Laminated container and method for manufacturing a laminated container

Abstract

We propose a laminated container 100 that can be disposed of as paper waste, and a method for manufacturing the laminated container 100. [Solution] The laminated container 100 according to the present disclosure comprises a container portion 22 having a body portion 20 for containing contents, a mouth portion 10 connected to the upper end of the body portion 20, and a bottom portion 40 that closes the lower end of the body portion 20, and a label portion 28 that covers at least a part of the body portion 20 from the outside, wherein the container portion 22 has a laminated structure in which a low-density polyethylene resin layer 22c, an intermediate layer 22b, and a high-density polyethylene resin layer 22a are laminated in that order from the outside, the intermediate layer 22b contains a paper-blended resin which is a polyolefin resin blended with a paper component, the layer of the label portion 28 that is attached to the container portion 22 has a thickness of 200 μm or more and 500 μm or less, a Beck smoothness of 10 to 800 seconds, and the proportion of the paper component in the whole of the laminated container 100 is 51% by weight or more.

Description

Technical Field

[0001] The present disclosure relates to a laminated container and a method for manufacturing the laminated container.

Background Art

[0002] Currently, due to social demands such as reducing the environmental load, it is required to reduce the amount of plastic used in plastic containers, and in particular, the development of composite containers using paper is required. For example, Patent Document 1 proposes a laminated container that makes it easy to discard the label portion as paper waste.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the laminated container described in Patent Document 1, a large amount of plastic is used in parts other than the label portion, and the entire container cannot be discarded as combustible waste like paper, so there is still room for improvement in this regard.

[0005] The present disclosure aims to solve such problems, and its object is to propose a laminated container and a method for manufacturing the laminated container that can discard the entire container as paper waste.

Means for Solving the Problems

[0006] The present disclosure has been made to solve the above problems, and the laminated container of the present disclosure is [1] a container part having a body part for accommodating contents, a mouth part connected to the upper end part of the body part, and a bottom part for closing the lower end part of the body part, A label portion that covers at least a part of the body from the outside and A stacked container equipped with, The container section has a laminated structure in which a low-density polyethylene resin layer, an intermediate layer, and a high-density polyethylene resin layer are stacked in that order from the outside. The aforementioned intermediate layer contains a paper-based resin, which is a polyolefin resin blended with paper components. The layer attached to the container portion in the label portion is made of paper with a thickness of 200 μm or more and 500 μm or less, and has a Beck smoothness of 10 seconds or more and 800 seconds or less. The aforementioned laminated container is characterized in that the proportion of paper components in the overall structure is 51% by weight or more.

[0007] Furthermore, the laminated container of this disclosure is [2] In the configuration described in [1] above, the intermediate layer is preferably a resin layer in which a low-density polyethylene resin is blended with the paper-based resin.

[0008] Furthermore, the laminated container of this disclosure is [3] In the configuration described in [1] or [2] above, it is preferable that the label portion covers 50% or more of the surface of the container portion.

[0009] Furthermore, the manufacturing method of the laminated container described herein is [4] A container having a body for containing contents, a mouth connected to the upper end of the body, and a bottom that closes the lower end of the body, A label portion that covers at least a part of the body from the outside and A method for manufacturing a stacked container, comprising: The label portion is placed inside the blow molding die, In the blow molding die, the container portion is blow-molded, and the label portion is laminated on the outside of the container portion as an in-mold label. Includes, The container section has a laminated structure in which a low-density polyethylene resin layer, an intermediate layer, and a high-density polyethylene resin layer are stacked in that order from the outside. The intermediate layer contains a paper-containing resin in which a paper component is blended with a polyolefin resin. The layer adhered to the container portion in the label portion is made of paper with a thickness of 200 μm or more and 500 μm or less, and a Bekk smoothness of 10 to 800 seconds. The proportion of the paper component in the entire laminated container is 51% by weight or more.

Advantages of the Invention

[0010] According to the present disclosure, it is possible to propose a laminated container that can be discarded as paper waste for the entire container, and a method for manufacturing the laminated container.

