Packaging container, and method of reducing carbon dioxide discharge amount

Abstract

To reduce a carbon dioxide discharge amount.SOLUTION: A packaging container 10 is a packaging container formed from a resin sheet 20. The resin sheet 20 comprises: a recycled polyester layer 21 containing recycled polyester comprising a bottle recycled material made from a used PET bottle; and virgin polyester layers 22 each containing no recycled polyester, that are laminated on one side or both sides of the recycled polyester layer 21. The resin sheet 20 has a total thickness of 0.4 mm or less. A carbon dioxide discharge amount of the packaging container 10 formed from the resin sheet 20 comprising the recycled polyester layer 21 and the virgin polyester layers 22 with respect to a comparative packaging container formed from the comparative resin sheet consisting of only the virgin polyester layers has a reduction rate of 10% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to packaging containers and methods for reducing carbon dioxide emissions when producing packaging containers. [Background technology]

[0002] For example, Patent Document 1 discloses a packaging container obtained by collecting and reusing food containers. The packaging container disclosed in Patent Document 1 includes a container body that contains food and is open at the top, and a lid that is attached to the container body and closes the opening of the container body.

[0003] The container body and the lid are formed from a resin sheet in which a polyester layer and a recycled polyester layer are laminated. The polyester layer is a layer formed from unused (in other words, not recycled) polyester. The recycled polyester layer is a layer obtained by reusing used polyester containers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-278739 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, carbon dioxide may be generated in the process of producing a packaging container, in the process of disposing of a used packaging container, etc. From an environmental perspective, it is preferable that the amount of carbon dioxide emissions generated by the packaging container in the process of producing or disposing of the packaging container is small.

[0006] The present invention has been made in consideration of these points, and its purpose is to provide a packaging container that can reduce carbon dioxide emissions when the packaging container is manufactured or disposed of, and a method for reducing carbon dioxide emissions. [Means for solving the problem]

[0007] The packaging container according to the present invention is a packaging container formed from a resin sheet. The resin sheet comprises a recycled polyester layer containing recycled polyester with bottle recycled material made from used PET bottles, and a virgin polyester layer laminated on one or both sides of the recycled polyester layer and not containing the recycled polyester. The resin sheet has a total thickness of 0.4 mm or less. The packaging container is characterized in that the carbon dioxide emission reduction rate of the packaging container formed from the resin sheet comprising the recycled polyester layer and the virgin polyester layer is 10% or more compared to a comparative packaging container formed from a comparative resin sheet consisting only of the virgin polyester layer.

[0008] According to the packaging container, recycled bottle materials made from used PET bottles can relatively reduce carbon dioxide emissions. Therefore, by forming a packaging container from a resin sheet having a recycled polyester layer containing recycled bottle materials, carbon dioxide emissions can be reduced by 10% or more compared to a comparative packaging container formed from a comparative resin sheet consisting only of a virgin polyester layer.

[0009] According to a preferred embodiment of the present invention, the packaging container formed from the resin sheet has an intrinsic viscosity IV value of 0.55 dL / g or more and 0.75 dL / g or less.

[0010] According to the above embodiment, the intrinsic viscosity IV value is made relatively low, thereby making it possible to reduce carbon dioxide emissions.

[0011] According to another preferred embodiment of the present invention, the ratio of the thickness of the recycled polyester layer to the total thickness of the resin sheet is 70% or more.

[0012] According to the above-described embodiment, by increasing the thickness of the recycled polyester layer, the amount of bottle recycled material contained in the resin sheet can be increased, and therefore, a packaging container can be formed using a resin sheet containing a large amount of bottle recycled material, thereby reducing carbon dioxide emissions.

[0013] The method for reducing carbon dioxide emissions according to the present invention is a method for reducing carbon dioxide emissions when manufacturing a packaging container. In the method for reducing carbon dioxide emissions, the packaging container is formed from a resin sheet including a recycled polyester layer containing recycled polyester made from used polyester and a virgin polyester layer laminated on one or both sides of the recycled polyester layer and not containing the recycled polyester, and the resin sheet is made from recycled bottle material made from used PET bottles.

[0014] According to the method for reducing carbon dioxide emissions, recycled bottle materials made from used PET bottles can reduce carbon dioxide emissions relatively. Therefore, by forming a resin sheet made from recycled bottle materials and producing a packaging container, it is possible to reduce carbon dioxide emissions when producing the packaging container. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a packaging container that can reduce the amount of carbon dioxide emitted when the packaging container is produced or disposed of, and a method for reducing carbon dioxide emissions. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a packaging container according to an embodiment. [Figure 2]FIG. 2 is a cross-sectional view showing a part of a packaging container and a cross-sectional view of a resin sheet. [Figure 3] FIG. 1 is a diagram schematically illustrating an extrusion device used in extrusion molding. [Figure 4] FIG. 1 is a schematic diagram showing a mold and plug used in thermoforming. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of a packaging container according to the present invention will be described with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention. Furthermore, the same reference numerals are used for components and parts that perform the same functions, and redundant descriptions will be omitted or simplified as appropriate.

[0018] 1 is a perspective view showing a packaging container 10 according to this embodiment. The packaging container 10 is a container in which, for example, food is stored. However, the packaging container 10 is not limited to a container in which food is stored. The packaging container 10 may be a container that is heated in a microwave oven or the like, or may be a container that is not heated (for example, a container for unheated food).

