JP2012071844A - Hinge cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hinge cap, in which a cap body is connected to a top cover by using a hinge band and two strap bands and a whitening phenomenon of the strap band, which is caused by the opening and closing of the top cover, is effectively prevented.SOLUTION: The hinge cap comprises the cap body 1, which is fitted/fixed to a mouth part of a container and includes a cylindrical side wall 7, and the top cover 3 connected to the cylindrical side wall 7 of the cap body 1 via the hinge band 23 and two strap bands 25, 25. The hinge band 23 is connected to the upper end of the cylindrical side wall 7, and the strap bands 25 are positioned on both-side parts of the hinge band 23 in the peripheral direction and connected to the outside surface of the cylindrical side wall 7 at the positions lower than that of the hinge band 23. The thickness of the joined portion of the strap band 25 to the outside surface of the cylindrical side wall 7 is made thinner gradually toward the end on a hinge band 23 side from the end parted from the hinge band 23 side.

Description

  The present invention relates to a hinge cap including a cap body that is fitted and fixed to a container mouth portion, and an upper lid that is hinged to the cap body.

  A hinge cap in which an upper lid is hinge-connected to a cap body attached to a container mouth portion has an advantage that a component is a one-piece and can be molded by one molding. Also, when opening the upper lid and taking out the container contents, the upper lid does not separate from the cap body and is integrally connected to the cap body, so there is an advantage that the container contents can be easily taken out, For example, it is widely used as a cap for containers filled with various seasonings.

By the way, in such a hinge cap, the upper lid is generally connected to the cylindrical side wall of the cap body by a wide hinge band and two strap bands arranged near both sides of the hinge band. The hinge band joins the upper end portion of the cylindrical side wall and the lower end portion of the skirt wall of the upper lid, and the two strap bands are respectively positioned at a position lower than the hinge band and the cylindrical side wall and the skirt wall. The outer surface is joined (refer patent document 1).
When the cap main body and the upper lid are connected by such a hinge band and a strap band, for example, when the upper lid that closes the cap main body is swung open by hand, the tension acting on the hinge band When the upper lid is kept in a moderately open state, and when the upper lid is further swung open, the upper lid is pulled in the direction of further opening due to the tension acting on the strap band. The state in which the upper lid is largely opened is maintained, and the container contents can be easily taken out by opening the upper lid.

JP 2007-302291 A

However, in the hinge cap in which the upper lid is hinge-connected to the cap body as described above, there is a problem that when the upper lid is repeatedly opened and closed, the hinge band and the strap band are likely to be whitened. That is, whitening occurs across these bands, which not only impairs the appearance of the cap, but also becomes brittle due to whitening, and in extreme cases, these bands peel and further break. It sometimes happened. In particular, there is a tendency that two strap bands are likely to be whitened. When whitening occurs in the strap band, the band is narrow in width, so that the band is particularly easily peeled off and ruptured. .
In recent years, in order to improve separation and disposal, a cylindrical wall of the cap body having a double wall structure of an inner wall and an outer wall has been widely used. In the hinge cap which has, there exists a tendency for the above whitening phenomenon to become remarkable.

Accordingly, an object of the present invention is to effectively prevent whitening phenomenon in the strap band caused by opening and closing of the upper lid in the hinge cap in which the cap body and the upper lid are connected by the hinge band and the two strap bands. It is to provide a hinge cap.
Another object of the present invention is to provide a hinge cap in which the whitening phenomenon in the hinge band is effectively prevented.

According to the present invention, from a cap body fitted and fixed to a container mouth portion and having a cylindrical side wall, and an upper lid connected to the cylindrical side wall of the cap body via a hinge band and two strap bands. The hinge band is connected to the upper end of the cylindrical side wall, and the strap band is located on both sides in the circumferential direction of the hinge band and is lower than the hinge band at the outer surface of the cylindrical side wall. In the hinge cap connected to
The thickness of the portion of the strap band joined to the outer surface of the cylindrical side wall gradually decreases from an end portion away from the hinge band side toward an end portion of the hinge band side. A hinge cap is provided.

According to the present invention, there is also provided a cap body fitted and fixed to the container mouth portion and provided with a cylindrical side wall, and an upper lid connected to the cylindrical side wall of the cap body via a hinge band and two strap bands. The hinge band is connected to the upper end of the cylindrical side wall, and the strap band is located on both sides in the circumferential direction of the hinge connecting portion and at a position lower than the hinge band. In the hinge cap connected to the outer surface of
In a state where the upper lid is opened and inverted, a side cross section of the strap band is a first base portion extending horizontally from the outer surface of the cylindrical side wall to the upper lid side, and a cylindrical shape from the outer surface of the upper lid. A second base portion extending horizontally on the side wall, and the first base portion and the second base portion are connected to the horizontal bridging portion via an upward or downward stepped portion, respectively. A hinge cap characterized in having a shape is provided.

