Laminates and packaging

Abstract

This laminate has: a sealant layer (12a) which is the innermost layer and formed of a polyethylene-based resin; a base material layer (12b) formed of a polyethylene-based resin; and a heat resistant layer (12c) which is the outermost layer and formed on the outer surface of the base material layer (12b). This package body (10) has an infolded member (12). In the package body (10), at least the infolded member (12) is formed from the laminate.

Description

TECHNICAL FIELD

[0001] The present invention relates to a laminate and a package. This application claims priority based on Japanese Patent Application No. 2021-4162 filed in Japan on January 14, 2021, the entire content of which is incorporated herein by reference. BACKGROUND ART

[0002] Paragraph 0009 of Patent Document 1 describes a self-supporting standing pouch in which a double-folded bottom film is disposed between a pair of body films. Further, Paragraph 0012 of Patent Document 2 describes a gusset bag in which a pair of side sheets each having a central fold line formed inward are arranged between a front sheet and a rear sheet, such that the bag becomes flat when the side sheets are folded, and can be expanded into a substantially rectangular parallelepiped shape when the side sheets are unfolded. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 Japanese Unexamined Patent Application Publication No. 2006-7630 PATENT DOCUMENT 2 Japanese Unexamined Patent Application Publication No. 2006-341876 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] Conventional composite films used for body members and bottom members in packages have a heat-adhesive resin (sealant) layer such as polyethylene (PE) on the inner surface, and a base material such as polyethylene terephthalate (PET) having higher heat resistance than the sealant is laminated on the outer surface. When the body members are heat-bonded to each other, or the body member and the bottom member are heat-bonded, the sealant is melted to join the inner surfaces of the composite films. However, packages containing different types of resins have a problem that they are difficult to recycle as plastic containers and packaging.

[0005] In recent years, monomaterial packaging using a single resin has been advocated to facilitate recycling. However, when forming packaging from a film made of a single resin, adhesion (blocking) can occur where the outer surfaces of the films overlap when joining (sealing) the inner surfaces of the films. When blocking occurs, it can be difficult to open the overlapping films when filling the packaging with contents. If the films are joined at a lower processing temperature to suppress blocking, the processing time increases, leading to a decrease in productivity.

[0006] This invention has been made in view of the above circumstances, and aims to provide a laminate in which internal bonding (sealing) is easy and external adhesion (blocking) is suppressed, and a packaging body using the same. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present invention provides a laminate characterized by having an innermost sealant layer formed from a polyethylene resin, a base material layer formed from a polyethylene resin, and an outermost heat-resistant layer formed on the outer surface of the base material layer.

[0008] The heat-resistant layer may be formed from varnish. The sealant layer may be formed from an unstretched polyethylene resin, and the base layer may be formed from a stretched polyethylene resin. A printed layer or an adhesive layer may be provided between the sealant layer and the substrate layer. 95% or more by weight of the laminate may be made of polyethylene resin.

[0009] Furthermore, the present invention provides a packaging body having a folded member that is folded so that its outer surface faces the other by a fold line, characterized in that at least the folded member is formed from the laminate.

[0010] One or more of the folding members may be placed between a pair of flat planar members. The planar member may be a laminate having an innermost sealant layer made of polyethylene resin and an outermost base material layer made of polyethylene resin. A packaging body in which a bottom member folded in half along a fold line is sandwiched between a pair of body members, wherein the bottom member is the folded member and the body members are the planar members.

[0011] The heat-resistant layer may be locally formed on the outer surface of the folded member in a region corresponding to the area where the inner surface of the folded member is joined. At the end of the folded member in the direction along the fold line, the heat-resistant layer may be omitted and the base material layers may be joined together. [Effects of the Invention]

[0012] According to the present invention, since a heat-resistant layer is provided on the outer surface of a laminate having a sealant layer on its inner surface, the inner surface can be easily joined (sealed), and adhesion (blocking) on ​​the outer surface can be suppressed. [Brief explanation of the drawing]

[0013] [Figure 1] This is a front view illustrating the packaging of the first embodiment. [Figure 2] This is a cross-sectional view along the line II-II in Figure 1. [Figure 3] This is a front view illustrating a packaging body according to a second embodiment. [Figure 4] This is a cross-sectional view along the line IV-IV in Figure 3. [Figure 5] This is a schematic cross-sectional view of the laminate of the embodiment. [Modes for carrying out the invention]

[0014] The present invention will be described below with reference to the drawings, based on preferred embodiments.

