Laminated container, laminated container with contents, and method for manufacturing a laminated container

Abstract

The present invention provides a new laminated container, a laminated container filled with contents, and a method for manufacturing a laminated container, which can suppress the occurrence of crazing while improving chemical resistance. [Solution] The laminated container 1 of the present disclosure is a resin laminated container 1 comprising a cylindrical mouth portion 2 and a bottomed cylindrical body portion 3 provided below the mouth portion 2, wherein the body portion 3 has an inner layer 4 that partitions and forms a storage space M for contents and an outer layer 5 provided on the outer surface side of the inner layer 4, and the inner layer 4 is composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, wherein the nylon blend material contains 40% by weight or more and 60% by weight or less of crystalline nylon resin.

Description

[[Technical Field]]

[0001] The present disclosure relates to a laminated container, a laminated container containing contents, and a method for manufacturing a laminated container. [[Background Art]]

[0002] Conventionally, as a container for accommodating contents such as nail polish, a container having a cylindrical mouth portion and a bottomed cylindrical body portion connected below the mouth portion has been used. Further, as such a container, glass bottles are widely used. A cap provided with a brush-shaped applicator can be attached to the mouth of the container, and by closing the cap, the brush-shaped applicator is immersed in the contents inside the container body. According to such a container, only by removing the cap from the mouth of the container, the content such as nail polish adhering to the brush-shaped applicator can be applied to the application target portion.

[0003] Further, as a nail polish container using a material other than a glass bottle, a laminated container has been developed which is excellent in resistance to chemicals such as nail polish and uses transparent amorphous nylon as the material of the inner layer (for example, Patent Document 1). [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Patent No. 7058915 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] However, in the laminated container described in Patent Document 1, since the amorphous nylon used as the inner layer material has a high water absorption rate, the moisture content of the inner layer increases due to aging during storage. When the moisture content of the inner layer increases, chemical resistance decreases, and the content such as nail polish may permeate into stress concentration sites to cause crazing, which is the formation of fine cracks. Therefore, there is still room for improvement in this respect.

[0006] This disclosure has been made in view of these issues, and its purpose is to provide a new laminated container, a laminated container with contents, and a method for manufacturing a laminated container that can suppress the occurrence of crazing while improving chemical resistance. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the laminated container of this disclosure is [1] A resin laminated container comprising a cylindrical opening and a bottomed cylindrical body provided below the opening, The body portion has an inner layer that partitions and forms a space for containing the contents, and an outer layer provided on the outer surface side of the inner layer. The inner layer is composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, and the nylon blend material is characterized in that it contains 40% by weight or more and 60% by weight or less of crystalline nylon resin.

[0008] Furthermore, the laminated container of this disclosure is [2] In the configuration described in [1] above, the outer layer is preferably made of PET resin.

[0009] Furthermore, the laminated container of this disclosure is [3] In the configuration described in [1] or [2] above, it is preferable that the thickness of the inner layer is thinner than the thickness of the outer layer.

[0010] Furthermore, in order to solve the above-mentioned problems, the laminated container containing contents of this disclosure is, [4] A laminated container containing contents, comprising a laminated container as described in any of [1] to [3] above, and contents contained in the storage space of the laminated container, The contents are characterized in that they mainly consist of at least one of ethyl acetate, butyl acetate, toluene, and nitrocellulose, and the alcohol component is 15% by weight or less.

[0011] Furthermore, in order to solve the above-mentioned problems, the manufacturing method of the laminated container of this disclosure is [5] A primary preform molding process in which a primary preform having a mouth portion and a main body portion is formed by injection molding using a first resin, A secondary preform molding step is performed in which a secondary preform is formed by injection molding in which the outer surface of the main body of the primary preform is coated with a second resin, A preheating step of heating the secondary preform to a preheating temperature that allows for blow molding, The process includes a blow molding step in which a laminated container is formed by blow molding using the secondary preform heated in the preheating step, The moldable temperature of the first resin alone is higher than the moldable temperature of the second resin alone, and the preheating temperature is equal to or greater than the moldable temperature of the second resin alone, and equal to or less than the moldable temperature of the first resin alone. The first resin is composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, and the nylon blend material is characterized in that it contains 40% by weight or more and 60% by weight or less of crystalline nylon resin.

