JP5085841B2 - Plastic cap - Google Patents

Description

  The present invention relates to a plastic cap, and more specifically, an inner ring that forms a seal in close contact with the inner peripheral surface of the container mouth wall on the inner surface of the cap top plate portion, and the upper end surface of the container mouth wall The present invention relates to a plastic cap in which a circumferential small protrusion that is in close contact with the outer ring and an outer ring that is in close contact with the outer peripheral surface of the container mouth wall.

Plastic caps include a screw type that is fitted by screw engagement with the container mouth wall and a type that is fitted into the container mouth by a stopper. In general, an inner ring and an outer ring are formed on the inner surface of the portion. That is, with the cap closed, the upper end portion of the container mouth wall enters between the inner ring and the outer ring, and the inner ring is in close contact with the inner surface of the container mouth wall so that a seal is formed. It has become. In this case, the outer ring is in close contact with the outer peripheral surface of the container mouth wall so that the close contact between the inner ring and the inner peripheral surface of the container mouth wall is stably maintained. Further, in the region between the inner ring and the outer ring, a small circumferential protrusion is formed to be in close contact with the upper end surface of the container mouth wall to supplement the sealing performance (for example, Patent Document 1). reference).
Japanese Patent Laid-Open No. 2002-173151 (FIG. 2)

  In the cap formed with the seal structure as described above, the minute space formed between the upper end portion of the container mouth wall and the inner surface of the cap is sealed by the inner ring and the outer ring. In addition, the container content liquid adhering to the upper end of the container mouth wall may be sealed in this minute space. In particular, recently, there is a tendency to fill the container content liquid up to the upper end of the container mouth wall or the vicinity thereof so that the head space of the container becomes small, and therefore the content liquid tends to be contained in the minute space. Is strong.

  When the cap is closed in a state where the liquid has entered the micro space as described above, particularly in the screw cap, the liquid that has entered the micro space acts as a lubricant, and when the cap is tightened, the outer ring and As a result of slipping between the container mouth wall and the cap, the cap is wound more than necessary, making it difficult to open the cap.

  In addition, the cap having the structure as in the above prior art has high sealing performance because the upper end portion of the container mouth wall is sandwiched between the inner ring and the outer ring. There is a problem of being bad. That is, when used as a cap for a carbonated beverage bottle or the like, if the bottle internal pressure increases due to a temperature rise or the like, degassing is not performed effectively, and thus inconvenience such as cap jumping from the bottle mouth is likely to occur. Such a problem may also occur when applied to bottles for juice drinks such as juice. That is, when the fruit juice drink undergoes secondary fermentation and carbon dioxide gas is generated (which often occurs when the juice drink is left in the bottle and the cap is resealed and left for a long period of time), the bottle pressure is still low. As a result, the cap may fly off from the bottle mouth.

  In order to solve the above problems, doming of the cap top plate portion that occurs when the inner pressure of the bottle rises by providing a notch (not in contact with the outer surface of the container mouth wall) in a part of the outer ring. It is conceivable that degassing is performed through the notch by (bulging outward). However, when such a notch is provided, the sealing performance may be impaired due to a decrease in the strength of the outer ring.

Accordingly, an object of the present invention is to form a plastic cap in which a container mouth wall is held between an inner ring and an outer ring formed on the inner surface of the top plate portion to form a seal structure, and is formed at the upper end portion of the container mouth wall. An object of the present invention is to provide a cap in which the container content liquid is sealed in the space to be opened, and the openability of the container content liquid is prevented from being lowered by the containment of the container content liquid.
Another object of the present invention is to prevent the above-described deterioration in the opening performance without impairing the sealing performance, and to make the cap tightening state unstable by reducing the cap tightening torque. An object of the present invention is to provide a cap that is prevented.
Still another object of the present invention is to provide a plastic cap that has improved gas venting without impairing excellent sealing performance and effectively prevented the cap from jumping due to an increase in internal pressure inside the container.