In the hinge cap of the present invention,
(1) In the state in which the upper lid is opened and inverted, a groove having an inverted V shape when viewed from a side cross section is formed on the lower surface of the hinge band. The surface extending in the width direction of the band so as to cross and the surface extending from the groove toward the upper lid side is a horizontal plane perpendicular to the cap axis,
Are preferred, and
(2) The joining line between the lower surface of the hinge band and the outer surface of the cylindrical side wall is located on a horizontal plane perpendicular to the cap axis,
Is preferred.
In the hinge cap of the present invention,
(3) The cylindrical side wall of the cap body has a double wall region that is divided into an inner side wall and an outer side wall by a slit whose thickness portion extends downward from the upper end. The hinge band and the strap band are connected to the outer wall of the wall region;
Is the best.

  In the hinge cap of the present invention, the thickness at the portion where the strap band and the cylindrical side wall outer surface of the cap body join (that is, the joint portion on the cap body side) gradually decreases toward the hinge band side. Thus, even when the upper lid is repeatedly opened and closed, whitening of the strap band can be effectively suppressed, and peeling and breaking of the strap band resulting from such whitening can be effectively prevented.

  According to the present invention, in a state where the upper lid is opened and inverted, a side cross section of the strap band is provided with a first base portion extending horizontally from the outer surface of the cylindrical side wall to the upper lid side, and the upper lid A second base portion extending in a horizontal direction from the outer surface to the cylindrical side wall, and the first base portion and the second base portion are respectively connected to the horizontal bridge via an upward or downward stepped portion. It can also be made into the shape which continued to the tangle. Even with such a side cross-sectional shape, it is possible to effectively suppress whitening of the strap band when the upper lid is repeatedly opened and closed, and to effectively prevent the strap band from being broken due to such whitening. Become.

  Furthermore, in the present invention, in order to effectively prevent whitening and peeling due to whitening and whitening in the hinge band, in the state where the upper lid is opened and reversed, A groove having an inverted V-shape when viewed in a side cross section is formed. The groove extends in the width direction of the band so as to cross the hinge band, and extends from the groove toward the upper lid side. It is preferable that the surface to be fixed is a horizontal plane perpendicular to the cap axis. Furthermore, the joining line between the lower surface of the hinge band and the outer surface of the cylindrical side wall is positioned on the horizontal plane perpendicular to the cap axis. Thus, the aspect in which the hinge band is joined to the cylindrical side wall has the greatest whitening prevention effect in the hinge band.

  As described above, in the present invention, whitening and detachment and breakage resulting from whitening in the strap band and the hinge band are prevented, so that the waste disposal can be achieved particularly by forming a double wall structure on the cylindrical side wall of the cap body. It is optimal to apply the present invention to a hinge cap with an increased height. The formation of such a double wall structure is most likely to cause whitening in a strap band or a hinge band. However, in the present invention, such whitening can be effectively prevented. .

The figure which shows the side surface cross section in the state which opened the upper cover in the suitable example of the hinge cap of this invention. The top view in the hinge cap of FIG. The side view in the hinge cap of FIG. The rear view which shows the hinge connection part side of the hinge cap of FIG. The figure which expands and shows the side cross section of the strap band in the hinge cap of FIG. The figure which expands and shows the part of the strap band in FIG. 4, and a part of hinge band. The top view which shows the flow-velocity distribution of the resin flow in the metal mold | die space corresponded to the strap band at the time of shape | molding the hinge cap of FIG. The figure which expands and shows the side cross section of the hinge band in the hinge cap of FIG. In other suitable examples of the hinge cap of this invention, the figure which shows the side surface cross section in the state which opened the upper cover. The top view in the hinge cap of FIG. The side view in the hinge cap of FIG. The rear view which shows the hinge connection part side of the hinge cap of FIG. The figure which expands and shows the side cross section of the strap band in the hinge cap of FIG. The rear view which expands and shows a part of strap band part in FIG. 12, and a part of hinge band.

  Referring to FIGS. 1 to 5, the hinge cap of the present invention includes a cap body 1 and an upper lid 3, and the cap body 1 is roughly suspended from a top plate portion 5 and a peripheral portion of the top plate portion 5. It is comprised from the cylindrical side wall 7 which is carrying out.

