JP7421910B2 - Plug-in synthetic resin cap - Google Patents

Description

The present invention relates to a stopper-type synthetic resin cap that is used by being fitted into a relatively wide-mouthed container such as a milk bottle, and more specifically, it is capable of being disposed of together with the container and is highly easy to open. The present invention relates to a cap with a different structure.

BACKGROUND ART Bottles with relatively large diameter spouts (hereinafter, such bottles are also referred to as "wide-mouth bottles") are known as containers for storing milk drinks such as milk. As a cap for sealing such a wide-mouth bottle, a cap having a structure as exemplified in Patent Document 1 is used, for example.

Glass has conventionally been suitably used as a material constituting the wide-mouth bottle described above, but in recent years, polyester resins such as PET have also come to be used from the viewpoint of weight reduction. Additionally, recently, used polyester resin bottles have been collected from the viewpoint of recycling.

On the other hand, Patent Document 2 proposes that in the above-mentioned recycling, by configuring the cap with the same material as the polyester resin bottle, the recycling process can be simplified without separating the collected bottle and the cap. ing.

JP2014-223933A Japanese Patent Application Publication No. 2000-256472

Caps for sealing not only the above-mentioned wide-mouthed bottles but also other containers are required to have both high sealing performance when sealed and ease of opening when opened. In this regard, in Patent Document 1 mentioned above, although the above-mentioned characteristics are achieved by using a relatively soft olefin resin such as polyethylene as the material constituting the cap, the cap is made of a material different from that of the container. Therefore, separate collection is required.

On the other hand, as exemplified in Patent Document 2, if the cap is made of the same material as the wide-mouth bottle, the above-mentioned separate collection is not necessary, but if the container is made of a relatively hard polyester material, The high sealing performance and ease of opening will deteriorate.

As described above, there is still room for improvement in the conventional technology including the above-mentioned patent documents, and therefore, as an example of the object of the present invention, it is possible to achieve both high sealing performance and ease of opening while eliminating the trouble of separate collection. An example of the present invention is to provide a plug-type synthetic resin cap having a structure.

In order to solve the above problems, a plugging type synthetic resin cap in one embodiment of the present invention has (1) a top wall and an intermittent portion that hangs down from the periphery of the top wall and extends upward from the bottom end. a plurality of skirt walls formed along a circumferential direction, a plurality of leg parts extending from the skirt wall so as to sandwich the intermittent part, and protruding inward in the radial direction of the skirt wall; The lower end is bent back to provide a bent part that can fit with the container opening , and the intermittent part is interrupted by the skirt wall along the circumferential direction so that the lower end of the skirt wall is in an intermittent shape. Thin-walled portions are formed above the intermittent portions and are arranged between the adjacent leg portions to correspond to each other .

In the plug-type synthetic resin cap described in (1) above, (2) a flange portion that projects radially outward is formed on the outer peripheral surface of the skirt wall above the bent portion. It is preferable that the

Further, in the stopper type synthetic resin cap described in (1) or (2) above, (3) it is preferable that the leg portions do not extend from the skirt wall below the flange portion.

Further, the stopper type synthetic resin cap according to any one of (1) to (4) above further includes (5) an inner ring that hangs down from the top wall inside the skirt wall, and the inner ring Preferably, the lower end of the skirt wall is located above the bent portion of the skirt wall.

In the plug-type synthetic resin cap according to any one of (1) to (5) above, (6) the plate thickness t2 at the bent portion of the leg portion is greater than the thickness t2 of the leg portion other than the bent portion of the skirt wall. It is preferable that the thickness is thinner than the plate thickness t1.

The plug-type synthetic resin cap described in any one of (1) to (6) above is preferably (7) a polyester resin having a melting point of 230°C to 270°C.

Furthermore, the stopperable synthetic resin cap described in any one of (1) to (7) above is preferably made of the same material as (8) the container.

According to the stopper-type cap of the present invention, in addition to being able to recycle the container and the cap without separating them, it is also possible to achieve higher sealing performance and ease of opening.

