Stopper and packaging container

Abstract

To improve airtightness. [Solution] The spout comprises a spout and a cap that can be attached to the spout. The spout has a cylindrical side wall, a flange provided on one end of the side wall, and a projection provided on the inner circumferential surface of the side wall. The cap has a top plate, a circumferential wall connected to the outer edge of the top plate, and a cylindrical inner ring connected to the inside of the outer edge of the top plate. The projection of the spout is formed to contact the inner circumferential surface of the inner ring when the cap is attached to the spout. When the outer diameter A and inner diameter B in the state when the cap is not attached to the spout are defined as follows: Outer diameter A: outer diameter of the part of the projection that contacts the inner circumferential surface of the inner ring, and Inner diameter B: inner diameter of the tip of the inner ring, the axle amount (AB) obtained by subtracting the inner diameter B from the outer diameter A is -0.15 mm to 0.02 mm.

Description

Technical Field

[0001] The present disclosure relates to a stopper and a packaging container.

Background Art

[0002] Patent Document 1 discloses a stopper including a hollow spout having a thread formed on its outer peripheral surface, a wall portion having a thread formed on its inner peripheral surface, and a top surface closing one end of the wall portion, and a cap having an open other end.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a stopper and a packaging container useful for improving sealing performance.

Means for Solving the Problems

[0005] [1] A spout and a cap that can be attached to the spout, wherein the spout has a cylindrical side wall, a flange provided on one end of the side wall, and a projection provided on the inner circumferential surface of the side wall, the cap has a top plate, a circumferential wall connected to the outer edge of the top plate, and a cylindrical inner ring connected inward from the outer edge of the top plate, the projection of the spout is formed to contact the inner circumferential surface of the inner ring when the cap is attached to the spout, and when the outer diameter A and inner diameter B in a state where the cap is not attached to the spout are defined as follows: outer diameter A: outer diameter of the portion of the projection that contacts the inner circumferential surface of the inner ring, and inner diameter B: inner diameter of the tip of the inner ring, the axle amount (AB) obtained by subtracting the inner diameter B from the outer diameter A is -0.15 mm to 0.02 mm.

[0006] [2] The plug according to [1], wherein a portion of the inner circumferential surface of the inner ring, including the tip portion, is formed to extend along the central axis of the plug.

[0007] [3] The spout according to [1] or [2] above, wherein the inner ring includes a first inner portion and a second inner portion having a larger outer diameter than the first inner portion, the second inner portion and the first inner portion are arranged in this order from the top plate, the side wall of the spout includes a first cylindrical portion corresponding to the first inner portion and a second cylindrical portion corresponding to the second inner portion, and when the cap is attached to the spout, the outer circumferential surface of the first inner portion contacts the inner circumferential surface of the first cylindrical portion and the outer circumferential surface of the second inner portion contacts the inner circumferential surface of the second cylindrical portion.

[0008] [4] The spout according to any one of [1] to [3] above, wherein when the cap is attached to the spout, the portion of the protrusion contacts the inner surface of the inner ring around the entire circumference of the central axis of the spout.

[0009] [5] The spout according to any one of [1] to [4] above, wherein when the cap is attached to the spout, the tip of the side wall contacts the underside of the top plate around the entire circumference of the central axis of the spout.

[0010] [6] A packaging container comprising a spout as described in any one of [1] to [5] above, and a container body to which the spout is attached. [Effects of the Invention]

[0011] According to this disclosure, a spout and packaging container useful for improving airtightness are provided. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a perspective view illustrating a packaging container equipped with a spout. [Figure 2] Figure 2 is a side view illustrating an unopened cap. [Figure 3] Figure 3 is a cross-sectional view illustrating an unopened cap. [Figure 4] Figure 4(a) is a cross-sectional view illustrating the cap. Figure 4(b) is a cross-sectional view illustrating the spout. [Figure 5] Figure 5 is an enlarged view of a portion of the cross-section shown in Figure 3. [Figure 6] Figures 6(a), 6(b), and 6(c) are schematic diagrams illustrating the behavior of the valve in response to pressure changes. [Figure 7] Figures 7(a), 7(b), and 7(c) are schematic diagrams illustrating the method for verifying airtightness. [Figure 8] Figure 8 is a graph illustrating the results of the airtightness verification. [Figure 9] Figures 9(a), 9(b), and 9(c) are images of the cross-section of the mouthpiece. [Modes for carrying out the invention]

[0013] Hereinafter, an embodiment will be described with reference to the drawings. In the description, elements having the same element or the same function are denoted by the same reference numerals, and redundant descriptions are omitted. The dimensional ratios of each element are not limited to the ratios shown in the drawings. In some of the drawings, an orthogonal coordinate system defined by the X-axis, Y-axis, and Z-axis is shown.

[0014] [Packaging container] FIG. 1 shows a perspective view of a packaging container according to an embodiment. The packaging container 1 is a container for storing contents. The contents stored in the packaging container 1 may be in a liquid state, and specific examples thereof include alcoholic beverages, drinks, and seasonings. The packaging container 1 includes a container body 2 and a stopper 4. The container body 2 is a main body portion for storing contents such as liquid. Examples of the material of the container body 2 include paper, resin, and glass. The material of the container body 2 may be a laminate of paper and resin. A stopper 4 is fixed to the container body 2.

[0015] (Stopper) The stopper 4 is a member for forming a pouring outlet for pouring out the contents from the packaging container 1 (container body 2). The stopper 4 includes a cap 10 and a spout 30. The cap 10 is a member that can be attached to the spout 30 and has a function of closing the pouring outlet formed by the spout 30. Hereinafter, the state in which the spout 30 is attached to the cap 10 is referred to as the "attached state", and the state in which the cap 10 is not attached to the spout 30 is referred to as the "non-attached state".

[0016] FIG. 2 shows a side view of the stopper 4 in the attached state. FIG. 3 shows a longitudinal section of the stopper 4 shown in FIG. 2. FIG. 4(a) shows a longitudinal section of the cap 10 in the non-attached state, and FIG. 4(b) shows a longitudinal section of the spout 30 in the non-attached state. Note that the non-attached state includes the state before assembling the cap 10 and the spout 30 after manufacturing them, and the state after removing the cap 10 from the spout 30 after assembling.

