Packaging material (および) is a multilayered material used for packaging.

Abstract

The present invention provides a laminated material for packaging, packaging materials, and packaging bodies that possess barrier properties and retort resistance, and that can suppress the occurrence of tearing and pinholes when forming packaging materials. [Solution] The packaging laminate 1 has a bottom wall and a bulging portion consisting of a side wall integrally provided to project in one direction from the periphery of the bottom wall, and is a packaging laminate 1 for forming packaging that will be exposed to a high-temperature atmosphere for sterilization treatment. The packaging laminate 1 consists of a protective resin layer 11, a barrier layer 12, and a sealant layer 17 laminated in this order from one side. A molding auxiliary resin layer 15 is provided between the barrier layer 12 and the sealant layer 17.

Description

Technical Field

[0001] The present invention relates to a laminate for packaging materials used for packaging materials exposed to a high-temperature atmosphere for sterilization treatment such as retort treatment, a packaging material using the laminate for packaging materials, and a package using the packaging material.

[0002] In this specification and the claims, the term "aluminum" shall include aluminum alloys in addition to pure aluminum.

Background Art

[0003] Packaging materials that form packages in which foods, pharmaceuticals, etc. are packaged generally have a barrier property that blocks the entry of water vapor, oxygen, and other gases that can deteriorate the contents, for the purpose of suppressing deterioration and spoilage of the contents and maintaining their functions and properties, and a laminate for packaging materials having retort resistance for the purpose of preventing delamination when exposed to a high-temperature atmosphere for sterilization treatment such as retort treatment.

[0004] As a laminate for packaging materials having barrier properties and retort resistance, a surface layer, a base material layer, an aluminum layer, an adhesive layer, and an easy peel layer are laminated in this order, and the adhesive layer has a layer mainly composed of maleic anhydride graft polymerized polypropylene, and the weight average molecular weight of maleic anhydride graft polymerized polypropylene is 300,000 to 350,000. A laminated lid material has been proposed (see Patent Document 1).

[0005] The laminated lid material described in Patent Document 1 obtains the above-described retort resistance by the function of the adhesive layer.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] However, when a packaging material having a bulging portion consisting of a bottom wall and a side wall integrally provided to project in one direction from the periphery of the bottom wall is formed using the laminated lid material described in Patent Document 1, for example by a stretching process, there is a risk of tearing or pinholes occurring.

[0008] In view of the above circumstances, this invention aims to provide a laminated material for packaging, a packaging material, and a packaging body that have barrier properties and retort resistance, and that can suppress the occurrence of tearing and pinholes even when a packaging material having a bulging portion consisting of a bottom wall and a side wall integrally provided so as to protrude in one direction from the periphery of the bottom wall is formed by stretching or other methods. [Means for solving the problem]

[0009] To achieve the above objective, this invention comprises the following embodiments.

[0010] 1) A laminated material for packaging that has a bottom wall and a bulge portion consisting of a side wall integrally provided to project in one direction from the periphery of the bottom wall, and which forms packaging material that is exposed to a high-temperature atmosphere for sterilization treatment, A laminate for packaging materials, comprising a laminate in which a protective resin layer, a barrier layer, and a sealant layer are laminated in this order from one side, with a molding aid resin layer provided between the barrier layer and the protective resin layer or sealant layer.

[0011] 2) The packaging laminate according to 1) above, wherein a molding auxiliary resin layer is provided between the barrier layer and the sealant layer.

[0012] 3) The packaging laminate according to 2) above, wherein adhesive layers are provided between the protective resin layer and the barrier layer, between the barrier layer and the molding auxiliary resin layer, and between the molding auxiliary resin layer and the sealant layer.

[0013] 4) The packaging laminate according to 1) above, wherein the molding auxiliary resin layer is made of a biaxially oriented nylon film.

[0014] 5) The packaging laminate according to 1) above, wherein the molding auxiliary resin layer is made of a biaxially oriented polyester film.

