laminated container

Abstract

To provide a laminated container that has chemical resistance and improved impact resistance.SOLUTION: A laminated container 100 according to the present disclosure has a body 20 containing contents, a mouth 10 connected to an upper end of the body 20, and a bottom 40 closing a lower end of the body 20, and is provided with a laminated structure 24. The laminated structure 24 comprises: an intermediate layer 24b made mainly of polyolefin resin; an innermost layer 24a covering the intermediate layer 24b from the inside and having better chemical resistance to organic solvents excluding alcohols than the intermediate layer 24b; and an outermost layer 24c covering the intermediate layer 24b from the outside and having better chemical resistance to organic solvents excluding alcohols than the intermediate layer 24b. The intermediate layer 24b is adjacent to at least one of the innermost layer 24a and the outermost layer 24c, and contains 25 wt.% or more and 45 wt.% or less of adhesive resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to laminated containers. [Background technology]

[0002] Conventionally, containers for storing medicines, etc., have been proposed that are formed with a single layer structure of, for example, glass or synthetic resin with excellent chemical resistance. For example, Patent Document 1 discloses a nail polish container that has a single layer structure of synthetic resin with excellent chemical resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-182831 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the nail polish container described in Patent Document 1 has a single-layer structure, and therefore may not have sufficient impact resistance when dropped, and in this respect there is room for improvement.

[0005] The present disclosure proposes a laminated container that has chemical resistance and improved impact resistance. [Means for solving the problem]

[0006] In order to solve the above problems, the laminated container of the present disclosure comprises: [1] A laminated container having a body portion for accommodating contents, a mouth portion connected to an upper end portion of the body portion, and a bottom portion closing a lower end portion of the body portion, and having a laminated structure, The laminated structure is an intermediate layer primarily made of polyolefin resin; an innermost layer that covers the intermediate layer from the inside and has better chemical resistance to organic solvents other than alcohols than the intermediate layer; an outermost layer that covers the intermediate layer from the outside and has better chemical resistance to organic solvents except for alcohols than the intermediate layer; Equipped with The intermediate layer is adjacent to at least one of the innermost layer and the outermost layer, and contains an adhesive resin in an amount of 25% by weight or more and 45% by weight or less. fruit, The innermost layer and the outermost layer are resin layers whose main material is an ethylene-vinyl alcohol copolymer resin or a nylon resin. It is characterized by:

[0007] Further, the laminated container of the present disclosure is [2] In the above configuration [1], it is preferable that the intermediate layer is adjacent to both the innermost layer and the outermost layer.

[0008] Further, the laminated container of the present disclosure is [3] In the above configuration [1] or [2], it is preferable that the radial thickness of the innermost layer and the outermost layer is 60 μm or more and 200 μm or less. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to propose a laminated container that has chemical resistance and improved impact resistance. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a front partial cross-sectional view of a laminated container according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a detailed view of part A in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described in more detail below with reference to the drawings.

[0013] FIG. 1 is a front view showing the configuration of a stacked container 100 according to one embodiment of the present disclosure. The stacked container 100 includes a body 20 having a substantially circular shape in a plan view and forming a storage space S for contents, a mouth 10 connected to the upper end of the body 20 via a shoulder 30 and forming an opening 10a on the inside for supplying and discharging the contents, and a bottom 40 closing the lower end of the body 20. As shown in FIG. 1, the outer peripheral surface of the mouth 10 is provided with a male thread 10b that allows a cap, a pump, or the like to be attached by threaded engagement. The entire area of ​​the mouth 10, shoulder 30, body 20, and bottom 40 in FIG. 1 is formed by a stacked structure 24 shown in cross section in FIG. 2.

