Laminated sheet for container, and container

Abstract

To provide a laminate sheet 1 for a container, having a beautiful external appearance, protecting a content thereof from light beams irradiated from outside, and having an inspection suitability for a metal inspection machine, with a light shielding layer of the laminate sheet 1 not including a metal foil, and also to provide a container 50 formed at least from the laminate sheet 1.SOLUTION: A laminate sheet 1 for a container includes, at least from outside: an outer film layer 11 having a hiding layer 12; a separation layer 20; and a paper substrate layer 31 having a light shielding layer 32.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate sheet for a container having light-blocking properties, and also to a container comprising at least the laminate sheet for a container. [Background technology]

[0002] Conventionally, a laminated sheet for containers has been disclosed in Patent Document 1. The laminated sheet for containers contains aluminum foil with light-blocking properties. Furthermore, Patent Document 2 discloses a liquid container made of a laminated sheet for a container that includes aluminum foil having light-shielding properties and paperboard.

[0003] However, in recent years, the safety of food and other products has become increasingly important, and there is a demand to inspect containers that package their contents (hereinafter referred to as container packages) to prevent the inclusion of foreign matter. In order to inspect all container packages, non-destructive inspection is effective as it allows inspection without destroying the container packages.

[0004] One example of such non-destructive testing is a metal detector that can detect metallic foreign objects present inside a container package. In order to improve the accuracy of this testing, it is desirable that the container does not contain metal foil (in most cases, aluminum foil is used due to its workability and cost). If a metal foil is present, there is a risk that the detection of metallic foreign matter may be hindered by the metal foil, but if there is no metal foil, the detection of metallic foreign matter is not hindered, and the accuracy of metal detection increases. An example of a method for metal detection is X-ray inspection.

[0005] Furthermore, the contents of the container package may deteriorate due to exposure to external light (ultraviolet rays, visible light, etc.). To prevent this deterioration, the container may be provided with a light-blocking layer, which is a layer that blocks light, and this light-blocking layer is often aluminum foil. Furthermore, since the light-shielding layer is visible from the outside, it may overlap with the design of the container, deteriorating the design.

[0006] However, there are cases where a container is required to have both metal detector-compatible properties and light-blocking properties, and further, there are cases where the container is required to have an aesthetically pleasing appearance. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-80631 [Patent Document 2] Japanese Utility Model Application Publication No. 1-78514 Summary of the Invention [Problem to be solved by the invention]

[0008] The present disclosure has been made to solve the above-mentioned problems, and its object is to provide a laminated sheet for containers that has light-blocking properties without containing metal foil. Furthermore, the present invention aims to provide a container made of the laminated sheet for the container. [Means for solving the problem]

[0009] The above problems can be solved by the following embodiments of the present disclosure. That is, the laminated sheet 1 for a container according to the present disclosure is An outer laminated portion 10 including at least an outer film layer 11 having a concealing layer 12 from the outside; a spacing layer 20; and an inner laminate portion 30 including a paper substrate layer 31 with a light-shielding layer 32.

[0010] The laminate sheet 1 for containers of the present disclosure may have a total light transmittance of 2% or less.

[0011] The laminate sheet 1 for containers of the present disclosure may have an ISO whiteness of 70% or more on the outer surface.

[0012] In the laminated sheet for containers 1 of the present disclosure, the light-shielding layer 32 may be a printed layer.

[0013] In the laminated sheet for containers 1 of the present disclosure, the light-shielding layer 32 may be provided on the outside of the paper base layer 31 .

[0014] The laminated sheet 1 for a container according to the present disclosure comprises: The outer film layer 11 may be see-through, and the opacifying layer 12 may be provided inside the outer film layer 11 .

[0015] The laminated sheet 1 for a container according to the present disclosure comprises: The concealing layer 12 may include a base concealing layer 122 at least on the spacing layer 20 side.

[0016] In the laminate sheet 1 for a container of the present disclosure, the basic concealing layer 122 may be white.

[0017] In the laminate sheet 1 for a container of the present disclosure, the concealing layer 12 may be a printed layer.

[0018] The laminate sheet 1 of the present disclosure is The basic concealing layer 122 of the concealing layer 12 may be a background pattern print.

[0019] In the laminated sheet 1 for a container of the present disclosure, the spacing layer 20 may be an adhesive layer.

[0020] In the laminated sheet 1 for a container of the present disclosure, the spacing layer 20 may be a synthetic resin layer.

[0021] The laminated sheet 1 for a container according to the present disclosure comprises: The spacing layer 20 may be an extrusion laminated synthetic resin layer.

[0022] In the laminated sheet 1 for a container of the present disclosure, the spacing layer 20 may be white.

[0023] In the laminated sheet 1 for a container of the present disclosure, the spacing layer 20 may be see-through.

[0024] The container 50 of the present disclosure may be made up of at least the laminated sheet 1.

[0025] The container 50 of the present disclosure may be a paper container 51.

[0026] The paper container 51 of the present disclosure may be a paper cup 52.

[0027] The paper container 51 of the present disclosure may be a gable-top liquid paper container 53.