[0015] 6) A packaging material that is formed using a laminated material for packaging materials described in any of 1) to 5) above, and has a bulge consisting of a bottom wall and a side wall integrally provided on the periphery of the bottom wall so as to project in one direction, and an opening in the bulge is formed surrounded by the protruding end of the side wall, wherein the protective resin layer of the laminated material for packaging materials is located on the outer surface side of the bottom wall and the side wall.

[0016] 7) The packaging material according to 6) above, wherein the bulge height of the bulging portion is 20-50% of the equivalent circular diameter of the opening.

[0017] 8) A packaging material formed using a laminated material for packaging materials described in any of 1) to 5) above, and having a bulge consisting of a bottom wall and a side wall integrally provided on the periphery of the bottom wall so as to project in one direction, wherein the opening of the bulge is formed surrounded by the protruding end of the side wall, and the sealant layer of the laminated material for packaging materials is located on the outer surface side of the bottom wall and the side wall.

[0018] 9) The packaging material as described in 8) above, wherein the bulge height of the bulging portion is 20-50% of the circular diameter of the opening.

[0019] 10) A package in which an outward-facing flange is provided on the periphery of the opening of the bulge of the packaging material described in 6) above, and the surface of the flange opposite to the surface facing the bottom wall of the bulge is covered with a sealant layer; an outward-facing flange is provided on the periphery of the opening of the bulge of the packaging material described in 8) above, and the surface of the flange facing the bottom wall of the bulge is covered with a sealant layer; the height of the bulge of the packaging material described in 8) above is lower than the height of the internal space of the bulge of the packaging material described in 6) above; the bulge of the packaging material described in 8) above is inserted into the space inside the bulge of the packaging material described in 6) above to form a storage space between the two packaging materials; and with contents placed in the storage space, the flanges of both packaging materials are heat-sealed together using the sealant layers of both packaging materials. [Effects of the Invention]

[0020] The laminated packaging materials described in 1) to 5) above possess barrier properties due to the function of the barrier layer, and also have retort resistance due to the heat resistance and water resistance of the materials forming each layer. Furthermore, due to the function of the molding auxiliary resin layer, even when packaging materials having a bulge consisting of a bottom wall and a side wall integrally provided to protrude in one direction from the periphery of the bottom wall are molded by, for example, cold stretching, the occurrence of cracking and fracture of the material is suppressed.

[0021] Furthermore, with respect to the laminated packaging materials described in 1) to 5) above, it is possible to suppress the occurrence of tears and pinholes when molding any of the packaging materials, such as the packaging material described in 6) above, which has a bulge consisting of a bottom wall and a side wall integrally provided so as to protrude in one direction from the periphery of the bottom wall, with an opening in the bulge being formed surrounded by the protruding ends of the side wall, and the protective resin layer of the laminated packaging material located on the outer surface side of the bottom wall and side wall, or the packaging material described in 8) above, which has a bulge consisting of a bottom wall and a side wall integrally provided so as to protrude in one direction from the periphery of the bottom wall, with an opening in the bulge being formed surrounded by the protruding ends of the side wall, and the sealant layer of the laminated packaging material located on the outer surface side of the bottom wall and side wall.

[0022] According to the laminate for packaging material of 2) above, the moldability when molding the packaging materials of 6) and 8) above becomes even better.

[0023] According to the packaging materials of 6) to 9) above, since they are molded using the laminate for packaging material of 1) to 5) above, they have barrier properties and retort resistance. Also, due to the function of the molding auxiliary resin layer, it becomes possible to suppress the occurrence of breakage and pinholes during molding, for example, by overhanging processing in the cold state.

[0024] According to the package of 10) above, it becomes possible to subject the contents to a retort treatment while containing and holding the contents in the accommodation space formed between the inner surface of the bulging portion of the packaging material described in 6) and the outer surface of the bulging portion of the packaging material described in 8).

