JP3303121B2 - Method for producing container lid made of synthetic resin having tamper-evident properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a synthetic resin container lid having a tamper-evident property (a characteristic in which traces of an improperly opened container remain on the container lid).

[0002]

2. Description of the Related Art As a well-known container lid applied to the mouth and neck of a glass or synthetic resin container for a soft drink or the like, a synthetic resin container lid having a tamper-evident characteristic is widely used. Have been. A typical example of such a synthetic resin container lid includes a container lid body formed of a suitable synthetic resin such as polypropylene or hard polyethylene. The container lid body has a top wall and a skirt wall hanging down from the periphery of the top wall, and a circumferential break line is formed on the skirt wall, and the skirt wall is a main part above the break line. It is partitioned into a tamper-evident hem below the break line. The circumferential breaking line is composed of a plurality of circumferentially spaced slits extending in the circumferential direction and a plurality of bridging portions remaining between the slits, and the tamper-evident foot has a plurality of hem portions. It is connected to the lower part of the skirt wall via a bridge.
A female thread is formed on the inner surface of the main part of the skirt wall. A locking flap piece protruding radially inward is formed on the inner surface of the tamper-evident skirt. Usually, an axial breaking line is formed at the tamper-evidence foot, and in this case, one (or several) of the plurality of bridging portions in the circumferential breaking line has a breaking strength of another bridge. The non-ruptured bridging part is larger than the bridging part. A liner, conveniently made of a relatively soft synthetic resin such as soft polyethylene or EVA (ethylene-vinyl acetate copolymer), is usually provided on the inner surface of the top wall.

[0003] The container lid as described above is applied to a container in which a male screw and an annular locking jaw located below the male screw are formed on the outer surface of a cylindrical mouth and neck. When sealing the mouth and neck of the container, the container lid is fitted over the mouth and neck of the container and rotated in the closing rotation direction, and the female screw thread formed on the inner surface of the main part of the skirt wall in the container lid body. Into the male thread formed on the outer surface of the mouth and neck. The locking flap piece formed on the inner surface of the tamper-evidence hem of the container lid body is elastically deformed, passed through the annular locking jaw formed on the outer surface of the mouth and neck, and then elastically deformed. And is locked to the lower surface of the annular locking jaw. When the container lid is attached to the mouth and neck as required, a liner disposed on the inner surface of the top wall of the container lid body is brought into close contact with the upper end of the mouth and neck, thereby sealing the mouth and neck. When opening the mouth and neck of the container, the container lid body is rotated in the direction opposite to the closing rotation direction, that is, in the opening rotation direction. Thus, since the female thread formed on the skirt wall of the container lid body is moved along the male thread formed on the mouth and neck, the container lid moves along the axis in the opening rotation direction. It is moved upward in the direction. However, since the locking flap piece formed on the inner surface of the tamper-evidence hem is locked to the annular locking jaw of the mouth and neck, the tamper-evidence hem moves upward in the axial direction. Along with the circumferential break line formed on the skirt wall, considerable stress is generated in the axial break line formed on the tamper-evidence hem, and the bridging portion in the circumferential break line is unbroken. At the same time, the rupture of the tamper-evident dent is made from an endless annular shape to a stripped shape. After a while, the tamper-evidence skirt is also allowed to freely rise upward in the axial direction,
The entire container lid is removed from the mouth and neck, and the mouth and neck are opened. If the tamper-evident hem does not have an axial break line, all bridging portions in the circumferential rupture line are broken, the tamper-evidence hem is separated from the main part of the skirt wall, and the tamper-evident hem is cut off. The other part of the container lid is removed from the mouth and neck, leaving the skirt of the evidence on the mouth and neck.

[0004]

In the container lid of the above-described embodiment, the container lid is detached from the mouth and neck part without breaking the normal bridging part (and the axial line) at the circumferential breaking line. It is important that the so-called container lid slip-through is reliably prevented from occurring. If the container lid slips through, it is possible to open the mouth and neck once, make unauthorized changes to the contents, then reattach the container lid to the mouth and neck and return to the original state, Properties are impaired. Furthermore, the container lid cannot be detached from the mouth and neck, but the container lid is rotated through an angle of, for example, 360 degrees, thereby separating the liner upward from the upper end of the mouth and neck and sealing the mouth and neck. Is canceled once,
Prior to this, it is also important that the bridging part in the circumferential breaking line is broken. If the bridging part in the circumferential breaking line is not broken even though the seal of the mouth and neck has been once broken, the contents may be corroded due to the break of the seal of the mouth and neck once. When the inconvenience occurs, there is a possibility that a situation may occur in which the inconvenience is not specified and the product is sold as a normal product.

