Synthetic resin container, preform, synthetic resin container manufacturing method, and container body

Abstract

To provide a synthetic resin-made container, a preform, a method for manufacturing a synthetic resin-made container, and a container body which improve recyclability.SOLUTION: A synthetic resin-made container 1 includes a container body 10 having an outer layer body 2, and an inner layer body 3 separably stacked on the inner surface of the outer layer body 2, and a mounting cap 20 mounted on the container body 10, wherein the container body 10 includes a cylindrical mouth part 4 on which the mounting cap 20 is mounted, a body part 5 which is positioned below the mouth part 4 and forms a storage space S of a content, and a bottom part 9 for blocking the lower end of the body part 5, the upper end of the outer layer body 2 is positioned below the upper end of the inner layer body 3, and the outer layer body 2 has a slit 6 extending downward from the upper end.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a synthetic resin container having an outer layer and an inner layer detachably laminated on the inner surface of the outer layer, a preform, a method for manufacturing a synthetic resin container, and a container body. [Background technology]

[0002] BACKGROUND ART Laminated containers have been known for some time as containers for storing liquid contents such as food seasonings such as soy sauce, beverages, cosmetics such as lotions, and toiletries such as shampoos, conditioners, and liquid soaps (see, for example, Patent Document 1).

[0003] Such a laminated container has a double structure in which an inner layer having a storage space for the liquid contents is laminated on the inner surface of an outer layer which has a cylindrical mouth, a body connected to the mouth, and a bottom which closes the lower end of the body and forms the outer shell of the container.

[0004] The laminated container can be produced by, for example, stretch-blow molding a double preform that combines an inner preform that constitutes an inner layer body and an outer preform that constitutes an outer layer body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-121540 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-mentioned laminated container, if the contents contained in the inner layer contain oil components, the container with the contents attached thereto becomes difficult to recycle in its current state, and there is room for improvement in this regard.

[0007] The present disclosure has been made in consideration of such problems, and its purpose is to provide a synthetic resin container, a preform, a method for manufacturing a synthetic resin container, and a container body that have improved recyclability. [Means for solving the problem]

[0008] In order to solve the above problems, the synthetic resin container of the present disclosure comprises: [1] a container body having an outer layer and an inner layer detachably laminated on the inner surface of the outer layer; an attachment cap attached to the container body; A synthetic resin container comprising: The container body is a cylindrical opening portion to which the attachment cap is attached; a body portion located below the mouth portion and forming a storage space for contents; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer layer body is located lower than the upper end of the inner layer body, The outer layer has a slit extending downward from the upper end. death, The mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner layer body and an outer wall of the mouth portion provided at the upper end of the outer layer body. It is characterized by:

[0009] Further, the synthetic resin container of the present disclosure is [2] In the above configuration [1], it is preferable that a plurality of the slits are provided in the circumferential direction.

[0010] Further, the synthetic resin container of the present disclosure is [3] In the configurations [1] or [2] above, it is preferable that the mouth portion of the inner layer body and the attachment cap have a first engagement portion that secures them together by engagement, and the upper end portion of the outer layer body and the attachment cap have a second engagement portion that secures them together by engagement.

[0011] Further, the synthetic resin container of the present disclosure is [4] In the configuration [3] above, it is preferable that a detachable piece that can be separated by a weakened portion is provided at the lower part of the attachment cap, and the second engagement portion on the attachment cap side is provided on the detachable piece.

[0012] Further, the synthetic resin container of the present disclosure is [5] In any of the above configurations [1] to [4], it is preferable that the container body further comprises a shoulder portion whose diameter expands downward from the lower end of the mouth portion, and that the slit extends from the upper end of the outer layer body to at least a portion of the shoulder portion.

[0013] In order to solve the above problems, the preform of the present disclosure comprises: [6] A synthetic resin preform for use in stretch blow molding, comprising an outer body and an inner body laminated on the inner surface of the outer body, A cylindrical mouth portion, a body portion located below the mouth portion; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer body is located lower than the upper end of the inner body, The outer body has a slit extending downward from the upper end. death, The mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner body and an outer wall of the mouth portion provided at the upper end of the outer body. It is characterized by:

[0014] In order to solve the above problems, the method for manufacturing a synthetic resin container according to the present disclosure includes: [7] A method for manufacturing a synthetic resin container by stretch blow molding a preform, comprising: The preform has an outer body and an inner body laminated on the inner surface of the outer body, A cylindrical mouth portion, a body portion located below the mouth portion; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer body is located lower than the upper end of the inner body, The outer body has a slit extending downward from an upper end thereof, the mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner body and an outer wall of the mouth portion provided at the upper end of the outer body, molding the outer body and the inner body; fitting the inner body onto the inner circumferential surface of the outer body to form a preform; stretch blow molding the preform to form a container body; The present invention is characterized by comprising:

[0015] In order to solve the above problems, the container body of the present disclosure comprises: [8] A container body having an outer layer and an inner layer separably laminated on the inner surface of the outer layer, A cylindrical mouth portion, a shoulder portion whose diameter increases downward from the lower end of the mouth portion; a body portion that is connected to a lower portion of the shoulder portion and forms a storage space for contents; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer layer body is located lower than the upper end of the inner layer body, The outer layer has a slit extending downward from the upper end. death, The mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner layer body and an outer wall of the mouth portion provided at the upper end of the outer layer body. It is characterized by:

[0016] The container body of the present disclosure is [9] In the above configuration [8], it is preferable that the slit has a widened portion at the lower end thereof that widens in the circumferential direction.

[0017] The container body of the present disclosure is

[10] In the configuration [8] or [9] above, the lower end of the slit terminates at the shoulder portion, and the radial distance B from the central axis of the outer surface of the lower end of the slit and the radial distance A from the central axis of the outer surface of the lower end of the mouth portion are within 1.0 [Effects of the Invention] ​

[0018] According to the present disclosure, it is possible to provide a synthetic resin container, a preform, a method for manufacturing a synthetic resin container, and a container body with improved recyclability. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a front partial cross-sectional view of a synthetic resin container according to a first embodiment of the present disclosure. [Figure 2] 2 is a partially enlarged front cross-sectional view of the opening of the container body and the attached cap portion in FIG. 1. FIG. [Figure 3] 1 is a front view of a container body that constitutes a synthetic resin container according to a first embodiment of the present disclosure. [Figure 4] FIG. 2 is a partial front cross-sectional view showing a state in which the detachable piece of the attachment cap is separated from the state shown in FIG. 1 and preparations are being made to separate the attachment cap and the inner layer body. [Figure 5] 5 is a partial front cross-sectional view showing the state in which the attachment cap and the inner layer body are being pulled out from the outer layer body and separated from the state shown in FIG. 4.