[0028] The paper container 51 of the present disclosure may be a rectangular parallelepiped (brick-shaped) paper container 54 for liquid. [Effects of the Invention]

[0029] According to the above-described embodiment of the present disclosure, a laminated sheet 1 for containers that does not contain metal foil and has light-blocking properties is provided. That is, a laminated sheet 1 for containers is provided that has two properties: light-blocking property and metal detectability. Furthermore, the concealing layer 12 makes the light-shielding layer 32 less visible when viewed from the outside, providing a laminated sheet 1 for containers with a beautiful appearance. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a cross-sectional view of a laminate sheet for a container according to a first embodiment of the present disclosure. [Figure 2A] 2 is an enlarged view of part A of the first embodiment of the laminated sheet for a container shown in FIG. 1. FIG. [Figure 2B] 2 is an enlarged view of part A of a second embodiment of the laminated sheet for a container shown in FIG. 1. FIG. [Figure 3A] FIG. 2 is a cross-sectional view of a laminate sheet for a container according to a second embodiment of the present disclosure. [Figure 3B]FIG. 10 is a cross-sectional view of a laminate sheet for a container according to a third embodiment of the present disclosure. [Figure 4A] FIG. 1 is a perspective view of a paper cup using a laminate sheet for a container according to the present disclosure. [Figure 4B] FIG. 1 is a perspective view of a gable-top paper container for liquids using a laminate sheet for a container of the present disclosure. [Figure 4C] FIG. 1 is a perspective view of a rectangular (brick-shaped) paper container for liquids that uses a laminate sheet for containers according to the present disclosure. [Figure 5] FIG. 1 is a cross-sectional view of a laminated sheet for a container according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present disclosure will be described below with reference to the drawings, but the present disclosure is not limited to the specifically illustrated embodiments or various specifically described structures. In each drawing, the size and proportions of the components may be changed or exaggerated for ease of understanding. Also, for clarity, unnecessary parts and repeated reference numerals may be omitted.

[0032] Furthermore, the numerical values such as dimensions of each member and the names of materials described in this specification are examples of embodiments, and are not limited to these, and may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include not only their strict meanings but also substantially the same state.

[0033] <First aspect of the first embodiment> A cross-sectional view of a laminate sheet 1 for a container of this embodiment is shown in Fig. 1. Further, enlarged views of part A in Fig. 1 are shown in Fig. 2A and Fig. 2B. Fig. 2A shows a first embodiment of this embodiment, and Fig. 2B shows a second embodiment of this embodiment, which will be described later.

[0034] The left side of the laminated sheet 1 for a container shown in FIG. 1 becomes the outside when a container 50 (described later) is produced, and the right side becomes the inside. In the laminated sheet 1 for a container, the side that will become the outside when the above-mentioned container 50 is produced may be called the front side, and the side that will become the inside may be called the back side.

[0035] The layer structure of the laminated sheet 1 for containers will be described. The container laminate sheet 1 includes an outer laminate portion 10, a separation layer 20, and an inner laminate portion 30 in this order from the front side (the left side in FIG. 1). As will be described in detail later, each layer may be a single layer or multiple layers. In addition, other layers may be included on the outer surface of each layer described above and between layers, as long as the function is not impaired.

[0036] A description will be given of the inner laminated portion 30, which forms the inside of the container laminated sheet 1. In this embodiment, the inner laminated portion 30 includes, from the outside, a light-shielding layer 32, a paper base layer 31, and an inner synthetic resin layer 33.

[0037] The light-shielding layer 32 has the function of blocking light rays that enter from outside the container 50. Therefore, the light rays are blocked and do not reach the contents, preventing deterioration of the contents due to light rays. In particular, blocking ultraviolet rays and visible light is highly effective in preventing deterioration of the contents. The light-shielding layer 32 can be formed, for example, by using a metal foil such as aluminum foil, a synthetic resin layer having light-shielding properties, a coating layer having light-shielding properties, or printing.

[0038] Furthermore, in the container 50 of the present disclosure, if the container is to be inspected with a metal detector during manufacturing or after filling the container with contents, it is not appropriate to use aluminum foil for the light-shielding layer 32. Furthermore, it may be preferable not to use aluminum foil in order to eliminate aluminum foil residue (burnt remains) when the container 50 is incinerated after use. Therefore, the present disclosure provides a light-shielding layer 32 that does not use aluminum foil.

[0039] The light-shielding layer 32, which does not use aluminum foil, is provided on the front side of the paper base layer 31. In this embodiment, black printing is provided on the front side of the paper base layer 31, and the black printing provides light-shielding properties. The color of the printing on the light-shielding layer 32 may be a dark color instead of black. Hereinafter, when the light-shielding layer 32 is described as black, it will also include a dark color.

[0040] In this embodiment, black gravure printing is used to print the light-shielding layer 32. By printing using gravure printing, the light-shielding layer 32 can be provided at low cost.

[0041] The paper base layer 31 provides rigidity to the container 50, and has rigidity (firmness). To obtain appropriate rigidity with a synthetic resin layer, a thickness of 500 μm or more is generally required, which increases the amount of synthetic resin used and is unfavorable for the environment. If the paper base layer 31 can provide rigidity, the amount of synthetic resin used can be reduced, which is environmentally friendly. Paper used includes white cardboard, manila cardboard, cup base paper, milk carton base paper, cardboard, ivory paper, etc.

[0042] The inner synthetic resin layer 33 provided on the inside of the paper base layer 31 may be used to join inner synthetic resin layers 33 together when manufacturing the container 50, or to join the inner synthetic resin layer 33 to the outer synthetic resin layer 13 described later. The inner synthetic resin layer 33 also has the function of preventing the contents from permeating into the laminated sheet 1 for containers and from leaking out of the container 50. These functions will be described in detail later.

[0043] The inner synthetic resin layer 33 is made of, for example, a thermoplastic resin, and one of its functions is adhesiveness. In this case, the inner synthetic resin layer 33 may be thermoplastic and may be bonded by heating. Examples of materials that may be used for the outer synthetic resin layer 13 and the inner synthetic resin layer 33 include low-density polyethylene (hereinafter sometimes abbreviated as LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-α-olefin copolymers polymerized using a single-site catalyst, ethylene-vinyl acetate copolymers (EVA), ethylene-acrylic acid copolymers (EAA), ethylene-methacrylic acid random copolymers (EMAA), ethylene-methyl acrylate copolymers (EMA), ethylene-ethyl acrylate copolymers (EEA), ionomers, polypropylene and its copolymers, polyester-based resins, and the like.