However, in the conventional container lid of the above-described embodiment, the locking flap piece formed on the tamper-evident hem of the container lid body is moved to the annular locking jaw formed on the mouth and neck. Is not always sufficient, and the above-mentioned requirements cannot be sufficiently satisfied. For example, the locking flap piece passes through the locking jaw of the mouth and neck by being elastically bent with its base edge, that is, the connection edge with the inner surface of the tamper-evident hem as a bending edge,
Thus, the above-mentioned detachment of the container lid often occurred. In order to solve such a problem, in a container lid disclosed in Japanese Utility Model Laid-Open No. 5-13957, an annular shape that extends substantially horizontally inward in the radial direction from the lower end of the inner surface of the tamper-evident hem portion. A reinforcement bead is formed. In such a container lid, the locking action of the locking flap piece is reinforced by an annular reinforcing bead located below the locking flap piece, in other words, the locking flap piece is elastically bent with its base edge as a bent edge. Is effectively prevented by the annular reinforcing bead located below the locking flap piece, increasing the locking action of the locking flap piece against the annular locking jaw formed on the mouth and neck of the container. The container is thus prevented from slipping through the container.

In the above-described container lid disclosed in Japanese Utility Model Laid-Open No. 5-13957, the tamper-evident hem extends substantially horizontally inward in the radial direction from the inner surface of the skirt. Due to the annular reinforcing bead, so-called undercuts are excessively generated in the container lid body, and in particular, the annular reinforcing bead is located close to the lower edge or the lower surface of the locking flap piece formed on the inner surface of the tamper-evident hem. Is positioned, there arises a problem that when the container lid body is formed by compression molding or injection molding, it becomes extremely difficult to remove the container lid body from the mold. If the axial distance between the lower end or lower surface of the locking flap piece formed on the inner surface of the tamper-evidence hem and the annular reinforcing bead is set relatively large, considerable forcible removal is required, but the container lid body is removed from the mold. It becomes possible to take out. However, when the axial length of the lower edge or lower surface of the locking flap piece and the annular reinforcing bead increases, the reinforcing effect of the annular reinforcing bead on the locking flap piece is reduced, and the above-mentioned container cover slip-through can be sufficiently eliminated. Can not be prevented.

The present invention has been made in view of the above-mentioned facts, and a technical problem of the present invention is to provide a sufficient locking action of a locking flap piece to an annular locking jaw formed on the mouth and neck of a container. An object of the present invention is to manufacture a container lid having a reinforcing bead without reinforcing the container lid main body from the mold without making it extremely difficult.

[0008]

As a result of intensive studies and experiments, the present inventors have found that the reinforcing beads formed on the inner surface of the skirt portion of the tanta-evident are not substantially horizontal but radially downward in the axial direction. In the main body forming step, a container lid main body having an inwardly extending and extending form is formed, and after the main body forming step, a heated pressing tool is applied to the reinforcing bead to substantially move the reinforcing bead radially inward. It has been found that the above technical problem can be achieved by performing a reinforcing bead deforming step of deforming to a state of extending horizontally upward or inclining upward in the axial direction.

That is, according to the present invention, as a manufacturing method for achieving the above technical problem, there is provided a top wall and a skirt wall hanging down from the periphery of the top wall, wherein the skirt wall is composed of a main portion and the main portion. And a tamper-evident skirt positioned below the tamper-evident skirt, wherein a locking flap protruding inward in the radial direction is provided on an inner surface of the tamper-evident skirt. In a method for manufacturing a synthetic resin container lid having tamper-evident properties, the method includes a molding step, wherein the container lid main body molded in the main body molding step has the tamper-evident foot below the locking flap piece. A reinforcing bead extending inclining radially inward from the inner surface of the part toward the axial direction downward is provided,
After the main body forming step, the heated pressing tool is applied to the reinforcing bead to deform the reinforcing bead so as to extend substantially horizontally or inclining upward in the axial direction toward the radially inward direction. A manufacturing method including a bead deformation step is provided.