[0023] FIG. [Figure 6] 1 is a front half cross-sectional view of a preform according to a first embodiment of the present disclosure. [Figure 7] 1 is a flowchart showing the steps of a method for manufacturing a synthetic resin container according to a first embodiment of the present disclosure. [Figure 8] FIG. 4 is a partial front cross-sectional view of a container body according to a second embodiment of the present disclosure. [Figure 9] 9 is a partially enlarged front cross-sectional view of the mouth and shoulder portion of the container body in FIG. 8. FIG. [Figure 10] FIG. 4 is a front half cross-sectional view of a preform according to a second embodiment of the present disclosure. [Figure 11] 11 is a cross-sectional view of the outer body taken along the line AA in FIG. 10. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present disclosure will now be described in more detail with reference to the drawings.

[0021] 1, a synthetic resin container 1 according to a first embodiment of the present disclosure includes a double-layered container body 10 having an outer layer 2 and an inner layer 3, and an attachment cap 20 that is attached to the mouth 4 of the container body 10. The outer shape of the container body 10 is bottle-shaped, having a cylindrical mouth 4, a shoulder 7 that is located below the mouth 4 and expands in diameter downward from the lower end of the mouth 4, a cylindrical body 5 that continues below the shoulder 7 and forms a storage space S for the contents, and a bottom 9 that closes the lower end of the body 5.

[0022] In this specification, claims, and drawings, the up-down direction means the upper and lower directions when the synthetic resin container 1 is in an upright position as shown in Fig. 1. Furthermore, the radially outward direction means the direction away from the central axis O1 along a straight line that passes through the central axis O1 of the synthetic resin container 1 in Fig. 1 and is perpendicular to the central axis O1, and the radially inward direction means the direction toward the central axis O1 along that straight line.

[0023] In this embodiment, the container body 10 comprises an outer layer 2 that forms the outer shell of the barrel 5, and an inner layer 3 that is separably laminated on the inner surface of the outer layer 2. As shown in Figure 2, the upper end of the outer layer 2 is located lower than the upper end of the inner layer 3, and the upper part of the mouth 4 is formed only by the inner layer 3.

[0024] As shown in Figure 2, the mouth portion 4 of the inner layer body 3 has a cylindrical mouth portion inner wall 4c, an annular protrusion 4a that protrudes radially outward from the upper part of the mouth portion inner wall 4c, and a locking flange 4b ​​that extends approximately horizontally radially outward below the annular protrusion 4a on the mouth portion inner wall 4c.

[0025] The inner layer body 3 can be formed into a bag-like shape thinner than the outer layer body 2 using a synthetic resin material such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyamide (nylon), or ethylene-vinyl alcohol copolymer (EVOH), and is separably laminated on the inner surface of the outer layer body 2. In this embodiment, the inner layer body 3 is formed from the same polyethylene terephthalate as the outer layer body 2. The inner layer body 3 may be thicker than the outer layer body 2. The interior of the inner layer body 3 forms a storage space S that communicates with the opening of the mouth portion 4. This storage space S can contain, for example, food seasonings such as cooking oil and soy sauce, beverages, cosmetics such as lotion, and toiletries such as shampoo, conditioner, and liquid soap. Separation of the inner layer body 3 from the inner surface of the outer layer body 2 may be separation from an adhered state, separation from a pseudo-adhered state in the case of incompatible resin laminates, or separation from a tightly adhered state.

[0026] On the other hand, the outer layer body 2 constituting the container body 10 includes a mouth outer wall 4d, an annular protrusion 4e protruding radially outward from the upper part of the mouth outer wall 4d, and a neck ring 8 extending substantially horizontally radially outward below the annular protrusion 4e, as shown in Fig. 2. Also, as shown in Fig. 2, the upper end of the mouth outer wall 4d abuts against and is locked to the lower surface of the locking flange 4b, thereby determining the vertical position of the outer layer body 2 relative to the inner layer body 3.

[0027] As shown in Fig. 3, the outer layer body 2 has a plurality of slits 6 extending downward from the upper end portion. The slits 6 extend from the annular protrusion 4e located at the upper end portion of the outer layer body 2 in the mouth portion 4, across the neck ring 8, to the lower portion of the shoulder portion 7. In this embodiment, the slits 6 are provided at eight equally spaced locations in the circumferential direction.

[0028] The number and length of the slits 6 can be changed in various ways. The slits 6 may extend beyond the shoulder 7 to a part of the body 5, or may terminate at the lower end of the shoulder 7. The slits 6 may also terminate partway through the shoulder 7. The slits 6 only need to extend beyond the lower end of the mouth 4 to a part of the shoulder 7. With this configuration, the slits 6 open in the circumferential direction, as described below, to expand the diameter of the upper end of the outer layer 2, making it easier to pull the inner layer 3 out of the outer layer 2. The slits 6 may also have a circumferentially expanded lower end, as in a second embodiment described below.

[0029] In this embodiment, a plurality of slits 6 are arranged in a line in the circumferential direction. With this configuration, the upper end of the outer layer body 2 is enlarged and expands in diameter evenly in the circumferential direction, making it easier to pull the inner layer body 3 out of the outer layer body 2.

[0030] When molding the container body 10 by stretch blow molding a preform 11 (see Figure 6) described below, for example, the neck ring 8 can be attached to the mold without tilting the preform 11 by abutting the lower surface of the neck ring 18 against the reference surface of the blow molding mold.

[0031] In this embodiment, the slit 6 is provided from the upper end of the outer layer body 2 to the shoulder portion 7, so that when the inner layer body 3 fitted with the attachment cap 20 is removed from the outer layer body 2 to the outside, the slit 6 opens in the circumferential direction, causing the shoulder portion 7 to deform in a direction that increases the inclination relative to the horizontal direction, thereby expanding the diameter of the upper end of the outer layer body 2. Therefore, the inner layer body 3 contained within the outer layer body 2 can be easily removed to the outside through the expanded upper end of the outer layer body 2.

[0032] In this embodiment, the slit 6 serves as an outside air introduction groove when the outer layer 2 and the inner layer 3 are separated. When the user has finished using the contents in the inner layer 3, in order to recycle the synthetic resin container 1, the user separates it by pulling the inner layer 3, with the attached cap 20 attached, upward from the outer layer 2, as shown in FIG. 5. At this time, outside air is introduced into the space between the outer layer 2 and the inner layer 3 through the slit 6, which functions as an outside air introduction groove, so that the inner layer 3 can be easily separated from the outer layer 2 and easily pulled out to the outside of the outer layer 2. Note that an outside introduction groove other than the slit 6 may be provided. For example, additional outside air introduction grooves may be provided in the body 5 or the bottom 9.

[0033] The outer layer 2 constitutes the outer shell of the container body 10 of this synthetic resin container 1, and can be made of a synthetic resin material such as polyethylene terephthalate (PET), polypropylene (PP), or polyethylene (PE). In this embodiment, the outer layer 2 is made of polyethylene terephthalate. The portion of the outer layer 2 corresponding to the body 5 is flexible and can be squeezed to become depressed, and can also return to its original shape from the depressed state.