Brief Description of the Drawings

[0025] [Figure 1] It is a partially enlarged vertical cross-sectional view showing an embodiment of the laminate for packaging material according to this invention. [Figure 2] It shows a cup-shaped packaging material molded using the laminate for packaging material of FIG. 1, (a) is a vertical cross-sectional view of the first packaging material, and (b) is a vertical cross-sectional view of the second packaging material. [Figure 3] It is a vertical cross-sectional view showing a package made of the packaging material shown in FIG. 2. [Figure 4] (a) is a vertical cross-sectional view showing a package using a modified example of the first packaging material and a modified example of the second packaging material, (b) is a vertical cross-sectional view showing the problem when the packaging material curls to the sealant layer side in the package shown in (a), and (c) is a vertical cross-sectional view showing the problem when the packaging material curls to the protective resin layer side in the package shown in (a). [Figure 5] It is a plan view showing a test piece used in Evaluation Tests 4 to 6.

Modes for Carrying Out the Invention

[0026] Hereinafter, embodiments of this invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited by the embodiments shown in the drawings.

[0027] Figure 1 shows a laminated material for packaging according to this invention. Figures 2(a) and 2(b) show cup-shaped packaging materials formed using the laminated material for packaging shown in Figure 1, and Figure 3 shows a package made from the packaging material shown in Figure 2.

[0028] Note that in each diagram, the thickness and ratio of each layer in the laminate forming the packaging material differ from the actual values ​​for the sake of clarity.

[0029] In Figure 1, the laminated material (1) for packaging according to this invention has a protective resin layer (11), an adhesive layer (12), a barrier layer (13), an adhesive layer (14), a molding aid resin layer (15), an adhesive layer (16), and a sealant layer (17) laminated in this order from one side.

[0030] The protective resin layer (11) is preferably formed as a single-layer film made of polyester or a multi-layer film formed by laminating multiple such single-layer films, with a thickness of 5 to 40 μm, and more preferably with a thickness of 9 to 25 μm. Examples of polyester include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT).

[0031] The barrier layer (13) is a layer that protects the contents of a package having a packaging material (10) formed from a packaging laminate (1) from gas, water vapor, light, etc. It consists of a metal foil made of a metal such as aluminum, copper, iron (stainless steel), titanium, or nickel, but considering processability, barrier function, and cost, it is preferable to use aluminum foil. As for the aluminum foil, it is preferable to use foil with a thickness of 15 to 60 μm made of soft aluminum (O material) of the 1000 series or 8000 series as specified in JIS H4160:1994. If the thickness of the barrier layer (13) is too large, the moldability of the packaging material (10), which will be described later, may be impaired, and if it is too small, defects such as pinholes are likely to occur in the barrier layer (13).

[0032] The aluminum foil forming the barrier layer (13) is preferably made of an Al-Fe alloy containing 0.7 to 1.7 mass% of Fe, specifically A8021H-O material, A8079H-O material, etc., as specified in JIS H4160:1994. The Si content as an impurity in the Al-Fe alloy containing 0.7 to 1.7 mass% of Fe is preferably 0.1 mass% or less. When aluminum foil made of an Al-Fe alloy containing 0.7 to 1.7 mass% of Fe is used as the barrier layer (13), the processability of the packaging material (10) during cold stretching is improved.

[0033] Furthermore, if the barrier layer (13) is made of aluminum foil, it is preferable that both sides of the barrier layer (13) are subjected to a surface treatment such as chemical conversion treatment. By applying chemical conversion treatment to both sides of the barrier layer (13), it is possible to make the adhesion between the barrier layer (13) and the adhesive layer (5) after cold stretching work stronger, ensuring sufficient moldability, and also preventing delamination between the barrier layer (13) and the protective resin layer (11) and the molding auxiliary resin layer (15) when the packaging material, which is made from the packaging laminate (1) and contains contents and is sealed, is subjected to heat sterilization treatment.

[0034] The molding auxiliary resin layer (15) is a layer that improves the moldability of the packaging laminate (1) and suppresses the occurrence of tears and pinholes when a cup-shaped packaging material having a bulge consisting of a bottom wall and side walls integrally provided to protrude in one direction from the periphery of the bottom wall is formed by, for example, cold stretching of the packaging laminate (1). The molding auxiliary resin layer (15) is preferably formed of a biaxially oriented nylon film or a biaxially oriented polyester film such as PET, PEN, or PBT.

[0035] The thickness of the molding auxiliary resin layer (15) is preferably 7 to 40 μm. If the thickness of the molding auxiliary resin layer (15) is less than 7 μm, the molding auxiliary effect will not be obtained, and if it exceeds 40 μm, warping after molding may interfere with the sealing process.

