Laminate, packaging bag and package

Abstract

To provide a laminate having sufficiently high reflectance density and improved visibility while using a recycled PET film.SOLUTION: There is provided a laminate provided with a base material film and a sealant layer, wherein the base material film is a recycled polyethylene terephthalate film having a provisional Abbe number Vd, calculated by the following expression (1), of 24.0 to 40.0 when the refractive indices at a wavelength of 550.0 nm, 589.0 nm and 633.0 nm are defined as d1, d2 and d3, respectively. Vd=(d2-1) / (d1-d3) (1)SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a laminate, a packaging bag, and a packaging body. [Background technology]

[0002] Packaging bags with laminates based on recycled polyethylene terephthalate (PET) are environmentally friendly packaging bags, and their active use is expected. For example, Patent Document 1 discloses a PET container that includes recycled PET and has an opaque area on its surface to improve the visibility of the printed surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-059554 Summary of the Invention [Problem to be solved by the invention]

[0004] Known methods for recycling PET include a mechanical recycling method in which PET is treated under high temperature and reduced pressure, and a chemical recycling method in which PET is chemically decomposed. There is concern that the visibility of recycled PET films made through such recycling processes may be lower than that of ordinary PET films due to changes in molecular orientation or the inclusion of trace components. The present disclosure provides a laminate that uses recycled PET films and has a sufficiently high reflection density and improved visibility. The present disclosure also provides a packaging bag and a packaging body that include such a laminate. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a laminate including a base film and a sealant layer, wherein the base film is a recycled polyethylene terephthalate film having a tentative Abbe number Vd of 24.0 to 40.0, calculated by the following formula (1) where d1 is the refractive index at a wavelength of 550.0 nm, d2 is the refractive index at a wavelength of 589.0 nm, and d3 is the refractive index at a wavelength of 633.0 nm. Vd = (d2-1) / (d1-d3) (1)

[0006] In the laminate, the tentative Abbe number calculated using the refractive indexes of the recycled polyethylene terephthalate (recycled PET) film used as the base film is 24.0 to 40.0, where d1 is the refractive index at a wavelength of 550.0 nm, d2 is the refractive index at a wavelength of 589.0 nm, and d3 is the refractive index at a wavelength of 633.0 nm. By using a recycled PET film having a tentative Abbe number in this range as the base film, a laminate with high reflection density and improved visibility can be obtained.

[0007] According to one aspect of the present disclosure, there is provided a packaging bag including the laminate. By including the laminate, the packaging bag can have improved surface visibility.

[0008] According to one aspect of the present disclosure, there is provided a package including the packaging bag and an item accommodated in the accommodation portion of the packaging bag. The package includes the laminate, thereby improving the visibility of the surface. Effect of the Invention

[0009] The present disclosure provides a laminate that uses a recycled PET film and yet has a sufficiently high reflection density and improved visibility. The present disclosure also provides a packaging bag and a packaging body including such a laminate. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing an example of a cross section of a laminate. [Diagram 2] FIG. 2 is a diagram showing an example of a cross section of a laminate. [Diagram 3] FIG. 1 is a diagram showing an example of a packaging bag. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments of the present disclosure will be described. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. The upper or lower limit of the numerical range specified in this specification may be replaced with any value shown in the examples. In addition, the upper and lower limit values ​​described individually may be arbitrarily combined. Unless otherwise specified, the materials or components exemplified in this specification may be used alone or in combination of two or more types. In the description, the same elements or elements having the same functions are given the same reference numerals, and duplicated descriptions are omitted. In addition, the positional relationships such as up, down, left, and right used in the description are based on the positional relationships shown in the drawings, unless otherwise specified.

[0012] 1 is a diagram showing an example of a cross section of a laminate according to one embodiment. The laminate 100 has a sealant layer 30 on one surface of a base film 10. An adhesive layer S is interposed between the base film 10 and the sealant layer 30.

[0013] The base film 10 includes at least one selected from a mechanically recycled polyethylene terephthalate film (MR-PET film) and a chemically recycled polyethylene terephthalate film (CR-PET film). The MR-PET film can be obtained by crushing and washing polyethylene terephthalate (PET), further treating it at high temperature and reduced pressure for a certain period of time, removing impurities by melt filtration, returning it to PET resin again, and processing it into a film. The CR-PET film can be obtained by crushing and washing PET, further chemically decomposing the obtained PET raw material, returning it to PET resin again, and processing it into a film. By using the recycled PET film manufactured through these recycling processes as the base film 10, it is possible to reduce the consumption of plastic resources and the CO2 emissions during PET manufacturing, and obtain an environmentally friendly laminate 100.

