Methods for recovering laminates, packaging, and plastics

Abstract

The present invention provides a laminate, packaging, and method for recovering plastic substrates that can be separated and recovered without using a basic aqueous solution. [Solution] The laminate (1) is provided with a strongly bonded region (21) where the first plastic substrate layer (10) and the second plastic substrate layer (12) are joined, and a weakly bonded region (22) and / or a non-bonded region (23) adjacent to the strongly bonded region (21). The weakly bonded region (22) is a region where the bonding strength between the first plastic substrate layer (10) and the second plastic substrate layer (12) is lower than that of the strongly bonded region (21). The non-bonded region (23) is a region where the first plastic substrate layer (10) and the second plastic substrate layer (12) are not joined.

Description

[Technical Field]

[0001] The present disclosure relates to a laminate, a package, and a method for recovering plastics. [Background Art]

[0002] Conventionally, plastic packages such as pouches and pillow packages have been used in various fields including the food field and toiletries. Plastic packages such as pouches and pillow packages are generally formed of a laminate including a plastic base material layer and a sealant layer adhered to the entire surface of the plastic base material layer.

[0003] In recent years, the problem of plastic waste caused by discarded plastic products flowing out into the ocean through rivers and the like has attracted attention. Plastic waste may drift in the ocean and cause adverse effects on the natural environment.

[0004] As a method for reducing such plastic waste, for example, Patent Document 1 and Patent Document 2 disclose a method for producing a recyclable base material, in which a laminate including a plastic base material and a release layer containing an inorganic substance soluble in a basic aqueous solution and / or a resin is immersed in a basic aqueous solution to dissolve the release layer, thereby enabling recovery of the plastic base material. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 2020-175620 [Patent Document 2] Japanese Unexamined Patent Publication No. 2021-098295 [Summary of the Invention] [Problem to be Solved by the Invention]

[0006] However, the method for producing recyclable substrates that can recover plastic substrates using a basic aqueous solution described in Patent Documents 1 and 2 had the following problems. (a) It takes time for the desorption layer to dissolve in the basic aqueous solution. (b) If the desorption layer dissolves in a basic aqueous solution, the basic aqueous solution will become contaminated. (c) The desorption layer itself cannot be separated. (d) In order to remove the basic aqueous solution adhering to the recovered recycled substrate, it is necessary to wash the recycled substrate with a cleaning solution.

[0007] In view of the above circumstances, the object of this disclosure is to provide laminates, packaging materials, and a method for recovering plastic substrates that can separate and recover plastic substrates without using a basic aqueous solution. [Means for solving the problem]

[0008] The present disclosure relates to a laminate comprising a first plastic substrate layer and a second plastic substrate layer bonded to the first plastic substrate layer, wherein the laminate is provided with a strongly bonded region where the first plastic substrate layer and the second plastic substrate layer are bonded, and a weakly bonded region and / or a non-bonded region adjacent to the strongly bonded region, the weakly bonded region being a region where the bonding strength between the first plastic substrate layer and the second plastic substrate layer is lower than that of the strongly bonded region, and the non-bonded region being a region where the first plastic substrate layer and the second plastic substrate layer are not bonded.

[0009] This disclosure relates to a packaging comprising the above-described laminates, wherein the packaging has a sealed portion where the laminates are sealed to each other and an unsealed portion where the laminates are not sealed to each other, and the weakly bonded region and / or unsealed region are located in the unsealed portion.