  On the lower surface side of the top plate portion 5, an inner ring 9 is formed extending downward with a space from the cylindrical side wall 7. Further, an engaging protrusion 8 is provided on a lower portion of the inner surface of the cylindrical side wall 7. That is, the container mouth is fitted into the space between the inner ring 9 and the cylindrical side wall 7 and the engaging projection 8 engages with the outer surface of the container mouth, whereby the cap body 1 It is attached to and firmly fixed.

  Further, the central portion of the top plate portion 5 is a concave concave portion, and an endless score 10 for forming a dispensing opening is formed on the peripheral portion thereof, on the upper surface side of the top plate portion 5. Is provided with a pull ring 11 for breaking the score via a support column 13. That is, when the pull ring 11 is pulled, the score 10 is broken, and an opening for pouring out the contents is formed in the top plate portion 5.

  Further, on the upper surface side of the top plate portion 5, a cylindrical projection 15 for guiding the pouring liquid is formed so as to surround the score 10, and the content liquid poured out through the pouring opening is It is guided by this cylindrical projection 15. The upper end of the cylindrical protrusion 15 spreads in a trumpet shape to improve the liquid drainage, and the liquid can be discharged smoothly. As can be understood from FIG. On the connecting portion side (hinge connecting portion) with the upper lid 3 which will be described later, the cylindrical projection 15 is formed with a low height so that the upper lid 3 is not obstructed from turning when the upper lid 3 is closed. Further, a circumferential protrusion 17 for holding the upper lid 3 is formed outside the cylindrical protrusion 15.

  Further, as shown in FIGS. 1 and 2, the cylindrical side wall 7 of the cap body 1 is divided into an inner side wall 7a and an outer side wall 7b by an arcuate slit 20 extending downward from the upper end. A double wall structure in which the inner side wall 7a and the outer side wall 7b are continuous at the lower end is formed. The inner side wall 7a and the outer side wall 7b are connected at the lower end thereof by a thin connecting portion 7c. Such a double wall structure is formed so that the cap body 1 after the container content liquid is poured out can be easily removed from the container mouth.

  The upper lid 3 is connected to the cylindrical side wall 7 of the cap body 1 (particularly, the outer wall 7b formed by the slit 20). That is, as can be understood from FIGS. 2 to 4, the cylindrical side wall 7 of the cap body 1 (with the central wide hinge band 23 and the two small strap bands 25, 25 located in the vicinity of both sides thereof. The outer wall 7b) and the upper lid 3 are connected.

  Further, in the vicinity of one strap band 25, an axial score 27 extending from the upper end to the lower end or the vicinity thereof is formed on the outer wall 7b. That is, when the upper lid 3 is opened and pulled down, the score 27 is torn and the outer wall 7b is broken, and then the torn outer wall 7b is rolled in the circumferential direction, The connecting portion 7c connecting the wall 7b and the inner wall 7a is broken, and as a result, only the inner wall 7a of the cap body 1 is fitted to the container mouth, and the fitting force is large. It falls, and it becomes possible to remove the cap main body 1 from a container opening | mouth part, without using a special tool.

  The upper lid 3 is formed by a top plate portion 31 and a skirt portion 33 extending from the periphery of the top plate portion 31.

  A circumferential projection 35 for sealing is formed on the inner surface of the top plate portion 31. That is, when the upper lid 3 is turned and closed, the circumferential protrusion 35 for sealing comes into close contact with the inner surface of the cylindrical protrusion 15 for guiding the liquid to be poured, and for this purpose, the score 10 is broken by the close contact. Sealability after opening is ensured.

  Further, a recessed portion 37 (see FIG. 1) is formed in a lower portion of the inner surface of the skirt portion 33 of the upper lid 3, and the protrusion at the upper end of the circumferential protrusion 17 described above is engaged with the recessed portion 37. The closed upper lid 3 is held stably.

Further, on the outer surface of the skirt portion 33 of the upper lid 3, an unsealing bar 40 is provided on the side opposite to the connecting portion side with the cylindrical side wall 7 of the cap body 1 described above. A flat protrusion 41 for preventing slipping is formed on the lower surface of the opening bag 40. When the opening lid 40 is hooked with a finger and the upper lid 3 is lifted upward, the engagement between the circumferential protrusion 17 and the concave portion 37 is released, and the upper lid 3 is opened.
As shown in FIG. 3, when the upper lid 3 is closed, a concave portion 43 is formed on the outer surface of the cylindrical side wall 7 (the outer surface of the outer wall 7b) in the lower portion of the portion where the opening bag 40 is located. The upper lid 3 can be easily opened by hooking a finger on the opening basket 40.