[0019] As shown in FIG. 1 , the packaging container 10 includes a container body 11 and a lid 15. In this embodiment, the packaging container 10 includes both the container body 11 and the lid 15. However, the packaging container 10 may include at least one of the container body 11 and the lid 15. That is, the packaging container 10 may include the container body 11 but not the lid 15. Alternatively, the packaging container 10 may include the lid 15 but not the container body 11. Hereinafter, the packaging container 10 may be appropriately referred to as the container body 11 and the lid 15. In this embodiment, the packaging container 10, i.e., the container body 11 and the lid 15, are formed from a resin sheet 20. The type, use, shape, etc. of the packaging container 10 are not particularly limited as long as it is formed from the resin sheet 20. The configurations and shapes of the container body 11 and the lid 15 described below are merely examples.

[0020] As shown in FIG. 1 , container body 11 has bottom 12 and sidewall 13. Bottom 12 constitutes the bottom portion of container body 11. Sidewall 13 rises from bottom 12. Sidewall 13 extends upward, for example, from an edge (e.g., a peripheral edge) of bottom 12. Sidewall 13 is disposed so as to surround bottom 12 in a plan view. Sidewall 13 may extend perpendicular to bottom 12, or may extend obliquely upward and outward from bottom 12. In other words, sidewall 13 may be inclined outward from bottom 12 as it moves away from bottom 12. Bottom 12 and sidewall 13 may have flat surfaces, or may have protrusions or recesses (not shown) or so-called ribs to increase rigidity. Here, food or the like is contained in the space surrounded by bottom 12 and sidewall 13.

[0021] In this embodiment, the bottom 12 has a circular shape. However, the shape of the bottom 12 is not particularly limited, and the shape of the container body 11 is also not particularly limited. Here, the container body 11 has a container opening (not shown) surrounded by a side wall 13. The container opening is formed by, for example, the upper end of the side wall 13 and opens upward.

[0022] As shown in Fig. 1, the lid 15 can be attached to the container body 11. Here, the lid 15 is attached to the container body 11 so as to be able to freely open and close the container opening of the container body 11. The lid 15 closes the container opening by being attached to the upper end of the side wall portion 13 of the container body 11. The lid 15 fits into the container body 11.

[0023] In this embodiment, the lid body 15 includes a top surface portion 16 and a fitting portion 17. The top surface portion 16 forms the top surface of the lid body 15. When the lid body 15 is attached to the container body 11, the top surface portion 16 faces the bottom portion 12. For example, when the lid body 15 is attached to the container body 11, the top surface portion 16 is arranged so as to be parallel to the bottom portion 12.

[0024] The fitting portion 17 fits into the container body 11 when the lid 15 is attached to the container body 11. In this embodiment, the fitting portion 17 can fit into the upper end of the side wall 13 of the container body 11. The fitting portion 17 is provided at an end (e.g., a peripheral edge) of the top surface 16 in a plan view. The fitting portion 17 is provided so as to surround the top surface 16 in a plan view. Here, the fitting portion 17 protrudes upward from the top surface 16. The fitting portion 17 is disposed at a position corresponding to the upper end of the side wall 13 when the lid 15 is attached to the container body 11. Note that the specific configuration of the fitting portion 17 is not particularly limited. For example, the fitting portion 17 may be provided with a recess into which the upper end of the side wall 13 of the container body 11 is fitted. The recess is provided so as to surround the top surface 16 in a plan view and is configured to be recessed upward from the bottom surface of the fitting portion 17.

[0025] In this embodiment, an opening valve 18 is formed on the top surface 16 of the lid 15. The opening valve 18 is a valve that allows gas or liquid to enter and exit. For example, if the packaging container 10 is a container that contains food and is placed in a microwave oven or the like to be heated, when the packaging container 10 is heated, the food is heated and steam (e.g., water vapor) is generated. The opening valve 18 of the lid 15 is closed before heating in the microwave oven. When the food is heated in the microwave oven, that is, when steam generated by heating the food is discharged to the outside of the lid 15, the opening valve 18 opens and the steam passes through the opening valve 18. After the steam passes, the opening valve 18 returns to its original closed state. Note that the number and positions of the opening valves 18 formed on the top surface 16 are not particularly limited. In this embodiment, the number of opening valves 18 formed on the top surface 16 of the lid 15 is two. The opening valves 18 are formed in the center of the top surface 16.

[0026] As shown in FIG. 1 , the opening valve 18 has an opening 19a formed in the top surface 16 and a valve element 19b that can open and close the opening 19a. Gas and liquid pass through the opening 19a. The valve element 19b is connected to the top surface 16. In this embodiment, the opening valve 18 is formed by cutting a notch in the top surface 16. The cut portion of the top surface 16 becomes the opening 19a and the valve element 19b. Therefore, the valve element 19b has a shape that matches the opening 19a. The valve element 19b is formed integrally with the top surface 16. The shape of the valve element 19b is, for example, U-shaped. However, the shape of the valve element 19b is not particularly limited and may be, for example, C-shaped. Note that, although the opening valve 18 is formed in the lid body 15 in this embodiment, the opening valve 18 does not necessarily have to be formed. A packaging container 10 having a lid body 15 without the opening valve 18 is, for example, a container for unheated food.

[0027] As described above, the container body 11 and the lid 15 are formed from the resin sheet 20. Next, the resin sheet 20 will be described. The resin sheet 20 is a sheet formed from polyester (in other words, polyester resin), and is a so-called polyester sheet. The resin sheet 20 is formed from, for example, polyethylene terephthalate (hereinafter also referred to as PET or PET resin). However, the material forming the resin sheet 20 is not limited to PET, and may be, for example, polylactic acid (hereinafter also referred to as PLA). PLA is a type of biodegradable plastic made from agricultural products such as corn, potatoes, sugarcane, and beets.