[0010] This disclosure is a method for recovering a second plastic substrate layer from the above-mentioned packaging, comprising the steps of: producing plastic fragments by crushing the packaging; and separating the second plastic substrate layer from the plastic fragments without using an aqueous basic solution. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide laminates, packaging materials, and methods for recovering plastic substrates that can be separated and recovered without using a basic aqueous solution. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view of an example of the laminate according to Embodiment 1. [Figure 2] Figure 1 is a schematic plan view of an example of a laminate as seen from the second plastic substrate layer side. [Figure 3] This is a schematic plan view of a pouch, which is an example of a packaging body according to Embodiment 1. [Figure 4] This is an example of a schematic cross-section along line IV-IV in Figure 3. [Figure 5] This is a flowchart of an example of a plastic recovery method according to Embodiment 1. [Figure 6] This is a schematic cross-sectional view of an example of the laminate according to Embodiment 2. [Figure 7] This is a schematic cross-sectional view of an example of the laminate according to Embodiment 3. [Figure 8] This is a schematic cross-sectional view of an example of the laminate according to Embodiment 4. [Figure 9] This is a schematic perspective view of a pillow packaging, which is another example of the packaging of Embodiment 5. [Figure 10] This is a flowchart of an example of a plastic recovery method according to Embodiment 6. [Modes for carrying out the invention]

[0013] Embodiments will be described below. In the drawings used for describing the embodiments, the same reference numerals represent the same or corresponding parts.

[0014] [Embodiment 1] <Laminate> FIG. 1 shows a schematic cross-sectional view of an example of the laminate 1 according to Embodiment 1. As shown in FIG. 1, the laminate 1 according to Embodiment 1 includes a first plastic base material layer 10 and a second plastic base material layer 12 joined to the first plastic base material layer 10. The first plastic base material layer 10 includes, from the second plastic base material layer 12 side, a 1-1st plastic base material layer 11, a vapor deposition layer 14, a design printing layer 15, and a 1-2nd plastic base material layer 13.

[0015] The 1-1st plastic base material layer 11 and the 1-2nd plastic base material layer 13 may each be, for example, a polyethylene terephthalate resin film (hereinafter referred to as "PET film"), a nylon resin film (hereinafter referred to as "Ny film"), or the like.

[0016] The second plastic base material layer 12 may be, for example, a linear low-density polyethylene resin film (hereinafter referred to as "LLDPE film"), a biaxially oriented polypropylene resin film (hereinafter referred to as "OPP film"), an unstretched polypropylene resin film (hereinafter referred to as "CPP film"), or the like.

[0017] The vapor deposition layer 14 may be, for example, a vapor deposition layer of inorganic particles such as aluminum or silica. Although the vapor deposition layer 14 is not a plastic layer, even if the first plastic base material layer 10 includes the vapor deposition layer 14, it is expressed as "the first plastic base material layer 10".

[0018] The design printing layer 15 may be, for example, an ink layer on which letters and / or designs are inscribed using oil-based or water-based ink. When the laminate 1 includes the design printing layer 15, the accuracy of separating the second plastic substrate layer 12 in the process of separating the second plastic substrate layer 12, described later, can be improved by using a conventionally known optical sorter (a machine capable of sorting based on the presence or absence of coloring). Typically, the design printing layer 15 contained in the first plastic substrate layer 10 is colored, while the second plastic substrate layer 12 is colorless and transparent. Therefore, in the process of separating the second plastic substrate layer 12, described later, the accuracy of separating the second plastic substrate layer 12 can be improved by selectively removing the first plastic substrate layer 10 remaining after immersion of the plastic pieces in water using an optical sorter.

[0019] In the laminate 1 of Embodiment 1 shown in Figure 1, the first plastic substrate layer 10 and the second plastic substrate layer 12 are joined with a relatively high adhesive strength by the adhesive layer 16 in the strong bonding region 21, but are joined with a lower adhesive strength than in the strong bonding region 21 by the adhesion inhibiting layer 17 in the weak bonding region 22. In the strong bonding region 21, the first plastic substrate layer 10 and the second plastic substrate layer 12 are strongly bonded and cannot be easily separated, but in the weak bonding region 22, the first plastic substrate layer 10 and the second plastic substrate layer 12 maintain a state similar to pseudo-adhesion and can be separated relatively easily. The bonding strength between the first plastic substrate layer 10 and the second plastic substrate layer 12 in the strong bonding region 21 can be, for example, about 3 to 20 N / mm, and the bonding strength between the first plastic substrate layer 10 and the second plastic substrate layer 12 in the weak bonding region 22 can be, for example, about 0.1 to 0.8 N / mm.

