Plug and packaging container equipped with the same

Abstract

To provide a plug hard to lose sealability and difficult for a content to remain in the plug after pouring-out of the content even when the inner pressure of a packaging container changes, and the packaging container equipped with the same.SOLUTION: This plug is constructed such that a spout is provided with a pouring cylindrical part having a cylindrical shape, a flange connected to one end of the pouring cylindrical part, and a projected part which projects from the entire circumference of the inner peripheral surface of the pouring cylindrical part and comes into contact with the inner peripheral surface of an inner ring of a cap attached to the spout, the projected part is provided with a cylindrical small wall part provided away from the inner peripheral surface of the pouring cylindrical part, an annular connection part which connects the inner peripheral surface of the pouring cylindrical part and the small wall part, and an annular rib which is formed over the end of the small wall part on the other end side of the pouring cylindrical part and in contact with the inner peripheral surface of the inner ring, and 10 or less slits extending from the end of the rib on the other end side of the pouring cylindrical part to a connection portion with the connection part in the small wall part are formed in the rib and the small wall part.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).

[0004] 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. [Prior art documents] [Patent documents]

[0005] [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]

[0006] One possible means for solving the problem of poor adhesion between the inner circumferential surface of the spout portion and the inner ring is to provide a protrusion 113 that presses inner ring 127 against the inner circumferential surface of spout portion 111, as shown in FIG.

[0007] Considering the adhesion between the inner peripheral surface of the spout 111 and the inner ring 127, it is preferable that the protrusion 113 is formed over the entire circumference of the inner peripheral surface of the spout 111. However, by providing such a protrusion 113, as shown in Fig. 8(b), a pocket-like space S' is formed between the inner peripheral surface of the spout 111 and the protrusion 113, so there is a concern that when the packaging container is inverted after the contents are poured out, the contents that should have returned to the container body may be captured and remain in the space S'. Furthermore, since the remaining contents may leak from the stopper or deteriorate, it is undesirable for the contents to remain in the space S'.

[0008] The present invention aims to provide a plug whose sealing ability is not easily impaired even when the internal pressure of the packaging container changes, and in which the contents are not easily left behind in the plug after the contents are poured out, and a packaging container equipped with the plug. [Means for solving the problem]

[0009] The plug according to the present invention comprises a spout and a cap attached to the spout. 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. 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 peripheral surface of the pouring tubular portion and contacting the inner peripheral surface of the inner ring of the cap attached to the spout. The protruding portion comprises a cylindrical small wall portion provided at a distance from the inner peripheral surface of the pouring tubular portion, an annular connecting portion connecting the inner peripheral surface of the pouring tubular portion and the small wall portion, and an annular rib formed at an end of the small wall portion on the other end side of the pouring tubular portion and contacting the inner peripheral surface of the inner ring. The rib and the small wall portion have 10 or less slits formed therein, extending from the end of the rib on the other end side of the pouring tubular portion to a connection point with the connecting portion in the small wall portion.

[0010] 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

[0011] According to the present invention, it is possible to provide a plug whose sealing ability is not easily impaired even when the internal pressure of the packaging container changes, and in which the contents are not easily left behind in the plug after the contents are poured out, and a packaging container equipped with the plug. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a plug according to an embodiment. [Diagram 2] End view corresponding to A-A' in FIG. 1 [Diagram 3] End view corresponding to the thin dashed line in Figure 2 [Figure 4] Partial end view near the protruding portion of the spout [Diagram 5] FIG. 1 is an end view showing the state of the plug when the internal pressure of the packaging container increases [Figure 6] FIG. 1 is an end view showing the state of the plug when the internal pressure of the packaging container increases [Figure 7]FIG. 1 is an end view showing the state of the plug when the internal pressure of the packaging container is reduced; [Figure 8] A diagram explaining the problems caused by protrusions [Figure 9] 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

[0013] [Embodiment] Fig. 1 is a vertical end view showing a schematic configuration of a plug according to an embodiment. Fig. 2 is an end view corresponding to A-A' in Fig. 1. Fig. 1 shows a state before opening the plug, and in Fig. 1(c) and Fig. 2, the cap 20 is omitted.

[0014] <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.