In the hinge cap having the above-described structure, the hinge band 23 that connects the cylindrical side wall 7 of the cap body 1 and the upper lid 3 has a center X of the cap body 1 and a center of the upper lid 3 as can be understood from FIG. 1 and 3, the hinge band 23 is connected to the upper end of the cylindrical side wall 7 (outer wall 7 b) and the lower end of the skirt portion 33, as shown in FIGS. 1 and 3. Has been. In FIG. 1, since the upper lid 3 is opened and inverted, the lower end of the skirt portion 33 is the upper end.
On the other hand, the two strap bands 25, 25 positioned at both ends in the circumferential direction of the hinge band 23 are respectively in the recesses 18 formed in the cylindrical side wall 7 (outer wall 7 b) at a position lower than the hinge band 23. And is connected to a recess 38 formed in the skirt portion 33 at a position higher than the hinge band 23 (see FIG. 3 with the upper lid closed). Further, since the strap band 25 is present at a position farther from the line Z connecting the center X of the cap body 1 and the center Y of the upper lid 3 than the hinge band 23, the strap band 25 is relatively more than the hinge band 23. The length of the side on the hinge band 23 side is short, and the length of the side opposite to the hinge band 23 side is long.

  When the upper lid 3 connected to the cylindrical side wall 7 (outer wall 7b) is pivoted and opened by the hinge band 23 and the two strap bands 25, 25, first, the upper lid 3 and the cap body 1 are first engaged. The engagement of the mating protrusion 17 is released, but at this time, the upper lid 3 is pulled by the relatively short tension of the hinge band 23, thereby maintaining an appropriate open state of the upper lid 3. When the upper lid 3 is further swung, the space between the cylindrical side wall 7 and the skirt portion 33 at the portion where the strap bands 25, 25 are connected increases, and as a result, a large tension is applied to the strap band 25. As a result, the upper lid 3 is largely opened, and even if the hand is released from the upper lid 3, the upper lid 3 is maintained in a largely opened state, so that the content liquid can be easily poured out by tilting the container. It has become.

The hinge cap having the structure described above is manufactured by injection molding using various thermoplastic resins, and as shown in FIG. 1, the upper lid 3 is opened and molded into an inverted shape. .
As the thermoplastic resin to be used, an olefin resin, particularly polyethylene is used from the viewpoint of satisfying the elasticity and flexibility required for the hinge cap and having good moldability, and most preferably linear. Low density polyethylene is used.

  In the hinge cap of the present invention, it is important to provide a thickness distribution on the side of the connecting portion of the strap bands 25, 25 with the cylindrical side wall 7 (outer wall 7b). This makes it possible to effectively prevent whitening when repeated opening and closing is performed.

That is, as shown in the side sectional view of FIG. 5, each strap band 25 has an appropriate curvature at the joint between the cylindrical side wall 7 (outer wall 7 b) of the cap body 1 and the skirt portion 33 of the upper lid 3. The strap band 25 is smoothly connected to the cylindrical side wall 7 and the skirt portion 33, and the central portion of the strap band 25 has a constant thickness t.
However, in the present invention, as shown in the enlarged rear view of FIG. 6, the thickness of the two strap bands 25 at the portion joined to the outer surface of the cylindrical side wall 7 (outer wall 7b) is hinged. A remarkable feature is that the thickness gradually decreases toward the band 23 side. As a result of such thickness distribution, as can be understood from FIG. 6, the joining line 51 in which the lower surface of the strap band 25 is joined to the outer surface of the cylindrical side wall 7 in the state where the upper cover is opened is It appears as an inclined line that gradually rises.

  Note that, as shown in FIG. 5, the joining line 51 is a line formed by a portion where a curvature surface that forms a joining portion with the cylindrical side wall 7 starts, and the curvature radius of the curvature surface. (R) becomes gradually smaller as it goes to the hinge band 23 side. In the embodiment, the radius of curvature is R1 (R = 1 mm) at the joint with the cylindrical side wall 7, the radius of curvature gradually decreases toward the hinge band 23 side, and the radius of curvature is R0 at the joint on the hinge band 23 side. .2 (R = 0.2 mm). Thereby, basically, the thickness of the strap band 25 at the joint portion becomes smaller toward the hinge band 23 side, but the thickness is constant at a portion away from the joint portion. (That is, the thickness t does not vary over the width direction and is a constant value). Further, in the state where the upper cover is opened, the joint portion between the lower surface of the strap band 25 and the skirt portion 33 does not vary in thickness in the width direction and has a constant value, and the curvature radius of the curvature surface is also constant. The joining line 53 is a horizontal line perpendicular to the axis L of the cap.