[0020] As shown in the schematic plan view of Figure 2, when the laminate 1 of Embodiment 1 shown in Figure 1 is viewed from a plan view, for example, from the side of the second plastic substrate layer 12, the adhesive layer 16 is located in the strong bonding region 21 of the laminate 1, and the adhesion inhibiting layer 17 is located in the weak bonding region 22 of the laminate 1, as shown in Figure 1. In this disclosure, the strong bonding region 21 and the weak bonding region 22 each refer to the entire region in the lamination direction of the laminate 1. In the laminate 1, the weak bonding region 22 is adjacent to the strong bonding region 21. Note that in Figure 2, the dashed line 20 indicating the boundary between the adhesive layer 16 and the adhesion inhibiting layer 17 is a virtual line and is almost never visible in reality.

[0021] As the adhesive layer 16, for example, a layer using a conventionally known adhesive used for bonding resin films can be used as appropriate. As the adhesion inhibiting layer 17, a layer can be used that causes the bonding strength between the first plastic substrate layer 10 and the second plastic substrate layer 12 to be weaker than the bonding strength in the strong bonding region 21. As the adhesion inhibiting layer 17, for example, a layer using a conventionally known lamination inhibitor such as a release ink can be used as appropriate. Alternatively, as the adhesion inhibiting layer 17, for example, a layer made of a water-soluble adhesive used in the process of separating the second plastic substrate layer 12, as described later, can also be used.

[0022] It is preferable that the overall specific gravity of the laminate 1 is 1 or greater, the specific gravity of the first plastic substrate layer 10 is 1 or greater, and the specific gravity of the second plastic substrate layer 12 is less than 1. In this case, in the step of separating the second plastic substrate layer 12 described later, the first plastic substrate layer 10 will sink in the water and the second plastic substrate layer 12 will float on the water surface, making it easier to separate the second plastic substrate layer 12 from the laminate 1.

[0023] Furthermore, as shown in Figure 2, when the laminate 1 is viewed from the second plastic substrate layer 12 side, the area of ​​the strong bonding region 21 is preferably 35% or less of the total area of ​​the laminate 1, more preferably 30% or less, and even more preferably 20% or less. In this case, the amount of the second plastic substrate layer 12 that can be separated and recovered in the plastic recovery method described later can be increased. That is, the second plastic substrate layer 12 in the strong bonding region 21 cannot be separated and recovered, but the second plastic substrate layer 12 in the weak bonding region 22 can be separated and recovered. Note that in the example of the plan view of the laminate 1 shown in Figure 2, the area of ​​the strong bonding region 21 means the sum of the area of ​​the strong bonding region 21 on the left and the area of ​​the strong bonding region 21 on the right. Also, it goes without saying that in the example of the plan view of the laminate 1 shown in Figure 2, the total area of ​​the laminate 1 means the sum of the total area of ​​the strong bonding regions 21 on both the left and right sides and the area of ​​the weak bonding region 22 between them.

[0024] <Method for manufacturing laminates> The laminate 1 of Embodiment 1 can be manufactured, for example, as follows. First, a first-first plastic raw material roll is prepared, on which the first-first plastic resin film constituting the first-first plastic substrate layer 11 is wound; a first-second plastic raw material roll is prepared, on which the first-second plastic resin film constituting the first-second plastic substrate layer 13 is wound; and a second plastic raw material roll is prepared, on which the second plastic resin film constituting the second plastic substrate layer 12 is wound.

[0025] Next, while pulling out the first-1 plastic resin film from the first-1 plastic raw material roll, inorganic particles such as aluminum are deposited onto one surface of the first-1 plastic resin film to form a vapor-deposited layer 14, and an adhesion-inhibiting layer 17 is printed onto the other surface, and then the film is wound into a roll again to produce the first-1 plastic raw material roll with a vapor-deposited layer, which comprises the first-1 plastic substrate layer 11, the vapor-deposited layer 14, and the adhesion-inhibiting layer 17.