[0034] As shown in Fig. 2, an attachment cap 20 is attached to the mouth portion 4 of the container body 10. In this embodiment, the attachment cap 20 includes a cap body 21 and a lid body 25 that covers a pouring hole (not shown) of the cap body 21 from above.

[0035] As shown in Figure 2, the cap body 21 comprises an outer peripheral wall 21a that surrounds the mouth portion 4 of the container body 10 from the radial outside, a top wall 22 that is continuous with the upper end of the outer peripheral wall 21a, a detachable piece 28 that is detachably provided at the lower end of the outer peripheral wall 21a by a weakened portion 28c, a sealing wall 23 that hangs down from the top wall 22 radially inside the outer peripheral wall 21a, an inner peripheral wall 24 that hangs down from the top wall 22 radially inside the sealing wall 23 and sandwiches the mouth inner wall 4c between itself and the sealing wall 23 to provide a liquid-tight seal, and a pouring hole that is provided in the top wall 22 radially inside the inner peripheral wall 24.

[0036] An engaging protrusion 23a is provided on the inside of the lower end of the sealing wall 23 to undercut-engage with an annular protrusion 4a provided on the mouth inner wall 4c to fix the attachment cap 20 to the inner layer body 3 of the container body 10. The annular protrusion 4a and the engaging protrusion 23a form a first engaging portion that fixes the mouth 4 (mouth inner wall 4c) of the inner layer body 3 and the attachment cap 20.

[0037] The detachment piece 28 is an annular portion provided via a weakened portion 28c at the lower end of the outer peripheral wall 21a of the cap body 21 of the attachment cap 20. The detachment piece 28 includes a peripheral wall 28a and a knob portion 28b provided integrally with the peripheral wall 28a on the radially outer side of the peripheral wall 28a.

[0038] The gripping portion 28b is a strip-shaped portion extending in the circumferential direction, and the user can grip the gripping portion 28b and pull it radially outward to tear off the weakened portion 28c and separate the peripheral wall 28a from the outer peripheral wall 21a of the cap body 21.

[0039] An engaging protrusion 28a1 is provided on the inside of the lower end of the peripheral wall 28a of the detachable piece 28 to undercut-engage with an annular protrusion 4e provided on the outer wall 4d of the mouth portion to fix the detachable piece 28 to the outer layer 2 of the container body 10. The annular protrusion 4e and the engaging protrusion 28a1 form a second engaging portion that fixes the upper end of the outer layer 2 and the detachable piece 28 of the attachment cap 20.

[0040] In this embodiment, the first and second engaging portions are configured as a pair of engaging portions that secure the members together by undercut engagement, but the present invention is not limited to this. For example, instead of the first engaging portion being configured to include the annular protrusion 4a and the engaging protrusion 23a, the first engaging portion may be configured such that a male threaded portion provided on the outer surface of the mouth portion inner wall 4c is threadedly engaged with a female threaded portion provided on the inner surface of the seal wall 23.

[0041] Furthermore, instead of providing the detachment piece 28, the second engagement portion may be formed by engaging the annular protrusion 4e of the mouth outer wall 4d with the outer peripheral wall 21a of the cap body 21. In this case, it is preferable that the second engagement portion be configured to be more easily disengaged than the first engagement portion.

[0042] The lid body 25 is integrally formed with the cap body 21 by a hinge portion (not shown). The lid body 25 includes a lid body peripheral wall 26 provided above the outer peripheral wall 21a with substantially the same diameter as the outer peripheral wall 21a, and a top wall 27 closing the upper end of the lid body peripheral wall 26.

[0043] An engaging protrusion 26a is provided on the inner surface of the lower portion of the lid peripheral wall 26. This engaging protrusion 26a is undercut-engaged with an annular protrusion 22a provided on a step 22b on the outer edge of the top wall 22 on the cap body 21 side, thereby enabling the lid 25 to be attached to the cap body 21. Note that instead of the engagement between the engaging protrusion 26a and the annular protrusion 22a, the lid 25 may be attached to the cap body 21 by screw engagement.

[0044] The synthetic resin container 1 having such a configuration can pour the contents from the storage space S to the outside by, for example, tilting it so that the opening 4 is positioned below the bottom 9. Furthermore, in the synthetic resin container 1 of this embodiment, a slit 6 is provided from the upper end of the outer layer 2 to the shoulder 7, making it easy to separate the inner layer 3 from the outer layer 2 in the vicinity of the area where this slit 6 is provided. Therefore, when the user has finished using the contents in the storage space S, the user can easily separate the inner layer 3 from the outer layer 2 using this slit 6 as a starting point and pull it out of the outer layer 2.

[0045] When the user has finished using the contents in the storage space S of the synthetic resin container 1 described above and wishes to recycle the container, the user grasps the tab 28b of the detachment piece 28 and pulls it radially outward, thereby tearing off the weakened portion 28c and detaching the peripheral wall 28a from the cap body 21 (see FIG. 4). This disengages the annular protrusion 4e of the outer layer body 2 from the engaging protrusion 28a1 of the detachment piece 28 of the attachment cap 20 (second engagement portion). Therefore, the user can hold the outer layer body 2 in one hand while holding the attachment cap 20 with the other hand and lift it upward, thereby pulling up the attachment cap 20 and the inner layer body 3 fixed to the attachment cap 20 by the first engagement portion (see FIG. 5).

[0046] When the inner layer body 3 is pulled upward from inside the outer layer body 2, the pulled inner layer body 3 presses against the outer layer body 2 at the shoulder portion 7 from the inside and spreads it radially outward, as shown in Figure 5, causing the slits 6 provided in the shoulder portion 7 to open in the circumferential direction and displacing the upper end of the outer layer body 2 radially outward. This radially outward deformation of the upper end of the outer layer body 2 expands the diameter of the opening, making it easier to remove the inner layer body 3 from the outside of the outer layer body 2 compared to the state shown in Figure 4.

[0047] The container body 10 constituting this synthetic resin container 1 can be formed by stretch blow molding a synthetic resin preform 11 according to the first embodiment of the present disclosure shown in FIG.