[0015] (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, a cylindrical skirt portion 26 that extends vertically from the edge of the top surface portion 25, and an inner ring 27 formed on the top surface portion 25 at a position spaced apart from the skirt portion 26. A female thread 4b that screws into a male thread 4a formed on the spout 10 is formed on the inner circumferential surface of the skirt portion 26. The inner ring 27 is in close contact with the inner circumferential surface of the pouring tube portion 11.

[0016] Inner ring 27 is a cylindrical member provided on top surface 25 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.

[0017] (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.

[0018] 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.

[0019] 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.

[0020] The protruding portion 13 includes a cylindrical small wall portion 13a spaced apart from the inner peripheral surface of the tubular pouring portion 11, a connecting portion 13b connecting the inner peripheral surface of the tubular pouring portion 11 and the small wall portion 13a, and an annular rib 13c formed on the outer peripheral surface (the surface facing the inner peripheral surface of the tubular pouring portion 11) of the end portion of the small wall portion 13a on the other end side of the tubular pouring portion 11 (the end portion of the small wall portion 13a opposite the flange portion 12). When the cap 20 is attached to the spout 10, a first ring portion 27a of an inner ring 27 of the cap 20 is inserted between the inner peripheral surface of the first tubular portion 11a of the spout 10 and the rib 13c, and at this time the rib 13c is in line contact with the inner peripheral surface of the inner ring 27. If cap 20 is made of a hard material compared to spout 10, it is difficult for cap 20 to follow the sudden deformation of spout 10 that occurs when a packaging container is dropped, for example. However, the formation of rib 13c makes it easier for cap 20 to follow the deformation of spout 10, thereby preventing liquid leakage.

[0021] A slit 51 is formed in the rib 13c and the small wall portion 13a, extending from an end portion of the rib 13c on the other end side of the pouring tube portion 11 (an end portion of the rib 13c opposite the flange portion 12) to a connection portion of the small wall portion 13a with the connection portion 13b. By forming the slit 51, the contents remaining in the space S partitioned by the inner circumferential surface of the pouring tube portion 11, the small wall portion 13a, and the connection portion 13b can be discharged into the container body. Therefore, the contents can be prevented from remaining in the space S.

[0022] Considering the efficiency of discharging the contents in the space S, it is preferable to provide a plurality of slits 51 intermittently in the circumferential direction as shown in FIG. 2. The more the number of slits 51 is and the wider the width is, the higher the efficiency of discharging the contents in the space S is. However, on the other hand, the rigidity of the protruding portion 13 is reduced, the force with which the protruding portion 13 presses the inner ring 27 is weakened, and the sealing performance is deteriorated. Therefore, it is preferable that the number of slits 51 is 10 or less, and the width of the slits 51 is 0.5 mm or more and 3.0 mm or less. When the viscosity of the contents is low, it is preferable to design the number of slits 51 to be small and the width to be narrow. On the other hand, when the viscosity of the contents is high, it is necessary to design the width of the slits 51 to be wide, so it is preferable to design the number of slits 51 to be small. In addition, considering the efficiency of discharging the contents in the space S and ensuring the rigidity of the protruding portion 13, it is more preferable that the number of slits 51 is 3 or more and 6 or less.

[0023] Fig. 3 is an end view corresponding to the thin dashed line in Fig. 2. As shown in Fig. 3, an exposed surface F1 of the connecting portion 13b exposed on one end side of the pouring tube portion 11 may be provided with a slope L whose height decreases toward the slit 51. By providing the slope L, the contents remaining in the space S can be efficiently flowed into the slit 51, so that the contents can be more reliably prevented from remaining in the space S. The slope L may be configured such that the contents flow into one slit 51 from only one direction as shown in Fig. 3(a), or may be configured such that the contents flow into one slit 51 from two directions as shown in Fig. 3(b).

[0024] Fig. 4 is a partial end view in the vicinity of the protruding portion of the spout. As shown in Fig. 4, the exposed surface F1 may be provided with a slope that decreases in height from the pouring tube portion 11 side toward the small wall portion 13a. By providing a slope, the contents in the space S can be efficiently discharged. In consideration of more efficient discharge of the contents, the slope angle θ2 (the angle between the horizontal plane and the exposed surface F1) is preferably 20° or more. In addition, the slope angle θ2 needs to be suppressed to an extent that does not interfere with the protruding portion 13 and the inner ring 27, and is, for example, 45° or less.