It is an external perspective view of the stopper type synthetic resin cap in an embodiment. FIG. 3 is a top view of the stopper type synthetic resin cap seen from above. FIG. 3 is a bottom view of the stopper-type synthetic resin cap seen from below. FIG. 3 is a side view of the plugging type synthetic resin cap as seen from the X direction and the Y direction, respectively. 4 is a cross-sectional view taken along line AA in FIGS. 2 and 3. FIG. FIG. 3 is a schematic diagram showing the states of a stopper-type synthetic resin cap when the cap is closed and when the cap is opened. FIG. 3 is a cross-sectional view of a plugging type synthetic resin cap fitted to the mouth of the container. It is a state transition diagram when molding the leg part of a stopper type synthetic resin cap.

Embodiments for suitably implementing the present invention will be described below.
In this embodiment, for convenience of explanation, the X, Y, and Z directions are appropriately set in the explanation using the figures, but this is for convenience of explanation and does not limit the present invention excessively.

≪Plug-type synthetic resin cap 100≫
First, the structure of the stopper type synthetic resin cap 100 according to the present embodiment will be described with reference to FIGS. 1 to 7.
As shown in FIG. 1 and the like, the plugging type synthetic resin cap 100 of the present embodiment has a function of fitting into a container opening 201 of a container 200, which will be described later, by plugging. The skirt wall 20 is configured to include at least a skirt wall 20 that hangs down from the peripheral edge of the face wall 10 along the axial direction (in the illustrated Z direction).

Here, as the container 200 suitable for this embodiment, for example, a wide mouth bottle with a relatively wide spout as shown in FIG. 6 can be exemplified. Note that the container 200 is not limited to the wide-mouth bottle described above, but may be a bottle of a general diameter for storing soft drinks, tea, etc. Furthermore, as the material of the container 200, polyester resin such as polyethylene terephthalate (PET) resin is preferable.

The contents stored in the container 200 are not particularly limited, and various known liquids such as milk drinks such as milk and soft drinks such as tea can be used. Further, as the contents stored in the container 200, in place of the various liquids described above, a known solid material such as a drug or food such as a tablet, or a known semi-solid material in the form of a gel may be used.

The plugging type synthetic resin cap 100 of this embodiment is preferably made of the same material as the container 200 from the viewpoint of improving the convenience of recycling as described above. For example, if PET resin (polyester resin) having a melting point of 230° C. to 270° C. is used as the material for the container 200, the plug-type synthetic resin cap 100 made of the same PET resin (polyester resin) is used. Preferably.

Although PET resin is suitable for the beverage container, for example, if the container 200 is used for purposes other than beverages, general-purpose resins or engineering plastics other than PET resin may be used. Even in this case, the convenience of recycling can be improved by applying the stopper type synthetic resin cap 100 made of the same material to such a container 200 as a so-called single material.

As understood from FIGS. 3 and 4, the skirt wall 20 of this embodiment has intermittent portions 23 extending upward from the lower end in the circumferential direction (θz direction) so that the lower end thereof is intermittent. Multiple locations are provided intermittently along the route. Further, as shown in FIG. 3, in this embodiment, the lengths in the circumferential direction of the intermittent portions 23 formed intermittently are configured to differ approximately corresponding to the thin portions 24 described later.

However, the circumferential length of the intermittent portions 23 can be set as appropriate depending on the required opening force, the thin wall portion 24, etc. For example, the circumferential lengths of the intermittent portions 23 formed intermittently can be set equally. Alternatively, the length may be set to be shorter than the length of the thin portion 24 in the circumferential direction, or may be set independently of the thin portion 24 .

Further, as shown in FIGS. 3 and 4, in the stopper type synthetic resin cap 100 of this embodiment, a plurality of leg portions 21 extend from the skirt wall 20 so as to sandwich the intermittent portion 23 described above. In this embodiment, a total of eight plugs are formed along the circumferential direction of the plugging type synthetic resin cap 100, but any number other than eight may be used.

