JPH08113258A - Synthetic resin cap - Google Patents

Abstract

PURPOSE: To obtain a synthetic resin cap which can maintain the tight sealing property of a container even under a high-temperature and high-pressure conditions. CONSTITUTION: A ring protrusion 32 is provided on a liner 24 of a synthetic resin cap 20 and inserted in a mouth 15 of a container when the cap 20 is mounted on the mouth 15 of the container. Thrust length A, i.e., the difference between the outside radius of the ring protrusion 32 and the inside radius of the mouth 15 of the container, is set to 0.2-0.6mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention improves a liner that presses against the upper end of the container mouth when it is attached to the container mouth, and improves the hermeticity of the container, especially under conditions where internal pressure is applied at high temperature. The present invention relates to a synthetic resin cap that can be used.

[0002]

2. Description of the Related Art FIGS. 3 and 4 exemplify a conventional synthetic resin cap. This cap 1 comprises a disc-shaped top plate portion 2 and a cylindrical portion 3 which hangs from the peripheral edge thereof. It is composed of a cap body 4 and a thin liner 5 provided on the inner surface of the top plate portion 2 of the cap body 4.
This tubular portion 3 has a horizontal score 7 with a plurality of bridges 6 left behind.
It is divided into a main portion 8 and a tamper evidence ring portion 9 (hereinafter referred to as a TE ring portion) below the main portion 8. On the inner wall surface of the main portion 8, the male screw 1 of the container mouth portion 15
A threaded portion 10 that is screwed into 6 is formed. In addition, on the inner wall surface of the TE ring portion 9, a plurality of plate-shaped tabs 11 protruding inward in the radial direction are arranged in a row along the circumferential direction.
An annular bead portion 12 is provided below the tabs 11. A seal ring 13 protruding inward in the radial direction is provided on the inner wall of the upper end of the tubular portion 3, and the peripheral edge of the liner 5 is supported by the seal ring 13.

The cap 1 is mounted by covering the container mouth portion 15 having a male screw 16 formed on the outer periphery of the mouth portion, turning the cap in the closing direction, and screwing and fitting. When the cap 1 is completely wound up, as shown in FIG. 4, the upper end of the container mouth portion 15 is pressed against the slightly thickened peripheral portion of the liner 5 provided on the inner surface of the cap 1 ( Top seal),
Further, the liner 5 around the seal ring 13 of the cap 1 also comes into contact with the outer periphery of the upper end of the container mouth portion 15 (outer side seal), and the container is sealed by the top seal and the outer side seal.

[0004]

However, after sealing the content liquid filling container using the conventional cap 1,
When it is placed under conditions of 60 degrees or more for sterilization treatment, the internal pressure of the container becomes high and the top plate portion 2 of the cap 1 bulges upward (called doming), resulting in the container mouth. The pressure of the upper end of the portion 15 against the peripheral edge of the liner 5 is weakened, the top seal is weakened, and the container mouth is subjected to thermal deformation and collapsed to the inward side, and the outer side seal is weakened. There was a problem that it might be damaged. Further, since the followability of the outer side seal of the liner 5 is impaired with respect to the contraction of the bottle mouth portion during cooling, there is a problem that the outer side seal may be weakened and the airtightness inside the container may be impaired. there were.

The present invention has been made in view of the above circumstances, and a container equipped with a cap is heated for sterilization and the like, and the container is heated even under high temperature and high internal pressure conditions such that the internal pressure is increased. An object of the present invention is to provide a synthetic resin cap capable of reliably maintaining the airtightness.

[0006]

A synthetic resin cap according to the present invention comprises a cap body composed of a top plate portion and a cylindrical portion hanging down from the peripheral edge thereof, and a liner provided on the inner surface of the top plate portion of the cap body. In a synthetic resin cap equipped with
The liner is provided with an annular protrusion that is inserted into the container mouth when the cap is attached to the container mouth, and the bite length which is the difference between the outer diameter radius of the annular protrusion and the inner radius of the container mouth is set. , 0.2 to 0.6 mm.