[0012] Furthermore, the manufacturing method of the laminated container described herein is [6] In the configuration described in [5] above, the second resin is preferably made of PET resin.

[0013] Furthermore, the manufacturing method of the laminated container described herein is [7] In the configuration described in [5] or [6] above, it is preferable that the thickness of the first resin layer, which constitutes the main body of the secondary preform, is thinner than the thickness of the second resin layer, which constitutes the second resin. [Effects of the Invention]

[0014] According to the present disclosure, a novel laminated container, a laminated container containing contents, and a method for manufacturing a laminated container that can improve chemical resistance while suppressing the occurrence of crazing can be provided. [Brief Description of the Drawings]

[0015] [Figure 1] It is a front view showing a laminated container which is one embodiment of the present disclosure, and a part thereof is shown in cross-section. [Figure 2] It is a plan view of the laminated container in FIG. 1. [Figure 3] It is a flow chart showing the implementation procedure of a method for manufacturing a laminated container which is one embodiment of the present disclosure. [Figure 4] It is a cross-sectional view showing a primary preform in the molding process of the laminated container in FIG. 1. [Figure 5] It is a cross-sectional view showing a secondary preform in the molding process of the laminated container in FIG. 1. [Mode for Carrying Out the Invention]

[0016] Hereinafter, the present disclosure will be described more specifically with reference to the drawings. In the present specification, claims, abstract, and drawings, the terms "upward direction" and "downward direction" respectively refer to the vertically upward direction and the vertically downward direction when the laminated container 1 is in an upright posture as shown in FIG. 1; the side where the mouth portion 2 is located with respect to the body portion 3 of the laminated container 1 is defined as the upper side, and the side where the body portion 3 is located with respect to the mouth portion 2 is defined as the lower side. In addition, the radially outer side is the direction away from the central axis O along a straight line that passes through the central axis O of the laminated container 1 in FIG. 1 and is perpendicular to the central axis O, and the radially inner side means the direction approaching the central axis O along the straight line. In addition, the circumferential direction is the direction of rotation around the central axis O.

[0017] As shown in FIG. 1, the laminated container 1, which is one embodiment of the present disclosure, is made of resin, and includes a cylindrical mouth portion 2 having an upper end opening 2a, and a bottomed cylindrical body portion 3 continuous below the mouth portion 2.

[0018] The outer circumferential surface of the opening 2 is provided with a male threaded portion 2b, and is configured to allow the attachment of a cap or the like having a female threaded portion on its inner circumferential surface. A neck ring 2c is provided below the male threaded portion 2b (at the lower end of the opening 2).

[0019] Below the opening 2, the body 3 is integrally connected via the shoulder portion 3b. The body 3 consists of a cylindrical portion 3a and a bottom portion 3c that closes the lower end of the cylindrical portion 3a. The shape of the body 3 is not limited to the illustrated example and can be changed as appropriate. For example, the cylindrical portion 3a in the illustrated example is formed in the shape of a rectangular tube with a cross-section perpendicular to the central axis O (the central axis of the stacked container 1) being square (see Figure 2), but it is not limited to this, and the cross-section may be circular, elliptical, or other polygonal. The shape of the bottom portion 3c can also be changed as appropriate; for example, it can be a shape in which a dome-shaped recess is provided inside the flat outer edge that constitutes the contact surface.

[0020] The shoulder portion 3b connecting the mouth portion 2 and the body portion 3, as shown in Figure 1, comprises an inclined portion 3b1 that slopes radially outward toward the downward direction and a vertical portion 3b2 that hangs down from the lower end of the inclined portion 3b1. The connection between the inclined portion 3b1 and the vertical portion 3b2 is chamfered with a rounded edge. Furthermore, the vertical portion 3b2 is formed to have a smaller radial width than the cylindrical portion 3a of the body portion 3, and a stepped portion 3b4 with a discontinuous radial width is formed at the boundary between the vertical portion 3b2 and the cylindrical portion 3a, as shown in Figure 1.

