JP2003175948A - Synthetic resin cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin cap with which high sealability can be kept even when an internal pressure of a container rises. <P>SOLUTION: An annular inner seal protrusion 12 to be fitted into a container mouth 20 and an annular opening end seal protrusion 13 to come into contact with an opening end 20b of the container mouth 20 are formed on an internal surface of a top plate 2 of a cap body 4 including the top plate 2 and a tube 3 hanging from a periphery thereof. The opening end seal protrusion 13 is structured to be bent in the direction of widening a diameter until it comes into contact with the cap body 4. A positioning projection 16 which comes into contact with the opening end 20b when the projection 13 has bent into contact with the cap body 4 is provided on the top plate 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin cap that is attached to a container mouth to close the container mouth.

[0002]

2. Description of the Related Art As a synthetic resin cap of this type,
There is a linerless type in which the liner is omitted and the cap body has a sealing function. As a linerless type cap, a cap having an inner seal protrusion fitted in the container mouth is widely used.

[0003]

In the conventional synthetic resin cap, when the cap is attached to the container mouth, the sealing performance is deteriorated if the tightening is insufficient, and the opening torque is excessive if the tightening is excessive. There was a problem that became. Therefore, there has been a demand for a technique capable of reliably optimizing the sealing property and the opening torque. The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a synthetic resin cap capable of reliably optimizing sealing performance and opening torque.

[0004]

In the cap made of synthetic resin of the present invention, an annular opening end sealing protrusion that abuts the opening end of the container mouth is formed on the inner surface of the top plate portion, and the opening end sealing protrusion is When this synthetic resin cap is attached to the container mouth, the container mouth causes it to bend and deform in the radial direction until it comes into contact with the cap body. It is characterized in that a positioning projection is provided which comes into contact with the opening end when it is bent and deformed until it comes into contact. The positioning protrusion is preferably provided integrally with the inner seal protrusion. The open end seal projection may be configured to include an upright tubular portion extending downward from the top plate portion, and an extended tubular portion extending from the upright tubular portion in a skirt shape.

[0005]

1 and 2 show an embodiment of a synthetic resin cap according to the present invention. A synthetic resin cap 1 shown here is a disc-shaped top plate portion 2 and its top. On the inner surface of the top plate portion 2 of the cap body 4 including the cylindrical portion 3 that hangs from the peripheral edge, an annular inner seal protrusion 12 fitted in the container mouth portion 20 and an opening end 20b of the container mouth portion 20 (especially outside thereof). An annular open end seal projection 1 that abuts the peripheral edge portion 20c).
3 and 3 are formed so as to project downward. Reference numeral 21 in the figure denotes a container to which the cap 1 is attached. The container 21 is made of synthetic resin such as polyethylene terephthalate (PET), glass, or the like, and has a male screw portion 22 formed on the outer periphery of the container mouth 20 and a bulging step portion 23 formed below the male screw portion 22. . Opening end 20b of container mouth 20
Are formed flat along a substantially horizontal surface.

The cylindrical portion 3 of the cap body 4 has a horizontal score 6
Is divided into a main portion 8 above the horizontal score 6 and a tamper evidence ring portion (TE ring portion) 9 connected to a lower end of the main portion 8 by a bridge 7. On the inner wall surface of the main portion 8, a screw portion 10 that is screwed into the male screw portion 22 of the container mouth portion 20 is formed. On the inner wall surface of the TE ring portion 9, when the cap 1 is opened, the TE
A plurality of thin plate-shaped locking means tabs 11 are provided to prevent movement of the ring portion 9. The cap 1 is made of a synthetic resin material such as high density polyethylene or polypropylene.

The inner seal projection 12 is adapted to contact the inner peripheral surface 20a of the container mouth portion 20 when it is fitted into the container mouth portion 20. The inner seal projection 12 is preferably formed such that the diameter thereof gradually increases in the protruding direction (downward), and the outer diameter of the maximum outer diameter portion 12 a is larger than the inner diameter of the container mouth portion 20.

The inner seal projection 12 is preferably formed so as to be elastically deformable in the diameter reducing direction so that it can be fitted into the container opening 20. That is, as shown by the chain double-dashed line in FIG. 2, the inner seal projection 12 can be elastically bent and deformed in the radial direction (the direction in which the tip 12c moves radially inward) in the base portion 12b. It is preferable to configure.

