine direction was 0.112 N, and the loop stiffness in the perpendicular direction was 0.115 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00130 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00134 N / μm.

[0409] Next, bags 10 were made using packaging material 30 in the same manner as in Example A1, and the openability of bags 10 when filling contents into bags 10 was evaluated. The size of bags 10 was medium, the same as in Example A1. As a result, the front surface film 14 and the back surface film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, the heat resistance of bags 10 containing contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer damage such as holes or wrinkles in packaging material 30.

[0411] ZK500 has a higher tensile elongation than general unstretched polypropylene films. Specifically, the tensile elongation of ZK500 in the machine direction (MD) is 1180% when the thickness is 50 μm and 1100% when the thickness is 60 μm. The tensile elongation of ZK500 in the transverse direction (TD) is 1240% when the thickness is 50 μm and 1150% when the thickness is 60 μm. Therefore, the product of the tensile elongation (%) of ZK500 in the machine direction and the thickness (μm) is 59,000 when the thickness is 50 μm and 66,000 when the thickness is 60 μm. The product of the tensile elongation (%) of ZK500 in the transverse direction and the thickness (μm) is 62,000 when the thickness is 50 μm and 69,000 when the thickness is 60 μm.

[0412] Furthermore, ZK500 has a lower tensile modulus than general unstretched polypropylene films. Specifically, the tensile modulus of ZK500 in the machine direction (MD) is 640 MPa when the thickness is 50 μm and 550 MPa when the thickness is 60 μm. The tensile modulus of ZK500 in the transverse direction (TD) is 480 MPa when the thickness is 50 μm and 400 MPa when the thickness is 60 μm. Therefore, the product of the tensile modulus (MPa) of ZK500 in the machine direction and the thickness (μm) is 32,000 when the thickness is 50 μm and 33,000 when the thickness is 60 μm. The product of the tensile modulus (MPa) of ZK500 in the transverse direction and the thickness (μm) is 24,000 when the thickness is 50 μm and 35,000 when the thickness is 60 μm.

[0413] Next, in the same manner as in Example A1, the puncture strength and loop stiffness in the machine direction and perpendicular direction of packaging material 30 were measured. As a result, the puncture strength was 16.8 N, the loop stiffness in the machine direction was 0.132 N, and the loop stiffness in the perpendicular direction was 0.110 N. In this case, the value obtained by dividing the loop stiffness in the machine direction of packaging material 30 by the thickness of packaging material 30 was 0.00138 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of packaging material 30 was 0.00115 N / μm.

[0414] Next, bags 10 were made using packaging material 30 in the same manner as in Example A1, and the openability of bags 10 when filling contents into bags 10 was evaluated. The size of bags 10 was medium, the same as in Example A1. As a result, the front surface film 14 and the back surface film 15 were deformed to have a curved shape that was convex on the outer surface side. Furthermore, the heat resistance of bags 10 containing contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that 10 out of 10 bags 10 did not suffer damage such as holes or wrinkles in packaging material 30.

[0415] The layer structures of the packaging materials 30 of Examples A1 to A6 and Comparative Example A1, as well as the evaluation results for puncture strength and loop stiffness, are shown together in Figure 26. The layer structures of the packaging materials 30 of Examples A1 to A6 and Comparative Example A1, as well as the evaluation results for tearability, heat resistance, and openability, are shown together in Figure 27. Reference example A7~ A8 The layer structure of the packaging material 30 and the evaluation results for puncture strength and loop stiffness are summarized in Figure 28. In Figures 26 to 28, the "Layer Structure" column lists the components of the packaging material 30 in order from the outermost layer to the top. In the "Heat Resistance" column, a rating of "great" was given if no holes or wrinkles were formed in the packaging material 30, a rating of "good" was given if wrinkles were formed in the packaging material 30 but no holes were formed, and a rating of "bad" was given if holes and wrinkles were formed in the packaging material 30. In the "Openability" column, a rating of "good" was given if the front and back films 14 and 15 were deformed to have a curved shape that was convex on the outer surface side, and a rating of "bad" was given if the front and back films 14 and 15 had multiple curved portions that were convex on the inner surface side in addition to multiple curved portions that were convex on the outer surface side.

[0416] Examples A1 to A6, reference example A7~A8As can be seen from the comparison between Examples A1, A3, and A5 and Comparative Example A1, by including a high stiffness polyester film in the packaging material 30, the puncture strength of the packaging material 30 could be increased to 14 N or more compared to when the packaging material 30 did not include a high stiffness polyester film. A6, reference example A7~A8 In Examples A1 and A2, the puncture strength of the packaging material 30 was 16 N or more. In Examples A2 and A4, in which the packaging material 30 contained a straight-cut polyamide film in addition to the high-stiffness polyester film, the puncture strength of the packaging material 30 was 18 N or more.

