JPS5944268B2 - container lid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a container lid, and more particularly to a container lid suitable for, but not limited to, synthetic resin containers for carbonated beverages such as beer.

Recently, relatively large capacity (2
1! , or 3i), containers made of polyethylene terephthalate (PET) have come into practical use.

Such a container generally has a neck portion having a female thread formed on the outer peripheral surface and a locking flange located below the female thread. As a container lid for sealing the mouth and neck of such a container, a metal shell comprising a top wall and a cylindrical skirt wall hanging from the periphery of the top wall, and a metal shell having an inner surface of the top wall. Container lids of the type constructed from a synthetic resin, such as polyethylene, liner are commonly used. A weakened line extending in the circumferential direction is formed on the skirt wall of the metal shell, and the skirt wall has a main part located above the weakened line and a pilfer-proof hem located below the weakened line. It is divided into. Synthetic resin liners generally include a sealing annular protrusion that is brought into close contact with the outer periphery of the mouth and neck of the container, and a positioning broken protrusion that is concentrically arranged inside the sealing annular protrusion. have When attaching such a container lid to the mouth and neck of the container to seal the mouth and neck, the container lid is fitted onto the mouth and neck, and pressing force is applied mainly to the boundary area between the top wall and the skirt wall of the metal shell. Then, the sealing annular protrusion of the synthetic resin liner is brought into close contact with the outer periphery of the edge of the mouth and neck, and while maintaining this state, the skirt wall is inserted along the male thread formed on the outer circumference of the mouth and neck. In addition to forming a female thread in the main part of the
The lower end of the pilfer-proof hem is deformed inward to be locked to the lower surface of a locking flange formed on the outer peripheral surface of the mouth and neck. When the container lid is removed from the mouth and neck of the container to open the mouth and neck, the container lid is rotated in the opening direction (generally counterclockwise when viewed from above). However, in the conventional container lids of the type described above, the so-called necessary opening torque required to rotate the container lid in the opening direction when opening the neck part is quite large, and it is often difficult to open the container lid. There are drawbacks that need to be resolved.

As a result of the inventors' investigation into such drawbacks,
The following facts were discovered.

When the content to be filled in the container is a carbonated beverage, such as beer, as is well known to those skilled in the art, after filling the container with beer and before attaching the container lid to the mouth and neck, the beer in the container should be removed. A so-called foaming step is carried out in which the foam is made to flow out from the mouth and neck, thus expelling the air present in the container. In such a case, when the container lid is attached to the mouth and neck, the beer that flows out from the mouth and neck remains between the mouth and neck and the container lid. The residual beer solidifies over time to produce a so-called beer cement effect, and this beer cement effect increases the required opening torque. In order to avoid the above-mentioned disadvantage that the necessary opening torque is quite large and opening is often difficult, G)! ] In order to reduce the pressing force applied to the container lid when attaching the container lid to the neck, and (b) to prevent the formation of the beer cement effect described above, the above-mentioned method is applied prior to attaching the container lid to the neck of the mouth. Possible methods include rinsing the mouth and neck with water after the foaming process. However, if the above-mentioned force formula (a) is adopted, there is a tendency that the sealing performance of the mouth and neck region deteriorates and becomes unacceptable. In addition, if the force formula (b) above is adopted, it is possible to obtain some results, but it is extremely difficult, if not impossible, to thoroughly wash the mouth and neck without causing washing water to flow into the container. Due to the difficulty, etc., fully satisfactory results cannot be obtained. The present invention has been made in view of the above facts, and its main purpose is to provide an improved container lid that can maintain sufficient sealing performance and reduce the required opening torque to a required value or less. .

As a result of intensive research and experiments, the present inventors have determined that the lower surface of the sealing annular protrusion, which is brought into close contact with the outer periphery of the edge of the mouth and neck in conventional container lids, is at an angle of 30 degrees or less with respect to the central axis. However, what is important is that the lower surface of the sealing annular protrusion forms an angle of 80 to 65 degrees, particularly 77 to 70 degrees, with respect to the central axis. It has been found that the above object can be achieved by tilting it downward. That is, according to the present invention,
A container lid for a container having a neck portion with a male thread formed on the outer peripheral surface, comprising a top wall and a cylindrical skirt wall hanging from the periphery of the top wall, the inner surface of the top wall In a container lid of the type in which a synthetic resin sealing protrusion is formed which is brought into close contact with the outer periphery of the mouth and neck; the lower surface of the sealing annular protrusion is 80° to 6
A container lid is provided which is characterized in that it is inclined outwardly and downwardly at an angle of 5 degrees, in particular 77 to 70 degrees.