[0015] FIG. 1 shows the external appearance of the package 10 according to the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. The front and rear of the package 10 are perpendicular to the paper surface in FIG. 1. The front and rear of the package 10 correspond to the left and right in FIG. 2. The package 10 is formed from a pair of planar members 11 and a folding member 12 that is folded in two along a fold line 13. The planar members 11 form the body member of the package 10. The folding member 12 forms the bottom member of the package 10. The folding member 12 is folded along the fold line 13 such that the outer surfaces thereof face each other.

[0016] One planar member 11 is disposed on each of the front and rear sides of the package 10. The planar members 11 on the front and rear of the package 10 may be formed to have the same planar shape as each other. Above the fold line 13, body seal portions 14 are formed on the left and right sides of the package 10. At the body seal portions 14, the inner surfaces of the front and rear planar members 11 are joined to each other along the left and right peripheral edges of the package 10.

[0017] The folding member 12 is sandwiched between the front and rear planar members 11 with the fold line 13 facing upward. In the plan view shown in FIG. 1, the fold line 13 is the upper end of the folding member 12. Below the fold line 13, a bottom seal portion 15 is formed, in which the inner surface of the folding member 12 is joined to the inner surfaces of the planar members 11. As shown in FIG. 2, the bottom seal portion 15 joins each portion of the folding member 12 defined by the fold line 13 to the planar member 11 on the same side thereof.

[0018] The unsealed portion surrounded by the body seal portions 14 and the bottom seal portion 15 of the package 10 forms a storage space for contents inside the package 10. When the folding member 12 is spread forward and rearward, the package 10 can stand on its own with the folding member 12 positioned on the vertically lower side. The inner surfaces of the planar members 11 and the folding member 12 are the surfaces on the side in contact with the storage space for the contents. The outer surfaces of the planar members 11 and the folding member 12 are the surfaces on the side opposite to the inner surfaces.

[0019] The planar member 11 is formed from a laminate having a sealant layer 11a made of polyethylene resin and a base layer 11b made of polyethylene resin. The sealant layer 11a is the innermost layer located on the inner surface of the planar member 11. The base layer 11b may be the outermost layer of the planar member 11.

[0020] The folding member 12 is formed from a laminate having a sealant layer 12a made of polyethylene resin, a base layer 12b made of polyethylene resin, and a heat-resistant layer 12c formed on the outer surface of the base layer 12b. The sealant layer 12a is the innermost layer located on the inner surface of the folding member 12. The heat-resistant layer 12c is the outermost layer located on the outer surface of the folding member 12.

[0021] The sealant layers 11a and 12a are arranged as the innermost layer on the inner surface of the laminate forming the planar member 11 or the folded member 12. The sealant layer 11a of the planar member 11 can be used for joining planar members 11 together, and for joining the planar member 11 and the folded member 12. The sealant layer 12a of the folded member 12 can be used for joining the planar member 11 and the folded member 12.

[0022] The sealant layers 11a and 12a are preferably formed from an unstretched polyethylene resin. Specific examples of materials for forming the sealant layers 11a and 12a include relatively low-density polyethylene resins such as linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE). The material forming the sealant layers 11a and 12a may be a single polyethylene resin or a blend of two or more polyethylene resins. The thickness of the sealant layers 11a and 12a is not particularly limited, but for example, it may be about 60 to 180 μm.

[0023] The base material layers 11b and 12b are laminated on the outer side in the thickness direction of the sealant layers 11a and 12a in the laminate that forms the planar member 11 or the folded member 12. Preferably, the base material layers 11b and 12b can reinforce the mechanical strength of the laminate when the laminate is transported in the length direction for use. In conventional laminated films, PET film or the like was used as the base material layer, but in the laminate of this embodiment, polyethylene resin film is used as the base material layer 11b and 12b, which improves recyclability.

[0024] The base layers 11b and 12b are preferably formed from stretched polyethylene resin. Specific examples of materials for forming the base layers 11b and 12b include relatively high-density polyethylene resins such as medium-density polyethylene (MDPE) and high-density polyethylene (HDPE). The material forming the base layers 11b and 12b may be a single type of polyethylene resin or a blend of two or more types of polyethylene resins. The thickness of the base layers 11b and 12b is not particularly limited, but for example, it may be about 10 to 50 μm.