[0417] Furthermore, as can be seen from a comparison between Examples A1 to A6 and Comparative Example A1, by including a high-stiffness polyester film in the packaging material 30 and including a sealant layer 70 primarily composed of polypropylene, the loop stiffness of the packaging material 30 could be increased to 0.160 N or more, for example, 0.170 N or more or 0.180 N or more, in at least one direction, compared to a packaging material 30 that does not include a high-stiffness polyester film. Furthermore, the value obtained by dividing the loop stiffness of the packaging material 30 by the thickness of the packaging material 30 could be increased to 0.00150 N / μm or more, for example, 0.00160 N / μm or more, 0.00165 N / μm or more, or 0.00170 N / μm or more, in at least one direction. This improved the openability of the bag 10 incorporating the packaging material 30.

[0418] Furthermore, as can be seen from a comparison between Examples A1 to A4 and Comparative Example A1, by including a straight-cut film, such as a straight-cut polyester film or a straight-cut polyamide film, in the packaging material 30 that has tearability in the machine direction (MD), it was possible to prevent the sealant layer 70 from stretching when the packaging material 30 was torn. Regarding tearability, in Examples A3 and A4, the test piece 100 could be torn smoothly across the entire length V2, and therefore the evaluation result was "good." Furthermore, in Examples A1 and A2, the test piece 100 could be torn smoothly across the entire length V2, and the positional deviation in the width V1 direction between the two sheets of packaging material 30 constituting the test piece 100 was 5 mm or less, and therefore the evaluation result was "great." On the other hand, in comparison example A1, the sealant layer 70 of the packaging material 30 stretched during the process, and as a result, the test piece 100 could not be torn smoothly across the entire area in the direction of length V2, so the evaluation result was rated as "bad."

[0419] Next, examples and comparative examples relating to the case where the packaging material 210 has the barrier laminate film 205 as explained in the second embodiment will be described.

[0420] [Example B1] A high-stiffness PET film made of petroleum-derived PET and having a loop stiffness of 0.0017 N or more was prepared as the substrate 201. Specifically, XP-55 manufactured by Toray Industries, Inc. was used as the high-stiffness PET film. The thickness of the high-stiffness PET film was 16 μm. The measured loop stiffness of the high-stiffness PET film was 0.0021 N in both the machine direction and the perpendicular direction. The tensile modulus of the high-stiffness PET film in the machine direction was 4.8 GPa, and the tensile modulus of the high-stiffness polyester film in the perpendicular direction was 4.7 GPa. The tensile strength of the high-stiffness PET film in the machine direction was 292 MPa, and the tensile strength of the high-stiffness polyester film in the perpendicular direction was 257 MPa. The tensile elongation of the high-stiffness PET film in the machine direction was 107%, and the tensile elongation of the high-stiffness polyester film in the perpendicular direction was 102%. In this case, the tensile strength of the high-stiffness PET film in the machine direction divided by the tensile elongation was 2.73 [MPa / %], and the tensile strength of the high-stiffness PET film in the perpendicular direction divided by the tensile elongation was 2.52 [MPa / %]. The heat shrinkage of the high-stiffness PET film in both the machine direction and the perpendicular direction was 0.4%.

[0421] Next, the puncture strength of the high-stiffness PET film was measured in accordance with JIS Z1707 7.4. An A&D Tensilon universal material testing machine RTC-1310 was used as the measuring instrument. Specifically, a semicircular needle with a diameter of 1.0 mm and a tip radius of 0.5 mm was pierced into a fixed high-stiffness PET film specimen from the outer surface 30y side at a speed of 50 mm / min (50 mm per minute), and the maximum stress until the needle penetrated the high-stiffness PET film was measured. The maximum stress was measured for five or more specimens, and the average value was used as the puncture strength of the high-stiffness PET film. The measurement was performed under an environment of 23°C and 50% relative humidity. The resulting puncture strength was 10.2 N.

[0422] [Example B2] As the substrate 201, a PBT film containing multiple layers and produced by a casting method, as described in the first configuration of the second embodiment, was prepared. The PBT content in each layer was 80%, the number of layers was 1024, and the thickness of the PBT film was 15 μm. The tensile strength of the PBT film in the machine direction was 191 MPa, and the tensile strength of the PBT film in the perpendicular direction was 289 MPa. The tensile elongation of the PBT film in the machine direction was 195%, and the tensile elongation of the PBT film in the perpendicular direction was 100%. In this case, the tensile strength of the PBT film in the machine direction divided by the tensile elongation was 0.98 [MPa / %], and the tensile strength of the PBT film in the perpendicular direction divided by the tensile elongation was 2.89 [MPa / %]. The thermal shrinkage of the PBT film in both the machine direction and the perpendicular direction was 0.4%.