According to the present invention, comprising a top plate portion, and a skirt-like side wall lowered from the periphery of the top plate portion,
The inner surface of the skirt-shaped side wall is formed with a screw threadedly engaged with the outer surface of the container mouth wall. An inner ring that is in close contact with the inner peripheral surface of the container mouth wall to form a seal, and an outer ring that is in close contact with the outer peripheral surface of the container mouth wall at a position below the upper corner of the outer peripheral surface of the container mouth wall. In the plastic cap that is formed,
On the inner surface of the base portion of the outer ring, a first inclined surface or a convex portion that is in close contact with the outer peripheral corner portion of the upper end of the container mouth at the final stage of the cap tightening is formed,
Wherein the inner surface of the outer ring, the are formed second inclined surface extending downwardly from the lower side of the first inclined surface or a convex portion toward the cap center side, least also a second of said outer ring A notch is provided at the position of the inclined surface, and the second inclined surface is in close contact with the outer peripheral surface of the container mouth wall when attached to the container mouth, but does not contribute to the seal. A characteristic plastic cap is provided.

In the present invention,
1. On the inner surface of the top plate portion, a small circumferential protrusion is formed between the inner ring and the outer ring, which is in close contact with the upper end surface of the container mouth wall,
2. The notch is formed so as to leave at least the first inclined surface on the inner surface side of the outer ring, and is formed so as to be deeply cut above the inner surface side on the outer surface side of the outer ring;
Is preferred.

  In the present invention, a notch portion is formed in a part of the outer ring provided on the inner surface of the top plate portion. That is, since such a notch is formed, when the cap is attached to the container mouth wall, the space between the upper end of the container mouth wall and the inner surface of the cap top plate is interposed through the notch. Thus, communication with the outside of the outer ring is established. Accordingly, even when the container content liquid adheres to the upper end surface of the container mouth wall when the cap is closed, such container content liquid is not sealed in the space and is not passed through the notch. It flows down to the outside. Thus, according to the present invention, it is possible to effectively prevent a decrease in the openability due to the container content liquid being sealed in the minute space at the upper end of the container mouth wall.

  In addition, a notch is formed in a part of the outer ring, so that when the cap is attached to the container mouth, the cap can be smoothly inserted and the winding state can be effectively prevented from becoming unstable. can do. Furthermore, when the internal pressure of the container rises due to secondary fermentation of the liquid in the container and the top plate portion is domed, degassing is effectively performed through the notch, and cap skipping due to the increase of the internal pressure of the container is effectively prevented. .

  Further, an inclined portion or a convex portion that is in close contact with the outer peripheral corner portion at the upper end of the container mouth portion is formed on the inner surface of the base portion of the outer ring formed on the inner surface of the top plate portion. That is, since the inclined portion or convex portion of the inner surface of the outer ring base portion is in close contact with the container mouth wall, the inner ring and the outer ring (inclined portion of the inner surface of the base portion) regardless of the formation of the notch described above. Or a convex structure) is secured over the entire circumference of the cap, so that the deterioration of the sealing performance associated with the formation of the notch as described above can be effectively avoided. In addition, the bacteria can be effectively prevented from being sucked into the container.

  Also, even when a flaw or the like occurs near the upper end portion of the container mouth during the container molding process or when the container is supplied, the inner ring and the inclined part or convex part formed on the inner surface of the base part of the outer ring Good sealing performance can be ensured.

The present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a partially sectional side view showing a state in which the screw cap of the present invention is applied to a container
FIG. 2 is an enlarged side sectional view showing a main part of a container to which the screw cap of FIG. 1 is applied,
3 is a rear view of the screw cap of FIG.
FIG. 4 is an enlarged cross-sectional view showing a main part in another aspect of the screw cap of the present invention,
FIG. 5 is an enlarged cross-sectional view showing a main part in still another aspect of the screw cap of the present invention.

  Referring to FIG. 1, this screw cap is roughly composed of a top plate portion 1 and a skirt-like side wall 2 depending from the peripheral portion of the top plate portion 1. An opening history explicit band (TE band) 4 is provided via a breakable bridge 3.

  An inner ring 5 is formed on the inner surface of the top plate portion 1 so as to extend downward with a gap from the skirt-shaped side wall 2. An outer ring having a lower height than the inner ring is provided outside the inner ring 5. 7 is provided. Further, if necessary, a small circumferential protrusion 9 serving as an auxiliary seal is formed between the inner ring 5 and the outer ring 7.