[0010] The radius of the inner surface of the tamper-evident hem of the container lid body formed in the main body forming step below the reinforcing bead is a predetermined value x larger than the radius of the inner surface above the reinforcing bead. The predetermined value x is preferably substantially the same as or slightly larger than the thickness of the reinforcing bead. On the inner surface of the tamper-evident hem, a plurality of the locking flap pieces are disposed at intervals in the circumferential direction, and each of the locking flap pieces is a base connected to the tamper-evident hem. When the container lid is attached to the mouth and neck of the container from the edge, the container lid is inclined in a direction opposite to the closing rotation direction and is projected inward in the radial direction, and the base edge is directed downward in the axial direction. When extending in a direction opposite to the container lid closing rotation direction, it is advantageous that the reinforcing bead is pressed against the lower edge of the locking flap piece in the reinforcing bead deformation step, and A plurality of grooves are formed on the upper surface of the reinforcing bead of the container lid main body formed in the main body forming step, and the reinforcing bead is pressed against the lower edge of the locking flap piece in the reinforcing bead deforming step. The locking flag It is advantageous lower edge of the flop pieces are housed in the groove. In the case where the base edge of the locking flap piece formed on the inner surface of the tamper-evident hem portion connected to the tamper-evidence hem portion extends substantially horizontally, the reinforcing bead deformation step The reinforcing bead can be pressed against the lower surface of the locking flap piece.

[0011]

In the manufacturing method of the present invention, since the reinforcing beads of the container lid main body formed in the main body forming step are not substantially horizontal inward in the radial direction but extend obliquely downward in the axial direction, the reinforcing beads are reinforced. The undercut generated due to the bead can be made sufficiently small, so that the container lid main body can be easily detached from the mold without excessively forcibly removing in the container lid main body forming step. In the reinforcing bead deformation step performed after the container lid body forming step, the reinforcing bead is deformed so as to extend substantially inward in the radial direction or incline upward in the axial direction, and thus the locking flap piece formed by the reinforcing bead. The reinforcement effect of the stiffness is made sufficient.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the manufacturing method according to the present invention will be described below in more detail with reference to the accompanying drawings.

FIG. 1 shows a preferred example of a synthetic resin container lid main body formed by a main body forming step. The container lid body indicated by reference numeral 2 includes a substantially circular top wall 4 and a substantially cylindrical skirt wall 6 hanging from the periphery of the top wall 4. The skirt wall 6 has a main portion 8 and a tamper-evident hem portion 10 located below the main portion 8. The outer surface of the main portion 8 of the skirt wall 6 is formed with an uneven shape 12 for preventing a finger locked therefrom from slipping. A female thread 14 is formed on the inner surface of the main portion 8 of the skirt wall 6. An axially extending ventilation cutout 16 is formed in the female thread 14 at intervals in the circumferential direction.
A plurality of locking flap pieces 18 are formed on the inner surface of the tamper-evident hem portion 10 at intervals in the circumferential direction. Each of the locking flap pieces 18 starts from a base edge 20 connected to the inner surface of the tamper-evident hem portion 10, as described later, when the container lid 2 is attached to the mouth and neck of the container. It is inclined in the opposite direction to the closing rotation direction (clockwise as viewed from above in FIG. 1) and protrudes radially inward. Base 2 of each of locking flap pieces 18
0 itself also extends obliquely downward in the axial direction and in the opposite direction to the container lid closing rotation direction.

In the container lid main body 2 formed by the container lid main body manufacturing step in the manufacturing method according to the present invention,
A reinforcing bead 22 extending from the inner surface of the tamper-evident skirt 10 to the axially downward direction and inclined inward in the radial direction.
It is important that is formed. The reinforcing bead 22 in the illustrated embodiment has a circumferentially continuous annular shape, and extends obliquely inward in the radial direction from the upper end edge adjacent to the lower end edge of the locking flap piece 18 downward in the axial direction. . The inclination angle α of the reinforcing bead 22 with respect to the axis extending vertically is preferably 20 to 40 degrees, particularly preferably 25 to 35 degrees. In the illustrated embodiment, further, the portion of the tamper-evident hem portion 10 below the reinforcing bead 22 is reduced in thickness, and the inner surface radius R1 of the tamper-evident hem portion 10 below the reinforcing bead 22 is reduced. Is longer than the radius R2 of the inner surface above the reinforcing bead 22 by a predetermined value x. Conveniently, the predetermined value x is set substantially equal to or slightly larger than the thickness of the reinforcing bead 22 itself.