In the synthetic resin cap of the present invention, the protrusion height of the annular projection may be 0.5 to 2.0 mm.

In the synthetic resin cap of the present invention, the width of the annular projection may be 0.5 to 2.0 mm.

Further, in the synthetic resin cap of the present invention, the annular projection may be enlarged in diameter downward so that the angle formed between the outer peripheral surface of the annular projection and the vertical surface is 2 to 10 degrees.

Further, in the synthetic resin cap of the present invention, one or a plurality of ring-shaped projections that bulge outward in the radial direction may be provided on the outer peripheral surface of the annular projection.

[0011]

[Function] The synthetic resin cap of the present invention is applied to the liner,
An annular protrusion that is inserted into the container mouth when the cap is attached to the container mouth is provided, and the bite length, which is the difference between the outer diameter radius of the annular protrusion and the inner radius of the container mouth, is set to 0. 2 to
With the configuration set to 0.6 mm, when the cap is attached to the container mouth, the liner comes into contact with the upper end surface of the container mouth and the outer surface of the upper end to provide a top seal and an outer side seal. At the same time, the annular protrusion is fitted into the container mouth, and the outer peripheral surface of the annular protrusion comes into contact with the inner surface of the upper end of the container mouth to seal the inside side, thereby improving the hermeticity of the container.

Moreover, since the inner side seal of the container mouth portion by the annular projection maintains the sealed state even when the top plate portion of the cap bulges upward due to the doming phenomenon, the container with the cap attached is It is possible to reliably maintain the hermeticity of the container even under high temperature and high internal pressure conditions where the internal pressure is increased by heating for sterilization and the like. In addition, even if the container mouth is inwardly collapsed due to thermal deformation, the inner side seal of the liner ensures that the sealed state is maintained, and the inside of the liner is protected against contraction of the bottle mouth during cooling. The side seal reliably maintains the sealed state, and the container can be reliably maintained in hermeticity. By setting the bite length, which is the difference between the outer diameter radius of the annular projection and the inner radius of the container mouth, to 0.2 to 0.6 mm,
The effect of maintaining the hermeticity of the container under the conditions of high temperature and high internal pressure can be reliably obtained, and the increase in the opening torque when opening the cap is within the allowable range.

[0013]

1 and 2 show one embodiment of the synthetic resin cap of the present invention. In this embodiment, the cap 20 is made of a synthetic resin and includes a disc-shaped top plate portion 21 and a cylindrical portion 22 that hangs down from the periphery of the top portion 21.
And a thin-walled synthetic resin liner 24 provided on the inner surface of the top plate portion 21 of the cap body 23.

The tubular portion 22 has a main portion 27 and a TE below the main portion 27 by a horizontal score 26, leaving a plurality of bridges 25.
It is partitioned into a ring portion 28. On the inner wall surface of the main portion 27, the screw portion 2 that is screwed into the male screw 16 of the container mouth portion 15 is formed.
9 is formed. Further, on the inner wall surface of the TE ring portion 28, a plurality of plate-shaped tabs 30 protruding inward in the radial direction are provided.
Are lined up along the circumferential direction. Also, these tabs 3
An annular bead portion 31 is provided in the lower portion of 0. A seal ring 13 protruding inward in the radial direction is provided on the inner wall of the upper end of the cylindrical portion 22, and the peripheral edge of the liner 24 is supported by the seal ring 13.

The liner 24 is provided with an annular projection 32 bulging downward along the periphery of the liner 24 inward in the radial direction. The annular protrusion 32 is fitted into the mouth of the container mouth 15 when the cap 20 is attached to the container mouth 15, and the outer surface of the annular protrusion 32 can contact the inside of the upper end of the container mouth 15. .

