Mouth plug and packaging container equipped with the same

Abstract

To provide a mouth plug hardly impairing sealing performance even when internal pressure of a packaging container changes, and to provide a packaging container equipped with the same.SOLUTION: A mouth plug according to the present invention comprises a spout and a cap attached to the spout. The cap comprises a top surface portion, a skirt portion extending vertically from an edge of the top surface portion, and a cylindrical inner ring provided on the top surface portion at a distance from the skirt portion. The spout comprises a cylindrical pouring tubular portion, a flange portion connected to one end of the pouring tubular portion, and a protruding portion protruding from the whole circumference of the inner peripheral surface of the pouring tubular portion and in contact with the whole circumference of the inner peripheral surface of the inner ring of the cap attached to the spout.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a plug and a packaging container provided with the same. [Background technology]

[0002] 2. Description of the Related Art Packaging containers for storing liquids and the like that are provided with a plug for pouring out the contents are known. The plug is composed of, for example, a spout having a cylindrical pouring outlet portion and a flange, and a cap attached to the spout.

[0003] In such plugs, an inner ring that comes into close contact with the inner circumferential surface of the spout outlet may be provided on the top surface of the cap to prevent the contents from leaking out (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-179107 A [Patent Document 2] JP 2002-068233 A [Patent Document 3] Patent No. 4330234 Summary of the Invention [Problem to be solved by the invention]

[0005] However, depending on the environment in which the packaging container is used, the contents may leak even with the inner ring. For example, the stopper may become distorted due to an increase in internal pressure caused by dropping the packaging container or a decrease in internal pressure caused by cooling after hot filling, which may reduce the adhesion between the inner surface of the spout and the inner ring, resulting in a loss of sealing ability.

[0006] An object of the present invention is to provide a plug whose sealing performance is not easily impaired even when the internal pressure of the packaging container changes, and a packaging container equipped with the plug. [Means for solving the problem]

[0007] The plug of the present invention comprises a spout and a cap attached to the spout, wherein the cap comprises a top surface, a skirt portion extending vertically from an edge of the top surface, and a cylindrical inner ring provided on the top surface at a distance from the skirt portion, and the spout comprises a cylindrical pouring tubular portion, a flange portion connected to one end of the pouring tubular portion, and a protruding portion protruding from the entire circumference of the inner surface of the pouring tubular portion and in contact with the entire inner surface of the inner ring of the cap attached to the spout.

[0008] A packaging container according to the present invention comprises a container body and the above-mentioned plug attached to the container body. Effect of the Invention

[0009] According to the present invention, it is possible to provide a plug whose sealing performance is not easily impaired even when the internal pressure of the packaging container changes, and a packaging container equipped with the plug. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a vertical end view showing a schematic configuration of a plug according to an embodiment; [Diagram 2] FIG. 1 shows the state of a plug when the internal pressure of a packaging container increases [Diagram 3] FIG. 1 shows the state of a plug when the internal pressure of a packaging container increases [Figure 4] A diagram showing the state of a plug when the internal pressure of a packaging container is reduced [Diagram 5] FIG. 13 is a vertical end view showing a schematic configuration of a plug according to a modified example. [Figure 6] FIG. 13 is a vertical end view showing a schematic configuration of a plug according to a modified example. [Figure 7] FIG. 13 is a vertical end view showing a schematic configuration of a plug according to a modified example. [Figure 8] FIG. 1 is a vertical end view showing a schematic configuration of a plug according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment] Fig. 1 is a vertical end view showing a schematic configuration of a plug according to an embodiment of the present invention, and shows the plug in a state before being opened.

[0012] <Configuration> The stopper 100 includes a spout 10 and a cap 20, and is attached to the opening of a container body 1 made mainly of paper, for example. Hereinafter, the container body 1 with the stopper 100 attached thereto is referred to as a packaging container. In this specification, the rotation direction of the cap 20 when screwing the cap 20 onto the spout 10 is referred to as the stoppering direction. The stoppering direction corresponds to the left direction in FIG. 1 (the clockwise direction when viewed from above from the outside of the top surface 25 of the cap 20). The unstoppering direction is the rotation direction opposite to the stoppering direction.

