Laminate and method for manufacturing the same, packaging bag, and package

Abstract

To provide a laminate having sufficiently high sanitary properties, while using a film containing mechanically recycled polyethylene terephthalate.SOLUTION: A laminate 100 includes a base material film 10 and a sealant layer 30, wherein the base material film 10 is a film containing mechanically recycled polyethylene terephthalate, and when the film is sunk in ultrapure water at 100°C in a sealed container for 72 hours, an elution amount of antimony to the ultrapure water is 7.5 ng / cm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate, a method for manufacturing the same, a packaging bag, and a package. [Background technology]

[0002] Packaging bags comprising a laminate based on recycled polyethylene terephthalate (PET) film are environmentally friendly packaging bags, and their active use is expected. Known methods for recycling PET include mechanical recycling, in which PET is treated at high temperature and reduced pressure, and chemical recycling, in which PET is chemically decomposed. Patent Document 1 describes the use of a laminate using a resin film containing mechanically recycled PET for packaging bags. However, antimony derived from the catalyst used in the PET production process remains in the PET and affects the hygienic quality of the contents inside the packaging bag. Patent Document 2 discloses a polyester container containing chemically recycled polyester and with a reduced antimony content. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-015764 [Patent Document 2] Patent Publication No. 2021-187452 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a concern that recycled PET films produced through a recycling process may contain residual antimony, which was used in the synthesis of polyester. However, because the amount of antimony remaining in PET films is so small, it is difficult to quantify, making it difficult to evaluate the hygiene of recycled PET films. The present disclosure provides a laminate that uses a film containing mechanically recycled polyethylene terephthalate and yet has sufficiently high hygiene, a method for producing the same, and a packaging bag and packaging body that include such a laminate. [Means for solving the problem]

[0005] One aspect of the present disclosure is a laminate including a base film and a sealant layer, wherein the base film is a film containing mechanically recycled polyethylene terephthalate, and when the laminate is submerged in ultrapure water at 100°C for 72 hours in a sealed container, the amount of antimony eluted into the ultrapure water is 7.5 ng / cm 2 A laminate is provided, which is:

[0006] Although the laminate uses a film containing mechanically recycled polyethylene terephthalate (MR-PET film), the amount of antimony eluted into ultrapure water is small, and therefore the hygienic properties of the laminate can be improved.

[0007] One aspect of the present disclosure is a laminate including a base film and a sealant layer, wherein the base film is a film containing mechanically recycled polyethylene terephthalate, and when the base film is submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water is 43.0 ng / cm 2 A laminate is provided, which is:

[0008] The above laminate had an antimony elution rate of 43.0 ng / cm 2 The laminate includes the following MR-PET film: Since the amount of antimony eluted from the MR-PET film is small, the hygienic properties of the laminate can be improved.

[0009] One aspect of the present disclosure is a method for manufacturing a laminate comprising: laminating a base film and a sealant layer; and, in the lamination, the base film is immersed in ultrapure water at 100°C for 72 hours in a sealed container, and the amount of antimony eluted into the ultrapure water is 43.0 ng / cm. 2 A method for producing a laminate using a film containing mechanically recycled polyethylene terephthalate is provided.

[0010] The laminate obtained by the above-mentioned method for producing a laminate had an antimony elution amount of 43.0 ng / cm 3 when submerged in ultrapure water at 100°C for 72 hours in a sealed container. 2 The following MR-PET film is used as the base film: Since the amount of antimony eluted from the MR-PET film is small in this laminate, the hygiene of the laminate can be improved.

[0011] One aspect of the present disclosure provides a packaging bag including the laminate. The packaging bag includes the laminate, which can sufficiently suppress deterioration of the quality of the contents contained therein, thereby achieving sufficiently high hygiene.