A more detailed description will be given below with reference to the accompanying drawings.

Referring to FIG. 1, which illustrates one embodiment of a container lid constructed in accordance with the present invention, the illustrated container lid, generally designated by the numeral 2, comprises a metal shell 4 and a synthetic resin liner. It consists of 6. The metal shell 4, which is formed from a suitable sheet metal such as aluminum-based alloy, tinplate, or chromed steel, has a circular top wall 8 and a cylindrical skirt wall 10 depending from the periphery of the circular top wall 8. The skirt wall 10 is formed with a weakened line 12 extending in the circumferential direction, and the skirt wall 10 has a main portion 14 located on the upper edge of the weakened line 12 and a pilfer-proof hem located below the weakened line 12. It is divided into a section 16. The illustrated weakened line 12 is defined by a plurality of slits (cut grooves) 18 formed at intervals in the circumferential force direction and a so-called bridging portion 20 existing between the slits 18. 20 connects the pilfer-proof hem 16 to the main portion 14. Knurling or uneven shapes 22 and 24 are formed at the upper and lower ends of the main portion 14 to prevent slippage when the container lid 2 is rotated with a finger. A plurality of weakened lines 28 extending in the direction of the central axis 26 of the container lid 2 are formed on the pilfer-proof hem 16 at intervals in the circumferential direction. The illustrated weakening line 28 consists of a so-called score formed by reducing the thickness of the material. The illustrated liner 6 is molded from a suitable synthetic resin material such as polyethylene, polypropylene or polyvinyl chloride.
It has a sealing annular protrusion 30 and a positioning broken protrusion 32 arranged concentrically inside the sealing annular protrusion 30. Such a liner 6 is a top wall 8 of the metal shell 4.
It can be molded at a predetermined position on the inner surface of the mold by an embossing method well known to those skilled in the art. The above-described configuration of the illustrated container lid 2 is already known and is merely an example of the container lid 2 to which the present invention is applied.

Referring to FIG. 2 together with FIG. 1, in the container lid 2 constructed according to the present invention, the above-mentioned sealing member is brought into close contact with the outer circumferential edge of the mouth and neck of the container, as will be described later. The lower surface 34 of the annular projection 30 extends outwardly and downwardly at an angle α of 80 to 65 degrees, preferably 77 to 70 degrees, with respect to the central axis 26 of the container lid 2. This is very important.

As will be understood from the Examples and Comparative Examples described below, if the angle α exceeds 80 degrees, the sealing performance of the mouth and neck when the container lid is attached to the mouth and neck will be excessively reduced; 6
When the angle is smaller than 5 degrees, the required opening torque required to rotate the container lid 2 when removing the container lid 2 from the neck and opening the mouth and neck increases excessively. On the other hand, the positioning protrusion 32 is not necessarily necessary, but as will be mentioned later, when the container lid 2 is attached to the mouth and neck of the container, it guides and positions the container lid 2 as required with respect to the mouth and neck of the container. It is convenient for the device to be provided for this purpose, and any suitable form may be used as long as it can perform the intended function. The container lid 2 as described above may be applied to a container having a neck portion generally indicated by the numeral 36 in FIGS. 4 and 5. Although it can be molded from other materials such as glass, it can also be molded from suitable synthetic resins such as polyethylene terephthalate (P
The illustrated neck 36 provided at the upper end of the container, which is known per se and can be molded from ET), is generally cylindrical in shape and has a male thread 38 on its outer circumferential surface.
A locking flange 40 located below this male thread 38;
Furthermore, a so-called conveying ring 42 located below the locking flange 40 is formed. When attaching the container lid 2 to such a mouth and neck part 36 to seal the mouth and neck part 36, the container lid 2 is fitted onto the mouth and neck part 36. In this case, as can be easily understood by referring to FIG.
The annular positioning protrusion 32 is located adjacent to the inner circumference of the edge of the neck part 36, and the container lid 2 is positioned at a desired position relative to the neck part 36, that is, the container lid 2 is substantially positioned relative to the neck part 36. Guide and position it to a concentric position. Next, as shown in FIG. 4, the container lid 2 is pressed by the pressing tool 46 against the neck 36 of the container, which is suspended by supporting the conveying ring 42 by the support member 44. do. A pusher 46, which is of a well-known form per se, is mounted on a central member 5 which is elastically biased against the lower blade by a relatively weak spring member 48.
0 and an outer member 52 that is resiliently biased downwardly by a relatively strong spring member (not shown). As can be easily understood by referring to FIG. 4, such a pressing tool 46 mainly presses the metal shell of the container lid 2 by a stepped portion 53 formed on the lower surface of the outer member 52. A pressing force is applied to the boundary area between the top wall 8 and the skirt wall 10 at 4. With this, Figures 3 and 4
As can be easily understood by comparing and referring to FIGS.
It is deformed by being brought into close contact with the outer periphery of the edge. While maintaining such a state, a female thread 56 is formed in the main portion 14 of the skirt wall 10 along the male thread 38 of the neck portion 36 by a thread forming roller 54, which is known per se. By means of folding rollers 57, which are known per se, the lower end of the pilfer-proof seat 16 is deformed inwardly so as to lock onto the lower surface of the locking flange 40 of the neck portion 36. Thus, as shown in FIGS. 5 and 6, the container lid 2 is attached to the neck part 36, and the neck part 36 is sealed. When the container lid 2 is attached to the neck part 36, as clearly shown in FIG. be done. The positioning annular protrusion 32 on the liner 6 may be brought into contact with the inner circumference of the edge of the neck part 36, but as clearly shown in FIG. It may be separated somewhat from the In order to detach the container lid 2 attached to the mouth and neck part 36 as described above and open the mouth and neck part 36, turn the container lid 2 in a counterclockwise direction when viewed from above in FIG. Let it rotate.