[0028] Fig. 2 is a cross-sectional view of the resin sheet 20 of the packaging container 10. As shown in Fig. 2, the resin sheet 20 is formed from a plurality of layers. The number of layers forming the resin sheet 20 is not particularly limited. Below, a resin sheet 20 formed from three layers will be described.

[0029] In this embodiment, the resin sheet 20 includes a recycled polyester layer 21 and a virgin polyester layer 22 (here, two virgin polyester layers 22). The resin sheet 20 is a sheet in which the recycled polyester layer 21 and the virgin polyester layer 22 are laminated.

[0030] The recycled polyester layer 21 is a layer containing recycled polyester. Here, recycled polyester is made of used polyester. Used polyester is polyester obtained from used polyester products. Used polyester products are, for example, used polyester products collected from the market. Here, polyester products refer to, for example, PET bottles (hereinafter also referred to as PET bottles) and PET trays. Recycled polyester is polyester obtained by collecting used polyester products, that is, recycled polyester. Also, recycled polyester is polyester obtained by collecting used polyester products based on a predetermined recycling method.

[0031] In this embodiment, recycled polyester made from used PET bottles is referred to as bottle recycled material. Recycled polyester includes bottle recycled material. Bottle recycled material refers to polyester obtained from used PET bottles collected from the market. Here, the recycled polyester layer 21 contains bottle recycled material. Note that recycled polyester may also include polyester other than bottle recycled material, such as container recycled material obtained from used food containers made of PET resin.

[0032] Here, recycling methods for polyester products such as PET bottles include material recycling, chemical recycling, and mechanical recycling. Material recycling involves crushing recovered polyester products, then alkaline cleaning them and reusing them as fibers, etc. Chemical recycling involves chemically decomposing recovered polyester products, returning them to raw material level, and polymerizing the PET again. Mechanical recycling involves subjecting recovered polyester products to more rigorous alkaline cleaning than in the material recycling described above, or thoroughly removing dirt from the polyester products by vacuum drying at high temperatures, etc., before reusing them. Here, polyester reused by mechanical recycling is referred to as mechanically recycled polyester. In this embodiment, the recycled polyester is, for example, mechanically recycled polyester.

[0033] The recycled polyester layer 21 may contain a polyester other than recycled polyester (for example, PET). Here, examples of polyester other than recycled polyester contained in the recycled polyester layer 21 include virgin polyester, which will be described later. In this embodiment, the recycled polyester contained in the recycled polyester layer 21 is 50% by mass or more, preferably 60% by mass or more, particularly preferably 70% by mass or more, for example, 80% by mass or more.

[0034] The recycled polyester layer 21 may contain waste during the manufacturing process, such as edge waste and skeleton waste, which occurs when producing the resin sheet 20 and the packaging container 10, as long as this does not significantly impair formability.

[0035] The virgin polyester layer 22 is a layer that does not contain recycled polyester. The virgin polyester layer 22 is a layer that contains so-called virgin polyester. The virgin polyester layer 22 is formed from virgin polyester. Here, virgin polyester refers to polyester that does not contain recycled polyester and is unused (in other words, not reused) polyester. Virgin polyester is a new material. The virgin polyester layer 22 is a layer that is not formed from recycled polyester that includes bottle recycled material, but is formed from unused polyester. Virgin polyester is different from recycled polyester that is obtained from used polyester products collected from the market.

[0036] For example, virgin polyester may contain plant-derived polyester. An example of plant-derived polyester is plant-derived PET. Plant-derived polyester refers to polyester produced using plant-derived raw materials such as corn, potato, sugarcane, and beet. Plant-derived PET refers to PET produced using the above plant-derived raw materials. Virgin polyester may contain, for example, petroleum-derived polyester. Either plant-derived or petroleum-derived polyester may be used as virgin polyester. Petroleum-derived polyester (e.g., PET) refers to polyester made from petroleum.

[0037] Note that the virgin polyester layer 22 may contain other components besides polyester (e.g., PET) as needed, provided that the transparency and functionality are not significantly impaired. Examples of such other components include additives used in known resin sheets (e.g., flame retardants, ultraviolet absorbers, fluorescent brighteners, antistatic agents, anti-fog agents, lubricants (e.g., MB (masterbatch) lubricant), anti-blocking agents, flowability modifiers, plasticizers, dispersants, antibacterial agents, etc.).

[0038] In this embodiment, as shown in Figure 2, virgin polyester layers 22 are laminated on both sides of the recycled polyester layer 21. Here, the virgin polyester layers 22 are provided on both broad surfaces of the recycled polyester layer 21 (top and bottom surfaces in Figure 2). Here, the number of virgin polyester layers 22 is two. The recycled polyester layer 21 is sandwiched between the two virgin polyester layers 22.

[0039] Each recycled polyester layer 21 may be a single layer or a multilayer, and may be formed by laminating multiple layers (here, recycled polyester layers). Similarly, each virgin polyester layer 22 may be a single layer or a multilayer, and may be formed by laminating multiple layers (here, virgin polyester layers).