[0044] Another function of the inner synthetic resin layer 33 is antifouling. It is effective in preventing water-based or oil-based foreign matter from penetrating into the laminate sheet for containers 1. In particular, since the laminate sheet for containers 1 of this embodiment includes the paper base layer 31, it is preferable that the layer 33 be able to prevent the penetration of water-based or oil-based liquids or liquid foreign matter. This is because if the above foreign matter penetrates the paper base layer 31, it will appear as a stain that is easily visible.

[0045] If the only function required for the container 50 is antifouling property and thermal adhesiveness is not required, the inner synthetic resin layer 33 may or may not be thermoplastic (thermal adhesive).

[0046] If the inner synthetic resin layer 33 does not have thermal adhesive properties, the container 50 may be manufactured using a pressure sensitive adhesive, adhesive, or the like. Alternatively, the container 50 may be used for a container that does not have any joints (for example, a box that is fixed and assembled by mechanical engagement).

[0047] Next, a description will be given of the outer laminate portion 10. In this embodiment, the outer laminate portion 10 includes an outer synthetic resin layer 13, an outer film layer 11, and a concealing layer 12 in this order from the outside.

[0048] The functions of the outer synthetic resin layer 13 are thermal adhesiveness and stain resistance, similar to those of the inner synthetic resin layer 33. The description of the outer synthetic resin layer 13 is omitted here because it is similar to that of the inner synthetic resin layer 33.

[0049] When the only function required of the outer synthetic resin layer 13 is antifouling property, the outer synthetic resin layer 13 may or may not have thermoplastic properties (thermoadhesive properties). If the outer synthetic resin layer 13 does not have thermal adhesive properties, the container 50 may be made using an adhesive. Alternatively, the container 50 may be used for a container to which the outer synthetic resin layer 13 is not glued (for example, a flat pouch shape). Furthermore, the container 50 may be used for a container to which no joints exist (for example, a box that is assembled by mechanical engagement).

[0050] The outer film layer 11 does not necessarily have to be thermally adhesive, and may be a strong film. Examples include polyethylene terephthalate film (hereinafter referred to as PET film), nylon film, and polypropylene film. The above films may be uniaxially or biaxially stretched.

[0051] The concealing layer 12 is provided to make the light-shielding layer 32 of the inner laminated portion 10 less visible from the outside of the laminated sheet for containers 1. The light-shielding layer 32 may be black to reduce the total light transmittance of the laminated sheet for containers 1, and if that color is visible from the outside, the design may be impaired, so the concealing layer 12 is provided to prevent this.

[0052] The concealing layer 12 will be described with reference to Fig. 2A, which is an enlarged view of part A in Fig. 1. Fig. 2A shows a laminated sheet 1 for a container according to a first aspect of this embodiment, in which the concealing layer 12 includes a display layer 121 such as a pattern and a base concealing layer 122, and the display layer 121 such as a pattern and the base concealing layer 122 are provided in this order inside the outer film layer 11.

[0053] Pictures, letters, various codes, etc. are printed on the picture display layer 121. In this case, printing is performed directly on the see-through outer film layer 11, so that the printed pictures, etc. can be seen from the outside through the outer film layer 11.

[0054] When a vivid design is applied to the display layer 121 such as a pattern, it is preferable that the black light-shielding layer 32 is not visible when viewed from the outside in order to improve the vividness of the design. For this purpose, the basic concealing layer 122 is provided, and the basic concealing layer 122 may be printed directly on the inside of the display layer 121 such as a pattern. If the basic concealing layer 122 is white, the display layer 121 such as a pattern will be visible vividly. In this case, the basic concealing layer 122 may be printed in white over substantially the entire surface of the laminated sheet 1 for containers.

[0055] Depending on the design of the pattern display layer 121, the basic concealing layer 122 may be a single color other than white, and may also be a background pattern print that is a continuous pattern. In any case, the basic concealing layer 122 may be a monochromatic or patterned print, or a print with a design, as appropriate. However, in order to achieve concealing properties, it may be printed over almost the entire surface (solid printing).

[0056] In the above example, the basic concealing layer 122 of the concealing layer 12 is formed by printing. However, the basic concealing layer 122 may be a synthetic resin layer having concealing properties instead of printing, and the synthetic resin layer may be colored white or another color. Furthermore, a metal vapor-deposited film, such as an aluminum vapor-deposited film, which combines glossiness and hiding properties, may be used for the basic hiding layer 122 .

[0057] Since the outer film layer 11 is see-through, the pattern or other display layer 121 can be seen from the outside. In order to make the pattern or other display layer 121 more clearly visible, the outer film layer 11 should be as close to colorless and transparent as possible, and a PET film is suitable in terms of transparency, processability, and economy.

[0058] Furthermore, when printing on a paper container 51 whose base layer is a paper base layer 31, a pattern or the like may be printed on the outside of the paper base layer 31. The surface texture of the paper base layer 31 is often rougher than that of a synthetic resin film, and therefore the expression of fine print may be inferior. With the paper container 51 of the present disclosure, printing is performed on the inner surface of the outer film layer 11, which has a smooth surface texture, making it possible to produce fine prints.

[0059] The spacing layer 20 will now be described. The separating layer 20 is a synthetic resin layer provided between the concealing layer 12 and the light-shielding layer 32. The presence of the separating layer 20 has the effect of making the light-shielding layer 32 less visible when viewed from the outside. In addition, the presence of the concealing layer 12 makes the light-shielding layer 32 even more difficult to see.