  In the present invention, the thickness distribution as described above is formed at the joint portion between the strap band 25 and the cylindrical side wall 7, so that whitening in the strap band 25 is effectively prevented. In particular, whitening in the vicinity of the joint with the cylindrical side wall 7 is remarkably prevented. Although the reason why whitening is prevented by such a thickness distribution has not been clearly clarified, the present inventors have suppressed orientation crystallization of the resin during cap molding, and furthermore, the upper lid 3 has been opened. It is thought that this may be due to the relaxation of the tensile stress applied to the strap band 25 at the time of closing.

  As described above, the hinge cap described above is molded in a state where the upper lid 3 is opened and inverted as shown in FIG. Specifically, a mold space having a space in which a hinge cap having the shape shown in FIG. 1 is formed is used, and a mold space corresponding to the cap body 1 (particularly a portion corresponding to the central portion of the top plate portion 5). The molten resin is injected by arranging an injection gate, and the resin passes through the mold space corresponding to the hinge band 23 and the strap band 25 and flows into the mold space corresponding to the upper lid 3. The molten resin filled in the space is cooled and solidified on the mold surface, whereby a hinge cap having a shape corresponding to the mold space is formed. When the hinge cap is molded in this way, the mold space corresponding to the strap band 25 is very narrow, so that the flow of the molten resin passing through this portion becomes uniform and is easily flow-oriented, and the molten resin is Because the mold space is narrow, it cools rapidly. As a result, in the portion where the strap band 25 is formed, the molecules are oriented and crystallized, and when the upper lid is opened and closed, the tensile stress concentrates on the aligned molecular chains, and thus whitening occurs by cutting the molecular chains. In an extreme case, it is considered that the strap band 25 peels and further breaks.

  However, according to the present invention, when the thickness of the portion of each strap band 25 joined to the outer surface of the cylindrical side wall 7 is gradually reduced toward the hinge band 23 side, the mold space corresponding to the strap band 25 is formed. It is considered that the velocity distribution of the resin flow when the resin is introduced is as shown in FIG. That is, the mold space corresponding to the strap band 25 (the cylindrical side wall 7 side) has a narrower mold space toward the hinge band 23 side, so that the introduction speed becomes slower. As the mold space increases toward the opposite side, the introduction speed is high. Therefore, in the mold space corresponding to the strap band 25, the resin flow that flows from the side opposite to the hinge band 23 flows toward the hinge band 23 as it goes to the outlet side (skirt portion 33 side). As a result, the resin flow in the mold space corresponding to the strap band 25 becomes turbulent and it is difficult for flow orientation to occur. Therefore, orientation crystallization of the resin is suppressed and the strap band 25 that has been cooled and solidified is cooled. The resin is isotropic and amorphous. Therefore, even if the upper lid 3 is repeatedly opened and closed, and tensile stress is applied, the molecular chain is not broken and the whitening at the strap band 25 is effectively avoided. .

  As described above, in the hinge cap of the present invention, whitening is prevented by suppressing orientation crystallization of the resin in the strap band 25 and relaxation of the tension applied to the strap band 25. Therefore, the strap band 25 is also ruptured due to whitening. Will be prevented.

  The degree of thickness distribution at the joint portion of the strap band 25 with the outer surface of the cylindrical side wall 7 differs depending on the width d (see FIG. 6) of the strap band 25 and cannot be generally defined. Considering that the width d of the strap band 25 formed on the hinge cap used for the container for beverages or beverages is about 2.0 to 2.5 mm, for example, the inclination angle θ of the joining line 51 with respect to the horizontal line is It is preferable to reduce the thickness on the hinge band 23 side so as to be about 10 to 15 degrees.

  Further, in order to impart appropriate elasticity and strength to the strap band 25, the thickness t is generally preferably in the range of about 0.4 to 0.6 mm.

  Furthermore, in the present invention, the form of the hinge band 23 is as shown in FIG. 8 in order to prevent whitening that occurs in the hinge band 23 when the opening and closing of the upper lid 3 is repeated.

That is, referring to the side sectional view of FIG. 8 (side sectional view at the cap centerline Z), an inverted V-shaped groove 60 is formed on the lower surface of the hinge band 23 with the upper lid opened. . The groove 60 is formed in a portion that can be bent when the upper lid 3 is closed, and extends in a straight line in the width direction of the band 23 so as to cross the hinge band 23. Further, a portion of the lower surface of the hinge band 23 on the side of the upper lid 3 (skirt portion 33) from the groove 60 is a horizontal plane 63 (that is, a plane perpendicular to the axis L of the cap). In the portion where is formed, the hinge band 23 has a flat plate shape with a constant thickness.
A groove 65 that is slightly recessed is formed on the upper surface of the hinge band 23 corresponding to the inverted V-shaped groove 60. As shown in FIG. 2, the groove extends in a straight line, leaving both ends slightly in the width direction of the upper surface of the hinge band 23, thereby making the hinge band 23 easy to bend. It is.