Brief Description of the Drawings

[0011] [Figure 1A] It is a front view of a laminated container according to an embodiment of the present disclosure. [Figure 1B] It is a left side view of a laminated container according to an embodiment of the present disclosure. [Figure 2] It is a bottom view of a laminated container according to an embodiment of the present disclosure. [Figure 3] It is a detailed view of part A in FIG. 1A. [Figure 4] It is a flowchart showing the implementation procedure of a method for manufacturing a laminated container according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0012] Hereinafter, the present disclosure will be described more specifically with reference to the drawings.

[0013] Figure 1A is a front view showing the configuration of a laminated container 100 according to an embodiment of the present disclosure. The laminated container 100 includes a cylindrical body portion 20 having an elliptical shape (see Figure 2) in a bottom view that forms an accommodation space S for the contents, a mouth portion 10 that is connected to the upper end portion of the body portion 20 via a shoulder portion 30 and forms an opening 10a inside for supplying and discharging the contents, and a bottom portion 40 that closes the lower end portion of the body portion 20. On the outer peripheral surface of the mouth portion 10, as shown in Figure 1A, a male screw portion 10b is provided that allows a cap, a pump, etc. to be attached by screw engagement. A container portion 22 shown in a partial cross-section in Figure 1A forms the entire region of the mouth portion 10, the shoulder portion 30, the body portion 20, and the bottom portion 40 in Figure 1A.

[0014] In this specification, the claims, and the drawings, the side where the mouth portion 10 is located is defined as the upper side (the upper side in Figure 1A), and the side where the bottom portion 40 is located is defined as the lower side (the lower side in Figure 1A). Also, in the description of the layer structure of the laminated container 100, the side of the accommodation space S is defined as the inner side, and the side of the label portion 28 of the laminated container 100 is defined as the outer side. Further, the radially outer side means the direction away from the central axis O along a straight line passing through the central axis O of the laminated container 100 in Figure 1A and perpendicular to the central axis O, and the radially inner side means the direction toward the central axis O along the straight line. The circumferential direction is the rotational direction around the central axis.

[0015] As shown in Figure 1A and Figure 3, the body portion 20 includes a container portion 22 that forms the accommodation space S for the contents, and a label portion 28 that covers the container portion 22 from the radially outer side and is laminated on the container portion 22.

[0016] The container portion 22 that forms the skeleton of the laminated container 100 is laminated in order from the outside with a low-density polyethylene resin layer 22c, an intermediate layer 22b, and a high-density polyethylene resin layer 22a. The container portion 22 only needs to have the resin layers arranged in the above order from the outside. For example, other layers may be arranged between the low-density polyethylene resin layer 22c and the intermediate layer 22b, between the intermediate layer 22b and the high-density polyethylene resin layer 22a, inside the high-density polyethylene resin layer 22a, etc.

[0017] In this embodiment, the low-density polyethylene resin layer 22c is a resin layer that comes into contact with the outer label portion 28, and can be formed as a resin layer containing low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE). In this embodiment, the low-density polyethylene resin layer 22c has a thickness of 45 μm to 50 μm. By using a soft low-density polyethylene resin layer 22c as the outermost layer of the container portion 22 that comes into contact with the label portion 28, the low-density polyethylene resin layer 22c can easily penetrate into the inner surface of the paper layers constituting the label portion 28, thereby improving the adhesion between the container portion 22 and the label portion 28.

[0018] In this embodiment, the intermediate layer 22b is a resin layer obtained by blending a paper-based resin, which is a polyolefin resin blended with a paper component, with a low-density polyethylene resin. In this embodiment, the intermediate layer 22b has a thickness of 261 μm to 288 μm. The intermediate layer 22b may be a resin layer in which other resins are blended in addition to the paper-based resin and the low-density polyethylene resin, or it may be a resin layer in which resins other than the low-density polyethylene resin (for example, other polyolefin resins or polyester resins) are blended with the paper-based resin. The paper-based resin may be, for example, polypropylene (PP) blended with a paper component. The paper-based resin may also be, for example, polyethylene (PE) blended with a paper component, other than polypropylene (PP).