FIG. 2 shows the container lid main body 2 shown in FIG. 1 and a mold used for compression-molding the container lid main body 2. A molding die generally designated by numeral 24 for compression-molding the container lid body in an inverted state (that is, a state in which the top wall 4 faces downward) is composed of a lower mold member 26 and four upper cooperating members. The mold includes an outer annular member 28, an intermediate annular member 30, an intermediate annular member 32, and a central mold member 34. The lower mold member 26 defines the entire outer surface of the container lid body 2, that is, the outer surface of the top wall 4 and the outer surface of the skirt wall 6, and the outer annular mold member 28 defines the skirt wall 6.
2 (an end surface located at the upper end in the inverted state shown in FIG. 2), and the intermediate annular member 30 is provided at the upper end portion (in the inverted state shown in FIG. 2) of the tamper-evident hem portion 10 in the skirt wall 6. In the state, the inner surface other than the lower end is defined, and the intermediate annular member 32 is the upper end (shown in FIG. 2) of the main portion 8 in the skirt wall 6 together with the inner upper end of the tamper-evident hem 10 in the skate wall 6. The center mold member 34 defines the inner surface of the top wall 4 together with the inner surface of the upper end of the main portion 8 of the skirt wall 6 in the inverted state. When the container lid main body 2 is compression-molded using the molding die 24, the outer annular mold member 28, the intermediate annular mold member 30, the intermediate annular mold member 32, and the central mold member 34 are moved relative to the lower mold member 26. In a state of being relatively raised and separated from the lower mold member 26, a softened and molten synthetic resin material is supplied into the lower mold member 26, and thereafter, the outer annular mold member 28 and the intermediate annular mold are provided. The member 30, the intermediate annular mold member 32, and the center mold member 34 are lowered relative to the lower mold member 26 to the position shown in the drawing, and thus the container lid body 2 is compression molded. As a synthetic resin material for forming the container lid body 2, a relatively hard synthetic resin such as polypropylene or hard polyethylene is preferably used. The removal of the container lid body 2 from the molding die 24 is performed in the following procedure. First, the outer annular member 28 together with the container lid body 2,
The intermediate annular mold member 30, the intermediate annular mold member 32, and the central mold member 34 are raised relatively to the lower mold member 26, and the lower mold member 26 is detached from the container lid body 2. Next, the annular intermediate mold member 30 is raised relatively to the container lid body 2 and the outer annular mold member 28, the intermediate annular mold member 32, and the central mold member 34, and the intermediate annular mold member 30 is removed from the container lid body 2. You will be separated. Next, the intermediate annular mold member 32 is raised relatively to the container lid main body 2, the outer annular mold member 28, and the central mold member 34, and the intermediate annular mold member 32 is detached from the container lid main body 2. Thereafter, the central mold member 34 is raised relatively to the container lid body 2 and the outer annular mold member 28, the central mold member 34 is detached from the container lid body 2, and the container lid body 2 is The container lid body 2 is dropped downward from the mold member 28, and
Taken out of

Referring to FIG. 1 together with FIG. 2, when the intermediate annular member 30 is lifted relatively to the container lid body 2 and detached from the container lid body 2,
The intermediate annular member 30 is rotated somewhat counterclockwise as viewed from above in FIG. 2, while each of the locking flap pieces 18 formed on the inner surface of the tamper-evident skirt 10 has its base edge 20 The center is pivoted downward (upward in the inverted state shown in FIG. 2). The deformation due to the rotation such as the locking flap piece 18 is obtained by removing the container lid body 2 from the mold 24 and inserting a cylindrical correction tool into the container lid body, for example, to move the locking flap piece 18 to a required position. It can be corrected by forcibly returning it. (Deformation due to turning of the locking flap piece 18 and its correction are described in detail in Japanese Patent Application Laid-Open No. 58-51116. Detailed description is omitted). On the other hand, a reinforcing bead 22 is formed on the inner surface of the tampon-evident skirt 10, and when the intermediate annular member 30 is raised relatively to the container lid body 2 due to the presence of the reinforcing bead 22. Is generated with no force. However, since the reinforcing bead 22 is inclined inward in the radial direction toward the lower side in the axial direction (upward in the inverted state shown in FIG. 2), it is impossible to forcibly generate the reinforcing bead 22. The degree is relatively small, and the intermediate annular member 30 can be easily detached from the container lid main body 2 easily without undesired deformation of the reinforcing bead 22. In particular, in the illustrated embodiment, as described above, the inner radius R1 below the reinforcing bead 22 in the tamper-evident hem portion 10 is made longer than the inner radius R2 above the reinforcing bead 22 by a predetermined value x. Since the predetermined value x is set to be substantially the same as or slightly larger than the thickness of the reinforcing bead 22, the reinforcing bead 22 is sufficiently easy to separate the intermediate annular member 30 from the container lid body 2. The intermediate annular member 30 can be easily detached from the container lid main body 2 from the fact that it is bent radially outward and extends along the inner surface of the lower end of the tamper-evident hem 10. When the intermediate annular member 32 is lifted up relative to the container lid body 2 to be detached from the container lid body 2, the intermediate annular member 32 is also caused by the female thread 14 formed on the inner surface of the main portion 8 of the skirt wall 6. However, the degree of such forcing is relatively small, and the intermediate annular member 32 can be detached from the container lid body 2 easily enough.