[0423] [Example C1] First, a vapor-deposited layer 202 was formed on a substrate 201, and a gas barrier coating film 203 was formed on the vapor-deposited layer 202 to produce a barrier laminate film 205. Subsequently, a packaging material 210 including the barrier laminate film 205 was produced.

[0424] First, the preparation of the barrier laminate film 205 will be described. First, a roll of the 16 μm-thick high-stiffness PET film used in Example B1 above was prepared as the substrate 201. Next, using the film-forming apparatus 260 shown in FIG. 23, the substrate 201 was subjected to oxygen plasma treatment, and then a vapor-deposited layer 202 containing aluminum oxide and having a thickness of 12 nm was formed on the oxygen-plasma-treated surface. The oxygen plasma treatment and film-forming process will be described in detail below.

[0425] In the oxygen plasma treatment, plasma was introduced from plasma supply nozzle 272 under the following conditions in plasma pretreatment chamber 262B onto the surface of substrate 201 on which vapor deposition layer 202 was to be formed, and plasma pretreatment was performed on substrate 201 being transported at a transport speed of 400 m / min. As a result, an oxygen plasma-treated surface was formed on the surface of substrate 201 on which vapor deposition layer 202 was to be formed. [Oxygen plasma pretreatment conditions] Plasma intensity: 200W·sec / m 2 Plasma formation gas ratio: oxygen / argon = 2 / 1 Voltage applied between pretreatment drum and plasma supply nozzle: 340V Vacuum level in pre-treatment compartment: 3.8Pa

[0426] In the film formation process, in the film formation chamber 262C into which the substrate 201 continuously transported from the plasma pretreatment chamber 262B was carried, aluminum was used as a target to form a vapor deposition layer 202 containing aluminum oxide having a thickness of 12 nm on the oxygen plasma-treated surface of the substrate 201 by vacuum deposition. A reactive resistance heating method was used as the heating means for the vacuum deposition method. The film formation conditions were as follows: [Aluminum oxide film formation conditions] ·Vacuum degree: 8.1×10 -2 Pa Conveying speed: 400m / min Oxygen gas supply: 20,000 sccm

[0427] Subsequently, a gas barrier coating film 203 was formed on the vapor deposition layer 202. Specifically, first, 385 g of water, 67 g of isopropyl alcohol, and 9.1 g of 0.5 N hydrochloric acid were mixed together to prepare a solution adjusted to pH 2.2. Then, 175 g of tetraethoxysilane as a metal alkoxide and 9.2 g of glycidoxypropyltrimethoxysilane as a silane coupling agent were added to the solution while cooling the solution to 10°C, thereby preparing solution A. Solution B was prepared by mixing 14.7 g of polyvinyl alcohol (water-soluble polymer) having a degree of polymerization of 2400 and a saponification degree of 99% or more, 324 g of water, and 17 g of isopropyl alcohol. Subsequently, the liquids A and B were mixed in a weight ratio of 6.5:3.5, and the solution thus obtained was used as a coating agent for a gas barrier coating film.

[0428] The gas barrier coating film coating agent prepared above was applied by spin coating onto the vapor deposition layer 202. The vapor deposition layer 202 was then heated in an oven at 180°C for 60 seconds to form a gas barrier coating film 203 having a thickness of approximately 400 nm on the vapor deposition layer 202. In this way, a barrier laminate film 205 having the substrate 201, the vapor deposition layer 202, and the gas barrier coating film 203 was obtained.

[0429] (Metamorphic rate) In a vacuum environment, the surface of the gas barrier coating film 203 of the barrier laminate film 205 was repeatedly soft-etched at a constant rate using a Cs (cesium) ion gun, while time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to measure ions derived from the gas barrier coating film 203, ions derived from the vapor-deposited layer 202, and ions derived from the substrate 201. For example, mass analysis was performed on C6 (mass number 72.00) ions derived from the resin film of the substrate 201 and Al2O4H (mass number 118.93) ions derived from the aluminum oxide vapor-deposited film of the vapor-deposited layer 202.

[0430] The time-of-flight secondary ion mass spectrometer used in the TOF-SIMS was a TOF.SIMS5 manufactured by ION TOF, Inc., and measurements were performed under the following measurement conditions, thereby obtaining the graph shown in FIG. (TOFSIMS measurement conditions) Primary ion type: Bi3++ (0.2 pA, 100 μs) ·Measurement area: 150×150μm 2 Etching gun type: Cs (1 keV, 60 nA) Etching area: 600 x 600 μm 2 Etching rate: 3sec / cycle Vacuuming time: 1 x 10 -6 >15 hours at < 100 mbar Measurements using a time-of-flight secondary ion mass spectrometer were carried out within 30 hours after the start of evacuation.