The bite length (A dimension in FIG. 2) of the annular projection 32, which is the difference between the outer diameter radius of the annular projection 32 and the inner radius of the container mouth portion 15, is 0.2 to 0.6 mm. And the range. If the bite length A is less than 0.2 mm, the inner side seal of the container mouth portion 15 due to the annular protrusion 32 becomes weak, and the effect of maintaining the sealing property under the high temperature and high internal pressure conditions that causes doming is obtained. You will not get enough. When the bite length A is larger than 0.6 mm, the annular projection 32 and the container mouth 15 are strongly fitted to each other and the cap opening torque of the cap 20 becomes high, which exceeds the appropriate range of the cap opening torque. When the bite length A becomes large, capping becomes difficult.

The protruding height of the annular projection 32 (dimension B in FIG. 2) is 0.5 to 2.0 mm. If the protruding height B is smaller than 0.5 mm, the inner side seal of the container mouth portion 15 due to the annular protrusion 32 becomes weak, and the effect of maintaining the sealing property under the high temperature and high internal pressure conditions that causes doming is obtained. You will not get enough. This protruding height B
Is larger than 2.0 mm, the annular protrusion 32 and the container mouth portion 1
There is a possibility that the cap 20 and the cap 20 are strongly fitted to each other and the cap opening torque of the cap 20 becomes high, which exceeds the appropriate range of the cap opening torque.

The width of the annular protrusion 32 (C in FIG. 2)
The dimension) is 0.5 to 2.0 mm. This width B is 0.
If it is smaller than 5 mm, the strength of the annular projection 32 becomes weak and the annular projection 32 is likely to fall inward in the radial direction.
The effect of maintaining hermeticity under conditions of high temperature and high internal pressure cannot be sufficiently obtained. Further, if the width C is larger than 2.0 mm, the amount of resin in the liner 24 is large, which is uneconomical.

Explaining how to use the cap 20, the cap 20 has a male screw 16 formed on the outer periphery of the mouth, and a container mouth 15 having a bulging step 17 formed immediately below the male screw 16. The cover is put on, turned in the closing direction, and screwed and fitted. At this time, it is desirable that the flange 18 provided on the neck of the container is supported to bring it into a suspended state to prevent the container from rotating and to tighten the cap 20.
FIG. 1 shows a state in which the cap 20 is attached to the container mouth portion 15. As shown in this figure, in the attached state, the tab 30 on the inner peripheral surface of the TE ring portion 28 has a bulging step at its tip. It is in a state of standing upright toward the lower end of the portion 17 or almost horizontally.

When the cap 20 is attached to the container mouth portion 15, the liner 24 abuts the upper end surface and the outer surface of the upper end portion of the container mouth portion 15 to provide the top seal and the outer side seal, and the liner. The ring-shaped protrusion 32 provided on the ring 24 is fitted into the mouth of the container mouth portion 15,
The outer peripheral surface 32a of the container comes in contact with the inner surface of the upper end of the container mouth portion 15 (inner surface of the mouth) to perform inner side sealing, thereby improving the hermeticity of the container.

When the container equipped with the cap 20 is heated under conditions of high temperature and high internal pressure so as to increase the internal pressure of the container by heating the container for sterilization of the contents, the top plate of the cap is Although dome bulging upward occurs, in this cap 20, since the inner surface of the mouth of the container mouth portion 15 is side-sealed by the annular projection 32, a doming phenomenon occurs and the top plate portion of the cap bulges upward. Even in the case of the above, the hermetic sealing property of the inner side seal is reliably maintained. In addition, even if the container mouth is inwardly collapsed due to thermal deformation, the inner side seal of the liner ensures that the sealed state is maintained, and the inside of the liner is protected against contraction of the bottle mouth during cooling. The side seal reliably maintains the sealed state, and the container can be reliably maintained in hermeticity.