[0012] One aspect of the present disclosure provides a package including the above-described packaging bag and an item to be contained in a container of the packaging bag. By including the above-described laminate, the package reduces the amount of antimony eluted into the item contained in the packaging bag, thereby sufficiently suppressing deterioration of the quality of the item. Therefore, the package is particularly suitable for use when the item requires high hygiene. [Effects of the Invention]

[0013] The present disclosure can provide a laminate that uses a film containing mechanically recycled polyethylene terephthalate and yet has sufficiently high hygiene, a method for manufacturing the same, and a packaging bag and a packaging body that include such a laminate. [Brief explanation of the drawings]

[0014] [Figure 1]FIG. 2 is a diagram showing an example of a cross section of a laminate. [Figure 2] FIG. 10 is a diagram showing another example of a cross section of a laminate. [Figure 3] FIG. 1 is a plan view showing an example of a packaging bag. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. The upper or lower limit of a numerical range specified in this disclosure may be replaced with any value shown in the examples. Furthermore, the upper and lower limit values ​​individually described may be arbitrarily combined. Unless otherwise specified, the materials or components exemplified in this disclosure may be used alone or in combination of two or more. In the description, identical elements or elements having the same function are denoted by the same reference numerals, and redundant description will be omitted. Furthermore, the positional relationships, such as up, down, left, and right, used in the description will be based on the positional relationships shown in the drawings unless otherwise specified.

[0016] 1 is a diagram showing an example of a cross section of a laminate according to the present disclosure. The laminate 100 has a sealant layer 30 on one side of a base film 10. An adhesive layer S is interposed between the base film 10 and the sealant layer 30.

[0017] The substrate film 10 is the outermost layer and is made of a film containing mechanically recycled polyethylene terephthalate (MR-PET film). MR-PET film can be obtained by crushing and cleaning polyethylene terephthalate (PET), treating it at high temperature and reduced pressure for a certain period of time, melt filtering to remove impurities, and then returning it to PET resin, which is then processed into a film. Using MR-PET film produced through such a recycling process as the substrate film 10 reduces the consumption of plastic resources and the CO2 emissions during PET production, resulting in an environmentally friendly laminate 100.

[0018] In addition to mechanically recycled polyethylene terephthalate, the base film 10 may contain virgin PET, which is PET newly synthesized from raw materials such as petroleum. The mass proportion of the mechanically recycled polyethylene terephthalate contained in the base film 10 may be 60% to 100% of the total mass of the base film 10.

[0019] The repeating units of PET include diol units and dicarboxylic acid units. The dicarboxylic acid units of mechanically recycled polyethylene terephthalate include terephthalic acid and isophthalic acid. That is, the base film 10 contains PET having dicarboxylic acid units containing terephthalic acid and isophthalic acid. The proportion of isophthalic acid in the total dicarboxylic acid units of the PET contained in the base film 10 may be 0.5 to 5 mol %.

[0020] The thickness of the base film 10 (MR-PET film) 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 desired properties. By setting the thickness to the above upper limit or less, it is possible to prevent a decrease in sealing performance during packaging and a decrease in the flexibility of the package. Furthermore, by setting the thickness to the above lower limit or more, it is possible to maintain sufficient stiffness as a package and to sufficiently prevent the occurrence of wrinkles and the like during packaging.

[0021] The MR-PET film may be a stretched film or an unstretched film. It is believed that the degree of crystal orientation within a polymer film is improved by stretching the film. Therefore, from the viewpoint of increasing the amount of oriented crystals within the film and improving puncture strength, it is preferable to use a stretched film. The stretching direction may be either the MD direction or the TD direction. Furthermore, the stretching method may be any method that can provide a dimensionally stable film, such as uniaxial stretching or biaxial stretching. It is preferable to use a biaxially stretched film as the MR-PET film from the viewpoint of further improving puncture strength.

[0022] When the laminate 100 was submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 7.5 ng / cm 2 The laminate 100 is excellent in hygiene because of the low content of antimony in the laminate 100. From the viewpoint of further improving the hygiene of the laminate, the amount of antimony eluted into ultrapure water is set to 7.4 ng / cm 2 or less, or 7.3 ng / cm 2 The amount of antimony eluted may be 6.0 ng / cm or less. 2 It may be more than that.