[0060] By making the spacing layer 20 a white synthetic resin layer, the ability to conceal the light-shielding layer 32 is improved. Furthermore, when combined with the white base concealing layer 122, the white background becomes more prominent, allowing the design of the pattern or other display layer 121 to stand out. Note that depending on the design, the spacing layer 20 may be a color other than white.

[0061] Even if the separation layer 20 is an uncolored synthetic resin layer (the color inherent to the resin), the black color of the light-shielding layer 32 becomes less noticeable due to the transmission and scattering of light rays inside the separation layer 20 or due to reflection on the front and back surfaces of the separation layer 20. Here, the uncolored synthetic resin layer may be colorless and transparent or hazy. By using an uncolored synthetic resin layer, the effort and cost of coloring the synthetic resin layer can be reduced. In particular, when the separation layer 20 is formed by extrusion coating, the effort of purging to remove the color when changing to another product type is reduced.

[0062] In this embodiment, the advantages of providing printing in two locations, on the inside of the outer film layer 11 and on the outside of the paper base layer 31, will be described.

[0063] Here, consider the case where a printed layer (hereinafter referred to as a light-shielding printed layer, and as an example, black printing) serving as a light-shielding layer is provided on the inside of the outer film layer 11. In this case, only the outer laminated portion 30 has the functions of the pattern or other display layer 121, the base concealing layer 122, and the light-shielding printed layer. In this case, on the inside of the outer film layer 11, from the outside to the inside, there are, in order, the pattern or other display layer 121, the base concealing layer 122, and the light-shielding printed layer. That is, in this embodiment, the light-shielding layer 32 is provided in the inner laminated portion 30, but in the above case, the light-shielding layer (light-shielding printed layer) is provided in the outer laminated portion 30.

[0064] The light-shielding printed layer is printed in black, and the base concealing layer 122 is printed in white to conceal the light-shielding printed layer. Furthermore, a single white print on the base concealing layer 122 does not have a sufficient ability to conceal the light-shielding printed layer, and may appear gray when viewed from the outside. To further increase the whiteness of the appearance, the number of times (the number of layers) the white print is applied to the base concealing layer 122 must be increased.

[0065] As described above, the number of prints (number of colors) is taken up by the light-shielding printed layer and the basic concealing layer 122, which is printed two or more times, so the number of prints (number of colors) remaining in the printing press is limited. As a result, the number of colors that can be used for pattern printing is reduced, which can result in a decrease in the vividness of the pattern. Therefore, by printing the light-blocking printed layer not on the outer film layer 11 but on another location, i.e., in this case on the paper base layer 31, the light-blocking printed layer is not printed on the shielding layer 12 of the outer film layer 11. This ensures that the number of printing colors available for the picture display layer 121 can be secured, resulting in vivid picture printing.

[0066] The laminated sheet 1 for a container may be prepared by separately preparing the outer laminated portion 10 and the inner laminated portion 30, and then bonding the outer laminated portion 10 and the inner laminated portion 30 via the separation layer 20.

[0067] Each layer of the outer laminated portion 10, which is based on the outer film layer 11 that does not contain a paper substrate, is subjected to coating, lamination, printing, etc. For this processing, the outer laminated portion 10 may be produced by known means used in the processing of flexible packaging, such as coating, lamination, printing, and post-processing (slitter, winding).

[0068] Each layer of the inner laminated portion 30, which has the paper base layer 31 as the base material, is subjected to coating, lamination, printing, etc. For this processing, the inner laminated portion 30 may be produced by known methods used in the processing of paper packaging, such as coating, lamination, printing, and post-processing (slitter, winding). Note that the weight ratio of paper in the container does not matter for the paper packaging here.

[0069] The outer laminated portion 10 and the inner laminated portion 30 are bonded via a separation layer 20. The bonding method may be extrusion lamination (sandwich lamination). Extrusion lamination ensures an appropriate thickness for the separation layer 20 and simultaneously bonds the layers, reducing the number of steps, shortening processing time, and reducing costs. Furthermore, because the outer bonding surface of the inner laminated portion 30 is a paper substrate, dry lamination, which involves applying an adhesive, may not be suitable. Other joining methods include thermal lamination via a pre-formed synthetic resin film.

[0070] In order to improve the bonding strength, the surfaces of the bonding layers may be subjected to anchor coating, corona treatment, flame treatment, etc., as needed. Alternatively, the molten thermoplastic resin used in extrusion lamination may be subjected to ozone treatment, etc.

[0071] The total light transmittance of the laminated sheet 1 for containers of this embodiment, including the light-shielding layer 32, may be 2% or less. When the total light transmittance is 2% or less, the contents can be protected from light incident from the outside. The total light transmittance is measured based on JIS-K7361-1 (1997). The measuring instrument may be a haze meter HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd.

[0072] The ISO whiteness of the laminate sheet 1 for containers of this embodiment, including the concealing layer 12, when viewed from the outside may be 70% or more. If the ISO whiteness is 70%, the sheet has sufficient whiteness in appearance, and even if a colorful pattern print or the like is provided on the white surface, the color remains sufficiently vivid. If the ISO whiteness is less than 70%, the pattern print may be affected depending on the design, resulting in a lack of clarity. The ISO whiteness index is measured based on JIS-P8148 (2018). The measuring instrument may be a spectrophotometer CMS-35SP manufactured by Murakami Color Research Laboratory Co., Ltd.

[0073] Next, various containers 50 are produced from the container laminate sheet 1. The containers herein are used for packaging, protecting, storing, transporting, displaying, etc. The container laminate sheet 1 of the present disclosure has a beautiful appearance and is therefore suitable as a container for consumers.