[0017] Both the cap 10 and the spout 30 may be made of resin. The cap 10 and the spout 30 may both be formed using a thermoplastic resin such as PP (polypropylene) or PE (polyethylene). Also, depending on the contents, a resin with high resistance to the contents (for example, trade name: Petrothene 360, manufactured by Tosoh Corporation) may be used as the material of the spout 30. The cap 10 may be formed of a material harder than the material constituting the spout 30. The cap 10 may be formed of a material having higher rigidity than the material constituting the spout 30. The cap 10 is, for example, made of polypropylene resin. The spout 30 is, in one example, made of low-density polyethylene resin, and among them, it may be made of linear low-density polyethylene resin.

[0018] In the present disclosure, based on the central axis Ax of the stopper 4 in the attached state (see FIG. 3), the direction approaching the central axis Ax is defined as "in" and "inner side", and the direction away from the central axis Ax is defined as "out" and "outer side". For convenience of explanation, the direction along the central axis Ax is defined as the "vertical direction". Depending on the posture of the packaging container 1 provided with the stopper 4 or the posture of the stopper 4 before being fixed to the container body 2, the vertical direction is not necessarily the vertical direction. Also, among the vertical directions, the direction (orientation) in which the cap 10 moves with respect to the spout 30 when transitioning from the attached state to the non-attached state is defined as "up", and the direction (orientation) in which the cap 10 moves with respect to the spout 30 when transitioning from the non-attached state to the attached state is defined as "down". In addition, even in the description of the cap 10 and the spout 30 in the non-attached state, these terms are used based on the state after assembly of the cap 10 and the spout 30.

[0019] As shown in FIGS. 2, FIGS. 3, and FIGS. 4(a), the cap 10 has a top plate 12, a peripheral wall 14, an internal thread 15, and an inner ring 16.

[0020] The top plate 12 is a disc-shaped portion. A tapered portion 18 may be formed on the outer edge of the top plate 12 (more specifically, on the outer edge of the upper surface of the top plate 12). The peripheral wall 14 has a cylindrical shape and extends downward from the tapered portion 18. The upper end of the peripheral wall 14 is connected to the outer edge of the top plate 12. Multiple protrusions 22 are formed on the outer surface of the peripheral wall 14. The multiple protrusions 22 are arranged in the circumferential direction around the central axis Ax (hereinafter simply referred to as the "circumferential direction"). The multiple protrusions 22 are formed to improve the operability of the cap 10.

[0021] The longitudinal section shown in Figure 3 represents a cross-section obtained by cutting the spout 4 with an arbitrary plane containing the central axis Ax. In the longitudinal section, the peripheral wall 14 extends along the vertical direction (the Z-axis in the figure). The central axis Ax of the spout 4 (the central axis of the cap 10) is a hypothetical axis that passes through the center of the top plate 12 and extends perpendicular to the flat surface of the top surface of the top plate 12.

[0022] The internal thread 15 is provided on the inner surface of the peripheral wall 14. The inner ring 16 has a cylindrical shape and extends downward from the inner surface (bottom surface) of the top plate 12. The inner ring 16 is positioned inside the peripheral wall 14, with a space between it and the peripheral wall 14. The upper end of the inner ring 16 is connected inside the outer edge of the top plate 12. The shortest distance between the inner ring 16 and the central axis Ax is smaller than the shortest distance between the peripheral wall 14 and the central axis Ax.

[0023] The peripheral wall 14 may include a base portion 24, as shown in Figure 2. The base portion 24 includes the lower end of the peripheral wall 14 and is the portion where the multiple protrusions 22 are not formed. The cap 10 may have a band portion 26. The band portion 26 has a cylindrical shape, and the outer diameter of the band portion 26 is approximately the same as the outer diameter of the peripheral wall 14. The function and role of the band portion 26 will be described later.

[0024] As shown in Figures 3 and 4(b), the spout 30 has a side wall 32, an external thread 33, and a flange 34. The side wall 32 has a cylindrical shape. The side wall 32 extends vertically in a longitudinal section. The inner diameter of the side wall 32 is smaller than the inner diameter of the circumferential wall 14 of the cap 10. That is, the shortest distance between the side wall 32 and the central axis Ax is smaller than the shortest distance between the circumferential wall 14 and the central axis Ax. In the installed state, a portion of the side wall 32, including the upper end, is inserted into the space between the circumferential wall 14 and the inner ring 16.

[0025] The external thread 33 is provided on the outer circumferential surface of the side wall 32. For example, the external thread 33 is provided on the outer circumferential surface of the upper half of the side wall 32. When installed, the external thread 33 is formed to screw into the internal thread 15 provided on the inner circumferential surface of the side wall 14 of the cap 10. When installed, the side wall 32 is in contact (tightly attached) with the inner ring 16 and the top plate 12 at multiple locations. This prevents the contents from leaking (for example, liquid leakage) from between the spout 30 and the cap 10.

[0026] The flange 34 is provided on one end of the side wall 32. The flange 34 is connected to the lower end of the side wall 32 and extends outward from the side wall 32. The flange 34 is formed in an annular shape. The flange 34 is the joint where the spout 4 (spout 30) is fixed to the container body 2. The packaging material of the container body 2 may be joined to at least a portion of the upper surface of the flange 34. The joining of the packaging material of the container body 2 and the upper surface of the flange 34 may be performed by ultrasonic welding or adhesive bonding.

[0027] The spout 30 may have a notch 36. The notch 36 is provided on the outer circumferential surface of the side wall 32 and protrudes outward from the side wall 32. The notch 36 is formed in an annular shape and is provided continuously along the circumferential direction on the outer circumferential surface of the side wall 32. The notch 36 is located below the external thread 33. The notch 36 has the function of restricting the movement of the band portion 26 of the cap 10.