The protruding length of the inner seal protrusion 12 is 1 to 5
mm (preferably 2 to 4 mm) is suitable.
The thickness of the inner seal protrusion 12 is preferably 0.5 to 2 mm (preferably 0.5 to 1 mm). The inclination angle of the outer surface of the inner seal projection 12 with respect to the vertical direction (direction perpendicular to the top plate portion 2) is 5 to 30 degrees (preferably 10 to 30 degrees).
20 degrees) is preferable. As for the height position of the maximum outer diameter portion 12a, the distance between the maximum outer diameter portion 12a and the top plate portion 2 is 4 mm.
It is preferable to set it so as to be below (preferably 3 mm or less). The outer diameter of the maximum outer diameter portion 12a is 21.74.
~ 23.74 mm (preferably 21.94-22.94)
mm) is preferable. The difference between the outer diameter of the maximum outer diameter portion 12a and the inner diameter of the container mouth portion 20 is preferably 1 mm or less (preferably 0.1 to 0.6 mm).

The opening end sealing projection 13 is for sealing the opening end 20b (particularly the outer peripheral edge portion 20c) of the container mouth portion 20 and is formed radially outward of the inner sealing projection 12 and has a top plate portion. It has a cylindrical upright tube portion 13a that extends substantially vertically downward from the inner surface of 2, and an extended tube portion 13b that extends obliquely downward from the lower end of the upright tube portion 13a in a skirt shape.

The projection length of the opening end seal projection 13 is from 1 to
It is preferably 4 mm (preferably 1.5 to 3 mm). The length of the upright tube portion 13a is preferably 0.5 to 3 mm (preferably 1 to 2 mm), and the thickness is 0.1.
It is suitable to be ˜1 mm (preferably 0.2 to 0.5 mm). The length of the expansion tube portion 13b is 0.5 to 3 mm
(Preferably 1 to 2 mm), and the thickness is preferably set to be larger than the thickness of the upright cylindrical portion 13a, specifically, 0.2 to 1.5 mm (preferably 0 mm). 4 to 1 mm) is preferable. The angle of inclination of the expansion tube portion 13b with respect to the vertical direction is preferably 20 to 60 degrees.

The opening end seal projection 13 is formed by the upright cylindrical portion 13a.
The base end portion 13c is formed so as to be bent and deformable in the radial direction. The inner diameter of the upright cylindrical portion 13a is set smaller than the outer diameter of the container mouth portion 20. The diameter of the lower edge portion 13d of the expansion tubular portion 13b is preferably set larger than the outer diameter of the container mouth portion 20.

A thin portion 2b, which is thinner than the outer peripheral portion 2a, is formed in the central portion of the top plate portion 2. The thin portion 2b is formed closer to the center than the base portion 12b of the inner seal protrusion 12. The thin portion 2b is preferably circular. Thin part 2b
Has a thickness of 0.5 to 2.0 mm (preferably 1.0 to
1.5 mm) is preferable. The height difference of the step portion 2c between the outer peripheral portion 2a and the thin portion 2b is 0.1 to 1.0 m.
It is suitable to be m (preferably 0.2 to 0.8 mm).

At the corner 15 on the inner surface side of the portion where the top plate 2 and the cylinder 3 are connected, a reinforcing wall 14 is formed which expands in a taper shape from the upper side to the lower side so as to fill this corner 15. Has been formed. The reinforcing wall portion 14 enhances the rigidity of the connecting portion of the top plate portion 2 and the tubular portion 3, and prevents the top plate portion 2 from bulging and deforming when the internal pressure of the container 21 rises. Is 0.2 to 2 mm (preferably 0.5 to 1.8 mm)
Is preferred. The reinforcing wall portion 14 is preferably made of the same material as the cap body 4 and is formed integrally with the cap body 4.