  In the hinge band 23 having the above-described form, as with the strap band 25, whitening that occurs when the upper lid 3 is repeatedly opened and closed is effectively prevented. The present inventors presume that the molding condition of the hinge band 23 when molding the cap is such that the orientation crystallization of the resin hardly occurs.

  The form for preventing whitening in the hinge band 23 is completely different from that of the strap band 25. This is because the circumferential width w (see FIG. 4) of the hinge band 23 is the strap band. This is probably because it is larger than 25 (usually about 11.5 to 12.00 mm) and has a different flow form of the molten resin during cap molding.

  Further, in the side sectional view with the upper lid shown in FIG. 8, the lower surface of the hinge band 23 gradually rises from the outer surface of the cylindrical side wall 7 (outer wall 7b) directly toward the upper lid 3 and then descends. Thus, an inverted V-shaped groove 60 is formed, but the distance between the outer surface of the cylindrical side wall 7 (outer wall 7b) and the outer surface of the skirt portion 33 is increased as the distance from the cap center line Z (see FIG. 2) increases. Will gradually spread. For this reason, in the side cross section of the hinge band 23 at a position away from the cap center line Z (see FIG. 2), the lower surface of the hinge band 23 once extends in the horizontal direction and then gradually rises toward the upper lid 3 side. 60 is formed.

  In the hinge band 23 of the above-described form, the depth of the inverted V-shaped groove 60 and the size of the horizontal surface 63 cannot be generally defined, but in general, the hinge band 23 at the portion where the groove 60 is formed. Is preferably about 50 to 70% of the thickness of the band at the joint between the hinge band 23 and the skirt 33, and the length q of the horizontal plane 63 is the radial length p of the hinge band 23. It is desirable that it is about 45 to 50%.

  Further, in the hinge band 23 of the form shown in FIG. 8, as shown in FIGS. 4 and 6, the joining line 23 a between the lower surface of the hinge band 23 and the outer surface of the cylindrical side wall 7 extends to the cap axis L. The hinge band 23 is most preferably joined to the cylindrical side wall 7 so as to be positioned on a plane perpendicular to the surface. In this case, the whitening prevention effect of the hinge band 23 is the greatest.

  That is, in such a joining form, the height from the cylindrical side wall 7 (outer wall 7b) is the same over the entire width direction of the hinge band 23. At the time of cap molding, the molten resin fills the mold space corresponding to the cylindrical side wall 7 and then flows into the mold space corresponding to the hinge band 23. It is considered that the inflow of the molten resin into the mold space is uniform over the entire width direction of the hinge band 23, and as a result, the above-described orientation crystallization is suppressed over the entire width direction of the hinge band 23.

For example, in the case where the joint portion at the center portion in the width direction of the hinge band 23 is located higher than the lower end of the cylindrical side wall 7 as compared with the peripheral portion thereof, As a result, the molten resin is not sufficiently blocked at the portion corresponding to the inverted V-shaped groove 60. The molten resin flows smoothly and becomes easy to flow-orientate, and the mold space corresponding to the inverted V-shaped groove 60 is extremely narrow, so that the molten resin is rapidly cooled at this portion. As a result, in such a case, orientation crystallization is likely to occur, and whitening is likely to occur partially.
However, if the joining line 23a is set as described above, the molten resin flows evenly over the entire width direction of the hinge band 23, so that orientation crystallization is reliably prevented and local whitening is also ensured. It becomes possible to prevent.

  In the hinge cap of the above-described embodiment, the strap band 25 is prevented from being whitened by changing the thickness so that the thickness of the strap band 25 gradually decreases toward the hinge band 23 side. By forming a step in 25, whitening in the strap band 25 can be effectively prevented. In particular, whitening of the entire strap band 25 can be prevented. Such a hinge cap is shown in FIGS.

  9 to 14, the hinge cap is the same as the hinge cap shown in FIGS. 1 to 8 except for the strap bands 25 and 25. Are indicated by the same imprinted numerals, and the description thereof is omitted.

  Referring to FIG. 11 showing the side of the hinge cap of this embodiment and FIG. 13 showing the side cross section of the strap band 25 in a state where the upper lid 3 is opened and inverted, the strap band 25 with the upper lid opened. Includes a first base 70 extending horizontally from the outer surface of the cylindrical side wall 7 (outer wall 7b) toward the upper lid 3 (skirt portion 33), and horizontally from the outer surface of the upper lid 3 toward the cylindrical side wall 7 side. The second base 71 extends, and the first base 70 and the second base 71 are connected to the horizontal bridging portion 75 through the stepped portions 73 and 73 facing upward, respectively. Have.

