Multilayer container

Abstract

To provide a multilayer container capable of easily separating an outer layer and an inner layer.SOLUTION: A multilayer container according to the present invention comprises an outer layer and an inner layer. The inner layer is configured to be separable from the outer layer, and the outer layer is configured to be tearable starting from a tear initiation portion of the outer layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multilayer container. [Background technology]

[0002] Conventionally, multilayer containers having a container body having an outer layer and an inner layer have been known. For example, Patent Document 1 discloses a multilayer container formed by direct blow molding using a multilayer parison corresponding to the inner layer and the outer layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-193023 Summary of the Invention [Problem to be solved by the invention]

[0004] In a multilayer container, when contents remain inside the inner layer after use, or when the outer and inner layers are made of different materials, it is desirable to separate the outer and inner layers when recycling the multilayer container. Therefore, a configuration that allows users to easily separate the outer and inner layers is desirable for such a multilayer container.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a multilayer container in which the outer layer and the inner layer can be easily separated. [Means for solving the problem]

[0006] A multi-layer container according to an exemplary embodiment of the present invention has the following configuration. [1] A multilayer container having an outer layer and an inner layer, wherein the inner layer is configured to be separable from the outer layer, and the outer layer is configured to be tearable starting from the outer layer tear initiation point. [2] A multilayer container as described in [1], wherein the multilayer container is configured such that the container body and the gripping portion are connected via a thin-walled portion, and the outer layer tear initiation portion is configured by the thin-walled portion. [3] A multilayer container according to [1] or [2], comprising a mouth, a body, and a bottom, the mouth being a tubular portion with an open end, the body being positioned adjacent to the mouth on a side farther from the open end than the mouth, the bottom being configured to close the lower end of the body, and the outer layer tear initiation portion being formed by a slit provided in the bottom. [4] A multilayer container according to any one of [1] to [3], wherein the outer layer is composed of a composition containing a resin and talc, the composition contains 45 to 80% by mass of the talc, and the content of the talc is 40% by mass or more relative to the entire multilayer container. [5] The multilayer container according to any one of [1] to [4], wherein the tear strength of the outer layer is 1.4 kgf or less. [Effects of the Invention]

[0007] The multilayer container according to the present invention is characterized in that it is configured to be tearable starting from an outer layer tear initiation portion provided in the outer layer, and by tearing the outer layer from the outer layer tear initiation portion, the outer layer can be easily separated from the inner layer. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view of a multilayer container 1 according to a first embodiment of the present invention, and region A shows a cross section of the multilayer container 1. FIG. [Figure 2] Fig. 2A is a top view of a multilayer container 1 according to a first embodiment of the present invention, and Fig. 2B is an enlarged view of region C in Fig. 2A. [Figure 3] 3A, 3B, and 3C are diagrams showing the process of separating the outer layer 2 and the inner layer 3 of the multilayer container 1 according to the first embodiment of the present invention. [Figure 4]2 is a diagram showing a cross section of a parison 50 and a split mold 40 at a position corresponding to line BB in FIG. 1. FIG. [Figure 5] FIG. 10 is a perspective view of a multilayer container 1 according to a second embodiment of the present invention, seen from the bottom side. [Figure 6] FIG. 10 is a side view of a multilayer container 1 according to a third embodiment of the present invention. [Figure 7] FIG. 1 is a schematic diagram of a test piece used in a tear test. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently. Furthermore, in the following embodiments, elements not specified in the claims are optional elements and can be omitted. Any number of "0"s (for example, one or two) may be added to the end of numerical values ​​disclosed in the following description. For example, one or two "0"s may be added after "1.4" to make it "1.40" or "1.400."

[0010] In the following description, the front, rear, left, right, top and bottom directions are defined as shown in FIGS.

[0011] 1. First embodiment 1.1 Structure of multilayer container 1 Fig. 1 is a side view of a multi-layer container 1. Fig. 2 is a top view of the multi-layer container 1. As shown in Figs. 1 and 2, the multi-layer container 1 comprises a container body 10, an outer layer tear initiation portion 20, and a grip portion 30. Also, as shown in Fig. 1, the multi-layer container 1 comprises an outer layer 2 and an inner layer 3.

