Synthetic Resin Cap

Abstract

To provide a synthetic resin cap capable of suppressing the intrusion of shower water into the cap, regardless of the fitting state between an upper lid and a cap body. [Solution] The synthetic resin cap of the present invention is a synthetic resin cap including an upper lid and a cap body, and a first water guide groove extending in the axial direction is formed on the lower end surface of the skirt wall that contacts the cap body, and the radial groove width of the first water guide groove is narrower than the gap GP1 of the narrow portion formed by the outer wall of the cap body and the lower end of the inner surface of the skirt wall.

Description

[Technical Field]

[0001] The present invention relates to a synthetic resin cap comprising a cap body that is attached to the mouth of a container, and a top lid that is attached to the cap body via a hinged connection portion so as to be openable and closable. [Background technology]

[0002] Synthetic resin caps serving as hinge caps consisting of a cap body and a top lid are used for containers filled with contents such as beverages and seasonings. In particular, when the contents are seasonings such as soy sauce or mirin, heated contents are filled into the container during the manufacturing process. After the heated contents are filled into the container and the cap is attached with the lid closed, the container and cap are cooled by spraying a liquid (also called shower water) on the outside of the container and cap. During this manufacturing process, the air inside the cap expands due to the high-temperature contents, and the internal pressure of the cap is reduced (negative pressure) due to the effect of the shower water. This pressure change can cause the shower water to seep into the cap through the gap between the top lid and the cap body (water ingress).

[0003] To address this shower water ingress phenomenon, Patent Document 1 discloses a method for forming a flexible ring at the lower end of the outer lid, which is located closer to the center than the annular groove, by providing an annular groove that opens to the end surface when the lid is closed. Patent Document 2 also discloses a method for forming a recessed groove that forms a space cut into the lid at a height equal to or greater than the height of the inner surface of the mating part, thereby forming a thin, deformable wall between the recessed groove in the side peripheral wall and the inner surface of the mating part. Patent Document 3 also discloses a method for positioning the pressure contact between the top lid and the sealing tube of the cap body at a position that is less susceptible to deformation caused by plugging the cap body and that effectively prevents cooling water from being sucked in. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-270541 [Patent Document 2] Japanese Patent Application Publication No. 2018-090273 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-040259 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technologies including those described in the above patent documents still cannot be said to meet market needs, and at least the following problems exist. That is, until now, it has been assumed that the water ingress caused by shower water is caused by pressure changes inside the cap, as shown in the above-mentioned patent documents. After extensive research, the inventors have found that such pressure changes are indeed the main cause of the water ingress, and have focused on the fact that the water ingress is also caused by capillary action, whereby shower water is sucked up by a minute gap that occurs at the fitting portion between the top lid and the cap body.

[0006] It would be ideal to completely eliminate gaps at the fitting portion to prevent this capillary phenomenon from occurring. However, because the fitting state between the top lid and the cap body depends on the stoppering state and manufacturing errors, it is difficult to eliminate minute gaps at the fitting portion between the top lid and the cap body, even if the fitting state is strengthened as in the above-mentioned patent documents. In other words, the prior art, including the patent documents, does not recognize or mention the problem of water seepage due to the above-mentioned capillary phenomenon, and it can be said that there is still much room for improvement in preventing the above-mentioned water seepage phenomenon.

[0007] Therefore, one object of the present invention is to provide a synthetic resin cap that can prevent shower water from entering the inside of the cap, regardless of the state of fit between the top lid and the cap body, for example. [Means for solving the problem]

[0008] In order to solve the above problems, one form of the synthetic resin cap of the present invention is a synthetic resin cap including: (1) an upper lid having a top plate and a skirt wall descending from the periphery of the top plate; a top wall; a pouring tube extending upward from the top wall; an outer wall descending downward from the outer peripheral edge of the top wall; and a cap body having a body undercut that fits with an upper lid undercut formed on the inner surface of the skirt wall outside the pouring tube, and which is attached to the mouth of a container; wherein a first water guide groove extending axially is formed on the lower end surface of the skirt wall that contacts the cap body, and the radial groove width of the first water guide groove is narrower than the spacing GP1 of the narrow portion formed by the outer wall of the cap body and the lower end of the inner surface of the skirt wall.