[0036] The sealant layer (17) is made of a packaging material formed from a packaging laminate (1), and considering the heat resistance when the sealed package containing the contents is subjected to heat and pressure sterilization, it is preferable to use, for example, an unoriented polypropylene film. Alternatively, an unoriented film made of high-density polyethylene, an unoriented film made of linear low-density polyethylene, or an unoriented film made of a mixture of polypropylene, high-density polyethylene, and linear low-density polyethylene can also be used. The thickness of the sealant layer (17) is preferably 20 to 60 μm. If the thickness of the sealant layer (17) is less than 20 μm, sealing defects may occur due to thinning during sealing, and if it exceeds 60 μm, the barrier performance may decrease and the amount of heat required for sealing may increase, potentially lengthening the cycle time.

[0037] As the adhesive forming each adhesive layer (12), (14), and (16), it is preferable to use a heat-resistant adhesive, such as a polyurethane resin adhesive, and in particular, it is preferable to use a two-component curing polyether-urethane resin adhesive and / or a two-component curing polyester-urethane resin adhesive. Examples of curing agents include polyfunctional isocyanates, polyfunctional epoxy compounds, polyfunctional oxazoline compounds, and ketimine compounds. The thickness of the adhesive layers (12), (14), and (16) is preferably 1 to 10 μm, and more preferably 3 to 6 μm. If the thickness of the adhesive layers (12), (14), and (16) is too thick, defects are more likely to occur during adhesive application, and if it is too thin, delamination is more likely to occur due to a decrease in adhesive strength.

[0038] Figure 2 shows a specific example of packaging material consisting of a laminate for packaging materials (1).

[0039] The first packaging material (2) shown in Figure 2(a) has a bulge (20) consisting of a bottom wall (21) and a side wall (22) integrally provided on the periphery of the bottom wall (21) so as to project in one direction. An opening (23) of the bulge (20) is formed surrounded by the protruding ends of the side wall (22), and an outward-facing flange (24) is integrally provided on the opening (23) side end of the side wall (22) of the bulge (20). The protective resin layer (11) of the packaging laminate (1) is located on the outer surfaces of the bottom wall (21) and side wall (22) of the bulge (20) of the first packaging material (2), and on the surface of the flange (24) facing the bottom wall (21) side (the upper surface in Figure 2(a)). In the case of the first packaging material (2) shown in Figure 2(a), the internal space of the bulge (20) becomes a storage section (25) for containing the contents. The first packaging material (2) is formed by applying a protrusion process to the packaging laminate (1) so that it extends outwards toward the protective resin layer (11). In this embodiment, both the inner and outer surfaces of the bottom wall (21) are partially spherical, and the side walls (22) are inclined to spread outwards downwards from the periphery of the bottom wall (21) (to both the left and right sides in Figure 2). However, the embodiment is not limited to this, and for example, the bottom wall and side walls may be smoothly connected so that both the inner and outer surfaces are partially spherical, or a projection may be provided on a part of the bottom wall that protrudes inwards or outwards toward the housing (25).

[0040] The height (H) of the bulge (20) of the first packaging material (2) is preferably 20-50% of the equivalent diameter of the opening (23), and more preferably 30-40%. The lower limit of the ratio of the height (H) of the bulge (20) to the equivalent diameter is the ratio required by the type of contents contained in the packaging body comprising the first packaging material (2) and the second packaging material (3), and is not particularly limited. The upper limit of the ratio of the height (H) of the bulge (20) to the equivalent diameter is determined considering the moldability when forming the laminated material (1) for packaging, and if the upper limit of this ratio is too large, there is a risk that pinholes, tears, etc. may occur in the bottom wall (21) or side wall (22) of the bulge (20) of the first packaging material (2). In particular, when the molding auxiliary resin layer (15) of the packaging laminate (1) is made of a biaxially oriented nylon film, the upper limit of the ratio of the height (H) of the bulge (20) of the first packaging material (2) to the equivalent circle diameter is preferably 50%, and more preferably 35%. Also, when the molding auxiliary resin layer (15) of the packaging laminate (1) is made of a biaxially oriented PET film, the upper limit of the ratio of the height (H) of the bulge (20) of the first packaging material (2) to the equivalent circle diameter is preferably 40%, and more preferably 25%. In either case, if the upper limit is exceeded during molding, there is a concern that cracks or pinholes may occur due to material vibration, etc.