[0431] In the graph, the position where the strength of SiO2 (mass number 59.96), a constituent element of the gas barrier coating film 203, is half of the strength in the gas barrier coating film 203 is identified as the interface between the gas barrier coating film 203 and the vapor-deposited layer 202. In addition, the position where the strength of C6 (mass number 72.00), a constituent material of the substrate 201, is half of the strength in the substrate 201 is identified as the interface between the substrate 201 and the vapor-deposited layer 202. In addition, the distance in the thickness direction between the two interfaces is used as the thickness of the vapor-deposited layer 202.

[0432] Next, the peak representing the measured element bond Al2O4H (mass number 118.93) was determined, and the region from that peak to the interface was defined as the transition region. However, if the gas barrier coating film 203 is composed of a material with the same mass number as Al2O4H (mass number 118.93), it is necessary to separate the waveform of 118.93.

[0433] When the reaction product AlSiO4 and hydroxide Al2O4H are produced at the interface between the gas barrier coating film 203 and the vapor-deposited layer 202, they can be separated from the Al2O4H present at the interface between the substrate 201 and the vapor-deposited layer 202. In this way, the separation of the waveforms can be handled appropriately depending on the material of the gas barrier coating film 203.

[0434] In waveform separation, for example, the profile of mass number 118.93 obtained by TOF-SIMS may be subjected to nonlinear curve fitting using a Gaussian function, and overlapping peaks may be separated using the least squares Levenberg-Marquardt algorithm.

[0435] Two samples were prepared from the barrier laminate film 205 of Example C1, and the transformation rate of the vapor-deposited layer 202 for each of the two samples was calculated as (thickness W1 of the transition region / thickness of the vapor-deposited layer 202) × 100 (%). As a result, the transformation rate for the first sample was 36.2%, and the transformation rate for the second sample was 28.8%.

[0436] Next, the production of a packaging material 210 including a barrier laminate film 205 will be described. First, a 1 μm-thick printed layer 218 was formed on the gas barrier coating film 203 of the barrier laminate film 205. A film including the barrier laminate film 205 and a stretched plastic film 214 were bonded together by dry lamination via a first adhesive layer 213 consisting of an adhesive layer with a thickness of 3.5 μm. A biaxially stretched PET film (thickness: 12 μm) derived from fossil fuels was used as the stretched plastic film 214. Next, the stretched plastic film 214 and a film constituting the sealant layer 212 were bonded together by dry lamination via a second adhesive layer 215 consisting of an adhesive layer with a thickness of 3.5 μm. An unstretched polypropylene film (thickness: 60 μm) was used as the film for the sealant layer 212. An unstretched polypropylene film ZK207 manufactured by Toray Advanced Film Co., Ltd. was used as the unstretched polypropylene film. In this way, a packaging material 210 was produced having the layer structure shown in Fig. 18. The overall thickness of the packaging material 210 was 96 µm.

[0437] The layer structure of the packaging material 210 of this embodiment is expressed as follows: High PET16 / Transparent Vapor Deposition / Barrier / Print / Adhesion / PET12 / Adhesion / CPP60 "High PET" means high stiffness PET film. "Transparent vapor deposition" means a transparent vapor deposition layer containing aluminum oxide. "Barrier" means a gas barrier coating film. "Print" means a printed layer. "Adhesive" means an adhesive layer. "PET" means a stretched PET film. "CPP" means a non-stretched polypropylene film. Numbers indicate layer thickness (unit: μm).

[0438] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 16.9 N, the loop stiffness in the machine direction was 0.167 N, and the loop stiffness in the perpendicular direction was 0.142 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00174 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00148 N / μm.

[0439] Furthermore, as will be described below, the packaging material 210 of Example C1 was subjected to a retort treatment, and then the oxygen permeability and the water vapor permeability were measured.

[0440] (oxygen permeability) A four-sided sealed pouch was produced using the packaging material 210. Next, 100 mL of water was poured into the four-sided sealed pouch from the opening at the top, and then a seal was formed at the top to seal the four-sided sealed pouch. Next, the four-sided sealed pouch was subjected to a retort treatment at 121°C for 40 minutes at 2 atmospheres. Next, the packaging material 210 constituting one side of the four-sided sealed pouch after the retort treatment was cut out to prepare a sample for evaluating the oxygen permeability after the retort treatment.

[0441] Next, the sample after retort treatment was set so that the outer surface 210y side of the packaging material 210 was the oxygen supply side, and the oxygen permeability was measured in accordance with JIS K 7126 Method B under measurement conditions of 23°C and 100% RH atmosphere. The measuring device used was an oxygen permeability measuring device (manufactured by Modern Control (MOCON) [model name: OX-TRAN 2 / 21]). As a result, the oxygen permeability of the sample after retort treatment was 1.5 cc / m 2 / 24hr / atm was less than.