[0025] Moreover, it is preferable that face F2 on one end side of the pouring tube portion 11 in the connecting portion 13b is a curved surface whose inner diameter narrows toward the other end side (tip side) of the pouring tube portion 11 (FIG. 4). This makes it easier for the contents to flow toward the tip of the pouring tube portion 11 during pouring, compared to when face F2 is formed horizontally, thereby improving pouring performance.

[0026] It is preferable that the inner peripheral surface of the small wall portion 13a is formed with continuous unevenness 33 over the entire circumference in the circumferential direction (FIG. 2). By providing the unevenness 33, it is possible to improve the liquid return property of the contents remaining at the tip of the pouring tube portion 11.

[0027] In order to improve liquid drainage, the inner peripheral surface of rib 13c preferably has an inclination such that the inner diameter increases toward the other end (tip side) of pouring tube portion 11 (FIG. 1(c)). In consideration of liquid drainage, the inclination angle θ1 of the inner peripheral surface of rib 13c is preferably 75° or less. In consideration of the removal of spout 10 from the mold, the inclination angle θ1 is preferably 45° or more. In this case, the inclination angle θ1 of the inner peripheral surface of rib 13c is the angle between the inner peripheral surface of rib 13c and a plane perpendicular to the central axis of pouring tube portion 11. The molding of spout 10 using a mold will be described later.

[0028] When cap 20 is attached to spout 10, first ring portion 27a of inner ring 27 is inserted between the inner circumferential surface of first cylindrical portion 11a of spout 10 and rib 13c, and at this time, in order to prevent first ring portion 27a and connecting portion 13b from coming into contact and becoming deformed, it is preferable that the tip of first ring portion 27a and connecting portion 13b are spaced apart by about 0.2 mm to 0.3 mm. Furthermore, by providing a contact ring (not shown) around the entire circumference of the tip of pouring cylindrical portion 11, it is possible to make it even more difficult for first ring portion 27a and connecting portion 13b to come into contact with each other.

[0029] 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.

[0030] 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.

[0031] <How to mold the spout> 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.

[0032] 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.

[0033] <Function of the protrusion> 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 plug, causing the sealing property to be impaired. The plug 100 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 plug 100 when the internal pressure rises and when the internal pressure decreases will be described. Figures 5 and 6 are end views showing the state of the plug when the internal pressure of the packaging container rises, and Figure 7 is an end view showing the state of the plug 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.

[0034] 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. 5). 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.

[0035] 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. 6), 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. 6). At this time, the inner circumferential surface of inner ring 27 is pressed against protruding portion 13, so that contact point 43 where protruding portion 13 and the inner circumferential surface of inner ring 27 come into contact can seal the packaging container.

[0036] 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.

[0037] 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. 7). 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. 7). 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.

[0038] <Spout design> As described above, the sealing of the packaging container can be achieved by ensuring close contact at either the first sealing point 41, where the first ring portion 27a and the first tubular portion 11a are in close contact with each other, or the second sealing point 42, where the second ring portion 27b and the second tubular portion 11b are in close contact with each other.

[0039] And, since the contact between the protrusion 13 and the inner peripheral surface of the inner ring 27 at the contact point 43 plays a role in assisting the adhesion of the first sealed point 41 and the second sealed point 42, the adhesion between the protrusion 13 and the inner ring 27 at the contact point 43 is important. Since the adhesion at the contact point 43 is affected by the viscosity of the contents, the elastic modulus of the resin used in the spout 10, and the amount of the contents, it is necessary to change the design of the plug 100 taking these factors into consideration. Specific examples will be described below.

[0040] (Designed according to the viscosity of the contents) When the internal pressure of the packaging container rises instantaneously due to the impact of being dropped, pressure is applied to small wall portion 13a through slit 51, which acts in a direction that moves protrusion 13 away from inner ring 27, impairing the sealing performance. In particular, when the viscosity of the contents is low (in the case of a thin liquid), the pressure applied to small wall portion 13a through slit 51 is likely to be large compared to when the viscosity is high. Therefore, when the viscosity of the contents is low, it is preferable to design the occupancy rate of slit 51 in protrusion 13 to be small.

[0041] (Designed according to the elasticity of the spout) If the elastic modulus of the resin used for spout 10 is low, the force with which rib 13c presses inner ring 27 toward pouring tube portion 11 will also be small, resulting in poor sealing. Therefore, if the elastic modulus of spout 10 is low, it is necessary to thicken protruding portion 13 to increase its rigidity or to increase the amount of contact between rib 13c and inner ring 27.