[0014] The thickness of the base film 10 may be 9 to 100 μm, 9 to 25 μm, or 12 to 16 μm. The thickness of the base film 10 may be adjusted depending on the application or the desired characteristics. If the thickness is too thick, the sealing performance during packaging may decrease, and the flexibility of the package may decrease, which may cause problems during packaging. If the thickness is too thin, the package may not have sufficient stiffness, and problems such as wrinkles may easily occur during packaging.

[0015] The base film 10 may be a stretched film or an unstretched film. The stretching direction may be the MD direction or the TD direction. The stretching method may be any method such as uniaxial stretching or biaxial stretching, as long as it can provide a film with stable dimensions.

[0016] The reflection density of the base film 10 may be 1.8 to 2.5, or 2.0 to 2.3. The reflection density is a type of optical density, and is calculated as -log10 (reflectance) using the reflectance (=amount of light reflected from the reflecting surface / amount of light incident on the reflecting surface). For example, when the reflectance is 10%, the reflection density is calculated as -log10(0.1)=1, and when the reflectance is 1%, the reflection density is calculated as -log10(0.01)=2. Conversely, when the reflection density is 0.5 or more, the reflectance is (1 / 10)1 / 2 (=about 31.6%) or less. Thus, the higher the reflection density, the lower the reflectance from the surface and the higher the contrast, thereby improving visibility. The reflection density can be measured, for example, using a Macbeth densitometer (product name: RD-918, manufactured by GretagMacbeth).

[0017] The refractive index d1 at a wavelength of 550.0 nm, the refractive index d2 at a wavelength of 589.0 nm, and the refractive index d3 at a wavelength of 633.0 nm of the base film 10 are measured, and the tentative Abbe number Vd represented by formula (1) can be calculated from the obtained three refractive index values. The refractive index can be measured, for example, using a reflection spectroscopic film thickness meter (product name: FE-3000, manufactured by Otsuka Electronics Co., Ltd.). Vd = (d2-1) / (d1-d3) (1)

[0018] The Abbe number is an index indicating the dispersibility of light, and is defined based on JIS B 7090:1999 "Optics and optical instruments - Reference wavelengths" using the refractive index values ​​at wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm. In the present disclosure, the tentative Abbe number Vd is calculated from the refractive index values ​​at wavelengths of 550.0 nm, 589.0 nm, and 633.0 nm, rather than the wavelengths defined by the JIS. Therefore, the tentative Abbe number Vd can be said to be an index indicating the dispersibility in the wavelength range of 550.0 to 633.0 nm. The higher the value of the tentative Abbe number Vd, the lower the dispersion rate of light in the visible wavelength range (the reciprocal of the tentative Abbe number), and therefore the visibility tends to improve.

[0019] The tentative Abbe number Vd of the base film 10 is 24.0 to 40.0, or alternatively 26.0 to 35.0, or may be 28.0 to 33.0. When the tentative Abbe number Vd of the base film 10 is in this range, the reflection density of the laminate 100 using the base film 10 is sufficiently improved, and the visibility of the surface is improved.

[0020] The refractive index d1 of the base film 10 may be 1.6300 to 1.7100 or 1.6400 to 1.7000. The refractive index d2 may be 1.6200 to 1.7000 or 1.6300 to 1.6900. The refractive index d3 may be 1.61 to 1.6900 or 1.6200 to 1.6800.

[0021] The sealant layer 30 is a layer that imparts heat-sealing properties to the laminate 100. Examples of components of the sealant layer 30 include thermoplastic resins, and specifically, polyolefin resins such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene-α-olefin copolymers, ethylene resins such as ethylene-(meth)acrylic acid copolymers, blends of polyethylene and polybutene, homopolypropylene resin (PP), propylene-ethylene random copolymers, propylene-ethylene block copolymers, and polypropylene resins such as propylene-α-olefin copolymers, and the like can be used. In addition, a mixture of a plurality of these thermoplastic resins may be used. These thermoplastic resins can be appropriately selected depending on the intended use.

[0022] The resin constituting the sealant layer 30 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

[0023] The thickness of the sealant layer 30 is determined depending on the weight of the contents or the shape of the packaging bag, but is preferably about 10 to 100 μm.