[0013] (cap) The cap 20 is a member that is detachably attached to the spout 10 by screwing, and is made of, for example, polypropylene (PP). The cap 20 includes a top surface portion 25 and a cylindrical skirt portion 26 that extends vertically from the edge of the top surface portion 25. An internal thread 4b that screws into an external thread 4a formed on the spout 10 is formed on the inner circumferential surface of the skirt portion 26. An inner ring 27 that comes into close contact with the inner circumferential surface of the pouring tube portion 11 is formed on the top surface portion 25 of the cap 20.

[0014] Inner ring 27 is a cylindrical member provided on the top surface of cap 20 at a distance from skirt portion 26, and has, in order from flange portion 12 side (opposite top surface 25), first ring portion 27a and second ring portion 27b having an outer diameter larger than first ring portion 27a. The outer peripheral surface of inner ring 27 is in close contact with the inner peripheral surface of pouring tube portion 11 of spout 10, which will be described later, over the entire circumference. Also, the inner peripheral surface of inner ring 27 is in contact with protruding portion 13 of spout 10, which will be described later, over the entire circumference.

[0015] (Spout) Spout 10 is a member attached to the opening of container body 1 and used to pour out the contents, such as liquid, contained in container body 1 to the outside. Spout 10 includes a cylindrical pouring tube portion 11, a flange portion 12 connected to one end of pouring tube portion 11, and a protruding portion 13 protruding from the entire circumference of the inner circumferential surface of pouring tube portion 11.

[0016] The pouring tube portion 11 is a cylindrical member having, in order from the tip side (the end side opposite to the flange portion 12), a second tube portion 11b and a first tube portion 11a having an inner diameter smaller than that of the second tube portion 11b. A first ring portion 27a of an inner ring 27 formed on the cap 20 is inserted into the first tube portion 11a, and a second ring portion 27b is inserted into the second tube portion 11b. A male thread 4a that screws into a female thread 4b formed on the cap 20 is formed on the outer circumferential surface of the pouring tube portion 11, and a protruding portion 13 that protrudes from the entire circumference of the inner circumferential surface of the pouring tube portion 11 is formed on the inner circumferential surface of the pouring tube portion 11. From the viewpoint of sealing, it is preferable that the inner surface of the top surface portion 25 and the tip portion of the pouring tube portion 11 are in close contact over the entire circumference.

[0017] The flange portion 12 is connected to one end of the tubular pouring portion 11 and is welded to the periphery of the opening on the inner surface of the container body 1. The flange portion 12 is a flat plate-shaped member extending outward from the tubular pouring portion 11, and in this embodiment, is formed so as to extend in a direction perpendicular to the axial direction of the tubular pouring portion 11. The shape of the flange portion 12 is not limited as long as it can be joined to the container body 1, but it can be, for example, annular. The flange portion 12 and the container body 1 are joined using a known method such as welding.

[0018] The protruding portion 13 includes a cylindrical small wall portion 13a spaced apart from the inner peripheral surface of the pouring tube portion 11, a connecting portion 13b connecting the inner peripheral surface of the pouring tube portion 11 and the end of the small wall portion 13a on the flange portion 12 side, and a ring-shaped rib 13c formed around the entire circumference of the outer peripheral surface (the surface facing the inner peripheral surface of the pouring tube portion 11) of the end of the small wall portion 13a on the opposite side to the flange portion 12. The rib 13c is in line contact with the inner peripheral surface of the inner ring 27 around the entire circumference when the cap 20 is attached to the spout 10. When the cap 20 is made of a material that is hard for the spout 10, it is difficult for the cap 20 to follow the sudden deformation of the spout 10 that occurs when the packaging container is dropped, etc., but the formation of the rib 13c makes it easier for the cap 20 to follow the deformation of the spout 10, thereby suppressing liquid leakage.

[0019] When the cap 20 is attached to the spout 10, the first ring portion 27a of the inner ring 27 is inserted between the inner peripheral surface of the first cylindrical portion 11a and the rib 13c, and at this time, in order to prevent the first ring portion 27a and the connecting portion 13b from coming into contact with each other and being deformed, it is preferable that the tip of the first ring portion 27a and the connecting portion 13b are spaced apart by about 0.2 mm to 0.3 mm. In addition, by providing a contact ring (not shown) around the entire circumference of the tip of the pouring cylindrical portion 11, it is possible to make it even more difficult for the first ring portion 27a and the connecting portion 13b to come into contact with each other.