[0009] In the synthetic resin cap described in (1) above, (2) it is preferable that the upper end of the first water guide groove in the axial direction is positioned lower in the axial direction than the upper cover undercut when the upper cover is in a closed state in which the upper cover blocks the dispensing tube.

[0010] Furthermore, in the synthetic resin cap described in (2) above, (3) in the closed state, it is preferable that the gap GP2 from the lower end of the inner surface of the skirt wall to the outer peripheral surface of the bottom of the circumferential convex portion where the main body undercut is provided is wider in the radial direction than the spacing GP1 of the narrow portion.

[0011] Furthermore, in the synthetic resin cap described in (3) above, (4) it is preferable that at least one of the skirt wall and the circumferential convex portion has a second water guide groove above the mating portion between the upper cover undercut and the main body undercut in the axial direction.

[0012] Furthermore, in the synthetic resin cap described in (4) above, (5) it is preferable that the second water guide grooves are provided intermittently along the circumferential direction on the receiving surface of the skirt wall that contacts the top surface of the circumferential convex portion.

[0013] In the synthetic resin cap described in any one of (1) to (5) above, (6) it is preferable that the first water guide groove is formed in a ring shape on the lower end surface of the skirt wall.

[0014] Furthermore, in the synthetic resin cap described in any of (1) to (5) above, (7) it is preferable that an inner ring that engages with the dispensing tube is formed on the top plate, and that the cap body and the upper lid are connected via a hinge joint. [Effects of the Invention]

[0015] According to the synthetic resin cap of the present invention, when shower water penetrates into the interior of the cap, the capillary action of the first water guide groove causes the shower water to be drawn toward the first water guide groove rather than through the narrow section formed by the outer wall of the cap body and the lower end of the inner surface of the skirt wall, thereby preventing the shower water from penetrating deep into the interior of the cap. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a partial top view of the synthetic resin cap in an open state according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the synthetic resin cap in a closed state according to the embodiment. [Figure 3] FIG. 3 is an enlarged view of the portion α in FIG. 2. [Figure 4] FIG. 4 is an enlarged view of the β portion in FIG. [Figure 5] 10 is a schematic diagram illustrating the state (first half) of attracting shower water that has entered the synthetic resin cap of the embodiment. FIG. [Figure 6] 10 is a schematic diagram illustrating the attraction state (middle stage) of shower water that has entered the synthetic resin cap of the embodiment. FIG. [Figure 7] 10 is a schematic diagram illustrating the state (later stage) of attracting shower water that has entered the synthetic resin cap of the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment for carrying out the present invention will be described. In this embodiment, the axial direction of the synthetic resin cap attached to the container in an upright state is defined as the Z direction, and the directions perpendicular to the Z direction are defined as the X and Y directions. It goes without saying that the definitions of the X, Y, and Z directions are for convenience only and do not restrict the scope of the present invention.

[0018] In this embodiment, "downward" is defined as downward (negative Z direction) when the container is erected along the Z direction. In this embodiment, "upward" is defined as upward (Z direction) when the container is erected along the Z direction. In addition, the structure of the synthetic resin cap described below may be supplemented as appropriate with the structure of a known hinge cap, including the structures described in the above-mentioned patent documents.

[0019] A synthetic resin cap 100 according to an embodiment will be described with reference to Figures 1 to 4 as appropriate. As can be seen from these figures, the synthetic resin cap 100 is attachable to a known container opening and is configured to include a top lid 10, a cap body 20, and a hinge coupling part 40 that connects the top lid 10 and the cap body 20. The top lid 10 can transition between a closed state and an open state, which will be described later, via the hinge coupling part 40. Note that known hinges, including those described in the patent documents mentioned above, may be used as the specific structure of the hinge coupling part 40.