[0028] Now, let's describe the band portion 26 of the cap 10. As shown in Figure 2, a gap is formed between the lower end of the band portion 26 and the portion of the flange 34 that faces the band portion 26 in the vertical direction. This gap is formed for the purpose of preventing tampering. After the cap 10 and spout 30 are assembled, if the cap 10 is removed from the spout 30 while it is still in an unopened state and has never been removed, the band portion 26 will be separated from the rest of the cap 10.

[0029] When the band portion 26 is detached from the rest of the cap 10, the band portion 26 and the rest of the cap become disconnected from each other, and the band portion 26 remains on the spout 30. After opening the stopper 4 once, when the cap 10 is attached to the spout 30, a gap is formed between the base portion 24 and the band portion 26 remaining on the spout 30. This difference in the position of the gap allows for visual confirmation of whether or not the stopper 4 on the packaging container 1 has already been opened.

[0030] As shown in Figures 3 and 4(a), the band portion 26 includes a band body 26a and a plurality of flaps 26b. The band body 26a is the cylindrical portion of the band portion 26. The plurality of flaps 26b are connected to the lower end of the band body 26a and extend toward the top plate 12. The flaps 26b are bent by a jig or the like after molding during the manufacturing process of the cap 10, so that they are positioned inside the band body 26a. Figure 4(a) illustrates the cap 10 before the flaps 26b are bent.

[0031] Multiple flaps 26b are arranged in a circumferential direction. In the installed state (more specifically, the unopened state described above), the tip of each of the multiple flaps 26b faces the lower surface of the notch 36 of the spout 30. When attempting to remove the cap 10 during the opening of the spout 4, each flap 26b contacts the lower surface of the notch 36, thereby restricting the cap 10 from moving away from the spout 30.

[0032] The cap 10 has a break portion 28. The break portion 28 connects the band portion 26 to the peripheral wall 14 such that when the cap 10 is removed from the spout 30, the band portion 26 is separated from the rest of the cap 10. The break portion 28 includes, for example, a plurality of ribs 28a. Each of the plurality of ribs 28a is positioned between adjacent flaps 26b in the circumferential direction. The ribs 28a are provided on the inner circumferential surface of the band body 26a and the inner circumferential surface of the base portion 24 of the peripheral wall 14, and protrude inward from their inner circumferential surfaces.

[0033] A notch 28b is formed at the boundary between the lower end of the base portion 24 and the upper end of the band body 26a, extending into the interior of each rib 28a. The notch 28b is formed in an annular shape, and the peripheral wall 14 and the band portion 26 are separated by the notch 28b. When the portion of each rib 28a at the height of the notch 28b where the notch 28b is not formed is called the "thin-walled portion 28c", the peripheral wall 14 and the band portion 26 are connected via the thin-walled portion 28c. Then, when the thin-walled portion 28c of each rib 28a breaks, the band portion 26 is separated.

[0034] As shown in Figures 3 and 4(b), the spout 30 has a projection 40. The projection 40 is provided on the inner circumferential surface of the side wall 32. The projection 40 is formed to contact the inner circumferential surface of the inner ring 16 when the cap 10 is attached to the spout 30. In the attached state, a portion of the projection 40 contacts the inner circumferential surface of the inner ring 16. The projection 40 is located above the notch 36. The projection 40 includes, for example, a small wall portion 42, a connecting portion 44, and an engaging portion 46.

[0035] The small wall portion 42 has a cylindrical shape and is positioned inward from the side wall 32 with a gap between them. Observing the cross-sectional portion in the longitudinal section, the small wall portion 42 extends along the vertical direction. The connecting portion 44 is the part that connects the small wall portion 42 and the side wall 32 and is formed in an annular shape. The connecting portion 44 connects, for example, the outer peripheral surface of the lower part of the small wall portion 42 to the part of the inner peripheral surface of the side wall 32 that is located in the center in the vertical direction.

[0036] The engaging portion 46 is formed to extend diagonally upward from the upper end of the small wall portion 42 toward the side wall 32, and is annular in shape. A space is formed between the engaging portion 46 and the side wall 32, into which a portion of the inner ring 16, including its lower end, is inserted in the installed state. The outermost portion of the engaging portion 46 (hereinafter referred to as the "contact portion 46a") contacts the inner circumferential surface of the inner ring 16. In the installed state, the contact portion 46a of the engaging portion 46 contacts the inner circumferential surface of the inner ring 16 around the entire circumference of the central axis Ax (for example, line contact).

[0037] Figure 5 shows an enlarged portion of the cross-sectional view in Figure 3. The inner ring 16 may include a first inner portion 16a and a second inner portion 16b. The second inner portion 16b and the first inner portion 16a are arranged in this order from the top plate 12 in the vertical direction. In the installed state, the first inner portion 16a is inserted into the space between the engaging portion 46 of the protruding portion 40 and the side wall 32. The outer diameter (outermost diameter) of the second inner portion 16b is larger than the outer diameter (outermost diameter) of the first inner portion 16a. In the installed state, the first inner portion 16a and the second inner portion 16b each contact the inner circumferential surface of the side wall 32.

[0038] The portion of the side wall 32 above the location where the protrusion 40 is provided includes a first cylindrical portion 32a corresponding to the first inner portion 16a and a second cylindrical portion 32b corresponding to the second inner portion 16b. The second cylindrical portion 32b and the first cylindrical portion 32a are arranged in this order from the top plate 12 in the vertical direction. The inner diameter (minimum inner diameter) of the second cylindrical portion 32b is larger than the inner diameter (minimum inner diameter) of the first cylindrical portion 32a. In the installed state, the outer circumferential surface of the first inner portion 16a contacts (fits tightly) the inner circumferential surface of the first cylindrical portion 32a, and the outer circumferential surface of the second inner portion 16b contacts (fits tightly) the inner circumferential surface of the second cylindrical portion 32b.

[0039] In Figure 5, the position where the first inner portion 16a contacts the first cylindrical portion 32a is indicated by a dashed circle labeled "II," and the position where the second inner portion 16b contacts the second cylindrical portion 32b is indicated by a dashed circle labeled "III." Note that in Figures 3 and 5, the contact points between the inner ring 16 and the side wall 32 are drawn overlapping. In the actual installed state, at least one of the members deforms due to the contact.

