JP6715995B2 - Metal cap - Google Patents

Description

The present invention relates to a metal cap provided with a liner having a good sealing property and an unsealing property.

As a cap to be attached to the mouth and neck of a beverage container made of metal, synthetic resin such as polyethylene terephthalate, or glass, it has a circular top wall and a cylindrical skirt wall hanging down from the periphery of the top wall, and is made of an aluminum base. Metal caps having a cap body formed of a metal thin plate such as an alloy thin plate, a chromic acid treated steel thin plate, or a tin plate are widely used.
A liner molded from a synthetic resin such as polypropylene is provided on the inner surface of the top wall of the cap body.
Such a metal cap is a mouth cap that is filled with contents in a container and then fitted with a metal cap on the mouth neck, and the liner is pressed against the mouth neck to seal the mouth neck. A female thread is formed on the main part of the skirt wall along the male thread of the above, and the lower end of the skirt wall is deformed inward in the radial direction and locked to the annular jaw, and thus a metal cap is attached to the mouth and neck. Put on and seal the mouth and neck.

Japanese Patent No. 4585126 JP, 2013-189254, A

As the performance of the cap, openability and hermeticity are required. A liner made of synthetic resin such as polypropylene is used to seal the mouth and neck of a container, but generally, if the sealing property is improved, the unsealing property is impaired and the unsealing becomes difficult, especially the initial opening torque immediately before rotation. Becomes higher. On the other hand, if the unsealing property is improved so that it can be easily opened, the sealing force will be lost.
According to Patent Document 1, a metal circular thin plate-shaped reinforcing member is provided on the inner surface of the top surface wall of the cap body of the metal cap, and a synthetic resin liner is embossed on one side of the reinforcing member to form the top surface wall. A reinforcing member is provided on the side without adhering to the top wall, and a liner is brought into contact with the mouth and neck of the container. Therefore, the synthetic resin liner maintains the hermeticity of the mouth and neck, and at the time of opening, the inner surface of the top wall and the metal reinforcing plate are not adhered to each other, so that the top wall is made of metal. The opening force is reduced by reducing the frictional force on the contact surface with the reinforcing plate.

According to Patent Document 2, a synthetic resin liner is arranged on the inner surface of the top wall of the cap body of the metal cap. This synthetic resin liner is composed of multiple layers of a hard sheet made of polypropylene or the like arranged in contact with the inner surface of the top wall, and a soft layer laminated on one surface of the hard sheet by resin molding. In such a liner, the hard sheet is arranged without adhering to the top wall, and the soft layer is brought into contact with the mouth and neck of the container. Therefore, the softness of the mouth and neck is maintained, and when opening, the frictional force between the contact surface between the inner surface of the top wall and the hard sheet is reduced to reduce the opening force.

However, since the metal cap of Patent Document 1 uses a metal disc-thin plate-shaped reinforcing member, there is a problem that the cost is higher than that of a cap made of only synthetic resin. Further, in addition to a series of manufacturing processes such as molding of the cap body and embossing of the liner, a setting process work of inserting a reinforcing member obtained by molding the liner into the inside of the cap body has been added.
Similarly, regarding the metal cap of Patent Document 2, a liner including a hard sheet and a soft layer must be inserted into the inside of the cap body afterwards, and a setting process work other than the molding work is added.

The present invention has been made in view of such circumstances, and a liner retained in the cap body while being separated (non-adhered state) from the cap body is used in molding of the cap body and embossing of the liner. An object is to provide a metal cap that can be formed by a series of operations.