[0074] In recent years, from an environmental perspective, paper containers 51 with a base layer of a paper base layer 31 are preferred. The paper container 51 of the present disclosure has a decorative effect due to printing on the inside of the outer film layer 11, and further has a light-blocking property due to black printing on the outer surface of the paper base layer 31 as a light-blocking layer 32. In addition, when the weight ratio of paper in container 50 is 50% or more, container 50 is a paper container 51. Even if the base layer is paper base layer 31, if the weight ratio of paper is less than 50%, it is not a paper container 51.

[0075] As one aspect of the paper container 51 of this embodiment, a paper cup 52 shown in FIG. 4A is preferably used. For example, metal cans, plastic bottles, and the like are used as containers for liquids, but paper cups 52 are often used from the viewpoint of reducing volume after use and reducing the use of fossil resources. The paper cup 52 is used by filling it with contents, sealing the top opening with a lid, and then distributing it. It may then be placed in a store. During this process, light may be incident from the outside, but the paper cup 52 of this embodiment can block the light, thereby preventing deterioration of the interior. Although not described in detail here, the lid material used may also be provided with aesthetic appeal and light-blocking properties, and the laminate sheet 1 for containers of the present disclosure may be used.

[0076] Furthermore, similar to the paper cup 52, due to the advantages of the paper container 51, a gable-top paper container for liquids 53 as shown in Fig. 4B is preferably used as another aspect of the paper container 51 of this embodiment. The laminated sheet 1 for containers of this embodiment is used for the paper container body 531 of the gable-top paper container for liquids 53, and may be provided with a spout 532 for pouring the contents.

[0077] As yet another embodiment of the paper container 51 of this embodiment, a rectangular parallelepiped (brick-shaped) paper container 54 for liquids as shown in Fig. 4C is preferably used. The laminated sheet 1 for containers of this embodiment is used for the paper container body 541 of the rectangular parallelepiped (brick-shaped) paper container 54 for liquids, which may be equipped with a pull tab 542 that closes the spout hole for pouring the contents. Unlike the paper cup 52, the gable-top paper container 53 for liquids and the rectangular parallelepiped (brick-shaped) paper container 54 for liquids do not require a lid to seal the contents.

[0078] The above-mentioned paper cup 52, gable-top liquid paper container 53, and rectangular (brick-shaped) liquid paper container 54 are examples of the shape of the paper container 51, and other shapes such as a cylinder, a regular tetrahedron, or a tray shape may also be used. The paper cup 52, the gable-top paper container for liquids 53, and the rectangular parallelepiped (brick-shaped) paper container for liquids 54 are manufactured by known methods.

[0079] <Second aspect of the first embodiment> The concealing layer 12 will be described with reference to Fig. 2B, which is an enlarged view of part A in Fig. 1. Fig. 2B shows a laminated sheet 1 for a container according to a second aspect of this embodiment. The concealing layer 12 is made of a basic concealing layer 122, and unlike the first aspect of this embodiment, does not include a display layer 121 such as a pattern. In order to make the light-shielding layer 32 located inside the basic concealing layer 122 invisible from the outside, the basic concealing layer 122 may be printed in a single color (solid printing) over substantially the entire surface.

[0080] Second Embodiment A cross-sectional view of a laminate sheet 1 for a container of this embodiment is shown in FIG. 3A. The configuration of the outer laminated portion 10 differs from that of the first embodiment. The outer laminated portion 10 of this embodiment is composed of an outer film layer 11 on the outside, with a concealing layer 12 on the inside, and does not have an outer synthetic resin layer 13. The outer film layer 11 is not a relatively soft thermal adhesive resin (thermoplastic resin), but a film that is relatively hard and has high tensile strength, making it suitable for printing such as gravure printing. Examples of such films include PET film, nylon film, and polypropylene film. The above films may be uniaxially or biaxially stretched.

[0081] Since there is no hazy (thin, see-through, milky white) outer synthetic resin layer 13, the display layer 121 such as a pattern on the inner surface of the outer film layer 11 can be clearly seen, resulting in excellent aesthetic appeal. Since the outside of the container laminate sheet 1 of this embodiment does not have thermal adhesive properties, it is desirable to use an adhesive or the like when joining the outer surface of the outer film layer 11 to other parts. Alternatively, when forming a container, it is preferable to leave the outer surfaces of the container laminate sheet 1 unjoined and configure the thermally adhesive inner synthetic resin layers 33 to face each other. For example, there is skive hemming, which is a process in which the end is folded back so that the inner synthetic resin layer 33 faces the outer surface.

[0082] <Third embodiment> When the container laminate sheet 1 is to have barrier properties against oxygen, water vapor, fragrances, etc., a barrier layer 35 may be provided in the inner laminate part 30, as shown in Fig. 3B. The inner laminate part 30 is composed of, at least from the outside in order, a light-shielding layer 32, a paper base layer 31, an intermediate adhesive layer 34, a barrier layer 35, and an inner synthetic resin layer 33. The barrier layer 35 is appropriately selected depending on the substance to be barriered, and may be various vapor-deposited films such as silica-deposited PET film, or a resin layer having barrier properties such as EVOH or MXD6 nylon. However, in the present disclosure, metal foils such as aluminum foils are not desirable because compatibility with metal detectors is required. [Example]

[0083] The embodiments of the present disclosure will be described in more detail below with reference to examples.

[0084] Example 1 A cross-sectional view of a laminate sheet 1 for a container of Example 1 is shown in Figure 1, and an enlarged view of part A in Figure 1 is shown in Figure 2A. This example corresponds to the first aspect of the above-mentioned first embodiment.