[0041] The second packaging material (3) shown in Figure 2(b) has a bulge (30) consisting of a bottom wall (31) and a side wall (32) integrally provided on the periphery of the bottom wall (31) so as to project in one direction. An opening (33) of the bulge (30) is formed surrounded by the protruding ends of the side wall (32), and an outward-facing flange (34) is integrally provided on the opening (33) side end of the side wall of the bulge (30). The sealant layer (17) of the packaging laminate (1) is located on the outer surfaces of the bottom wall (31) and side wall (32) of the bulge (30) of the second packaging material (3), and on the surface of the flange (34) facing the bottom wall (31) side (the upper surface in Figure 2(b)). The ratio of the height (h) of the bulge (30) of the second packaging material (3) to the height (H) of the bulge (20) of the first packaging material (2) is appropriately selected within the range of 30 to 80% depending on the type of contents. The second packaging material (3) is formed by applying a bulge processing to the packaging laminate (1) so that it protrudes toward the sealant layer (17). In this embodiment, both the inner and outer surfaces of the bottom wall (31) are partially spherical, and the side walls (32) are inclined to spread outward downward from the periphery of the bottom wall (31) (both left and right sides in Figure 2), but it is not limited to this, and for example, the bottom wall and side walls may be smoothly connected so that both the inner and outer surfaces are partially spherical, or a protrusion may be provided on a part of the bottom wall that protrudes inward or outward toward the bulge (30).

[0042] The height (h) of the bulge (30) of the second packaging material (3) is preferably 20-50% of the equivalent circular diameter of the opening, and more preferably 30-40%. The lower limit of the ratio of the height (h) of the bulge (30) to the equivalent circular diameter is not particularly limited. The upper limit of the ratio of the height (h) of the bulge (30) of the second packaging material (3) to the equivalent circular diameter is determined considering the moldability when forming the laminated material (1) for packaging, and considering that a storage space of the necessary size for accommodating the contents can be secured in the packaging body equipped with both packaging materials (2) and (3). If the upper limit of this ratio is too large, pinholes, tears, etc. may occur in the bottom wall (31) or side wall (32) of the bulge (30) of the formed second packaging material (3), or it may not be possible to secure the necessary storage space in the packaging body. In particular, when the molding auxiliary resin layer (15) of the packaging laminate (1) is made of a biaxially oriented nylon film, the upper limit of the ratio of the height (h) of the bulge portion of the second packaging material (3) to the equivalent diameter of the circle is preferably 50%, and more preferably 35%. Also, when the molding auxiliary resin layer (15) of the packaging laminate (1) is made of a biaxially oriented PET film, the upper limit of the ratio of the height (h) of the bulge portion (30) of the second packaging material (3) to the equivalent diameter of the circle is preferably 40%, and more preferably 25%. In either case, if the upper limit is exceeded during molding, there is a concern that cracks or pinholes may occur due to material vibration.

[0043] Figure 3 shows a package using the first packaging material (2) and the second packaging material (3).

[0044] In Figure 3, the packaging (4) is formed when the bulge (30) of the second packaging material (3) is inserted through the opening (23) into the internal space (25) of the bulge (20) of the first packaging material (2), thereby creating a storage space (41) between the two packaging materials (2) and (3). With contents (not shown) placed in this storage space (41), the flanges (24) and (34) of the two packaging materials (2) and (3) are heat-sealed together using the sealant layer (17) of both packaging materials (2) and (3), with the second packaging material (3) used as the lid.

[0045] The containment space (41) can house optical lenses such as hydrophilic soft contact lenses, intracrystalline lenses, and small, high-precision lenses for vision correction, as well as fragile sheet-like materials such as sheet-like cell cultures.