  That is, in the strap band 25 having such a side cross-sectional shape, compared to the distance D at the joint between the strap band 25 and the tubular side wall 7 and the joint between the strap band 25 and the skirt 33, Since the length of the strap band 25 in the radial direction is long, the tension applied to the strap band 25 when the upper lid 3 is opened and closed is relieved. As a result, the molecular chains of the resin in the strap band 25 are broken by such tension. Can be avoided, and the occurrence of whitening can be effectively prevented.

  In the strap band 25 having such a configuration, the degree of the steps 73 and 73, the lengths of the first and second base portions 70 and 71, and the length of the horizontal bridging portion 75 are the length of the strap band 25 in each cross section ( The radial length is preferably set to be about 10 to 15% longer than the distance D between the joint portions of the cylindrical side wall 7 and the skirt portion 33 in each cross section. If the strap band 25 becomes longer than necessary, the opening function of the upper lid 3 by pulling the strap band 25 is impaired, and if the length of the strap band 25 is close to the gap D, tension relaxation is not possible. This may be sufficient, and it may be difficult to effectively suppress whitening.

Further, it is believed that the shape as described above suppresses orientation crystallization of the resin in the strap band 25 when the hinge cap is formed. That is, at the time of forming the hinge cap, the molten resin that has flowed into the mold space corresponding to the strap band 25 collides with the mold surface that forms the stepped portions 73 and 73. As a result, the resin flow becomes turbulent, This is because fluid orientation, which causes orientation crystallization that causes whitening, is suppressed.
From the viewpoint of suppressing flow orientation, the length h of the stepped portion 73 (corresponding to the height difference between the horizontal bridging portion 75 and the first and second base portions 70 and 71) is the thickness of the strap band 25. It is good to be about. This is because if the stepped portion 73 is small, it is considered that the effect of suppressing flow orientation is lowered.

  In the state of FIG. 13 in which the upper lid 3 is inverted, the stepped portions 73 and 73 described above are directed downward, and the horizontal bridging portion 75 is formed at a position lower than the first and second base portions 70 and 71. Even in this case, whitening can be suppressed by the principle described above. However, in this case, since the opening function of the upper lid 3 may be lowered due to the pulling of the strap band 25, it is preferable that the stepped portion 73 is directed upward as described above.

Also in the hinge cap of the above-described aspect, a thickness distribution is formed at the joint portion between the strap band 25 and the cylindrical side wall 7 as in the hinge cap shown in FIGS. It gradually becomes thinner toward the 23 side. Therefore, as shown in the rear view of FIG. 12 and the partially enlarged view of FIG. 14, the joining line 51 between the lower surface of the strap band 25 and the cylindrical side wall 7 is an inclined surface inclined toward the hinge band 23 side. It has become. The combined use of such a configuration and the above-described stepped portion 73 can further improve the whitening prevention effect in the strap band 25.
Further, as shown in FIGS. 11 and 12, also in the hinge cap of this embodiment, the reverse V-shaped groove 60 and the horizontal surface 63 described above are formed on the lower surface of the hinge band 23. A joining line 23 a between the lower surface of the cylindrical wall 7 and the outer surface of the cylindrical side wall 7 is set so as to be positioned on a surface perpendicular to the cap axis L. Thereby, whitening at the hinge band 23 is also effectively prevented.

  As described above, in the hinge cap of the present invention, even when the upper lid 3 is repeatedly opened and closed, whitening of the strap band 25 and the hinge band 23 is effectively prevented. Will not be damaged. Further, since whitening is prevented, even when the upper lid 3 is frequently opened and closed repeatedly, the strap band 25 and the hinge band 23 do not peel or break.

As shown in FIGS. 1 to 14, the present invention has a double wall structure in which the cylindrical side wall 7 of the cap body 1 is divided into an inner side wall 7a and an outer side wall 7b. It is most preferably applied to a hinge cap.
That is, in the hinge cap in which the cylindrical side wall 7 has a double structure as described above, whitening particularly easily occurs in the hinge band 23 and the strap band 25. Probably, when the cap is molded, the molten resin passes through a narrow mold space corresponding to the outer wall 7b and then flows into a narrower mold space corresponding to the hinge band 23 and the strap band 25 to perform the molding. It is considered that the resin is easily flow-oriented in the hinge band 23 and the strap band 25, and orientation crystallization occurs through the flow-oriented, and thus whitening is likely to occur. In the present invention, by applying to such a hinge cap, this whitening can be effectively prevented, and the excellent waste disposal of such a double-walled hinge cap can be achieved. .