[0048] The preform 11 has a double structure including a synthetic resin outer body 12 that forms the outer layer body 2 and a synthetic resin inner body 13 that forms the inner layer body 3, and its outer shape is a bottomed tubular shape (approximately test tube shape) having a cylindrical mouth portion 14, a cylindrical body portion 15 that continues below the mouth portion 14, and a bottom portion 19 that closes the lower end of the body portion 15. The mouth portion 14 is formed in a shape that corresponds to the mouth portion 4 of the synthetic resin container 1. In other words, the mouth portion inner wall 14c, mouth portion outer wall 14d, annular protrusions 14a, 14e, locking flange 14b, and neck ring 18 of the preform 11 have approximately the same shapes as the mouth portion inner wall 4c, mouth portion outer wall 4d, annular protrusions 4a, 4e, locking flange 4b, and neck ring 8 of the synthetic resin container 1. That is, the portion of the preform 11 above the neck ring 18 is a non-stretched region that is hardly deformed by stretch blow molding, and has roughly the same shape as the mouth 4 of the synthetic resin container 1. The preform 11 has a tapered portion 17 that tapers from the neck ring 18 of the mouth 14 toward the body 15, and in the region of this tapered portion 17, the outer body 12 and the inner body 13 are radially spaced apart, as shown in FIG. 6. The bottom 19 is formed in a curved shape (hemispherical). Note that the symbol O2 indicates a central axis common to the mouth 14, body 15, and bottom 19.

[0049] A slit 16 is provided from the upper end of the outer body 12 to a part of the reduced diameter portion 17. In this embodiment, the part of the slit 16 below the neck ring 18 is an extended part, which constitutes part of the shoulder portion 7 after stretch blow molding. On the other hand, the part above the slit 16 (the neck ring 18 and above it) is a non-extended part, which generally maintains its original shape even after stretch blow molding.

[0050] The outer body 12 is formed of the same synthetic resin material as the outer layer body 2, namely, polyethylene terephthalate (PET). The inner body 13 is also formed of the same synthetic resin material as the inner layer body 3, polyethylene terephthalate (PET). The inner body 13 is formed thinner than the outer body 12 and is laminated on the inner surface of the outer body 12 with gaps so as to cover the entire inner surface. This laminated state may be configured so that the inner body 13 is in close contact with the entire surface or in partial contact. The inner body 13 may be configured to be thicker than the outer body 12. Furthermore, the inner body 13 (inner layer body 3) may be made of a different synthetic resin from the outer body 12 (outer layer body 2) to facilitate separation from the outer body 12. For example, if the outer body 12 is made of PET and the inner body 13 is made of PP, separation will be easier. Furthermore, the inner body 13 may be a single-layer structure formed of only a single synthetic resin, or may be made of multiple synthetic resins to improve barrier properties and content resistance.

[0051] Next, a method for manufacturing the synthetic resin container 1 according to the first embodiment of the present disclosure will be described.

[0052] FIG. 7 is a flowchart showing the procedure for carrying out the method for manufacturing the synthetic resin container 1 according to this embodiment.

[0053] First, a method for forming a preform 11 for manufacturing a container body 10 by stretch blow molding will be described. First, an outer body 12 having a slit 16 at its upper end, as shown in FIG. 6, is molded by injection molding (step S101). In parallel with molding of the outer body 12, an inner body 13 is molded by a separate injection molding process (step S102). Note that although FIG. 7 shows that the inner body 13 is molded following molding of the outer body 12, the order of molding does not matter, as the molding of both bodies can be performed independently. Furthermore, molding of the outer body 12 and inner body 13 is not limited to injection molding, and other molding methods such as compression molding may also be used.

[0054] Next, the outer peripheral surface of the inner body 13 formed in step S102 is fitted onto the inner peripheral surface of the outer body 12, thereby forming the preform 11 (step S103). When forming this preform 11, as shown in Fig. 6, the upper end of the mouth outer wall 14d of the outer body 12 abuts against the lower surface of an annular locking flange 14b that protrudes radially outward from the mouth inner wall 14c at the mouth 14 of the inner body 13, thereby positioning the inner body 13 in the up-down direction relative to the outer body 12. Alternatively, for example, a convex portion formed on a portion of the circumferential direction on the outer peripheral surface of the inner body 13 may be fitted into a concave portion formed on a portion of the circumferential direction on the inner peripheral surface of the outer body 12, thereby aligning the circumferential positions of the two.

[0055] Next, the preform 11 formed in step S103 is stretch-blow molded to produce the container body 10, which is a laminated container (step S104). In this stretch-blow molding, first, the stretched portion of the preform 11 is heated in a heating furnace. At this time, the mouth portion 14, which is the non-stretched portion, may be covered with a heat insulating material or the like. Next, while the preform 11 is in a heated state, the neck ring 18 of the preform 11 is abutted against a reference surface of a blow-molding mold and fixed, and stretch-blow molding is performed. The outer body 12 and inner body 13 are stretched downward by the stretch rod and blow-molded radially outward by high-pressure air.

[0056] In this embodiment, the mouth portion 4 and the body portion 5 are formed in a substantially cylindrical shape, but are not limited to this and can also be formed in a rectangular or elliptical cylindrical shape, for example. Similarly, in the preform 11 of this embodiment, the mouth portion 14 and the body portion 15 are formed in a substantially cylindrical shape, but are not limited to this and can also be formed in a rectangular or elliptical cylindrical shape, for example.

[0057] Next, after filling the inner layer 3 of the container body 10 formed in step S104 with the contents, the attachment cap 20, which has been formed in a separate process by injection molding or the like, is fixed to the inner layer 3 of the container body 10 (step S105 in FIG. 7). To fix the attachment cap 20, an annular protrusion 4a (one of the first engaging portions) provided at the upper end of the mouth inner wall 4c of the container body 10 is undercut-engaged with an engagement protrusion 23a (the other of the first engaging portions) provided on the seal wall 23 of the attachment cap 20. At this time, an annular protrusion 4e (one of the second engaging portions) provided at the upper end of the mouth outer wall 4d of the container body 10 also undercut-engages with an engagement protrusion 28a1 (the other of the second engaging portions) provided at the lower end of the peripheral wall 28a of the detachment piece 28 of the attachment cap 20. Execution of step S105 completes the production of the synthetic resin container 1.

[0058] As described above, the synthetic resin container 1 according to this embodiment comprises a container body 10 having an outer layer 2 and an inner layer 3 detachably laminated on the inner surface of the outer layer 2, and an attachment cap 20 attached to the container body 10. The container body 10 comprises a cylindrical mouth 4 to which the attachment cap 20 is attached, a body 5 located below the mouth 4 and forming a storage space S for the contents, and a bottom 9 closing the lower end of the body 5. The upper end of the outer layer 2 is located below the upper end of the inner layer 3, and the outer layer 2 has a slit 6 extending downward from the upper end. By adopting this configuration, when the inner layer 3 with the attachment cap 20 attached is removed from the outer layer 2 to the outside, the slit 6 opens circumferentially, allowing the upper end of the outer layer 2 to expand in diameter. Therefore, the inner layer 3 contained within the outer layer 2 can be easily removed to the outside through the expanded upper end of the outer layer 2. The inner layer body 3 and attached cap 20 with the contents attached thereto can be easily separated from the outer layer body 2 with no contents attached thereto, allowing the synthetic resin container 1 to be recycled. In addition, since the slit 6 serves as an outside air introduction groove, when the inner layer body 3 is separated from the outer layer body 2, air is introduced between the outer layer body 2 and the inner layer body 3 through the slit 6, and the inner layer body 3 can be easily separated from the outer layer body 2 using the slit 6 as a starting point.