[0020] Examples of containers equipped with a container mouth 200 include various known bottles capable of storing liquid contents. Such containers are formed with a known container mouth 200 for pouring out the contents, as exemplified in the above-mentioned patent documents. The synthetic resin cap 100 of this embodiment can be plugged or screwed onto the container mouth 200. Furthermore, suitable contents for the container of this embodiment are not particularly limited, but examples include seasonings such as soy sauce and mirin produced through the above-mentioned production process, and beverages containing fruit juice.

[0021] <Top lid 10> 1 and 2, the top cover 10 includes a top panel 11 and a skirt wall 12 that extends downward from the periphery of the top panel 11. The top cover 10 of this embodiment also includes an inner ring 13, a top cover undercut 14, a flange 15, and a protrusion 16.

[0022] The inner ring 13 is configured to descend downward from the top plate 11. The inner ring 13 may be cylindrical and extend from the top plate 11 so that its tip flares outward. This inner ring 13 has the function of engaging with a dispensing tube 22 in the cap body 20 (described later) when the lid is closed, thereby sealing the dispensing tube 22.

[0023] The top cover undercut 14 is formed on the inner peripheral surface of the skirt wall 12. The top cover undercut 14 can be fitted into a main body undercut 24uc, which will be described later, when the top cover is closed. The state in which the top cover undercut 14 and the main body undercut 24uc are fitted together is also referred to as the "closed cover state."

[0024] The flange 15 is a portion that protrudes radially outward from the outer peripheral surface of the skirt wall 12. The flange 15 is provided on the skirt wall 12 on the circumferential side opposite the hinge connection portion 40. When opening the lid, the user can easily detach the top lid 10 from the cap body 20 by hooking their fingers on the flange 15.

[0025] The protrusion 16 is provided on the top panel 11 between the inner ring 13 and the skirt wall 12, and has the function of preventing the contents from immediately dripping out by keeping them on the inner surface of the top lid 10, for example, when used repeatedly.

[0026] <Cap body 20> As can be seen from Figures 2 to 4, the cap body 20 is composed of a top wall 21, a dispensing tube 22, an outer wall 23, a circumferential convex portion 24, a second inner ring 25, a pull ring 26, and a score 27.

[0027] Top wall 21 has the function of covering the opening of the container mouth when cap body 20 is attached to the above-mentioned container. Furthermore, top wall 21 of this embodiment may be provided with a known score 27 on the inside of dispensing tube 22. Top wall 21 is also provided with a known pull ring 26, and when a user breaks score 27 via pull ring 26, an opening through which the contents can be poured appears in top wall 21. Furthermore, as shown in FIG. 2 etc., top wall 21 is provided with a second inner ring 25 that can be in close contact with the inner circumferential surface of the container mouth on the bottom side facing the container mouth.

[0028] The dispensing tube 22 is configured to extend upward from the top wall 21, and the tip of the dispensing tube 22 may be horn-shaped so that the diameter expands radially outward. More specifically, as shown in the figure, the top of the dispensing tube 22 may have a top surface that continues from the inner circumferential surface of the dispensing tube 22, and a curled portion where the tip of this top surface curves outward and downward.

[0029] As shown in FIG. 2 and other figures, the outer wall 23 is configured to descend downward from the outer peripheral edge of the top wall 21. The outer wall 23 may have a double-wall structure to improve sorting and recovery. Specifically, as can be seen from FIG. 2 and other figures, the outer wall 23 of this embodiment includes a first outer wall 23A that can be inscribed with the outer peripheral surface of the container mouth, and a second outer wall 23B that is connected to the lower end of the first outer wall 23A and is disposed with a predetermined gap GP3 between it and the first outer wall 23A. Note that the outer wall 23 does not necessarily have to have a double-wall structure as in this embodiment, in which case the first outer wall 23A and the second outer wall 23B have an integral structure. Furthermore, the upper surface of the outer wall 23 is the surface that comes into contact with the lower end surface 12b of the skirt wall 12 of the top cover 10 when the cover is closed, etc. In this embodiment, the outer wall 23 includes the first outer wall 23A and the second outer wall 23B, and therefore the upper surface of the second outer wall 23B is the surface that comes into contact with the lower end surface 12b of the skirt wall 12 when the cover is closed, etc.