[0023] When an MR-PET film as the base film 10 was submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 43.0 ng / cm 2 The amount of antimony eluted from the base film 10 was 42.5 ng / cm 2 may be less than 41.5 ng / cm 2 may be less than 40.0 ng / cm 2 may be less than 37.5 ng / cm 2 may be less than 36.5 ng / cm 2 If the amount of eluted antimony is within this range, the MR-PET film has sufficiently high hygienic properties, and the hygienic properties of the laminate 100 can be further improved. From the viewpoint of availability, the amount of eluted antimony of the MR-PET film is preferably 30.0 ng / cm or less. 2 It may be more than that.

[0024] Because antimony is a catalyst used in the polymerization of PET, the concentration of antimony remaining in PET film varies even when PET film is manufactured under the same manufacturing conditions. Furthermore, recycled PET film is produced by blending PET film manufactured under multiple manufacturing conditions during the recycling process, which is likely to further increase the variation in the concentration of antimony remaining in recycled PET film. Therefore, even when MR-PET film is obtained from the same manufacturer, there will be variation between lots or between cut-out positions within the same lot. By eluting antimony from MR-PET film under the above elution conditions, it is possible to detect even minute amounts of antimony elution, making it possible to distinguish differences in the amount of antimony eluted between lots or between cut-out positions within the same lot, even when MR-PET film is manufactured under the same manufacturer.

[0025] The amount of antimony eluted can be determined by submerging the laminate 100, 101 or the MR-PET film in ultrapure water at 100°C in a sealed container for 72 hours, measuring the amount of antimony eluted into the ultrapure water by atomic absorption, and converting the absorbance obtained. The atomic absorption measurement device can be, for example, a furnace-type atomic absorption spectrophotometer (product name: ZA3700, manufactured by Hitachi High-Tech Science Corporation).

[0026] Antimony can be eluted in a constant temperature dryer set at 100°C. For example, the dryer can be a constant temperature dryer "DO-450A" (product name) manufactured by AS ONE Corporation. Ultrapure water with an electrical resistance of 18.2 MΩ cm or more at 25°C can be used.

[0027] The area of ​​the main surface of the laminated body 100, 101 is 20 to 100 cm 2 , 30~80cm 2 , or 40-60cm 2The area of ​​the main surface of the laminate 100, 101 may be within the above range, so that the amount of antimony eluted can be measured more accurately. Therefore, the laminate 100, 101 having a reduced antimony content can be obtained more easily, and the hygiene of the laminate 100, 101 can be further improved. The shape of the laminate 100, 101 is not particularly limited, and may be a polygon such as a triangle or a rectangle, or a shape with a curve. The shape of the laminate 100, 101 may be, for example, a rectangle of 10 cm x 5 cm.

[0028] 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 specific examples include polyolefin-based 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-based resins such as ethylene-(meth)acrylic acid copolymers; blend resins of polyethylene and polybutene; homopolypropylene resin (PP); propylene-ethylene random copolymers, propylene-ethylene block copolymers, and propylene-α-olefin copolymers; and the like. The sealant layer 30 may contain one of two or more of these thermoplastic resins alone or in combination.

[0029] 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.

[0030] The thickness of the sealant layer 30 is preferably adjusted depending on the mass of the contents, the shape of the packaging bag, etc. The thickness of the sealant layer 30 is preferably, for example, 10 to 100 μm.

[0031] 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 more firmly bonded together.

[0032] 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 laminate 100 can be easily recycled.

[0033] A printing layer can be provided on the surface of the base film 10 facing the sealant layer 30. The printing layer is provided in 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 taking into consideration printability on the film, design such as color tone, adhesion, safety as a food container, etc. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Of these printing methods, gravure printing is preferred from the standpoints of productivity and high-resolution images.

[0034] To improve the adhesion of the printed layer, the surface of the base film 10 on the side of the printed layer may be subjected to various pretreatments such as corona treatment, plasma treatment, and flame treatment, or a coating layer such as an easy-adhesion layer may be provided.

