Sealing structure of the container mouth

Abstract

The amount of resin material used in the sealing cap will be further reduced. [Solution] A cap (2) is attached to a container mouth (4), and the cap (2) comprises a top surface (20) and a skirt portion (21) hanging down cylindrically from the periphery of the top surface (20), and has a cutout portion (26) formed by cutting through the skirt portion (21) in the thickness direction on the periphery except for the lower edge side of the skirt portion (21) on which a female thread (25) is formed on the inner periphery, and at least the area covering the cutout portion (26) is covered with a film material (3).

Description

[Technical Field]

[0001] The present invention relates to a sealing structure for a container mouth, and more particularly to a sealing structure for a container mouth in which a sealing cap is attached to the container mouth. [Background technology]

[0002] Conventionally, when filling and sealing a resin container such as a PET bottle with a beverage or other contents, a resin cap is attached to the opening of the container. In recent years, PET bottles have been made thinner in order to reduce the amount of resin used, and similarly, attempts have been made to reduce the amount of resin used in the sealing caps.

[0003] For example, in Patent Document 1, as shown in FIG. 4, an attempt is made to reduce the amount of material resin used by forming a plurality of recessed portions C44 at intervals in the circumferential direction on a locking protrusion C32 arranged on the inner surface of a tamper-evident bottom portion C18. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-118381 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the background art, the present inventors have conducted extensive research to further reduce the amount of resin material used in sealing caps, and as a result have completed the present invention. [Means for solving the problem]

[0006] The sealing structure for a container mouth according to the present invention is a sealing structure for a container mouth formed by attaching a sealing cap to the container mouth, wherein the cap has a top surface and a skirt portion that hangs down cylindrically from the periphery of the top surface, and a cutout portion that penetrates the skirt portion in the thickness direction is provided on the periphery except for the lower edge side of the skirt portion, which has a female thread formed on its inner surface, and at least the area that covers the cutout portion is covered with a film material. In the sealing structure for a container mouth according to the present invention, the plurality of cutouts cut out so as to extend vertically can be arranged at predetermined intervals in the circumferential direction. Furthermore, the top surface can have an outer seal portion that hangs down cylindrically from the inner surface of the top surface and contacts the outer peripheral surface of the open end of the container mouth, and the cutouts cut out so as to extend vertically can be cut out at a portion of the top surface radially outward of the outer seal portion so as to reach the peripheral edge of the top plate portion. In addition, the female thread provided on the inner peripheral surface of the skirt portion can be arranged intermittently along the circumferential direction, and the cutout portion can be arranged in the area where the female thread is divided. The area covered by the film material may extend beyond the lower edge of the cap to below the portion of the container mouth where the cap is attached, and the lower end of the film material may be engaged with this area. Preferably, the container mouth may have a bead portion extending circumferentially below the portion of the container mouth where the cap is attached, and the lower end of the film material may be engaged with the bead portion. A break line may be formed in the film material along the lower edge of the cap, and the film material may be a tubular heat-shrinkable film.

[0007] Furthermore, the cap according to the present invention is a cap that is attached to the mouth of a container to seal the mouth of the container, and includes a top surface and a skirt portion that hangs down cylindrically from the periphery of the top surface, and can be configured such that a cutout portion is formed by cutting through the skirt portion in the thickness direction on the circumferential surface except for the lower edge side of the skirt portion, which has a female thread formed on its inner circumferential surface. In the cap of the present invention, the female thread provided on the inner surface of the skirt portion can be provided intermittently along the circumferential direction, and the cutout portion can be arranged in the area where the female thread is divided. [Effects of the Invention]

[0008] According to the present invention, the amount of resin material used in the sealing cap can be significantly reduced. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a half-sectional view showing an example of a sealing structure for a container opening according to an embodiment of the present invention. [Figure 2] 1 is a plan view showing an example of a cap used in a sealing structure for a container mouth according to an embodiment of the present invention. [Figure 3] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 4] FIG. 1 is an explanatory diagram showing a synthetic resin container lid shown in FIG. 1 of Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Fig. 1 is a half-side cross-sectional view showing an example of a sealing structure for a container mouth according to this embodiment. In Fig. 1, a vertical cross section including a central axis C is shown on the left side of the drawing, and the up-down, left-right, and length-width directions defined for the sealing structure 1 are defined in the state shown in Fig. 1.

[0012] The sealing structure 1 in this embodiment seals the container mouth 4 when filling and sealing contents such as beverages into various containers, using a sealing cap 2 attached to the container mouth 4 and a film material 3 covering the cap 2 attached to the container mouth 4. Details of the film material 3 will be described later, but Fig. 1 shows the film material 3 covering the cap 2 in a schematic manner, and the thickness of the film material 3 that appears in the cross section is exaggerated.