[0021] As shown in Figure 1, the vertical portion 3b2 of the shoulder portion 3b is provided with shoulder recesses 3b3 at four locations in the circumferential direction. The shoulder recesses 3b3 are recessed radially inward and have a roughly rectangular shape extending in the circumferential direction. By providing the shoulder recesses 3b3 on the shoulder portion 3b in this way, buckling extending vertically in the shoulder portion 3b can be effectively suppressed. Furthermore, when a lid (cap) (not shown) is attached to the opening 2, the lower end of the lid can be inserted into these shoulder recesses 3b3, thereby engaging and fixing the lid to the stacking container 1. Alternatively, the vertical portion 3b2 may not be provided on the shoulder portion 3b, and the lower end of the inclined portion 3b1 may be directly connected to the upper end of the body portion 3.

[0022] The body portion 3 of the stacked container 1 has a double-layer structure (stacked structure) comprising an inner layer 4 that partitions and forms a content storage space M, and an outer layer 5 that is stacked in close contact with the radially outer side of the inner layer 4, as shown in a partial cross-section in Figure 1. In this embodiment, the mouth portion 2 is composed only of the inner layer 4, and the shoulder portion 3b and body portion 3 have a configuration with both the inner layer 4 and the outer layer 5. However, the embodiment is not limited to this, and the mouth portion 2 may be composed only of the outer layer 5, or the mouth portion 2 may also have a double-layer structure with both the inner layer 4 and the outer layer 5.

[0023] Here, the inner layer 4 is composed of a nylon blend material, which is a blend of amorphous nylon resin and crystalline nylon resin. This nylon blend material contains 40% to 60% by weight of crystalline nylon resin. The nylon blend material also contains more than 40% by weight and less than 60% by weight of amorphous nylon resin.

[0024] For the amorphous nylon resin constituting the inner layer 4, for example, M-Schemy Japan Co., Ltd.'s model name: GRIVORY G21 ("GRIVORY" and "Grivory" are registered trademarks), which has excellent chemical resistance to nail polish, etc., can be used. However, it is not limited to this, and other amorphous nylon resins with excellent chemical resistance may also be used.

[0025] For the crystalline nylon resin constituting the inner layer 4, for example, model name LEXTER S8501 ("LEXTER" is a registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc. can be used. Crystalline nylon resins generally have excellent chemical resistance and a lower water content than amorphous nylon resins. However, the crystalline nylon resin is not limited to LEXTER S8501, and other crystalline nylon resins with excellent chemical resistance may be used. The inner layer 4 may also contain small amounts of other resins besides the nylon blend material.

[0026] The outer layer 5 is made of polyethylene terephthalate (PET) resin, which is a synthetic resin. The glass transition temperature (Tg) of the nylon blend material that makes up the inner layer 4 is higher than that of the synthetic resin that makes up the outer layer 5. The outer layer 5 may also contain small amounts of other resins besides PET resin.

[0027] Furthermore, the thickness (wall thickness) T4 of the inner layer 4 in the torso 3 is thinner than the thickness T5 of the outer layer 5. As shown in Figure 1, the thickness T4 of the inner layer 4 and the thickness T5 of the outer layer 5 were measured at a predetermined height (a predetermined position in the vertical direction) in the cylindrical portion 3a of the torso 3. Note that, for the torso 3 as a whole, it is sufficient that the thickness T4 of the inner layer 4 is thinner than the thickness T5 of the outer layer 5, and there may be parts, for example, in the shoulder portion 3b, where the thickness T4 of the inner layer 4 is locally thicker than the thickness T5 of the outer layer 5. Also, the thickness T4 of the inner layer 4 and the thickness T5 of the outer layer 5 do not need to be constant throughout the torso 3, and in this example, they are thicker than the cylindrical portion 3a at the bottom portion 3c. However, it is preferable that the thickness T4 of the inner layer 4 and the thickness T5 of the outer layer 5 are constant in the cylindrical portion 3a of the torso 3.

[0028] In Figure 1, the area enclosed by the dashed line labeled P is the printing area P. For example, when blow molding the laminated container 1 (blow molding process S4 in Figure 3), the label may be placed in the cavity of the blow molding die beforehand so that the in-mold label is integrally formed in the printing area P of the body 3 during blow molding.