As described above, in this embodiment, a plurality of legs 21 are provided around the axis (θz) of the stopper type synthetic resin cap 100. The lengths L1 of these legs 21 in the circumferential direction may be approximately equal to each other, or the legs 21 may have different lengths in the circumferential direction. For example, the length L1 of each of the plurality of legs 21 in the circumferential direction may be changed as it approaches the flange 30 (for example, it becomes shorter as it approaches the flange 30). Thereby, the fitting force of the plugging type synthetic resin cap 100 to the container 200 can be changed in the circumferential direction.

Further, in this embodiment, the legs 21 extending from the skirt wall 20 so as to sandwich the intermittent portion 23 are all bent back so as to protrude inward in the radial direction of the skirt wall, but the present invention is not limited to this embodiment. That is, at least one of the extended leg portions 21 may not be bent back, or this portion may be omitted so that it does not extend.

Further, the height h2 of the leg portion 21 in the axial direction may be appropriately set according to the height h1 of the entire skirt wall 20 of the stopper type synthetic resin cap 100 in the axial direction.
For example, considering the shape of the container mouth 201, the height h2 of the leg 21 described above is preferably less than half the height h1 of the entire skirt wall 20. As a result, a relatively large portion of the container mouth 201 can be covered by a majority of the axial height (h1) of the entire cap, which can be more effective in terms of hygiene of the container mouth 201 when the cap is closed.

As is clear from the comparison with FIGS. 3 and 4, the legs 21 do not extend from the skirt wall 20 below the collar 30 (described later). This makes it easy for the user of the container 200 to hook his or her fingers onto the flange 30, and also prevents the fitting force with the container opening 201 from becoming excessive. Therefore, in this embodiment, it can be said that the intermittent part 23 is provided also below the collar part 30.

The intermittent portion 23 located below the flange portion 30 is designed such that its length in the circumferential direction is longer (larger) than other intermittent portions 23 (intermittent portions 23 located between adjacent leg portions 21). ) is configured.
Note that the length of the intermittent portion 23 in the axial direction (Z direction) may be set as appropriate depending on the required opening force, since it affects the bending of the stopper-type synthetic resin cap 100 when the cap is opened.

Further, as shown in FIG. 4 and the like, in the plugging type synthetic resin cap 100 of this embodiment, a thin portion 24 is formed above the above-mentioned intermittent portion 23. The thin portions 24 are provided intermittently along the circumferential direction on the outer circumferential surface 20a of the skirt wall 20, and are arranged so as to correspond between adjacent leg portions 21.
Such thin wall portion 24 is a region of the skirt wall 20 that is thinner than other portions, and has the function of causing the stopper type synthetic resin cap 100 to bend when the cap is opened. There is. That is, as shown in FIGS. 5 and 7, the plate thickness t3 in the thin portion 24 is formed to be thinner than the normal plate thickness t1 in other parts of the skirt wall 20.

As shown in FIG. 2, the lengths L2 in the circumferential direction of the plurality of thin parts 24 provided in the skirt wall 20 are not all the same but different in this embodiment. That is, the length L2 of the thin portion 24 located next to the flange 30 is set to be shorter than the length L2 of the thin portion 24 located not adjacent to the flange 30. This prevents the above-mentioned opening force during opening from becoming excessively large.
Note that the lengths L2 of the plurality of thin portions 24 in the circumferential direction are just one example, and, for example, the lengths L2 of the plurality of thin portions 24 may be set to be substantially equal to each other.

<Bending portion 22>
Next, the bent portion 22 provided in the plugging type synthetic resin cap 100 of this embodiment will be described in detail. As shown in FIGS. 6 and 7, the stopper-type synthetic resin cap 100 of this embodiment has the lower end 21a of the leg 21 extending from the skirt wall 20 bent back so that it fits into the container opening 201. A possible bend 22 is provided.

As shown in FIG. 6, the bent portion 22 has a function of engaging with an engaging step portion 202 formed on the container mouth portion 201. The bent portion 22 is formed by bending the lower end 21a of the leg portion 21 radially inward (toward the inner circumferential surface 20b of the skirt wall 20), but the shape of the bent portion 22 is as described above. It is not limited to the form.