[0013] The cap 2 is made of a synthetic resin, for example, an olefin resin such as low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ethylene-propylene copolymer, homopolypropylene, etc., prepared alone or by blending two or more types, and can be molded into a predetermined shape by injection molding, compression molding, etc. using a material resin to which various additives have been added as necessary.

[0014] Here, Fig. 2 is a plan view of the cap 2 used in the sealing structure 1 shown in Fig. 1, and Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. In the example shown, the cap 2 includes a disk-shaped top surface portion 20 and a skirt portion 21 that hangs down in a cylindrical shape from the periphery of the top surface portion 20.

[0015] On the inner surface of the top surface 20, a cylindrical inner seal portion 22 is formed, which hangs down concentrically with the skirt portion 21 and contacts the inner peripheral surface of the open end side of the container mouth 4, and a cylindrical outer seal portion 23 is formed, which contacts the outer peripheral surface of the open end side of the container mouth 4. In the example shown in the figure, by forming these portions, a liquid-tight seal is more reliably achieved when the cap 2 is attached to the container mouth 4. In the cross section shown in FIG. 1, the parts that are shown overlapping each other are actually elastically deformed and in close contact with each other.

[0016] The skirt portion 21 has anti-slip knurling 24 formed on its outer peripheral surface, and a female thread 25 formed on its inner peripheral surface. The female thread 25 formed on the inner peripheral surface of the skirt portion 21 is not particularly limited in terms of its specific shape, as long as it can be threadedly engaged with the male thread 40 formed on the outer peripheral surface of the container opening 4.

[0017] In this embodiment, the peripheral surface of the skirt portion 21, excluding the lower edge side, is provided with a cutout portion 26 that penetrates the skirt portion 21 in the thickness direction. This makes it possible to significantly reduce the amount of resin material used when molding the cap 2 compared to conventional methods.

[0018] When providing such a cutout portion 26, the lower edge of the skirt portion 21 is not cut out, and the lower edge of the skirt portion 21 is maintained in a continuous shape along the circumferential direction, thereby preventing the lower edge of the skirt portion 21 from widening outward in a fan-like manner, which would interfere with the attachment of the cap 2 by screwing it onto the container mouth 4.

[0019] Although the provision of the cutouts 26 may result in insufficient strength of the skirt portion 21, it is preferable to appropriately design the shape and position of the cutouts 26 so as not to result in insufficient strength of the skirt portion 21. From this perspective, it is preferable that the cutouts 26 are provided so as to extend in the vertical direction, leaving the lower edge side of the skirt portion 21. Furthermore, it is preferable that a plurality of cutouts 26 extending in the vertical direction are arranged at predetermined intervals along the circumferential direction so that strength is ensured by the portions located between adjacent cutouts 26 in the circumferential direction.

[0020] 2, the cutout portion 26 extending in the vertical direction preferably wraps around the top surface 20, and is formed such that the portion of the top surface 20 radially outward of the outer seal portion 23 is cut out from the periphery toward the center of the top surface 20. This allows the amount of resin material used to be further reduced without impairing the sealing performance of the cap 2.

[0021] Furthermore, the female threads 25 provided on the inner peripheral surface of the skirt portion 21 are preferably provided discontinuously along the circumferential direction, and the notches 26 are preferably arranged so as to extend vertically in the regions where the female threads 25 are separated. In other words, the female threads 25 are preferably provided at intervals along the circumferential direction in the regions located between the notches 26 adjacent in the circumferential direction. In Patent Document 1, as shown in FIG. 4, a plurality of cutout portions C28 are provided at intervals along the circumferential direction of the female thread C26, but in this embodiment, it can also be said that the cutout portions 26 are arranged to correspond to these cutout portions C28.

[0022] When the cap 2 having the cutout 26 formed on the peripheral surface of the skirt portion 21 is attached to the container mouth 4 as described above, the container mouth 4 is exposed through the cutout 26. For this reason, in this embodiment, at least the area covering the cutout 26 is covered with the film material 3 to prevent foreign matter from entering through the cutout 26 and soiling the container mouth 4.

[0023] The film material 3 is not particularly limited as long as it can cover the cutout portion 26 and prevent the intrusion of foreign matter, but it is preferable to use a heat-shrinkable film made from, for example, a polystyrene resin, a polyester resin, a polyvinyl chloride resin, a polypropylene resin, a polyethylene resin, or a mixture thereof, formed by a T-die method, an inflation method, or the like. The heat-shrinkable film may be transparent or translucent, or may be colored. If necessary, it may be printed.