[0019] The proportion of the paper-based resin in the intermediate layer 22b can be, for example, about 80%. In that case, the proportion of low-density polyethylene resin other than the paper-based resin in the intermediate layer 22b is about 20%. The proportion of paper components in the paper-based resin can be about 51%. That is, the proportion of polypropylene (PP) other than the paper components in the paper-based resin is about 49%. Therefore, the proportion of paper components in the intermediate layer 22b can be 80% × 51% = about 41%. It is preferable that the proportion of the paper-based resin in the intermediate layer 22b be 60% or more. It is also preferable that the proportion of paper components in the paper-based resin be 50% or more.

[0020] In this way, by providing an intermediate layer 22b containing paper components in the container portion 22 that forms the framework of the laminated container 100, the proportion of paper components in the laminated container 100 can be increased (51% by weight or more), making it possible to dispose of the entire laminated container 100 as paper waste.

[0021] In this embodiment, the high-density polyethylene resin layer 22a can be formed as a resin layer containing high-density polyethylene (HDPE). In this embodiment, the high-density polyethylene resin layer 22a has a thickness of 85 μm to 93 μm. By using a high-density polyethylene resin layer 22a containing highly rigid high-density polyethylene as the inner layer of the container portion 22, the container portion 22 can be given a predetermined strength, and its water permeability resistance can be improved. It is preferable that the thickness of the high-density polyethylene resin layer 22a is at least 50 μm.

[0022] As described above, the high-density polyethylene resin layer 22a is provided for purposes such as providing strength to the container portion 22, so it does not necessarily have to be the innermost layer as shown in Figure 3, and a further resin layer may be provided inside the high-density polyethylene resin layer 22a.

[0023] In this embodiment, the label portion 28 is a paper in-mold label (IML) having a thickness of 200 μm to 500 μm. Note that "paper" does not necessarily mean that it is composed solely of paper, as will be described later. The label portion 28 is not coated with adhesive, and adhesion between the container portion 22 and the label portion 28 is ensured by the low-density polyethylene resin layer 22c, which is the outermost layer of the container portion 22, penetrating the inner surface of the paper layer constituting the label portion 28. The label portion 28 has a smoothness within the range of Beck smoothness: 10 seconds to 800 seconds as specified in JIS P8119:1998. The label portion 28 having a smoothness within this range and having an appropriate surface roughness provides excellent transportability of the label to the mold, and the low-density polyethylene resin layer 22c, which is the outermost layer of the container portion 22, penetrating the irregularities on the inner surface of the label portion 28, thereby ensuring adhesion between the low-density polyethylene resin layer 22c and the label portion 28.

[0024] By making the thickness of the label portion 28 200 μm or more, the proportion of paper components in the entire laminated container 100 can be increased.

[0025] Furthermore, by making the thickness of the label portion 28 500 μm or less, the bending rigidity can be kept low, so the squeezeability of the bottle is not impaired after the label is applied. In addition, the occurrence of bottle deformation (sink marks) can be prevented, and the reduction in drop impact resistance can be suppressed.

[0026] The label portion 28 has a substantially rectangular shape, as shown in Figures 1A and 1B, and extends circumferentially to the vicinity of the parting line PL (see Figure 1B) which extends vertically. In this embodiment, the distance from the parting line PL to the circumferential end of the label portion 28 is about 2 mm to 3 mm. The parting line PL is a line formed on the mating surface of the mold for blow molding the laminated container 100, and in the example shown in Figures 1B and 2, it is formed at two locations in the circumferential direction on the mouth portion 10 and the body portion 20 of the laminated container 100, as well as on the bottom portion 40. In the bottom view of Figure 2, the parting line PL extends in the left-right direction. In this embodiment, the label portion 28 has an area of ​​about 70% of the surface area of ​​the laminated container 100. Preferably, the label portion 28 has an area of ​​at least 50% of the surface area of ​​the laminated container 100. By attaching a large-area label portion 28 to the container portion 22 in this way, the proportion of paper components in the laminated container 100 can be increased, making it easier to dispose of the entire laminated container 100 as paper waste. In this embodiment, a label portion 28 of the same size is also attached to the body portion 20 on the far side in the vertical direction of the paper in Figure 1A.

[0027] It is preferable that the average thickness of the intermediate layer 22b in the area to which the label portion 28 of the body portion 20 is attached is 60% or more of the average thickness of the body portion 20 in that area. This allows for an increase in the proportion of paper components.

