Packaging container

Abstract

To make it difficult for the human body to be adversely affected and to ensure transparency, when using a packaging container.SOLUTION: A packaging container 10 according to the present invention is formed by a resin sheet 20. The resin sheet 20 has a recycled polyester layer 21 containing antimony and germanium and containing recycled polyester made of used polyester, and a virgin polyester layer 22 laminated on one or both sides of the recycled polyester layer 21, containing one of antimony and germanium, and not containing recycled polyester. The resin sheet 20 has a total thickness of 1.0 mm or less. In the packaging container 10, the intrinsic viscosity IV value is 0.55 dl / g or more and 0.85 dl / g or less, and the haze value is less than 5.0%. The packaging container 10 has an amount of antimony eluted that is more than 0 ppm and 0.025 ppm or less, and an amount of germanium eluted that is more than 0 ppm and 0.050 ppm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging container. [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 upward, 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 of a resin sheet in which a polyester layer and a recycled polyester layer are laminated. The polyester layer is a layer formed of unused (in other words, not reused) 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] By the way, polyester resins generally used in packaging containers are prepared by polymerizing ethylene glycol and terephthalic acid. At this time, a polymerization catalyst such as antimony or germanium may be used to promote the polymerization. Therefore, the resin sheet forming the packaging container may contain antimony and germanium, but it is considered preferable that the content and elution amount of antimony and germanium are as small as possible from the viewpoint of adverse effects on the human body. In addition, it is preferable that the packaging container is as transparent as possible from the viewpoint of checking the freshness of the food contained in the packaging container and the presence or absence of foreign matter.

[0006] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a packaging container which is less likely to adversely affect the human body and which is capable of ensuring transparency. [Means for solving the problem]

[0007] The packaging container according to the present invention includes at least one of a container body and a lid body formed of a resin sheet. The resin sheet includes a recycled polyester layer containing antimony and germanium and made of recycled polyester made of used polyester, and a virgin polyester layer containing one of antimony and germanium and not containing the recycled polyester, laminated on one or both sides of the recycled polyester layer. The overall thickness of the resin sheet is 1.0 mm or less. At least one of the container body and the lid body has an intrinsic viscosity IV value of 0.55 dl / g or more and 0.85 dl / g or less. At least one of the container body and the lid body has a haze value of less than 5.0%. The amount of antimony eluted from at least one of the container body and the lid body is more than 0 ppm and is 0.025 ppm or less. The amount of germanium eluted from at least one of the container body and the lid body is more than 0 ppm and is 0.050 ppm or less.

[0008] According to the packaging container, at least one of the container body and the lid is formed from a resin sheet having a total thickness of 1.0 mm or less, in which a virgin polyester layer is laminated on one or both sides of a recycled polyester layer, thereby suppressing the amount of elution of antimony and germanium. Here, since only one of antimony and germanium is contained in the virgin polyester layer, the amount of elution of antimony and germanium in the entire packaging container can be further suppressed. As a result, a packaging container that is less likely to have adverse effects on the human body can be provided. Furthermore, according to the packaging container, at least one of the container body and the lid is formed from the above-mentioned resin sheet, so that the haze value can be made less than 5.0%. Therefore, the transparency of the packaging container can be ensured.

[0009] According to a preferred embodiment of the present invention, the virgin polyester layer is laminated on both sides of the recycled polyester layer. The virgin polyester layer contains germanium but does not contain antimony. The amount of antimony eluted from at least one of the container body and the lid is more than 0 ppm and 0.020 ppm or less.

[0010] According to the above aspect, the virgin polyester layer contains germanium and does not contain antimony, so that the total amount of antimony contained in the entire packaging container can be reduced, and thus the amount of antimony eluted from the packaging container can be further reduced.

[0011] According to another preferred embodiment of the present invention, the virgin polyester layer is laminated on both sides of the recycled polyester layer. The virgin polyester layer contains antimony and does not contain germanium. The amount of elution of germanium contained in at least one of the container body and the lid is more than 0 ppm and 0.040 ppm or less.

[0012] According to the above aspect, the virgin polyester layer contains antimony and does not contain germanium, so that the total amount of germanium contained in the entire packaging container can be reduced, and thus the amount of germanium eluted from the packaging container can be further reduced.

[0013] According to another preferred embodiment of the present invention, the amount of germanium eluted from at least one of the container body and the lid is greater than the amount of antimony eluted.