  A thread 10 is formed on the inner surface of the skirt-shaped side wall 2, and this thread 10 engages with a thread 51 formed on the outer surface of the container mouth wall 50. That is, by rotating the skirt-like side wall 2 in the closing direction (that is, tightening) and screwing the screw 10 with the screw 51 on the outer surface of the container mouth wall 50, this cap 50.

  In a state where the cap is mounted on the container mouth wall 50, the outer surface of the inner ring 5 is the container mouth at a position lower than the inner peripheral surface of the container mouth wall 50, particularly the upper end corner of the container mouth wall 50. By closely contacting the inner peripheral surface of the part wall 50, the inside of the container is effectively sealed.

  In general, the inner surface of the outer ring 7 is in close contact with the outer peripheral surface of the container mouth wall 50, particularly at a position below the upper corner of the container mouth wall 50. When the side wall 2) is swung in the direction of opening, the inner ring 5 and the outer ring 7 are rotated concentrically so that the sealing by the inner ring 5 is stably maintained and the seal is broken. This is because the angle is wide. That is, the front end portion of the outer ring 7 does not directly form a seal, and may be shorter than the inner ring 5.

  Further, in the state where the cap is tightened, the circumferential small projection 9 abuts on the upper end surface 50a of the container mouth wall 50, and thereby the sealing position is fixed. In addition, when a force is accidentally applied from the outside with the cap being tightened, the outer ring 7 and the circumferential small protrusion 9 cause a close contact portion between the inner ring 5 and the container mouth wall 50 (seal The stress concentration on the part) is alleviated, and seal breakage and deformation of the inner ring 5 are effectively prevented.

  An anti-slip knurl 12 is formed on the outer surface of the skirt-like side wall 2 so that the cap can be smoothly turned in the closing direction and the opening direction.

  A known flap piece 14 is provided on the inner surface of the TE band 4 so that it can be engaged with the jaw 52 of the container mouth wall 50. That is, when the cap wound around the container mouth wall 50 is opened, the flap piece 14 comes into contact with the jaw 52 and the rise of the TE band 4 is restricted. On the other hand, the skirt-like side wall 2 is rotated and lifted in the opening direction. Therefore, before the seal portion (the close contact portion between the inner ring 5 and the container mouth wall 50) is released, the bridge 3 connecting the lower end of the skirt-like side wall 2 and the TE band 4 is broken, and the TE band 4 is a cap. Leave. Thus, since the TE band 4 is detached from the cap, it is possible to recognize the fact that the cap is once opened or the seal portion is broken.

  In the present invention, as shown in FIGS. 2 and 3, the first feature is that a notch 20 is formed in a part of the outer ring 7.

  That is, when the cap is wound around the container mouth portion, if the space between the upper end surface 50a of the container mouth wall 50 and the inner surface of the top plate portion 1 is completely sealed, the container mouth There is a possibility that the liquid in the container attached to the upper end surface 50a of the part wall 50 may be contained. In particular, when the content liquid is filled to a full or nearly full state in the container, the content liquid tends to adhere to the upper end surface 50a of the container mouth wall 50 due to the scattering of the content liquid. ing. Further, when the inner surface of the outer ring 7 is in close contact with a position below the upper end corner portion of the container mouth wall 50, the content liquid is particularly easily contained.

  As described above, if the adhering container liquid is sealed, it becomes difficult to open the cap. That is, the contained container liquid functions as a lubricant between the inner surface of the outer ring 7 and the outer surface of the container mouth wall 50 at the final stage of winding, and as a result, the cap is tightened more than necessary. In some cases, a doming phenomenon that the top plate portion 1 swells may occur.