[0030] 2 and other figures, the circumferential protrusion 24 is provided so as to extend upward from the outer peripheral edge of the top wall 21. This circumferential protrusion 24 is provided with a main body undercut 24uc that can fit into the top lid undercut 14 formed on the inner peripheral surface of the skirt wall 12 outside the pouring tube 22. When the top lid 10 is closed, the top lid undercut 14 and the main body undercut 24uc fit together, thereby bringing the top lid 10 and the cap main body 20 into a closed state.

[0031] As shown in Figures 2 to 4, in the closed state, (α) the lower end surface 12b of the skirt wall 12 and the upper surface of the outer wall 23 of the cap body 20 come into contact at a first abutment area FCA, and (β) above this first abutment area FCA, an engagement portion FP is formed by the upper lid undercut 14 and the body undercut 24uc, and further, (γ) above this engagement portion FP, the lower surface of the inward protrusion 17 of the skirt wall 12 and the top surface 24t of the circumferential convex portion 24 come into contact at a second abutment area SCA.

[0032] <Water channel 30> As described above, in the shower process after filling the container with hot contents, water may enter the container due to changes in the internal pressure of the cap or capillary action. In response to this problem, conventional approaches including those described in the above patent documents have mainly been to adjust the degree of engagement between the top lid and the cap body while balancing the degree of engagement and ease of opening.

[0033] It is true that tightening the fit between the top lid and the cap body can prevent water from entering through the gap between them to some extent. However, even if the fit is adjusted while maintaining easy-open properties, the fit between the top lid and the cap body is not uniform, depending on the plugging condition and manufacturing errors, and it is difficult to completely eliminate the gap at the fit to prevent capillary action from occurring.

[0034] Therefore, in the synthetic resin cap 100 of this embodiment, even if liquid (shower water) seeps into the inside of the cap due to the above-mentioned pressure change or capillary phenomenon, a mechanism is introduced to guide the liquid that has seeped in to another location so that it does not flow inward from the fitting portion FP through the fitting portion. That is, the synthetic resin cap 100 of this embodiment is provided with a water guide groove 30 that can guide the liquid (shower water) that has seeped into the inside of the cap to another location without flowing inward from the fitting portion FP.

[0035] More specifically, the water guide groove 30 of this embodiment is configured to include a first water guide groove 31 and a second water guide groove 32. The skirt wall 12 may be provided with at least one of the first water guide groove 31 and the second water guide groove 32. As an example, the synthetic resin cap 100 of this embodiment may omit the second water guide groove 32.

[0036] The first water guiding groove 31 is formed to extend in the axial direction (upward in the Z direction) on the lower end surface 12b of the skirt wall 12 that contacts the outer wall 23 of the cap body 20. In this case, as shown in Fig. 4, the radial groove width W1 of the first water guiding groove 31 is set to be narrower than the gap GP1 of the narrow portion NP formed by the outer wall 23 of the cap body 20 and the inner end 12c of the lower end surface 12b of the skirt wall 12. As a result, as will be described in detail later, liquid that has seeped in through the gap between the top cover 10 and the cap body 20 can be attracted into the first water guiding groove 31 (on the circumference of the skirt wall 12), where a relatively strong capillary phenomenon occurs, rather than toward the narrow portion NP. The radial groove width W1 of the first water guide groove 31 may be set to be the narrowest in the path of the shower water that leads to the fitting portion FP.