[0026] Furthermore, while pulling out the first-second plastic resin film from the first-second plastic raw material roll, a design printing layer 15 is formed by printing characters and / or designs on one surface of the first-second plastic resin film with oil-based or water-based ink, and then winding it back into a roll shape, thereby producing a first-second plastic raw material roll with a design printing layer, comprising the first-second plastic base material layer 13 and the design printing layer 15.

[0027] Next, the first plastic resin film is pulled out from the first plastic raw material roll with the vapor deposition layer, and the first plastic substrate layer 13 is pulled out from the first plastic raw material roll with the design printing layer, and after laminating these while applying adhesive so that the vapor deposition layer 14 of the first plastic resin film and the design printing layer 15 of the first plastic substrate layer 13 are bonded together, the roll is wound up again to produce the first plastic raw material roll in which the laminated film constituting the first plastic substrate layer 10 is wound up.

[0028] Finally, while pulling out the second plastic resin film constituting the second plastic base material layer 12 from the second plastic raw material roll, the adhesive constituting the adhesive layer 16 is applied to the entire surface of one side of the second plastic resin film, and these are laminated together with the surface of the first plastic raw material roll made as described above on the side with the adhesion inhibiting layer 17, and then wound into a roll again. In this way, a raw material roll made of laminated film constituting the laminate 1 of Embodiment 1 can be manufactured.

[0029] <Package> Figure 3 shows a schematic plan view of a pouch 100, which is an example of a packaging body according to Embodiment 1. As shown in Figure 3, the pouch 100 includes the laminate 1 of Embodiment 1 described above and a spout 103 attached to the top of the laminate 1. The pouch 100 also has a sealed portion 102, which is the part where the two laminates 1 are heat-sealed and welded together, and an unsealed portion 101, which is the part where the two laminates 1 are not heat-sealed and not welded together. Contents can be contained in the unsealed portion 101 of the pouch 100, and the sealed portion 102 surrounding the periphery of the unsealed portion 101 can prevent the contents from leaking out. In addition, the contents can be removed from the pouch 100 through the spout 103. The bonding strength of the laminates 1 in the sealed portion 102 can be, for example, about 3 to 20 N / mm.

[0030] Figure 4 shows an example of a schematic cross-section along line IV-IV in Figure 3. As shown in Figure 4, the pouch 100 comprises an upper first laminate 1a and a lower second laminate 1b. The first laminate 1a and the second laminate 1b each have a laminate structure similar to the laminate 1 of Embodiment 1 described above. The pouch 100 has a sealed portion 102 where the first laminate 1a and the second laminate 1b are heat-sealed and welded to each other, and an unsealed portion 101 where the first laminate 1a and the second laminate 1b are not heat-sealed and are not welded to each other. The weakly bonded regions 22 of the first laminate 1a and the second laminate 1b are located in the unsealed portion 101 of the pouch 100. The strongly bonded regions 21 of the first laminate 1a and the second laminate 1b are located in the sealed portion 102 of the pouch 100. In this disclosure, the non-seal portion 101 and the seal portion 102 refer to the regions of the pouch 100 in the stacking direction of the first laminate 1a and the second laminate 1b that constitute the pouch 100, respectively. In the pouch 100, the non-seal portion 101 is adjacent to the seal portion 102.

[0031] <Methods for collecting plastic> Figure 5 shows a flowchart of an example of the plastic recovery method of Embodiment 1. Here, we will describe a method for separating the second plastic substrate layer 12 from the pouch 100 shown in Figure 3, which is an example of the packaging of Embodiment 1 described above. In the plastic recovery method of Embodiment 1, first, a step S1001 for producing plastic fragments is performed. The step S1001 for producing plastic fragments can be performed, for example, by crushing the pouch 100 into small pieces using a conventionally known crusher. In step S1001, the crushing of the pouch 100 may be performed while washing the pouch 100 and the plastic fragments.

[0032] Next, step S1002 is performed to separate the second plastic substrate layer 12. Step S1002 for separating the second plastic substrate layer 12 can be performed, for example, by immersing the plastic pieces produced in step S1001 in water and stirring as necessary to separate the second plastic substrate layer 12 from the plastic pieces. It is preferable that the water in which the plastic pieces are immersed in step S1002 contains a surfactant. In this case, the first plastic substrate layer 10, which has a specific gravity of 1 or more, will settle in the water, and the second plastic substrate layer 12, which has a specific gravity of less than 1, will tend to float on the water surface, making it easier to separate the second plastic substrate layer 12. As the surfactant, for example, conventionally known surfactants can be used.