  However, according to the present invention, the notch portion 20 is formed in the outer ring 7, and when the cap is tightened, the space between the upper end surface 50a of the container mouth wall 50 and the inner surface of the top plate portion 1 is not sealed, The outer ring 7 communicates with the outside. Therefore, when the cap is tightened, the content liquid adhering to the upper end surface 50 a of the container mouth wall 50 is discharged to the outside through the notch portion 20. Accordingly, it is possible to effectively prevent excessive tightening or doming phenomenon due to containment of the content liquid adhering to the upper end surface 50a, and to improve the plug-openability. Further, the formation of the notch 20 as described above also has an effect of improving the gas venting property. That is, when the inner pressure of the container rises due to secondary fermentation or the like of the liquid in the container and the top plate portion 1 undergoes doming deformation, gas is easily vented through the notch portion 20, and as a result, the inner pressure of the container increases. Cap jumping can be effectively prevented.

  In the present invention, when the cap is tightened, the container content liquid adhering to the upper end surface 50a of the container mouth wall 50 is smoothly discharged to the outside, or the degassing is effectively performed by increasing the container internal pressure. It is preferable to form a plurality of the notches 20 as described above, and it is preferable to form the notches 20 in a well-balanced manner over the entire circumferential direction. Incidentally, in the example of FIG. 3, three notches 20 are formed at equal intervals.

  The second feature of the present invention is that the inner surface of the base portion of the outer ring 7 is an inclined portion (first inclined surface) 7a that is in close contact with the outer peripheral corner portion of the upper end of the container mouth portion. That is, as is apparent from FIG. 2, the notch 20 is formed leaving the first inclined surface 7a, and the outer peripheral corner portion 50b at the upper end of the container mouth wall 50 has the 1 inclined surface 7a is in close contact. Therefore, even in the portion where the notch 20 is formed, the container mouth wall 50 is formed by the inner ring 5, the outer ring 7 (first inclined surface 7a), and the circumferential small protrusion 9 provided as necessary. Is stably secured, stress concentration on the close contact portion (seal portion) between the inner ring 5 and the container mouth wall 50 is alleviated, and deterioration of the sealing performance due to the formation of the notch portion 20 is effectively avoided. Is possible. Further, even when thickness unevenness or scratches occur on the container mouth wall 50, the outer peripheral surface of the inner ring 5 or the first inclined surface 7a is the inner peripheral surface of the container mouth wall 50 or the upper end thereof. Since it adheres over the entire periphery of the outer peripheral corner portion 50b, it is possible to ensure good sealing performance.

  In the present invention, the inclination angle θ of the first inclined surface 7a with respect to the vertical line is not particularly limited, but the first inclined surface 7a is in close contact with the outer peripheral corner portion 50b at the upper end of the container mouth wall 50 with a sufficient contact area. Therefore, it is usually preferable to be in the range of 30 to 60 degrees.

  Further, the outer ring 7 has a second inclined surface 7b that extends downward from the lower end of the first inclined surface 7a toward the cap center side. In the second inclined surface 7b, the container mouth wall It is preferable that the shape be in close contact with 50 (a portion below the outer corner portion 50b). That is, by having the shape having the second inclined surface 7b as described above, both the first inclined surface 7a and the second inclined surface 7b can be smoothly connected to the container mouth wall by tightening the cap. 50. In addition, from the lower part to the lower end of the second inclined surface 7b, the third inclined surface 7c extending toward the outer side of the cap can be formed in order to smoothly tighten the cap and reduce the closing torque. Is preferred.

Further, as is apparent from FIG. 2, the notch 20 is formed so as to leave at least the first inclined surface 7 a on the inner surface side of the outer ring 7, but on the outer surface side of the outer ring 7, the inner surface side thereof. It is preferable to have a shape that is deeply cut out upward. That is, the outer ring 7 is notched deeply upward, thereby providing flexibility to the outer ring 7, reducing the closing torque when the cap is tightened, and stabilizing the tightened state. However, if the outer surface side of the outer ring 7 is cut out too deeply, the strength of the cap is reduced, and the impact resistance may be reduced. Therefore, as shown in FIG. 2, the thickness t ₁ of the top plate portion 1 at the outer surface side root portion of the outer ring 7 is smaller than the minimum thickness t ₂ of the top plate portion 1 between the outer ring 7 and the inner ring 5. It is preferable to keep the thickness thick.

  Furthermore, although the example mentioned above is an example of a screw cap, it is also possible to apply to a stopper type in which the container mouth wall is fitted and fixed between the inner ring and the outer ring.