[0014] In this specification, claims, and drawings, the side where the mouth portion 10 is located is referred to as the upper side (upper side in FIG. 1), and the side where the bottom portion 40 is located is referred to as the lower side (lower side in FIG. 1). In addition, in describing the layer structure of the stacked container 100, the storage space S side is referred to as the inner side, and the side of the outermost layer 24c is referred to as the outer side. Furthermore, the radially outer side refers to the direction away from the central axis O along a straight line that passes through the central axis O of the stacked container 100 in FIG. 1 and is perpendicular to the central axis O, and the radially inner side refers to the direction toward the central axis O along that straight line.

[0015] As shown in FIG. 2, the body 20 of the laminated container 100 forms a storage space S for contents. The body 20 includes an intermediate layer 24b, an innermost layer 24a that covers the intermediate layer 24b from the inside and has better chemical resistance than the intermediate layer 24b, and an outermost layer 24c that covers the intermediate layer 24b from the outside and has better chemical resistance than the intermediate layer 24b. In this specification and claims, "excellent chemical resistance" means that, in a chemical resistance test conforming to JIS K 7114:2001, when an organic solvent other than alcohols is used as the contents, no change in appearance is observed in the innermost layer 24a or the outermost layer 24c after 7 days at 23°C, and the weight increase of the innermost layer 24a or the outermost layer 24c is 0.1% or less. The contents may be, for example, organic solvents such as hydrocarbons (e.g., toluene) as well as organic solvents such as ketones, esters, and ethers.

[0016] The intermediate layer 24b is mainly made of a polyolefin resin, and in this embodiment, the main material is a polyethylene (PE) resin. However, other polyolefin resins such as a polypropylene (PP) resin may also be used.

[0017] In this embodiment, the intermediate layer 24b has a thickness of approximately 630 μm. The intermediate layer 24b is formed thicker than the innermost layer 24a and the outermost layer 24c, and the intermediate layer 24b mainly forms the bottle-like shape of the laminated container 100.

[0018] In this embodiment, the intermediate layer 24b contains 25% by weight or more and 45% by weight or less of an adhesive resin. This configuration allows the innermost layer 24a and the outermost layer 24c to be fixed without an adhesive layer, even if the innermost layer 24a and the outermost layer 24c are made of a material that has low compatibility with the intermediate layer 24b and is prone to peeling, such as ethylene-vinyl alcohol copolymer resin (EVOH) or nylon resin. In this embodiment, no adhesive layer is provided between the intermediate layer 24b and the innermost layer 24a or between the intermediate layer 24b and the outermost layer 24c. Instead, the innermost layer 24a and the outermost layer 24c are fixed to the intermediate layer 24b by the adhesive resin contained in the intermediate layer 24b. In other words, the intermediate layer 24b is disposed adjacent to each of the innermost layer 24a and the outermost layer 24c. However, the present invention is not limited to this embodiment, and at least one of the innermost layer 24a and the outermost layer 24c may be fixed by the adhesive resin contained in the intermediate layer 24b without using an adhesive layer, and may be disposed adjacent to the intermediate layer 24b. In other words, the other of the innermost layer 24a and the outermost layer 24c may be fixed to the intermediate layer 24b via an adhesive layer.

[0019] If the intermediate layer 24b contains less than 25% by weight of adhesive resin, the innermost layer 24a or the outermost layer 24c, which is adjacent to the intermediate layer 24b without an adhesive layer interposed therebetween, will not be sufficiently fixed to the intermediate layer 24b, and may peel off due to slight external factors such as impact or temperature change. Furthermore, if the intermediate layer 24b contains more than 45% by weight of adhesive resin, the innermost layer 24a and the outermost layer 24c will be fixed to the intermediate layer 24b with sufficient strength, but the fluidity of the resin in the intermediate layer 24b when molding the laminated container 100 may be reduced, which may adversely affect the moldability of the laminated container 100. Therefore, it is preferable that the intermediate layer 24b contain 25% to 45% by weight of adhesive resin. Note that the adhesive resin content (25% to 45% by weight) refers to the proportion of adhesive resin in the intermediate layer 24b, not the proportion of adhesive resin in the entire laminated container 100.