<Example 1>
The cap having the shape shown in FIGS. 1 to 4 was molded by injection molding using polyethylene. That is, in this cap, the thickness of the strap band 25 and the joint portion with the cylindrical side wall 7 is thick at the end away from the hinge band 23 and gradually becomes thinner toward the hinge band 23 side (specifically, The radius of curvature of the curvature surface at the end on the side away from the hinge band 23 is R1, and the radius of curvature of the end on the side of the hinge band 23 is R0.2). Is formed with an inverted V-shaped groove 60 and the surface between the groove 60 and the skirt portion 33 of the upper lid 3 is a horizontal plane.
A large number of such caps were formed, and whitening of the strap band 25 and the hinge band 23 was observed with the upper lid closed, but no whitening was observed for all caps.
In addition, the above cap was repeatedly opened and closed, but no whitening was observed.

<Example 2>
A cap having the same shape as that of Example 1 was formed except that the strap band 25 had two steps 73 as shown in FIGS.
Regarding this cap, as in Example 1, whitening of the strap band 25 and the hinge band 23 was observed with the upper lid closed, but no whitening was observed for all the caps.
In addition, the above cap was repeatedly opened and closed, but no whitening was observed.

<Comparative Example 1>
The thickness of the strap band is set so that the thickness of the strap band and the joint portion with the cylindrical side wall 7 is uniform from the end portion away from the hinge band 23 toward the hinge band 23 side (specifically, what is the hinge band 23? The radius of curvature of the curvature surface at the end on the far side and the curvature radius of the end on the hinge band 23 side are both R1), and no inverted V-shaped groove is formed on the lower surface of the hinge band 23 A cap was molded in the same manner as in Example 1 except that.
Regarding the cap, as in Example 1, whitening of the strap band 25 and the hinge band 23 was observed with the upper lid closed, and most of the strap band 25 and the hinge band 23 were whitened. It was. In particular, in the strap band 25, whitening occurred along the joint portion with the cylindrical side wall 7.

1: Cap body 3: Upper lid 5: Top plate portion 7: Cylindrical side wall 7a: Inner side wall 7b: Outer wall 23: Hinge band 25: Strap band 33: Upper lid skirt portion 60: Inverted V-shaped groove 73: Stepped portion

Claims (6)

A cap body fitted and fixed to the container mouth, and having a cylindrical side wall; and an upper lid connected to the cylindrical side wall of the cap body via a hinge band and two strap bands. A hinge connected to the upper end of the cylindrical side wall, and the strap band is connected to the outer surface of the cylindrical side wall at a position lower than the hinge band at both sides in the circumferential direction of the hinge band In the cap,
The thickness of the portion of the strap band joined to the outer surface of the cylindrical side wall gradually decreases from an end portion away from the hinge band side toward an end portion of the hinge band side. Hinge cap.   In a state where the upper lid is opened and inverted, a side cross section of the strap band is a first base portion extending horizontally from the outer surface of the cylindrical side wall to the upper lid side, and a cylindrical shape from the outer surface of the upper lid. A second base portion extending horizontally on the side wall, and the first base portion and the second base portion are connected to the horizontal bridging portion via an upward or downward stepped portion, respectively. The hinge cap according to claim 1, which has a shape. A cap body fitted and fixed to the container mouth portion and provided with a cylindrical side wall; and an upper lid connected to the cylindrical side wall of the cap body via a hinge band and two strap bands. A hinge cap connected to the upper end of the cylindrical side wall, and the strap band is connected to the outer surface of the cylindrical side wall at a position lower than the hinge band at both sides in the circumferential direction of the hinge band In
In a state where the upper lid is opened and inverted, a side cross section of the strap band is a first base portion extending horizontally from the outer surface of the cylindrical side wall to the upper lid side, and a cylindrical shape from the outer surface of the upper lid. A second base portion extending horizontally on the side wall, and the first base portion and the second base portion are connected to the horizontal bridging portion via an upward or downward stepped portion, respectively. A hinge cap characterized by having a shape.   In the state where the upper lid is opened and inverted, a groove having an inverted V shape is formed on the lower surface of the hinge band when viewed from a side cross section, and the groove crosses the hinge band. The hinge cap according to any one of claims 1 to 3, wherein a surface extending in the width direction of the band and extending from the groove toward the upper lid side is a horizontal plane perpendicular to the cap axis.   The hinge cap according to claim 4, wherein a joining line between the lower surface of the hinge band and the outer surface of the cylindrical side wall is located on a horizontal plane perpendicular to the cap axis.   The cylindrical side wall of the cap body has a double wall region that is divided into an inner wall and an outer wall by a slit whose thickness portion extends downward from the upper end, and the double wall region The hinge cap according to any one of claims 1 to 5, wherein the hinge band and the strap band are connected to an outer side wall.

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