[0029] The stacked container 1 according to this embodiment, shown in Figure 1, may have, for example, a total height of 48 mm, an outer diameter of the cylindrical portion 3a of the body 3 of 25 mm square, a height of 31.2 mm for the cylindrical portion 3a, an outer diameter of the mouth portion 2 (excluding the male thread portion 2b) of Φ12 mm, an inner diameter of the mouth portion 2 of 6.9 mm, and a capacity of 10 ml. However, it is not limited to this embodiment.

[0030] In this embodiment, the inner layer 4 is composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, and the outer layer 5 is composed of PET resin. In this case, the laminated container 1 can be used as a container for contents such as nail polish, which mainly consists of at least one of ethyl acetate, butyl acetate, toluene, and nitrocellulose, and has an alcohol content of 15% by weight or less. The nylon blend material constituting the inner layer 4 has chemical resistance and is suitable for the contents described above.

[0031] Furthermore, when the laminated container 1 is used as a container for nail polish, nail polish remover is often used near the laminated container 1 when removing the nail polish from the nails, so there is a risk that the nail polish remover may adhere to the outer surface of the laminated container 1. In this embodiment, the PET resin that makes up the outer layer 5 has resistance to acetone, which is the main component of nail polish remover, and alcohol, so there is no problem even if nail polish remover adheres to it. Therefore, the laminated container 1 of this embodiment is suitable for storing contents such as nail polish.

[0032] Furthermore, since the PET resin that makes up the outer layer 5 is less expensive than the nylon blend material that makes up the inner layer 4, the material cost can be reduced compared to constructing the entire laminated container 1 from nylon blend material. In addition, by forming the outer layer 5 made of PET resin with a thicker wall, a glass-like container can be created.

[0033] The stacked container 1 becomes a stacked container with contents by filling the contents into the storage space M. The stacked container with contents may, for example, have a lid (cap) equipped with a brush-like applicator that can be attached to the mouth 2, or it may simply have a lid that closes the upper end opening 2a of the mouth 2.

[0034] The manufacturing method for the laminated container 1 is described below. As shown in Figure 3, the manufacturing method for the laminated container 1 includes a primary preform molding step S1, a secondary preform molding step S2, a preheating step S3, and a blow molding step S4.

[0035] The primary preform molding process S1 is a process of molding the primary preform 10 shown in Figure 4 by injection molding using a first resin corresponding to the inner layer 4 of the laminated container 1. In Figure 4 and Figure 5, which will be described later, the shapes of the shoulder portion 3b, cylindrical portion 3a, and bottom portion 3c of the laminated container 1 after blow molding are shown by dashed lines. The primary preform 10 comprises a cylindrical mouth portion 12 and a bottomed cylindrical body portion 13 connected below the mouth portion 12. The primary preform 10 can be formed into various shapes to match the shape of the resin container after manufacturing, such as a bottomed cylindrical (approximately test tube-shaped) or a bottomed rectangular tubular. The mouth portion 12 is the part corresponding to the mouth portion 2 of the laminated container 1, and in this state of the primary preform 10, it is formed to be approximately the same shape as the mouth portion 2 of the laminated container 1 shown in Figure 1.

[0036] The primary preform molding process S1 and the secondary preform molding process S2 can be carried out, for example, using an injection molding machine equipped with a split mold. In this case, the first resin or the second resin can be automatically supplied into the closed split mold by a conveyor using a screw or the like.

[0037] The secondary preform molding process S2 is a process in which a secondary preform 20, which is formed by coating the outer surface of the main body portion 13 of the primary preform 10 with a second resin, is molded by injection molding. As shown in Figure 5, the secondary preform 20 comprises a mouth portion 22, which is the mouth portion 12 of the primary preform 10, and a bottomed cylindrical main body portion 23 that is connected below the mouth portion 22. The main body portion 23 corresponds to the body portion 3 of the laminated container 1 and is composed of a first resin layer 24 made of the first resin (the portion corresponding to the main body portion 13 of the primary preform 10) and a second resin layer 25 made of the second resin that is laminated in close contact with the outer surface of the first resin layer 24. In the secondary preform molding process S2, the secondary preform 20 can be molded by injection molding using the second resin while the primary preform 10 is placed in the mold as an insert material, for example, as in insert molding.