[0012] The multilayer container 1 is a container in which the outer layer 2 and the inner layer 3 can be separated by tearing the outer layer 2 using the outer layer tear initiation portion 20 and the grip portion 30, which are connected to the container body 10 of the outer layer 2. Because the outer layer 2 and the inner layer 3 can be separated, the outer layer 2 and the inner layer 3, which are made of different materials, can be easily recycled. Furthermore, once the outer layer 2 and the inner layer 3 are separated, the contents can be used up by crushing only the inner layer 3.

[0013] First, the container body 10 will be described. The container body 10 comprises a mouth 11, a body 12, and a bottom 13. The mouth 11 is a cylindrical portion with an open end, and is provided with an engagement portion 11a at the open end that can be attached to a cap (not shown). The opening of the mouth 11 is closed by attaching the cap to the engagement portion 11a. The engagement portion 11a has any shape that is compatible with the cap to be used. For example, if a stopper-type cap is used, the engagement portion 11a can be configured as an annular protrusion that protrudes in the circumferential direction. Also, for example, if a screw-type cap is used, the engagement portion 11a can be configured as a male screw.

[0014] The body 12 is disposed adjacent to the mouth 11 on the side farther from the open end than the mouth 11. The body 12 is cylindrical and has a larger outer diameter than the mouth 11. In this specification, the outer diameter means the circumscribed circle diameter if the cross section is not circular. The bottom 13 is configured to close the lower end of the body 12.

[0015] As shown in Figure 1, outer layer 2 is the outermost layer in multi-layer container 1, with inner layer 3 located inside it. Inner layer 3 forms an inner bag capable of accommodating contents, and outer layer 2 forms an outer shell that covers the inner bag. Inner layer 3 is configured to be separable from outer layer 2. Inner layer 3 and outer layer 2 each have portions corresponding to mouth 11, body 12, and bottom 13 of container body 10.

[0016] The thickness of the outer layer 2 at the center of the container body 10 in the vertical direction is, for example, 0.1 to 1.0 mm, and preferably 0.2 to 0.7 mm. Specific examples of this thickness include 0.10, 0.15, 0.20, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm, and may be within a range between any two of the values ​​exemplified here. By setting the thickness within this range, the outer layer 2 can be torn while ensuring the strength of the container.

[0017] Next, the outer layer tear initiation portion 20 and the grip portion 30 will be described, mainly with reference to Figures 1 and 2B. The outer layer tear initiation portion 20 according to this embodiment is composed of a thin-walled portion 21. In the multilayer container 1, the container body 10 of the outer layer 2 and the grip portion 30 are connected via the thin-walled portion 21. The outer layer 2 is configured to be tearable starting from the thin-walled portion 21 (outer layer tear initiation portion 20). In this specification, tearable means that the user can tear it manually without using tools such as scissors.

[0018] Due to the characteristics of the method for manufacturing the multilayer container 1 using a split mold 40 by direct blow molding, which will be described later, the thin-walled portion 21 is preferably formed so as to be connected to the container body 10 and extend along the parting line in the vertical direction of the multilayer container 1, as in the thin-walled portion 21 shown in Fig. 1. However, the thin-walled portion 21 can be formed in any position as long as the outer layer 2 can be torn by applying force through the gap between the inner layer 3 and the outer layer 2 when the thin-walled portion 21 is torn.

[0019] 1, the length L1 of the thin-walled portion 21 in the longitudinal direction (the vertical direction of the container body 10) is preferably 20% or more of the length L of the container body 10 in the longitudinal direction. Specifically, the length L1 of the thin-walled portion 21 in the longitudinal direction is, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95% of the length L of the container body 10 in the longitudinal direction, and may be within a range between any two of the values ​​exemplified here or any value greater than or equal to the range. By setting the length L1 of the thin-walled portion 21 in this range, when the thin-walled portion 21 is torn, it becomes easier for a user to insert their fingers between the inner layer 3 and the outer layer 2 and tear the outer layer 2.