In this way, since the female thread 56 formed on the main portion 14 of the skirt wall 10 is moved along the male thread 38 on the neck portion 36, the container lid 2 tends to move upward as it rotates. However, since the lower end of the pilfer-proof hem 16 is locked to the lower surface of the locking flange 40 of the mouth and neck part 36, upward movement is prevented. In this way, considerable stress is generated in the plurality of weakened lines 28 formed in the pilfer-proof hem 16, and the weakened lines 28 are broken, dividing the pilfer-proof hem 16 into a plurality of arc-shaped pieces. Each of the plurality of arcuate pieces is then displaced outward in the radial force direction around each of the bridge portions 20 in the weakened line 12, thereby causing the locking flange 40
is detached from the bottom surface of the Then, the entire container lid 2 moves upward as it rotates and separates from the neck part 36, thus opening the neck part 36. In the container lid 2 constructed according to the present invention, as described above, the lower surface 34 of the sealing annular protrusion 30 is at an angle of 8 with respect to the central axis 26 of the container lid 2.
It extends outwardly and downwardly at an angle α of 0 to 65 degrees, preferably 77 to 70 degrees.

Therefore, as will be understood from the Examples and Comparative Examples described later, when the container lid 2 is attached to the neck part 36, the mouth neck part 36 can be sufficiently sealed, and the contents filled in the container can be sealed. is beer, and after filling the container with beer and before attaching the container lid 2 to the neck and mouth portion 36, the beer in the container is foamed to flow out from the neck and neck portion 36,
Therefore, even if beer remains between the two after the container lid 2 is attached to the mouth and neck part 36 and the residual beer solidifies over time and a so-called beer cement effect is generated, the mouth and neck part 3
The required opening torque required to rotate the container lid 2 when removing the container lid 2 from the container 6 and opening the neck part 36 is made to a sufficiently low value. Example and Comparative Example Thickness: 0.
One side of the aluminum-based alloy plate of No. 25 was printed and coated with a vinyl-based protective lacquer, and the other side was coated with an epoxy paint containing sawn oxidized polyethylene.

The metal plate was then pressed so that the surface coated with the polyethylene oxide-containing epoxy paint was on the inside to form a metal shell as shown in FIG. 1 of C1. Next, high-pressure polyethylene (density = 0
．． 92, melt index -4.0) and was pressed to form a liner in the form as shown in FIGS. 1 and 2, thus forming Example 1 of the present invention.
Container lids Nos. 7 to 7 were produced. The dimensions of each part of the liner were as follows. In Examples 1 to 7, the inclination angle α of the lower surface of the sealing annular protrusion is as follows: For comparison, the inclination angle α of the lower surface of the sealing annular protrusion is as follows. , the above Examples 1 to 7
Comparative Examples 1 to 4, which were substantially the same container lids, were prepared.

However, in Comparative Examples 3 and 4, as shown in FIG. 7, the outer periphery of the lower surface of the sealing annular protrusion is made substantially flat so that the protrusion height H1 of the sealing annular protrusion is 1. It was confirmed that the results of the necessary opening torque test and the sealability test, which will be described later, are substantially the same as those without this.