[0040] In the installed state, the upper end of the side wall 32, which is inserted between the inner ring 16 and the peripheral wall 14, contacts the lower surface of the top plate 12. The upper end of the side wall 32 corresponds to the tip of the side wall 32. The lower surface of the top plate 12 may include a curved surface 12a that protrudes downward, and the upper end of the side wall 32 may contact this curved surface 12a. In the installed state, the upper end of the side wall 32 contacts the lower surface of the top plate 12 all around the central axis Ax (for example, line contact). In Figure 5, the position where the upper end of the side wall 32 contacts the lower surface of the top plate 12 is indicated by a dashed circle labeled "IV".

[0041] A portion of the inner circumferential surface of the inner ring 16, including the tip, is formed to extend along the vertical direction (central axis Ax). This portion of the inner ring 16, including the tip, is the part that is inserted into the space between the engaging portion 46 of the protruding portion 40 and the side wall 32 when installed. When installed, the contact portion 46a of the engaging portion 46 contacts the inner circumferential surface of the first inner portion 16a. In Figure 5, the position where the contact portion 46a of the engaging portion 46 contacts the inner circumferential surface of the first inner portion 16a is indicated by a dashed circle labeled "I".

[0042] If the cap 10 is made of a harder material than the spout 30, the spout 30 may deform rapidly when the packaging container 1 is dropped or otherwise subjected to such forces. If the engaging portion 46 is not provided, it would be difficult for the cap 10 to follow such rapid deformation. However, the provision of the engaging portion 46 makes it easier for the cap 10 to follow the deformation of the spout 30. This reduces the possibility of liquid leakage occurring from the gap between the cap 10 and the spout 30.

[0043] <Internal pressure changes and sealing performance> Here, with reference to Figures 6(a), 6(b), and 6(c), the relationship between the change in internal pressure of the packaging container 1 and the airtightness of the spout 4 will be explained. The internal pressure of the packaging container 1 can change depending on the environment, such as increasing instantaneously due to the impact when the packaging container 1 is dropped, or decreasing due to cooling after relatively high-temperature contents have been filled in. This change in internal pressure may cause the spout 4 to distort, potentially impairing its airtightness. In the aforementioned spout 4, the engagement portion 46 is provided, making it less likely for the airtightness to deteriorate due to changes in the internal pressure of the packaging container 1.

[0044] When the internal pressure of the packaging container 1 increases, high pressure is also applied to the inner surface of the spout 4, and consequently, high pressure is applied outward to the inner circumferential surface of the inner ring 16. In Figure 6(a), the pressure applied to the inner circumferential surface of the inner ring 16 is illustrated by the white arrows. The high pressure applied outward causes the outer circumferential surface of the inner ring 16 to be pressed more firmly against the inner circumferential surface of the side wall 32, improving the sealing performance. Specifically, the outer circumferential surface of the first inner portion 16a and the inner circumferential surface of the first cylindrical portion 32a become more closely fitted, and the outer circumferential surface of the second inner portion 16b and the inner circumferential surface of the second cylindrical portion 32b become more closely fitted. The increased degree of contact at these two locations maintains the sealing performance.

[0045] In addition to the inner surface of the inner ring 16, high pressure is also applied to the top plate 12 from bottom to top. This pressure causes the central part of the top plate 12 to bulge upward, and as a reaction, an inward stress is generated in the lower part of the inner ring 16. In Figure 6(b), the pressure applied to the top plate 12 is illustrated by the white arrow, and the stress generated in the lower part of the inner ring 16 is illustrated by the black arrow. In this case, the inner surface of the inner ring 16 is pressed against the engaging portion 46 of the protrusion 40, and the sealing is maintained by the point where the contact portion 46a of the engaging portion 46 and the inner surface of the inner ring 16 (first inner portion 16a) are in close contact with each other.

[0046] Furthermore, with respect to the stress generated in the lower part of the inner ring 16, the engaging portion 46 restricts the inner ring 16 from separating from the inner circumferential surface of the side wall 32. Specifically, the first inner portion 16a is restricted from separating from the first cylindrical portion 32a, and the second inner portion 16b is restricted from separating from the second cylindrical portion 32b, thereby maintaining airtightness between the inner ring 16 and the side wall 32. In addition, from the viewpoint of achieving both airtightness between the first inner portion 16a and the first cylindrical portion 32a, and between the second inner portion 16b and the second cylindrical portion 32b, the engaging portion 46 is in contact with the first inner portion 16a.

[0047] When the internal pressure of the packaging container 1 decreases, high pressure is applied inward to the inner ring 16, and high pressure is applied from top to bottom to the top plate 12. In Figure 6(c), the pressures applied to the inner ring 16 and the top plate 12 are illustrated by the white arrows. As a result of the pressure applied to the inner ring 16, stress is generated inward in the inner ring 16, the central part of the top plate 12 bulges downward, and in reaction to this, further inward stress is generated in the second inner part 16b of the inner ring 16.

[0048] Even if inward stress is generated in the inner ring 16 due to a decrease in internal pressure, the inner surface of the inner ring 16 is pressed against the engaging portion 46 of the protrusion 40, and the sealing performance is maintained at the point where the contact portion 46a of the engaging portion 46 and the inner surface of the inner ring 16 are in close contact with each other. In addition, the engaging portion 46 prevents the inner ring 16 from separating from the inner surface of the side wall 32. As a result, the sealing performance is maintained even if the internal pressure of the packaging container 1 decreases.

[0049] <Dimensions> Returning to Figures 4(a) and 4(b), the dimensions that may affect the sealing performance of the inner ring 16, side wall 32, and protrusion 40 will be described. The dimensions described below refer to the dimensions in the non-attached state (when the cap 10 is not attached to the spout 30). The dimensions in the non-attached state may be measured, for example, after the cap 10 and spout 30 have been manufactured but before they are assembled.