When the cap 20 attached to the container opening 15 is rotated in the opening direction, a plurality of tabs 30 provided on the inner surface of the TE ring portion 28 abut on the lower end of the bulging step 17 of the container opening 15. , The tab 30 is the lower end of the bulging step portion 17 and the bead portion 31.
The TE ring portion 28 is prevented from moving upward by being sandwiched between the TE ring portion 28 and the TE ring portion 28, and as a result, the plurality of bridges 25 connecting the TE ring portion 28 and the main portion 27 are cut off, and the TE ring portion 28 is cut. 28 is separated from the main part 27, and the opening is displayed.

The cap 20 has a structure in which the liner 24 is provided with an annular protrusion 32 which is inserted into the container mouth when the cap 20 is attached to the container mouth 15. When mounted on the container 15, the liner 24 abuts the upper end surface and the outer surface of the upper end portion of the container mouth portion 15 to perform a top seal and an outer side seal, and the annular protrusion 32 is fitted into the container mouth portion 15 to form an annular shape. The outer peripheral surface 32a of the protrusion 32 comes into contact with the inner surface of the mouth of the container mouth portion 15 to perform inner side sealing, so that the hermeticity of the container is enhanced. Moreover, the inner side seal of the container mouth portion 15 due to the annular projection 32 maintains the sealed state even when the top plate portion of the cap bulges upward due to the doming phenomenon, and therefore the container with the cap attached is sterilized. It is possible to reliably maintain the sealing property of the container even under the conditions of high temperature and high internal pressure such that the internal pressure is increased by heating for the above reasons.

The above embodiment is merely an example of the present invention, and it goes without saying that various modifications can be made. For example, in the above embodiment, the outer peripheral surface 3 of the annular protrusion 32 is
Although 2a is a vertical surface, as shown by the one-dot broken line in FIG. 2, an annular projection 33 whose diameter is expanded downward is provided, and the angle α formed by the outer peripheral surface of the annular projection 33 and the vertical surface is 2
The configuration may be set to 10 to 10 degrees. By providing the annular projection 33 whose diameter is expanded downward as described above, it is possible to further improve the effect of reliably maintaining the hermeticity of the container even under high temperature and high internal pressure conditions. This angle α is 2
When the angle α is larger than 10 degrees, the effect of strengthening the fitting of the annular projection 32 to the container mouth 15 is insufficient, and when the angle α is larger than 10 degrees, the fitting of the annular projection 32 to the container mouth 15 is strong. It becomes too high and the opening torque becomes high.

Further, in the above embodiment, the outer peripheral surface 32a of the annular projection 32 is a smooth surface, but one or a plurality of ring-shaped convex portions that bulge outward in the radial direction are formed on the outer peripheral surface of the annular projection 32. May be provided. In this way, the annular protrusion 32
By providing the ring-shaped convex portion on the outer peripheral surface 32a of the above, the fitting of the annular projection 32 into the container mouth portion 15 can be strengthened. Hereinafter, the effects of the present invention will be clarified by experimental examples.

(Experimental Example) A cap made of polypropylene having the same structure as that shown in FIG. 1 was used, and a liner having annular projections of various sizes was formed on the inner surface of the top plate (cap). Examples 1 to 5) were produced, the sealing property under high temperature and high internal pressure conditions was examined, and compared with a conventional type cap (comparative example) having no annular projection. Caliber 2
An 8 mm 1.5-liter PET bottle was filled with the content liquid (gas water), the caps of Experimental Examples 1 to 5 and the comparative example were attached to the mouth of the bottle, and each bottle with the cap attached was kept at 65 ° C. Put it in hot water and hold it for 30 minutes, then cool it to room temperature with water, and check the sealing property during heating and cooling (existence of gas leakage), seal performance evaluation of the cap attached to each bottle, opening torque I checked the value. The inner diameter of the bottle is 2
It was 0.6 mm (inner radius of 10.3 mm), and the gas pressure of each bottle was 2.18 kg / cm ² at 20 ° C. Table 1
The dimensions (A, B, C) of the bulging projections of the caps of Examples 1 to 5 and the comparative example used in the experiment are shown in Table 2, and Table 2 shows the sealing performance of each cap during heating and cooling. The presence or absence of gas (presence or absence of gas leakage), the evaluation of the sealing performance of the cap attached to each bottle, and the measurement results of the opening torque value at room temperature 24 hours after heating are shown.