[0024] An adhesive layer S is interposed between the base film 10 and the sealant layer 30. Examples of adhesive materials that can be used include polyester-isocyanate resins, urethane resins, and polyether resins. By interposing the adhesive layer S, the base film 10 and the sealant layer 30 can be bonded more firmly.

[0025] The thickness of the adhesive layer S is not particularly limited, and may be, for example, 0.5 to 5 μm, or 2 to 3 μm. When the thickness of the adhesive layer S is 0.5 μm or more, the adhesion between the base film 10 and the sealant layer 30 can be improved, and when it is 5 μm or less, the recyclability of the laminate 100 can be improved.

[0026] The laminate 100 can be formed by any of the known lamination methods, such as a dry lamination method in which a film-like sealant layer 30 made of the above-mentioned thermoplastic resin is laminated on the base film 10 with an adhesive such as a one-component curing or two-component curing urethane adhesive, a non-solvent dry lamination method in which a film-like sealant layer 30 is laminated using a solvent-free adhesive, and an extrusion lamination method in which the above-mentioned thermoplastic resin is heated and melted, extruded in a curtain shape, and laminated. The adhesive used to laminate the sealant layer 30 on the base film 10 forms an adhesive layer S as shown in FIG. 1. The sealant layer 30 may also be directly laminated on the base film 10 without the adhesive layer S.

[0027] A printing layer can be provided on the surface of the base film 10 on the side of the sealant layer 30. The printing layer is provided at a position visible from the outside of the laminate for the purpose of displaying information about the contents, identifying the contents, or improving the design of the packaging bag. The printing method and printing ink are not particularly limited, and are appropriately selected from known printing methods and printing inks in consideration of printability on the film, design such as color tone, adhesion, safety as a food container, and the like. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. From the viewpoints of productivity and high definition of the image, gravure printing is preferred.

[0028] In order to improve the adhesion of the printed layer, the surface of the base film 10 on the printed layer side may be subjected to various pretreatments such as corona treatment, plasma treatment, and frame treatment, or a coating layer such as an easy-adhesion layer may be provided.

[0029] Fig. 2 is a diagram showing an example of a cross section of a laminate according to another embodiment of the present disclosure. As shown in Fig. 2, the laminate 101 includes an intermediate layer 20 between the base film 10 and the sealant layer 30. The configuration of the intermediate layer 20 can be appropriately referred to the contents described above regarding the configuration of the sealant layer 30. By including the intermediate layer 20 in the laminate 101, deformation of the laminate during the manufacture of a packaging bag can be further reduced. A plurality of intermediate layers 20 may be used depending on the application of the laminate 101.

[0030] As shown in Fig. 2, a metal layer 40 may be laminated between the intermediate layer 20 and the sealant layer 30. The metal layer 40 may be laminated between the base film 10 and the intermediate layer 20, taking into consideration the manufacturing conditions. By providing the laminate 101 with the metal layer 40, the puncture strength and gas barrier properties of the laminate can be improved. In addition, the metal layer 40 may be vapor-deposited on the intermediate layer 20 in advance.

[0031] An anchor coat layer may be provided adjacent to at least one selected from the printed layer and the metal layer 40. By providing the anchor coat layer, the adhesion of the printed layer or the metal layer 40 can be increased, and the puncture strength of the laminate 100, 101 can be further improved. The anchor coat layer can be formed by applying an anchor coat agent onto a predetermined layer and drying it. For example, polyester-based polyurethane resin, polyether-based polyurethane resin, etc. can be used as the anchor coat agent. The thickness of the anchor coat layer is not particularly limited and may be 0.1 to 1 μm, or 0.3 to 0.5 μm.

[0032] As the metal layer 40, a known metal foil such as copper foil or aluminum foil can be used. From the viewpoint of improving the gas barrier property or preventing the transmission of visible light and ultraviolet light, it is preferable to use aluminum foil. The thickness of the metal layer 40 may be, for example, 6 to 9 μm. By making the thickness of the metal layer 40 6 μm or more, the puncture strength of the laminate 100 is improved. Therefore, even if a foreign matter adheres to the base film 10 in a package including the laminate 101, the foreign matter can be prevented from appearing on the inner side of the base film 10. Therefore, deterioration of the quality of the contained contents can be suppressed.

[0033] The reflection density of the surface x (surface of the base film 10) of the laminate 100, 101 on the base film 10 side of the laminate 100, 101 can be measured by carrying out the reflection density measurement described above. The lower limit of the reflection density of the laminate 100, 101 may be, for example, 0.19 or 0.20. When the reflection density is in such a range, the visibility of the surface of the laminate 100, 101 can be further improved. The upper limit of the reflection density may be, for example, 0.25 or 0.24.