[0028] In this embodiment, the specific gravity of the label portion 28 is 0.5 to 0.7 g / cm³. 3It is preferable that the specific gravity of the label portion 28 is 0.5 g / cm³. 3 If the specific gravity is less than 0.7 g / cm³, the label portion 28 is prone to breaking due to its low rigidity, resulting in poor transportability of the label portion 28 during the molding of the laminated container 100. On the other hand, if the specific gravity of the label portion 28 is 0.7 g / cm³, 3 If the pressure exceeds this limit, the rigidity of the label portion 28 becomes high, resulting in poor drop impact resistance of the container after application, reduced squeezeability of the body portion 20, and a higher likelihood of defects such as deformation of the container (sink marks).

[0029] The label portion 28 may have a structure in which a resin film is laminated on the outside of the paper layer. By providing a resin film on the outside of the paper layer of the label portion 28, the water resistance of the label portion 28 can be improved, and the glossiness can also be improved, thereby enhancing its design appeal.

[0030] The low-density polyethylene resin layer 22c, the intermediate layer 22b, and the high-density polyethylene resin layer 22a of the container section 22 may be made of virgin polyolefin resin, or a resin mixed with recycled material. Furthermore, layers of virgin material and layers containing recycled material can be laminated. The resin contained in the container section 22 may consist solely of recycled material, or plant-derived resin may be used.

[0031] In this embodiment, the label portion 28 is a paper in-mold label that can be attached to the outer surface of the container portion 22 during in-mold molding. The label portion 28 contains 70% to 100% by weight of paper components, which are combustible waste. Thus, in this embodiment, by having the label portion 28 contain a large amount (70% by weight or more) of paper components, which are combustible waste components, the proportion of combustible waste components in the laminated container 100 is increased to 51% by weight or more.

[0032] In this embodiment, the label portion 28 is a label member formed as an in-mold label when the container portion 22 is extruded and blow-molded, and the paper layer of the label portion 28 contains 70% to 100% by weight of paper components which are combustible waste. In this embodiment, as will be described later, the label portion 28 is placed in advance in the blow molding die used to extrude and blow-molde the container portion 22, and is laminated onto the outer surface of the container portion 22 by extrude and blow molding. A further adhesive layer may be provided on the inner surface of the label portion 28.

[0033] In this embodiment, by increasing the proportion of paper components in the stacked container 100 to 51% by weight or more, the entire stacked container 100 can be disposed of as paper. With this configuration, the stacked container 100 can be processed after use without generating non-combustible waste.

[0034] In this embodiment, the outer surface of the label portion 28 may be decorated by means of, for example, printing, transfer, vapor deposition, painting, or adding a coloring agent.

[0035] The stacked container 100 of this embodiment has a substantially elliptical shape in plan view and bottom view (see Figure 2). The bottom portion 40 is curved inward towards the center of the container in the radial direction (see the dashed line portion of the bottom portion 40 in Figure 1A), and the stacked container 100 can stand on its own by resting the peripheral edge of the bottom portion 40 on the ground. A pinch-off portion 40a is formed on the bottom portion 40 by cutting with a split die during blow molding. A parting line PL is formed on the bottom portion 40, extending in the left-right direction in the figure.

[0036] Furthermore, it is preferable that the approximately elliptical shape of the laminated container 100 when viewed from the bottom is such that the minor axis (vertical length in Figure 2) is 0.3 times or more the major axis (horizontal length in Figure 2). With this configuration, even if the intermediate layer 22b of the laminated container 100 is configured to contain paper-reinforced resin, the difference in the blow ratio (the ratio of the diameter of the container body after blowing to the diameter of the cylindrical parison before blowing) depending on the circumferential position during blow molding is reduced, thus enabling good moldability.

[0037] Furthermore, in this embodiment, as shown in Figure 1A, rounded surfaces 30a and 40b with a radius of 5 mm or more are provided on the peripheral edges of the shoulder portion 30 and bottom portion 40 of the laminated container 100. This configuration makes it difficult for stress concentration to occur on the shoulder portion 30 and bottom portion 40 during stretch blow molding, thus enabling good shaping properties and drop impact resistance. It is preferable that the content volume be 1100 mL or less, taking into consideration the drop impact resistance of the laminated container 100.