[0025] The polyethylene resin used in the sealant layers 11a, 12a or the base layers 11b, 12b may be a homopolymer of ethylene or a copolymer mainly composed of ethylene. Examples of monomers other than ethylene (comonomers) include one or more α-olefins such as 1-butene, 1-hexene, and 1-octene, cyclic olefins such as norbornene, and vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid. If the polyethylene resin is copolymerized with a monomer having an ester group such as vinyl acetate, some of the ester groups may be saponified to form a copolymer containing vinyl alcohol.

[0026] The proportion of ethylene in the constituent monomers of the polyethylene resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The ethylene or comonomer may be a compound derived from fossil resources such as petroleum, or a compound derived from biomass such as plants. The resin contained in the sealant layer 11a, 12a or the base layer 11b, 12b may consist only of polyethylene resin. The sealant layer 11a, 12a or the base layer 11b, 12b may contain additives other than resin. Additives are not particularly limited, but examples include antioxidants, lubricants, antiblocking agents, flame retardants, ultraviolet absorbers, light stabilizers, antistatic agents, colorants, crosslinking agents, etc.

[0027] At least a portion of the polyethylene resin may include recycled polyethylene resin. The recycled polyethylene resin may be polyethylene resin produced by chemical recycling, in which used polyethylene resin is broken down into monomers such as ethylene and then repolymerized. It may also be polyethylene resin produced by mechanical recycling, in which used polyethylene resin is regenerated as a polymer through processes such as crushing and sorting. Recycled polyethylene resin and new polyethylene resin may be mixed and used.

[0028] The proportion of the laminate thickness occupied by the sealant layers 11a and 12a is preferably 50% or more, and may be around 60%, 70%, 80%, 90%, 95%, or an intermediate value therein. The proportion of the laminate thickness occupied by the combined thickness of the sealant layers 11a and 12a and the base material layers 11b and 12b is preferably 50% or more, and may be around 60%, 70%, 80%, 90%, 95%, 99%, or an intermediate value therein.

[0029] The heat-resistant layer 12c can be any layer that has better heat resistance than the polyethylene resin forming the base layer 12b. The heat-resistant layer 12c is formed at least on the outer surface of the folded member 12. This makes it possible to suppress adhesion (blocking) of the outer surface of the folded member 12 even when the folded members 12 overlap when joining (sealing) the inner surface of the folded member 12 to the planar member 11.

[0030] The heat-resistant layer 12c may be formed from inorganic compounds such as alumina and silica, or from organic compounds containing metals, by vapor deposition, coating, or the like. For example, it is also possible to synthesize the material for the heat-resistant layer 12c on the base layer 12b from a paint that serves as the raw material for the heat-resistant layer 12c using a sol-gel method or the like. Examples of raw materials for the sol-gel method include metal alkoxides. The material for the heat-resistant layer 12c is preferably capable of curing at relatively low temperatures, such as room temperature, using a catalyst or moisture in the air, in order to match the heat resistance of the polyethylene resin.

[0031] The heat-resistant layer 12c may be formed from varnish. A heat-resistant varnish that can form the heat-resistant layer 12c by drying, curing, etc., is preferred. The varnish may contain a resin and a solvent, or it may contain a solvent-free resin. The resin used in the varnish is not particularly limited, but examples include one or more of urethane resin, acrylic resin, epoxy resin, polymethylpentene resin, cyclic olefin resin, unsaturated polyester resin, alkyd resin, polyimide resin, polyamide-imide resin, and polyamide resin. The solvent of the varnish can be appropriately selected considering the performance when applied to polyethylene resin, etc.

[0032] The heat-resistant layer 12c can be formed directly between it and the base layer 12b without an adhesive layer or the like. The heat-resistant layer 12c may be formed over the entire surface of the base layer 12b. The heat-resistant layer 12c may be formed over a portion of the base layer 12b. For example, the heat-resistant layer 12c may be locally formed in the area of ​​the outer surface of the folding member 12 that corresponds to the bottom seal portion 15 where the inner surface of the folding member 12 is joined. In areas where the heat-resistant layer 12c is not formed, the base layer 12b may be exposed on the outer surface of the folding member 12.