In the cap 1 of this embodiment, the top plate portion 2
The opening end 20 of the container mouth 20 to which the cap 1 is attached.
A positioning protrusion 16 that abuts b is provided. The positioning convex portion 16 is for making the distance between the top plate portion 2 and the opening end 20b substantially constant and for making the winding tightening angle at the time of mounting the cap substantially constant. The positioning convex portion 16 has a substantially rectangular cross section and is directed downward. It is formed to project. The positioning protrusion 16 is formed integrally with the inner seal protrusion 12 on the outer surface side of the inner seal protrusion 12. The positioning protrusion 16 is formed at a position where the lower surface 16a contacts the opening end 20b when the cap 1 is mounted on the container mouth 20. The positioning protrusion 16 is
It may be formed in a continuous annular shape in the circumferential direction, or may be formed in a discontinuous annular shape composed of a plurality of island-shaped projections along the circumferential direction.

The height A of the positioning protrusion 16 is 0.2 to
It is preferably 1.5 mm (preferably 0.5 to 1 mm). If the height A is less than this range, the opening torque tends to be excessive, and if the height A exceeds this range, the sealing performance tends to deteriorate. Width B of positioning protrusion 16
Is 0.5 to 1.5 mm (preferably 0.7 to 1.3 m
m) is preferred.

The operation of the cap 1 when the cap 1 of the present embodiment is attached to the container mouth portion 20 will be described below with reference to FIGS. 3 and 4. The cap 1 to the container mouth 20
The inner seal protrusion 12 is fitted into the container mouth portion 20 and is abutted on the inner peripheral surface 20a of the container mouth portion 20 without a gap.

When the inner seal protrusion 12 is fitted in the container mouth portion 20, the inner seal protrusion 12 is elastically reduced in the base portion 12b in the radial direction (the direction in which the tip 12c moves radially inward). It is bent and deformed (see FIG. 3). As a result, the inner seal projection 12 has a smaller outer diameter and can be fitted into the container opening 20. Since the inner seal projection 12 fitted in the container mouth 20 is elastically deformed in the diameter reducing direction, the elastic restoring force applies a pressing force to the container mouth 20 in the diameter expanding direction.

As the cap 1 rotates, the container mouth 20
The outer peripheral edge portion 20c of the open end 20b comes into contact with the inner surface of the expanded tubular portion 13b of the open end seal projection 13 and applies upward force (see FIG. 3). Expansion container 1 by container opening 20
By applying an upward force to 3b, a force in the radial direction is applied to the opening end seal projection 13, and the opening end seal projection 13 is bent and deformed in the radial direction at the base end portion 13c, and the distal end side has a radial diameter. Move outward in the direction.

As shown in FIG. 4, when the cap 1 is further rotated, the opening mouth seal projection 13 is further bent and deformed in the radial expansion direction by the container mouth portion 20, and the tip portion 13e is changed to the cap body 4 (in the example shown in the figure). Abut the reinforcing wall portion 14).
In this state, the outer peripheral edge portion 20c of the opening end 20b applies a pressing force to the upright tubular portion 13a in an obliquely upward direction, and the reinforcing wall portion 14 exerts a drag force in an obliquely downward direction on the expansion tubular portion 13b. As a result, the open end seal projection 13 is slightly bent and deformed so as to project outward at the lengthwise intermediate portion. Therefore, the opening end seal projection 13 is bent and deformed outward at the base end portion 13c, and is also bent and deformed outward at the intermediate portion in the length direction. Therefore, the opening end seal projection 13 is pressed against the outer peripheral edge portion 20c by its elastic restoring force,
The container mouth 20 is sealed by contacting the outer peripheral edge 20c without a gap. At this time, since the opening end sealing protrusion 13 contacts not the entire opening end 20b but a narrow range including the outer peripheral edge portion 20c, the force applied to the opening end 20b by the opening end sealing protrusion 13 is concentrated near the outer peripheral edge portion 20c. Works.

In the state shown in FIG. 4, the opening end 20b of the container mouth 20 is in contact with the lower surface 16a of the positioning projection 16. Thereby, the height position of the cap 1 with respect to the opening end 20b is determined, and the distance between the top plate portion 2 and the opening end 20b becomes a predetermined value. Therefore, the amount of deformation of the opening end seal projection 13 has a predetermined value, and the pressing force of the opening end seal projection 13 against the opening end 20b has a predetermined value. The container 21 is hermetically sealed by mounting the cap 1 on the container opening 20 through the above process.