[0020] From the viewpoint of improving sealing performance, when cap 20 is attached to spout 10, it is preferable that inner ring 27 is inserted into the inner surface of pouring tube portion 11 while the tip of spout 10 is deformed so as to expand outward. That is, it is preferable that pouring tube portion 11 and inner ring 27 overlap each other, and for example, the amount of overlap between first tube portion 11a and first ring portion 27a can be φ0.1 mm.

[0021] In addition, in this embodiment, when attaching the cap 20 to the spout 10, the second cylindrical portion 11b and the second ring portion 27b are first brought into close contact with each other, and then the first cylindrical portion 11a and the first ring portion 27a are brought into close contact with each other. Since the contacts are made sequentially in this manner, the torque required to close the cap 20 can be minimized.

[0022] The spout 10 is molded from a material containing a thermoplastic resin such as low-density polyethylene (LDPE), and can be molded by an existing molding method such as injection molding or compression molding.

[0023] When the spout 10 is molded using a mold, it can be demolded by punching out the upper and lower cores with the end of the protrusion 13 opposite the flange 12 (the position of the dotted line in FIG. 1) as the parting line (PL) and by opening the two-part split mold left and right. In this case, it is preferable to punch out the core from the bottom first, since the rib 13c, which becomes the undercut, can be neatly demolded. In addition, since the plug 100 according to this embodiment is a pull-less plug, it can be used in a manufacturing method for a general spout that does not have a protrusion 13, simply by changing the PL position and the punching order of the mold.

[0024] <effect> The internal pressure of a packaging container changes depending on the environment, for example, it may rise momentarily due to the impact of dropping the packaging container, or it may decrease due to cooling after hot filling of the contents. This change in internal pressure may distort the stopper, causing the sealing property to be impaired. The stopper according to the present embodiment has been developed in consideration of such problems, and has the effect of preventing the sealing property from being impaired even if the internal pressure of the packaging container changes, and suppressing the leakage of contents such as liquids. As a specific example, the state of the stopper when the internal pressure rises and when the internal pressure decreases will be described. Figures 2 and 3 are diagrams showing the state of the stopper when the internal pressure of the packaging container rises, and Figure 4 is a diagram showing the state of the stopper when the internal pressure of the packaging container decreases. The rise in internal pressure includes the momentary rise in internal pressure caused by the impact of dropping the packaging container, and the decrease in internal pressure includes the decrease in internal pressure caused by cooling after hot filling of the contents.

[0025] When the internal pressure of the packaging container rises, high pressure is applied to the inner surface of the plug 100, and high pressure is also applied outward to the inner peripheral surface of the inner ring 27 (white arrow in FIG. 2). Then, the outer peripheral surface of the inner ring 27 is pressed against the inner peripheral surface of the pouring tube portion 11, improving the sealing performance. At this time, by forming the first ring portion 27a, the second ring portion 27b, the first tube portion 11a, and the second tube portion 11b, the packaging container can be sealed at two points, a first sealing point 41 where the first ring portion 27a and the first tube portion 11a are in close contact with each other, and a second sealing point 42 where the second ring portion 27b and the second tube portion 11b are in close contact with each other.

[0026] At the same time, high pressure is applied from the inside to the outside to top surface 25 of cap 20 (white arrow in FIG. 3), which causes top surface 25 to bulge outward, and in reaction to this, stress is generated at the tip of inner ring 27 in a direction away from the inner circumferential surface of pouring tube portion 11 (black arrow in FIG. 3). At this time, the inner circumferential surface of inner ring 27 is pressed against protrusion 13, so that contact point 43 where protrusion 13 and the inner circumferential surface of inner ring 27 come into contact can seal the packaging container.

[0027] Furthermore, since the protruding portion 13 can restrict the inner ring 27 from moving away from the inner circumferential surface of the pouring / discharging cylindrical portion 11, the first ring portion 27a and the second ring portion 27b can be prevented from moving away from the first cylindrical portion 11a and the second cylindrical portion 11b, respectively, and loss of sealability at the first sealed portion 41 and the second sealed portion 42 can be prevented. Note that, in order to achieve both sealability at the first sealed portion 41 and the second sealed portion 42, it is preferable that the protruding portion 13 contacts the first ring portion 27a.