[0050] As described above, when the cap 10 is attached to the spout 30 (for example, when it is first assembled), the tip of the inner ring 16 is inserted into the space between the side wall 32 and the engaging portion 46. Here, the outer diameter A, inner diameter B, and abutment amount (AB) are defined as follows. Outer diameter A: The outer diameter of the portion of the protruding part 40 that contacts the inner circumferential surface of the inner ring 16 (contact portion 46a). Inner diameter B: Inner diameter of the tip of inner ring 16 Auction amount (AB): The value obtained by subtracting the inner diameter B from the outer diameter A.

[0051] If the outer diameter A is larger than the inner diameter B, the amount of interference (AB) will be a positive value, meaning that there is interference between the engaging portion 46 and the inner ring 16 when the ring is not installed. Even if there is some interference, the space between the side wall 32 and the engaging portion 46 will be slightly widened when the inner ring 16 is inserted, and the tip of the inner ring 16 (first inner portion 16a) will be inserted into that space.

[0052] If the outer diameter A is smaller than the inner diameter B, the abutment amount (AB) will be a negative value, meaning that there is a gap between the engaging portion 46 and the inner ring 16 when it is not installed. Even if there is a small gap, as a portion of the side wall 32, including the tip, is inserted into the space between the inner ring 16 and the peripheral wall 14, the inner ring 16 moves inward, and the inner ring 16 (first inner portion 16a) and the engaging portion 46 come into contact with each other.

[0053] From the viewpoint of preventing a decrease in sealing performance due to the inner ring 16 separating from the inner circumferential surface of the side wall 32, the abutment amount (AB) is -0.15 mm or more. From the viewpoint of more reliably preventing a decrease in sealing performance due to the inner ring 16 separating from the inner circumferential surface of the side wall 32, the abutment amount (AB) may be -0.14 mm or more, -0.12 mm or more, -0.11 mm or more, or -0.10 mm or more.

[0054] If the axle length (AB) is large, excessive force (torque) may be required when assembling the cap 10 to the spout 30, and the tip of the inner ring 16 may not contact the underside of the top plate 12. In this case, the airtightness may be reduced due to the gap between the tip of the inner ring 16 and the underside of the top plate 12. From the viewpoint of preventing such a reduction in airtightness, the axle length (AB) is 0.02 mm or less. From the viewpoint of further reducing the possibility of reduced airtightness due to the gap between the tip of the inner ring 16 and the underside of the top plate 12, the axle length (AB) may be 0.015 mm or less, 0.01 mm or less, 0.005 mm or less, or 0.001 mm or less. The axle length (AB) may also be 0 mm.

[0055] The upper and lower limits of the bidding amount (AB) may be any combination of the values ​​mentioned above. For example, the bidding amount (AB) is -0.15mm to 0.02mm, -0.15mm to 0.01mm, or -0.10mm to 0.001mm. The outer diameter A may be 12.0mm to 18.0mm, 13.0mm to 17.0mm, or 14.0mm to 16.0mm. The outer diameter A and inner diameter B may be measured using an image measuring instrument (e.g., Mitutoyo Corporation's "QS250Z") or a caliper (e.g., Mitutoyo Corporation's "Digimatic Caliper" (model number: CD-15AX)). For example, the outer diameter A can be determined by selecting 10 points at approximately equal intervals on the outer edge of the contact area 46a measured by the image measuring instrument, calculating a pseudo-circle, and then identifying the outer diameter A from that pseudo-circle. In one example, the inner diameter B can be determined by taking five measurements at two mutually orthogonal points using the caliper described above, and then calculating the arithmetic mean of these measurements.

[0056] The outer diameter of the peripheral wall 14 that defines the size of the cap 10 may be 22.0 mm to 28.0 mm, 23.0 mm to 27.0 mm, or 24.0 mm to 26.0 mm. The shortest distance between the top surface of the top plate 12 (the flat surface of the top surface) and the lower end of the band portion 26 may be 12.0 mm to 18.0 mm, 13.0 mm to 17.0 mm, or 14.0 mm to 16.0 mm. The outer diameter of the side wall 32 (the diameter of the flat surface of the outer circumferential surface of the side wall 32 that does not have external threads 33 and notches 36) may be 18.0 mm to 24.0 mm, 19.0 mm to 23.0 mm, or 20.0 mm to 22.0 mm. The shortest distance between the bottom surface of the top plate 12 (the flat surface located inside the inner ring 16 on the bottom surface) and the lower end of the inner ring 16 may be 4.0 mm to 6.0 mm, 4.2 mm to 5.8 mm, or 4.4 mm to 5.6 mm.

[0057] The outer diameter of the first inner portion 16a of the inner ring 16 (the outer diameter at the outermost part of the first inner portion 16a) may be 14.0 mm to 20.0 mm, 15.0 mm to 19.0 mm, or 16.0 mm to 18.0 mm. The difference obtained by subtracting the outer diameter of the first inner portion 16a from the outer diameter of the second inner portion 16b (the outer diameter at the outermost part of the second inner portion 16b) may be 0.3 mm to 0.9 mm, 0.35 mm to 0.85 mm, or 0.4 mm to 0.8 mm.

[0058] The outer diameter of the first inner portion 16a is larger than the inner diameter of the first cylindrical portion 32a in the side wall 32 of the spout 30. The difference obtained by subtracting the inner diameter of the first cylindrical portion 32a from the outer diameter of the first inner portion 16a may be 0.1 mm to 0.5 mm, 0.15 mm to 0.45 mm, or 0.2 mm to 0.4 mm. The outer diameter of the second inner portion 16b is larger than the inner diameter of the second cylindrical portion 32b in the side wall 32. The difference obtained by subtracting the inner diameter of the second cylindrical portion 32b from the outer diameter of the second inner portion 16b may be 0.1 mm to 0.5 mm, 0.15 mm to 0.45 mm, or 0.2 mm to 0.4 mm.

[0059] The spout 30 is manufactured, for example, by resin molding using a mold. When the shortest distance (hereinafter referred to as "distance r") between the outer diameter A of the engaging portion 46 and the inner diameter of the second cylindrical portion 32b becomes smaller, the mold thickness in the portion corresponding to the space between the engaging portion 46 and the second cylindrical portion 32b decreases, and the durability of the mold decreases. From the viewpoint of mold durability, the distance r may be 0.3 mm or more, 0.4 mm or more, or 0.5 mm or more.