[0027]

[Table 1]

[0028]

[Table 2]

As can be seen from the above results, the liner is provided with the annular protrusion, and the bite length A, which is the difference between the outer diameter radius of the annular protrusion and the inner radius of the container mouth, is 0.2 to 0.2.
The cap set to 6 mm was able to remarkably improve the sealing property under the conditions of high temperature and high internal pressure, as compared with the conventional type cap having no annular protrusion (comparative example).

[0030]

As described above, in the synthetic resin cap of the present invention, the liner is provided with the annular projection which is inserted into the container mouth when the cap is attached to the container mouth. When the cap is attached to the container mouth, the liner is brought into contact with the upper end surface of the container mouth and the outer surface of the upper end to form the top seal and the outer side seal, and the annular protrusion is fitted into the container mouth. The outer peripheral surface of the annular projection comes into contact with the inner surface of the mouth of the container to seal the inside of the container, thereby improving the hermeticity of the container. Moreover, the inner side seal of the container mouth part by the annular projection maintains the sealed state even when the top plate part of the cap bulges upward due to the doming phenomenon, so that the container equipped with the cap can be sterilized. Therefore, it is possible to reliably maintain the sealing property of the container even under high temperature and high internal pressure conditions such as heating and increasing the internal pressure. In addition, even if the container mouth is inwardly collapsed due to thermal deformation, the inner side seal of the liner ensures that the sealed state is maintained, and the inner side of the liner is protected against contraction of the bottle mouth during cooling. With the seal, the sealed state is reliably maintained, and the hermeticity of the container can be reliably maintained. Therefore, according to the present invention, the container equipped with the cap is heated for sterilization, etc., and the hermeticity of the container is reliably maintained even under high temperature and high internal pressure conditions such as when the internal pressure is increased. It is possible to provide a synthetic resin cap that can be manufactured.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a synthetic resin cap of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the same cap.

FIG. 3 is a front sectional view illustrating a conventional synthetic resin cap.

FIG. 4 is a cross-sectional view of essential parts showing a state in which the cap of FIG. 3 is attached to the container mouth.

[Explanation of symbols]

20 ... Cap, 21 ... Top plate part, 22 ... Cylinder part, 2
3 ... Cap body, 24 ... Liner, 25 ... Bridge, 26 ... Horizontal score, 27 ... Main part, 28 ... Tamper evidence ring part, 29 ... Screw part, 30 ...
Tabs, 31 ... Beads, 32, 33 ... Annular projections, 3
2a ... outer peripheral surface.

Claims (5)

[Claims] 1. A synthetic resin cap comprising a cap main body composed of a top plate part and a cylinder part hanging down from the peripheral edge thereof, and a liner provided on the inner surface of the top plate part of the cap main body, wherein the liner comprises: An annular protrusion that is inserted into the container mouth when the cap is attached to the container mouth is provided, and the bite length, which is the difference between the outer diameter radius of the annular protrusion and the inner radius of the container mouth, is set to 0. A synthetic resin cap characterized by being set to 2 to 0.6 mm. 2. The protrusion height of the annular protrusion is 0.5 to 2.0.
The synthetic resin cap according to claim 1, wherein the cap is made of mm. 3. The synthetic resin cap according to claim 1, wherein the annular projection has a width of 0.5 to 2.0 mm. 4. The diameter of the annular projection is expanded downward, and the angle formed by the outer peripheral surface of the annular projection and the vertical surface is from 2 degrees.
The synthetic resin cap according to any one of claims 1 to 3, wherein the cap is 10 degrees. 5. The synthetic resin according to claim 1, wherein one or more ring-shaped protrusions that bulge outward in the radial direction are provided on the outer peripheral surface of the annular protrusion. cap.