[0059] Furthermore, in the synthetic resin container 1 according to this embodiment, the slits 6 are configured to be provided in multiple locations in the circumferential direction. By adopting this configuration, when the inner layer body 3 fitted with the attachment cap 20 is removed from the outer layer body 2 to the outside, the slits 6 open widely and evenly in the circumferential direction, allowing the diameter of the upper end of the outer layer body 2 to be expanded. Therefore, the inner layer body 3 contained within the outer layer body 2 can be more easily removed to the outside through the upper end of the outer layer body 2, which has a large and evenly expanded diameter in the circumferential direction.

[0060] Furthermore, in the synthetic resin container 1 according to this embodiment, the mouth 4 of the inner layer 3 and the attachment cap 20 have a first engagement portion that secures them together by engagement, and the upper end of the outer layer 2 and the attachment cap 20 have a second engagement portion that secures them together by engagement. By adopting this configuration, the inner layer 3 with the attachment cap 20 attached can be pulled upward from the outer layer 2 by releasing the engagement between the upper end of the outer layer 2 and the attachment cap 20 at the second engagement portion, and the slits 6 open circumferentially, expanding the diameter of the upper end of the outer layer 2, making it possible to easily remove the inner layer 3 from the outside.

[0061] Furthermore, in the synthetic resin container 1 according to this embodiment, the lower part of the attached cap 20 is provided with a detachable piece 28 that can be separated by a weakened portion 28c, and the second engagement portion on the attached cap 20 side is configured to be provided on the detachable piece 28. With this configuration, when a user has finished using the contents and is sorting the container, they can tear off the weakened portion 28c to detach the detachable piece 28 from the attached cap 20, automatically releasing the engagement between the upper end of the outer layer body 2 and the attached cap 20 at the second engagement portion. This allows the user to easily pull the inner layer body 3 with the attached cap 20 attached upward from the outer layer body 2 and remove it from the outside.

[0062] Furthermore, in the synthetic resin container 1 according to this embodiment, the container body 10 further includes a shoulder 7 whose diameter expands downward from the lower end of the mouth 4, and the slit 6 is configured to extend from the upper end of the outer layer 2 to at least a portion of the shoulder 7. By adopting this configuration, when the inner layer 3 fitted with the attachment cap 20 is removed from the outer layer 2 to the outside, the slit 6 opens circumferentially, causing the shoulder 7 to deform in a direction that increases the inclination relative to the horizontal direction, effectively expanding the diameter of the upper end of the outer layer 2. Therefore, the inner layer 3 contained within the outer layer 2 can be easily removed to the outside through the upper end of the outer layer 2, which has expanded in diameter up to the shoulder 7.

[0063] Furthermore, the preform 11 according to this embodiment is a synthetic resin preform 11 for use in stretch blow molding, having an outer body 12 and an inner body 13 laminated on the inner surface of the outer body 12, and including a tubular mouth 14, a body 15 located below the mouth 14, and a bottom 19 closing the lower end of the body 15. The upper end of the outer body 12 is located lower than the upper end of the inner body 13, and the outer body 12 has a slit 16 extending downward from the upper end. By adopting this configuration, in a synthetic resin container 1 in which an attachment cap 20 is attached to the inner layer body 3 of a container body 10 obtained by stretch blow molding the preform 11 having the above configuration, when the inner layer body 3 with the attachment cap 20 attached is removed from the outer layer body 2 to the outside, the slit 6 formed by blow molding the slit 16 opens circumferentially, allowing the upper end of the outer layer body 2 to expand in diameter. Therefore, the inner layer body 3 contained in the outer layer body 2 can be easily removed to the outside through the expanded upper end of the outer layer body 2. The inner layer body 3 and attached cap 20 with the contents attached thereto can be easily separated from the outer layer body 2 with no contents attached thereto, allowing the synthetic resin container 1 to be recycled. In addition, since the slit 6 serves as an outside air introduction groove, when the inner layer body 3 is separated from the outer layer body 2, air is introduced between the outer layer body 2 and the inner layer body 3 through the slit 6, and the inner layer body 3 can be easily separated from the outer layer body 2 using the slit 6 as a starting point.

[0064] Furthermore, the method for manufacturing a synthetic resin container 1 according to this embodiment is a method for manufacturing a synthetic resin container 1 by stretch-blow molding a preform 11, the preform 11 having an outer body 12 and an inner body 13 laminated on the inner surface of the outer body 12, the preform 11 having a cylindrical mouth 14, a body 15 located below the mouth 14, and a bottom 19 closing the lower end of the body 15, the upper end of the outer body 12 being located lower than the upper end of the inner body 13, the outer body 12 having a slit 16 extending downward from the upper end, and the method is configured to include the steps of molding the outer body 12 and the inner body 13, fitting the inner body 13 to the inner peripheral surface of the outer body 12 to form the preform 11, and stretch-blow molding the preform 11 to form the container body 10. By adopting this configuration, when the inner layer body 3 is removed from the outer layer body 2 to the outside, the slit 6 formed by blow molding the slit 16 opens circumferentially, allowing the upper end of the outer layer body 2 to expand in diameter. Therefore, the inner layer body 3 contained within the outer layer body 2 can be easily removed to the outside through the expanded upper end of the outer layer body 2. The inner layer body 3 and the attached cap 20 with the contents attached thereto can be easily separated from the outer layer body 2 with no contents attached thereto, allowing the synthetic resin container 1 to be recycled. Furthermore, since the slit 6 serves as an outside air introduction groove, when the inner layer body 3 is separated from the outer layer body 2, air is introduced between the outer layer body 2 and the inner layer body 3 through the slit 6, and the inner layer body 3 can be easily separated from the outer layer body 2 using the slit 6 as a starting point.

[0065] Next, the container body 110 according to the second embodiment of the present disclosure will be specifically illustrated and described with reference to the drawings.

[0066] 8, a container body 110 according to a second embodiment of the present disclosure has a double layer structure including an outer layer 2 and an inner layer 3. The outer shape of the container body 110 is bottle-shaped, having a cylindrical mouth 4, a shoulder 7 located below the mouth 4 and expanding in diameter downward from the lower end of the mouth 4, a cylindrical body 5 connected to the lower end of the shoulder 7 and forming a storage space S for the contents, and a bottom 9 closing the lower end of the body 5.

[0067] The container body 110 comprises an outer layer 2 that forms the outer shell of the body 5, and an inner layer 3 that is separably laminated on the inner surface of the outer layer 2. As shown in Figures 8 and 9, the upper end of the outer layer 2 is located lower than the upper end of the inner layer 3, and an annular locking flange 4b ​​provided at the upper end of the inner layer 3 is placed on the upper end surface of the outer layer 2.