[0037] As shown in Fig. 1 and other figures, the first water guide groove 31 in this embodiment is preferably formed in an annular shape on the lower end surface 12b of the skirt wall 12 for reasons such as the stable development of capillary action. While the first water guide groove 31 in this embodiment is a continuous annular groove along the circumferential direction on the lower end surface 12b of the skirt wall 12, it may instead be formed as a group of multiple discontinuous grooves along the circumferential direction on the lower end surface 12b, or may have a serpentine shape along the circumferential direction, such as a wavy or jagged (sawtooth) shape, as long as it exhibits the water guide effect described above. The depth of the first water guide groove 31 may be uniform along the circumferential direction, or it may vary in depth along the circumferential direction, for example, being deeper near the flange portion 15.

[0038] 4 and other figures, the axial upper end 31t of the first water guiding groove 31 in this embodiment is preferably positioned lower in the axial direction (Z direction) than the top cover undercut 14 and the main body undercut 24uc in the closed state in which the top cover 10 closes the dispensing tube 22. In this manner, in this embodiment, the first water guiding groove 31 is positioned so as not to affect the rigidity of the fitting portion FP without excessively increasing the number of fitting points between the top cover 10 and the cap main body 20. This prevents the top cover undercut 14 from becoming unintentionally flexible, and the water guiding effect of the first water guiding groove 31 can be achieved without affecting the fitting force of the fitting portion FP.

[0039] As shown in Figures 3 and 4, in the synthetic resin cap 100 of this embodiment, a space SP is formed between the narrow portion NP and the fitting portion FP. The space SP is a space below the fitting portion FP, surrounded by the outer peripheral surface of the bottom of the circumferential convex portion 24 of the cap body 20 and the inner surface of the skirt wall 12. The space SP may be formed, for example, by cutting out a portion of the skirt wall 12, by cutting out a portion of the outer peripheral surface of the bottom of the circumferential convex portion 24, or by cutting out both. Liquid that has entered the cap interior may, for example, in this embodiment, enter the space (gap GP3) between the first outer wall 23A and the second outer wall 23B after the water-conducting effect of the first water-conducting groove 31 decreases, and then enter the space SP through the narrow portion NP. In other words, the space SP can also function as a water-retaining space that can ultimately retain liquid that enters the cap interior without being attracted by the first water-conducting groove 31.

[0040] As shown in FIG. 4, in the closed state, the gap GP2 from the lower end 12d of the inner skirt wall surface forming the space SP to the outer peripheral surface of the base of the circumferential protrusion 24 where the main body undercut 24uc is provided is preferably wider in the radial direction than the spacing GP1 of the narrow portions NP (GP2 > GP1). This, in addition to the effect of the first water guide groove 31, further retains liquid that penetrates into the cap, thereby reducing its flow toward the inner periphery of the fitting portion FP. Furthermore, capillary action also prevents liquid from actively penetrating toward the inner diameter side of the fitting portion FP. In this case, the gap GP2 may be set larger than the radial groove width W1 of the first water guide groove 31.

[0041] Furthermore, the gap GP2 may be arranged to have a size equal to or larger than the gap GP3 between the first outer wall 23A and the second outer wall 23B. This causes a relatively stronger capillary phenomenon in the space between the first outer wall 23A and the second outer wall 23B than in the space SP, and the shower water that passes through the narrow portion NP and attempts to enter the gap GP2 can be attracted to the space between the first outer wall 23A and the second outer wall 23B.

[0042] The second water guide groove 32 is provided on at least one side of the skirt wall 12 and the circumferential protrusion 24. The second water guide groove 32 is located above the fitting portion FP between the upper cover undercut 14 and the main body undercut 24uc in the axial direction (Z direction). More specifically, the second water guide groove 32 of this embodiment is provided on the lower surface 17b of the inward protrusion 17 that protrudes radially inward from the inner circumferential surface of the skirt wall 12, as can be seen from Figures 3 and 4.