[0033] <Mechanism of separation of the second plastic substrate layer> When the plastic fragments produced by the crushing of the pouch 100 are composed of the unsealed portion 101 of the pouch 100, these plastic fragments will be composed of the weakly bonded region 22 of either the first laminate 1a or the second laminate 1b shown in Figure 4. This is because, in the unsealed portion 101 of the pouch 100, the first laminate 1a and the second laminate 1b are not welded together by heat sealing, and therefore, the crushing of the pouch 100 separates the first laminate 1a and the second laminate 1b.

[0034] Furthermore, the unsealed portion 101 of the pouch 100 is composed of a weak bonding region 22 of the first laminate 1a or the second laminate 1b. Therefore, when a small piece of plastic composed of the weak bonding region 22 of the first laminate 1a or the second laminate 1b is immersed in water and stirred as necessary, the bonding strength between the first plastic substrate layer 10 and the second plastic substrate layer 12 is low, allowing the second plastic substrate layer 12 to be easily separated and recovered from the first laminate 1a or the second laminate 1b. Thus, this disclosure provides a laminate, packaging, and method for recovering a plastic substrate that can separate and recover the plastic substrate (second plastic substrate layer 12) without using a basic aqueous solution. In this disclosure, if the plastic fragments consist of the sealed portion 102 of the pouch 100, the second plastic substrate layer 12 cannot be separated and recovered. However, if the plastic fragments are monomaterial without a thermal history from the unsealed portion 101 of the pouch 100, the second plastic substrate layer 12 can be recovered, which is considered useful. Furthermore, the recovered second plastic substrate layer 12 is suitable for recycling, is environmentally friendly as it does not use a basic aqueous solution, and is considered highly safe.

[0035] In particular, if the specific gravity of the laminate 1 of Embodiment 1 (the first laminate 1a or the second laminate 1b) is 1 or greater, the specific gravity of the first plastic substrate layer 10 is 1 or greater, and the specific gravity of the second plastic substrate layer 12 is less than 1, then when the plastic pieces are immersed in water, the first plastic substrate layer 10 will sink in the water and the second plastic substrate layer 12 will float on the water surface, making it easier to separate the second plastic substrate layer 12.

[0036] Furthermore, as shown in Figure 2, when the laminate 1 of Embodiment 1 is viewed from the second plastic substrate layer 12 side in a plan view, if the area of ​​the strongly bonded region 21 is 20% or less of the total area of ​​the laminate 1, the area of ​​the weakly bonded region 22 occupying the laminate 1 becomes relatively larger compared to the area of ​​the strongly bonded region 21. Therefore, in this disclosure, it becomes possible to separate and recover a larger amount of the second plastic substrate layer 12.

[0037] [Embodiment 2] Figure 6 shows a schematic cross-sectional view of an example of the laminate 1 of Embodiment 2. The laminate 1 of Embodiment 2 shown in Figure 6 is characterized by having a non-bonding region 23 between the first plastic substrate layer 10 and the second plastic substrate layer 12, instead of the weak bonding region 22 of the laminate 1 of Embodiment 1. The non-bonding region 23 is the region where the first plastic substrate layer 10 and the second plastic substrate layer 12 are not bonded. That is, the non-bonding region 23 of the laminate 1 of Embodiment 2 does not necessarily include other layers such as an adhesive layer 16 or an adhesion inhibiting layer 17 between the first plastic substrate layer 10 and the second plastic substrate layer 12. Therefore, when using the laminate 1 of Embodiment 2 shown in Figure 6, it becomes possible to separate the second plastic substrate layer 12 more easily than when using the laminate 1 shown in Figure 1. The description of Embodiment 2 other than those described above is the same as that of Embodiment 1, so the description is omitted here.