To achieve the above object, the metal cap of the present invention is disposed on the inner surface of the cap body having a circular top surface wall and a cylindrical skirt wall hanging from the peripheral edge of the top surface wall. A liner-made metal cap, comprising: a synthetic resin liner, wherein a liner holding portion for holding an edge portion of the liner is formed on the skirt wall so as to project outward in the radial direction. A two-layer structure comprising a barrier layer on the top wall side of the metal cap and a sealing layer on the inner side, which is formed by supplying a resin into the cap body and then press-molding the molten resin, A coating layer is formed on the inner surface of the cap body to make the inner surface and the barrier layer non-adhesive, and a molten barrier resin at the time of molding the barrier layer is temporarily formed on the surface of the coating layer. A molten resin rolling prevention means for locking the top wall is provided, and the liner is not attached to the top wall after the liner is molded and before the cap body is attached to the mouth and neck of the container. It was in a bonded state.
It is preferable that the rolling prevention means of the metal cap is formed in a central portion of an inner surface of the top wall.
The rolling prevention means of the metal cap is preferably a weak adhesive capable of peeling from the barrier layer.
The barrier layer of the metal cap may be formed of polypropylene, and the sealing layer may be formed of elastramer.
At the lower end of the liner holding portion of the metal cap, a holding protrusion that protrudes inward of the skirt wall and holds the liner at the inner peripheral surface is formed. Can also be formed with an inward projection that projects radially inward of the cap body.

According to the present invention, the liner retained in the cap body even though it is not adhered to the cap body is subjected to a series of operations in molding the cap body and embossing the liner, that is, in a separate step, the liner is attached to the cap body. It is possible to manufacture a metal cap capable of molding a molten resin in the cap body without pushing it into the cap body.
In addition, the cost can be reduced as compared with a metal thin plate and a hard sheet molded with a resin liner, while the opening torque is reduced as compared with a cap body to which a liner is bonded. be able to.

FIG. 3 is a partially cutaway front view of the metal cap according to the first embodiment of the present invention. 1A is an enlarged cross-sectional view of the metal cap of FIG. 1 around the top surface wall at the time of molding, and B is an enlarged cross-sectional view after molding. It is a partially broken front view of the metal cap of FIG. 1 before winding. FIG. 2 is a partially cutaway front view of the metal cap liner of FIG. 1 before molding. 1 shows the procedure for forming the barrier layer of the metal cap of FIG. 1, where A is a cross-sectional view of the barrier material being dropped on the top wall, B is a cross-sectional view of the barrier material being stretched by compression molding, and C is a compression molding. FIG. 6 is a cross-sectional view of a state in which the barrier material is molded into a barrier layer by molding. 1 shows a molding procedure of the sealing layer of the metal cap of FIG. 1, where A is a cross-sectional view of the ceiling material on which the sealing material is dropped on the barrier material, and B is a cross-section of the sealing material being stretched by compression molding. FIG. 3C is a cross-sectional view of a state in which the sealing material is molded into the sealing layer by compression molding. It is an expanded sectional view of the liner holding|maintenance part periphery of the metal cap of FIG. It is a partially broken front view of the state where the cap of FIG. 1 is opened. It is sectional drawing of the boundary part of the ceiling wall and skirt wall of the metal cap by the 2nd Embodiment of this invention. 2 shows a molding procedure of the metal cap of FIG. 2, A is a cross-sectional view of the cap body in a molded state, B is a cross-sectional view of the barrier body formed in the A cap body, and C is an inward direction in the B cap body. FIG. 6 is a cross-sectional view of a state in which a protrusion is formed, and D is a cross-sectional view of a state in which a sealing layer is formed on the barrier layer surface formed in C. It is a diagram showing a test example according to an embodiment of the present invention.

Hereinafter, a metal cap according to the present invention will be described in detail with reference to the accompanying drawings.
Referring to FIG. 1, a metal cap 1 which is a first embodiment of a metal cap according to the present invention includes a cap body 2 and a liner 3. The cap body 2 has a circular top wall 5 and a cylindrical skirt wall 6 that hangs from the peripheral edge of the top wall 5. An annular bulge 7 is formed in the lower part of the skirt wall 6 so as to bulge somewhat outward in the radial direction. A fracture line 8 is formed in the circumferential direction at the central portion of the annular bulging portion 7 in the axial direction. The skirt wall 6 is partitioned into a main portion 9 above the break line 8 and a tamper-evidence band 10 below the break line 8. The breaking line 8 is composed of a plurality of slits 11 extending in the circumferential direction at intervals in the circumferential direction, and a plurality of breakable bridging portions 12 located between the slits 11.