[0040] In this embodiment, the overall thickness of the resin sheet 20 (in other words, the thickness of the container body 11 and the lid 15) is 1.0 mm or less, preferably 0.6 mm or less, and particularly preferably 0.4 mm or less, for example, 0.25 mm or less, making the resin sheet 20 relatively thin. Here, the thickness of the resin sheet 20 refers to the overall thickness of the recycled polyester layer 21 and the virgin polyester layer 22 combined. In this embodiment, of the recycled polyester layer 21 and the virgin polyester layer 22 of the resin sheet 20, the recycled polyester layer 21 is thicker than the virgin polyester layer 22. For example, the ratio of the thickness of the recycled polyester layer 21 to the overall thickness of the resin sheet 20 is 50% or more and 98% or less, preferably 70% or more and 98% or less, and particularly preferably 80% or more and 98% or less. For example, the thickness ratio of the recycled polyester layer 21 to the virgin polyester layer 22 can be recycled polyester layer:virgin polyester layer = 92:8 or 80:20, but is not limited to these ratios. In this embodiment, the thicknesses of the two virgin polyester layers 22 are the same. However, the thicknesses of the two virgin polyester layers 22 may be different.

[0041] The resin sheet 20 according to the present embodiment has been described above. Here, as shown in FIG. 2, the packaging container 10 (in other words, the container body 11 and the lid 15) includes an inner layer 31, an outer layer 32, and an intermediate layer 33. In FIG. 2, the upper side indicates the inside of the container body 11 and the lid 15, and the lower side indicates the outside of the container body 11 and the lid 15. The inner layer 31 is the innermost layer among the multiple layers that make up the container body 11 and the lid 15. The inner layer 31 is the layer that makes up the inner circumferential surface of the packaging container 10. The inner layer 31 is the layer that comes into direct contact with food when the food is contained in the packaging container 10. The outer layer 32 is the outermost layer among the multiple layers that make up the container body 11 and the lid 15, and is the layer that makes up the outer circumferential surface of the packaging container 10. The outer layer 32 is the layer that comes into direct contact with a user's hand, for example, when the user holds the packaging container 10 in their hand.

[0042] The intermediate layer 33 is a layer disposed between the inner layer 31 and the outer layer 32. As shown in Fig. 2, the intermediate layer 33 is sandwiched between the inner layer 31 and the outer layer 32. Therefore, the intermediate layer 33 can be a layer that is not in direct contact with food or the user. Each of the inner layer 31, the outer layer 32, and the intermediate layer 33 may be a single layer, or may be a layer formed by laminating multiple layers.

[0043] In this embodiment, in the container body 11 and the lid body 15 of the packaging container 10, the inner layer 31 and the outer layer 32 are formed of the virgin polyester layer 22 of the resin sheet 20. The middle layer 33 is formed of the recycled polyester layer 21 of the resin sheet 20.

[0044] In this embodiment, the packaging container 10, i.e., the container body 11 and the lid body 15 (in other words, the resin sheet 20), is transparent. In other words, the recycled polyester layer 21 and the virgin polyester layer 22 are transparent. In this embodiment, the haze value of the packaging container 10 (in other words, the container body 11 and the lid body 15) is less than 5.0%, preferably less than 3.0%, particularly preferably less than 2.0%, for example, less than 1.6%.

[0045] In this embodiment, the intrinsic viscosity IV value of the packaging container 10 (here, the container body 11 and the lid body 15) is 0.55 dl / g or more and 0.75 dl / g or less, preferably 0.57 dl / g or more and 0.73 dl / g or less, particularly preferably 0.59 dl / g or more and 0.71 dl / g or less, for example, 0.62 dl / g or more and 0.68 dl / g or less.

[0046] Next, a method for producing the resin sheet 20 and packaging container 10 according to this embodiment, i.e., a method for producing the packaging container 10, will be described. The method for producing the packaging container 10 includes a step of preparing pellets, a step of performing extrusion molding, and a step of performing thermoforming. Here, the resin sheet 20 can be produced by preparing pellets and performing extrusion molding on the pellets. Then, the resin sheet 20 can be thermoformed to produce the packaging container 10, i.e., the container body 11 and the lid 15.

[0047] Here, first, in the pellet preparation step, virgin pellets made from virgin polyester and recycled pellets made from recycled polyester containing bottle recycled material are prepared. The recycled pellets are made, for example, from used polyester resin molded products (in other words, used polyester products) collected from the market. Used polyester products are, for example, used PET bottles, used PET containers such as used PET trays, etc. In other words, the recycled pellets are pellets containing bottle recycled material made from used PET bottles. Here, the recycled pellets are made by crushing polyester products such as used PET bottles collected from the market, removing foreign matter, washing, and drying.

[0048] Next, in the extrusion molding step, the virgin pellets and the recycled pellets are extruded to produce a resin sheet 20. FIG. 3 is a diagram schematically illustrating an extrusion device 50 used in the extrusion molding. In this embodiment, the extrusion device 50 shown in FIG. 3 is used in the extrusion molding. As shown in FIG. 3, the extrusion device 50 has a first hopper 51A, a first screw 52A, a second hopper 51B, a second screw 52B, a feed block 58, a confluence die 53, a cooling roll 54, and a winder 55.

[0049] In this embodiment, the first hopper 51A and the first screw 52A are for virgin pellets (hereinafter referred to as "virgin"). The second hopper 51B and the second screw 52B are for recycled pellets (hereinafter referred to as "recycled"). The first hopper 51A is connected to the first screw 52A, and a first heater 57A is provided around the first screw 52A. The second hopper 51B is connected to the second screw 52B, and a second heater 57B is provided around the second screw 52B. The first screw 52A and the second screw 52B are connected to a feed block 58. The feed block 58 is connected to a joining die 53.