[0020] As shown in FIG. 2B, the thickness T1 of the thin-walled portion 21 (the length in the circumferential direction relative to the container body 10) is preferably 0.1 to 1 mm. The thickness T1 of the thin-walled portion 21 is more preferably 0.1 to 0.6 mm. Specifically, the thickness T1 of the thin-walled portion 21 may be, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.7, 0.8, 0.9, or 1.0 mm, or may be within a range between any two of the values ​​exemplified here. By setting the thickness T1 of the thin-walled portion 21 within this range, the thin-walled portion 21 can be easily torn by the user's force and tearing of the thin-walled portion 21 can be prevented under normal use conditions.

[0021] The grip portion 30 is configured to be connected to the container body 10 via the thin-walled portion 21, and is therefore formed to protrude from the container body 10 along the thin-walled portion 21. The grip portion 30 may have any shape as long as it can be grasped by a user as a handle when tearing the outer layer 2. In the example of FIG. 2, the shape of the grip portion 30 is formed in accordance with the shape of the split mold 40, so that the front side of the grip portion 30 is inclined toward the thin-walled portion 21.

[0022] As shown in FIG. 1 , the length L2 of the grip portion 30 in the longitudinal direction (the vertical direction of the container body 10) is preferably 20% or more of the length L of the container body 10 in the longitudinal direction. Specifically, the length L2 of the grip portion 30 in the longitudinal direction is, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95% of the length L of the container body 10 in the longitudinal direction, and may be within a range between any two of the values ​​exemplified here or greater than any one of them. In the illustrated example, the length L2 of the grip portion 30 in the longitudinal direction is the same as the length L1 of the thin-walled portion 21 in the longitudinal direction. However, the length L2 of the grip portion 30 in the longitudinal direction may be longer than the length L1 of the thin-walled portion 21 in the longitudinal direction. In this case, the thin-walled portion 21 can be torn with less force by gripping a portion of the grip portion 30 that is longer than the thin-walled portion 21.

[0023] As shown in FIG. 2B , the length H of the grip portion 30 in the direction protruding from the container body 10 (and in the direction perpendicular to the circumferential direction of the container body 10) is preferably 0.5 to 2 cm, more preferably 1.0 to 1.5 cm. Specifically, the length H of the grip portion 30 in the direction protruding from the container body 10 may be, for example, 0.5, 1.0, 1.5, or 2.0 cm, or may be within a range between any two of the values ​​exemplified here. By setting the dimensions of the grip portion 30 within this range, the user can easily grasp the grip portion 30 and tear the outer layer 2 more easily.

[0024] As shown in FIG. 2B , the thickness T2 of the gripping portion 30 (the length in the circumferential direction relative to the container body 10) is greater than the thickness T1 of the thin-walled portion 21. When the gripping portion 30 has a thickness T2 greater than the thickness T1 of the thin-walled portion 21, the strength of the gripping portion 30 is greater than that of the thin-walled portion 21. If the strength of the gripping portion 30 is weaker than that of the thin-walled portion 21, when a user tears the outer layer 2, the thin-walled portion 21 may not tear but the gripping portion 30 may tear, and the inner layer 3 may not be exposed. With the above configuration, it is possible to prevent the outer layer 2 and the inner layer 3 from becoming difficult to separate due to the inner layer 3 not being exposed.

[0025] The thickness T2 of the grip portion 30 (the length in the circumferential direction relative to the container body 10) is preferably 1 to 5 mm. The thickness T2 of the grip portion 30 is more preferably 1 to 2 mm. Specific examples of the thickness T2 of the grip portion 30 are 1.0, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 3.0, 3.5, 4.0, and 5.0 mm, and may be within a range between any two of the values ​​exemplified here. As will be described in detail later, by setting the thickness T2 of the grip portion 30 within this range, the desired thickness of the thin-walled portion 21 can be ensured during the manufacture of the multilayer container 1.

[0026] Next, the composition used in the multilayer container 1 will be described. The outer layer 2 is composed of a composition containing a resin and talc. Specifically, the composition constituting the outer layer 2 contains, for example, 45 to 80 mass% of talc, and preferably 50 to 70 mass% of talc. The talc content in the composition constituting the outer layer 2 is specifically, for example, 45, 50, 55, 60, 65, 70, 75, or 80 mass%, and may be within a range between any two of the values ​​exemplified here. By forming the outer layer 2 from a composition containing talc, the rigidity of the multilayer container 1 against external forces can be improved. Furthermore, by setting the talc content within the above-mentioned range, the outer layer 2 is easy to tear, and the moldability and strength of the container are not excessively impaired due to an excessive talc content.