[0038] The preheating step S3 is a step of heating the secondary preform 20 to a temperature at which it can be blow molded (preheating temperature). Note that the "temperature at which the secondary preform 20 can be blow molded (preheating temperature)" refers to the temperature at which the stretching effect occurs in the secondary preform 20, in which the second resin layer 25 is laminated on the outside of the first resin layer 24, and blow molding becomes possible. This is different from the moldable temperature of the first resin alone and the moldable temperature of the second resin alone, which will be described later. The preheating step S3 can be carried out using, for example, a heating furnace, but is not limited to this, and various heating means can be used as long as the secondary preform 20 can be heated to a predetermined temperature.

[0039] The blow molding process S4 is a process in which the laminated container 1 is formed by blow molding using the secondary preform 20 heated in the preheating process S3. In the blow molding process S4, the secondary preform 20, which is set in the mold of the blow molding apparatus, is expanded and deformed by injecting a pressurizing medium supplied from a blow nozzle into the interior of the secondary preform 20, thereby forming it into a shape that conforms to the cavity of the mold. The pressurizing medium (pressurizing fluid) may be a gas or a liquid. The blow molding apparatus performing the blow molding process S4 may also be equipped with a stretching rod, in which case the preform may be stretched in the longitudinal direction (along the central axis O) by the stretching rod and stretched in the lateral direction by the pressurizing medium. The configuration of the blow molding apparatus used in the blow molding process S4 is not particularly limited.

[0040] Here, the moldable temperature of the first resin alone can be higher than the moldable temperature of the second resin alone. Also, the preheating temperature in the preheating step S3 can be higher than or equal to the moldable temperature of the second resin alone, and lower than or equal to the moldable temperature of the first resin alone. The "moldable temperature of the first resin alone" is the temperature at which, when only the first resin layer 24 made of the first resin is heated, a stretching effect occurs in the first resin layer 24, making it possible to blow mold it. Similarly, the "moldable temperature of the second resin alone" is the temperature at which, when only the second resin layer 25 made of the second resin is heated, a stretching effect occurs in the second resin layer 25, making it possible to blow mold it.

[0041] In this embodiment, the first resin can be a nylon blend material that constitutes the inner layer 4 of the laminated container 1. The second resin can be a PET resin that constitutes the outer layer 5 of the laminated container 1.

[0042] In the secondary preform 20, it is preferable that the thickness T24 of the first resin layer 24 constituting the main body 23 is thinner than the thickness T25 of the second resin layer 25. This makes it easier for the thickness T4 of the inner layer 4 in the laminated container 1 after the blow molding process S4 to be formed thinner than the thickness T5 of the outer layer 5. Furthermore, it is more preferable that the thickness T24 of the first resin layer 24 is 30% to 80% of the thickness T25 of the second resin layer 25, which improves moldability.

[0043] As explained above, the laminated container 1 of this embodiment is made of resin instead of glass, making it less likely to break even when subjected to impact such as dropping, and it is also lighter than a glass container, making it easier to handle.

[0044] Therefore, the laminated container 1 of this embodiment is lightweight, resistant to breakage, and can be used for contents such as nail polish.

[0045] As described above, this embodiment is a resin laminated container 1 comprising a cylindrical mouth portion 2 and a bottomed cylindrical body portion 3 provided below the mouth portion 2. The body portion 3 has an inner layer 4 that partitions and forms a storage space M for contents, and an outer layer 5 provided on the outer surface side of the inner layer 4. The inner layer 4 is composed of a nylon blend material that is a blend of amorphous nylon resin and crystalline nylon resin, and the nylon blend material is configured to contain 40% to 60% by weight of crystalline nylon resin. By adopting this configuration, the inner layer 4 contains amorphous nylon resin, which improves the chemical resistance of the inner layer 4 to nail polish and the like. In addition, by containing 40% or more by weight of crystalline nylon resin in the inner layer 4, the water content of the inner layer 4 can be suppressed, thereby improving chemical resistance and effectively suppressing crazing, which occurs when nail polish and the other contents penetrate into stress concentration areas and cause fine cracks. Furthermore, by limiting the proportion of crystalline nylon resin in the inner layer 4 to 60% by weight or less, whitening of the inner layer 4 can be suppressed even in high-temperature environments, and the transparency of the inner layer 4 can be maintained.