[0038] The laminated container 100 having the configuration shown in Figures 1A to 3 can be manufactured, for example, by extrusion blow molding. When manufacturing the laminated container 100, first, the label portion 28 is placed near the wall surface inside the blow molding die (step S101 in Figure 4). The label portion 28 placed inside the blow molding die is fixed inside the blow molding die by means of vacuum suction or the like.

[0039] Next, a laminated parison, consisting of a low-density polyethylene resin layer 22c, an intermediate layer 22b, and a high-density polyethylene resin layer 22a that constitute the container portion 22, is supplied into the blow molding die, and the container portion 22 is extruded and blow molded, while the label portion 28 is laminated to the outside of the container portion 22 as an in-mold label (step S103 in Figure 4). Adhesive may be applied to the inner surface of the label portion 28, and convex ribs or the like may be formed in the area where the label end on the container portion 22 is fixed to increase the attachment strength by interlocking with the surface of the container portion 22.

[0040] Once the extrusion blow molding is complete, the vacuum suction of the label section 28 is stopped, the mold is opened, and the stacked container 100 is removed, thus ending the manufacturing process.

[0041] In this embodiment, it is preferable that the maximum blow ratio in extrusion blow molding (the ratio of the diameter of the container body (maximum diameter) after blow molding to the diameter of the cylindrical parison before blow molding) be 2 or less. With this configuration, the maximum blow ratio during blow molding can be suppressed, and good moldability can be obtained.

[0042] The laminated structure of the container portion 22 may be formed not only by extrusion blow molding, but also by stretch blow molding a laminated preform in which the container portion 22 is laminated, and by in-mold molding the label portion 28.

[0043] As described above, the laminated container 100 according to this embodiment comprises a container portion 22 having a body portion 20 for containing contents, a mouth portion 10 connected to the upper end of the body portion 20, and a bottom portion 40 that closes the lower end of the body portion 20, and a label portion 28 that covers at least a part of the body portion 20 from the outside. The container portion 22 has a laminated structure in which a low-density polyethylene resin layer 22c, an intermediate layer 22b, and a high-density polyethylene resin layer 22a are laminated in that order from the outside. The intermediate layer 22b contains a paper-blended resin which is a polyolefin resin blended with a paper component. The layer of the label portion 28 that is attached to the container portion 22 is made of paper with a thickness of 200 μm to 500 μm, has a Beck smoothness of 10 to 800 seconds, and is configured such that the proportion of paper components in the whole of the laminated container 100 is 51% by weight or more. By adopting this configuration, the label portion 28 is made of paper, and paper components are also included in the container portion 22 that forms the framework of the laminated container 100, thereby increasing the proportion of paper components in the entire laminated container 100 to 51% by weight or more. Therefore, the entire laminated container 100 can be disposed of as paper waste.

[0044] Furthermore, in this embodiment, the intermediate layer 22b is configured as a resin layer in which low-density polyethylene resin is blended with paper-based resin. By adopting this configuration, a low-density polyethylene resin with excellent moldability is blended into the intermediate layer 22b containing paper components on the container portion 22 side, thereby increasing the proportion of paper components on the container portion 22 side and improving the moldability of the container portion 22.

[0045] Furthermore, in this embodiment, the label portion 28 is configured to cover 50% or more of the surface of the container portion 22. By adopting this configuration, the proportion of paper components in the entire laminated container 100 can be increased to 51% by weight or more, allowing the laminated container 100 to be disposed of as paper.

[0046] Furthermore, this embodiment is a method for manufacturing a laminated container 100 comprising a body portion 20 for containing contents, a mouth portion 10 connected to the upper end of the body portion 20, a bottom portion 40 that closes the lower end of the body portion 20, and a label portion 28 that covers at least a part of the body portion 20 from the outside, wherein the label portion 28 is placed inside a blow molding die, and the container portion 22 is blow molded inside the blow molding die, and the label portion 28 is laminated on the outside of the container portion 22 as an in-mold label. The container portion 22 has a laminated structure in which a low-density polyethylene resin layer 22c, an intermediate layer 22b, and a high-density polyethylene resin layer 22a are laminated in that order from the outside. The intermediate layer 22b contains a paper-blended resin which is a polyolefin resin blended with paper components. The layer of the label portion 28 that is attached to the container portion 22 is made of paper with a thickness of 200 μm to 500 μm, a Beck smoothness of 10 to 800 seconds, and the proportion of paper components in the entire laminated container 100 is 51% by weight or more. By adopting this configuration, the proportion of paper components in the entire laminated container 100 can be increased by making the label portion 28 out of paper and also including paper components in the container portion 22 which forms the skeleton of the laminated container 100. Therefore, the entire laminated container 100 can be disposed of as paper waste. Furthermore, by laminating the label portion 28 to the container portion 22 as an in-mold label, the laminated container 100 can be formed by the bottle molding process alone. Therefore, the manufacturing cost of the laminated container 100 having a label portion 28 containing paper components can be reduced.