That is, the bent portion 22 of this embodiment can be modified in various ways as long as it has the function of engaging with the above-mentioned engagement step portion 202. For example, in the bent portion 22, the lower end 21a of the leg portion 21 may be bent back toward the outside in the radial direction (toward the outer circumferential surface 20a of the skirt wall 20), and the bent portion may be inclined toward the inside in the radial direction.

In addition, as another form of the bent portion 22, the lower end 21a of the leg portion 21 does not necessarily have to be bent back upward, and for example, the portion of the leg portion 21 located above the lower end 21a is radially inward or radially It may be configured to be able to curve outward and engage with the engagement step portion 202 . At this time, similarly to the above, in the case where the portion of the leg portion 21 located above the lower end 21a is curved radially outward, this curved portion is further inclined radially inward.

As shown in FIGS. 6 and 7, the bent portion 22 of this embodiment has a curled shape in which the lower end 21a of the leg portion 21 described above is curled upward (the bent portion is gently curved as a whole). shape) is preferable. However, in this embodiment, the bent portion 22 does not necessarily have to be in the above-described curled shape, and may be in a form in which the lower end 21a of the leg portion 21 is folded upward inwardly or outwardly. At this time, the position of the upwardly curled lower end 21a in the axial direction is preferably located below the flange 30, which will be described later.

Moreover, as shown in FIG. 7, it is preferable that the plate thickness t2 of the bent portion 22 of the leg portion 21 described above is thinner than the plate thickness t1 of the skirt wall 20 other than the bent portion 22. This makes it possible to form the bent portion 22 efficiently. Note that the bent portion 22 also requires a strength sufficient to be able to engage with the above-mentioned engagement step portion 202 and seal the container mouth portion 201. It is desirable that the thickness t2 is greater.

<Brim section 30>
Next, the flange 30 provided in the stopper type synthetic resin cap 100 of this embodiment will be described in detail. As shown in FIGS. 1, 2, and 5, in the plugging type synthetic resin cap 100 of this embodiment, a flange portion 30 that projects radially outward is formed on the skirt wall 20.

As is clear from these figures, the collar portion 30 of this embodiment is preferably provided above the bent portion 22 in the outer circumferential surface 20a of the skirt wall 20 in the axial direction. Thereby, the user can remove the stopper-type synthetic resin cap 100 from the container opening 201 without requiring excessive force to open the cap.

Note that the position of the collar portion 30 in the axial direction may be changed as appropriate depending on the design value of the above-mentioned opening force. As shown in FIG. 5 and the like, the plugging type synthetic resin cap 100 further includes an inner ring 11 that hangs down from the bottom surface 10b of the top wall 10 inside the skirt wall 20. This inner ring 11 has a function of sealing the contents of the container 200 by engaging with the inner peripheral surface of the container opening 201 when the container is closed.

Therefore, in the plug-type synthetic resin cap 100 of this embodiment, in view of sealing performance and ease of opening, the lower end 11a of the inner ring 11 is located above the bent portion 22 of the skirt wall 20 in the axial direction. It is preferable that the At this time, as shown in FIG. 5, it is more preferable that the height h3 of the inner ring 11 from the bottom surface 10b is equal to or less than the height h2 of the leg portion 21 in the axial direction.

<Condition when closed and opened>
Next, using FIG. 6, the state when the stopper type synthetic resin cap 100 is closed to the container 200 and the state when the stopper type synthetic resin cap 100 is removed from the container 200 will be explained. .

First, when sealing the contents of the container 200, the container opening 201 is plugged with a stopper-type synthetic resin cap 100. That is, no screws or the like are formed on the inner circumferential surface 20b side of the skirt wall of this embodiment, and when the stopper type synthetic resin cap 100 is placed on the upper surface of the container opening 201, the upper surface of the top wall 10 is Press 10a.

Since the inscribed circle of the plurality of bent portions 22 formed along the circumferential direction is smaller than the outer diameter of the container mouth portion 201, the bent portions 22 are pushed over the container mouth portion 201 by the above-described pressing operation to the outside in the radial direction. deforms elastically. Thereafter, the bent portion 22 gets over the container mouth portion 201 and then engages with the engagement step portion 202 . At this time, the inner ring 11 formed on the bottom surface 10b of the top wall 10 engages with the inner peripheral surface of the container opening 201, thereby sealing the contents.