[0020] In this embodiment, the adhesive resin blended into the intermediate layer 24b may be, for example, a modified polyolefin resin such as Admer (registered trademark) manufactured by Mitsui Chemicals, Inc., but is not limited to this.

[0021] In this embodiment, the intermediate layer 24b is colored with a brown masterbatch for the purpose of blocking light. The weight ratio of the main material (polyolefin resin) to the masterbatch in the intermediate layer 24b is approximately 15:1.

[0022] In this embodiment, the innermost layer 24a and the outermost layer 24c are formed of a material primarily composed of ethylene-vinyl alcohol copolymer resin (EVOH). Furthermore, in this embodiment, the thickness of the innermost layer 24a at approximately the center height of the barrel 20 is approximately 150 μm, and the thickness of the outermost layer 24c is approximately 80 μm. Because the innermost layer 24a is constantly exposed to contents such as organic solvents, it is configured to be thicker than the outermost layer 24c to prevent the contents from affecting the middle layer 24b. Taking into consideration manufacturing efficiency and the like, the innermost layer 24a and the outermost layer 24c may be configured to have the same thickness, or the outermost layer 24c may be configured to be thicker than the innermost layer 24a.

[0023] In this embodiment, the EVOH used in the innermost layer 24a and the outermost layer 24c contains approximately 44 mol% ethylene. The ethylene content of the EVOH used in the innermost layer 24a and the outermost layer 24c is preferably 40 mol% or more and 50 mol% or less. From the viewpoint of improving adhesion between the intermediate layer 24b and the innermost layer 24a or the outermost layer 24c, the ethylene content of the EVOH is preferably 40 mol% or more, and from the viewpoint of ensuring chemical resistance, the ethylene content of the EVOH is preferably 50 mol% or less. This configuration can improve adhesion between the intermediate layer 24b and the innermost layer 24a or the outermost layer 24c while ensuring the chemical resistance of the laminated container 100.

[0024] The thickness of the innermost layer 24a and the outermost layer 24c in the body portion 20 is preferably 60 μm or more and 200 μm or less. If the thickness of the innermost layer 24a and the outermost layer 24c is less than 60 μm, sufficient chemical resistance may not be ensured. Therefore, the thickness of the innermost layer 24a and the outermost layer 24c is preferably 60 μm or more. Furthermore, if the thickness of the innermost layer 24a and the outermost layer 24c exceeds 200 μm, there is a possibility that the moldability of the laminated container 100 may be adversely affected, such as poor adhesion with the intermediate layer 24b due to differences in thermal shrinkage rates. Therefore, the thickness of the innermost layer 24a and the outermost layer 24c is preferably 200 μm or less.

[0025] In this embodiment, EVOH having the same ethylene content is used for the innermost layer 24a and the outermost layer 24c, but this is not limited to this embodiment. For example, if the intermediate layer 24b and the innermost layer 24a are fixed via an adhesive layer while the intermediate layer 24b and the outermost layer 24c are adjacently disposed without an adhesive layer, the ethylene content of the EVOH constituting the outermost layer 24c may be higher than that of the innermost layer 24a to ensure reliable adhesion between the intermediate layer 24b and the outermost layer 24c even without an adhesive layer. Furthermore, the innermost layer 24a may be made of EVOH while the outermost layer 24c may be made of different chemical-resistant resins, such as nylon resin, for example.

[0026] The intermediate layer 24b, which forms the skeleton of the laminated container 100, can be formed from a resin primarily made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP). For example, when polyethylene is used for the intermediate layer 24b, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or high-density polyethylene resin (HDPE) can be used, and when HDPE or PP is used, high rigidity can be imparted to the laminated container 100. Furthermore, the intermediate layer 24b may be made of a virgin polyolefin resin, or a resin layer made by mixing a virgin material with a recycled material. Furthermore, a layer of virgin material and a layer containing a recycled material can be laminated. Furthermore, the intermediate layer 24b may be made of only recycled material.