[0046] Figure 4 shows a package using a modified version of the first packaging material (2) and a modified version of the second packaging material (3).

[0047] In Figure 4(a), the flanges (24) and (34) of the first packaging material (200) and the second packaging material (300) are provided with outwardly protruding opening tabs (201) and (301) respectively on a portion of their entire circumference. In the package (400) consisting of both packaging materials (200) and (300), the opening tabs (201) and (301) are not heat-sealed, and the contents are removed by separating the first packaging material (200) and the second packaging material (300) using the opening tabs (201) and (301). The other components of both packaging materials (200) and (300) and the package (400) are the same as those of both packaging materials (2) and (3) and the package (4) shown in Figure 3, and the same parts are denoted by the same reference numerals.

[0048] However, if both opening tabs (201) and (301) curl toward the sealant layer (17) of the packaging laminate (1), as shown in Figure 4(b), the tips of both opening tabs (201) and (301) will press against each other, causing the parts excluding the tips to separate and creating a gap. In this case, it may become difficult to separate the two packaging materials (200) and (300) by pinching both opening tabs (201) and (301). Also, if both opening tabs (201) and (301) curl toward the protective resin layer (11) of the packaging laminate (1), as shown in Figure 4(c), both opening tabs (201) and (301) will curl in a fairly large arc toward the tips, creating a relatively large gap between the two opening tabs (201) and (301), which may result in an unsightly appearance. Furthermore, in both cases shown in Figure 4(b) and Figure 4(c), there is a risk of misalignment when the packages are stacked. In Figures 4(a) to 4(c), the boundary between the heat-sealed flanges (24) and (34) and the unheat-sealed opening tabs (201) and (301) is indicated by the dashed line X.

[0049] Next, examples and comparative examples of the present invention will be described.

[0050] [Example 1] As the metal foil forming the barrier layer (13), a 30 μm thick aluminum foil made of A8021H-O material as specified in JIS H4160:1994 was prepared. As the heat-sealable resin forming the sealant layer (17), a 30 μm thick unoriented polypropylene film was prepared. As the film forming the protective resin layer (11), a 12 μm thick biaxially oriented PET film was prepared. In addition, a 12 μm thick biaxially oriented PET film was prepared as the film forming the molding auxiliary resin layer (15).

[0051] Then, a chemical treatment solution consisting of phosphoric acid, polyacrylic acid, chromium(III) salt compound, water, and ethanol is applied to both sides of the aluminum foil, with a chromium deposition amount of 10 mg / m² per side. 2 After applying the coating and drying it at 150°C for 30 seconds as a base treatment, a polyurethane resin adhesive is applied at a rate of 3.5 g / m².2 The adhesive was applied in such a manner, and a biaxially oriented PET film, which would serve as a protective resin layer (11), was bonded to one side of the aluminum foil using the adhesive, while a biaxially oriented PET film, which would serve as a molding auxiliary resin layer (15), was bonded to the other side of the aluminum foil. Furthermore, a polyurethane resin-based adhesive was applied to the other side of the biaxially oriented PET film that would serve as the molding auxiliary resin layer (15) at a rate of 3.5 g / m². 2 The adhesive was applied in this manner, and an unoriented polypropylene film, which would form the sealant layer (17), was bonded to it using the adhesive. In this way, a laminated material for packaging was created.

[0052] [Example 2] A laminated material for packaging was prepared in the same manner as in Example 1, except that a biaxially oriented nylon film with a thickness of 15 μm was used as the film for forming the molding auxiliary resin layer (15).

[0053] [Comparative Example 1] A laminated material for packaging was prepared in the same manner as in Example 1, except that it did not include a molding auxiliary resin layer (15).

[0054] [Evaluation Test 1] Five sets of test specimens made from the laminated packaging materials of Examples 1-2 and Comparative Example 1 were prepared, and a total of nine bulges were formed on each test specimen by cold stretching by pressing from the sealant layer (17) side. The bottom wall of the bulge was spherical with a radius of curvature of 20 mm, and the side wall protruded linearly downward and diagonally outward from the periphery of the surrounding wall, and the opening of the bulge was circular with a diameter of 15.5 mm. In each test specimen, the bulges were arranged in two parallel linear rows, with four bulges in one row and five in the other row.