[0035] Fig. 2 is a diagram showing another example of a cross section of a laminate according to 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 content 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 production 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.

[0036] As shown in Fig. 2, a metal layer 40 may be laminated between the intermediate layer 20 and the sealant layer 30. Taking into consideration the manufacturing conditions, the metal layer 40 may be laminated between the base film 10 and the intermediate layer 20. By providing the laminate 101 with the metal layer 40, the puncture strength and gas barrier properties of the laminate can be improved. Alternatively, the metal layer 40 may be vapor-deposited on the intermediate layer 20 in advance.

[0037] 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 improved, 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. Examples of anchor coat agents that can be used include polyester-based polyurethane resins and polyether-based polyurethane resins. The thickness of the anchor coat layer is not particularly limited, but may be 0.1 to 1 μm or 0.3 to 0.5 μm.

[0038] The metal layer 40 can be made of a known metal foil, such as copper foil or aluminum foil. Aluminum foil is preferred for improving gas barrier properties and preventing transmission of visible light and ultraviolet light. 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 101 is improved. Therefore, even if foreign matter adheres to the base film 10 in a package including the laminate 101, the problem of the foreign matter penetrating beyond the base film 10 can be prevented. Furthermore, trace molecules such as antimony contained in the base film 10 can be prevented from penetrating beyond the base film 10. This prevents deterioration of the quality of the contents.

[0039] The puncture strength of the laminates 100, 101 can be measured based on "7.5 Puncture Strength Test" in JIS Z1707:2019 "General Rules for Food Packaging Plastic Films." Measurements can be performed, for example, using a Tensilon AD-7303 (manufactured by A&D Co., Ltd.) to pierce the laminates 100, 101 from the surface x on the substrate film 10 side toward the opposite side. The puncture strength of the laminates 100, 101 may be 8.5 N or more, or even 8.6 N or more. By using a laminate with such puncture strength, packaging bags and packages with high puncture strength can be obtained. Therefore, antimony is less likely to penetrate the interior, resulting in a package with even higher hygienic properties. The puncture strength of the laminates 100, 101 may be 10.0 N or less.

[0040] An example of a method for manufacturing the laminate 100 is described below. The first step involves applying an adhesive to one side of the substrate film 10 and laminating the sealant layer 30. Examples of lamination include dry lamination, in which a film-like sealant layer 30 made of the thermoplastic resin described above is bonded to the substrate film 10 using an adhesive such as a one-component curing or two-component curing urethane adhesive; non-solder dry lamination, in which a film-like sealant layer 30 is bonded to the substrate film 10 using a solvent-free adhesive; and extrusion lamination, in which the thermoplastic resin described above is heated and melted, extruded into a curtain shape, and bonded. The adhesive used to bond the sealant layer 30 to the substrate film 10 forms an adhesive layer S, as shown in FIG. 1 . Alternatively, the sealant layer 30 may be directly bonded to the substrate film 10 without the adhesive layer S.

[0041] Before applying the adhesive to the base film 10, an anchor coating agent may be applied to the base film 10 and dried, and then a printed layer may be formed. In this case, the adhesive is applied to the printed layer, and the sealant layer 30 is laminated and adhered.

[0042] When manufacturing the laminate 101, the sealant layer 30 is replaced with an intermediate layer 20, and the base film 10 and the intermediate layer 20 are laminated and bonded together. Furthermore, an anchor coating agent is applied to the surface of the intermediate layer 20, and after drying, a metal layer 40 is vapor-deposited. Thereafter, an adhesive is applied to the surface of the metal layer 40, and the sealant layer 30 is laminated and bonded together. In this manner, the laminate 101 can be manufactured.