[0050] In extrusion molding, virgin pellets 40A are first placed in a first hopper 51A. For virgin pellets, the virgin pellets 40A placed in the first hopper 51A are passed through a first screw 52A and mixed by the rotation of the first screw 52A while being heated by a first heater 57A. The virgin pellets 40A mixed by the first screw 52A are then passed toward a narrow feed block 58. Similarly, for recycled pellets, recycled pellets 40B are placed in a second hopper 51B. The recycled pellets 40B placed in the second hopper 51B are passed through a second screw 52B and mixed by the rotation of the second screw 52B while being heated by a second heater 57B. The recycled pellets 40B mixed by the second screw 52B are then passed toward the feed block 58.

[0051] In the feed block 58, the virgin pellets 40A and the recycled pellets 40B join together and flow into the joining die 53. In the joining die 53, a layer of virgin pellets 40A and a layer of recycled pellets 40B are extruded (co-extruded here) by the feed block 58 and discharged. Here, the layer of virgin pellets 40A extruded from the joining die 53 by the feed block 58 becomes the virgin polyester layer 22 (see FIG. 2). The layer of recycled pellets 40B extruded from the joining die 53 by the feed block 58 becomes the recycled polyester layer 21 (see FIG. 2).

[0052] In this embodiment, although detailed illustration is omitted, in a heated state, the virgin polyester layer 22, the recycled polyester layer 21, and the virgin polyester layer 22 are stacked in this order to form a sheet, which is then discharged from the joining die 53. At this time, the virgin polyester layer 22 and the recycled polyester layer 21 are bonded to each other to form the resin sheet 20.

[0053] In this embodiment, as shown in Fig. 3, a cooling roll 54 and a winder 55 are arranged in this order downstream of the confluence die 53, i.e., at the destination of the resin sheet 20 discharged from the confluence die 53. The resin sheet 20 discharged from the confluence die 53 passes through the cooling roll 54. Here, the resin sheet 20 discharged from the confluence die 53 is in a heated state, so it is cooled by passing through the cooling roll 54. The resin sheet 20 passing through the cooling roll 54 is transported toward the winder 55 and wound into a roll by the winder 55. The resin sheet 20 is produced by the above procedure.

[0054] Next, in the thermoforming step, the resin sheet 20 is thermoformed to produce the packaging container 10, i.e., the container body 11 and the lid 15. Here, thermoforming can also be referred to as vacuum forming, pressure forming, or a combination of vacuum forming and pressure forming. FIG. 4 is a schematic diagram showing a mold 60 and a plug 65 used in thermoforming. As shown in FIG. 4, the mold 60 and the plug 65 are used in thermoforming. The mold 60 has a recess 61 formed therein. The plug 65 has a protrusion 66 formed therein to be inserted into the recess 61 of the mold 60. Here, during thermoforming, the mold 60 and the plug 65 are spaced apart so that the recess 61 and the protrusion 66 face each other. Then, the heated resin sheet 20 is placed between the mold 60 and the plug 65. At this time, the resin sheet 20 is placed so that one of the two virgin polyester layers 22 of the resin sheet 20 is located on the plug 65 side and the other of the two virgin polyester layers 22 is located on the mold 60 side.

[0055] 4, the mold 60 or the plug 65 is moved, and the convex portion 66 of the plug 65 is inserted into the concave portion 61 of the mold 60. As a result, the resin sheet 20 is thermoformed between the concave portion 61 and the convex portion 66 along the shapes of the concave portion 61 and the convex portion 66, and the thermoformed resin sheet 20 is appropriately cut to produce the packaging container 10.

[0056] In this embodiment, a mold 60 and a plug 65 for producing the container body 11, and a mold 60 and a plug 65 for producing the lid 15 are prepared. When producing the container body 11, the recess 61 of the mold 60 and the protrusion 66 of the plug 65 have shapes corresponding to the shape of the container body 11. When producing the lid 15, the recess 61 of the mold 60 and the protrusion 66 of the plug 65 have shapes corresponding to the shape of the lid 15.

[0057] From an environmental perspective, there is a demand for a reduction in carbon dioxide emissions. In this embodiment, a method for reducing carbon dioxide emissions is realized. The method for reducing carbon dioxide emissions here is a method for reducing carbon dioxide emissions when manufacturing the packaging container 10. Here, by using a bottle recycled material made from used PET bottles for the resin sheet 20, it is possible to reduce carbon dioxide emissions.

[0058] For example, carbon dioxide is generated during thermoforming when a packaging container is made from a resin sheet, and when the packaging container is disposed of or incinerated after use. In the resin sheet that forms the packaging container, the virgin polyester (e.g., petroleum-derived polyester) in the virgin polyester layer is produced as pellets by subjecting the petroleum raw material to a chemical reaction such as polymerization. For example, with virgin polyester, carbon dioxide is generated when the petroleum is mined and when the petroleum is polymerized. The carbon dioxide emissions from packaging containers referred to here refer to the amount of carbon dioxide generated when the packaging container is made (including petroleum mining) and when the packaging container is disposed of.

[0059] On the other hand, recycled polyester, unlike virgin polyester, does not require new mining of raw materials, so it emits less carbon dioxide. In particular, recycled polyester made from recycled bottles, which are made from used PET bottles, is thought to emit less carbon dioxide. For example, recycled bottle materials are thought to emit less carbon dioxide than recycled container materials made from used food containers.