[0442] (Water vapor permeability) The water vapor permeability was measured using the same samples as those used in the measurement of oxygen permeability. Specifically, each sample was set so that the outer surface 210y of the packaging material 210 faced the sensor, and the water vapor permeability was measured in accordance with JIS K 7126 B method under measurement conditions of 37.8°C and 100% RH atmosphere. The measuring device used was a water vapor permeability measuring device (MOCON measuring device [model name: PERMATRAN 3 / 33]). As a result, the water vapor permeability of the sample after retort treatment was 2.0 g / m 2 / 24hr was less than.

[0443] The packaging material 210 of this embodiment can be used to form, for example, a pouch that is subjected to a retort process.

[0444] [Example C2] A barrier laminate film 205 was produced in the same manner as in Example C1. Subsequently, a packaging material 210 having the layer structure shown in Fig. 17 was produced in the same manner as in Example C1, except that a biaxially stretched nylon film (thickness: 15 µm) was used as the stretched plastic film 214. The overall thickness of the packaging material 210 was 99 µm.

[0445] The layer structure of the packaging material 210 of this embodiment is expressed as follows: High-quality PET16 / Transparent vapor deposition / Barrier / Printing / Adhesive / Nylon 15 / Adhesive / CPP60 "Nylon" means oriented nylon film.

[0446] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 18.1 N, the loop stiffness in the machine direction was 0.151 N, and the loop stiffness in the perpendicular direction was 0.134 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00153 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00135 N / μm.

[0447] Subsequently, in the same manner as in Example C1, the packaging material 210 of Example C2 was subjected to retort treatment, and then the oxygen permeability and the water vapor permeability were measured. As a result, the oxygen permeability of the sample after retort treatment was 1.5 cc / m 2 The water vapor permeability of the sample after retort treatment was 2.0 g / m 2 / 24hr was less than.

[0448] The packaging material 210 of this embodiment can be used to form, for example, a pouch that is subjected to a retort process.

[0449] [Example C3] A barrier laminate film 205 was produced in the same manner as in Example C1. A stretched plastic film 214 was prepared, and a printed layer 218 with a thickness of 1 μm was formed on the stretched plastic film 214. A stretched PET film (thickness: 12 μm) derived from fossil fuels was used as the stretched plastic film 214. The stretched plastic film 214 with the printed layer 218 formed thereon and the barrier laminate film 205 were then bonded together by dry lamination via a first adhesive layer 213 consisting of an adhesive layer with a thickness of 3.5 μm. The substrate 201 of the barrier laminate film 205 and the film constituting the sealant layer 212 were then bonded together by dry lamination via a second adhesive layer 215 consisting of an adhesive layer with a thickness of 3.5 μm. An unstretched polypropylene film (thickness: 60 μm) was used as the film for the sealant layer 212. The unstretched polypropylene film ZK207 manufactured by Toray Advanced Film Co., Ltd. was used as the unstretched polypropylene film. In this way, a packaging material 210 was produced having the layer structure shown in Fig. 19. The overall thickness of the packaging material 210 was 96 µm.

[0450] The layer structure of the packaging material 210 of this embodiment is expressed as follows: PET12 / printing / adhesion / barrier / transparent vapor deposition / high PET16 / adhesion / CPP60

[0451] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 17.2 N, the loop stiffness in the machine direction was 0.165 N, and the loop stiffness in the perpendicular direction was 0.141 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00172 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00147 N / μm.

[0452] Subsequently, in the same manner as in Example C1, the packaging material 210 of Example C2 was subjected to retort treatment, and then the oxygen permeability and the water vapor permeability were measured. As a result, the oxygen permeability of the sample after retort treatment was 1.5 cc / m 2 The water vapor permeability of the sample after retort treatment was 2.0 g / m 2 / 24hr was less than.

[0453] The packaging material 210 of this embodiment can be used to form, for example, a pouch that is subjected to a retort process.

[0454] [ Reference example C4] A barrier laminate film 205 was produced in the same manner as in Example C1. Subsequently, a packaging material 210 having the layer structure shown in Fig. 18 was produced in the same manner as in Example C1, except that a sealant layer (thickness: 50 µm) made of a mixed resin of low-density polyethylene and linear low-density polyethylene was used as the film for the sealant layer 212. The overall thickness of the packaging material 210 was 86 µm.

[0455] Book Reference example The layer structure of the packaging material 210 is expressed as follows: High PET16 / Transparent Vapor Deposition / Barrier / Print / Adhesive / PET12 / Adhesive / Blend PE50 "Blend PE" means a sealant layer made of a mixed resin of low density polyethylene and linear low density polyethylene.