[0043] A commercially available product can be used as the MR-PET film of the base film 10. When the MR-PET film used as the base film 10 is submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water is 43.0 ng / cm 2 The following MR-PET films are used:

[0044] The MR-PET film had an antimony elution rate of 42.5ng / cm 2The following may also be used: 41.5 ng / cm 2 The following may also be used: 40.0 ng / cm 2 The following may also be used: 37.5 ng / cm 2 The following may also be used: 36.5 ng / cm 2 The following may also be used: When the amount of antimony elution is within this range, the base film 10 has sufficiently high hygienic properties, and the hygienic properties of the laminates 100 and 101 can be improved. From the viewpoint of availability, the amount of antimony elution from MR-PET film is set to 30.0 ng / cm 2 The above may also be used.

[0045] By performing antimony elution using the above-described procedure, even if the MR-PET film is from a different lot but from the same manufacturer, slight differences in antimony concentration can be detected, and an MR-PET film with a low antimony concentration can be selected as the base film 10. Laminates made using such MR-PET films have sufficiently high hygienic properties.

[0046] The amount of antimony eluted can be determined by submerging the MR-PET film (substrate film 10) of the laminates 100, 101 in ultrapure water at 100°C in a sealed container for 72 hours, measuring the antimony eluted into the ultrapure water by atomic absorption, and converting the absorbance obtained. The atomic absorption measurement device can be, for example, a furnace-type atomic absorption spectrophotometer (product name: ZA3700, manufactured by Hitachi High-Tech Science Corporation).

[0047] Antimony can be eluted in a constant temperature dryer set at 100°C. The constant temperature and humidity dryer can be, for example, the DO-450A (trade name) manufactured by AS ONE Corporation. Ultrapure water with an electrical resistance of 18.2 MΩ cm or more at 25°C can be used.

[0048] 3 is a plan view showing an example of a packaging bag formed using a laminate. The packaging bag 200 includes a sealed portion 211 formed by bonding together the peripheral edges 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 side edges 214, a lower edge 216, and an upper edge 217 sealed by the sealed portion 211. The packaging bag 200 includes a storage portion 218 in an unsealed portion 215 surrounded by the sealed portion 211, in which an item such as food is stored. The item such as food is sealed in the storage portion 218. The sealed portion 211 at the lower edge 216 may be sealed after the item is filled into the storage portion 218.

[0049] The pair of laminates 100 are overlapped with each other so that the sealant layers 30 face each other. The pair of laminates 100 may be bonded to each other at a seal portion 211 with 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.

[0050] The laminate 100 has a low concentration of antimony and is therefore sufficiently hygienic. This sufficiently prevents antimony from penetrating into the packaging bag 200 through pinholes, thereby contaminating or deteriorating the contents contained in the storage section 218. The packaging bag 200 may have any layer provided on the base film 10 and the sealant layer 30 of the laminate 100.

[0051] 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 laminates 100, the sealant layers 30 of the laminates 100 are placed opposite each other, and the sealant layers 30 are bonded together with a fastener tape, for example, sandwiched therebetween, which serves as the resealing means 230. This forms sealed portions 211 at positions corresponding to the top end 217 and the side end portions 214, 214, and forms a non-sealed portion 215 surrounded by the sealed portions 211 in a U-shape.

[0052] After forming the sealed portion 211, the opening means 220 may be formed. For example, easy-open processed portions 224, 224 consisting of a group of scars are formed on the side end portions 214, 214. The easy-open processed portions 224 are not limited to a group of scars and may be V-, U-, or I-shaped notches. Furthermore, a half-cut line 221, which serves as a slit path from the easy-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 forming the opening means 220, the sealed portion 211 is cut and trimmed to separate the package into individual packaging bags.

[0053] 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.

[0054] 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 edges 214, 214 of the packaging bag 200 and across the gap between them to open it, and resealing means 230 below the opening means 220 for resealing the containing portion 218 after it has been opened by the opening means 220. The resealing means 230 can appropriately employ a known structure that allows repeated opening and sealing. For example, it may be a synthetic resin zipper that allows repeated sealing by fitting a strip-shaped protrusion into a strip-shaped groove, or an adhesive seal.