  Moreover, in this invention, a convex part can also be provided instead of the 1st inclined surface 7a (inclined part) mentioned above. The principal part of the cap of this aspect is shown in FIG.

  The cap of FIG. 4 is exactly the same as the cap shown in FIGS. 1 to 3 except that a convex portion 30 is provided instead of the first inclined surface 7a at the inner base of the outer ring 7. The convex portion 30 is formed so as to be in close contact with the entire outer periphery corner portion (shoulder portion) 50 b at the upper end of the container mouth portion 50. That is, by forming such a convex portion 30, the inner ring 5 and the outer ring 7 (in the portion where the notch portion 20 is formed are exactly the same as when the first inclined surface 7 is formed. The seal with the container mouth wall 50 by the convex portion 30) and the circumferential small protrusion 9 (auxiliary seal) provided if necessary is stably secured, and the deterioration of the sealing performance due to the formation of the notch portion 20 is effectively avoided. It becomes possible. In addition, even when the container mouth wall 50 is uneven in thickness, the formation of the convex portion 30 can ensure good sealing performance. In particular, such a convex portion 30 is tightly intruded to the outer peripheral corner portion 50b of the upper end of the container mouth portion 50 as compared with the first inclined surface 7a described above, thereby preventing deterioration in sealing performance. It is extremely excellent in effect.

  Moreover, in the example of FIG. 1 thru | or FIG. 4 mentioned above, although the notch part 20 becomes the shape which notched the whole thickness direction of the outer ring 7 under the 1st inclined surface 7a or the convex part 30, but. For example, as shown in FIG. 5, only the inner peripheral surface side of the outer ring 7 may be partially cut out. (In FIG. 5, the convex portion 30 is formed, but when the first inclined surface 7a is formed, the cutout portion 20 can of course be shaped as described above.)

The cap of the present invention described above is injected using various plastics such as low-, medium- or high-density polyethylene, linear low-density polyethylene, polypropylene, thermoplastic polyester, polyamide, styrenic resin, and S resin. It can be manufactured by integral molding such as molding and compression molding.

It is a partial cross section side view showing the state where the screw cap of the present invention was applied to the container. It is a sectional side view which expands and shows the principal part of the container to which the screw cap of FIG. 1 was applied. FIG. 3 is a bottom view of the screw cap of FIG. 2. It is sectional drawing which expands and shows the principal part in the other aspect of the screw cap of this invention. It is sectional drawing which expands and shows the principal part in the further another aspect of the screw cap of this invention.

Explanation of symbols

1: Top plate part 2: Skirt-like side wall 5: Inner ring 7: Outer ring 7a: First inclined surface 9: Small circumferential protrusion 20: Notch part 30: Convex part 50: Container mouth part wall

Claims (3)

A top plate portion, and a skirt-like side wall lowered from the periphery of the top plate portion,
The inner surface of the skirt-shaped side wall is formed with a screw threadedly engaged with the outer surface of the container mouth wall. An inner ring that is in close contact with the inner peripheral surface of the container mouth wall to form a seal, and an outer ring that is in close contact with the outer peripheral surface of the container mouth wall at a position below the upper corner of the outer peripheral surface of the container mouth wall. In the plastic cap that is formed,
On the inner surface of the base portion of the outer ring, a first inclined surface or a convex portion that is in close contact with the outer peripheral corner portion of the upper end of the container mouth at the final stage of the cap tightening is formed,
Wherein the inner surface of the outer ring, the are formed second inclined surface extending downwardly from the lower side of the first inclined surface or a convex portion toward the cap center side, least also a second of said outer ring A notch is provided at the position of the inclined surface, and the second inclined surface is in close contact with the outer peripheral surface of the container mouth wall when attached to the container mouth, but does not contribute to the seal. Characteristic plastic cap.   2. The plastic cap according to claim 1, wherein a small circumferential protrusion is formed on the inner surface of the top plate portion between the inner ring and the outer ring so as to be in close contact with the upper end surface of the container mouth portion wall.   The notch portion is formed so as to leave at least the first inclined surface on the inner surface side of the outer ring, and is formed so as to be deeper notched above the inner surface side on the outer surface side of the outer ring. The plastic cap according to 1 or 2.

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