[0085] The laminated sheet 1 for a container of Example 1 had the following configuration. The left side of Fig. 1 is the outside and the right side is the inside. Note that " / " indicates the boundary between adjacent layers. (outside) Outer synthetic resin layer 13 (LDPE 20μm Japan Polyethylene Co., Ltd. LC520) / Outer film layer 11 (PET film 12 μm Toyobo Co., Ltd. T4102) / Display layer 121 (gravure printing, 6-color pattern printing) / Basic concealing layer 122 (gravure printing, white monochromatic printing, double layer printing) / Separation layer 20 (LDPE 30 μm Japan Polyethylene Co., Ltd. LC520) / Light-shielding layer 32 (gravure printing, black monochrome printing) Paper base layer 31 (cup base paper 270 g / m 2 O&C Ivory Board Co., Ltd. CH Acid-Resistant Coating WCOC) / Inner synthetic resin layer 33 (LDPE 25μm Japan Polyethylene Co., Ltd. LC520) (Inside)

[0086] A method for producing the laminated sheet 1 for containers will be described.

[0087] First, the outer laminated portion 10 was produced. A roll of film to become the outer film layer 11 was fed to a gravure printing machine with an eight-color (eight times) printing function. A display layer 121 such as a pattern was gravure printed on the inner surface of the outer film layer 11. Six colors were used for the pattern printing in this example. Next, white gravure printing was applied twice to the inside of the pattern display layer 121 as a base concealing layer 122. Since an eight-color gravure printing machine was used in this example, the pattern display layer 121 and the base concealing layer 122 were printed in a single process.

[0088] If a light-shielding layer 32 is further printed inside the basic concealing layer 122 of the outer film layer 11, the gravure printing will require nine colors (nine times), which means that the gravure printing process will require at least two steps (two passes), resulting in increased costs and working time. After the gravure printing was completed, the film that would become the outer film layer 11 was rewound into a roll and stored.

[0089] Next, the roll of printed film that would become the outer film layer 11 was unwound and fed to an extrusion coating machine. Molten LDPE was extruded onto the outside of the film to form an outer synthetic resin layer 13 with a thickness of 20 μm.

[0090] Next, the inner laminated portion 30 was produced. The outer laminated portion 10 and the inner laminated portion 30 are produced in separate steps, so the order of production does not matter.

[0091] The paper base material that would become the paper base material layer 31 was supplied to a gravure printing machine, and single-color black gravure printing was performed in one color (once) on the outside of the paper base material layer 31 to form the light-shielding layer 32. Note that to further improve the light-shielding properties, gravure printing may be performed two or more times, but in this example, sufficient light-shielding properties were obtained with one printing, so gravure printing was performed once. After the gravure printing was completed, the paper substrate layer 31 was wound up again into a roll and stored.

[0092] Next, the roll of printed paper base layer 31 was unwound and fed to an extrusion coating machine, and a 25 μm layer of LDPE was formed on the inner side (the side opposite to the printed surface) of the printed paper base layer 31 by extrusion coating. After extrusion coating was completed, the inner laminate 30 was rewound into a roll and stored.

[0093] The outer laminate 10 and the inner laminate 30 prepared by the above procedure were fed into an extrusion laminator and bonded. LDPE was used as the molten resin to bond the two laminates, and the LDPE layer became the separation layer 20. The LDPE used for the separation layer 20 in this example was uncolored, and the color was inherent to the resin, so it was not colorless and transparent, but it could be seen through.

[0094] The processing procedure was as follows: molten LDPE was extruded in a film form onto the inside of the outer laminated section 10 being conveyed by an extrusion laminator. The inner laminated section 30 was fed into or near the position where the outer laminated section 10 and the LDPE came into contact. At this point, the LDPE came into contact with the outside of the inner laminated section 30. Thereafter, when the three-layered outer laminate portion 10, the separation layer 20, and the inner laminate portion 30 are cooled, the molten separation layer 20 solidifies, and the three layers are bonded together. In this manner, the laminate sheet 1 for a container of this embodiment is completed.

[0095] <Example 2> Example 2 differs from Example 1 in the layer configuration of the concealing layer 12. A cross-sectional view of the laminated sheet 1 for a container of this example is shown in Figure 1, and an enlarged view of part A in Figure 1 is shown in Figure 2B. This example corresponds to the second aspect of the first embodiment described above. The concealing layer 12 of this embodiment does not have the pattern or other display layer 121 that was provided in Example 1, and only has a basic concealing layer 122. The basic concealing layer 122 of this embodiment is gravure printed twice in white (solid printing) over almost the entire surface.

[0096] The laminated sheet 1 for a container of Example 2 had the following configuration: The left side of Fig. 1 is the outside, and the right side is the inside. (outside) Outer synthetic resin layer 13 (LDPE 20μm Japan Polyethylene Co., Ltd. LC520) / Outer film layer 11 (PET film 12 μm Toyobo Co., Ltd. T4102) / Basic concealing layer 122 (gravure printing, white monochromatic printing, double layer printing) / Separation layer 20 (LDPE 30 μm Japan Polyethylene Co., Ltd. LC520) / Light-shielding layer 32 (gravure printing, black monochrome printing) Paper base layer 31 (cup base paper 270g / m2 O&C Ivory Board Co., Ltd. CH Acid-Resistant Coating WCOC) / Inner synthetic resin layer 33 (LDPE 25μm Japan Polyethylene Co., Ltd. LC520) / (Inside)

[0097] The other layer configurations and manufacturing methods are the same as those in the first embodiment.

[0098] Example 3 Example 3 differs from Example 1 in the layer structure of the outer laminated portion 10. A cross-sectional view of the laminated sheet 1 for a container of this example is shown in Figure 3A. This example corresponds to the second embodiment described above. The outer laminated portion 10 of this embodiment does not have the outer synthetic resin layer 13 that was provided in Example 1, and instead consists of an outer film layer 11 and a concealing layer 12. The concealing layer 12 includes a display layer 121 such as a pattern and a basic concealing layer 122, as in Example 1.