[0028] When the internal pressure of the packaging container decreases, high pressure is applied inward to the inner ring 27 and the top surface portion 25 of the cap 20 (white arrow in FIG. 4). The pressure applied to the inner ring 27 generates stress in the inner ring 27 in a direction away from the inner circumferential surface of the pouring tube portion 11, and in addition, the top surface portion 25 bulges inward due to the pressure applied to the top surface portion 25, so that in reaction, stress is further generated in the second ring portion 27b of the inner ring 27 in a direction away from the inner circumferential surface of the pouring tube portion 11 (black arrow in FIG. 4). At this time, the inner circumferential surface of the inner ring 27 is pressed against the protruding portion 13, so that the packaging container can be sealed by the contact portion 43 where the protruding portion 13 and the inner circumferential surface of the inner ring 27 come into contact with each other. In addition, since the protrusion 13 prevents the inner ring 27 from moving away from the inner surface of the pouring / dispensing tube portion 11, the first ring portion 27a and the second ring portion 27b are prevented from moving away from the first tube portion 11a and the second tube portion 11b, respectively, thereby preventing the sealing ability at the first sealing point 41 and the second sealing point 42 from being impaired.

[0029] <Effects> As described above, in the plug 100 according to this embodiment, the outer circumferential surface of the inner ring 27 and the inner circumferential surface of the pouring tube portion 11 are in close contact over the entire circumference, and the inner circumferential surface of the inner ring 27 and the protruding portion 13 are in close contact over the entire circumference. Therefore, the close contact between the inner circumferential surface of the pouring tube portion 11 and the outer circumferential surface of the inner ring 27 can be ensured without depending on changes in internal pressure.

[0030] Furthermore, the inner ring 27 has a first ring portion 27a and a second ring portion 27b, and the pouring / dispensing cylindrical portion 11 has a first cylindrical portion 11a and a second cylindrical portion 11b. This allows the packaging container to be sealed at two locations, a first sealing portion 41 where the first ring portion 27a and the first cylindrical portion 11a are in close contact with each other, and a second sealing portion 42 where the second ring portion 27b and the second cylindrical portion 11b are in close contact with each other, thereby further improving the sealing performance.

[0031] In addition, the inner surface of the top surface portion 25 and the tip of the pouring tube portion 11 are in close contact over the entire circumference, which can further improve the sealing performance.

[0032] In addition, the protruding portion 13 is formed with a rib 13c that makes line contact over the entire circumference with the inner circumferential surface of the inner ring 27 when the cap 20 is attached to the spout 10. This makes it easier for the cap 20 to follow the deformation of the spout 10, making it easier to suppress liquid leakage.

[0033] [Variations] The plug 100 according to the embodiment may be configured so that the rib 13c of the protruding portion 13 is omitted and the protruding portion 13 comes into surface contact with the first ring portion 27a as shown in Fig. 5. Even in this case, the protruding portion 13 can ensure the sealing performance of the first sealed portion 41, the second sealed portion 42, and the contact portion 43 without depending on the change in the internal pressure.

[0034] 6, a rib 27c protruding inward may be provided at the end of the inner ring 27. Even in this case, the protruding portion 13 can ensure the sealability of the first sealed point 41, the second sealed point 42, and the contact point 43 independently of changes in internal pressure.

[0035] 7, the second cylindrical portion 11b and the second ring portion 27b may be omitted, and an inner ring 27' may be used whose outer circumferential surface is a continuous curved surface. Even in this case, the protruding portion 13 ensures close contact between the inner circumferential surface of the pouring tube portion 11 and the outer circumferential surface of the inner ring 27' regardless of changes in internal pressure. In this case, in order to maintain the same level of sealing as the plug 100 in which the second cylindrical portion 11b and the second ring portion 27b are provided, it is preferable to make the amount of contact between the pouring tube portion 11 and the inner ring 27' larger than that of the plug 100. EXAMPLES

[0036] Examples of the present invention will now be described in detail.

[0037] (Example) A plug 100 according to the embodiment was produced (FIG. 1). At this time, the cap 20 was produced using block polypropylene (product name: PM870V, manufactured by Sunallomer Co., Ltd.), and the spout 10 was produced using LLDPE (product name: M2170, manufactured by Asahi Kasei Co., Ltd.). In addition, the contact amount at the contact point 43 where the protrusion 13 and the inner peripheral surface of the inner ring 27 contact was φ0.1 mm. The produced plug was attached to the container body, and a liquid container with a capacity of 1.8 L was produced.