[0027] The talc content in the composition constituting the outer layer 2 is preferably 40% by mass or more, and more preferably 51% by mass or more, relative to the total mass of the multilayer container 1. There is no particular upper limit to the range of the talc content relative to the total mass of the multilayer container 1, but since the talc content in the composition constituting the outer layer 2 is 45 to 80% by mass, the talc content relative to the total mass of the multilayer container 1 will be less than 80% by mass.

[0028] The talc content in the composition constituting the outer layer 2 is, for example, 40 to 75 mass%, specifically, for example, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 55, 60, 65, 70, or 75 mass% relative to the entire multilayer container 1, and may be within a range between or equal to any two of the values ​​exemplified here. Because talc does not contain carbon, setting the talc content within this range also makes it possible to reduce the amount of carbon dioxide generated when discarded multilayer containers 1 are incinerated.

[0029] The resin contained in the composition constituting the outer layer 2 preferably includes an olefin-based resin and an olefin-based elastomer. Examples of olefin-based resins include polypropylene (PP), polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE), poly-1-butene, and poly-4-methyl-1-pentene. The olefin-based resin may be a random or block copolymer of α-olefins such as ethylene, propylene, 1-butene, or 4-methyl-1-pentene, or may be a so-called cyclic olefin resin (cycloolefin polymer (COP)) or a copolymer of a cyclic olefin and an α-olefin (a chain olefin), such as a so-called cyclic olefin copolymer (cycloolefin copolymer (COC)). These olefin-based resins may be used alone or in combination of two or more.

[0030] The olefin-based resin is preferably polypropylene, polyethylene, or a mixed resin of polypropylene and polyethylene, and it is preferable that one of these is the main component of the resin contained in the composition constituting the outer layer 2, that is, that it accounts for 50% by mass or more of the total resin. Furthermore, it is preferable to use low-density polyethylene or linear low-density polyethylene as the polyethylene.

[0031] Olefin-based elastomers are thermoplastic elastomers that have polyolefins such as polyethylene and polypropylene as hard segments and rubber components such as ethylene propylene rubber as soft segments. Thermoplastic elastomers are elastomers that soften and become fluid when heated, and are distinguishable from rubbers that do not have this property. Using a resin containing an olefin-based elastomer can improve the strength of the outer layer 2, and in particular, makes the outer layer 2 less likely to crack when the body 12 of the multilayer container 1 is squeezed to dispense the contents.

[0032] Examples of olefin-based elastomers include ethylene-based elastomers such as ethylene-α-olefin copolymers and propylene-based elastomers such as propylene-α-olefin copolymers. These olefin-based base resins may be used alone or in combination of two or more. Furthermore, it is preferable to use an ethylene-based elastomer as the olefin-based elastomer.

[0033] The mass ratio of the olefin-based base resin to the olefin-based elastomer in the resin contained in the composition constituting the outer layer 2 is preferably 40 / 60 to 90 / 10, and more preferably 45 / 65 to 80 / 20. By setting the mass ratio within this range, the strength of the outer layer 2 can be further improved.

[0034] The tear strength of the outer layer 2 is preferably 1.4 kgf or less. The tear strength is preferably, for example, 0.5 to 1.4 kgf. Specific examples of the tear strength include 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, and 1.4 kgf, and the tear strength may be within a range between any two of the values ​​exemplified here or equal to or less than any of the values. By setting the tear strength within this range, the outer layer 2 can be easily torn.

[0035] The composition constituting the inner layer 3 can be any material used as the inner layer of an existing multilayer container 1. However, the talc content in the composition constituting the inner layer 3 is preferably 5% or less. More preferably, the talc content in the composition constituting the inner layer 3 is 1% or less, and even more preferably 0.1% or less. Specifically, the talc content in the composition constituting the inner layer 3 is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0% or less, and may be within a range between any two of the values ​​exemplified here or any value less than or equal to any one of the values. The talc content may be substantially zero. By keeping the talc content within this range, the impact resistance of the multilayer container 1 can be ensured.