[0068] As shown in Fig. 9, the mouth 4 of the inner layer body 3 has a cylindrical mouth inner wall 4c and a locking flange 4b ​​extending radially outward from the upper end of the mouth inner wall 4c in a substantially horizontal direction. In this embodiment, the locking flange 4b ​​is annular, but its shape is not limited thereto, and it may be composed of a plurality of locking pieces.

[0069] The inner layer body 3 can be formed into a bag-like shape thinner than the outer layer body 2 using a synthetic resin material such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyamide (nylon), or ethylene-vinyl alcohol copolymer (EVOH), and is separably laminated to the inner surface of the outer layer body 2. In this embodiment, the inner layer body 3 is formed of the same polyethylene terephthalate as the outer layer body 2. The inner layer body 3 and the outer layer body 2 may be made of different synthetic resin materials, or the inner layer body 3 may be thicker than the outer layer body 2. The interior of the inner layer body 3 forms a storage space S that communicates with the opening of the mouth portion 4. This storage space S can contain, for example, food seasonings such as cooking oil and soy sauce, beverages, cosmetics such as lotion, and toiletries such as shampoo, conditioner, and liquid soap. Separation of the inner layer body 3 from the inner surface of the outer layer body 2 may be achieved by separation from an adhered state, separation from a pseudo-adhered state in the case of incompatible resin laminates, or separation from a tightly adhered state.

[0070] On the other hand, the outer layer body 2 constituting the container body 110 comprises a mouth outer wall 4d, an annular protrusion 4e protruding radially outward from the upper part of the mouth outer wall 4d, and a neck ring 8 extending substantially horizontally radially outward below the annular protrusion 4e, as shown in Fig. 9. Also, as shown in Fig. 9, the upper end of the mouth outer wall 4d abuts against and is locked to the lower surface of the locking flange 4b, thereby determining the vertical position of the outer layer body 2 relative to the inner layer body 3.

[0071] As shown in Fig. 9, the outer layer body 2 has a plurality of slits 6 extending downward from the upper end portion. The slits 6 extend from the annular protrusion 4e located at the upper end portion of the outer layer body 2 in the mouth portion 4, across the neck ring 8, and to a part of the shoulder portion 7. In this embodiment, the slits 6 are provided at four equally spaced locations in the circumferential direction.

[0072] In this embodiment, as shown in FIG. 9 , the slit 6 includes a constant-width portion 6a that extends linearly downward from the upper end of the outer layer 2 with a constant width, and a widened portion 6b that widens circumferentially at the lower end of the slit 6. That is, the slit 6 opens upward and penetrates radially. As shown in FIG. 9 , the widened portion 6b is drop-shaped, like a dripping liquid. Note that the widened portion 6b may have any shape, including a drop-shaped, triangular, trapezoidal, circular, or elliptical shape, as long as it is wider circumferentially than the constant-width portion 6a. However, it is preferable that the lower end of the slit 6 has an R-shape. In this embodiment, the vertical distance Hc from the lower end of the neck ring 8 to the lower end of the widened portion 6b is approximately 8 mm, and the lower end of the slit 6 terminates at the shoulder 7.

[0073] As described above, the widened portion 6b formed at the lower end of the slit 6 is drop-shaped with a rounded surface, which makes it difficult for stress to concentrate at the lower end of the slit 6 when the inner layer body 3 is removed from the outer layer body 2 while the slit 6 is opened circumferentially, making the slit 6 less likely to tear. In addition, the widened portion 6b having a drop-shaped rounded surface formed at the lower end of the slit 6 makes it easier for the mouth outer wall 4d between the slits 6 in the circumferential direction of the outer layer body 2 to open radially outward, making it easier to remove the inner layer body 3 from the outer layer body 2.

[0074] In this embodiment, the widened portion 6b of the slit 6 is formed by stretching the lower end of the slit 16 in the circumferential direction when a preform 111 (see FIG. 10) described later is biaxially stretch blow molded. Here, the radial distance B from the central axis O1 of the outer surface of the lower end of the slit 6 and the radial distance A from the central axis O1 of the outer surface of the lower end of the mouth portion 4 are 1.0

[0075] ​The number and length of the slits 6 can be changed in various ways. In addition to the configuration in which the slits 6 terminate midway in the shoulder portion 7 as in this embodiment, they may extend beyond the shoulder portion 7 to a part of the body portion 5, or may terminate at the lower end of the shoulder portion 7. The slits 6 only need to extend at least beyond the lower end of the mouth portion 4 to a part of the shoulder portion 7. With this configuration, the slits 6 open in the circumferential direction, thereby expanding the diameter of the upper end of the outer layer body 2 and making it easier to pull the inner layer body 3 out of the outer layer body 2. Note that the range (lower limit) of the mouth portion 4 refers to the range below the neck ring 8 in Figure 9 where the outer diameter of the mouth outer wall 4d does not change.

[0076] In this embodiment, multiple slits 6 are arranged in a row at equal intervals in the circumferential direction. With this configuration, the upper end of the outer layer body 2 is large and expands in diameter evenly in the circumferential direction, making it easier to pull the inner layer body 3 out of the outer layer body 2.

[0077] When molding the container body 110 by stretch blow molding a preform 111 (see Figures 10 and 11) described below, for example, the neck ring 8 can be attached to the mold without tilting the preform 111 by abutting the lower surface of the neck ring 18 against the reference surface of the blow molding mold.

[0078] In this embodiment, when the inner layer body 3 is removed from the outer layer body 2, the slits 6 open in the circumferential direction, causing the shoulder portion 7 to deform in a direction that increases the inclination relative to the horizontal direction, thereby expanding the diameter of the upper end portion of the outer layer body 2. Therefore, the inner layer body 3 contained within the outer layer body 2 can be easily removed to the outside through the expanded upper end portion of the outer layer body 2.

[0079] In this embodiment, as in the first embodiment, the slit 6 serves as an outside air introduction groove when the outer layer 2 and the inner layer 3 are separated. When the user has finished using the contents in the inner layer 3, in order to recycle the container body 110, they separate it by grasping the locking flange 4b ​​(see Figure 9) of the inner layer 3 and pulling it upward from inside the outer layer 2. At this time, outside air is introduced into the space between the outer layer 2 and the inner layer 3 through the slit 6, which functions as an outside air introduction groove, so that the inner layer 3 can be easily separated from the outer layer 2 and easily pulled out to the outside of the outer layer 2. Note that an outside introduction groove other than the slit 6 may be provided. For example, an outside air introduction groove may be provided in the body 5 or the bottom 9.

[0080] The material forming the outer layer body 2 is the same as that in the first embodiment, and further explanation will be omitted here. The portion of the outer layer body 2 corresponding to the trunk portion 5 is flexible, and can be squeezed to become depressed, and can also return to its original shape from the depressed state.