[0038] (Comparative Example) A plug according to the comparative example was produced under the same conditions as in the example, except that protrusion 13 was not formed (FIG. 8). The produced plug was attached to a container body to produce a liquid container with a capacity of 1.8 L.

[0039] (Leakage evaluation after inverted drop) Five liquid containers each made in the Example and Comparative Example were prepared, filled with water at 70° C., and then cooled. All liquid containers were dropped upside down with the stoppers facing downward, and X-ray images of the stoppers were taken, and the obtained images were used to check for leakage of the contents.

[0040] In all five liquid containers according to the embodiment, the contents did not exceed the first sealed portion 41 where the first ring portion 27a and the first cylindrical portion 11a are in close contact with each other, and the sealability after being dropped upside down was excellent. In three of the five liquid containers according to the comparative example, the contents reached the area outside the inner ring on the top surface of the cap, and the remaining two had liquid leakage.

[0041] (Leak evaluation in an internal pressurized environment) Five liquid containers made in the example were prepared, filled with water, and then pressurized at 0.7 MPa for one second. Five liquid containers made in the comparative example were prepared, filled with water, and then pressurized at 0.3 MPa for one second. X-ray images of the stopper of each liquid container were taken, and the images obtained were used to check for leakage of the contents.

[0042] In the liquid containers according to the embodiment, none of the five containers had any leakage of the contents, and the containers had excellent sealing properties even in an internal pressurized environment. In the liquid containers according to the comparative example, four out of five containers had leakage of the liquid.

[0043] (Leak evaluation in an internal reduced pressure environment) Five liquid containers made in the example were prepared, filled with water, and then the pressure inside the containers was reduced to 0.07 MPa for 30 minutes. Five liquid containers made in the comparative example were prepared, filled with water, and then the pressure inside the containers was reduced to 0.05 MPa for 30 minutes. X-ray images of the mouth plugs of all liquid containers were taken, and the images obtained were used to check for the presence or absence of leakage of the contents.

[0044] In the liquid containers according to the embodiment, none of the five containers had any leakage of the contents, and the containers had excellent sealing properties even in an internal reduced pressure environment. In the liquid containers according to the comparative example, two out of the five containers had leakage of the liquid. [Industrial Applicability]

[0045] The plug according to the present invention can be used as a plug that is attached to a container body by welding or the like and that requires a tight seal. [Explanation of symbols]

[0046] 10: Spout 11: Pour cylinder part 11a: First cylinder part 11b: Second cylinder part 12: Flange part 13:Protrusion 20: Cap 25:Top section 26: Skirt section 27: Inner ring 27a: First ring section 27b: Second ring section 100: Plug

Claims

1. A plug comprising a spout and a cap attached to the spout, The cap is A top surface portion and A skirt portion extending perpendicularly from an edge of the top surface portion; A cylindrical inner ring is provided on the top surface portion and spaced from the skirt portion, The spout is A cylindrical pouring tube portion having a cylindrical shape; A flange portion connected to one end of the pouring tube portion; a protrusion that protrudes from the entire circumference of the inner circumferential surface of the pouring tube portion and contacts the entire circumference of the inner circumferential surface of the inner ring of the cap attached to the spout.

2. The inner ring includes, in order from the flange portion side, A first ring portion; A second ring portion having an outer diameter larger than that of the first ring portion, The pouring tube portion includes, in order from the tip side, a second cylindrical portion into which the second ring portion is inserted; a first cylindrical portion into which the first ring portion is inserted; 2. The plug according to claim 1, wherein, when the cap is attached to the spout, an outer peripheral surface of the first ring portion and an inner peripheral surface of the first cylindrical portion are in close contact with each other around the entire circumference, and an outer peripheral surface of the second ring portion and an inner peripheral surface of the second cylindrical portion are in close contact with each other around the entire circumference.

3. The plug according to claim 1 , wherein when the cap is attached to the spout, the protrusion and the inner circumferential surface of the inner ring are in line contact over the entire circumference.

4. The plug according to claim 1 , wherein when the cap is attached to the spout, the inner surface of the top surface portion and the tip end of the cylindrical pouring portion are in close contact with each other over the entire circumference.

5. A container body; A packaging container comprising the plug according to any one of claims 1 to 4 attached to the container body.

Images