[0033] It is preferable that the folding member 12 does not easily open forward or backward at the left and right side ends 15a of the bottom seal portion 15. Although not shown in particular, notches or through holes may be formed in the folding member 12, and the front and rear planar members 11 may be joined through the notches or through holes. Alternatively, the outer surfaces of the folding member 12 may be locally joined (sealed) at the left and right side ends 15a of the bottom seal portion 15. In this case, the notches or through holes of the folding member 12 can be omitted. In the area where the outer surfaces of the folding member 12 are joined (sealed), the heat-resistant layer 12c may be omitted, and the base material layers 12b may be joined facing each other.

[0034] The thickness of the heat-resistant layer 12c is preferably, for example, 10 μm or less. Specific examples of the thickness of the heat-resistant layer 12c are not particularly limited, but may be approximately 10 μm, 8 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.5 μm, 0.2 μm, 0.1 μm, or intermediate values ​​therebetween.

[0035] The heat-resistant layer 12c may include markings for controlling the transport and processing of the laminate in the bag-making process, which involves sandwiching the folding member 12 between the planar members 11. By detecting the markings with a sensor, the transport speed and position of the laminate can be detected. The heat-resistant layer 12c may contain additives such as colorants and light absorbers to facilitate optical detection by the sensor. The heat-resistant layer 12c formed as a marking may be formed in a location different from the seal portion. It is also possible to mark an area where there is no heat-resistant layer 12c locally. Furthermore, the heat-resistant layer 12c can be formed in a shape that represents information or design, such as letters, symbols, or patterns.

[0036] The laminate forming the planar member 11 or the folded member 12 may include, in addition to the heat-resistant layer 12c described above, other dissimilar material layers such as a vapor-deposited layer, a printed layer, a coated layer, or an adhesive layer. Examples of dissimilar materials include metals such as aluminum, and inorganic compounds such as silica and alumina. The printed layer, coated layer, adhesive layer, etc., may include polymer materials other than polyethylene as materials for inks, paints, adhesives, etc. Dissimilar material layers such as the printed layer and adhesive layer may be placed between the sealant layers 11a, 12a and the base material layers 11b, 12b of the laminate. The method for forming the laminate is not particularly limited, but examples include dry lamination, extrusion lamination, thermal lamination, co-extrusion, and coating. Different methods may be used to laminate each layer.

[0037] The sealant layers 11a, 12a and the substrate layers 11b, 12b may be laminated with an adhesive layer in between. The adhesive layer may be formed from an adhesive or from an anchor coating agent. The material for forming the adhesive layer is not particularly limited, but examples include urethane compounds, epoxy compounds, isocyanate compounds, polyethyleneimine, and organotitanium compounds such as titanium alkoxide. The thickness of the adhesive layer may be, for example, about 0.1 to 10 μm, about 1 to 6 μm, or about 3 to 4 μm. The adhesive layer may contain resin or it may be a resin-free adhesive layer.

[0038] A printed layer may be present on the outer surface of the sealant layers 11a, 12a, the inner surface of the substrate layers 11b, 12b, or the outer surface of the substrate layers 11b, 12b. The printed layer can be formed by printing ink in a solid or patterned manner using printing methods such as gravure printing, letterpress printing, offset printing, screen printing, or inkjet printing. The thickness of the printed layer is not particularly limited, but is typically around 0.5 to 10 μm. The printed layer may be formed over the entire surface of the laminate or on a part of the surface of the laminate. Two or more printed layers may be stacked on top of each other.

[0039] The ink used to form the printed layer may contain a coloring agent such as a pigment or dye, and a binder. The binder is not particularly limited, but examples include polyamide, polyurethane, polyester, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, acrylic polymer, polybutadiene, and cyclocompound rubber. The ink may also contain a solvent such as water, organic solvent, or vegetable oil. After printing, the ink can be dried by the evaporation of the solvent or curing of the ink. Heating or ultraviolet irradiation may be used to accelerate the drying of the ink. The printed layer may contain a resin, or it may be a resin-free printed layer.

[0040] In the laminate of the embodiment, thin layers such as the heat-resistant layer 12c, the printing layer, and the adhesive layer may be resin-containing layers. Preferably, the other relatively thick layers are only polyethylene resin layers such as the sealant layers 11a, 12a and the base layers 11b, 12b. The thickness of the thin layers can be, for example, 10 μm or less, or 5 μm or less, as the thickness of each individual layer or the total thickness of all layers. 95% by weight or more of the laminate of the embodiment may be formed from polyethylene resin.