[0060] For example, among recycled polyester, petroleum-derived polyester, and plant-derived polyester contained in a resin sheet, the carbon dioxide emissions are lowest in the order of recycled polyester, plant-derived polyester, and petroleum-derived polyester, with recycled polyester having the lowest carbon dioxide emissions. Therefore, in this embodiment, a method for reducing carbon dioxide emissions includes incorporating a recycled polyester layer 21 containing recycled polyester into a resin sheet 20, and forming a packaging container 10 from the resin sheet 20, thereby reducing the carbon dioxide emissions of the packaging container 10. Furthermore, in the method for reducing carbon dioxide emissions according to this embodiment, the resin sheet 20 uses recycled bottle material made from used PET bottles, thereby further reducing carbon dioxide emissions.

[0061] In this embodiment, the overall thickness of the resin sheet 20 is relatively thin, being 1.0 mm or less, preferably 0.4 mm or less. Furthermore, the recycled polyester layer 21 is made thick by increasing the ratio of its thickness to the overall thickness of the resin sheet 20. By making the recycled polyester layer 21 as thick as possible while reducing the overall thickness of the resin sheet 20 in this way, it is possible to increase the proportion of recycled polyester (e.g., recycled bottle material) contained. By producing a packaging container 10 using a resin sheet 20 that contains a large amount of recycled polyester in this way, carbon dioxide emissions can be further reduced.

[0062] For example, when polymerizing PET resin such as polyester, the higher the polymerization temperature, the faster the reaction rate and the higher the molecular weight. Furthermore, the longer the polymerization time, the more monomers react, resulting in a higher molecular weight. Here, a higher polymerization temperature and a longer polymerization time result in a higher molecular weight of the PET resin. This can be expected to improve the strength, such as the modulus of elasticity, of a resin sheet made from PET resin. However, the higher the molecular weight, the greater the carbon dioxide emissions. Furthermore, the stronger the strength and the higher the intrinsic viscosity IV value, the greater the carbon dioxide emissions. In this embodiment, as described above, the intrinsic viscosity IV value of the packaging container 10 is relatively low, approximately 0.55 dL / g or more and 0.75 dL / g or less. Thus, it is believed that reducing the intrinsic viscosity IV value can reduce carbon dioxide emissions.

[0063] In this embodiment, a resin sheet consisting only of a virgin polyester layer 22 is referred to as a comparative resin sheet. The comparative resin sheet is a single-layer sheet having a virgin polyester layer 22 and no recycled polyester layer 21. The comparative resin sheet is also a sheet containing virgin polyester and does not contain recycled polyester such as bottle recycled material. The overall thickness of the comparative resin sheet is the same as the overall thickness of the resin sheet 20 according to this embodiment. A packaging container formed from such a comparative resin sheet is referred to as a comparative packaging container.

[0064] In this embodiment, carbon dioxide emissions can be reduced by including recycled polyester (here, recycled bottle material) in the resin sheet 20. Here, the reduction rate of carbon dioxide emissions of the packaging container 10 according to this embodiment compared to the comparative packaging container is 10% or more, preferably 20% or more, and particularly preferably 30% or more.

[0065] Next, an evaluation test was conducted to evaluate the packaging container 10 according to this embodiment. Here, the following packaging containers, Samples 1 to 5, were prepared for the evaluation test. In Samples 1 to 5, the thickness of the resin sheet was 0.25 mm. In addition, in Samples 1 to 5, the size of the container body of the packaging container was 138 mm in length, 108 mm in width, and 20 mm in height.

[0066] <Sample 1> Sample 1 is a packaging container formed from the resin sheet according to this embodiment. In Sample 1, the thickness ratio of the inner layer, intermediate layer, and outer layer of the packaging container (hereinafter also referred to as layer ratio) is inner layer:intermediate layer:outer layer=4:92:4.

[0067] The recycled polyester layer (here, the middle layer) in Sample 1 is composed of virgin polyester and recycled polyester, containing 20% ​​by mass of virgin polyester and 80% by mass of recycled polyester. The virgin polyester layers (here, the inner and outer layers) in Sample 1 are composed of virgin polyester and lubricant MB (masterbatch), containing 94% by mass of virgin polyester and 6% by mass of lubricant MB.

[0068] In Sample 1, mechanically recycled polyester made from PET bottles collected from the market, i.e., bottle-recycled material, was used as the recycled polyester. Here, bottle-recycled PET "VF-31A" manufactured by Utsumi Recycle Systems Co., Ltd. was used as the bottle-recycled material.

[0069] The virgin polyester used in Sample 1 was a PET resin called "YS-H01" manufactured by Hainan Yisheng Petrochemical Co., Ltd., China. The intrinsic viscosity (IV) of this virgin polyester was 0.78 dL / g. Furthermore, the lubricant MB used in Sample 1 was "RE555" manufactured by Toyobo Co., Ltd. This lubricant MB was a polyester resin containing fine particles obtained by mixing 7000 ppm of spherical silica with an average particle size of 2.4 μm into a polyester resin having an intrinsic viscosity (IV) of 0.62 dL / g during polymerization (see JP 2008-30282 A).

[0070] In Sample 1, the resin sheet and packaging container were produced as follows: First, 94% by mass of virgin polyester and 6% by mass of lubricant MB were mixed to prepare a mixture for the virgin polyester layer. Next, 20% by mass of virgin polyester and 80% by mass of recycled polyester (bottle recycled material) were mixed to prepare a mixture for the recycled polyester layer.