[0099] The laminated sheet 1 for a container of Example 3 had the following configuration: The left side of Fig. 3A is the outside, and the right side is the inside. (outside) Outer film layer 11 (PET film 12 μm Toyobo Co., Ltd. T4102) / Display layer 121 (gravure printing, 6-color pattern printing) / Basic concealing layer 122 (gravure printing, white monochromatic printing, double layer printing) / Separation layer 20 (LDPE 30 μm Japan Polyethylene Co., Ltd. LC520) / Light-shielding layer 32 (gravure printing, black monochrome printing) Paper base layer 31 (cup base paper 270 g / m 2 O&C Ivory Board Co., Ltd. CH Acid-Resistant Coating WCOC) / Inner synthetic resin layer 33 (LDPE 25μm Japan Polyethylene Co., Ltd. LC520) / (Inside)

[0100] The other layer configurations and manufacturing methods are the same as those in the first embodiment.

[0101] Example 4 Example 4 differs from Example 1 in the layer structure of the inner laminate portion 30. A cross-sectional view of the laminate sheet 1 for a container of this example is shown in Figure 3B. This example corresponds to the above-mentioned third embodiment. The inner laminated portion 30 of this example was different from Example 1 in that it had an additional barrier layer 35 and intermediate adhesive layer 34. The required barrier property in this example was oxygen barrier property. The barrier layer 35 was a silica-deposited PET film.

[0102] The laminated sheet 1 for a container of Example 4 had the following configuration: The left side of Fig. 3B is the outside, and the right side is the inside. (outside) Outer synthetic resin layer 13 (LDPE 20μm Japan Polyethylene Co., Ltd. LC520) / Outer film layer 11 (PET film 12 μm Toyobo Co., Ltd. T4102) / Display layer 121 (gravure printing, 6-color pattern printing) / Basic concealing layer 122 (gravure printing, white monochromatic printing, double layer printing) / Separation layer 20 (LDPE 30 μm Japan Polyethylene Co., Ltd. LC520) / Light-shielding layer 32 (gravure printing, black monochrome printing) Paper base layer 31 (cup base paper 270 g / m 2 O&C Ivory Board Co., Ltd. CH Acid-Resistant Coating WCOC) / Intermediate adhesive layer 34 (ethylene methacrylic acid copolymer resin (EMAA) 20 μm Mitsui Dow Polychemical N0908N) / Barrier layer 35 (silica vapor-deposited PET film 12 μm Dai Nippon Printing IB-PET-UBP) / Inner synthetic resin layer 33 (LDPE 25μm Japan Polyethylene Co., Ltd. LC520) / (Inside)

[0103] The outer laminate portion 10 and the separation layer 20 are the same as those in Example 1, but the inner laminate portion 30 is different from those in Example 1. Therefore, a method for producing the inner laminate portion 30 will be described here. The paper base material that would become the paper base layer 31 was supplied to a gravure printing machine, and black monochrome gravure printing was performed in one color (once) on the outer side of the paper base layer 31 to form a light-shielding layer 32. After the gravure printing was completed, the paper base layer 31 was wound up again into a roll and stored.

[0104] In the next step, the roll of printed paper substrate layer 31 was unwound and fed to an extrusion laminator, where a barrier layer 35 (silica-deposited PET 12 μm) was laminated on the inside of the paper substrate layer 31 by extrusion lamination (sandwich lamination) with a molten intermediate adhesive layer 34 (EMAA 20 μm) interposed therebetween.

[0105] Next, an inner synthetic resin layer 33 (LDPE 25 μm) was formed on the inner side of the barrier layer 35 by extrusion lamination.

[0106] In order to improve the bonding strength, the surfaces of the bonding layers may be subjected to anchor coating, corona treatment, flame treatment, etc., as needed. Alternatively, the molten resin may be subjected to ozone treatment, etc.

[0107] The other layer configurations and manufacturing methods are the same as those in the first embodiment.

[0108] <Comparative Example> A cross-sectional view of a comparative example of laminated sheet 6 for containers is shown in Fig. 5. The reference numerals of the elements of the comparative example of laminated sheet 6 for containers are in the 60s, 70s, and 80s.

[0109] The layer structure of the comparative laminated sheet 6 for containers will be described. The container laminate sheet 6 had an outer laminate portion 60, a separation layer 70, and an inner laminate portion 80 in this order from the front side (the left side in FIG. 5).

[0110] The outer laminated portion 60 will now be described. In the comparative example, the outer laminated portion 60 is composed of, from the outside, an outer synthetic resin layer 63, an outer film layer 61, a concealing layer 62, and an outer light-shielding layer 64. The concealing layer 62 is composed of a basic concealing layer 622, and is printed in white (solid printing) over almost the entire surface. The outer light-shielding layer 64 is printed in black (solid printing) over almost the entire surface.

[0111] The inner laminated portion 80 is composed of, from the outside in order, a paper base layer 81 and an inner synthetic resin layer 83, and does not include a light-shielding layer. In the comparative example, a light-shielding layer that blocks external light is provided in the outer laminated portion 60 as an outer light-shielding layer 64, and is not provided in the inner laminated portion 80, unlike the present disclosure.