[0043] As described above, water ingress can occur when shower water is sprayed into the container during the process of filling the container with contents. When this occurs, shower water seeps into the cap from the first contact area FCA. However, since the synthetic resin cap 100 of this embodiment is equipped with the first water guide groove 31, the shower water is initially guided to the first water guide groove 31 rather than flowing into the narrow portion NP. However, if the amount of shower water entering the cap increases, the first water guide groove 31 alone may not be able to prevent the water from seeping in, and it may flow inward from the fitting portion FP via the narrow portion NP.

[0044] In contrast to this, the synthetic resin cap 100 of this embodiment may further be provided with the above-mentioned second water guide groove 32, and when such a second water guide groove 32 is provided, it becomes possible to further guide shower water that seeps in from the fitting portion FP to the inner side through the narrow portion NP into the second water guide groove 32.

[0045] 1, the second water guide grooves 32 in this embodiment are annular grooves that run continuously along the circumferential direction on the receiving surface (lower surface 17b) of the skirt wall 12 that comes into contact with the top surface 24t of the circumferential protrusion 24, but may be provided intermittently along the circumferential direction on the lower surface 17b as long as they provide the water guide effect described above. Providing the second water guide grooves 32 intermittently in the circumferential direction suppresses a decrease in rigidity of the inward protrusion 17, including the receiving surface (lower surface 17b), and prevents the receiving surface (lower surface 17b) and other parts from unintentionally deforming relative to the circumferential protrusion 24 when, for example, fitting the synthetic resin cap 100 onto the container or closing the lid.

[0046] In this embodiment, the second water guiding grooves 32 are provided axially above the first water guiding grooves 31. The radial groove width W2 of the second water guiding grooves 32 may be equal to or different from the radial groove width W1 of the first water guiding grooves 31, as long as capillary action can be exhibited. Furthermore, the axial depth of the second water guiding grooves 32 may be equal to the axial depth of the first water guiding grooves 31, as long as capillary action can be exhibited.

[0047] In the synthetic resin cap 100 according to this embodiment, firstly, the above-mentioned first water guiding groove 31 is provided on the lower end surface 12b of the skirt wall 12 (i.e., in the vicinity of the upstream side of the narrow portion NP), so even if water seeps into the inside of the cap from the first contact area FCA, which is the gap between the top lid and the cap body, the shower water will not flow directly into the narrow portion NP but will be guided into the first water guiding groove 31 (see FIG. 5). This makes it possible to prevent the shower water that has seeped into the inside of the cap from reaching the vicinity of the pouring tube.

[0048] Secondly, in the synthetic resin cap 100 of this embodiment, a space SP may be provided downstream of the narrow portion NP (opposite the first water guide groove 31), so that in such a case, shower water that passes through the narrow portion NP and seeps in can be retained in the space SP (see Figure 6). Furthermore, in the synthetic resin cap 100 of this embodiment, thirdly, a second water guide groove 32 may be provided on the downstream side of the space SP (opposite the narrow portion NP), so that in such a case, shower water that has also passed through the space SP can be retained in the second water guide groove 32 (see Figure 7).

[0049] According to the synthetic resin cap 100 of this embodiment described above, when shower water seeps into the inside of the cap, the capillary action of the first water guiding groove 31 attracts the shower water toward the first water guiding groove 31 rather than the narrow portion NP, thereby preventing the shower water from seeping deep into the inside of the cap. Furthermore, if the synthetic resin cap 100 is provided with the space SP and the second water guiding groove 32, it is possible to further effectively prevent the shower water that has seeped into the inside of the cap from reaching the vicinity of the dispensing tube 22.

[0050] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0051] For example, in the above-described embodiment, the water guiding groove 30 is provided on the lower end surface 12b of the skirt wall 12 and the lower surface 17b of the inward protrusion 17. However, the present invention is not limited to the above-described embodiment, and for example, the first water guiding groove 31 may be provided on the upper surface of the outer wall 23 instead of the lower end surface 12b, or the first water guiding groove 31 may be provided on both the lower end surface 12b of the skirt wall 12 and the upper surface of the outer wall 23. In this way, the above-described first water guiding groove 31 may be located on either the upper cover side or the cap body side, or may be located at any position other than the lower surface 17b of the skirt wall 12 before reaching the fitting portion FP, as long as it does not interfere with the fitting portion FP.