[0456] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 16.5 N, the loop stiffness in the machine direction was 0.111 N, and the loop stiffness in the perpendicular direction was 0.121 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00129 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00141 N / μm.

[0457] In addition, as explained below, Reference example After the packaging material 210 of C4 was subjected to a boiling treatment, the oxygen permeability and the water vapor permeability were measured.

[0458] (oxygen permeability) A four-sided sealed pouch was produced using the packaging material 210. Next, 100 mL of water was poured into the four-sided sealed pouch from the opening at the top, and then a seal was formed at the top to seal the four-sided sealed pouch. Next, the four-sided sealed pouch was subjected to a boiling treatment at 95°C for 60 minutes. Next, the packaging material 210 constituting one side of the four-sided sealed pouch after the boiling treatment was cut out to prepare a sample for evaluating the oxygen permeability after the boiling treatment. Then, the oxygen permeability of the sample after the boiling treatment was measured in the same manner as in Example C1. As a result, the oxygen permeability was 1.5 cc / m 2 / 24hr / atm was less than.

[0459] (Water vapor permeability) Using the same sample as in the case of measuring the oxygen permeability, the water vapor permeability of the sample after boiling treatment was measured in the same manner as in Example C1. As a result, the water vapor permeability was 2.0 g / m 2 / 24hr was less than.

[0460] Book Reference exampleThe packaging material 210 can be used, for example, to form a pouch that is subjected to a boiling process.

[0461] [ Reference example C5] A barrier laminate film 205 was produced in the same manner as in Example C1. Subsequently, a packaging material 210 having the layer structure shown in Fig. 18 was produced in the same manner as in Example C2, except that a sealant layer (thickness: 50 µm) made of a mixed resin of low-density polyethylene and linear low-density polyethylene was used as the film for the sealant layer 212. The overall thickness of the packaging material 210 was 89 µm.

[0462] Book Reference example The layer structure of the packaging material 210 is expressed as follows: High PET16 / Transparent Vapor Deposition / Barrier / Printing / Adhesive / Nylon 15 / Adhesive / Blend PE50

[0463] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 17.4 N, the loop stiffness in the machine direction was 0.101 N, and the loop stiffness in the perpendicular direction was 0.109 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00113 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00122 N / μm.

[0464] Next, Reference example As in the case of C4, Reference example After the packaging material 210 of C5 was subjected to a boiling treatment, the oxygen permeability and the water vapor permeability were measured. As a result, the oxygen permeability of the sample after the boiling treatment was 1.5 cc / m 2 The water vapor permeability of the sample after boiling was 2.0 g / m 2 / 24hr was less than.

[0465] Book Reference exampleThe packaging material 210 can be used, for example, to form a pouch that is subjected to a boiling process.

[0466] [ Reference example C6] A barrier laminate film 205 was produced in the same manner as in Example C1. Subsequently, a packaging material 210 having the layer structure shown in Fig. 19 was produced in the same manner as in Example C3, except that a sealant layer (thickness: 50 µm) made of a mixed resin of low-density polyethylene and linear low-density polyethylene was used as the film for the sealant layer 212. The overall thickness of the packaging material 210 was 86 µm.

[0467] Book Reference example The layer structure of the packaging material 210 is expressed as follows: PET12 / printing / adhesion / barrier / transparent vapor deposition / high PET16 / adhesion / blend PE50

[0468] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 16.4 N, the loop stiffness in the machine direction was 0.114 N, and the loop stiffness in the perpendicular direction was 0.123 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00133 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00143 N / μm.

[0469] Next, Reference example As in the case of C4, Reference example After boiling the packaging material 210 of C6, the oxygen permeability and the water vapor permeability were measured. As a result, the oxygen permeability of the sample after boiling was 1.5 cc / m 2 The water vapor permeability of the sample after boiling was 2.0 g / m 2 / 24hr was less than.

[0470] Book Reference exampleThe packaging material 210 can be used, for example, to form a pouch that is subjected to a boiling process.

[0471] [ Reference example C7] A barrier laminate film 205 was produced in the same manner as in Example C1. Subsequently, a packaging material 210 having the layer configuration shown in FIG. 18 was produced in the same manner as in Example C1, except that the sealant layer 212 was an easy-peel sealant layer (50 μm thick) formed by co-extrusion and including the first layer 2121 and second layer 2122 shown in FIG. 21 . The first layer 2121 was a 5 μm thick layer made of a mixed resin of high-density polyethylene and polypropylene. The second layer 2122 was a 45 μm thick layer made of high-density polyethylene. The overall thickness of the packaging material 210 was 86 μm.