) and Examples 1 to 7 of the present invention and Comparative Examples 1 to 4
Using the container lid, the following required opening torque test and sealing test were carried out.

(Required opening torque test) Edge outer diameter of mouth and neck D1 = 33, 6th edge inner diameter D2 = 30
．． 5? A 2-ton container made of polyethylene terephthalate (PET) was filled with commercially available draft beer.

Next, air was blown onto the draft beer in the container to foam the draft beer and cause a portion to flow out from the mouth and neck. Thereafter, for the containers of the first group, the container lids of Examples 1 to 7 and Comparative Examples 1 to 4 were attached to the openings of the containers in the same state as described with reference to FIG. It was attached to the neck.

At this time, the central member of the pressing tool was elastically pressed against the container lid with a force of 5 Kf, and the outer member of the pressing tool was elastically pressed against the container lid with a force of 180 Kf. For the second group of containers, cleaning water was sprayed on the outer circumferential surface of the mouth and neck to wash away the draft beer that flowed out from the mouth and neck and adhered to the outer circumference of the mouth and neck, and then the same method as described above was used in Example 1. The container lids of Comparative Examples 1 to 7 and Comparative Examples 1 to 4 were attached to the mouth and neck of the container.

Regarding containers in the first and second groups above, the following
The required opening torque was measured by the third force method. In the first force method, immediately after the container lid is attached to the mouth and neck of the container as described above, a torque in the direction of the opening force is applied to the container lid to separate the container from the mouth and neck of the container. The maximum required opening torque was measured using a commercially available torque meter.

The maximum value of the required opening torque was measured for 10 container lids of Examples 1 to 7 and Comparative Examples 1 to 4, and the average value thereof was determined, and the results shown in Table 1 below were obtained.
In the second method, after attaching the container lid to the mouth and neck of the container as described above, the container is left in a refrigerator at 5°C for one week, and then the maximum required opening torque is determined in the same manner as above. It was measured. Ten container lids of Examples 1 to 7 and Comparative Examples 1 to 4 were measured, and the average value was determined, and the results are shown in Table 2 below. In the third method, after attaching the container lid to the mouth and neck of the container as described above, the container is left in a constant temperature room at 40°C for one week, and then the maximum required opening torque is determined in the same manner as above. was measured.

Ten container lids of Examples 1 to 7 and Comparative Examples 1 to 4 were measured, and the average value was determined, and the results shown in Table 3 below were obtained. In view of the above measurement results, in the case of the container lids of Comparative Examples 1 and 2 and Examples 1 to 7, the required opening torque is within the required range, but for the container lids of Comparative Examples 3 and 4. It is understood that in some cases, the required opening torque tends to be excessive.

(Sealability Test) Commercially available draft beer was filled into the same container used in the above-mentioned required opening torque test.

Next, the container lids of Examples 1 to 7 and Comparative Examples 1 to 4 were attached to the mouth and neck of the container as described above. After that, the container was turned upside down and nitrogen gas was injected into the container through the syringe needle penetrated through the container lid to reduce the pressure inside the container to 11.
．． It increased to 2Kb4d.

Then, it was examined whether beer leaked from the mouth and neck of the container. When the above-described test was carried out on 10 container lids of Examples 1 to 7 and Comparative Examples 1 to 4, the number of lids from which beer leaked from the mouth and neck of the containers was as follows.
It was as shown in the table.

Judging from the results shown in Table 4, the container lids of Comparative Examples 3 and 4 and Examples 1 to 7 can sufficiently seal the mouth and neck of the container, but Comparative Examples 1 and 2 It is understood that in the case of a container lid, the sealing of the mouth and neck of the container becomes insufficient.

Although specific embodiments of the container lid constructed in accordance with the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications may be made without departing from the scope of the present invention. Needless to say, it is possible to make corrections.

For example, in the illustrated container lid, when the container lid attached to the mouth and neck of the container is removed from the mouth and neck, the plurality of weakened lines formed at the hem of the pilfer-proof are broken and the hem of the pilfer-proof is broken. It has a so-called pilfer-proof characteristic in which the section is divided into a plurality of arc-shaped pieces,
The present invention is applicable to other types of container lids having a pill-pull-proof property, for example, when a container lid attached to the mouth and neck of a container is removed from the mouth and neck. The weakened line of the book is broken and the pilfer-proof hem is made into a band-like shape, and the weakened line in the circumferential direction that is formed on the skirt wall and divides the skirt wall into the main part and the pilfer-proof hem is partially removed. When a container lid attached to the mouth and neck of a container is removed from the mouth and neck, a mold that is broken while leaving a part of the container, or a periphery formed on the skirt wall that divides the skirt wall into a main part and a pilfer-proof hem part. A type of container in which the line of weakening in the force direction is completely broken and the pilfer-proof hem is completely separated (therefore, the pilfer-proof hem is not separated from the mouth and neck but remains there), etc. It can also be applied to lids and can also be applied to container lids that do not have pilfer-proof properties.