[0041] The laminate of this embodiment can be formed without laminating other resin films, except for using polyethylene-based resin films for the sealant layers 11a, 12a and the base layers 11b, 12b. Therefore, there is no need to separate different types of resin films when disposing of the laminate, making recycling easier. Other resin films include, but are not limited to, polypropylene-based films, polyester-based films, and nylon-based films.

[0042] The method for manufacturing a laminate having a heat-resistant layer 12c is not particularly limited, but may include, for example, (1) a step of forming a printed layer on the outer surface of the sealant layer 12a or the inner surface of the base layer 12b, (2) a step of forming a printed layer on the outer surface of the base layer 12b, (3) a step of forming the outermost heat-resistant layer 12c on the outer surface of the base layer 12b, and (4) a step of laminating the sealant layer 12a on the inner surface of the base layer 12b via an adhesive layer.

[0043] Steps (1) and (2) may be performed individually or both. The order of steps (1) to (4) is not particularly limited, except that step (1) is performed before step (4), and step (2) is performed before step (3). For example, the order of steps (1) and (3) is not limited, and they may be performed in parallel. When steps (2) and (3) are performed, the heat-resistant layer 12c may be applied on top of the printing layer on the outer surface of the substrate layer 12b. The order of steps (3) and (4) is not limited, and they may be performed in parallel. If a printing layer is not formed on the laminate, steps (1) and (2) may be omitted.

[0044] Different polyethylene resin films are used for the sealant layer 12a and the base layer 12b. Different material layers such as the heat-resistant layer 12c, printing layer, and adhesive layer can be formed by laminating materials on the film using film processing techniques such as coating, vapor deposition, and printing. The resulting laminate may have, for example, five layers: "sealant layer / adhesive layer / printing layer / base layer / heat-resistant layer" or "sealant layer / printing layer / adhesive layer / base layer / heat-resistant layer". The resulting laminate may be in the form of a flat sheet or wound into a roll.

[0045] Figure 5 is a schematic cross-sectional view of the laminate according to the embodiment. As shown in Figure 5, the laminate consists of a sealant layer 12a, an intermediate layer 12d, a base layer 12b, and a heat-resistant layer 12c, which are laminated in this order. The intermediate layer 12d is, for example, a printing layer or an adhesive layer.

[0046] The dimensions of the packaging 10 are not particularly limited, but for example, in the case of a refillable container, the height in the vertical direction is about 100-500 mm, the width in the horizontal direction is about 70-300 mm, and the filling volume is about 100 cm. 3 ~5000cm 3 The degree can be mentioned. The state of the contents can be fluids such as liquids, powders, and granules. The type of contents is not particularly limited, but can be detergents, chemicals, cosmetics, pharmaceuticals, beverages, seasonings, inks, paints, fuels, etc.

[0047] The packaging 10 may have a filling opening, a dispensing spout, etc. In the example shown in Figure 1, the front and rear planar members 11 are open at the top of the packaging 10, allowing it to be used for filling or dispensing the contents. After filling the contents, the planar members 11 may be joined together to seal the packaging 10. When opening the packaging 10, the part where the planar members 11 were joined may be cut off and removed by tearing or other means. Although not specifically shown, the dispensing spout may be formed in a shape that protrudes thinly from the top or corner of the packaging 10.

[0048] The method for manufacturing the packaging 10 is not particularly limited, but it may include a method that includes the steps of forming a fold line 13 on the folding member 12, sandwiching the folding member 12 between a pair of planar members 11, and joining the inner surfaces of the laminate to form a body seal portion 14 and a bottom seal portion 15. The raw materials of the planar members 11 and the folding member 12 may be a long web extending along the direction of the fold line 13. The web may be transported along its longitudinal direction. The packaging 10 formed on the web can be separated into individual packaging bodies 10 by cutting in the longitudinal direction, the intersecting direction (width direction), or other directions.

[0049] The raw material before forming the fold line 13 on the folding member 12 may be prepared in advance as a laminate having a sealant layer 12a, a base material layer 12b, and a heat-resistant layer 12c. If the heat-resistant layer 12c is to be formed in a predetermined area of ​​the raw material, the necessary area may be determined in advance and the heat-resistant layer 12c may be formed therein.