[0036] For example, the inner layer 3 may include multiple layers, such as an innermost layer, an adhesive layer, a barrier layer, and an intermediate layer. When the inner layer 3 includes an innermost layer, an adhesive layer, and a barrier layer, these layers are arranged in this order from the inside out. Therefore, the inner surface of the innermost layer comes into contact with the contents.

[0037] The innermost layer is preferably composed of a resin composition containing a polyolefin resin. Examples of polyolefin resins include polyethylenes such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene, polypropylene (PP), poly-1-butene, and poly-4-methyl-1-pentene. The polyolefin resin may also be a random or block copolymer of α-olefins such as ethylene, propylene, 1-butene, or 4-methyl-1-pentene, or may be a so-called cyclic olefin resin (cycloolefin polymer (COP)) or a copolymer of a cyclic olefin and an α-olefin (a chain olefin), such as a so-called cyclic olefin copolymer (cycloolefin copolymer (COC)). These polyolefin resins may be used alone or in combination of two or more.

[0038] The barrier layer is made of a resin with high gas barrier properties. Examples of such resins include ethylene vinyl alcohol copolymer (EVOH: saponified ethylene vinyl acetate copolymer) and aromatic polyamide. By providing a barrier layer, oxidative degradation of the contents due to oxygen permeation can be effectively suppressed.

[0039] The adhesive layer is made of an adhesive resin and is disposed between the innermost layer and the barrier layer. Examples of adhesive resins include acid-modified polyolefin resins (e.g., maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene). By providing the adhesive layer, the adhesion between the innermost layer and the barrier layer is improved. Note that instead of providing an adhesive layer, an adhesive resin may be blended into the barrier layer.

[0040] The internal volume of the multilayer container 1 is not particularly limited, but is preferably 100 mL or less, more preferably 70 mL or less, and even more preferably 50 mL or less. Specific internal volumes of the multilayer container 1 are, for example, 50, 60, 70, 80, 90, or 100 mL, and may be within a range between any two of the values ​​exemplified here or less than any one of these values. If the internal volume is within this range, the impact resistance and moldability of the multilayer container 1 can be ensured.

[0041] The process of tearing the outer layer 2 will be described below with reference to Fig. 3. In Fig. 3, the inner layer 3 is shown shaded for ease of understanding.

[0042] As shown in FIG. 3A, when a user moves the end of the gripping portion 30 along the circumferential direction of the container body 10, the thin-walled portion 21 acts as a starting point to tear the outer layer 2. As shown in FIG. 3B, when the thin-walled portion 21 is torn and the gripping portion 30 is separated from the container body 10, the inner layer 3 is exposed. Next, the user can insert a finger or the like into the gap between the exposed portion of the inner layer 3 and the outer layer 2 and apply force, tearing the container body 10 at the outer layer 2 as shown in FIG. 3C. This action allows the inner layer 3 and the outer layer 2 to be separated. Note that the tearing process shown in FIG. 3 is merely an example, and tearing may be performed in any direction and manner starting from the thin-walled portion 21.

[0043] 1.2 Manufacturing method of the multilayer container 1 The multilayer container 1 can be formed by direct blow molding. In direct blow molding, a molten cylindrical parison 50 extruded from an extruder is sandwiched between split molds 40 and air is blown into the parison 50 to produce the multilayer container 1. The layer structure of the parison 50 is the same as that of the multilayer container 1. The multilayer parison 50 can be formed by coextrusion molding.

[0044] Fig. 4 shows a cross section of the parison 50 and the split mold 40 at a position corresponding to line BB in Fig. 1. The split mold 40 is formed with a container recess 41 corresponding to the shape of the container body 10 and a gripping portion recess 43 corresponding to the shape of the gripping portion 30. The split mold 40 is provided with a pinch-off portion 42 between the container recess 41 and the gripping portion recess 43.