[0055] For the test specimens made from the laminated packaging material of Examples 1 and 2 and Comparative Example 1, the height of the bulging portion was set to 4.5 mm, 5.0 mm, and 5.5 mm.

[0056] Then, each test specimen was visually inspected for the presence or absence of cracks and pinholes in the bulging area.

[0057] [Evaluation Test 2] Five sets of test specimens made from the laminated packaging materials of Examples 1-2 and Comparative Example 1 were prepared, and a total of nine bulges were formed on each test specimen by cold stretching by pressing from the protective resin layer (11) side. The bottom wall of the bulge was spherical with a radius of curvature of 20 mm, and the side wall protruded linearly downward and diagonally outward from the periphery of the surrounding wall, and the opening of the bulge was circular with a diameter of 15.5 mm. In each test specimen, the bulges were arranged in two parallel linear rows, with four bulges in one row and five in the other row.

[0058] For the test specimens made from the laminated packaging material of Examples 1 and 2 and Comparative Example 1, the height of the bulging portion was set to 4.5 mm, 5.0 mm, and 5.5 mm.

[0059] Then, each test specimen was visually inspected for the presence or absence of cracks and pinholes in the bulging area.

[0060] The results of evaluation tests 1 and 2 are shown in Table 1.

[0061] [Table 1]

[0062] In the columns for Evaluation Test 1 and Evaluation Test 2 in Table 1, ○ indicates that no pinholes or cracks occurred in the nine bulges of each test specimen, P indicates that a pinhole occurred in at least one of the nine bulges of each test specimen, and × indicates that a crack occurred in at least one of the nine bulges of each test specimen.

[0063] [Evaluation Test 3] From five sets of test specimens that formed a bulge with a height of 4.5 mm under the conditions of Evaluation Test 1, test specimens that did not exhibit cracks or pinholes were selected. After sterilization treatment at 125°C for 30 minutes in a hot water heating and pressurizing sterilizer, the presence or absence of delamination in the test specimens was visually confirmed.

[0064] The results of Evaluation Test 3 are also shown in Table 1. In the Evaluation Test 3 column of Table 1, ○ indicates that no delamination occurred in each test specimen, and × indicates that delamination occurred in each test specimen.

[0065] [Evaluation Test 4] Two square test pieces (500) with sides of 100 mm were prepared from the laminated packaging material of Examples 1-2 and Comparative Example 1. A cross-shaped slit (501) was formed in the test piece, with two straight sections (502) intersecting at the center of its length, as shown in Figure 5. The lengths of the two straight sections (502) of the slit (501) were each 85 mm, and both straight sections (502) were located on the diagonals of the test piece (500), with the intersection of the two straight sections (502) located at the center of the test piece (500).

[0066] Then, for each test specimen (500), the amount of curl toward the sealant layer in sections A to D of Figure 5 was measured. The results are shown in Table 2.

[0067] [Table 2]

[0068] [Evaluation Test 5] Two square test pieces (500) with sides of 100 mm were prepared, each made from the laminated packaging material of Examples 1-2 and Comparative Example 1. Cross-shaped slits (501) were formed in these test pieces (500) in the same manner as in Evaluation Test 4.

[0069] Then, each test specimen (500) was subjected to a sterilization treatment at 120°C for 30 minutes using a hot water heating and pressurizing sterilizer. After 1 hour, the amount of curl towards the sealant layer in sections A to D of Figure 5 of each test specimen (500) was measured. The results are shown in Table 3.

[0070] [Table 3]

[0071] [Evaluation Test 6] Two square test pieces (500) with sides of 100 mm were prepared, each made from the laminated packaging material of Examples 1-2 and Comparative Example 1. Cross-shaped slits (501) were formed in these test pieces (500) in the same manner as in Evaluation Test 4.

[0072] Then, each test specimen (500) was subjected to sterilization treatment twice using a hot water heating and pressurizing machine at 120°C for 30 minutes. After 1 hour had passed, the amount of curl towards the sealant layer in sections A to D of Figure 5 of each test specimen (500) was measured. The results are shown in Table 4.