[0071] Thereafter, extrusion molding was carried out using a twin-screw extruder (herein, extrusion device) model "SBIN-42-S2-30-L" manufactured by Plastics Technology Research Institute Co., Ltd. Here, the mixture for the virgin polyester layer and the mixture for the recycled polyester layer were supplied to the extrusion device, and melt-kneaded and extruded at a temperature of 280°C to produce a resin sheet with a thickness of approximately 0.20 mm to 0.50 mm.

[0072] Next, the above resin sheet was subjected to vacuum and pressure forming to produce a packaging container of Sample 1.

[0073] <Sample 2> The packaging container of Sample 2 is a packaging container manufactured using the same configuration and manufacturing procedure as Sample 1, except that the layer ratio of the inner layer, middle layer, and outer layer in the packaging container is inner layer: middle layer: outer layer = 10:80:10.

[0074] <Sample 3> The packaging container of Sample 3 is a packaging container made with the same configuration and manufacturing procedure as Sample 1, except that the ratio of virgin polyester (petroleum-derived polyester (PET)) to recycled polyester (bottle recycled material) in the middle layer of the packaging container is different. In Sample 3, the middle layer of the packaging container contains 50% by mass of virgin polyester and 50% by mass of recycled polyester.

[0075] <Sample 4> The packaging container of Sample 4 is a packaging container having the same structure and manufactured using the same manufacturing procedure as Sample 3, except that the layer ratio of the inner layer, middle layer, and outer layer in the packaging container is inner layer: middle layer: outer layer = 10:80:10.

[0076] <Sample 5> The packaging container of Sample 5 does not include an inner layer or an outer layer in the resin sheet produced by extrusion molding. The packaging container of Sample 5 is a packaging container produced with the same configuration and production procedure as Sample 1, except that the packaging container is produced by thermoforming a resin sheet constituted of a single layer of only a virgin polyester layer containing virgin polyester. In Sample 5, the resin sheet is constituted of a virgin polyester layer containing 100% by mass of virgin polyester (petroleum-derived polyester (PET)) and 0% by mass of recycled polyester.

[0077] The thickness, layer ratio, and composition of the resin sheets of the packaging containers of Samples 1 to 5 are shown in Table 1 below.

[0078] [Table 1]

[0079] Here, the intrinsic viscosity IV values ​​(dl / g) of the packaging containers of Samples 1 to 5 were measured in accordance with JIS K7367-5. A mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio 3 / 1) was used as the solvent. The intrinsic viscosity IV values ​​of the packaging containers of Samples 1 to 5 are shown in Table 1 above.

[0080] Next, a transparency evaluation test was conducted on the packaging containers of Samples 1 to 5. In the transparency evaluation test, the total luminous transmittance (Tt) (%) and diffuse transmittance (Td) (%) of the packaging containers of Samples 1 to 5 were measured in accordance with JIS K7136. The measured total luminous transmittance and diffuse transmittance were used to calculate the haze value (%) of the packaging container. The haze value is calculated, for example, using the formula 100×Td / Tt. The haze values ​​for the packaging containers of Samples 1 to 5 are shown in Table 1 above. Note that a lower haze value indicates better transparency.

[0081] Next, a drop test was conducted on the packaging containers of Samples 1 to 5. In the drop test, multiple packaging containers for each of Samples 1 to 5 and a 100 g weight were placed in a thermostatic chamber set at 5°C for 12 hours or more. Then, a 100 g weight was placed in each of the packaging containers of Samples 1 to 5. Then, the packaging containers of Samples 1 to 5 with the weight inside were allowed to fall freely from a height of 1.0 m onto an iron plate. Here, the drop test was conducted on 10 of each of Samples 1 to 5. After the free fall, the packaging containers of Samples 1 to 5 were visually inspected for cracks, and the number of packaging containers of Samples 1 to 5 that had cracks was counted. The results are shown in Table 1 above.

[0082] Next, the carbon dioxide emissions for the packaging containers of Samples 1 to 5 were calculated based on an LCA (Life Cycle Assessment). Here, the software "JEMAI-MiLCA ver. 1.2.6" manufactured by the Japan Environmental Management Association for Industry (JEMAI) was used to calculate the carbon dioxide emissions based on the LCA. The carbon dioxide emissions (kg-CO2) calculated based on the LCA for Samples 1 to 5 are shown in Table 1 above. The carbon dioxide emissions reduction rate (%) for the packaging containers of Samples 1 to 4 was also calculated. The carbon dioxide emissions reduction rate for the packaging containers of Samples 1 to 4 was calculated by comparing it with the carbon dioxide emissions of the packaging container of Sample 5 using the following formula (1). In the following formula (1), the comparative carbon dioxide emissions are the carbon dioxide emissions of the packaging container of Sample 5, and the target carbon dioxide emissions are the carbon dioxide emissions of the packaging containers of Samples 1 to 4. Carbon dioxide emission reduction rate = ((comparison carbon dioxide emission amount - target carbon dioxide emission amount) / comparison carbon dioxide emission amount) × 100 (1)

[0083] The carbon dioxide emission reduction rates of Samples 1 to 4 calculated based on the above formula (1) are shown in Table 1 above.