[0060] On the other hand, as the distance r increases, the thickness (width) of the inner ring 16 of the cap 10 also needs to be increased, and increasing the thickness of the inner ring 16 can lead to dimensional changes due to molding defects. As a result, the sealing performance may decrease. Furthermore, as the amount of resin increases, the weight of the cap 10 increases, and the cost also rises. From the standpoint of preventing these problems, the distance r may be 0.8 mm or less, 0.75 mm or less, or 0.7 mm.

[0061] [Method for manufacturing a mouthpiece] Next, an example of a method for manufacturing the spout 4 will be described. The method for manufacturing the spout 4 includes at least the steps of preparing the spout 30, preparing the cap 10, and assembling the cap 10 and the spout 30. In the step of preparing the spout 30, for example, the spout 30 is manufactured by resin molding using a mold.

[0062] In the process of preparing the cap 10, first, a cap member corresponding to the cap 10 is prepared. In preparing the cap member, for example, a cap member in which the portion corresponding to the peripheral wall 14 and the portion corresponding to the band portion 26 are integrated is manufactured by resin molding. The cap member has the same shape as the cap 10, except that the notches 28b and the thin-walled portion 28c (break portion 28) are not formed. After the cap member is manufactured by resin molding, a plurality of flaps 26b may be folded into the internal space of the cap member.

[0063] After preparing the cap member, a notch 28b is formed in the cap member to create a fractured portion 28. For example, a score cutter is used to make cuts around the entire circumference of the peripheral wall of the cap member to create the notch 28b. The formation of the fractured portion 28 separates the peripheral wall 14 and the band portion 26, and these members are connected via the rib 28a (thin-walled portion 28c), resulting in the cap 10. In the process of preparing the cap 10, instead of forming the thin-walled portion 28c by making cuts after resin molding, resin molding may be performed in such a way that the thin-walled portion 28c is formed.

[0064] In the process of assembling the spout 30 and the cap 10, first, the upper end of the side wall 32 of the spout 30 is inserted into the circumferential wall 14 of the cap 10. Then, when the cap 10 is rotated in one direction in the circumferential direction relative to the spout 30 (rotated in the tightening direction), the internal thread 15 of the circumferential wall 14 and the external thread 33 of the side wall 32 engage, and the cap 10 moves toward the spout 30. The tightening of the cap 10 may be performed by machine, or a constant torque may be applied to each individual unit. As the rotation of the cap 10 continues, multiple flaps 26b move over the notches 36, and the cap 10 is assembled to the spout 30.

[0065] In the process of assembling the cap 10 by rotating it onto the spout 30, a portion of the side wall 32, including its upper end, is inserted between the inner ring 16 and the peripheral wall 14, while the first inner portion 16a of the inner ring 16 is inserted between the engaging portion 46 of the protruding portion 40 and the side wall 32. At this time, a portion of the side wall 32, including its upper end, may be inserted between the inner ring 16 and the peripheral wall 14 while deforming to spread outward. Furthermore, regarding the contact between the inner ring 16 and the side wall 32, the second inner portion 16b may contact the second cylindrical portion 32b first, and then the first inner portion 16a may contact the first cylindrical portion 32a. By having the contacts occur sequentially in this way, the torque required to tighten the cap 10 can be minimized. After that, the process of attaching the spout 4 to the container body 2 is carried out, and the packaging container 1 is manufactured.

[0066] [Differentiation] This disclosure is not limited in any way to the examples described above. The shape of the packaging container 1 (container body 2) may differ from the shape illustrated in Figure 1 and may have a cylindrical shape. The position where the spout 4 is attached to the container body 2 is not limited to the position shown in Figure 1 and may be any position.

[0067] In the example described above, when the cap 10 is first opened, the band portion 26 is separated (cut) from the rest of the cap 10. However, the band portion 26 may be formed such that a part of it remains on the cap 10, even though it is separated from it. The band portion 26 may not be formed at all. In this case, the internal thread 15 may be provided on the inner circumferential surface near the lower end of the peripheral wall 14, and the external thread 33 may be provided on the outer circumferential surface near the lower end of the side wall 32.

[0068] [Verification of airtightness] Next, we will explain the results of verifying the sealing performance under conditions where changes in internal pressure occur by gradually changing the axle amount (AB) described above. Bolts 4 for Examples 1-4 and Comparative Examples 1-4 were manufactured so that the axle amounts (AB) differed for each. The bolts 4 for Examples 1-4 and Comparative Examples 1-4 were formed in the same way as the bolts 4 shown in Figure 2, but for other reasons during verification, some of the bolts 4 were made to have a band portion 26, while other bolts 4 were made to not have a band portion 26. In the bolts 4 for Examples 1-4 and Comparative Examples 1-4, the axle amounts (AB) were set to the values ​​shown in Table 1 below, and the main dimensions other than the outer diameter A and inner diameter B were set to the range described in the dimensional relationship above.

[0069] [Table 1]

[0070] Block polypropylene (product name: PM970A, manufactured by Sun Allomer Co., Ltd.) was used to form the cap 10, and low-density polyethylene (product name: M2170, manufactured by Asahi Kasei Corporation) was used to form the spout 30. Using the screw cap torque meter "DTXA-2N-Z" manufactured by Imada Co., Ltd., the cap 10 was closed against the spout 30 with a torque of 90 N·cm. During closing, a fixing jig was used instead of manual work to prevent the load from fluctuating by gripping the cap 10. For those with a band portion 26, the cap was closed after forming a cut 28b partway through the rib 28a.

[0071] A container body 2 (85mm square paper carton, gable top) with a capacity of 1.8L was prepared. The layer structure of the container body 2 consisted of layers of PE (polyethylene), paper, PE, transparent barrier film, and PE, in that order from the outside. After fixing the spout 4 to the container body 2, 1.8L of hot water was poured into the container body 2 to obtain a packaging container 1 containing the contents. The hot water was prepared so that the temperature inside the container body 2 was 85°C. After filling with hot water, the packaging container 1 was left to stand at room temperature conditions of 25°C until the contents returned to room temperature. In each of Examples 1 to 4 and Comparative Examples 1 to 4, nine packaging containers 1 were prepared under the same conditions, with the contents at room temperature.