[0014] Germanium has a higher melting point than antimony. According to the above aspect, the amount of germanium eluted is greater than the amount of antimony eluted, so that the deterioration of the heat resistance of the packaging container can be suppressed. Effect of the Invention

[0015] According to the present invention, it is possible to provide a packaging container which is unlikely to have adverse effects on the human body and which is capable of ensuring transparency. [Brief description of the drawings]

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

[0017] Hereinafter, an embodiment of the packaging container according to the present invention will be described with reference to the drawings. Note that the embodiment described here is, of course, not intended to limit the present invention. In addition, the same reference numerals are given to members and parts that perform the same function, and duplicated descriptions are omitted or simplified as appropriate.

[0018] 1 is a perspective view showing a packing container 10 according to the present embodiment. The packing container 10 is, for example, a container in which food is contained. However, the packing container 10 is not limited to a container in which food is contained.

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

[0020] The container body 11 has a bottom 12 and a side wall 13. The bottom 12 constitutes the bottom portion of the container body 11. The side wall 13 rises from the bottom 12. The side wall 13 extends upward from, for example, an end (for example, a peripheral end) of the bottom 12. The side wall 13 is arranged so as to surround the bottom 12 in a plan view. The side wall 13 may extend vertically to the bottom 12, or may extend obliquely upward from the bottom 12. In other words, the side wall 13 may be inclined so as to face outward from the bottom 12 as it moves upward away from the bottom 12. The bottom 12 and the side wall 13 may have a flat surface, or may be provided with a convex or concave portion (not shown) in order to increase rigidity, or may be provided with a so-called rib. Here, food or the like is contained in the space surrounded by the bottom 12 and the side wall 13.

[0021] In this embodiment, the bottom 12 is circular. 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 the upper end of the side wall portion 13. The container opening opens upward.

[0022] 1, the lid body 15 can be attached to the container body 11. Here, the lid body 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 body 15 is attached to the upper end of the side wall portion 13 of the container body 11 to close the container opening.

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

[0024] The fitting portion 17 is fitted to the container body 11 when the lid body 15 is attached to the container body 11. In this embodiment, the fitting portion 17 can be fitted to the upper end of the side wall portion 13 of the container body 11. The fitting portion 17 is provided at an end (e.g., a peripheral end) of the top surface portion 16 in a plan view. The fitting portion 17 is provided so as to surround the top surface portion 16 in a plan view. The fitting portion 17 is disposed at a position corresponding to the upper end of the side wall portion 13 in a state in which the lid body 15 is attached to the container body 11. The specific configuration of the fitting portion 17 is not particularly limited. The fitting portion 17 may be provided with a recess into which the upper end of the side wall portion 13 of the container body 11 is fitted, for example. The recess is provided so as to surround the top surface portion 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 body 15. The opening valve 18 is a valve through which gas or liquid flows in and out. In this embodiment, for example, the packaging container 10 may be a container that is placed in a microwave oven or the like while containing food and is heated. In this case, when the packaging container 10 is heated, steam (e.g., water vapor) is generated by heating the food. The opening valve 18 of the lid body 15 is in a closed state before being heated in the microwave oven, and when it is heated in the microwave oven, that is, when steam generated by heating the food is discharged to the outside of the lid body 15, the opening valve 18 opens and the steam passes through the opening valve 18. After the steam passes through, the opening valve 18 returns to its original closed state. Note that the number and position 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 body 15 is two. Also, the opening valve 18 is formed in the center part of the top surface 16.

[0026] The opening valve 18 has an opening 19a formed in the top surface portion 16 and a valve body 19b capable of opening and closing the opening 19a. Gas and liquid pass through the opening 19a. The valve body 19b is connected to the top surface portion 16. In this embodiment, the opening valve 18 is formed by making a cut in the top surface portion 16. The cut portion in the top surface portion 16 becomes the opening 19a and also becomes the valve body 19b. Therefore, the valve body 19b has a shape that matches the opening 19a. The shape of the valve body 19b is, for example, U-shaped. However, the shape of the valve body 19b is not particularly limited and may be, for example, C-shaped.

[0027] In this embodiment, the lid 15 is formed with the opening valve 18, but the opening valve 18 may not be formed. That is, as described above, the packaging container 10 is not limited to a container that is heated by a microwave oven or the like, but may be a container for unheated food that is not heated by a microwave oven or the like and has a lid 15 that does not have an opening valve 18. Even if the container is for unheated food, a minimum heat resistance is required to prevent deformation of the packaging container 10 during distribution in a relatively high temperature environment such as summer.