[0050] The step of forming the heat-resistant layer 12c may be performed at a stage such as forming the packaging body 10, as long as it is before the step of joining the inner surfaces of the laminate. In this case, the raw material of the folded member 12 may be prepared as a laminate having a sealant layer 12a and a base material layer 12b, but without the heat-resistant layer 12c. Since the heat-resistant layer 12c is formed on the outer surface of the folded member 12 on the side facing each other by the fold line 13, it is preferable to form the heat-resistant layer 12c before forming the fold line 13.

[0051] The packaging body 10 of the first embodiment has a bottom portion formed by sandwiching a folding member 12 between planar members 11 facing each other in the front-rear direction, but the position, shape, number, etc. of the folding member 12 are arbitrary. In a packaging body having a folding member 12 that is folded so that its outer surface faces the other by a fold line 13, it is sufficient that at least the folding member 12 is formed from the above-mentioned laminate having a heat-resistant layer 12c on its outer surface.

[0052] A folding member 12 may be provided between a pair of flat planar members 11. The number of folding members 12 is not particularly limited; for example, there may be one, two, three, four, etc., but there may be more. The folding members 12 may be arranged along one side of the planar member 11. The folding members 12 may be arranged along two opposing sides or two adjacent sides of the planar member 11. For a substantially rectangular planar member 11, folding members 12 may be arranged on each of three or four sides. Two or more folding members 12 may be superimposed in the front-to-back direction of the planar member 11.

[0053] The fold lines of the folding member 12 are not limited to the fold lines 13 in the direction of the long side in the embodiment, but may also have fold lines in the direction of the short side, diagonal directions, etc. For example, when the folding members 12 are arranged on three or four sides of the planar member 11, the folding members 12 that are joined with the front and rear planar members 11 and the left and right folding members 12 may have diagonal fold lines at the four corners of the rectangle (see paragraphs 0025 to 0026 of Patent Document 2). When joining (sealing) the inner surfaces of the folding members 12, the joining is not limited to joining with the planar member 11, but may also have points where the folding members 12 are joined with each other.

[0054] An example of a packaging body 20 of the second embodiment, shown in Figures 3 and 4, is one in which folding members 12 are arranged on two opposing sides of a planar member 11. Figure 3 shows the external appearance of the packaging body 20 of the second embodiment. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. The packaging body 20 comprises a pair of planar members 11 facing each other front and back (top and bottom in Figure 4), and folding members 12 arranged on the left and right sides between the pair of planar members 11. The upper and lower planar members 11 and the left and right folding members 12 are joined via a vertical seal portion 21 to form a cylindrical shape.

[0055] The planar member 11 and the folded member 12 of the packaging body 20 can be formed from a laminate similar to that of the first embodiment. The laminate forming the planar member 11 has a sealant layer 11a and a base material layer 11b. The laminate forming the folded member 12 has an innermost sealant layer 12a, an outer base material layer 12b, and an outermost heat-resistant layer 12c. Although not specifically shown, these laminates may also have adhesive layers, printed layers, etc., as described in the first embodiment.

[0056] In the packaging 20 of the second embodiment, as shown in Figure 3, the upper and lower ends of the planar member 11 are joined by horizontal sealing portions 22. The left and right folding members 12 have fold lines 13 extending vertically and facing inward. As a result, the packaging 20 can be made flat by folding the folding members 12 in half, and can be expanded into a roughly rectangular parallelepiped shape by unfolding the folding members 12 front to back.

[0057] End seal portions 23 may be formed at both the upper and lower ends of the folded member 12 in the direction along the fold line 13. The end seal portions 23 can be formed as extensions to the left and right of the lateral seal portions 22. In at least one of the end seal portions 23, the heat-resistant layer 12c may be omitted and the base material layers 12b may be joined together. In this case, the end seal portions 23 can be formed not only by joining the front and rear planar members 11 and the inner surfaces of the folded member 12, but also by joining (sealing) the outer surfaces of the opposing folded members 12 via the fold line 13.

[0058] The four corners of the packaging body 20 may be provided with diagonal sealing portions 24 that connect the vertical sealing portion 21 and the horizontal sealing portion 22 at an angle of approximately 45°. In the areas where the vertical sealing portion 21 and the diagonal sealing portion 24 are formed, it is preferable to form a heat-resistant layer 12c on the outer surface of the folding member 12 in order to prevent adhesion (blocking) of opposing folding members 12 via the fold line 13.