[0038] [Embodiment 3] Figure 7 shows a schematic cross-sectional view of an example of the laminate 1 of Embodiment 3. The laminate 1 of Embodiment 3 shown in Figure 7 is characterized in that the lamination structure of the first plastic substrate layer 10 differs from that of the laminate 1 of Embodiment 1. That is, in the first plastic substrate layer 10 of the laminate 1 of Embodiment 3 shown in Figure 7, the 1-1 plastic substrate layer 11, the vapor deposition layer 14, the 1-2 plastic substrate layer 13, the design printing layer 15, and the 1-3 plastic substrate layer 19 are laminated in this order from the side of the second plastic substrate layer 12. The 1-3 plastic substrate layer 19 may be, for example, a PET film or a Ny film. The laminate 1 of Embodiment 3 is useful in that, after the 1-1 plastic substrate layer 11 and the 1-2 plastic substrate layer 13 are bonded together with the vapor deposition layer 14 in between, the design printing layer 15 and the adhesion inhibiting layer 17 can be formed by double-sided printing. The description of Embodiment 3, other than that stated above, is the same as that of Embodiment 1, so that description will be omitted here.

[0039] [Embodiment 4] Figure 8 shows a schematic cross-sectional view of an example of the laminate 1 of Embodiment 4. The laminate 1 of Embodiment 4 shown in Figure 8 differs from the laminate 1 of Embodiment 3 shown in Figure 7 in that it does not have a design printing layer 15. The rest of the description of Embodiment 4 is the same as that of Embodiment 3, so that description is omitted here.

[0040] [Embodiment 5] Figure 9 shows a schematic perspective view of a pillow packaging 200, which is another example of the packaging of Embodiment 5. The pillow packaging 200 shown in Figure 9 comprises first sealing portions 102a at both ends of the pillow packaging 200 and second sealing portions 102b extending between the first sealing portions 102a at both ends in a direction different from that of the first sealing portions 102a at both ends. The area of ​​the pillow packaging 200 other than the first sealing portions 102a and the second sealing portions 102b is composed of a non-sealed portion 101. The pillow packaging 200 shown in Figure 9 can be manufactured, for example, by heat-sealing the second plastic base material layers 12 of the strong bonding regions 21 at both ends of any one of the laminates 1 of Embodiments 1 to 4 to form a second seal portion 102b and make it cylindrical, and then by heat-sealing the second plastic base material layers 12 of the strong bonding regions 21 at both ends in a direction different from the direction in which the second seal portion 102b extends to form a first seal portion 102a. The description of Embodiment 5 other than that is the same as that of Embodiments 1 to 4, so the description is omitted here.

[0041] [Embodiment 6] Figure 10 shows a flowchart of an example of the plastic recovery method of Embodiment 6. The example of the plastic recovery method of Embodiment 6 is characterized by having a step S1003 in which the second plastic substrate layer 12 is optically separated after the step S1002 in which the second plastic substrate layer 12 is separated.

[0042] In Embodiment 6, the first step is to produce plastic pieces, S1001. The step of producing plastic pieces, S1001, can be carried out in the same manner as in Embodiment 1. Next, after the step of producing plastic pieces, S1001, the step of separating the second plastic substrate layer 12 is carried out, S1002. In Embodiment 6, step S1002 can be carried out, for example, by immersing the plastic pieces in water and stirring as necessary, as in Embodiment 1, but it can also be carried out by applying physical force to the plastic pieces without immersion in water, or by a combination of these methods. In other words, in Embodiment 6, step S1002 can be carried out without limitation as long as it is possible to separate the second plastic substrate layer 12 without using a basic aqueous solution.