[0112] The comparative laminate sheet 6 for a container had the following structure: The left side of Fig. 5 is the outside and the right side is the inside. (outside) Outer synthetic resin layer 63 (LDPE 20μm Japan Polyethylene Co., Ltd. LC520) / Outer film layer 61 (PET film 12 μm Toyobo Co., Ltd. T4102) / Basic concealing layer 622 (gravure printing, white monochromatic printing, double layer printing) / Outer light-shielding layer 64 (gravure printing, black monochrome printing) Separation layer 70 (LDPE 30 μm Japan Polyethylene Co., Ltd. LC520) / Paper base layer 81 (cup base paper 270 g / m 2 O&C Ivory Board Co., Ltd. CH Acid-Resistant Coating WCOC) / Inner synthetic resin layer 83 (LDPE 25μm Japan Polyethylene Co., Ltd. LC520) / (Inside)

[0113] <Evaluation> The total light transmittance and ISO whiteness index were measured for the produced laminate sheet for containers 1 of Example 2 and the laminate sheet for containers 6 of Comparative Example. Each value was an average value obtained by measuring the sample five times. The total light transmittance was measured in accordance with JIS-K7361-1 (1997) using a haze meter HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd. The ISO whiteness index was measured based on JIS-P8148 (2018) using a spectrophotometer CMS-35SP manufactured by Murakami Color Research Laboratory Co., Ltd. The measurement results are shown in Table 1.

[0114] [Table 1]

[0115] The total light transmittance of Example 2 was 1.96%, which indicates sufficient light blocking properties, and the ISO whiteness was 75.6%, which indicates sufficient whiteness. The comparative example had a total light transmittance of 1.94%, which means it had sufficient light blocking properties, but the ISO whiteness was 60.4%, which was not sufficient. Both Example 2 and the Comparative Example have a concealing layer printed in white and a light-blocking layer printed in black, but Example 2 is superior in terms of whiteness. Furthermore, although the separating layer 20 of Example 2 is formed of an uncolored synthetic resin, the laminated sheet 1 for containers has sufficient whiteness.

[0116] The laminated sheet 1 for containers in Example 1 has a printed pattern, but the ISO whiteness of the area where no pattern is present is the same as in Example 2. In other words, the high whiteness of the background color allows the pattern to be expressed vividly. In the container laminate sheet 1 of Example 4, the layer structure from the paper base layer 31 onwards is the same as in Example 1 or Example 2, and therefore the ISO whiteness is similar. The container laminate sheet 1 of Example 3 has a layer structure in which the outer synthetic resin layer 13 of Example 1 has been removed. In Example 2, the outer synthetic resin layer 13 is LDPE, which is hazy. Since the outer synthetic resin layer 13 is removed, the ISO whiteness of Example 3 is equal to or higher than that of Example 2.

[0117] The laminated sheet 1 for containers of the present disclosure has sufficient light-blocking properties despite not having aluminum foil (metal foil), and also has sufficient whiteness when viewed from the outside. [Explanation of symbols]

[0118] 1. Laminated sheet for containers 10 Outer laminate section 11 outer film layer 12 Hidden Layer 121 Picture display layer 122 Basic Hiding Layer 13 Outer synthetic resin layer 20 Spacing layer 30 Inner laminate 31 Paper base layer 32 Light blocking layer 33 Inner synthetic resin layer 34 Intermediate adhesive layer 35 Barrier Layer 50 containers 51 Paper containers 52 Paper Cups 53 Gable-top liquid cartons 531 Paper container body 532 spout 54 Rectangular (brick-shaped) liquid paper container 541 Paper container body 542 pull tab 6 Comparative Example Laminated Sheet for Containers 60 Outer laminate section 61 outer film layer 62 Hidden Layer 622 Basic Hiding Layer 63 Outer synthetic resin layer 64 Outer light shielding layer 70 Spacing layer 80 inner laminate 81 Paper base layer 83 Inner synthetic resin layer

Claims

1. The film is provided with, from the outside, at least an outer laminated portion including an outer film layer having a concealing layer, and an inner laminated portion including a separation layer and a paper substrate layer having a light-shielding layer, in that order; The outer laminated portion includes an outer film layer and a concealing layer in this order from the outside, the inner laminated portion includes, in order from the outside, a light-shielding layer, a paper base layer, and an inner synthetic resin layer; The concealing layer includes a base concealing layer at least on the spacing layer side, The separation layer is a synthetic resin layer. Laminated sheet for containers.

2. 2. The laminate sheet for containers according to claim 1, which has a total light transmittance of 2% or less.

3. 3. The laminated sheet for containers according to claim 1, wherein the outer surface has an ISO whiteness of 70% or more.

4. The laminated sheet for a container according to claim 1 , wherein the light-shielding layer is a printed layer.

5. The laminated sheet for containers according to claim 1 , wherein the light-shielding layer is provided on the outer side of the paper base layer.

6. The laminated sheet for a container according to any one of claims 1 to 5, wherein the outer film layer is see-through, and the concealing layer is provided inside the outer film layer.

7. The laminated sheet for a container according to any one of claims 1 to 6, wherein the base concealing layer is white.

8. The laminated sheet for a container according to claim 1 , wherein the basic concealing layer of the concealing layer is a printed layer.

9. The laminated sheet for a container according to claim 8 , wherein the basic concealing layer of the concealing layer is printed with a background pattern.

10. The laminated sheet for a container according to any one of claims 1 to 9, wherein the spacing layer is an adhesive layer.

11. The laminated sheet for a container according to any one of claims 1 to 10, wherein the spacing layer is an extrusion-laminated synthetic resin layer.

12. The laminated sheet for a container according to any one of claims 1 to 11, wherein the spacing layer is white.

13. The laminated sheet for a container according to any one of claims 1 to 11, wherein the spacing layer is see-through.

14. A container comprising at least the laminate sheet for a container according to any one of claims 1 to 13.

15. 15. The container of claim 14, wherein the container is a paper container.

16. 16. The container of claim 15, wherein the paper container is a paper cup.

17. 16. The container according to claim 15, wherein the carton is a gable-top liquid carton.

18. The container according to claim 15, wherein the paper container is a rectangular parallelepiped paper container for liquids.

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