[0072] <Evaluation by drop test> Using nine packaging containers prepared under the same conditions, the following three types of drop tests were conducted. • Test a (inverted drop): As shown in Figure 7(a), the inverted packaging container 1 is dropped once from a height of 70 cm. • Test b (sideways drop): As shown in Figure 7(b), the packaging container 1 is dropped once from a height of 1 m in a sideways position with the spout 4 facing downwards. • Test c (drop as stipulated by the Food Sanitation Act): As shown in Figure 7(c), the packaging container 1, lying on its side with the spout 4 facing downwards, is dropped twice from a height of 30 cm.

[0073] In the drop test according to Example 1, test a was performed using three packaging containers 1 (which had been cooled to room temperature after being filled with hot water) according to Example 1. Test b was performed using three other packaging containers 1 according to Example 1, and test c was performed using three more packaging containers 1 according to Example 1. Similarly, in Examples 2 to 4 and Comparative Examples 1 to 4, tests a, b, and c were performed using nine packaging containers 1.

[0074] To evaluate the airtightness after the drop test, we checked for water leakage at the positions indicated by "P1," "P2," "P3," and "P4" in Figure 5. Between the spout 30 and the cap 10, a path (gap) can be formed through which water flows from the inside to the outside of the container body 2. Along this path, positions P1, P2, P3, and P4 are arranged in this order when observed from the inside to the outside of the container body 2.

[0075] To check for water leaks, after the drop test described above, X-ray CT imaging was performed using the "NAOMI-CT" X-ray CT scanner manufactured by RF Co., Ltd. to obtain a longitudinal cross-sectional image of the spout 4. During the X-ray CT imaging, the tube voltage was set to 50kV and the current to 2mA. The CT images acquired around the entire 360° were visually inspected to confirm the location of the water leak.

[0076] The following criteria were used to evaluate the airtightness, and the average value (arithmetic mean) of the results from three types of drop tests was calculated as the evaluation index. • Sealing up to the contact point between the first inner section 16a and the first cylindrical section 32a (no water leakage at positions P2, P3, and P4): 3 points • Sealing up to the contact point between the second inner section 16b and the second cylindrical section 32b (no water leakage at positions P3 and P4): 2 points • Sealed up to the point where the upper end of the side wall 32 contacts the lower surface of the top plate 12 (no water leakage at position P4): 1 point • Water leak at location P4: 0 points

[0077] In Figure 5, position P4 refers to the vicinity of the upper end of the side wall 32, but on the above path, it means the section downstream from the point of contact between the upper end of the side wall 32 and the lower surface of the top plate 12. A borderline BL representing whether or not airtightness is maintained was set to 1.5 points. That is, if the index value is 1.5 points or higher, it is evaluated that airtightness is maintained, and if the index value is less than 1.5 points, it is evaluated that airtightness is not maintained.

[0078] Figure 8 shows a graph plotting the index values ​​representing the evaluation results for Examples 1-4 and Comparative Examples 1-4. As shown in Figure 8, it can be seen that the index values ​​exceed the borderline BL when the auction volume (AB) is 0.00 mm, -0.03 mm, -0.07 mm, and -0.10 mm (Examples 1-4). On the other hand, it can be seen that the index values ​​fall below the borderline BL when the auction volume (AB) is 0.15 mm, 0.09 mm, 0.03 mm, and -0.20 mm (Comparative Examples 1-4).

[0079] Figure 9(a) shows an example of a CT image obtained when the auction amount (AB) is -0.20 mm. Observing the position indicated by IVa, contact between the lower surface of the top plate 12 and the upper end of the side wall 32 can be confirmed. However, in Comparative Example 4, the gap between the engaging portion 46 and the inner ring 16 in the non-mounted state was large, and the force acting from the engaging portion 46 on the inner ring 16 during the drop test was weak, which is thought to have reduced the tightness between the inner ring 16 and the side wall 32.

[0080] Figure 9(b) shows an example of a CT image obtained when the auction amount (AB) is -0.10 mm to 0.00 mm. Observing the position indicated by IVb, contact between the lower surface of the top plate 12 and the upper end of the side wall 32 can be confirmed. In Examples 1 to 4, the gap between the engaging portion 46 and the inner ring 16 in the non-mounted state was relatively small, and it is considered that an appropriate force was applied from the engaging portion 46 to the inner ring 16 during the drop test, thus maintaining the sealing performance.

[0081] Figure 9(c) shows an example of a CT image obtained when the abutment amount (AB) is 0.03 to 0.15 mm. Observing the position indicated by IVc, it can be confirmed that a gap exists between the lower surface of the top plate 12 and the upper end of the side wall 32. In comparative examples 1 to 3, the abutment amount between the engaging portion 46 and the inner ring 16 was large in the non-installed state, which increased resistance when closing the cap 10 (increasing the torque required to achieve the desired state), and it is thought that the upper end of the side wall 32 could not contact the lower surface of the top plate 12, resulting in a decrease in sealing performance.

[0082] From the above results, it can be seen that, compared to Comparative Examples 1 to 4, Examples 1 to 4 were able to maintain the airtightness of the packaging container 1 even under conditions where the internal pressure changed.

[0083] [Summary of this disclosure] The spout 4 described above comprises a spout 30 and a cap 10 that can be attached to the spout 30. The spout 30 has a cylindrical side wall 32, a flange 34 provided on one end of the side wall 32, and a projection 40 provided on the inner circumferential surface of the side wall 32. The cap 10 has a top plate 12, a circumferential wall 14 connected to the outer edge of the top plate 12, and a cylindrical inner ring 16 connected to the inside of the outer edge of the top plate 12. The projection 40 of the spout 30 is formed to contact the inner circumferential surface of the inner ring 16 when the cap 10 is attached to the spout 30. When the cap 10 is not attached to the spout 30 (non-attached state), the outer diameter A and inner diameter B are defined as follows: Outer diameter A: the outer diameter of the portion of the protruding part 40 that contacts the inner circumferential surface of the inner ring 16 (contact portion 46a), and Inner diameter B: the inner diameter of the tip of the inner ring 16. In this case, the axle amount (AB) obtained by subtracting the inner diameter B from the outer diameter A is -0.15 mm to 0.02 mm.