[0084] In Table 1, packaging containers Samples 1 to 4 represent packaging containers 10 according to the present embodiment. Sample 5 represents a comparative packaging container. As shown in Table 1, by incorporating recycled polyester, such as recycled bottle material, into the resin sheet, as in Samples 1 to 4, carbon dioxide emissions can be reduced, with a reduction rate of 10% or more, compared to a packaging container (comparative packaging container) formed from a resin sheet (comparative resin sheet) made solely of virgin polyester, as in Sample 5. Furthermore, as in Samples 1 and 2, increasing the proportion of recycled polyester in the recycled polyester layer (intermediate layer) can further reduce carbon dioxide emissions. Furthermore, as in Samples 1 and 3, increasing the ratio of the thickness of the recycled polyester layer (intermediate layer) to the total thickness of the resin sheet can also further reduce carbon dioxide emissions. Focusing on the intrinsic viscosity IV value, it can be seen that carbon dioxide emissions can be reduced by setting the intrinsic viscosity IV value to 0.75 dL / g or less, as in Samples 1 to 4.

[0085] In Samples 1 to 5, the overall thickness of the resin sheet was 0.25 mm, which was relatively thin. Even in packaging containers formed from such thin resin sheets, the number of cracks in the container drop test was 0, indicating that strength was ensured. Therefore, in Samples 1 to 4, it was possible to obtain packaging containers that can ensure strength while using thin resin sheets and reduce carbon dioxide emissions.

[0086] As described above, in this embodiment, as shown in FIG. 1, the packaging container 10 is a packaging container formed from a resin sheet 20. As shown in FIG. 2, the resin sheet 20 includes a recycled polyester layer 21 containing recycled polyester with bottle-recycled material made from used PET bottles, and virgin polyester layers 22 that do not contain recycled polyester and are laminated on both sides of the recycled polyester layer 21. The overall thickness of the resin sheet 20 is 0.4 mm or less. Compared to a comparative packaging container formed from a comparative resin sheet consisting only of a virgin polyester layer, the packaging container 10 formed from the resin sheet 20 including the recycled polyester layer 21 and the virgin polyester layer 22 reduces carbon dioxide emissions by 10% or more. Bottle-recycled material made from used PET bottles can relatively reduce carbon dioxide emissions. Therefore, by forming the packaging container 10 from the resin sheet 20 including the recycled polyester layer 21 containing bottle-recycled material, carbon dioxide emissions can be reduced by 10% or more compared to a comparative packaging container consisting only of a virgin polyester layer.

[0087] In this embodiment, the intrinsic viscosity IV value of the packaging container 10 formed from the resin sheet 20 is 0.55 dL / g or more and 0.75 dL / g or less. By making the intrinsic viscosity IV value relatively small in this way, it is possible to reduce carbon dioxide emissions.

[0088] In this embodiment, the ratio of the thickness of the recycled polyester layer 21 to the total thickness of the resin sheet 20 is 80% or more. In this way, by increasing the thickness of the recycled polyester layer 21, it is possible to increase the amount of bottle recycled material contained in the resin sheet 20. Therefore, the packaging container 10 can be formed using the resin sheet 20 containing a large amount of bottle recycled material, thereby reducing carbon dioxide emissions.

[0089] This embodiment provides a method for reducing carbon dioxide emissions. The method for reducing carbon dioxide emissions here is a method for reducing carbon dioxide emissions when producing a packaging container 10. In the method for reducing carbon dioxide emissions, the packaging container 10 is formed from a resin sheet 20 including a recycled polyester layer 21 containing recycled polyester made from used polyester and virgin polyester layers 22 that do not contain recycled polyester and are laminated on both sides of the recycled polyester layer 21, and the resin sheet 20 uses a bottle recycled material made from used PET bottles. In this way, by using a bottle recycled material for the resin sheet 20, it is possible to reduce carbon dioxide emissions when producing the packaging container 10.

[0090] In the above embodiment, as shown in FIG. 2 , the virgin polyester layer 22 was laminated on both sides of the recycled polyester layer 21. In other words, the virgin polyester layer 22 was disposed on both wide surfaces of the recycled polyester layer 21, and the number of virgin polyester layers 22 was two. However, the virgin polyester layer 22 may be laminated on one side of the recycled polyester layer 21. That is, the virgin polyester layer 22 may be disposed on only one of the wide surfaces of the recycled polyester layer 21, and the number of virgin polyester layers 22 may be one. In this case, the outer layer 32 may be omitted from the lid 15 of the packaging container 10. [Explanation of symbols]

[0091] 10 Packaging containers 11 Container body 15 Lid 20 Resin sheet 21 Recycled polyester layer 22 virgin polyester layers

Claims

1. A packaging container formed from a resin sheet, The resin sheet is a recycled polyester layer containing recycled polyester having a bottle recycled material made from used PET bottles; a virgin polyester layer laminated on one or both sides of the recycled polyester layer and not containing the recycled polyester; Equipped with The resin sheet has a total thickness of 0.4 mm or less, A packaging container characterized in that the carbon dioxide emissions reduction rate of a packaging container formed from the resin sheet having the recycled polyester layer and the virgin polyester layer is 10% or more compared to a comparative packaging container formed from a comparative resin sheet consisting only of the virgin polyester layer.

2. 2. The packaging container according to claim 1, wherein the packaging container formed from the resin sheet has an intrinsic viscosity (IV) value of 0.55 dl / g or more and 0.75 dl / g or less.

3. 2. The packaging container according to claim 1, wherein the thickness of the recycled polyester layer accounts for 70% or more of the total thickness of the resin sheet.

4. A method for reducing carbon dioxide emissions when producing a packaging container, comprising: A packaging container is formed from a resin sheet including a recycled polyester layer containing recycled polyester made from used polyester, and a virgin polyester layer laminated on one or both sides of the recycled polyester layer and not containing the recycled polyester, The resin sheet is made of recycled bottle material made from used PET bottles, thereby reducing carbon dioxide emissions.

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