When the cap 1 attached to the container mouth 20 is rotated in the opening direction, a large number of tabs 11 provided on the inner surface of the TE ring portion 9 are locked to the lower end of the bulging step 23 of the container mouth 20. Therefore, the main portion 8 of the cap body 4 rises as it rotates, while the TE ring portion 9 is prevented from moving upward, and as a result, the main portion 8 of the cap and the TE ring portion 9 are connected. A tensile force acts on a large number of thin bridges 7, the bridges 7 are broken, the TE ring portion 9 is separated from the main portion 8, and the cap 1 is opened.

In the cap 1 of this embodiment, the top plate portion 2
In addition, since the positioning projection 16 that comes into contact with the opening end 20b when the opening end sealing projection 13 is bent and deformed until it comes into contact with the cap body 4, the top plate portion 2 and the opening end 20b are attached when the cap is attached. And the pressing force of the opening end seal projection 13 against the opening end 20b can be set to a predetermined value. Therefore, sufficient sealing performance can be obtained. In addition, the top plate 2 and the opening end 20
Since the distance from b can be set to a predetermined value, the tightening angle when the cap is attached can be set to a predetermined value.
Therefore, the opening torque can be set to an appropriate value.

The locking means of the tamper evidence ring 9 is not limited to the tab 11 in the above-mentioned embodiment, and for example, the Japanese Patent Application No. 8-
Type including wing and bead described in Japanese Patent No. 46445, Japanese Patent Application Nos. 6-228514 and 6-2466.
No. 19, No. 6-275415, No. 6-307804.
No. 6-313837, No. 7-84315, No. 7
It is also possible to employ a locking means that combines a locking claw on the container side and a locking protrusion on the tamper evidence ring described in No. 109850.

[0025]

As described above, in the cap made of synthetic resin of the present invention, the top plate portion is provided with the positioning projection that abuts the opening end. Sufficient sealing performance can be obtained by setting the distance from the end to a predetermined value and the pressing force of the opening end seal projection against the opening end to a predetermined value. Further, since the distance between the top plate portion and the opening end can be set to a predetermined value, the winding angle when the cap is attached can be set to a predetermined value, and the opening torque can be set to an appropriate value.

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view of a part of the synthetic resin cap shown in FIG.

FIG. 3 is a process diagram showing a process of mounting the synthetic resin cap shown in FIG. 1 on a container opening.

FIG. 4 is a process diagram showing a state in which the synthetic resin cap shown in FIG. 1 is attached to a container mouth.

[Explanation of symbols]

1 ... Cap, 2 ... Top plate part, 3 ... Cylinder part, 4 ... Cap body, 12 ... Inner seal protrusion, 13 ... Open end seal protrusion, 16 ... Positioning Convex portion, 20 ... Container opening portion, 20b
... Open end, 21 ... Container

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masataka Kuno             148 Nogi, Nogi-cho, Shimotsuga-gun, Tochigi             Shibasaki Manufacturing Co., Ltd. F-term (reference) 3E084 AA04 AA12 AA24 AB01 BA01                       CA01 CC03 DA01 DB12 DC03                       EA04 EC03 FA09 FB01 GA04                       GB04 GB08 HA03 HB02 HC03                       HD01 LA01 LA17

Claims (3)

[Claims] 1. A synthetic resin cap in which an annular inner seal protrusion fitted into a container mouth is formed on the inner surface of the top plate portion of a cap body having a top plate portion and a cylindrical portion hanging from the periphery thereof. Then, on the inner surface of the top plate portion, an annular opening end sealing projection that abuts the opening end of the container opening portion is formed, and when the opening end sealing projection is attached to the container opening portion, The container mouth is designed to bend and deform in the radial direction until it comes into contact with the cap body, and the top plate has a positioning projection that comes into contact with the opening end when the opening end seal projection is bent and deformed until it comes into contact with the cap body. A cap made of synthetic resin, which is provided with a portion. 2. The synthetic resin cap according to claim 1, wherein the positioning protrusion is provided integrally with the inner seal protrusion. 3. The opening-end sealing projection includes an upright tubular portion extending downward from the top plate portion, and an expansion tubular portion extending from the upright tubular portion in a skirt shape.
Or the synthetic resin cap described in 2.