[0046] Furthermore, in this embodiment, the outer layer 5 is constructed of PET resin. By adopting this configuration, the material cost can be reduced compared to the case where the entire laminated container 1 is made of nylon resin, as PET resin, which is cheaper than nylon resin, is used for the outer layer 5. In addition, since the PET resin that makes up the outer layer 5 is resistant to acetone, which is the main component of nail polish remover, and alcohol, there is no problem even if nail polish remover adheres to it. Therefore, the laminated container 1 of this embodiment is suitable for storing contents such as nail polish.

[0047] Furthermore, in this embodiment, the thickness T4 of the inner layer 4 is configured to be thinner than the thickness T5 of the outer layer 5. By adopting this configuration, the proportion of nylon resin, which is generally more expensive than PET resin, can be reduced, so the laminated container 1 can be manufactured at a low cost. In addition, by configuring the glass transition temperature of the inner layer 4 to be higher than that of the outer layer 5, and the thickness T4 of the inner layer 4 to be thinner than the thickness T5 of the outer layer 5, the preheating temperature when blow molding using the secondary preform 20 in the manufacturing process of the laminated container 1 can be reduced. Furthermore, when blow molding the secondary preform 20 to form the laminated container 1, a difference in ease of stretching occurs, making the inner layer 4 more difficult to stretch. As a result, the bottom 3c of the laminated container 1 becomes thicker, and it can be molded into a shape that has a high-quality feel.

[0048] Furthermore, this embodiment is a laminated container with contents, comprising a laminated container 1 and contents contained in the storage space M of the laminated container 1, wherein the contents are mainly composed of at least one of ethyl acetate, butyl acetate, toluene, and nitrocellulose, and the alcohol component is 15% by weight or less. By adopting this configuration, the nylon blend material used in the inner layer 4 of the laminated container 1 of this embodiment has sufficient resistance to the contents, and thus it is possible to effectively suppress crazing, in which the contents penetrate into stress concentration areas and cause fine cracks.

[0049] Furthermore, this embodiment includes a primary preform molding step S1 in which a primary preform 10 having a mouth portion (mouth cylinder portion 12) and a main body portion 13 is molded by injection molding using a first resin; a secondary preform molding step S2 in which a secondary preform 20 having the outer surface of the main body portion 13 of the primary preform 10 coated with a second resin is molded by injection molding; a preheating step S3 in which the secondary preform 20 is heated to a preheating temperature that allows for blow molding; and blow molding using the secondary preform 20 heated in the preheating step S3. - The process includes a blow molding step S4 for forming a laminated container 1 by molding, wherein the moldable temperature of the first resin alone is higher than the moldable temperature of the second resin alone, and the preheating temperature is above the moldable temperature of the second resin alone and below the moldable temperature of the first resin alone, and the first resin is composed of a nylon blend material which is a blend of amorphous nylon resin and crystalline nylon resin, and the nylon blend material is configured to contain 40% to 60% by weight of crystalline nylon resin. By adopting such a configuration, the inner layer 4 contains amorphous nylon resin, so the chemical resistance of the inner layer 4 to nail polish, etc. can be improved. In addition, by containing 40% or more by weight of crystalline nylon resin in the inner layer 4, the water content of the inner layer 4 can be suppressed, thereby improving chemical resistance and effectively suppressing crazing, in which nail polish, etc., penetrates into stress concentration areas and causes fine cracks. Furthermore, by limiting the proportion of crystalline nylon resin in the inner layer 4 to 60% by weight or less, whitening of the inner layer 4 can be suppressed even in high-temperature environments, and the transparency of the inner layer 4 can be maintained.

[0050] Furthermore, in this embodiment, the second resin is configured to be made of PET resin. By adopting this configuration, the material cost can be reduced compared to the case where the entire secondary preform 20 is formed from nylon resin, as PET resin, which is cheaper than nylon resin, is used for the second resin. In addition, since the PET resin that makes up the second resin has resistance to acetone, which is the main component of nail polish remover, and alcohol, there is no problem even if nail polish remover adheres to it. Therefore, the laminated container 1 formed from the secondary preform 20 of this embodiment is suitable for storing contents such as nail polish.