Continuing with reference to FIG. 1, in the illustrated embodiment, a break line forming step is performed after the main body forming step, whereby the circumferential break line 36 is formed.
And an axial breaking line 38 is formed. A circumferential breaking line 36 that divides the skirt wall 6 into the main portion 8 and the tamper-evident hem portion 10 has a plurality of slits 40 extending in the circumferential direction at intervals in the circumferential direction and a plurality of slits 40 located between the slits 40. And the bridging portions 42.
One of the plurality of bridging portions 42 is a non-ruptured bridging portion 42A having a larger cross-sectional area than other bridging portions to increase strength. If desired, all bridging portions 42 can be broken bridging portions without providing the non-breaking bridging portions 42A, in which case the provision of the axial breaking line 38 can be omitted. it can. Still referring to the formation of the circumferential break line 36, in the illustrated container lid body 2, the inner surface of the skirt wall 6 has a downwardly facing annular shoulder 4 thereon.
4 is formed, and the inner diameter below the annular shoulder portion 44 is set somewhat larger than the inner diameter above it. Immediately below the annular shoulder 44, a plurality of axially extending ribs 46 are formed on the inner surface of the skirt wall 6 at circumferentially spaced intervals.
The circumferential breaking line 36 is formed by cutting the skirt wall 6 in the circumferential direction while leaving the ribs 46. Such a cut made from the outer surface of the skirt wall 6 is not entirely cut in the circumferential direction, but is left partially without being cut in the circumferential direction. Accordingly, the tamper-evident foot portion 10 below the circumferential breaking line 36 is separated from the circumferential cutting line 36 through the plurality of ribs 46 and the circumferential non-cutting portions that are left without being cut. Is also connected to the upper main part 8. The plurality of ribs 46 define a normal bridging portion 42, the cutting line between the plurality of ribs 46 defines a slit 40, and the circumferential non-cutting portion defines a non-ruptured bridging portion 42A. . Above axial breaking line 3
Numeral 8 extends along the tamper-evident hem portion 10 in the axial direction, and the upper end thereof is brought close to one end of the non-ruptured bridging portion 42A. Such axial rupture lines 38 may be conveniently constructed from scores generated by cutting partially from the inner or outer surface of the tamper-evidence skirt 10 in the thickness direction rather than the entire thickness direction. The breaking line forming step for forming the circumferential breaking line 36 and the axial breaking line 38 may be performed after or between the reinforcing bead deformation step and the liner molding step described later, if desired, instead of before. You can also. Furthermore,
In the illustrated embodiment, the cutting operation is performed to form the circumferential rupture line 36 and the axial rupture line 38 in a rupture line forming step performed separately from the main body forming step. The slit in the circumferential breaking line and the score (or slit) in the axial breaking line can also be formed during compression molding or injection molding in the main body molding step.

In the present invention, it is important to perform a reinforcing bead deformation step after the main body forming step. Continuing the description with reference to FIGS. 3 and 4, in the reinforcing bead deformation step, the container lid body 2 is held in an inverted state by a suitable holding means (not shown), and is pressed against the container lid body 2. A tool 48 is applied. This pressing tool 4
A cylindrical pressing ridge 50 is formed on the lower end surface of the cylindrical member 8.
The outer diameter of the pressing ridge 50 is substantially the same as or slightly smaller than the inner diameter of the lower end (the upper end in the inverted state shown in FIGS. 3 and 4) of the tamper-evident hem 10 in the container lid body 2. The pressing tool 48 is heated by an appropriate heating means (not shown), and the pressing ridge 50 is heated to a required processing temperature (for example, about 110 to 120 degrees when the container lid body 2 is made of polypropylene). 4) and inserted into the container lid body 2 until the state shown in FIG.
2 is pressed. Thus, the reinforcing bead 22 is heated and deformed into a state in which the reinforcing bead 22 extends substantially horizontally or inclining upward in the axial direction (axially downward in the inverted state shown in FIGS. 3 and 4) inward in the radial direction. It is pressed against the lower edge of the stop flap piece 18.