[0047] While this disclosure has been described based on various drawings and embodiments, it should be noted that those skilled in the art will find it easy to make various modifications and alterations based on this disclosure. Therefore, it should be noted that these modifications and alterations are included within the scope of the present invention. For example, the functions included in each component can be rearranged in a logically consistent manner, and multiple components can be combined into one or separated. It should be understood that these are also included within the scope of the present invention.

[0048] For example, in this embodiment, a male threaded portion 10b is provided on the outer circumferential surface of the opening 10 so that a mounting cap, pump, etc., can be attached by screw engagement, but the embodiment is not limited to this. The opening 10 may also be provided with an annular projection for attaching a mounting cap, pump, etc., by screw engagement, instead of, or together with, the male threaded portion 10b. Alternatively, the opening 10 may be configured without an engagement portion.

[0049] Furthermore, in this embodiment, examples are shown in which the laminated container 100 is formed by blow molding a laminated parison formed by extrusion molding, or by stretch blow molding a laminated preform, but the embodiment is not limited to these. The laminated container 100 may be formed, for example, by two-color molding, or by setting a plurality of preforms in a mold and performing stretch blow molding.

[0050] Furthermore, this disclosure can be broadly applied not only to laminated containers 100 having a body portion 20 in a substantially elliptical cylindrical shape as shown in Figure 1A, but also to containers with a substantially cylindrical or rectangular shape, pouch containers, cup containers, and the like.

[0051] Furthermore, although the container portion 22 of this embodiment is laminated in the order of a low-density polyethylene resin layer 22c, an intermediate layer 22b, and a high-density polyethylene resin layer 22a from the outside, other layers may be provided between these layers. [Examples]

[0052] To verify the drop impact resistance, moisture barrier properties, label transportability / mold retention, swelling resistance, ESCR, and label adhesion of the laminated container 100 of this disclosure, we fabricated and evaluated Examples 1 to 6 and Comparative Examples 1 to 3 (see Table 1) by varying the thickness and Beck smoothness of the label portion 28, and the thickness of the low-density polyethylene resin layer 22c (outer layer), intermediate layer 22b, and high-density polyethylene resin layer 22a (inner layer) of the container portion 22. The conditions common to Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 2. In Table 2, "container surface area" includes the surface area of ​​the mouth portion 10 and the bottom portion 40.

[0053] [Table 1]

[0054] [Table 2]

[0055] In Table 1, "Drop Impact Resistance" was evaluated as "Good" or "Poor" when the stacked container 100 could withstand an impact after being filled with a specified amount of water, sealed, stored at 5°C for 24 hours, and then dropped onto concrete from a height of 1.0 m. "Moisture Barrier Performance" was evaluated as to whether the rate of decrease in water weight over time was within a specified range after being filled with a specified amount of water, sealed, and stored at 40°C. "Label Transportability / Mold Retention Performance" was evaluated as to whether the label section 28 could be accurately removed one by one from the bundle by an automated machine, transported, and fixed in the mold with good positional accuracy. "Swelling Resistance" was evaluated as to whether the rate of increase in the total weight of the bottle was within a specified range after being stored in an environment of 40°C and 75% RH. "ESCR (Environmental Stress Cracking Resistance)" was evaluated as to whether there was any cracking after being filled with 10% of the specified amount of liquid, sealed, and stored at 65°C. "Label adhesion" was evaluated by in-mold molding the label portion 28 and assessing whether the entire label portion 28 adhered to the container portion 22.