[0084] As described above, the internal pressure of the container body 2 to which the spout 4 is attached may change due to the dropping of the container body 2 or the filling of high-temperature contents. When such a change in internal pressure occurs, the degree of airtightness between the cap 10 and the spout 30 may decrease. As a result of our verification, we found that even if the protrusion 40 (engaging portion 46) is provided, the following problems may occur when the internal pressure of the container body 2 changes. If the axle (AB) is less than -0.15 mm, the degree of airtightness between the inner ring 16 and the side wall 32 decreases, which may reduce the sealing performance. Also, if the axle (AB) is greater than 0.02 mm, the torque required to achieve the desired state when assembling the cap 10 and the spout 30 increases, which may result in a gap between the side wall 32 and the top plate 12, reducing the sealing performance. With the above-mentioned spout 4, the auction amount (AB) is -0.15 mm or more and 0.02 mm or less, so the airtightness is maintained even when the internal pressure of the container body 2 changes. Therefore, the above-mentioned spout 4 is useful for improving airtightness.

[0085] In the spout 4 described above, a portion of the inner circumferential surface of the inner ring 16, including the tip portion, may be formed to extend along the central axis Ax of the spout 4. In this case, when assembling the cap 10 and the spout 30, the resistance associated with the contact between the inner circumferential surface of the inner ring 16 and the portion of the protrusion 40 (contact portion 46a) is small. Therefore, it is possible to suppress the increase in torque required to achieve the desired state due to the provision of the protrusion 40. This is therefore even more useful for improving sealing performance.

[0086] In the spout 4 described above, the inner ring 16 may include a first inner portion 16a and a second inner portion 16b having a larger outer diameter than the first inner portion 16a. The first inner portion 16a and the second inner portion 16b may be arranged in this order from the top plate 12. The side wall 32 of the spout 30 may include a first cylindrical portion corresponding to the first inner portion 16a and a second cylindrical portion corresponding to the second inner portion 16b. When the cap 10 is attached to the spout 30, the outer circumferential surface of the first inner portion 16a may contact the inner circumferential surface of the first cylindrical portion 32a, and the outer circumferential surface of the second inner portion 16b may contact the inner circumferential surface of the second cylindrical portion 32b. In this case, at least two contact points are formed between the inner circumferential surface of the side wall 32 and the outer circumferential surface of the inner ring 16. Therefore, this is even more useful for improving sealing performance.

[0087] In the spout 4 described above, when the cap 10 is attached to the spout 30, the portion of the protrusion 40 (contact portion 46a) may contact the inner surface of the inner ring 16 around the entire circumference of the central axis Ax of the spout 4. In this case, leakage of the contents is prevented around the entire circumference, which is further useful for improving the sealing performance.

[0088] In the spout 4 described above, when the cap 10 is attached to the spout 30, the tip of the side wall 32 may come into contact with the underside of the top plate 12 around the entire circumference of the central axis Ax of the spout 4. In this case, leakage of the contents is prevented around the entire circumference, which is further useful for improving airtightness.

[0089] The packaging container 1 described above comprises a spout 4 and a container body 2 to which the spout 4 is attached. Because this packaging container 1 is equipped with the aforementioned spout 4, it is useful for improving airtightness. [Explanation of symbols]

[0090] 1...Packaging container, 2...Container body, 4...Spout, 10...Cap, 12...Top plate, 14...Surface wall, 16...Inner ring, 16a...First inner part, 16b...Second inner part, 30...Spout, 32...Side wall, 34...Flange, 40...Protruding part, 46...Engaging part, 46a...Contact part.

Claims

1. A spout comprising a spout and a cap that can be attached to the spout, The aforementioned spout is Cylindrical side wall, A flange provided on one end of the aforementioned side wall, It has a protrusion provided on the inner circumferential surface of the side wall, The aforementioned cap is The tabletop and A peripheral wall connected to the outer edge of the top plate, It has a cylindrical inner ring connected to the inside of the outer edge of the top plate, The protruding portion of the spout is formed to contact the inner circumferential surface of the inner ring when the cap is attached to the spout. The outer diameter A and inner diameter B when the cap is not attached to the spout are as follows: Outer diameter A: The outer diameter of the portion of the protrusion that contacts the inner circumferential surface of the inner ring. Inner diameter B: Inner diameter of the tip of the inner ring A spout, defined as such, wherein the auction amount (A-B) obtained by subtracting the inner diameter B from the outer diameter A is between -0.15 mm and 0.02 mm.

2. A portion of the inner circumferential surface of the inner ring, including the tip portion, is formed to extend along the central axis of the plug. The spout according to claim 1.

3. The inner ring includes a first inner portion and a second inner portion having a larger outer diameter than the first inner portion. The second inner section and the first inner section are arranged in this order from the top plate. The side wall of the spout includes a first cylindrical portion corresponding to the first inner portion and a second cylindrical portion corresponding to the second inner portion. When the cap is attached to the spout, the outer circumferential surface of the first inner portion contacts the inner circumferential surface of the first cylindrical portion, and the outer circumferential surface of the second inner portion contacts the inner circumferential surface of the second cylindrical portion. The spout according to claim 1.

4. When the cap is attached to the spout, the portion of the protrusion contacts the inner surface of the inner ring around the entire circumference of the central axis of the spout. A spout according to any one of claims 1 to 3.

5. When the cap is attached to the spout, the tip of the side wall contacts the underside of the top plate around the entire circumference of the central axis of the spout. A spout according to any one of claims 1 to 3.

6. A stopper according to any one of claims 1 to 3, A packaging container comprising a container body to which the aforementioned spout is attached.

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