In the illustrated embodiment, a liner forming step is further performed after the reinforcing bead deformation step, and as shown by a two-dot chain line in FIG. A liner 52 is formed. In a preferred example of such a liner molding step, a synthetic resin material in a softened and molten state is supplied to the inner surface of the top wall 4 of the container lid main body 2, and then a compression molding tool (not shown) enters the container lid main body 2. At the very least, it acts on the synthetic resin material to flow into a required shape, and thus the liner 52 is formed. As a synthetic resin material for forming the liner 52, a relatively soft synthetic resin such as soft polyethylene or EVA (ethylene-vinyl acetate copolymer) is conveniently used. If desired, a liner forming step can be performed prior to or between the breaking line forming step and the reinforcing bead deforming step described above.

FIG. 5 shows a state in which the container lid 54 made of the container lid main body 2 and the liner 52 manufactured through the above-described various steps is attached to the mouth and neck portion 56 of the container. . The mouth and neck portion 56 of the container, which can be formed from a suitable synthetic resin such as glass or polyethylene terephthalate, has a substantially cylindrical shape as a whole, and has an external thread 58 on its outer surface and an annular locking jaw located below it. A part 60 is formed. After filling the container with required contents such as soft drinks, the container cover 54 is attached to the mouth and neck portion 56, and the mouth and neck portion 56 is sealed. When attaching the container lid 54 to the mouth and neck 56, the container lid 54 is fitted to the mouth and neck 56, and the container lid 54 is rotated in the closing rotation direction, that is, clockwise as viewed from above in FIG. Thus, the female screw thread 14 formed on the inner surface of the main portion 8 of the skirt wall 6 of the container lid body 2 is replaced with the male screw thread 58 formed on the outer peripheral surface of the mouth and neck portion 56 of the container.
And screw them together. The locking flap piece 18 formed on the inner surface of the tamper-evident hem portion 10 of the skirt wall 6 of the container lid body 2 is elastically deformed upward to form the annular locking jaw portion 60 of the mouth and neck portion 56. After passing, it is elastically restored and locked on the lower surface of the annular locking jaw 60. The liner 52 formed on the inner surface of the top wall 4 of the container lid body 2 is brought into close contact with the upper end surface of the mouth-neck portion 56, whereby the mouth-neck portion 56 is sealed.

When opening the mouth and neck portion 56 of the container, the container lid 54 is rotated in the opening rotation direction, that is, counterclockwise as viewed from above in FIG. As a result, the female thread 14 formed on the inner surface of the main part 8 of the skirt wall 6 of the container lid body 2 is moved along the male thread 58 formed on the outer peripheral surface of the mouth-neck portion 56. The container lid 54 is raised with rotation. On the other hand, the tamper-evident hem portion 10 in the skirt wall 6 of the container lid body 2 is formed by an annular locking jaw portion 60 in which the locking flap piece 18 formed on the inner surface is formed on the outer peripheral surface of the mouth and neck portion 56. Is locked to the lower surface of the, so that upward movement is prevented. Thus, a considerable stress is generated at the bridging portion 42 in the circumferential breaking line 36 formed on the skirt wall 6 of the container lid main body 2, and all the bridging portions 42 except the non-breaking bridging portion 42A are broken. You. Further, considerable stress is also generated in the axial breaking line 38 formed in the tamper-evident foot portion 10, and the axial breaking line 38 is broken. Thus, the tamper-evident hem portion 10 is developed from the endless annular shape to the end band shape, the locking of the locking flap piece 18 to the annular locking chin portion 60 of the mouth and neck portion 56 is released, and the tamper-evident hem portion 10 is released. , The entire container lid 54 can be raised. When the container lid 54 is raised to a certain extent, the liner 52 of the container lid 54 is separated from the upper end of the mouth and neck portion 56, and is formed between the upper end of the mouth and neck portion 56 and the liner 52 and on the female thread 14. The inside of the container is communicated with the outside through the vent notch 16 (FIG. 1). Thereafter, the entire container lid 54 is detached from the mouth and neck 56, and the mouth and neck 56 is completely opened.