[0052] Similarly, with regard to the second water guide groove 32, for example, the second water guide groove 32 may be provided on the top surface 24t of the circumferential convex portion 24 instead of the undersurface 17b, or the second water guide groove 32 may be provided on both the undersurface 17b of the skirt wall 12 and the top surface 24t of the circumferential convex portion 24. In this way, the above-mentioned second water guide groove 32 may be located on the upper lid side or the cap body side, or at any location downstream of the fitting portion FP, as long as it does not interfere with the fitting portion FP.

[0053] Furthermore, the first water guiding groove 31 and the second water guiding groove 32 may be provided, for example, one each on the lower end surface 12b and the lower surface 17b, or a plurality of water guiding grooves may be provided so that at least one of them forms a double ring or triple ring. Furthermore, the groove shape of the water guiding groove 30 may be a shape suitable for injection molding, or may be any shape formed using, for example, a known 3D modeling technique, as long as it can exhibit capillary action. [Industrial Applicability]

[0054] INDUSTRIAL APPLICABILITY The present invention is suitable for a synthetic resin cap that can prevent water from seeping into the vicinity of the pouring tube inside the cap even when shower water is sprayed during the process of filling the contents. [Explanation of symbols]

[0055] 100 Synthetic resin cap (hinge cap) 10 Top lid 11 Top plate 12 Skirt Wall 13 Inner ring 14 Upper lid undercut 15 Tsuba 16 Protrusion 20 Cap body 21 Top wall 22 Pour tube 23 Outer wall 24 Circumferential convex part 25 Second inner ring 26 Pull Ring 27 score 30 Water Channel 31 First Water Channel 32 Second Water Channel 40 Hinge joint

Claims

1. an upper cover having a top panel and a skirt wall descending from the periphery of the top panel; A synthetic resin cap including a cap body to be attached to a container opening, the cap body having a top wall, a pouring tube extending upward from the top wall, an outer wall descending downward from an outer peripheral edge of the top wall, and a body undercut that fits into an upper cover undercut formed on an inner peripheral surface of the skirt wall outside the pouring tube, a first water guide groove extending in the axial direction is formed on a lower end surface of the skirt wall that contacts the cap body; The radial groove width of the first water guide groove is a gap GP between the outer wall of the cap body and the lower end of the inner surface of the skirt wall. １ A synthetic resin cap characterized by being narrower than

2. 2. The synthetic resin cap according to claim 1, wherein the upper end of the first water guide groove in the axial direction is positioned lower in the axial direction than the upper cover undercut when the upper cover is in a closed state in which the upper cover closes the pouring tube.

3. In the closed state, a gap GP is formed between the lower end of the inner surface of the skirt wall and the outer peripheral surface of the bottom of the circumferential convex portion where the main body undercut is provided. ２ is the gap GP between the narrowed portions １ 3. The synthetic resin cap according to claim 2, wherein the width of the synthetic resin cap is wider in the radial direction than the width of the synthetic resin cap.

4. 4. The synthetic resin cap according to claim 3, wherein at least one of the skirt wall and the circumferential convex portion has a second water guide groove above the mating portion between the upper cover undercut and the main body undercut in the axial direction.

5. The synthetic resin cap according to claim 4 , wherein the second water guide grooves are provided intermittently along the circumferential direction on a receiving surface of the skirt wall that contacts the top surface of the circumferential convex portion.

6. The synthetic resin cap according to any one of claims 1 to 5, wherein the first water guide groove is formed in an annular shape on the lower end surface of the skirt wall.

7. An inner ring that engages with the pouring tube is formed on the top plate, 6. The synthetic resin cap according to claim 1, wherein the cap body and the upper lid are connected via a hinge joint.

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