[0472] Book Reference example The layer structure of the packaging material 210 is expressed as follows: High PET16 / Transparent Vapor Deposition / Barrier / Printing / Adhesion / PET12 / Adhesion / Easy Peel 50 "Easy peel" refers to a sealant layer that includes a layer made of a mixed resin of polyethylene and polypropylene and has easy peel properties.

[0473] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 16.2 N, the loop stiffness in the machine direction was 0.112 N, and the loop stiffness in the perpendicular direction was 0.115 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00130 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00134 N / μm.

[0474] Next, in the same manner as in Example C1, a four-sided sealed pouch made using packaging material 210 was subjected to retort treatment, and then a sample cut out from the four-sided sealed pouch was used to measure the oxygen permeability and the water vapor permeability. As a result, the oxygen permeability of the sample after retort treatment was 1.5 cc / m 2 The water vapor permeability of the sample after retort treatment was 2.0 g / m 2 / 24hr was less than.

[0475] Book Reference example The packaging material 210 can be used to form, for example, a lid for a container with a lid that is to be subjected to a retort process. The container body of the container with a lid can be made of, for example, polypropylene.

[0476] [ Reference example C8] A barrier laminate film 205 was produced in the same manner as in Example C1. Reference example A packaging material 210 having the layer structure shown in Fig. 18 was produced in the same manner as in Example C2, except that a sealant layer (thickness: 50 µm) with easy peel properties was used as in the case of C7. The overall thickness of the packaging material 210 was 89 µm.

[0477] Book Reference example The layer structure of the packaging material 210 is expressed as follows: High PET16 / Transparent Vapor Deposition / Barrier / Printing / Adhesive / Nylon 15 / Adhesive / Easy Peel 50

[0478] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 17.0 N, the loop stiffness in the machine direction was 0.101 N, and the loop stiffness in the perpendicular direction was 0.102 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00113 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00115 N / μm.

[0479] Next, Reference example As in the case of C7, Reference example After the retort treatment was performed on the packaging material 210 of C8, the oxygen permeability and the water vapor permeability were measured. As a result, the oxygen permeability of the sample after the retort treatment was 1.5 cc / m 2 The water vapor permeability of the sample after retort treatment was 2.0 g / m 2 / 24hr was less than.

[0480] Book Reference example The packaging material 210 can be used to form, for example, a lid for a container with a lid that is to be subjected to a retort process. The container body of the container with a lid can be made of, for example, polypropylene.

[0481] [ Reference example C9] A barrier laminate film 205 was produced in the same manner as in Example C1. Reference example A packaging material 210 having the layer structure shown in Fig. 19 was produced in the same manner as in Example C3, except that a sealant layer (thickness: 50 µm) with easy peel properties was used as in C7. The overall thickness of the packaging material 210 was 86 µm.

[0482] Book Reference example The layer structure of the packaging material 210 is expressed as follows: PET12 / Printing / Adhesion / Barrier / Transparent Vapor Deposition / High PET16 / Adhesion / Easy Peel 50

[0483] Next, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength of the packaging material 210 was 16.3 N, the loop stiffness in the machine direction was 0.114 N, and the loop stiffness in the perpendicular direction was 0.119 N. In this case, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction by the thickness of the packaging material 210 was 0.00133 N / μm, and the value obtained by dividing the loop stiffness in the perpendicular direction by the thickness of the packaging material 210 was 0.00138 N / μm.

[0484] Next, Reference example As in the case of C7, Reference example After the retort treatment was performed on the packaging material 210 of C9, the oxygen permeability and the water vapor permeability were measured. As a result, the oxygen permeability of the sample after the retort treatment was 1.5 cc / m 2 The water vapor permeability of the sample after retort treatment was 2.0 g / m 2 / 24hr was less than.

[0485] Book Reference example The packaging material 210 can be used to form, for example, a lid for a container with a lid that is to be subjected to a retort process. The container body of the container with a lid can be made of, for example, polypropylene.

[0486] Examples C1 to C3 and Reference example The layer structures of the packaging materials 210 of Examples C4 to C9, and the evaluation results of the puncture strength and loop stiffness are shown in Figures 29 and 30, respectively. C3, reference example C4~ The layer structure of the packaging material 210 of C9, as well as the evaluation results of oxygen permeability and water vapor permeability, are shown in Figure 31. In the "Oxygen Permeability" column of Figure 31, "OK" indicates that the oxygen permeability of the sample after retort treatment was 1.5 cc / m 2 In the "Water vapor permeability" column of Figure 31, "OK" means that the water vapor permeability of the sample after retort treatment was 2.0 g / m 2This means that the time was less than 24 hours.