[0034] 3 is an example of a packaging bag formed using a laminate. The packaging bag 200 includes a sealed portion 211 formed by bonding together the peripheries of a pair of substantially rectangular laminates 100, and a storage portion 218 formed between the pair of laminates 100, 100 by the sealed portion 211. That is, the packaging bag 200 has a side end portion 214, a lower end portion 216, and an upper end portion 217 sealed by the sealed portion 211. The packaging bag 200 includes a storage portion 218 in which an object such as food is stored, in a non-sealed portion 215 surrounded by the sealed portion 211. The object such as food is enclosed in the storage portion 218. The sealed portion 211 at the lower end portion 216 may be sealed after the object is filled in the storage portion 218.

[0035] The pair of laminates 100 are overlapped with the sealant layers 30 facing each other. The pair of laminates 100 may be bonded to each other at the seal portion 211 by an adhesive. The pair of laminates 100 may form the seal portion 211 by bonding the heat seal layers provided on the sealant layers 30 to each other.

[0036] Since the laminate 100 has high surface visibility, important information indicated by the printed layer of the laminate 100 can be clearly displayed. Therefore, the efficiency of visual judgment during product inspection can be improved. In addition, the printed pattern of the product can be clearly displayed. The packaging bag 200 may have any layer provided on the base film 10 and the sealant layer 30 of the laminate 100.

[0037] The procedure for manufacturing a packaging bag 200 (packaging body) using the laminate 100 is described below. A pair of laminates 100 is prepared. In the case of the laminate 100, the sealant layers 30 of the laminates 100 are placed opposite each other, and the sealant layers 30 are bonded together with, for example, a fastener tape interposed therebetween, which serves as the resealing means 230. This forms sealed portions 211 at positions corresponding to the upper end 217 and the side ends 214, 214, and forms a non-sealed portion 215 surrounded by the sealed portions 211 in a U-shape.

[0038] After the sealing portion 211 is formed, the opening means 220 may be formed. For example, the side end portions 214, 214 are formed with easy-to-open processed portions 224, 224 consisting of a group of scars. The easy-to-open processed portions 224 are not limited to a group of scars, and may be V-shaped, U-shaped, I-shaped or other notches. In addition, a half-cut line 221 that serves as a trajectory for cutting from the easy-to-open processed portion 224 may be formed on the surface portion of the laminate 100 between the upper end portion 217 and the resealing means 230. The half-cut line 221 can be formed using a laser beam. After the opening means 220 is formed, the sealing portion 211 is cut and trimmed to separate the package into individual packaging bags.

[0039] Next, the contents are filled from the unsealed lower end 216. Thereafter, the laminates 100 are bonded together at the lower end 216, and a seal portion 211 is also formed at the lower end 216. In this manner, the packaging bag 200 and the package can be manufactured. The half-cut line may be formed before the pair of laminates 100 that have been bonded together are slit to a predetermined width.

[0040] The packaging bag 200 is provided with opening means 220 at the upper end side of the non-sealed portion 215 for cutting open the side ends 214, 214 of the packaging bag 200 and across the space therebetween to open the bag, and resealing means 230 below the opening means 220 for resealing the storage portion 218 after the bag is opened by the opening means 220. The resealing means 230 may appropriately adopt a known structure capable of repeatedly opening and sealing. For example, the resealing means 230 may be a synthetic resin fastener capable of repeatedly sealing by fitting a strip-shaped protrusion into a strip-shaped groove, or may be an adhesive seal.

[0041] The package includes a packaging bag 200 and an object contained in the container 218 of the packaging bag 200. The object may be, for example, food, electronic materials, or electronic equipment. Since the package includes the packaging bag 200, the surface of the package is highly visible, and the appearance during product inspection and the printed pattern of the product can be clearly displayed. Therefore, recycled PET film can be used as the packaging bag, and an environmentally friendly package with high visibility can be provided.

[0042] Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, the laminate 100 and the laminate 101 used in the above description may be appropriately replaced with each other. The laminates 100 and 101 may have any layer or thin film between the base film 10 and the sealant layer 30, between the base film 10 and the intermediate layer 20, or between the intermediate layer 20 and the sealant layer 30, as long as the function of the laminate is not significantly impaired. The shape of the packaging bag 200 and the packaging body is not limited to a four-sided bag. For example, it may be a two-sided bag, a three-sided bag, or a palm-shaped bag, or it may be a standing pouch shape with a bottom tape added.