[0042] (Designed with the amount of contents in mind) The greater the amount of contents, the more significant the rise in internal pressure that occurs when the packaging container is dropped, and the greater the pressure applied to the small wall portion 13a through the slit 51, which tends to hinder the close contact between the protruding portion 13 and the inner ring 27. Therefore, it is necessary to optimize the design according to the viscosity of the contents and the elastic modulus of the spout 10, taking into consideration the amount of contents.

[0043] <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 is in close contact with the protruding portion 13. 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.

[0044] 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.

[0045] 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.

[0046] Furthermore, protrusion 13 is formed with rib 13c that comes into line contact with the inner circumferential surface of inner ring 27 when cap 20 is attached to spout 10. This allows cap 20 to easily follow the deformation of spout 10, making it easier to suppress liquid leakage.

[0047] A slit 51 is formed in the rib 13c and the small wall portion 13a. This allows the contents remaining in the space S defined by the inner circumferential surface of the pouring tube portion 11, the small wall portion 13a, and the connecting portion 13b to be discharged into the container body 1.

[0048] Furthermore, the number of slits 51 is equal to or less than 10. This makes it possible to ensure the rigidity of spout 10 while forming slits 51, and to suppress a decrease in sealing performance.

[0049] Moreover, the width of the slit 51 is 0.5 mm or more and 3.0 mm or less, which makes it possible to ensure the efficiency of discharging the contents in the space S and the rigidity of the protruding portion 13.

[0050] Moreover, the number of slits 51 is equal to or greater than 3 and equal to or less than 6. This makes it possible to more suitably ensure the efficiency of discharging the contents in the space S and the rigidity of the protruding portion 13.

[0051] Moreover, the exposed surface F1 of the connecting portion 13b is provided with a slope L whose height decreases toward the slit 51. This allows the contents remaining in the space S to flow efficiently into the slit 51, so that the contents can be more reliably prevented from remaining in the space S.

[0052] Moreover, the exposed surface F1 of the connecting portion 13b is provided with a slope that decreases in height from the pouring tube portion 11 side toward the small wall portion 13a. This allows the content in the space S to be efficiently discharged from the slit 51.

[0053] Furthermore, it is preferable that surface F2 of connecting portion 13b on one end side of pouring tube portion 11 is a curved surface whose inner diameter narrows toward the other end side of pouring tube portion 11. This improves the pouring property of the content.

[0054] In addition, it is preferable that the inner peripheral surface of the small wall portion 13a is formed with continuous unevenness 33 over the entire circumference in the circumferential direction. This can improve the liquid return property of the contents remaining at the tip of the pouring tube portion 11.

[0055] In order to improve the liquid drainage, the inner peripheral surface of the rib 13c is an inverse tapered surface whose inner diameter increases toward the tip of the pouring tube portion 11, and the inclination angle θ1 of the inner peripheral surface of the rib 13c is preferably 45° or more and 75° or less. This improves the liquid drainage and the removability of the spout 10 from the mold. EXAMPLES

[0056] Examples of the present invention will now be described in detail.

[0057] Example 1 A plug 100 according to the embodiment was produced (FIG. 1). At this time, the cap 20 was produced using block polypropylene (MFR: 17g / 10min, product name: PM870V, manufactured by Sunallomer Co., Ltd.), and the spout 10 was produced using LLDPE (MFR: 7g / 10min, product name: M2170, manufactured by Asahi Kasei Co., Ltd.). The flexural modulus of the cap 20 was 1240MPa, and the flexural modulus of the spout 10 was 140MPa. The number of slits 51 was 3, the width of the slits 51 was 1mm, and the contact amount at the contact point 43 where the protrusion 13 and the inner peripheral surface of the inner ring 27 contacted was φ0.1mm. The produced plug 100 was attached to the container body 1, and a liquid container with a capacity of 1.8L was produced.

[0058] Example 2 A plug 100 according to Example 2 was produced under the same conditions as in Example 1, except that the number of slits 51 was 6 and the width of slits 51 was 0.8 mm. Thereafter, a liquid container was produced in the same manner as in Example 1.

[0059] Example 3 A plug 100 according to Example 3 was produced under the same conditions as in Example 1, except that the number of slits 51 was 10 and the width of the slits 51 was 0.8 mm. Thereafter, a liquid container was produced in the same manner as in Example 1.