[0055] The package includes a packaging bag 200 and an item contained in the container 218 of the packaging bag 200. Examples of the item include food, electronic components, and electronic devices. Because the package includes the packaging bag 200, the package contains a low amount of antimony, and this prevents the contents from being altered or deteriorated due to the intrusion of trace components such as antimony, low-molecular-weight components, PET components, or outside air through pinholes created by puncturing. Furthermore, because recycled PET can be used as the packaging bag, it is possible to provide an environmentally friendly and sufficiently hygienic package.

[0056] 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 laminate 101 used in the above description may be interchangeable as appropriate. The laminates 100 and 101 may include 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 functionality 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, they may be two-sided bags, three-sided bags, or palm-shaped bags, or they may be standing pouches with bottom tape added.

[0057] The present disclosure includes the following embodiments. [1] A laminate comprising a base film and a sealant layer, the base film is a film containing mechanically recycled polyethylene terephthalate, When submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony dissolved into the ultrapure water was 7.5ng / cm 2 The laminate is as follows: [2] A laminate comprising a base film and a sealant layer, the base film is a film containing mechanically recycled polyethylene terephthalate, When the base film was submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 43.0ng / cm2 The laminate is as follows: [3] The laminate according to [1] or [2], having a puncture strength of 8.5 N or more. [4] A packaging bag comprising the laminate described in [1] or [2] above. [5] A package comprising the packaging bag described in [4] above and an item to be contained in the storage section of the packaging bag. [6] A method for producing a laminate, comprising a step of laminating a base film and a sealant layer, When the base film was submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 43.0ng / cm 2 A method for producing a laminate using a film containing the following mechanically recycled polyethylene terephthalate. [7] The laminate obtained in the above step has an antimony elution amount of 7.5 ng / cm when submerged in ultrapure water at 100°C in a sealed container for 72 hours. 2 The method for producing a laminate according to [6], which is as follows: [Example]

[0058] The present disclosure will be described in more detail below with reference to examples, comparative examples, and reference examples. However, the present disclosure is not limited to the following examples.

[0059] [Preparing the base film] A commercially available film containing mechanically recycled PET (MR-PET film) and a commercially available PET film (ordinary PET film) that had not undergone a recycling process were prepared.

[0060] Three types of MR-PET film were prepared from the same manufacturer but different lots, designated MR-PET film A, MR-PET film B, and MR-PET film C. Similarly, three types of general PET film were prepared from the same manufacturer but different lots, designated General PET film A, General PET film B, and General PET film C. In addition, General PET film D was prepared from a different manufacturer than General PET film A, General PET film B, and General PET film C. The thickness of each PET film was 12 μm.

[0061] [Measurement of the amount of antimony eluted from each PET film] Each PET film was cut into a 10 cm x 5 cm piece, and the cut PET film was then divided into six pieces measuring approximately 2 cm x 3.3 cm. 25 mL of ultrapure water was placed in a sealed container (heat-resistant temperature 120°C), and the six pieces of PET film were submerged in the ultrapure water. The sealed container was then placed in a constant temperature dryer (AS ONE Corporation, product name: DO-450A) set to 100°C and left to stand for 72 hours, allowing the antimony to dissolve into the ultrapure water.

[0062] The solution was then diluted 10 times with ultrapure water to prepare a test solution, and the absorbance of antimony was measured using an atomic absorption spectrophotometer (manufactured by Hitachi High-Tech Science Corporation, product name: ZA3700). The absorbance was converted to the concentration (ng / mL) in the test solution using a calibration curve of known concentrations. The converted antimony concentration in the test solution was calculated using the following equation (1) based on the area (cm) of the PET film. 2 ) elution amount (ng / cm 2 The amount of elution per area (ng / cm 2 ) was taken as the amount of antimony dissolved into ultrapure water.