[0024] Such a heat-shrinkable film can be cut into strips of a specified size, formed into a cylindrical shape by gluing both longitudinal ends together, placed around the cap 2 attached to the container mouth 4, and heat-shrunk using a heating means such as an oven, so that the area covering the cutout 26 is covered. In Figure 1, the film material 3 is shown schematically as having a gap between it and the cap 2 and the container mouth 4, but it is in close contact with these to the extent that it can follow when the heat-shrinkable film heat-shrinks.

[0025] From the viewpoint of preventing the intrusion of foreign matter between the lower edge of the cap 2 and the container mouth 4, the area covered by the film material 3 preferably extends beyond the lower edge of the cap 2 and below the portion of the container mouth 4 where the cap 2 is attached. Furthermore, it is preferable that the lower end of the film material 3 closely contacts this area and is engaged so as to be fixed without any vertical displacement. Generally, in resin containers such as PET bottles, a bead portion 41 extending along the circumferential direction is formed on the container mouth 4 below the portion where the cap 2 is attached. It is preferable that the lower end of the film material 3 be engaged with the underside of this bead portion 41. In this case, it is preferable that the film material 3 has an easy-to-break line 30, such as a perforation, formed along the lower edge of the cap 2.

[0026] When the cap 2 attached to the container opening 4 is gripped together with the film material 3 and rotated in the opening direction, the cap 2 is guided by the male thread 40 on the container opening 4 and the female thread 25 on the cap 2, and rises axially relative to the container opening 4 while rotating. Because the lower end of the film material 3 is fixed without vertical displacement, the breakable line 30 breaks as the upper end of the film material 3 rises with the cap 2, and the lower end of the film material 3 is separated. This provides tamper-evident functionality, clearly indicating that the cap 2 has been opened. While Patent Document 1 provides a tamper-evident bottom portion C18 to achieve tamper-evident functionality, this embodiment eliminates the need for a corresponding component, thereby significantly reducing the amount of resin material used.

[0027] Although the present invention has been described above by showing preferred embodiments, the present invention is not limited to the above-described embodiments. It goes without saying that the configurations described in the above-described embodiments can be combined in any desired manner and that various modifications can be made within the scope of the present invention. [Explanation of symbols]

[0028] 1 Sealing structure 2 Caps 20 Top section 21 Skirt Club 23 Outer seal 25 Female thread 26 Cutout 3 Film material 30 Easy Breaking Line 4 Container opening 41 Bead section

Claims

1. A sealing structure for a container mouth portion in which a sealing cap is attached to the container mouth portion, The cap includes a top surface portion and a skirt portion that hangs down in a cylindrical shape from a peripheral edge of the top surface portion, a notch formed by cutting through the skirt portion in a thickness direction is provided on the peripheral surface of the skirt portion except for the lower edge side of the skirt portion on which the internal thread is provided on the inner peripheral surface, A sealing structure for a container opening, characterized in that at least an area covering the notch is covered with a film material.

2. 2. The sealing structure for a container mouth according to claim 1, wherein a plurality of the notches extending in the vertical direction are arranged at predetermined intervals along the circumferential direction.

3. an outer seal portion is formed on the top surface portion, the outer seal portion being tubular and hanging down from the inner surface of the top surface portion and contacting the outer peripheral surface of the opening end side of the container mouth portion; The sealing structure of a container mouth as described in claim 2, wherein the cutout portion extending vertically is provided so as to cut out a portion of the top surface radially outward from the outer seal portion of the top surface and reach the peripheral edge of the top surface.

4. 3. A sealing structure for a container mouth as described in claim 2, wherein the female threads provided on the inner peripheral surface of the skirt portion are provided intermittently along the circumferential direction, and the cutout portion is arranged in the area where the female threads are divided.

5. A sealing structure for a container mouth as described in claim 1, wherein the area extending beyond the lower edge of the cap to below the portion of the container mouth where the cap is attached is covered with the film material, and the lower end side of the film material is engaged with the area.

6. a bead portion extending along a circumferential direction is formed on the container opening below a portion where the cap is attached, 6. The sealing structure for a container mouth according to claim 5, wherein a lower end side of the film material is engaged with the bead portion.

7. A breakable line is formed in the film material along the lower edge of the cap. The sealing structure for a container mouth according to claim 6.

8. The sealing structure for a container mouth according to any one of claims 1 to 7, wherein the film material is a tubular heat-shrinkable film.

9. A cap that is attached to a container mouth and seals the container mouth, a top surface portion and a skirt portion that hangs down in a cylindrical shape from a periphery of the top surface portion, A cap characterized in that a notch portion is formed by cutting through the skirt portion in the thickness direction on the peripheral surface except for the lower edge side of the skirt portion, which has a female thread formed on the inner peripheral surface.

10. 10. The cap according to claim 9, wherein the female threads formed on the inner peripheral surface of the skirt portion are provided intermittently along the circumferential direction, and the notch portions are disposed in areas where the female threads are interrupted.

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