[0060] Example 4 A plug 100 according to Example 4 was produced under the same conditions as in Example 1, except that the number of slits 51 was 4 and the width of the slits 51 was 3.0 mm. Thereafter, a liquid container was produced in the same manner as in Example 1.

[0061] Comparative Example 1 A plug according to the comparative example was produced under the same conditions as in the example, except that the protruding portion 13 was not formed (FIG. 9). Thereafter, a liquid container was produced in the same manner as in the first example.

[0062] (Evaluation of remaining contents in space S / low viscosity contents) Five liquid containers each made in the Example and Comparative Example were prepared and filled with alcohol (low viscosity). 30cc of alcohol was poured out of each liquid container 20 times. At this time, the lid was opened and closed once every three pours. X-ray images of the stopper were taken, and the presence or absence of the contents remaining in the space S was confirmed using the obtained images.

[0063] In the evaluation of the presence or absence of remaining liquid in the low-viscosity space S described above, those in which no remaining liquid was found in any of the five liquid containers were rated as ◎, those in which two or less small speck-like remaining liquids were found were rated as ◯, those in which three to four partial remaining liquids were found were rated as △, and those in which puddles of remaining liquid were found in any of the five liquid containers were rated as ×.

[0064] (Leak evaluation in an internal pressurized environment / 0.5MPa) Five liquid containers each made in the Example and Comparative Example were prepared, filled with water, and then pressurized at 0.5 MPa for 1.0 second. X-ray images of the stoppers of all liquid containers were taken, and the images obtained were used to check for leakage of the contents.

[0065] (Leakage evaluation after inverted drop) Five liquid containers each from the examples and comparative examples 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 images obtained were used to check for leakage of the contents.

[0066] In the various leakage evaluations described above, if there was leakage in all five pieces (if the contents went beyond the contact point between the inner surface of the top surface 25 and the tip of the pouring tube 11), it was evaluated as ×; if the contents did not go beyond the contact point between the inner surface of the top surface 25 and the tip of the pouring tube 11 in all five pieces, it was evaluated as △; if the contents did not go beyond the second sealed point 42 in all five pieces, it was evaluated as ◯; and if the contents did not go beyond the first sealed point 41 in all five pieces, it was evaluated as ◎.

[0067] The evaluation results are shown in Table 1. For the overall evaluation of leakage, cases in which there was an × in the remaining presence / absence evaluation or leakage evaluation were evaluated as ×, cases in which there was an ○ in the remaining presence / absence evaluation or there was a △ in the leakage evaluation were evaluated as △, and cases other than that were evaluated as 〇.

[0068] [Table 1]

[0069] In Example 1, little content remained in the space S regardless of the viscosity of the content, and no liquid leakage beyond the first sealed portion 41 occurred.

[0070] In Example 2, no liquid leakage occurred under any of the conditions, but after being dropped upside down, the contents exceeded first sealed portion 41 in some cases, resulting in a lower evaluation than Example 1. This is because the occupancy rate of slit 51 with respect to protruding portion 13 increased compared to Example 1, resulting in a lower rigidity of spout 10 than in Example 1.

[0071] In Example 3, the width of the slits 51 was the same as in Example 2, but the number of slits 51 was increased, further reducing the rigidity of the spout 10. Therefore, in the liquid leakage evaluation, the contents exceeded the second sealed portion 42 in some cases.

[0072] In Example 4, the number of slits 51 was smaller than that in Example 3, but the width of the slits 51 was wider. Therefore, the rigidity of the spout 10 was similar to that in Example 3, and the results of the leakage evaluation were also similar to those in Example 3.

[0073] In Comparative Example 1, since the protrusion 13 was not formed, liquid leakage occurred even when the pressure was 0.5 MPa.

[0074] Next, the viscosity of the contents was changed to a higher one and an evaluation was performed to see if any remained in the space S.

[0075] (Evaluation of remaining contents in space S / medium viscosity contents) Five liquid containers each made in the Example and Comparative Example were prepared and filled with soup (medium viscosity) made of soy sauce with added slight sugar. 30cc of soup was poured 20 times for all liquid containers. At this time, the lid was opened and closed once every three pours. X-ray images of the spout were taken, and the presence or absence of the contents remaining in the space S was confirmed using the obtained images.