[0063] Amount of antimony dissolved per area (ng / cm 2 ) = Antimony concentration in the measurement solution (ng / mL) × Volume of ultrapure water (mL) × Dilution ratio / Area of ​​PET film (cm 2 ) (1)

[0064] Two measurement samples (n=2) of each of MR-PET Film A, General PET Film A, and General PET Film D were prepared, and the amount of antimony eluted into ultrapure water for each sample was measured. Three measurement samples (n=3) of each of MR-PET Film C and General PET Film C were prepared, and the amount of antimony eluted into ultrapure water for each sample was measured. Meanwhile, six measurement samples (n=6) of each of MR-PET Film B and General PET Film B were prepared, and the amount of antimony eluted into ultrapure water for each sample was measured. The results are shown in Table 1.

[0065] [Laminate fabrication] Example 1 A laminate was produced using MR-PET film A as the base film using the following procedure. A printed layer was formed on one side of the base film. An anchor coating agent containing a polyester-based polyurethane resin was applied to the printed layer to form a 0.5 μm-thick first anchor coating layer (AC1).

[0066] A polyethylene film (PE1, thickness: 15 μm) was bonded onto the first anchor coat layer using the extrusion lamination method, and aluminum foil (thickness: 7 μm) was then vapor-deposited onto the polyethylene film. An anchor coating agent was applied to the vapor-deposited aluminum foil to form a second anchor coat layer (AC2) with a thickness of 0.5 μm.

[0067] A polyethylene film (PE2, thickness: 25 μm) was bonded as a sealant layer onto the prepared second anchor coat layer by extrusion lamination. In this way, a laminate was prepared. The prepared laminate was cut into 4.8 cm × 4.8 cm sample pieces.

[0068] The layer structure of the laminate of this example is as follows. PE2 / adhesive layer / AC2 / aluminum foil / PE1 / adhesive layer / AC1 / printing layer / MR-PET film A

[0069] Example 2 Instead of MR-PET film A, MR-PET film C was used, and the antimony elution concentration was 43.0 ng / cm 2 A laminate of Example 2 was produced in the same manner as in Example 1, except that the following was used as the base film.

[0070] (Comparative Example 1) A laminate of Comparative Example 1 was produced in the same manner as in Example 1, except that MR-PET film B was used as the base film instead of MR-PET film A. The produced laminate was cut into sample pieces measuring 4.8 cm × 4.8 cm.

[0071] The layer structure of the laminate of Comparative Example 1 is as follows. PE2 / adhesive layer / AC2 / aluminum foil / PE1 / adhesive layer / AC1 / printing layer / MR-PET film B

[0072] (Comparative Example 2) Instead of MR-PET film A, MR-PET film C was used, and the antimony elution concentration was 43.0 ng / cm 2 The laminate of Example 2 was produced in the same manner as in Example 1, except that a larger substrate film was used.

[0073] (Reference example 1) A laminate of Reference Example 1 was produced in the same manner as in Example 1, except that ordinary PET film A was used as the base film instead of MR-PET film A. The produced laminate was cut into sample pieces of 4.8 cm × 4.8 cm.

[0074] (Reference example 2) A laminate of Reference Example 2 was produced in the same manner as in Example 1, except that ordinary PET film B was used as the base film instead of MR-PET film A. The produced laminate was cut into 4.8 cm × 4.8 cm sample pieces.

[0075] (Reference example 3) A laminate of Reference Example 3 was produced in the same manner as in Example 1, except that ordinary PET film C was used as the base film instead of MR-PET film A.

[0076] (Reference example 4) A laminate of Reference Example 4 was produced in the same manner as in Example 1, except that ordinary PET film D was used as the base film instead of MR-PET film A. The produced laminate was cut into 4.8 cm × 4.8 cm sample pieces.

[0077] [Measurement of puncture strength of laminated body] The puncture strength of the surface x of the base film 10 of the sample pieces of Example 1, Comparative Example 1, Reference Example 1, Reference Example 2, and Reference Example 4 was measured based on "7.5 Puncture Strength Test" of JIS Z1707:2019 "General Rules for Plastic Films for Food Packaging." The measuring device used was a Tensilon AD-7703 (manufactured by A&D Co., Ltd.). The puncture strength was measured under the following conditions. The measurement results are shown in Table 1. In Table 1, portions for which no measurement was performed are indicated by "-."