[0059] If the packaging 20 has an oblique seal portion 24, the contents will not reach the area between the oblique seal portion 24 and the end seal portion 23. For this reason, it is possible to cut off the triangular portion including the end seal portion 23 on the outside of the oblique seal portion 24. If the packaging 20 does not have an oblique seal portion 24, the vertical seal portions 21 at the four corners of the planar member 11 will contact the end seal portion 23, thereby sealing the perimeter of the packaging 20.

[0060] The method for recycling the laminate or packaging of the embodiment after use is not particularly limited, but can be appropriately selected depending on the condition at the time of collection, etc. Since the laminate of the embodiment can have a high proportion of polyethylene resin, both chemical recycling and mechanical recycling as described above are possible. By recycling the laminate or packaging of the embodiment, it is also possible to regenerate similar products such as laminates or packaging. The recycled material may be used in products such as paints, molded products, and hydrocarbon oils.

[0061] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. Modifications include adding, substituting, omitting, or otherwise changing the components in each embodiment. It is also possible to combine components used in different embodiments as appropriate.

[0062] The laminate of the embodiment is a laminated film mainly composed of polyethylene resin and is not limited to packaging such as pouches, bags, and containers, but can be used for various applications. If the laminate is a flexible laminated film, it can form a flexible packaging. The packaging may be formed solely from the above-mentioned laminate, or it may be combined with auxiliary components such as labels, tags, straws, and outer boxes. From a recycling standpoint, it is preferable that the auxiliary components can be separated from the packaging.

[0063] It is also possible to laminate a heat-resistant layer similar to the heat-resistant layer 12c of the folded member 12 onto the outer surface of the planar member 11. For example, a heat-resistant layer may be formed on the outer surface of the planar member 11 in the region corresponding to the area where the inner surface of the planar member 11 is joined, prior to joining (sealing) the planar member 11. Furthermore, a heat-resistant layer may be formed on the outer surface of the planar member 11 for the purpose of marking, display, etc. It is also possible to use a laminate with a heat-resistant layer formed on its entire surface as the planar member 11. [Industrial applicability]

[0064] According to the present invention, the internal surface can be easily joined (sealed), and adhesion (blocking) of the external surface can be suppressed, making it suitable for industrial use. [Explanation of Symbols]

[0065] 10,20 Packaging 11 Planar members 11a, 12a sealant layer 11b,12b Base material layer 12 Folding members 12c heat resistant layer 13 Fold lines 14 Body seal section 15 Bottom seal section 15a Side end 21 Vertical seal section 22 Side seal section 23 End sealing portion 24 Diagonal seal section

Claims

1. A laminate comprising: an innermost sealant layer formed from a first polyethylene resin; a base layer formed from a second polyethylene resin having a relatively higher density than the first polyethylene resin; and an outermost heat-resistant layer formed on the outer surface of the base layer, The heat-resistant layer is formed of alumina or silica, and the thickness of the heat-resistant layer is 10 μm or less. The ratio of the thickness of the sealant layer to the thickness of the laminate is 70% or more. A laminate characterized in that 95% or more by weight of the laminate is made of polyethylene resin.

2. The laminate according to claim 1, characterized in that the first polyethylene resin forming the sealant layer is an unstretched polyethylene resin, and the second polyethylene resin forming the base layer is a stretched polyethylene resin.

3. The laminate according to claim 1 or 2, characterized in that it has a printed layer or an adhesive layer between the sealant layer and the substrate layer.

4. A packaging body having a folded member that is folded so that its outer surface faces the other by a fold line, wherein at least the folded member is formed from a laminate as described in any one of claims 1 to 3.

5. The packaging according to claim 4, characterized in that it has one or more folding members between a pair of flat planar members.

6. The packaging according to claim 5, characterized in that the planar member is a laminate having an innermost sealant layer formed from polyethylene resin and an outermost base material layer formed from polyethylene resin.

7. The packaging body according to claim 5 or 6, wherein a bottom member folded in half along a fold line is sandwiched between a pair of body members, the bottom member being the folded member and the body members being the planar member.

8. The packaging according to any one of claims 4 to 7, characterized in that the heat-resistant layer is locally formed in a region of the outer surface of the folded member that corresponds to the portion where the inner surface of the folded member is joined.

9. The packaging body according to any one of claims 4 to 8, characterized in that the heat-resistant layer is omitted at the end of the folded member in the direction along the fold line, and the base material layers are joined together.

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