At this time, as shown in the figure, in the stopper type synthetic resin cap 100 of the present embodiment, a thin portion 24 is formed on the outer peripheral surface 20a of the skirt wall 20, and an intermittent portion 23 is formed up to the vicinity of the top wall 10. It has not been. Thereby, by covering the upper end portion of the container mouth portion 201 with the thin wall portion 24, it is possible to protect the upper end portion from outside air, dust, and the like.

On the other hand, when opening a bottle, the user may, for example, hook his or her finger onto the flange 30 of the stopper-type synthetic resin cap 100 to turn up the stopper-type synthetic resin cap 100 from the container opening 201. conduct. Here, for example, if the stopper-type synthetic resin cap 100 is made of the same resin as the container 200 (such as PET resin), it is more rigid than a cap made of olefin resin, so it is difficult to open many applications. It is assumed that a stopper will be required.

In contrast, according to the plugging type synthetic resin cap 100 of the present embodiment, the leg portions 21 can be elastically deformed radially outwards relatively easily due to the plurality of thin portions 24 and the plurality of bent portions 22 described above. It is possible. As shown in FIG. 6, in the present embodiment, the thin wall portion 24x, on which the tensile force in the circumferential direction is applied when the user lifts the collar portion 30 when opening the bottle, has a lower thickness than the other thin wall portions 24. It is preferable that the width is set so as to increase the length in the circumferential direction. As a result, when opening the cap as described above, the wide thin portion 24x easily stretches in the circumferential direction, and smooth opening can be realized.

As a result, when the stopper-type synthetic resin cap 100 is turned up from the container opening 201, the wide thin wall portion 24 is easily elastically deformed, and the leg portion 21 is displaced radially outward (elastic deformation). ) has become easier.
Further, as is clear from FIGS. 3 and 4, in this embodiment, a convex portion 31 may be formed on the bottom side of the collar portion 30. This allows the user to easily hook his or her fingers through the convex portion 31 of the collar portion 30.

<Method for forming bent portion 22>
Next, an example of a method for forming the bent portion 22 will be described using FIG. 8.
As described above, the bent portion 22 of the plugging type synthetic resin cap 100 does not need to be curled as long as it has the function of engaging with the engagement step portion 202.

That is, as shown in "before curling" in the same figure, first, parts other than the bent portion 22 are formed by injection molding or the like as primary molding. At this time, long leg portions 25 extending downward in the axial direction are provided intermittently along the circumferential direction on the lower end side of the skirt wall 20. Note that the above-mentioned intermittent portion 23 is already provided between the long leg portions 25.

Next, as secondary molding, each long leg portion 25 can be curled toward the inner circumferential surface 20b of the skirt wall 20, for example, as shown in the figure. As such a curling method, for example, a known curling machine disclosed in Japanese Patent Publication No. 1983-502265 can be used. That is, after first heating and softening the long leg portions 25, the plurality of bent portions 22 can be molded at once by using the above-described known curl molding machine or the like. Note that the above is just an example, and the bent portions 22 may be formed by individually deforming the long leg portions 25 while preheating them without using such a curling machine.

The present embodiment described above is particularly effective when the container and the cap are made of a single material of polyester resin such as PET resin.
That is, when the container and the cap fit together, it is preferable to form undercuts (protrusions for fitting with the container) on the inner ring 11, the inner circumferential surface 20b of the skirt wall 20, etc., as in the conventional structure. When injection molding is performed using polyester resin such as PET resin, mold release becomes difficult or the mold must be complicated.

Furthermore, since PET resin (polyester resin) has a poor flow of resin into an injection mold compared to olefin resin, it is possible that the resin may not be properly distributed in the mold, resulting in molding defects. In this way, if a plugging type cap is to be constructed from the same polyester resin as the container 200, consideration must be given to ease of injection molding and suppression of molding defects in consideration of cost.