[0081] As in the first embodiment, an attachment cap may be attached to the opening 4 of the container body 110. In this case, for example, the locking flange 4b ​​provided on the upper end of the inner layer body 3 may be extended further radially outward so that the locking flange 4b ​​of the inner layer body 3 engages with the attachment cap. With this configuration, the inner layer body 3 engaged with the attachment cap can be removed from inside the outer layer body 2 by pulling the attachment cap upward, as in the first embodiment.

[0082] The container body 110 configured in this manner can pour the contents from the storage space S to the outside by, for example, tilting it so that the opening 4 is positioned below the bottom 9. Furthermore, in the container body 110 of this embodiment, a slit 6 is provided from the upper end of the outer layer 2 to the shoulder 7, and therefore the outer layer 2 expands outward in the region where this slit 6 is provided, making it easier to separate the inner layer 3 from the outer layer 2. Therefore, when the user has finished using the contents in the storage space S, the user can easily separate the inner layer 3 from the outer layer 2 using this slit 6 as a starting point and pull it out of the outer layer 2.

[0083] When the inner layer body 3 is pulled upward from inside the outer layer body 2, the pulled inner layer body 3 presses against the outer layer body 2 at the shoulder portion 7 from the inside, spreading it radially outward, causing the slits 6 provided in the shoulder portion 7 to open in the circumferential direction and displacing the upper end of the outer layer body 2 radially outward. This radially outward deformation of the upper end of the outer layer body 2 causes the opening to expand in diameter, allowing the inner layer body 3 to be easily removed to the outside of the outer layer body 2. Furthermore, because an expanded portion 6b is provided at the lower end of the slit 6, stress concentration is less likely to occur at the lower end of the slit 6 even when the slit 6 opens in the circumferential direction.

[0084] This container body 110 can be formed by stretch blow molding a synthetic resin preform 111 according to the second embodiment of the present disclosure, as shown in FIGS.

[0085] The preform 111 has a double structure including an outer body 12 made of synthetic resin that forms the outer layer body 2 and an inner body 13 made of synthetic resin that forms the inner layer body 3. The outer shape of the preform 111 is a bottomed tubular shape (approximately test tube shape) having a cylindrical mouth portion 14, a cylindrical body portion 15 that continues below the mouth portion 14, and a bottom portion 19 that closes the lower end of the body portion 15. The mouth portion 14 is formed in a shape that corresponds to the mouth portion 4 of the container body 110. That is, the mouth portion inner wall 14c, the mouth portion outer wall 14d, the annular protrusion 14e, the locking flange 14b, and the neck ring 18 of the preform 111 have substantially the same shapes as the mouth portion inner wall 4c, the mouth portion outer wall 4d, the annular protrusion 4e, the locking flange 4b, and the neck ring 8 of the container body 110. That is, in the preform 111, the portion above the neck ring 18 is a non-stretched region that has substantially the same shape as the mouth portion 4 of the container body 110. In this specification, the non-stretched region refers to a region whose size does not change substantially before and after stretch blow molding. In addition, at least the upper part of the straight portion below the neck ring 18 is also a non-stretched region.

[0086] A slit 16 is provided downward from the upper end of the outer body 12. In this embodiment, the lower end of the slit 16 terminates in the stretched region of the straight portion and forms part of the shoulder 7 after stretch blow molding. On the other hand, the upper part of the slit 16 is located in the non-stretched region, and the shape is generally maintained even after stretch blow molding.

[0087] The preform 111 has a tapered portion 17 whose diameter tapers from the lower end of the straight portion toward the body portion 15. The region of this tapered portion 17 is an elongated region, and as shown in Fig. 10, the outer body 12 and the inner body 13 are separated from each other in the radial direction. The bottom portion 19 is formed in a curved shape (hemispherical shape). Note that the symbol O2 indicates a central axis common to the mouth portion 14, body portion 15, and bottom portion 19.

[0088] In this embodiment, the slit 16 of the preform 111 does not widen from the upper end beyond the neck ring 18 to the lower end of the slit 16, and has the shape shown in Fig. 11 in a plan view. Note that Fig. 11 only depicts the outer body 12 in the AA cross section shown in Fig. 10. The slit 16 has a first surface 16a extending along the vertical direction in Fig. 11 and a second surface 16b extending along the radial direction, and the provision of the first surface 16a allows the split mold that forms the slit 16 to be easily removed in the vertical direction in Fig. 11.

[0089] In this embodiment, the vertical distance Hp from the lower end of the neck ring 18 to the lower end of the slit 16 is set to about 5 mm, and the lower end of the slit 16 terminates near the upper end of the reduced diameter portion 17. Note that the vertical distance Hp is 1.0 mm after stretch blow molding.

[0090] ​The outer body 12 is formed of the same synthetic resin material as the outer layer body 2, namely, polyethylene terephthalate (PET). The inner body 13 is also formed of the same synthetic resin material as the inner layer body 3, polyethylene terephthalate (PET). The inner body 13 is formed thinner than the outer body 12 and is laminated on the inner surface of the outer body 12 with gaps so as to cover the entire inner surface. This laminated state may be configured so that the inner body 13 is in close contact with the entire surface or in partial contact. The inner body 13 may be configured to be thicker than the outer body 12. Furthermore, the inner body 13 (inner layer body 3) may be made of a different synthetic resin from the outer body 12 (outer layer body 2) to facilitate separation from the outer body 12. For example, if the outer body 12 is made of PET and the inner body 13 is made of PP, separation will be easier. Furthermore, the outer body 12 and the inner body 13 may be formed of a single-layer structure formed of only a single synthetic resin, or may be formed of multiple synthetic resins to improve barrier properties and content resistance.

[0091] The procedure for carrying out the manufacturing method for the container body 110 according to this embodiment is similar to the procedure for manufacturing the container body 10 according to the first embodiment by performing steps S101 to S104 shown in FIG. 7, and therefore further explanation will be omitted here.

[0092] As described above, the container body 110 according to this embodiment includes an outer layer 2 and an inner layer 3 detachably laminated on the inner surface of the outer layer 2. The container body 110 includes a cylindrical mouth 4, a shoulder 7 that expands downward from the lower end of the mouth 4, a body 5 that connects to the lower end of the shoulder 7 and forms a storage space S for the contents, and a bottom 9 that closes the lower end of the body 5. The upper end of the outer layer 2 is located below the upper end of the inner layer 3, and the outer layer 2 has a slit 6 that extends downward from the upper end. By adopting this configuration, when the inner layer 3 is removed from the outer layer 2, the slit 6 opens circumferentially, expanding the diameter of the upper end of the outer layer 2. Therefore, the inner layer 3 contained within the outer layer 2 can be easily removed through the expanded upper end of the outer layer 2. The inner layer 3 with the contents attached and the outer layer 2 without the contents attached can be easily separated to recycle the container body 110. In addition, since the slit 6 acts as an air introduction groove, when the inner layer 3 is separated from the outer layer 2, air is introduced between the outer layer 2 and the inner layer 3 through the slit 6, making it possible to easily separate the inner layer 3 from the outer layer 2 using the slit 6 as a starting point.