Thus, the tamper-evident foot portion 10 of the container lid main body 2 manufactured by the manufacturing method of the present invention is provided.
In the container lid 54 in which the reinforcing bead 22 extending substantially horizontally or inclining upward in the axial direction is formed inward in the radial direction, the container lid 54 is rotated in the opening rotation direction, and the mouth and neck portion 56 is rotated. Upon opening, the presence of the reinforcing bead 22 pressed against the lower edge of the locking flap piece 18 causes the locking flap piece 18 to pivot downward about its base edge 20 to form Locking jaw 60
Is reliably prevented from passing through the circumferential breaking line 3
6, it is possible to prevent the container lid 54 from being detached from the mouth-neck portion 56 without breaking the bridging part 42 and the axial breaking line 38. In addition, the presence of the reinforcing bead 22 pressed against the lower edge of the locking flap piece 18 enhances the locking of the locking flap piece 18 to the annular locking jaw 60 of the mouth-neck portion 56, so that the inside of the container The requirement that the bridging portion 42 and the axial breaking line 38 in the circumferential breaking line 36 be broken before the outside is communicated to the outside can be relatively easily satisfied.

FIGS. 6 and 7 show a modification of the reinforcing bead in the container lid manufactured by the manufacturing method of the present invention. In the modification shown in FIG. 6, a large number of grooves 123 are formed on the upper surface of the reinforcing bead 122 at intervals in the circumferential direction. The groove 123 located below each of the locking flap pieces 118 extends along the lower edge of the locking flap piece 118. In the reinforcing bead deformation step, the reinforcing bead 122 is formed on the lower edge of the locking flap piece 118. When pressed, the lower edge of the locking flap piece 118 is
3 In the modified example shown in FIG. 7, a plurality of reinforcing beads 222 extending in an arc shape are formed at intervals in the circumferential direction instead of the reinforcing beads extending in a ring shape continuously in the circumferential direction. Each of the reinforcing beads 222 is disposed below each of the locking flap pieces 218 so as to correspond to each of the locking flap pieces 218.
22 have locking flap pieces 218 located above them.
Pressed against the lower edge of each.

FIG. 8 shows a modified example of the container lid main body formed in the main body forming step. In the container lid body 302 shown in FIG. 6, a locking flap piece 318 extending continuously in the circumferential direction is formed on the inner surface of the tamper-evident hem 310 in the skirt wall 306. The locking flap piece 318 is inclined upward and protruded inward in the radial direction from the base edge 320 connected to the tamper-evident hem portion 310. The base edge 320 of the locking flap piece 318 extends substantially horizontally. Notches 319 are formed in the locking flap pieces 318 themselves at intervals in the circumferential direction. Each of the cutouts 319 extends to the protruding edge of the locking flap piece 318, and the circumferential width thereof is gradually increased toward the protruding edge. If desired, instead of circumferentially extending annular locking flap pieces 318, circumferentially spaced locking flap pieces projecting upwardly from the substantially horizontally extending base edge and projecting radially inward may be used. It is also possible to form a plurality. The configuration of the container lid body 302 shown in FIG. 8 except for the locking flap pieces 318 is substantially the same as the container lid body 2 shown in FIG.

The container lid body 302 shown in FIG. 8 is also identical to the container lid body 2 shown in FIG.
By performing the breaking line forming process, the circumferential breaking line 336 is formed.
And an axial break line 338 is formed, after which a reinforcing bead deformation step is performed. In the reinforcing bead deformation step, the heated pressing tool is used to
As shown by the two-dot chain line in FIG. 8, the reinforcing bead 322 is heated and deformed so as to extend inward in the radial direction substantially horizontally or inclining upward in the axial direction, and the locking flap piece is formed. 318 is pressed against the lower surface.
Then, a liner molding step is further performed, and the liner 35 is added to the inner surface of the top wall 304 of the container lid body 302 as required.
2 are formed.

[0026]

According to the manufacturing method of the present invention, a container lid provided with a reinforcing bead for sufficiently reinforcing the locking action of the locking flap piece to the annular locking jaw formed on the mouth and neck of the container. Can be manufactured sufficiently easily without the problem that the container lid main body is taken out of the mold in the main body molding step, which is accompanied by remarkable difficulty.

[Brief description of the drawings]

FIG. 1 is a side view, partially in section, of a container lid main body formed by performing a main body forming step and a break line forming step in a preferred embodiment of the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view illustrating the container lid main body illustrated in FIG. 1 together with a mold.