[0073] [Table 4]

[0074] In Tables 2 to 4, ◎ indicates a curl amount of 1.0 mm or less, ○ indicates a curl amount greater than 1.0 mm and 3.0 mm or less, and △ indicates a curl amount greater than 3.0 mm and 7.0 mm or less. [Industrial applicability]

[0075] The laminated material for packaging according to this invention is suitably used as packaging material for forming packaging bodies that package optical lenses such as hydrophilic soft contact lenses, intracrystalline lenses, and small, high-precision vision correction lenses, as well as fragile sheet-like materials such as sheet-like cell cultures. [Explanation of Symbols]

[0076] (1): Laminated material for packaging, (11): Protective resin layer, (12): Adhesive layer, (13): Barrier layer, (14): Adhesive layer, (15): Molding auxiliary resin layer, (16): Adhesive layer, (17): Sealant layer, (2): First packaging material, (20): Swelling part, (21): Bottom wall, (22): Side wall , (23): opening, (24): flange, (3): second packaging material, (30): bulge, (31): bottom wall, (32): side wall, (33): opening, (34): flange, (4): packaging body, (41): accommodation space, (200): first packaging material, (300): second packaging material, (400): packaging body

Claims

1. A laminated material for packaging, having a bottom wall and a bulging portion consisting of a side wall integrally provided to project in one direction from the periphery of the bottom wall, and for forming packaging material that is exposed to a high-temperature atmosphere for sterilization treatment, A laminate for packaging materials, comprising a laminate in which a protective resin layer, a barrier layer, and a sealant layer are laminated in this order from one side, with a molding aid resin layer provided between the barrier layer and the protective resin layer or sealant layer.

2. The packaging laminate according to claim 1, wherein a molding auxiliary resin layer is provided between the barrier layer and the sealant layer.

3. The laminated material for packaging according to claim 2, wherein adhesive layers are provided between the protective resin layer and the barrier layer, between the barrier layer and the molding auxiliary resin layer, and between the molding auxiliary resin layer and the sealant layer.

4. The packaging laminate according to claim 1, wherein the molding auxiliary resin layer is made of a biaxially oriented nylon film.

5. The packaging laminate according to claim 1, wherein the molding auxiliary resin layer is made of a biaxially oriented polyester film.

6. A packaging material that is molded using a laminated material for packaging as described in any one of claims 1 to 5, and has a bulge consisting of a bottom wall and a side wall integrally provided on the periphery of the bottom wall so as to project in one direction, wherein an opening in the bulge is formed surrounded by the protruding end of the side wall, and the protective resin layer of the laminated material for packaging is located on the outer surface side of the bottom wall and the side wall.

7. The packaging material according to claim 6, wherein the bulge height of the bulging portion is 20 to 50% of the circular diameter of the opening.

8. A packaging material formed using a laminated material for packaging as described in any one of claims 1 to 5, and having a bulge consisting of a bottom wall and a side wall integrally provided on the periphery of the bottom wall so as to project in one direction, wherein an opening in the bulge is formed surrounded by the protruding end of the side wall, and the sealant layer of the laminated material for packaging is located on the outer surface side of the bottom wall and the side wall.

9. The packaging material according to claim 8, wherein the bulge height of the bulging portion is 20 to 50% of the circular diameter of the opening.

10. A packaging body wherein the packaging material according to claim 6 has an outward-facing flange connected to the peripheral wall at the opening periphery of the bulge, and the surface of the flange opposite to the surface facing the bottom wall of the bulge is covered with a sealant layer; the packaging material according to claim 8 has an outward-facing flange connected to the peripheral wall at the opening periphery of the bulge, and the surface of the flange facing the bottom wall of the bulge is covered with a sealant layer; the height of the bulge of the packaging material according to claim 8 is lower than the height of the internal space of the bulge of the packaging material according to claim 6; the bulge of the packaging material according to claim 8 is inserted into the space within the bulge of the packaging material according to claim 6 to form a storage space between the two packaging materials; and with contents placed in the storage space, the flanges of the two packaging materials are heat-sealed together using the sealant layers of the two packaging materials.

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