[0078] Test speed: 50mm / min Load cell: 100N Load range: 20N (20%)

[0079] [Measurement of the amount of antimony eluted from laminates] The laminates of Example 2, Comparative Example 2, and Reference Example 3 were cut into 10 cm x 5 cm pieces, and the cut-out laminates were divided into six pieces each measuring approximately 2 cm x 3.3 cm. 25 mL of ultrapure water was placed in a sealed container (heat-resistant temperature 120°C), and the six pieces of the laminate were submerged in the ultrapure water. The sealed container was then placed in a constant temperature dryer (AS ONE Corporation, product name: DO-450A) set at 100°C and left to stand for 72 hours, allowing antimony to dissolve into the ultrapure water.

[0080] The solution was then diluted 1.25 times with ultrapure water to prepare a test solution, and the absorbance of antimony was measured using an atomic absorption spectrophotometer (manufactured by Hitachi High-Tech Science Corporation, product name: ZA3700). The absorbance was converted to the concentration (ng / mL) in the test solution using a calibration curve of known concentrations. The converted antimony concentration in the test solution was then calculated using the following equation (1) to calculate the antimony concentration in the test solution relative to the area (cm) of the PET film. 2 ) elution amount (ng / cm 2 The amount of elution per area (ng / cm 2 The results are shown in Table 1.

[0081] Amount of antimony dissolved per area (ng / cm 2 ) = Antimony concentration in the measurement solution (ng / mL) × Volume of ultrapure water (mL) × Dilution ratio / Area of ​​PET film (cm 2 ) (1)

[0082] [Table 1]

[0083] As shown in Table 1, MR-PET Film A had a lower amount of antimony elution than MR-PET Film B. This indicates that a laminate can be produced by selecting an MR-PET film with a low amount of antimony elution, even when produced by the same manufacturer. It was also confirmed that MR-PET Film C had high and low antimony concentrations depending on the cut portion. This indicates that a laminate can be produced by selecting a portion with a low amount of antimony elution, even when produced from the same lot. A comparison of Example 2 and Comparative Example 2 revealed a correlation between the amount of antimony elution from the substrate film and the amount of antimony elution from the laminate. This indicates that a laminate with sufficiently high hygienic properties can be obtained by selecting an MR-PET film with a low amount of antimony elution and using it as the substrate film for the laminate. Furthermore, the puncture strength of the laminate was sufficiently high, indicating that a laminate with low pinhole formation could be produced. [Industrial Applicability]

[0084] According to the present disclosure, it is possible to provide a laminate that uses a film containing mechanically recycled PET and yet has sufficiently high hygiene, a method for manufacturing the same, and a packaging bag and packaging body that include such a laminate. [Explanation of symbols]

[0085] 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 edge, 215...unsealed portion, 216...lower end, 217...upper end, 218...storage 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 film containing mechanically recycled polyethylene terephthalate, When submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 7.5 ng / cm ２ The laminate is as follows:

2. A laminate comprising a base film and a sealant layer, the base film is a film containing mechanically recycled polyethylene terephthalate, When the substrate film was submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 43.0 ng / cm ２ The laminate is as follows:

3. The laminate according to claim 1 or 2, which has a puncture strength of 8.5 N or more.

4. A packaging bag comprising the laminate according to claim 1 or 2.

5. A package comprising the packaging bag according to claim 4 and an item to be contained in the container of the packaging bag.

6. A method for producing a laminate, comprising a step of laminating a base film and a sealant layer, When the base film was submerged in ultrapure water at 100°C in a sealed container for 72 hours, the amount of antimony eluted into the ultrapure water was 43.0 ng / cm ２ A method for producing a laminate using a film containing the following mechanically recycled polyethylene terephthalate.

7. The laminate obtained in the above step had an antimony elution amount of 7.5 ng / cm3 when submerged in ultrapure water at 100°C in a sealed container for 72 hours. ２ The method for producing a laminate according to claim 6, wherein:

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