Further, the illustrated container lid is of a so-called roll-on type in which female threads are formed on the skirt wall when the container lid is attached to the mouth and neck of the container. It can also be applied to container lids with threads formed thereon.

Furthermore, in the illustrated container lid, the shell having the top wall and the skirt wall is formed from metal, but if desired, the shell may also be formed from a suitable synthetic resin material.

In this case, the shell and liner can be formed from separate synthetic resin materials, or the shell and liner can be integrally formed from the same synthetic resin material.

[Brief explanation of the drawing]

FIG. 1 is a side view, partially in cross section, of a specific example of a container lid constructed in accordance with the present invention. 2 is a partial sectional view showing a part of the container lid of FIG. 1; FIG. FIG. 3 is a partial sectional view showing a state in which the container lid of FIG. 1 is fitted onto the mouth and neck of the container. FIG. 4 is a simplified cross-sectional view showing how the container lid of FIG. 1 is attached to the mouth and neck of the container as required.
FIG. 5 is a side view, partially in section, showing the container lid of FIG. 1 attached to the mouth and neck of the container as required. FIG. 6 is a partial cross-sectional view showing the container lid of FIG. 1 attached to the mouth and neck of the container as required. FIG. 7 is a partial sectional view showing the shape of the sealing annular protrusion in the container lids prepared as Comparative Examples 3 and 4. 2...Container lid, 4...
Metal shell, 6...Synthetic resin liner, 8
...Top wall, 10...Skirt wall, 3
0: Sealing annular protrusion, 32: Positioning annular protrusion, 34: Bottom surface of sealing annular protrusion, 36: Container opening neck.

Claims (1)

[Scope of Claims] 1. A container lid for a container having a neck portion with a male thread formed on the outer peripheral surface, comprising a top wall and a cylindrical skirt wall hanging from the periphery of the top wall. In a container lid of a type in which an annular sealing protrusion made of synthetic resin is formed on the inner surface of the flat wall and is brought into close contact with the outer periphery of the edge of the mouth and neck; the lower surface of the annular sealing protrusion is A container lid, characterized in that it is inclined outwardly and downwardly at an angle of 80 to 65 degrees with respect to the central axis. 2. Claim 1 in which the angle is 77 to 70 degrees
Container lid as described in section. 3. The container lid according to claim 1 or 2, wherein the inner surface of the top wall is formed with a positioning annular protrusion concentrically arranged inside the sealing annular protrusion. 4. The top wall and the skirt wall are made of metal, and a synthetic resin liner is provided on the inner surface of the top wall, and the sealing annular ridge and the positioning annular ridge are defined by the liner. A container lid according to claim 3. 5 A weakened line extending in the circumferential direction is formed on the skirt wall, and the skirt wall is divided into a main portion located above the weakened line and a pilfer-proof hem located below the weakened line. A locking flange located below the male thread is formed on the outer peripheral surface of the mouth and neck, and when the container lid is attached to the mouth and neck, the container lid is attached to the mouth and neck. Pressure is applied to the container lid to be fitted to bring the sealing annular protrusion into close contact with the outer periphery of the edge of the mouth and neck, and while maintaining this state, the main part of the skirt wall is moved along the male thread. 5. The container lid according to claim 4, wherein a female thread is formed on the skirt wall, and the lower end of the pilfer-proof hem of the skirt wall is deformed inward to be locked to the lower surface of the locking flange. 6. When a container lid is fitted to the mouth and neck and a pressing force is applied to the container lid, the pressing force is mainly applied to the boundary area between the top wall and the skirt wall to deform the boundary area. Container lid as described in section. 7. The container lid according to claims 1 to 6, wherein the container is made of synthetic resin. 8. The container lid according to claim 7, wherein the container is made of polyethylene terephthalate. 9. The container lid according to claim 8, wherein the container is filled with a carbonated beverage, and the carbonated beverage is foamed and flows out from the mouth and neck before attaching the container lid to the mouth and neck.