[0028] As described above, the container body 11 and the lid body 15 are formed of the resin sheet 20. Next, the resin sheet 20 will be described. The resin sheet 20 is a sheet formed of polyester (in other words, polyester resin), and is a so-called polyester sheet. The resin sheet 20 is formed of, 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, sugar cane, and beets.

[0029] Fig. 2 is a cross-sectional view of the resin sheet 20. As shown in Fig. 2, the resin sheet 20 is formed of a plurality of layers. The number of layers forming the resin sheet 20 is not particularly limited. In the following, a resin sheet 20 formed of three layers will be described.

[0030] 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.

[0031] 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 and PET trays. Recycled polyester is polyester obtained by collecting used polyester products, and is reused polyester. Also, recycled polyester is polyester obtained by collecting used polyester products based on a specified recycling method.

[0032] Here, examples of recycling methods for polyester products such as PET bottles include material recycling, chemical recycling, and mechanical recycling. Material recycling is to crush collected polyester products, wash them with alkali, and reuse them as fibers. Chemical recycling is to chemically decompose collected polyester products, return them to the raw material level, and polymerize the PET again. Mechanical recycling is to reuse collected polyester products by performing alkaline washing more strictly than in the above-mentioned material recycling, or by vacuum drying at high temperatures to reliably remove dirt from the polyester products. Here, polyester reused by mechanical recycling is called mechanically recycled polyester. In this embodiment, the regenerated polyester is, for example, mechanically recycled polyester.

[0033] The recycled polyester layer 21 may contain polyester other than recycled polyester (e.g., 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 70% by mass or more, and particularly preferably 80% by mass or more.

[0034] In addition, 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 or the packaging container 10, as long as this does not significantly impair moldability.

[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 of virgin polyester. Here, virgin polyester means 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 of recycled polyester, but is formed of unused polyester. Virgin polyester is different from recycled polyester obtained from used polyester products collected from the market.

[0036] For example, virgin polyester includes polyester derived from biomass. An example of a biomass-derived polyester is PET derived from biomass. Biomass-derived polyester refers to polyester produced using raw materials derived from plants such as corn, potatoes, sugarcane, and beets. Biomass-derived PET refers to PET produced using raw materials derived from the above plants. Virgin polyester may include polyester derived from petroleum, for example. Petroleum-derived polyester (e.g., PET) refers to polyester made from petroleum.

[0037] The virgin polyester layer 22 may contain other components besides polyester (e.g., PET) as necessary, as long as 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., lubricant MB (master batch)), antiblocking agents, flowability modifiers, plasticizers, dispersants, antibacterial agents, etc.).

[0038] In this embodiment, as shown in Fig. 2, the 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 (the upper and lower surfaces in Fig. 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 a plurality of 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 a plurality of layers (here, virgin polyester layers).

[0040] In this embodiment, the total thickness of the resin sheet 20 (in other words, the thickness of the container body 11 and the lid body 15) is 1.0 mm or less, preferably 0.3 mm or less, and particularly preferably 0.25 mm or less. Here, the thickness of the resin sheet 20 refers to the total 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 total thickness of the resin sheet 20 is 60% or more and 98% or less, preferably 65% ​​or more and 95% or less, and particularly preferably 70% or more and 92% or less. For example, the ratio of the thickness of the recycled polyester layer 21 to the virgin polyester layer 22 is recycled polyester layer:virgin polyester layer=92:8. 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 body 15) includes the inner layer 31, the outer layer 32, and the intermediate layer 33. In FIG. 2, the upper side shows the inside of the container body 11 and the lid body 15, and the lower side shows the outside of the container body 11 and the lid body 15. The inner layer 31 is the layer disposed on the innermost side among the multiple layers constituting the container body 11 and the lid body 15. The inner layer 31 is the layer constituting the inner peripheral surface of the packaging container 10. The inner layer 31 is the layer that comes into direct contact with the food when the food is contained in the packaging container 10. The outer layer 32 is the layer disposed on the outermost side among the multiple layers constituting the container body 11 and the lid body 15, and is the layer that constitutes the outer peripheral surface of the packaging container 10. The outer layer 32 is the layer that comes into direct contact with the hand, for example, when a user holds the packaging container 10 in his / her 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 directly touched by food or a 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 a plurality of 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 intermediate 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), has transparency. In other words, the recycled polyester layer 21 and the virgin polyester layer 22 have transparency. 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%, and particularly preferably less than 2.0%.