[0043] The present disclosure includes the following contents. [1] A laminate comprising a base film and a sealant layer, The base film is a recycled polyethylene terephthalate film having a tentative Abbe number Vd of 24.0 to 40.0, calculated by the following formula (1) where d1 is the refractive index at a wavelength of 550.0 nm, d2 is the refractive index at a wavelength of 589.0 nm, and d3 is the refractive index at a wavelength of 633.0 nm. Vd = (d2-1) / (d1-d3) (1) [2] The laminate according to [1], wherein the recycled polyethylene terephthalate film is a mechanically recycled polyethylene terephthalate film. [3] The laminate according to the above [1], wherein the recycled polyethylene terephthalate film has a thickness of 9 to 100 μm. [4] The laminate according to any one of [1] to [3], wherein the reflection density of the surface of the laminate on the base film side is 0.19 to 0.25. [5] A packaging bag comprising the laminate according to any one of [1] to [3] above. [6] A packaging body comprising the packaging bag described in [5] above and an item contained in the storage section of the packaging bag. EXAMPLES

[0044] The present disclosure will be described in more detail below with reference to examples and comparative examples. Note that the present disclosure is not limited to the following examples.

[0045] (Examples 1 to 20, Comparative Examples 1 to 8) [Measurement of refractive index of PET film alone] A commercially available mechanically recycled PET film (MR-PET film) was prepared for the examples, and a commercially available PET film (general PET film) that had not been subjected to a recycling process was prepared for the comparative examples. Each film had a thickness of 12 μm.

[0046] Each PET film was cut into pieces to obtain a film piece of 10 cm x 10 cm. A commercially available black masking tape was attached to one side of the obtained film piece to prevent light reflection from the back side, and a sample piece was prepared. For the part of the obtained sample piece corresponding to the part where the black masking tape was attached on the opposite side of the part where the black masking tape was attached, a reflection spectroscopic film thickness meter (product name: FE-3000, manufactured by Otsuka Electronics Co., Ltd.) was used to focus on the PET sample surface using a microscope lens (magnification 40 times) attached to the device so as to avoid the additives (filler particles) contained in the PET film, and the microscopic reflection spectrum in the spot area (5 μm diameter) in the wavelength range of 230 nm to 800 nm [using two light sources, a D2 (deuterium) lamp and an I2 (halogen) lamp] was measured. Then, the refractive index at each wavelength of 550.0 nm, 589.0 nm, and 633.0 nm was calculated from the obtained reflectance curve using the device analysis software. One sample piece was used for each example or comparative example. The measurement conditions and analysis conditions are as described below.

[0047] <Measurement conditions> Measurement method: Insulation reflectance Measurement mode: Manual Lens: Refrec.40X NA:0.5300 ·Standard reflector: Al VH Filter: Nonfilter Slit: 0.2mm x 2mm

[0048] <Analysis conditions> Material Category: Standard · Algorithm: PCB analysis (fit) Smoothing points: 1 point Substrate analysis Calculation wavelength range: 300nm~800nm Atmosphere layer: Air ·Substrate layer:@N-CAU n-Cauchy Initial parameters (n-Cauchy) a=0.00000E+0,b=0.00000E+0,c=1.65000E+0

[0049] The refractive index at a wavelength of 550.0 nm, the refractive index at a wavelength of 589.0 nm, and the refractive index at a wavelength of 633.0 nm were respectively designated as d1, d2, and d3, and the tentative Abbe number Vd was calculated by the following formula (1). The obtained refractive indexes and tentative Abbe number Vd are shown in Table 1. Vd = (d2-1) / (d1-d3) (1)

[0050] [Measurement of reflection density of PET film alone] Using a Macbeth densitometer (product name: RD-918, manufactured by GretagMacbeth), the reflection density of the white and black parts of the attached standard reflector was measured on the opposite side of the sample piece to the part where the black masking tape was attached, after confirming that the values ​​were the specified values. The results are shown in Table 1.

[0051] [Laminated body production] The same commercially available MR-PET film and commercially available general PET film used in [Measurement of refractive index of PET film alone] were used as the substrate films to prepare laminates in the following procedure. A printed layer was formed on one side of the substrate film. An anchor coating agent containing a polyester-based polyurethane resin was applied to the printed layer to form a first anchor coating layer (AC1) with a thickness of 0.5 μm.