[0045] When the parison 50 is sandwiched between the split mold 40, it is positioned so that it straddles the container recess 41 and the gripping portion recess 43. As a result, the parison 50 is sandwiched between the pinch-off portions 42, forming the thin-walled portion 21. In this manner, a multi-layer container 1 can be formed that includes the container body 10, the thin-walled portion 21, and the gripping portion 30. The parison 50 shown in Figure 4 shows the state after air has been blown in, and the same reference numerals are used to denote the portions of the parison 50 that correspond to the outer layer 2, inner layer 3, thin-walled portion 21, and gripping portion 30, respectively.

[0046] If the depth of the gripping recess 43 is too shallow, the molten resin may not be able to be contained in the gripping recess 43 during mold clamping, which may affect the thickness of the thin-walled portion 21 formed by the pinch-off portion 42. Therefore, the gripping recess 43 is formed to a depth that allows the aforementioned range of thickness T2 of the gripping portion 30 to be achieved. In addition, a parting surface 44 of the pair of split molds 40 is provided on the outer periphery of the container recess 41.

[0047] 2. Second embodiment A second embodiment of the present invention will be described using Figure 5. This embodiment is similar to the first embodiment, and the content described in the first embodiment can also be applied to this embodiment as long as it does not contradict the spirit of the first embodiment. The main differences between this embodiment and the first embodiment are the structure of the outer layer tear initiation portion 20 and the absence of the grip portion 30. The following description will focus on these differences.

[0048] Fig. 5 is a perspective view from the bottom side of a multilayer container 1 according to a second embodiment of the present invention. As shown in Fig. 5, in this embodiment, the outer layer tear initiation portion 20 is formed by a slit provided in the bottom portion 13. In this embodiment, the user can insert their finger between the outer layer 2 and the inner layer 3 through the slit and tear the outer layer 2 from the bottom portion 13, thereby separating the outer layer 2 and the inner layer 3.

[0049] The length of the slit is preferably 50% or more of the outer diameter of the bottom 13 of the multilayer container 1. Specifically, the length of the slit is, for example, 50, 60, 70, 80, or 90% of the outer diameter of the bottom 13, and may be within a range between any two of the values ​​exemplified here or any value greater than or equal to that range. Setting the slit length within this range makes it easier for a user to insert their finger into the slit and tear the outer layer 2.

[0050] In the multilayer container 1 of the second embodiment, unlike the first embodiment, a thin-walled portion 21 and a gripping portion 30 protruding from the outer layer 2 are not formed, so that the outer layer 2 and the inner layer 3 can be easily separated without compromising the design of the container as a whole.

[0051] 3. Third embodiment A third embodiment of the present invention will be described using Figure 6. This embodiment is similar to the first embodiment, and the content described in the first embodiment can also be applied to this embodiment as long as it does not contradict the spirit of the first embodiment. The main difference between this embodiment and the first embodiment is the structure of the outer layer tear initiation portion 20. The following description will focus on these differences.

[0052] Fig. 6 is a side view of a multilayer container 1 according to a third embodiment. In this embodiment, too, a thin-walled portion 21 is formed as the outer layer tear initiation portion 20. In the multilayer container 1 according to this embodiment, the thin-walled portion 21 and the grip portion 30 are configured so as not to protrude from the circumscribed circle of the body portion 12. In the example of Fig. 6, when viewed from the perspective of Fig. 6, the right end side of the body portion 12, the thin-walled portion 21, and the grip portion 30 are arranged in a straight line. In other words, the right side of the body portion 12 is formed in a hollowed-out shape, and the thin-walled portion 21 and the grip portion 30 are formed in the hollowed-out portion.

[0053] In this embodiment, as in the above-described embodiment, when the gripping portion 30 is grasped, the outer layer 2 is torn starting from the thin-walled portion 21, thereby exposing the inner layer 3. After the inner layer 3 is exposed, the user can insert their fingers between the outer layer 2 and the inner layer 3 to tear the outer layer 2.

[0054] Unlike the first embodiment, the multilayer container 1 of the third embodiment does not have a gripping portion 30 or the like protruding from the outer layer 2, making it possible to easily separate the outer layer 2 and the inner layer 3 without compromising the design of the container as a whole.

[0055] 4. Other Embodiments The multilayer containers 1 of the first to third embodiments each have one outer layer tear initiation portion 20, but multiple outer layer tear initiation portions 20 may be formed, or the outer layer tear initiation portions 20 of the first to third embodiments may be combined.