[0051] Furthermore, in this embodiment, the secondary preform 20 is configured such that the thickness T24 of the first resin layer 24, which constitutes the main body portion 23, is thinner than the thickness T25 of the second resin layer 25, which constitutes the second resin. By adopting this configuration, the proportion of nylon resin, which is generally more expensive than PET resin, can be reduced, so that the laminated container 1 can be manufactured at a low cost. In addition, by configuring the glass transition temperature of the first resin layer 24 to be higher than that of the second resin layer 25, and the thickness T24 of the first resin layer 24 to be thinner than the thickness T25 of the second resin layer 25, the preheating temperature when blow molding using the secondary preform 20 in the manufacturing process of the laminated container 1 can be reduced. Furthermore, when blow molding the secondary preform 20 to form the laminated container 1, a difference in ease of stretching occurs, making the first resin layer 24 more difficult to stretch. As a result, the bottom portion 3c of the laminated container 1 becomes thicker, and it is possible to mold it into a shape that has a high-quality feel.

[0052] 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.

[0053] For example, in this embodiment, the opening 2 is provided with a male threaded portion 2b so that a cap having a female threaded portion can be attached. However, instead of the male threaded portion 2b, a recess or protrusion that engages with a protrusion or recess provided on the cap to fit and hold the cap may be provided. Also, although the opening 2 in this embodiment is formed in a cylindrical shape with a circular cross-section perpendicular to the central axis O, it is not limited to this, and may be a cylindrical shape with an elliptical or polygonal cross-section, for example.

[0054] Furthermore, in this embodiment, the inner layer 4 is configured to be composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, but it is sufficient for the nylon blend material to be the main component, and the inner layer 4 may contain small amounts of other materials, such as adhesive resin.

[0055] Furthermore, although the outer layer 5 is configured to be made of PET resin in this embodiment, it is sufficient that PET resin is the main component, and the outer layer 5 may also contain other resins such as adhesive resins. In addition, the outer layer 5 may also contain other resins such as polypropylene (PP) resin as the main component. [Examples]

[0056] To confirm the effects of the laminated container 1 of this disclosure, the moldability and chemical resistance of the laminated containers were evaluated for Examples 1 to 3, which have the layer configuration of this disclosure, as shown in Table 1, and Comparative Examples 1 to 4, which were prepared as comparative examples.

[0057] [Table 1]

[0058] In Table 1, the evaluation of "moldability" was based on visual inspection to determine whether whitening occurred in the inner layer and whether transparency was ensured. Products that could be commercialized were rated "Good," and those that could not be commercialized were rated "Poor." Alternatively, transparency may be determined by visible light transmittance, etc.

[0059] Furthermore, in Table 1, the evaluation of "chemical resistance" was performed using a mixture of butyl acetate and isopropyl alcohol (IPA) at a concentration of 10% by weight or less as the contents. The contents were applied to the opening, a lid was attached to the opening, and after 12 hours, the lid was opened and the condition of the opening was checked. If no crazing occurred at the opening, it was judged as "good," and if crazing occurred at the opening, it was judged as "bad."

[0060] In the evaluation of "moldability," when the proportion of crystalline nylon in the inner layer was 60% by weight or less (Examples 1 to 3, Comparative Examples 1 to 2), it was visually confirmed that no whitening due to crystallization of the inner layer occurred and transparency was ensured, resulting in a "good" rating.

[0061] On the other hand, when the proportion of crystalline nylon was 70% by weight or more (Comparative Examples 3 and 4), whitening occurred due to crystallization of the inner layer, resulting in a "negative" rating. From these evaluation results for "moldability," it was found that when the proportion of crystalline nylon in the inner layer is 60% by weight or less, whitening due to crystallization of the inner layer does not occur, and transparency can be ensured.

[0062] Furthermore, in the evaluation of "chemical resistance," when the proportion of crystalline nylon in the inner layer was 40% by weight or more (Examples 1 to 3), even after 12 hours had passed since applying the contents to the opening and attaching the lid, the moisture content of the inner layer remained below 1.8% by weight, and no crazing occurred at the opening, resulting in a "good" rating. In addition, in Examples 1 to 3, even when the test was extended beyond 12 hours and continued until the moisture content of the inner layer reached 3.0% by weight, no crazing occurred at the opening.