[0045] In this embodiment, the haze value of the recycled polyester layer 21 is 1.9% or less, preferably 1.8% or less, and particularly preferably 1.7% or less. The haze value of the virgin polyester layer 22 is 1.8% or less, preferably 1.7% or less, and particularly preferably 1.6% or less.

[0046] 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 0.85 dl / g or less, preferably 0.57 dl / g or more and 0.83 dl / g or less, and particularly preferably 0.59 dl / g or more and 0.81 dl / g or less.

[0047] Next, a procedure for producing the resin sheet 20 and the packaging container 10 according to this embodiment will be described. Here, pellets are prepared and extrusion molding is performed on the pellets to produce the resin sheet 20. Then, the resin sheet 20 is thermoformed to produce the packaging container 10, i.e., the container body 11 and the lid 15.

[0048] Here, pellets are prepared first. In this embodiment, virgin pellets made of virgin polyester and recycled pellets made of recycled polyester are prepared as the pellets. 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 containers such as used PET bottles and used PET trays. Here, the recycled pellets are made by crushing used polyester products collected from the market, removing foreign matter, washing, and drying.

[0049] Next, the virgin pellets and the recycled pellets are extrusion molded to produce a resin sheet 20. FIG. 3 is a schematic diagram of an extrusion device 50 used in extrusion molding. In this embodiment, the extrusion device 50 shown in FIG. 3 is used in 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 joining die 53, a cooling roll 54, and a winder 55.

[0050] In this embodiment, the first hopper 51A and the first screw 52A are for virgin pellets (hereinafter referred to as for virgin). The second hopper 51B and the second screw 52B are for recycled pellets (hereinafter referred to as for 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. In addition, 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.

[0051] In the extrusion molding, the virgin pellets 40A are first put into the first hopper 51A. In the virgin use, the virgin pellets 40A put into the first hopper 51A are made to flow into the first screw 52A, and mixed by the rotation of the first screw 52A while being heated by the first heater 57A. The virgin pellets 40A mixed by the first screw 52A are made to flow toward the narrow feed block 58. Similarly, in the regeneration use, the regeneration pellets 40B are put into the second hopper 51B. The regeneration pellets 40B put into the second hopper 51B are made to flow into the second screw 52B, and mixed by the rotation of the second screw 52B while being heated by the second heater 57B. The regeneration pellets 40B mixed by the second screw 52B are made to flow toward the feed block 58.

[0052] In the feed block 58, the virgin pellets 40A and the recycled pellets 40B join together and are made to flow into the joining die 53. In the joining die 53, a layer of the virgin pellets 40A and a layer of the recycled pellets 40B are extruded (here, co-extruded) by the feed block 58 and discharged. Here, the layer of the 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 the recycled pellets 40B extruded from the joining die 53 by the feed block 58 becomes the recycled polyester layer 21 (see FIG. 2).

[0053] In this embodiment, although detailed illustration is omitted, the virgin polyester layer 22, the recycled polyester layer 21, and the virgin polyester layer 22 are stacked in this order in a heated state 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.

[0054] 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, since the resin sheet 20 discharged from the confluence die 53 is in a heated state, 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.

[0055] Next, 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 of a mold 60 and a plug 65 used in thermoforming. As shown in FIG. 4, a mold 60 and a plug 65 are used in thermoforming. A recess 61 is formed in the mold 60. A protrusion 66 is formed in the plug 65 to be inserted into the recess 61 of the mold 60. Here, during thermoforming, the mold 60 and the plug 65 are arranged in a spaced apart state so that the recess 61 and the protrusion 66 face each other. Then, the heated resin sheet 20 is arranged between the mold 60 and the plug 65. At this time, the resin sheet 20 is arranged 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.

[0056] 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.

[0057] 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.

[0058] In the present embodiment, the packaging container 10 (here, the container body 11 and the lid body 15) contains antimony and germanium. Here, the recycled polyester layer 21 constituting the resin sheet 20 contains antimony and germanium. The virgin polyester layer 22 constituting the resin sheet 20 contains one of antimony and germanium. That is, the virgin polyester layer 22 may contain antimony but not germanium. Alternatively, the virgin polyester layer 22 may contain no antimony but germanium.

[0059] The PET resin used in the packaging container 10 according to this embodiment is produced by polymerizing ethylene glycol and terephthalic acid. In this case, a so-called polymerization catalyst may be used to promote the polymerization of ethylene glycol and terephthalic acid. Examples of the polymerization catalyst include antimony and germanium as described above. In this embodiment, the recycled polyester layer 21 and the virgin polyester layer 22 of the resin sheet 20 are produced from PET resin pellets produced by appropriately using antimony and germanium as polymerization catalysts.