[0027] The bottom 40 is provided with a recess 43 that is raised higher than the peripheral edge, and as shown in FIG. 1, the recess 43 is provided with a pinch-off portion that extends in the left-right direction of the figure.

[0028] The laminated structure 24 of the present embodiment, which includes the innermost layer 24a, the intermediate layer 24b, and the outermost layer 24c, is formed by forming a laminated parison in which the innermost layer 24a, the intermediate layer 24b, and the outermost layer 24c are laminated by extrusion molding, and then performing blow molding on the laminated parison. The pinch-off portion is formed by cutting off the innermost layer 24a, the intermediate layer 24b, and the outermost layer 24c using a split mold for blow molding.

[0029] The laminated container 100 having this laminated structure 24 has been described based on an example in which a laminated parison in which the innermost layer 24a, the middle layer 24b, and the outermost layer 24c are laminated by extrusion molding is formed, and then the laminated parison is blow molded, but the laminated container 100 is not limited to this embodiment. The laminated container 100 may also be formed by stretch blow molding a laminated preform in which the innermost layer 24a, the middle layer 24b, and the outermost layer 24c are laminated.

[0030] As described above, the laminated container 100 of this embodiment has a body 20 that accommodates the contents, a mouth 10 that is continuous with the upper end of the body 20, and a bottom 40 that closes the lower end of the body 20, and is a laminated container 100 that has a laminated structure 24. The laminated structure 24 includes an intermediate layer 24b that is primarily made of a polyolefin resin, an innermost layer 24a that covers the intermediate layer 24b from the inside and has better chemical resistance to organic solvents other than alcohols than the intermediate layer 24b, and an outermost layer 24c that covers the intermediate layer 24b from the outside and has better chemical resistance to organic solvents other than alcohols than the intermediate layer 24b. The intermediate layer 24b is adjacent to at least one of the innermost layer 24a and the outermost layer 24c, and is configured to contain 25% by weight to 45% by weight of an adhesive resin. By adopting such a configuration, the chemical resistance of the laminated container 100 can be improved by covering the intermediate layer 24b with the innermost layer 24a and the outermost layer 24c of the laminated structure 24, which have better chemical resistance than the intermediate layer 24b. Furthermore, by providing the laminated container 100 with a laminated structure 24 containing an adhesive resin, the impact absorption properties of the adhesive resin and the laminated structure itself can suppress material scattering and improve the impact resistance of the laminated container 100. Furthermore, by including an adhesive resin in the intermediate layer 24b, at least one of the innermost layer 24a and the outermost layer 24c can be disposed adjacent to the intermediate layer 24b without an adhesive layer, thereby simplifying the structure and manufacturing process of the laminated container 100. Furthermore, by eliminating the adhesive layer, it is easier to ensure the thickness of the chemically resistant innermost layer 24a and the outermost layer 24c without changing the thickness of the laminated container 100. Therefore, the chemical resistance of the laminated container 100 can be improved.

[0031] In this embodiment, the intermediate layer 24b is configured to be adjacent to each of the innermost layer 24a and the outermost layer 24c. By adopting such a configuration, both the innermost layer 24a and the outermost layer 24c can be disposed adjacent to the intermediate layer 24b without an adhesive layer, thereby further simplifying the structure and manufacturing process of the stacked container 100. Furthermore, by further reducing the adhesive layer, it is easier to ensure the thickness of the chemical-resistant innermost layer 24a and outermost layer 24c. Therefore, the chemical resistance of the stacked container 100 can be further improved.

[0032] In this embodiment, the radial thicknesses of the innermost layer 24a and the outermost layer 24c are each set to 60 μm or more and 200 μm or less. By adopting such a configuration, the chemical resistance of the innermost layer 24a and the outermost layer 24c can be further improved, and the formability of the laminated container 100 can be improved.