[0076] The evaluation results are shown in Table 2. [Table 2]

[0077] In Example 1, a very small amount of content was found remaining in the space S, but this was not enough to affect use.

[0078] In Examples 2 and 3, some content may remain in the space S. This is because the width of each slit 51 is narrower than that in Example 1.

[0079] In Example 4, the number of slits 51 was smaller than in Example 3, but the width of the slits 51 was as wide as 3.0 mm, so that the content remaining in the space S could be suppressed.

[0080] Next, the internal pressurized environment was set to 0.7 MPa and a leakage evaluation was performed.

[0081] (Leak evaluation in an internal pressurized environment / 0.7MPa) Five liquid containers each made in the Example and Comparative Example were prepared, filled with water, and then pressurized at 0.7 MPa for 1.0 seconds. X-ray images of the stoppers of all liquid containers were taken, and the images obtained were used to check for leakage of the contents.

[0082] The evaluation results are shown in Table 3. [Table 3]

[0083] In Example 1, no liquid leakage beyond the first sealed portion 41 occurred.

[0084] In Example 2, some of the contents exceeded the first sealed portion 41, and it was rated lower than Example 1. This is because the occupancy rate of the slit 51 with respect to the protruding portion 13 increased compared to Example 1, and therefore the rigidity of the spout 10 was lower than that of Example 1.

[0085] In Example 3, the width of slits 51 was the same as in Example 2, but the number of slits 51 was increased, further reducing the rigidity of spout 10. As a result, the contents exceeded second sealed portion 42 in some cases.

[0086] In Example 4, the number of slits 51 was smaller than that in Example 3, but the width of the slits 51 was wider. Therefore, the rigidity of the spout 10 was similar to that in Example 3, and the results of the leakage evaluation were also similar to those in Example 3.

[0087] In Comparative Example 1, since the protrusion 13 was not formed, liquid leakage occurred. [Industrial Applicability]

[0088] 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]

[0089] 1: Container body 10: Spout 11: Pour cylinder part 12: Flange part 13:Protrusion 13a: Small wall part 13b: Connection 13c: Rib 20: Cap 25:Top section 26: Skirt section 27: Inner ring 33: Unevenness 51: Slit 100: Cap 113:Protrusion 127: Inner ring F1: Exposed surface F2 :Face L: Inclined θ1: Tilt angle

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 protruding from the entire circumference of the inner circumferential surface of the pouring tube portion and contacting the inner circumferential surface of the inner ring of the cap attached to the spout, The protrusion is A cylindrical small wall portion provided at a distance from an inner circumferential surface of the pouring tube portion; an annular connection portion that connects an inner circumferential surface of the pouring tube portion and the small wall portion; an annular rib formed at an end portion of the small wall portion on the other end side of the pouring tube portion and in contact with an inner circumferential surface of the inner ring; The plug has ten or less slits formed in the rib and the small wall portion, the slits extending from an end of the rib on the other end side of the pouring tube portion to a connection point of the small wall portion with the connection portion.

2. 2. The plug according to claim 1, wherein the width of the slit in the circumferential direction is 0.5 mm or more and 3.0 mm or less.

3. 2. The plug according to claim 1, wherein the number of the slits is 3 or more and 6 or less.

4. The plug according to claim 1 , wherein an exposed surface of the connecting portion that is exposed on the one end side of the pouring tube portion is provided with a slope that decreases in height toward the slit.

5. The plug according to claim 1 , wherein an exposed surface of the connecting portion that is exposed on the one end side of the cylindrical pouring portion is provided with a slope that decreases in height from the cylindrical pouring portion side toward the small wall portion.

6. The plug according to claim 1 , wherein a surface of said one end side of said connecting portion is a curved surface whose inner diameter narrows toward said other end side of said cylindrical pouring portion.

7. 2. The plug according to claim 1, wherein the inner circumferential surface of the small wall portion has continuous projections and recesses formed all around the circumferential surface.

8. 2. The plug according to claim 1, wherein an inner peripheral surface of the rib has an inclination such that an inner diameter increases toward the other end of the cylindrical pouring portion, and an inclination angle of the inner peripheral surface of the rib is equal to or greater than 45° and equal to or less than 75°.

9. A container body; A packaging container comprising: the plug according to any one of claims 1 to 8 attached to the container body.

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