According to the stopper type synthetic resin cap 100 of this embodiment, firstly, by using the same material as the container 200, the container and the cap can be recycled without having to be separated. Secondly, according to this plugging type synthetic resin cap 100, the outer peripheral surface 20a of the skirt wall 20 is provided with a plurality of thin parts 24, and the lower end of the skirt wall 20 is a leg part 21 having a bent part 22. This makes it possible to simultaneously achieve high sealing performance and ease of opening.

Note that the embodiment described above is an example, and various modifications can be made without departing from the spirit of the present application. For example, although the inner ring 11 is provided on the top wall 10 of the plugging type synthetic resin cap 100, instead of or in addition to this, a rubber member such as a known packing may be provided on the bottom surface 10b of the top wall 10. good.

Further, the height h2 of the inner ring 11 described above is an example, and may be changed as appropriate depending on the design value of the opening force in consideration of the fitting force with the container 200. Further, an undercut may be further formed on the outer wall of the inner ring 11 that contacts the container 200 to a degree that allows safe mold release during injection molding.

Further, in the above-described embodiment, the thin wall portion 24 is disposed above the intermittent portion 23 in the axial direction, and the thin wall portion 24 is configured to have a longer height in the axial direction than the intermittent portion 23. Ta. However, the present invention is not limited to this embodiment, and the height h2 of the intermittent portion 23 in the axial direction may be set to be greater than or equal to the height of the thin portion 24 in the axial direction.

Further, in the present embodiment, the thin wall portion 24 is formed along the circumferential direction on the outer circumferential surface 20a of the skirt wall 20, but this thin wall portion 24 is not formed, and for example, the same plate as other portions of the skirt wall 20 is formed. The thickness may be t1 and the thin portion 24 may be omitted. Alternatively, the thin wall portion 24 may be omitted and the intermittent portion 23 may be provided up to the vicinity of the upper end of the top wall 10 if this is permissible in terms of hygiene of the container mouth portion 201 or injection molding during cap manufacturing.

Furthermore, the synthetic resin cap may be constructed by appropriately combining known elements with respect to the above-described embodiments without departing from the spirit of the present invention.

INDUSTRIAL APPLICABILITY The present invention is suitable for realizing a plug-type cap that has high sealing performance and ease of opening while improving the convenience of recycling.

100: Plug-in type synthetic resin cap 10: Top wall 20: Skirt wall 21: Leg portion 22: Bent portion 23: Intermittent portion 30: Flange portion 200: Container 201: Container mouth portion 202: Engagement stepped portion

Claims (7)

A ceiling wall,
a skirt wall in which a plurality of intermittent parts are formed along the circumferential direction, hanging from the peripheral edge of the top wall and extending upward from the lower end;
A plurality of leg portions extend from the skirt wall so as to sandwich the intermittent portion,
The lower ends of the legs are bent back so as to protrude inward in the radial direction of the skirt wall, and are provided with bent portions that can fit with the container opening ;
The intermittent portion is provided intermittently on the skirt wall along the circumferential direction so that the lower end of the skirt wall is in an intermittent shape,
The stopper-type synthetic resin cap is characterized in that thin-walled portions are formed above the intermittent portions to correspond to each other between the adjacent leg portions . 2. The stopper-type synthetic resin cap according to claim 1, wherein a flange portion projecting radially outward is formed above the bent portion on the outer circumferential surface of the skirt wall. The stopper-type synthetic resin cap according to claim 1 or 2, wherein the leg portion does not extend from the skirt wall below the flange portion. further comprising an inner ring hanging from the top wall inside the skirt wall,
The plug-type synthetic resin cap according to any one of claims 1 to 3 , wherein the lower end of the inner ring is located above the bent portion of the skirt wall. The stopper-type synthetic resin cap according to any one of claims 1 to 4 , wherein a plate thickness t2 at the bent portion of the leg portion is thinner than a plate thickness t1 of the skirt wall other than the bent portion. The plug-type synthetic resin cap according to any one of claims 1 to 5 , which is a polyester resin having a melting point of 230°C to 270°C. The stopper-type synthetic resin cap according to any one of claims 1 to 6 , which is made of the same material as the container.