[0043] Next, after step S1002, which separates the second plastic substrate layer 12, step S1003 is performed to optically sort the second plastic substrate layer 12. Step S1003 can be performed, for example, by sorting the plastic pieces made of the second plastic substrate layer 12 from all the plastic pieces after step S1002 (plastic pieces formed by joining the first laminate 1a and the second laminate 1b, plastic pieces made of the first plastic substrate layer 10, and plastic pieces made of the second plastic substrate layer 12) using a conventionally known optical sorter. Optical sorting of the plastic pieces made of the second plastic substrate layer 12 becomes possible when the plastic pieces made of the second plastic substrate layer 12 separated in step S1002 are colorless, and the other plastic pieces (plastic pieces formed by joining the first laminate 1a and the second laminate 1b, and plastic pieces made of the first plastic substrate layer 10) are colored, for example, because they contain the design printing layer 15. In this case as well, it is possible to separate and recover the second plastic substrate layer 12 without using a basic aqueous solution.

[0044] [others] It should be noted that Embodiment 1 and Embodiment 2 differ in their methods of joining the first plastic substrate layer 10 and the second plastic substrate layer 12, and Embodiments 1 and 2 differ from Embodiments 3 and 4 in their lamination configurations of the first plastic substrate layer 10. However, it goes without saying that the configurations of each embodiment may be combined (for example, the lamination configuration of the first plastic substrate layer 10 of Embodiment 3 or Embodiment 4 may be combined with the joining method of Embodiment 2). [Examples]

[0045] <Preparation of small plastic pieces> First, a laminate 1 having the layered structure shown in Figure 8 was stacked on top of each other, and a portion of it was heat-sealed to produce a pouch 100 as shown in Figure 3. Then, the pouch 100 thus produced was crushed into small pieces using a conventionally known crusher to produce plastic fragments. The specific configuration of the laminate 1 used to produce the plastic fragments is shown below.

[0046] Second plastic substrate layer 12: LLDPE film (one of the following thicknesses: 70 μm, 100 μm, 120 μm, or 150 μm) Adhesive layer 16: Conventional known adhesive Adhesion inhibiting layer 17: Conventional known release ink 1-1 Plastic substrate layer 11: PET film (thickness 12 μm) Deposition layer 14: Aluminum deposition 1st-2nd plastic substrate layer 13: Ny film (thickness 15 μm) Plastic substrate layers 1-3 19: PET film (one of the following thicknesses: 70 μm, 100 μm, 120 μm, or 150 μm)

[0047] Specifically, without changing the materials and thicknesses of the adhesive layer 16, adhesion inhibiting layer 17, the first-1 plastic substrate layer 11, and the first-2 plastic substrate layer 13 of the laminate 1 having the laminated structure shown in Figure 8, several types of plastic pieces were produced by changing the thickness of the LLDPE film constituting the second plastic substrate layer 12 and the thickness of the PET film constituting the first-3 plastic substrate layer 19.

[0048] Furthermore, several types of plastic pieces were produced by changing the thickness of the LLDPE film constituting the second plastic substrate layer 12, in the same manner as described above, except that the first to third plastic substrate layers 19 were not laminated.

[0049] <First evaluation of plastic separation> The plastic fragments prepared as described above were immersed in water and then stirred. As a result, the proportion of the second plastic substrate layer 12 that could be separated and recovered by floating only on the water surface was calculated. The results are shown in Table 1.

[0050] [Table 1]

[0051] In Table 1, the letters to the left of "PE70," "PE100," "PE120," and "PE150" indicate that the second plastic substrate layer 12 of the laminate 1 constituting the plastic piece is made of LLDPE film (specific gravity 0.92), and the numbers to the right indicate the thickness (μm) of the second plastic substrate layer 12. Also in Table 1, the letters to the left of "PET12," "PET20," "PET30," and "PET60" indicate that the first to third plastic substrate layers 19 of the laminate 1 constituting the plastic piece are made of biaxially oriented PET film, and the numbers to the right indicate the thickness (μm) of the first to third plastic substrate layers 19. In Table 1, "None" indicates that the laminate 1 constituting the plastic piece does not have the first to third plastic substrate layers 19. Also, an upward-sloping diagonal line in the column of Table 1 means that the test was not performed.

[0052] In Table 1, the value in the "Specific Gravity" column indicates the specific gravity of the entire laminate 1 constituting the plastic fragments, and the value in the "Floating [%]" column indicates the percentage [%] of the total number of plastic fragments immersed in water in which only the second plastic substrate layer 12 floated on the water surface and the separation of the second plastic substrate layer 12 could be confirmed. In Table 1, "-" indicates that all the plastic fragments floated in the water and the second plastic substrate layer 12 could not be separated.