[0093] Furthermore, in the container body 110 according to this embodiment, the slit 6 is configured to have a widened portion 6b at its lower end that widens in the circumferential direction. By adopting this configuration, stress is less likely to concentrate at the lower end of the slit 6 when the inner layer body 3 is removed from the outer layer body 2 while the slit 6 is opened in the circumferential direction, and therefore the slit 6 is less likely to tear. Furthermore, by forming the widened portion 6b at the lower end of the slit 6, the outer wall 4d of the opening between the slits 6 in the circumferential direction of the outer layer body 2 can be more easily opened radially outward, making it easier to remove the inner layer body 3 from the outer layer body 2.

[0094] In the container body 110 according to this embodiment, the lower end of the slit 6 terminates at the shoulder 7, and the radial distance B from the central axis O1 of the outer surface of the lower end of the slit 6 and the radial distance A from the central axis O1 of the outer surface of the lower end of the mouth 4 are 1.0

[0095] 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.

[0096] For example, in the first embodiment, the attachment cap 20 is provided with a pouring hole and is configured to discharge the contents to the outside by tilting the container, but the present invention is not limited to this configuration and the contents may be discharged to the outside by pressing the body 5 of the outer layer 2. Furthermore, the synthetic resin container 1 may be used as a container with a pump, in which case the attachment cap 20 may be configured to have a pump attached to it.

[0097] ​In the second embodiment, the widened portion 6b formed at the lower end of the slit 6 is configured to be drop-shaped, but this is not limited to this. It is sufficient that the circumferential width of the widened portion 6b is wider than that of the constant-width portion 6a. Therefore, the widened portion 6b may have a shape other than drop-shaped by changing the amount of extension of the lower end of the slit 6 during the manufacture of the container body 110, revising the shape of the slit 16 in the preform 111, or forming the container body 110 by another method. The widened portion 6b may have any shape, including a drop-shaped shape, a triangular shape, a trapezoidal shape, a perfect circle, or an ellipse. However, it is preferable that the lower end of the slit 6 has an R-shape. [Explanation of symbols]

[0098] 1. Synthetic resin containers 2 Outer body 3. Inner layer 4 Mouth 4a Annular protrusion (first engagement portion) 4b Locking flange 4c Inner wall of mouth 4d Mouth outer wall 4e Annular protrusion (second engagement portion) 5. Torso 6 Slits 6a Equal width section 6b Widened section 7 Shoulder 8 Neck Rings 9 Bottom 10 Container body 11 Preform 12 External body 13 Inner body 14 Mouth 14a Annular protrusion 14b Locking flange 14c Inner wall of mouth 14d Mouth outer wall 14e Annular protrusion 15 Torso 16 Slit 16a 1st page 16b 2nd side 17 Reduced diameter part 18 Neck Ring 19 Bottom 20 Mounting cap 21 Cap body 21a Outer wall 22 Ceiling wall 22a Annular protrusion 22b Stepped section 23 Seal Wall 23a Engagement protrusion (first engagement part) 24 Inner wall 25 Lid 26 Lid body peripheral wall 26a Engagement protrusion 27 Top Wall 28 Breakaway fragment 28a Peripheral wall 28a1 Engagement protrusion (second engagement part) 28b Knob 28c Weakened part 110 Container body 111 Preform O1,O2 Center axis S Storage space

Claims

1. a container body having an outer layer and an inner layer detachably laminated on the inner surface of the outer layer; an attachment cap attached to the container body; A synthetic resin container comprising: The container body is a cylindrical opening portion to which the attachment cap is attached; a body portion located below the mouth portion and forming a storage space for contents; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer layer body is located lower than the upper end of the inner layer body, The outer layer body has a slit extending downward from an upper end portion thereof, A synthetic resin container, wherein the mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner layer body and an outer wall of the mouth portion provided at the upper end of the outer layer body.

2. The synthetic resin container according to claim 1 , wherein a plurality of the slits are provided in the circumferential direction.

3. the opening of the inner layer body and the attachment cap have a first engaging portion that engages with and fixes the two together; 3. The synthetic resin container according to claim 1, wherein the upper end of said outer layer body and said attachment cap have second engaging portions that engage with each other to fix them together.

4. A detachable piece is provided at the bottom of the mounting cap by a weakened portion, The synthetic resin container according to claim 3 , wherein the second engaging portion on the attachment cap side is provided on the release piece.

5. The container body further includes a shoulder portion whose diameter increases downward from the lower end of the mouth portion, 3. The synthetic resin container according to claim 1, wherein the slit extends from an upper end of the outer layer to at least a part of the shoulder portion.

6. A synthetic resin preform for use in stretch blow molding, comprising an outer body and an inner body laminated on the inner surface of the outer body, A cylindrical mouth portion, a body portion located below the mouth portion; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer body is located lower than the upper end of the inner body, The outer body has a slit extending downward from an upper end thereof, The preform, wherein the mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner body and an outer wall of the mouth portion provided at the upper end of the outer body.

7. A method for manufacturing a synthetic resin container by stretch blow molding a preform, comprising: The preform has an outer body and an inner body laminated on the inner surface of the outer body, A cylindrical mouth portion, a body portion located below the mouth portion; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer body is located lower than the upper end of the inner body, The outer body has a slit extending downward from an upper end thereof, the mouth portion is formed by laminating an inner wall of the mouth portion provided at the upper end of the inner body and an outer wall of the mouth portion provided at the upper end of the outer body, molding the outer body and the inner body; fitting the inner body onto the inner circumferential surface of the outer body to form a preform; stretch blow molding the preform to form a container body; A method for manufacturing a synthetic resin container, comprising:

8. A container body having an outer layer and an inner layer separably laminated on the inner surface of the outer layer, A cylindrical mouth portion, a shoulder portion whose diameter increases downward from the lower end of the mouth portion; a body portion that is connected to a lower portion of the shoulder portion and forms a storage space for contents; a bottom portion that closes the lower end of the body portion; Equipped with The upper end of the outer layer body is located lower than the upper end of the inner layer body, The outer layer body has a slit extending downward from an upper end portion thereof, The container body has a mouth portion formed by laminating an inner wall of the mouth portion provided at the upper end of the inner layer body and an outer wall of the mouth portion provided at the upper end of the outer layer body.

9. The container body according to claim 8 , wherein the slit has a widened portion at a lower end thereof that widens in the circumferential direction.

10. a lower end of the slit terminates at the shoulder; The container body according to claim 8 or 9, wherein a radial distance B from the central axis of the outer surface of the lower end of the slit and a radial distance A from the central axis of the outer surface of the lower end of the mouth have a relationship of 1.0 < B / A ≦ 1.4.

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