[0060] However, antimony and germanium, which are examples of polymerization catalysts, are known to have adverse effects on the human body when ingested in large quantities, and it is preferable that the amount of elution of antimony and germanium is as small as possible. Here, the amount of elution refers to the amount of antimony and the amount of germanium when antimony and germanium are used as polymerization catalysts, a solvent such as acetic acid is filled in the packaging container 10, and a heat elution test is performed. It is considered that the amount of elution becomes relatively larger as the amount of antimony and germanium used during polymerization increases.

[0061] As in the present embodiment, the industry that manufactures packaging containers 10 is actively working to reduce the environmental impact. One example of this is the effort to collect used PET bottles from the market, crush them, wash them, and repolymerize them, and reuse them as a recycled polyester layer 21 containing recycled polyester. Polymerization catalysts such as antimony and germanium are used in the repolymerization after collecting used PET bottles as described above, but are also used in producing a virgin polyester layer 22 containing virgin polyester.

[0062] When preparing the virgin polyester layer 22 containing virgin polyester, a single polymerization step is performed, but when preparing the recycled polyester layer 21 containing recycled polyester (particularly, recycled polyester by chemical recycling), recycled polyester that has undergone at least two polymerization steps is used. The more polymerization steps are performed, the higher the concentration of the polymerization catalyst is likely to be (e.g., the more the amount of elution is likely to be), and there is a risk that the recycled polyester contained in the recycled polyester layer 21 of the packaging container 10 cannot be used. Therefore, in this embodiment, the amount of elution of polymerization catalysts such as antimony and germanium is suppressed by laminating the virgin polyester layers 22 on both sides of the recycled polyester layer 21 during extrusion molding.

[0063] In this embodiment, the amount of antimony eluted from the packaging container 10, i.e., the container body 11 and the lid body 15, is more than 0 ppm and 0.025 ppm or less, preferably more than 0 ppm and 0.023 ppm or less, and particularly preferably more than 0 ppm and 0.020 ppm or less. The amount of germanium eluted from the packaging container 10, i.e., the container body 11 and the lid body 15, is more than 0 ppm and 0.050 ppm or less, preferably more than 0 ppm and 0.045 ppm or less, and particularly preferably more than 0 ppm and 0.040 ppm or less. In this embodiment, the amount of germanium eluted from the packaging container 10, i.e., the container body 11 and the lid body 15, is greater than the amount of antimony eluted from the container body 11 and the lid body 15.

[0064] For example, when the virgin polyester layer 22 does not contain antimony but contains germanium, the amount of antimony contained in the entire packaging container 10 is relatively reduced. Therefore, the amount of antimony eluted in the packaging container 10 is reduced, for example, more than 0 ppm and 0.020 ppm or less. On the other hand, when the virgin polyester layer 22 does not contain germanium but contains antimony, the amount of germanium contained in the entire packaging container 10 is relatively reduced. Therefore, the amount of germanium eluted in the packaging container 10 is reduced, for example, more than 0 ppm and 0.040 ppm or less.

[0065] Incidentally, even the packaging container 10 made using recycled polyester as in this embodiment is required to have physical properties equivalent to those of a packaging container made using only virgin polyester. For example, recycled polyester made from used PET bottles collected from the market is produced through processes such as crushing, washing, and repolymerization after collecting the PET bottles, as described above. In these processes, there is a risk that physical properties such as strength and heat resistance of the recycled polyester layer 21 containing recycled polyester will decrease due to hydrolysis, thermal degradation, etc.

[0066] In addition, since the packaging container 10 made using recycled polyester reuses scraps generated during the manufacturing process, repeated application of heat to the recycled polyester can cause a decrease in performance due to thermal degradation. Furthermore, repeated application of heat to the recycled polyester can easily cut and shorten the molecular chains that make up the resin. The shortened molecular chains can easily move due to external heat. As a result, the melting point of the recycled polyester can be lowered, and the heat resistance can be reduced.

[0067] Therefore, the applicant of the present application has focused on the polymerization catalysts antimony and germanium and studied the relationship between the polymerization catalyst and heat resistance. For example, when producing a recycled polyester layer 21 containing recycled polyester and a virgin polyester layer 22 containing virgin polyester, antimony can be used as a polymerization catalyst that is low cost and has excellent polymerization activity. However, since antimony can have an adverse effect on the human body if ingested in large amounts, a polymerization catalyst that can replace antimony is required.