[0033] In this embodiment, the innermost layer 24a and the outermost layer 24c are made of resin layers primarily made of ethylene-vinyl alcohol copolymer resin or nylon resin, which improves chemical resistance to organic solvents other than alcohols.

[0034] Alternatively, the intermediate layer 24b may be fixed to one of the innermost layer 24a and the outermost layer 24c via an adhesive layer, and the intermediate layer 24b may be disposed adjacent to the other of the innermost layer 24a and the outermost layer 24c without an adhesive layer, so that the ethylene content of the EVOH constituting the other of the innermost layer 24a and the outermost layer 24c is higher than that of the one of the innermost layer 24a and the outermost layer 24c. By adopting such a configuration, the intermediate layer 24b and the other of the innermost layer 24a and the outermost layer 24c can be reliably bonded to each other even without an adhesive layer.

[0035] Although the present disclosure has been described based on various drawings and examples, it should be noted that those skilled in the art can easily make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included in the scope of the present invention. For example, the functions included in each component can be rearranged so as not to cause logical inconsistencies, and multiple components can be combined into one or divided. It should be understood that these modifications and alterations are also included in the scope of the present invention.

[0036] For example, in this embodiment, the outer peripheral surface of the mouth portion 10 is provided with a male thread portion 10b so that an attachment cap, pump, etc. can be attached by threaded engagement, but this is not limited to this embodiment. The mouth portion 10 may be provided with an annular protrusion for attaching an attachment cap, pump, etc. by stopper engagement instead of or in addition to the male thread portion 10b. Also, the mouth portion 10 may be configured without an engagement portion.

[0037] In addition, in the present embodiment, an example has been 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 present invention is not limited to these forms. The laminated container 100 may be formed, for example, by two-color molding, or by setting multiple preforms in a mold and performing stretch blow molding. Furthermore, the laminated structure 24 of the innermost layer 24a, the intermediate layer 24b, and the outermost layer 24c can also be formed by a method other than extrusion molding.

[0038] The present disclosure is not limited to a laminated container 100 in which the body 20 has a substantially circular shape in plan view, but may also have a substantially elliptical shape or a flat shape simply having a major axis and a minor axis. It can also be widely applied to rectangular containers, pouch containers, cup containers, and the like. [Industrial Applicability]

[0039] According to the present disclosure, it is possible to propose a laminated container 100 that has chemical resistance and improved impact resistance. [Explanation of symbols]

[0040] 10. Mouth 10a Opening 10b male ねじbe 20 trunk 24. Layered Structures 24a Innermost layer 24b Intermediate Layer 24c outermost layer 30 Shoulders 40 Bottom 43 alcove 100 stacked containers O Central axis S containment space

Claims

1. A laminated container having a body portion for accommodating contents, a mouth portion connected to an upper end portion of the body portion, and a bottom portion closing a lower end portion of the body portion, and having a laminated structure, The laminated structure is an intermediate layer primarily made of polyolefin resin; an innermost layer that covers the intermediate layer from the inside and has better chemical resistance to organic solvents other than alcohols than the intermediate layer; an outermost layer that covers the intermediate layer from the outside and has better chemical resistance to organic solvents except for alcohols than the intermediate layer; Equipped with the intermediate layer is adjacent to at least one of the innermost layer and the outermost layer, and contains 25% by weight or more and 45% by weight or less of an adhesive resin; The laminated container, wherein the innermost layer and the outermost layer are resin layers whose main material is an ethylene-vinyl alcohol copolymer resin or a nylon resin.

2. The laminated container according to claim 1 , wherein the intermediate layer is adjacent to each of the innermost layer and the outermost layer.

3. 3. The laminated container according to claim 1, wherein the radial thickness of the innermost layer and the radial thickness of the outermost layer are each 60 μm or more and 200 μm or less.

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