[0487] Examples C1 to C3, reference example C4~ As can be seen from C9, by using a high stiffness polyester film as the first stretched plastic film 40 or the second stretched plastic film 50, the A3, reference example A4~A8 As in the case of Example 1, the puncture strength of the packaging material 210 was increased to 14 N or more. Reference example In Examples C4, C6, C7, and C9, the puncture strength of the packaging material 210 was 16 N or more. In Examples C2 and C3, the packaging material 210 contained a biaxially oriented nylon film in addition to the high-stiffness polyester film. Reference example In C5 and C8, the puncture strength of the packaging material 30 was 17N or more.

[0488] Furthermore, as can be seen from Examples C1 to C3, by including a high-stiffness polyester film in packaging material 210 and including polypropylene as a main component in sealant layer 70, it was possible to increase the loop stiffness of packaging material 210 to 0.150 N or more in at least one direction. Furthermore, it was possible to increase the value obtained by dividing the loop stiffness of packaging material 210 by the thickness of packaging material 210 to 0.00150 N / μm or more in at least one direction. [Explanation of symbols]

[0489] 10 bags 11 Upper 12 Lower 12a Lower seal 13 Side 13a Side seal 14 Surface film 15 Back film 16 Lower film 17 Storage section 18 Contents 20 Steam release mechanism 20a Steam release seal 25 Easy-to-open means 26 notches 30 Packaging materials 31 Base material part 32 Printing layer 34 Deposited layer 36 Gas barrier coating film 40 First stretched plastic film 45 First adhesive layer 50 Secondary oriented plastic film 55 Second adhesive layer 70 Sealant Layer 80 test specimens 80A Flow direction test piece 80B Vertical Test Piece 80x inner surface 80y external surface 81 Loop section 82 Middle section 83 Fixed part 85 Loop Stiffness Meter 86 Chuck part 861 First chuck 862 Second chuck 87 Support member 88 load cells 201 Base material 202 Vapor deposited layer 203 Gas barrier coating film 205 Barrier laminated film 210 Packaging materials 212 Sealant Layer 2121 1st layer 2122 2nd layer 213 1st adhesive layer 214 Stretched plastic film 218 Printing layer

Claims

1. A packaging material comprising, in order from the outer surface side to the inner surface side, at least a first biaxially oriented plastic film, a second biaxially oriented plastic film, and a sealant layer, The biaxially oriented plastic films contained in the packaging material are only the first biaxially oriented plastic film and the second biaxially oriented plastic film, The sealant layer contains polypropylene as a main component, A packaging material, wherein the value obtained by dividing the loop stiffness in one direction of the packaging material by the thickness of the packaging material is 0.00150 [N / μm] or more.

2. One of the first biaxially oriented plastic film or the second biaxially oriented plastic film is a high-stiffness polyester film, and the other of the first biaxially oriented plastic film or the second biaxially oriented plastic film contains polyester or polyamide as a main component; The packaging material according to claim 1 , wherein the high-stiffness polyester film has a loop stiffness of 0.0017 N or more in one direction and contains polyester as a main component.

3. One of the first biaxially oriented plastic film or the second biaxially oriented plastic film is a high-stiffness polyester film, and the other of the first biaxially oriented plastic film or the second biaxially oriented plastic film contains polyester or polyamide as a main component; 3. The packaging material according to claim 1, wherein the tensile strength of the high stiffness polyester film divided by the tensile elongation is 2.0 MPa / % or more in at least one direction.

4. The packaging material according to claim 2 or 3, wherein the high-stiffness polyester film contains polyethylene terephthalate as a main component.

5. The packaging material according to claim 1 , wherein the packaging material has a puncture strength of 14 N or more.

6. 5. The packaging material according to claim 2, wherein the high stiffness polyester film has a tensile strength in one direction of 250 MPa or more.

7. A packaging material described in any one of claims 1 to 6, wherein either the first biaxially oriented plastic film or the second biaxially oriented plastic film is a straight-cut film having a tensile strength in one direction greater than the tensile strength in a direction perpendicular to the one direction.

8. 8. The packaging material of claim 7, wherein the tensile strength of the straight-cut film in one direction is at least 1.05 times the tensile strength of the straight-cut film in a direction perpendicular to the one direction.

9. The packaging material according to claim 1 , further comprising a printed layer.

10. The packaging material according to claim 3 , wherein the sealant layer is made of a single layer film containing a propylene-ethylene block copolymer.

11. The packaging material according to any one of claims 1 to 10, further comprising a vapor deposition layer located on either the first biaxially oriented plastic film or the second biaxially oriented plastic film, and a gas barrier coating film located on the vapor deposition layer.

12. A retort pouch comprising the packaging material according to any one of claims 1 to 11.

13. A microwave pouch having a storage section, A packaging material according to any one of claims 1 to 11; a seal portion joining the inner surfaces of the packaging material together, the seal portion including a steam release seal portion that peels off due to an increase in pressure in the containing portion.

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