[0068] Germanium can be used as a polymerization catalyst to replace antimony. Germanium is thought to have the same polymerization activity as antimony. In addition, the melting point of germanium is about 938 degrees, which is higher than the melting point of antimony, which is about 630 degrees, so it is expected that germanium will suppress the deterioration of heat resistance.

[0069] From the above, it is expected that the melting point will be high by producing a recycled polyester layer 21 (for example, a packaging container 10) containing germanium, which has a high melting point. Therefore, as in this embodiment, by producing the container body 11 and the lid body 15 of the packaging container 10 using a recycled polyester layer 21 containing germanium, it is possible to provide a packaging container 10 that can suppress a decrease in heat resistance. Also, as in this embodiment, it is considered that the amount of elution of germanium contained in the packaging container 10 is greater than the amount of elution of antimony contained in the packaging container 10, and therefore the decrease in heat resistance of the packaging container 10 can be suppressed.

[0070] Next, an evaluation experiment was conducted to evaluate the packaging container 10 according to this embodiment. Here, the following packaging containers, Samples 1 to 3, were prepared for the evaluation test. In Samples 1 to 3, the thickness of the resin sheet was 0.25 mm. In addition, in Samples 1 to 3, the size of the container body of the packaging container was 244 mm in length, 171 mm in width, and 16 mm in height.

[0071] <Sample 1> Sample 1 is a packaging container formed from the resin sheet according to the present embodiment. In Sample 1, the thickness ratio of the inner layer, intermediate layer, and outer layer in the packaging container (hereinafter also referred to as layer ratio) is inner layer: intermediate layer: outer layer = 4: 92: 4.

[0072] The recycled polyester layer (here, the middle layer) in Sample 1 is composed of virgin polyester and recycled polyester, containing 20 mass% virgin polyester and 80 mass% recycled polyester. The virgin polyester layers (here, the inner layer and the outer layer) in Sample 1 are composed of virgin polyester and lubricant MB (master batch), containing 94 mass% virgin polyester and 6 mass% lubricant MB.

[0073] In sample 1, flakes obtained by crushing PET bottles collected from the market (i.e., discarded PET bottles) were used as the recycled polyester. Here, the flakes obtained by crushing discarded PET bottles were washed with a washing solution containing caustic soda at a temperature of 85 degrees for 30 minutes. After that, an aqueous phosphoric acid solution was added to the washed flakes to perform a neutralization treatment. Furthermore, the residual chemicals contained in the flakes were removed using pure water. Next, the above flakes were pelletized using a twin-screw extruder (twin-screw extruder with a temperature set to about 290 degrees) equipped with a vent-type volatile matter removal device. The pellets thus obtained were pre-crystallized, and then polymerized for 5 minutes using a solid-phase polymerization device set to 200 degrees under a nitrogen stream to produce recycled polyester.

[0074] The virgin polyester of sample 1 was a PET resin "YS-H01" manufactured by Hainan Yisheng Petrochemical Co., Ltd. of China. The intrinsic viscosity IV value of this virgin polyester was 0.78 dl / g. The lubricant MB of sample 1 was "RE555" manufactured by Toyobo Co., Ltd. The lubricant MB used was a polyester resin containing fine particles obtained by mixing 7000 ppm of spherical silica having an average particle size of 2.4 μm during polymerization with a polyester resin having an intrinsic viscosity IV value of 0.62 dl / g (see JP 2008-30282 A).

[0075] In sample 1, the resin sheet and packaging container were prepared 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 were mixed to prepare a mixture for the recycled polyester layer.

[0076] Thereafter, extrusion molding was performed using a twin-screw extruder (here, extrusion device) of model "SBIN-42-S2-30-L" manufactured by Plastics Engineering 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 about 0.20 mm to 0.80 mm.

[0077] Next, the above resin sheet was subjected to vacuum and pressure forming to produce a packaging container of Sample 1.

[0078] <Sample 2> The packaging container of Sample 2 is a packaging container that has the same configuration and is produced by the same production procedure as Sample 1, except that the ratio of virgin polyester to recycled polyester in the middle layer of the packaging container is different. In Sample 2, the middle layer of the packaging container contains 50% by mass of virgin polyester and 50% by mass of recycled polyester.

[0079] <Sample 3> The packaging container of Sample 3 does not include an inner layer or an outer layer in the resin sheet produced by extrusion molding. The packaging container of Sample 3 is a packaging container produced by 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 recycled polyester layer, which has a different ratio of virgin polyester and recycled polyester from Sample 1. In Sample 3, the resin sheet is constituted of a recycled polyester layer containing 0 mass % virgin polyester and 100 mass % recycled polyester.