[0056] According to the evaluation results shown in Table 1, in Examples 1 to 6, where the thickness of the paper layer of the label portion 28 was 200 μm or more and 500 μm or less, and the Beck smoothness was 10 seconds or more and 800 seconds or less, all evaluation items were rated "Good". However, in Comparative Examples 1 to 3, where at least one of the thickness of the label portion 28 or the Beck smoothness was outside the above range, "Label Adhesion" or "Drop Impact Resistance" was rated "Poor".

[0057] In Comparative Example 1, the label portion 28 was too thin at 94 μm, resulting in low rigidity. Furthermore, the heat from the parison was quickly conducted to the mold through the thin label portion 28, causing the parison's temperature to drop rapidly and reducing the amount of resin that could penetrate to the point of contact with the label portion 28. As a result, the adhesion of the label portion 28 to the container portion 22 was poor.

[0058] In Comparative Example 2, the Beck smoothness was 1500 seconds, and the smoothness of the label portion 28 was too high, resulting in a small amount of resin penetrating the inner surface of the label portion 28. As a result, it is thought that the adhesion of the label portion 28 to the container portion 22 was poor.

[0059] In Comparative Example 3, the label portion 28 was too thick at 600 μm, which resulted in a thinner wall thickness of the container portion 22 at the periphery of the label portion 28, and a larger step in the container portion 22 at the end of the label portion 28. This step caused damage, resulting in poor resistance to drop impact.

[0060] For the reasons stated above, it was found that the specifications of Examples 1 to 6, which resulted in a "good" rating in all evaluation items including "label adhesion" and "drop impact resistance," are necessary, namely, that the thickness of the paper layer in the label section 28 is 200 μm or more and 500 μm or less, and the Beck smoothness of the label section 28 is 10 seconds or more and 800 seconds or less. [Industrial applicability]

[0061] According to this disclosure, it is possible to propose a laminated container 100 that can be disposed of as paper waste as a whole, and a method for manufacturing the laminated container 100. [Explanation of Symbols]

[0062] 10 Mouth 10a opening 10b Male threaded section 20 Torso 22 Container section 22a High-density polyethylene resin layer 22b Middle class 22c Low-density polyethylene resin layer 28 Label section 30 Shoulder 30a R side 40 bottom 40a Pinch-off section 40b R side 100 stacked containers O center axis PL parting line S Containment space

Claims

1. A container having a body for containing contents, a mouth connected to the upper end of the body, and a bottom that closes the lower end of the body, A label portion that covers at least a part of the body from the outside and A stacked container equipped with, The container section has a laminated structure in which a low-density polyethylene resin layer, an intermediate layer, and a high-density polyethylene resin layer are stacked in that order from the outside. The aforementioned intermediate layer contains a paper-based resin, which is a polyolefin resin blended with paper components. The layer attached to the container portion in the label portion is made of paper with a thickness of 200 μm or more and 500 μm or less, and has a Beck smoothness of 10 seconds or more and 800 seconds or less. A laminated container in which the proportion of paper components in the whole of the laminated container is 51% by weight or more.

2. The laminated container according to claim 1, wherein the intermediate layer is a resin layer in which a low-density polyethylene resin is blended with the paper-based resin.

3. The laminated container according to claim 1 or 2, wherein the label portion covers 50% or more of the surface of the container portion.

4. A container having a body for containing contents, a mouth connected to the upper end of the body, and a bottom that closes the lower end of the body, A label portion that covers at least a part of the body from the outside and A method for manufacturing a stacked container, comprising: The label portion is placed inside the blow molding die, In the blow molding die, the container portion is blow-molded, and the label portion is laminated on the outside of the container portion as an in-mold label. Includes, The container section has a laminated structure in which a low-density polyethylene resin layer, an intermediate layer, and a high-density polyethylene resin layer are stacked in that order from the outside. The aforementioned intermediate layer contains a paper-based resin, which is a polyolefin resin blended with paper components. The layer attached to the container portion in the label portion is made of paper with a thickness of 200 μm or more and 500 μm or less, and has a Beck smoothness of 10 to 800 seconds. A method for manufacturing a laminated container, wherein the proportion of paper components in the entire laminated container is 51% by weight or more.

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