[0063] On the other hand, when the proportion of crystalline nylon in the inner layer was less than 40% by weight (Comparative Examples 1 and 2), crazing occurred in the inner layer when the moisture content reached 2.2-2.4% by weight before 12 hours had elapsed since attaching the lid to the opening, resulting in a "negative" evaluation. Note that for Comparative Examples 3 and 4, the "formability" evaluation was "negative," so the "chemical resistance" evaluation was not performed. From the results of this "chemical resistance" evaluation, it was found that if the proportion of crystalline nylon in the inner layer is 40% by weight or more, crazing does not occur in the inner layer even after the test. Furthermore, when the inner layer is made of a nylon blend material of amorphous nylon and crystalline nylon, the water absorption rate decreases because the water absorption rate of crystalline nylon is lower than that of amorphous nylon. Specifically, when the same amount of time elapsed as when the moisture content rose to 2.4% by weight when the inner layer was made of amorphous nylon, the moisture content when the inner layer was made of a nylon blend material was 1.8% by weight. In other words, it was found that by using a nylon blend material for the inner layer, it is possible to slow down the increase in the moisture content of the inner layer during storage. [Explanation of symbols]

[0064] 1: Laminated container 2: Mouth 2a: Top opening 2b: Male threaded section 2c: Neck ring 3: Torso 3a: Cylinder part 3b: Shoulder 3b1: Inclined part 3b2: Vertical section 3b3:Shoulder recess 3b4: Stepped section 3c: Bottom 4: Inner layer 5: Outer layer 10:1 primary preform 12: Mouth part (mouth part) 13: Main body 20:2nd Preform 22: Mouth part (mouth part) 23: Main body 24: 1st resin layer 25: Second resin layer M: Containment space O: Central axis P:Print area S1: Primary preform molding process S2: Secondary preform molding process S3: Preheating process S4: Blow molding process T4: Inner layer thickness T5: Outer layer thickness T24: Thickness of the first resin layer T25: Thickness of the second resin layer

Claims

1. A resin laminated container comprising a cylindrical opening and a bottomed cylindrical body provided below the opening, The body portion has an inner layer that partitions and forms a space for containing the contents, and an outer layer provided on the outer surface side of the inner layer. The inner layer is composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, and the nylon blend material contains 40% to 60% by weight of crystalline nylon resin, in a laminated container.

2. The laminated container according to claim 1, wherein the outer layer is made of PET resin.

3. The laminated container according to claim 1 or 2, wherein the thickness of the inner layer is thinner than the thickness of the outer layer.

4. A laminated container containing contents, comprising a laminated container according to claim 1 or 2 and contents contained in the storage space of the laminated container, A laminated container containing contents, wherein the contents mainly consist of at least one of ethyl acetate, butyl acetate, toluene, and nitrocellulose, and the alcohol content is 15% by weight or less.

5. A primary preform molding step in which a primary preform having a mouth portion and a main body portion is molded by injection molding using a first resin, A secondary preform molding step is performed in which a secondary preform is formed by injection molding in which the outer surface of the main body of the primary preform is coated with a second resin, A preheating step of heating the secondary preform to a preheating temperature that allows for blow molding, The process includes a blow molding step in which a laminated container is formed by blow molding using the secondary preform heated in the preheating step, The moldable temperature of the first resin alone is higher than the moldable temperature of the second resin alone, and the preheating temperature is equal to or greater than the moldable temperature of the second resin alone, and equal to or less than the moldable temperature of the first resin alone. A method for manufacturing a laminated container, wherein the first resin is composed of a nylon blend material obtained by blending amorphous nylon resin and crystalline nylon resin, and the nylon blend material contains 40% by weight or more and 60% by weight or less of crystalline nylon resin.

6. The method for manufacturing a laminated container according to claim 5, wherein the second resin is made of PET resin.

7. The method for manufacturing a laminated container according to claim 5 or 6, wherein the thickness of the first resin layer, which constitutes the main body of the secondary preform, is thinner than the thickness of the second resin layer, which constitutes the second resin.

Images