[0053] As shown in Table 1, it was confirmed that the second plastic substrate layer 12 can be separated when the specific gravity of the entire laminate 1 constituting the plastic fragment is 1 or greater.

[0054] <Second evaluation of plastic separation> The plastic separation was evaluated in the same manner as in the first evaluation described above, except that a surfactant was added to the water in which the plastic fragments were immersed. The results are shown in Table 2.

[0055] [Table 2]

[0056] In Table 2, "0.1%" indicates that 0.1% of surfactant was added to the water in which the plastic pieces were immersed, and "0.5%" indicates that 0.5% of surfactant was added to the water in which the plastic pieces were immersed. Note that "0.1%" and "0.5%" mean that 0.1g and 0.5g of surfactant were added to 100g of water in which the plastic pieces were immersed, respectively. Furthermore, the values ​​in the "0.1%" and "0.5%" columns in Table 2, similar to the values ​​in the "Floating [%]" column in Table 1, represent the percentage [%] of the total number of plastic pieces immersed in water in which only the second plastic substrate layer 12 floated on the water surface, allowing for the separation of the second plastic substrate layer 12 to be confirmed. Other notations in Table 2 are the same as in Table 1, so their explanations are omitted.

[0057] As shown in Table 2, it was confirmed that when a surfactant was added to the water in which the plastic pieces were immersed, the second plastic substrate layer 12 could be separated from all of the plastic pieces.

[0058] As described above, embodiments and examples have been explained, but it is also planned from the outset that the configurations of each of the above embodiments and examples may be combined as appropriate.

[0059] The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Industrial applicability]

[0060] This disclosure can be suitably used, for example, to separate and recover plastic from packaging such as pouches and pillow packaging. [Explanation of Symbols]

[0061] 1 Laminate, 10 First plastic substrate layer, 11 First-1 plastic substrate layer, 12 Second plastic substrate layer, 13 First-2 plastic substrate layer, 14 Vapor deposition layer, 15 Design printing layer, 16 Adhesive layer, 17 Adhesion inhibiting layer, 19 First-3 plastic substrate layers, 20 Dashed line, 21 Strong bonding area, 22 Weak bonding area, 100 Pouch, 101 Non-sealed area, 102 Sealed area, 102a First sealed area, 102b Second sealed area, 103 Spout, 200 Pillow packaging.

Claims

1. A first plastic substrate layer, A laminate comprising a second plastic substrate layer bonded to the first plastic substrate layer, The laminate is provided with a strongly bonded region where the first plastic substrate layer and the second plastic substrate layer are bonded, and a weakly bonded region and / or a non-bonded region adjacent to the strongly bonded region. The weak bonding region is a region in which the bonding strength between the first plastic substrate layer and the second plastic substrate layer is lower than that of the strong bonding region. The laminate is a region in which the first plastic substrate layer and the second plastic substrate layer are not bonded together.

2. The laminate according to claim 1, wherein the total specific gravity of the laminate is 1 or more, the specific gravity of the first plastic substrate layer is 1 or more, and the specific gravity of the second plastic substrate layer is less than 1.

3. The laminate according to claim 1, wherein the first plastic substrate layer further comprises a design printing layer.

4. The laminate according to claim 1, wherein, when the laminate is viewed from above, the area of ​​the strongly bonded region is 35% or less of the total area of ​​the laminate.

5. A packaging comprising a laminate according to any one of claims 1 to 4, The packaging has a sealed portion in which the laminates are sealed to each other, and an unsealed portion in which the laminates are not sealed to each other. A packaging body in which the weakly bonded region and / or the non-bonded region are located in the non-sealed portion.

6. A method for recovering the second plastic substrate layer from the packaging described in claim 5, A step of producing plastic fragments by crushing the aforementioned packaging, A method for recovering plastic, comprising the step of separating the second plastic substrate layer from the plastic fragment without using a basic aqueous solution.

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