[0080] The thickness, layer ratio, and composition of the resin sheets in Samples 1 to 3 are shown in Table 1 below.

[0081] [Table 1]

[0082] Here, the intrinsic viscosity IV value (dl / g) of the packaging container (here, the container body and the lid) of the packaging containers of Samples 1 to 3 was measured in accordance with JIS K7367-5. Here, 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 3 are shown in Table 1 above.

[0083] Next, a transparency evaluation test was conducted on the packaging containers of Samples 1 to 3. In the transparency evaluation test, the total light transmittance (Tt) (%) and the diffuse transmittance (Td) (%) were measured for the packaging containers of Samples 1 to 3 in accordance with JIS K7136. Then, the measured total light transmittance and diffuse transmittance were used to calculate the haze value (%) of the packaging container (here, the container body and the lid). The haze value is calculated, for example, using the formula 100×Td / Tt. The haze values ​​for the packaging containers of Samples 1 to 3 are shown in Table 1 above. Note that the lower the haze value, the better the transparency.

[0084] Next, the antimony and germanium elution test was performed on the packaging containers of Samples 1 to 3. Here, the packaging containers of Samples 1 to 3 were filled with a 4% acetic acid solution, and the elution test was performed for 30 minutes in an environment of 60 degrees, and analyzed with a frameless atomic absorption spectrophotometer (type: ICP-MS). The analysis obtained the total amount of eluted antimony and germanium from the packaging containers of Samples 1 to 3. Furthermore, the surface (surface layer = inner layer or outer layer) of the packaging containers of Samples 1 to 3 was thinly sliced ​​using a microtome having a knife formed of glass or diamond. The sliced ​​members were analyzed using the above-mentioned frameless atomic absorption spectrophotometer, and the amount of eluted antimony and germanium from the surface (surface layer = inner layer or outer layer) of the packaging containers of Samples 1 to 3 was obtained. The amounts of antimony and germanium eluted from the entire packaging containers of Samples 1 to 3 and the amounts of antimony and germanium eluted from the surfaces (surface layer = inner layer or outer layer) of the packaging containers of Samples 1 to 3 are shown in Table 1 above.

[0085] In the case of packaging containers in which virgin polyester layers were laminated on both sides of a recycled polyester layer, as in samples 1 and 2, the amount of antimony eluted was 0.025 ppm or less, and the amount of germanium eluted was 0.050 ppm or less, both in the entire packaging container and on the surface (surface layer = inner layer or outer layer). Therefore, the amounts of antimony and germanium eluted were relatively small in samples 1 and 2. On the other hand, in the case of a packaging container formed only from a recycled polyester layer, as in sample 3, the amount of antimony eluted was more than 0.025 ppm, and the amount of germanium eluted was more than 0.050 ppm, both in the entire packaging container and on the surface (surface layer = inner layer or outer layer). Therefore, the amounts of antimony and germanium eluted were relatively large in sample 3. This shows that the amount of antimony and germanium eluted can be suppressed by forming a packaging container from a resin sheet in which a recycled polyester layer and a virgin polyester layer are laminated.

[0086] In addition, in Samples 1 and 2, the amount of germanium eluted from the surface (surface layer = inner layer or outer layer) of the packaging container was 0, and germanium was not detected. From this, it is presumed that in Samples 1 and 2, the virgin polyester layers forming the inner and outer layers did not contain germanium, but contained antimony.

[0087] Moreover, in Samples 1 and 2, the haze value was about 1.5%, which was lower than that of Sample 3. This shows that transparency can be ensured by forming a packaging container from a resin sheet in which a recycled polyester layer and a virgin polyester layer are laminated.