FIG. 3 is a partially enlarged view for explaining a reinforcing bead deformation step performed on the container lid main body shown in FIG. 1;

FIG. 4 is a partially enlarged cross-sectional view for explaining a reinforcing bead deformation step performed on the container lid main body shown in FIG. 1;

FIG. 5 is a side view, partially in section, showing a state in which the container lid manufactured by the preferred embodiment of the manufacturing method of the present invention is attached to the mouth and neck of the container.

FIG. 6 is a partial slope view showing a modified example of the reinforcing bead in the container lid manufactured by the preferred embodiment of the manufacturing method of the present invention.

FIG. 7 is a partial slope view showing still another modified example of the reinforcing bead in the container lid manufactured by the preferred embodiment of the manufacturing method of the present invention.

FIG. 8 is a side view, partially in section, of a modified example of the container lid main body formed by the container lid main body forming step and the retraction of the breaking line in the manufacturing method according to the present invention.

[Explanation of symbols]

 2: container lid body 4: top wall 6: skirt wall 8: main part of skirt wall 10: tamper evidence hem 14: female thread 18: locking flap piece 20: base edge of locking flap piece 22: reinforcement Bead 24: Container lid main body compression mold 26: Lower mold member 28: Outer annular mold member 30: Middle annular mold member 32: Middle annular mold member 34: Central mold member 36: Circumferential breaking line 38: Axial breaking line 48: pressing tool 50: pressing projection 52: liner 54: container lid 56: mouth and neck 58: male screw 60: annular locking jaw 118: locking flap piece 122: reinforcing bead 123: groove 218: locking Flap piece 222: Reinforcement bead 302: Container lid body 306: Skirt wall 310: Tamper evidence bottom 318: Locking flap piece 319: Notch 320: Base edge of locking flap piece 3 2: reinforcing beads 336: circumferential break line 338: axial breaking line 352: Liner

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-24458 (JP, A) JP-A-4-311461 (JP, A) JP-A-60-204315 (JP, A) 13957 (JP, U) Japanese Utility Model Hei 4-74644 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B65D 41/34

Claims (5)

(57) [Claims] The tamper shrimp includes a top wall and a skirt wall hanging down from a periphery of the top wall, the skirt wall including a main portion and a tamper-evident skirt positioned below the main portion. Including a main body molding step of molding a synthetic resin container lid body in which a locking flap protruding inward in the radial direction is provided on the inner surface of the dent hem portion, a synthetic resin container lid having tamper-evident characteristics. In the manufacturing method, the container lid main body formed in the main body forming step includes:
A reinforcing bead is provided below the locking flap piece and extends inclining radially inward from the inner surface of the tamper-evident skirt toward the axial direction downward. A reinforcing bead deforming step of causing the pressed bead to act on the reinforcing bead to deform the reinforcing bead so as to extend substantially horizontally or inclining upward in the axial direction toward the radially inward direction. Characteristic manufacturing method. 2. The rim of the tamper-evident hem of the container lid main body formed in the main body forming step, the radius of the inner surface below the reinforcing bead is more than the radius of the inner surface above the reinforcing bead. 2. The method according to claim 1, wherein the predetermined value x is substantially equal to or slightly larger than the thickness of the reinforcing bead. 3. The tamper-evident skirt has a plurality of locking flaps disposed on the inner surface of the tamper-evident skirt at intervals in a circumferential direction, and each of the locking flaps is a tamper-evident skirt. The base edge is inclined in the opposite direction to the container cover closing rotation direction when the container cover is attached to the mouth and neck of the container from the base edge connected to the container, and is projected inward in the radial direction. The reinforcing bead is pressed against a lower edge of the locking flap piece in the reinforcing bead deforming step, wherein the reinforcing bead is inclined downward in a direction opposite to the container lid closing rotation direction. 2. The production method according to 2. 4. A plurality of grooves are formed on an upper surface of the reinforcing bead of the container lid main body formed in the main body forming step, and the reinforcing bead is provided with the locking flap piece in the reinforcing bead deforming step. The manufacturing method according to claim 3, wherein the lower edge of the locking flap piece is housed in the groove by being pressed against the lower edge of the locking flap. 5. A base edge of the locking flap piece formed on an inner surface of the tamper-evident hem portion, which is connected to the tamper-evident hem portion, extends substantially horizontally, and the reinforcing bead deformation is performed. 3. The method according to claim 1, wherein the reinforcing bead is pressed against a lower surface of the locking flap piece in the step.