[0052] A polyethylene film (PE1, thickness: 15 μm) was attached onto the first anchor coat layer by extrusion lamination, and aluminum foil (thickness: 7 μm) was further vapor-deposited onto the polyethylene film. An anchor coating agent was applied onto the vapor-deposited aluminum foil to form a second anchor coat layer (AC2) with a thickness of 0.5 μm.

[0053] A polyethylene film (PE2, thickness: 25 μm) was bonded as a sealant layer on the prepared second anchor coat layer by extrusion lamination. In this way, a laminate was prepared. The laminate was cut at the same position as the position where the PET film alone was cut in [Measurement of refractive index of PET film alone] to obtain laminate sample pieces (10 cm x 10 cm) of each Example and each Comparative Example. The laminate sample piece including the PET film cut at the same position as the sample piece of the PET film alone in Example 1 was used as the laminate sample piece of Example 1. The same was true for Examples 2 to 20 and Comparative Examples 1 to 8. Therefore, the provisional Abbe number of the PET film included in the laminate sample piece of each Example can be regarded as the provisional Abbe number of the PET film alone of the same Example number. Also, the provisional Abbe number of the PET film included in the laminate sample piece of each Comparative Example can be regarded as the provisional Abbe number of the PET film alone of the same Comparative Example number.

[0054] The layer structure in each example is as follows. MR-PET film / printing layer / AC1 / adhesive layer / PE1 / aluminum foil / AC2 / adhesive layer / PE2

[0055] The layer configuration in each comparative example is as follows. General PET film / printing layer / AC1 / adhesive layer / PE1 / aluminum foil / AC2 / adhesive layer / PE2

[0056] [Measurement of reflection density of laminate] The reflection density of the surface on the substrate film side of the obtained sample piece was measured using a Macbeth densitometer (product name: RD-918, manufactured by GretagMacbeth Co., Ltd.) The results are shown in Table 1.

[0057] [Table 1]

[0058] As shown in Table 1, the tentative Abbe number Vd of the MR-PET film was smaller than that of the general PET film. Therefore, it was thought that the MR-PET film had a tendency to bleed on the surface more than the general PET film, which resulted in poor visibility. In addition, there was no difference in the reflection density of the PET film alone between the MR-PET film and the general PET film. However, when comparing the reflection density of the PET film when laminated, it was confirmed that the reflection density of the laminate using the MR-PET film was clearly higher than that of the laminate using the general PET film, and the surface was clearly visible. Therefore, when the recycled PET film, which was thought to have a low tentative Abbe number Vd and poor visibility when used alone, was laminated, the visibility of the surface was improved on the contrary. This showed that even if an MR-PET film with a low tentative Abbe number was used, a laminate with high visibility of the printed part, etc. could be obtained. Therefore, it was shown that it is possible to produce packaging bags and packaging bodies with high visibility using environmentally friendly recycled PET film. [Industrial Applicability]

[0059] According to the present disclosure, it is possible to provide a laminate that uses a recycled PET film and has a sufficiently high reflection density and improved visibility. The present disclosure also provides a packaging bag and a packaging body including such a laminate. [Explanation of symbols]

[0060] 10...base film, 20...intermediate layer, 30...sealant layer, 40...metal layer, 100, 101...laminate, S...adhesive layer, x...surface, 200...packaging bag, 211...sealed portion, 214...side end, 215...unsealed portion, 216...lower end, 217...upper end, 218...container portion, 220...opening means, 221...half-cut line, 224...easy-open processing portion, 230...resealing means.

Claims

1. A laminate comprising a base film and a sealant layer, The base film is a recycled polyethylene terephthalate film having a tentative Abbe number Vd of 24.0 to 40.0, calculated by the following formula (1) where d1 is the refractive index at a wavelength of 550.0 nm, d2 is the refractive index at a wavelength of 589.0 nm, and d3 is the refractive index at a wavelength of 633.0 nm. Vd=(d2-1) / (d1-d3) (1)

2. The laminate of claim 1 , wherein the recycled polyethylene terephthalate film is a mechanically recycled polyethylene terephthalate film.

3. The laminate according to claim 1, wherein the recycled polyethylene terephthalate film has a thickness of 9 to 100 μm.

4. The laminate according to any one of claims 1 to 3, wherein the reflection density of the surface of the laminate on the side of the base film is 0.19 to 0.

25.

5. A packaging bag comprising the laminate according to any one of claims 1 to 3.

6. A package comprising the packaging bag according to claim 5 and an item contained in the container of the packaging bag.

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