[0088] As described above, in this embodiment, as shown in FIG. 1, the packaging container 10 includes both the container body 11 and the lid body 15 formed by the resin sheet 20. As shown in FIG. 2, the resin sheet 20 includes a recycled polyester layer 21 containing antimony and germanium and containing recycled polyester made of used polyester, and a virgin polyester layer 22 containing one of antimony and germanium and not containing recycled polyester, laminated on both sides of the recycled polyester layer 21. The overall thickness of the resin sheet 20 is 1.0 mm or less. The intrinsic viscosity IV value of the container body 11 and the lid body 15 is 0.55 dl / g or more and 0.85 dl / g or less. The haze value of the container body 11 and the lid body 15 is less than 5.0%. The amount of elution of antimony contained in the container body 11 and the lid body 15 is more than 0 ppm and 0.025 ppm or less. The amount of elution of germanium contained in the container body 11 and the lid body 15 is more than 0 ppm and 0.050 ppm or less. In this manner, in this embodiment, the container body 11 and the lid 15 are formed from the resin sheet 20 having a total thickness of 1.0 mm or less, in which the virgin polyester layer 22 is laminated on both sides of the recycled polyester layer 21, and the amount of elution of antimony and germanium can be suppressed. Here, since the virgin polyester layer 22 contains only one of antimony and germanium, the amount of elution of antimony and germanium in the entire packaging container 10 can be further suppressed. As a result, it is possible to provide a packaging container 10 that is less likely to adversely affect the human body. Furthermore, in this embodiment, the container body 11 and the lid 15 are formed from the resin sheet 20 having the virgin polyester layer 22 laminated on both sides of the recycled polyester layer 21, and the haze value can be made less than 5.0%. Therefore, the transparency of the packaging container 10 can be ensured.

[0089] In this embodiment, the virgin polyester layer 22 may contain germanium but not antimony. In this case, the amount of antimony eluted from the container body 11 and the lid 15 is greater than 0 ppm and equal to or less than 0.020 ppm. In this way, by making the virgin polyester layer 22 contain germanium but not antimony, the total amount of antimony contained in the entire packaging container 10 can be reduced. Therefore, the amount of antimony eluted from the packaging container 10 (specifically, the container body 11 and the lid 15) can be further reduced.

[0090] In this embodiment, the virgin polyester layer 22 may contain antimony and may not contain germanium. In this case, the amount of elution of germanium contained in the container body 11 and the lid body 15 is more than 0 ppm and is 0.040 ppm or less. In this way, by making the virgin polyester layer 22 contain antimony and not contain germanium, the total amount of germanium contained in the entire packaging container 10 can be reduced. Therefore, the amount of elution of germanium in the packaging container 10 can be further reduced.

[0091] In this embodiment, the amount of elution of germanium contained in the container body 11 and the lid body 15 (here, the entire packaging container 10) is greater than the amount of elution of antimony contained in the container body 11 and the lid body 15 (here, the entire packaging container 10). As described above, germanium has a higher melting point than antimony. Therefore, by making the amount of elution of germanium greater than the amount of elution of antimony, it is possible to suppress a decrease in the heat resistance of the packaging container 10.

[0092] 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 sides of the wide surface of the recycled polyester layer 21, and the number of the 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 the virgin polyester layers 22 may be one. In this case, the outer layer 32 may be omitted in the lid 15 of the packaging container 10. [Explanation of symbols]

[0093] 10 Packaging containers 11 Container body 15 Lid 20 Resin sheet 21 Recycled polyester layer 22 virgin polyester layer

Claims

1. The container has at least one of a container body and a lid body formed of a resin sheet, The resin sheet is a recycled polyester layer containing antimony and germanium and containing recycled polyester made from used polyester; a virgin polyester layer laminated on one or both sides of the recycled polyester layer, the virgin polyester layer containing one of antimony and germanium and not containing the recycled polyester; having The resin sheet has a total thickness of 1.0 mm or less, At least one of the container body and the lid has an intrinsic viscosity IV value of 0.55 dl / g or more and 0.85 dl / g or less; At least one of the container body and the lid has a haze value of less than 5.0%, The amount of antimony eluted from at least one of the container body and the lid is greater than 0 ppm and is 0.025 ppm or less; A packaging container, in which an amount of elution of germanium contained in at least one of the container body and the lid is greater than 0 ppm and less than or equal to 0.050 ppm.

2. The virgin polyester layer is laminated on both sides of the recycled polyester layer, the virgin polyester layer contains germanium and is free of antimony; 2. The packaging container according to claim 1, wherein an amount of antimony eluted from at least one of said container body and said lid is greater than 0 ppm and is 0.020 ppm or less.

3. The virgin polyester layer is laminated on both sides of the recycled polyester layer, the virgin polyester layer contains antimony and is free of germanium; 2. The packaging container according to claim 1, wherein an amount of eluted germanium contained in at least one of said container body and said lid is more than 0 ppm and 0.040 ppm or less.

4. 2. The packaging container according to claim 1, wherein an amount of germanium eluted from at least one of said container body and said lid is greater than an amount of antimony eluted from said container body and / or said lid.

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