[0056] The multilayer container 1 may be a so-called peelable laminate container configured so that the inner layer 3 peels from the outer layer 2 as the content decreases in the body 12. In this case, an outside air inlet is provided in the body 12 of the multilayer container 1. The outside air inlet is, for example, a through-hole (outside air inlet) that penetrates the outer layer 2, and outside air can be introduced into the intermediate space between the outer layer 2 and the inner layer 3 through the outside air inlet. In addition, a check valve may be provided in the cap, allowing the content to be discharged but preventing outside air from flowing into the multilayer container 1. [Example]

[0057] (1) Overview In the multilayer container 1 shown in Fig. 1, only the shape of the container body 10 portion of the outer layer 2 of the multilayer container 1 was produced by direct blow molding, and tear strength was measured. As an example, five containers according to the present invention produced using talc (hereinafter referred to as talc containers), and five containers produced using low-density polyethylene (hereinafter referred to as LDPE containers) and five containers produced using polypropylene and linear low-density polyethylene (hereinafter referred to as PP+LLDPE containers) were produced as comparative examples, and their tear strengths were compared.

[0058] The compositions of the examples and comparative examples used in this example are as follows: Examples 1 to 5: Talc content 60% by mass, PP 30% by mass, ethylene-α-olefin copolymer 10% Comparative examples 1 to 5: LDPE 100% by mass Comparative Examples 6 to 10: PP70% by mass, LLDPE30% by mass

[0059] <Measurement of tear strength> The tear strength was measured in accordance with JIS K 7128-1:1998. Specifically, the barrel portion 12 of the container body 10 of each outer layer 2 of the manufactured multilayer container 1 was cut into a 20 mm × 60 mm strip to prepare a test specimen as shown in Figure 7. A 10 mm slit was formed in the longitudinal direction of the test specimen from the center of the short side of one end of the test specimen. A tensile test was performed by gripping each leg of the slit with a jig, fixing one leg, and pulling the other leg. The pulling speed was 200 mm / min. The tear strength of the material was measured using the average force required to completely tear the test specimen in the longitudinal direction.

[0060] (2) Results The results are shown in Table 1. [Table 1]

[0061] The tear strength of the LDPE container was 1.5-2.1 kgf, while the tear strength of the talc container was 0.6-1.3 kgf. Therefore, the talc container can be torn apart with less force than the LDPE container. Furthermore, the PP+LLDPE container stretched during the tensile test, making it impossible to tear and measure. From the above, it was found that the talc container can be torn apart more easily than the LDPE and PP+LLDPE containers. [Explanation of symbols]

[0062] 1:Multilayer container 2: Outer layer 3: Inner layer 10: Container body 11: Mouth 11a: Engagement part 12: Torso 13: Bottom 20: Outer layer tearing start part 21: Thin section 30: Grip part 40: Split mold 41: Container recess 42: Pinch-off section 43: Recessed portion for gripping 44: Parting surface 50: Parison

Claims

1. A multilayer container having an outer layer and an inner layer, The inner layer is configured to be separable from the outer layer, The outer layer is configured to be tearable starting from an outer layer tear initiation portion.

2. The multilayer container according to claim 1, The multilayer container is configured such that a container body and a gripping portion are connected via a thin-walled portion, A multilayer container, wherein the outer layer tear initiation portion is constituted by the thin-walled portion.

3. The multilayer container according to claim 1, The multilayer container has a mouth, a body, and a bottom, the mouth is a tubular portion having an open end, the body is disposed adjacent to the mouth on a side farther from the open end than the mouth, and the bottom is configured to close the lower end of the body, A multilayer container, wherein the outer layer tear initiation portion is constituted by a slit provided in the bottom portion.

4. The multilayer container according to any one of claims 1 to 3, the outer layer is made of a composition containing a resin and talc, The composition contains 45 to 80% by mass of the talc, A multilayer container, wherein the talc content is 40% by mass or more based on the entire multilayer container.

5. The multilayer container according to any one of claims 1 to 3, A multilayer container, wherein the outer layer has a tear strength of 1.4 kgf or less.

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