A liner holding portion 14 for holding the liner 3 is formed on the upper end of the skirt wall 6. The liner holding part 14 projects radially outward in an arc shape, and the lower part of the liner holding part 14 projects inward by projecting a region below the cutting line 15 engraved in the circumferential direction inward in the radial direction. A portion 16 (see FIG. 3) is formed, and the cutting line 15 at the upper end thereof becomes an opening 17 (see FIG. 3) that extends substantially horizontally. The opening 17 is opened to allow the flush water to flow to the outer peripheral surface of the neck of the container. In the skirt wall main portion 9 below the inward protruding portion 16, there is a thread forming region 18.
A coating layer 26 is applied to the inner surface of the top wall 5 of the cap body 2 (see FIG. 2).
The container 31 on which the metal cap 1 is covered is a metal container, and a curl portion 34 curved outward in the radial direction and having a substantially circular cross section is formed at the upper end of the mouth/neck portion 32. A jaw portion 33 whose lower side is curved inward in the radial direction is formed in the lower portion of, and the lower end portion of the tamper-evidence band 10 is locked to the jaw portion 33.

The liner 3 of the present embodiment has a two-layer structure including a barrier layer 20 located on the top wall 5 side and a sealing layer 21 formed on the surface of the barrier layer 20 opposite to the top wall 5. There is.
In this embodiment, the barrier layer 20 is formed of polypropylene as a main component, the sealing layer 21 is formed of an elastomer, and these two layers are integrally formed.
The shape of the barrier layer 20 is entirely circular according to the top wall 5, and is formed by a thin disk portion 22 on the center side and an outer peripheral projection 23 on the outer peripheral side. The outer peripheral projection 23 has an annular shape, and has a substantially arcuate cross-section along the inner surface shape of the liner holding portion 14 of the cap body 2, and the lower end portion is closer to the inner peripheral surface of the barrier layer 20. It projects downward. It is important that the outer diameter of the barrier layer 20 is smaller than the maximum outer diameter of the liner holding portion 14 and larger than the inner diameter of the holding projection 14a (see FIG. 4) below the liner holding portion 14.

The sealing layer 21 is molded on the lower surface of the barrier layer 20 and is formed integrally with the barrier layer 20. The outer diameter of the sealing layer 21 is smaller than that of the barrier layer 20, and is provided with an inner annular seal 24 located on the inner peripheral side of the mouth/neck portion 32 of the container 31 and an outer annular seal 25 located on the outer peripheral side thereof. The annular seals 24 and 25 project downward before the cap body 2 is tightened (see FIG. 3 ). Then, after the winding is fastened, the curling portion 34 is closely attached.
Regarding the liner 3 of the present invention, after the liner 3 shown in FIG. 3 is molded and before the cap body 2 is tightened, the liner 3 is arranged in a non-bonded state on the top wall 5. That is, after the liner 3 is molded and before the cap body 2 is attached to the mouth/neck portion 32 of the container 31, the liner 3 is not adhered to the top wall 5. (The specific manufacturing method will be described later.) The reason why the liner 3 becomes non-adhesive after molding is that the liner 3 is separated from the weak adhesive 27 due to contraction due to natural cooling, and is slightly separated from the liner holding portion 14. This is because a large gap is formed.

Therefore, the liner 3 is physically formed with the gap 28 with respect to the top surface wall 5 as described above, but after the liner 3 is molded, it is not adhered even in a contact state, and the outer peripheral projection 23 Is held by the liner holding portion 14, and the liner 3 is housed in the cap body 2. In a state where the cap body 2 is not attached to the mouth/neck portion 32 of the container 31, the liner 3 is rotatable relative to the top wall 5, and immediately after opening the cap, immediately after opening the cap. The main body 2 rotates relative to the liner 3 and does not rotate with respect to the mouth/neck portion 32 of the container 31. As the opening progresses, the liner 3 becomes free with respect to the cap body 2 and the mouth/neck portion 32, and the outer peripheral protrusion 23 of the liner 3 is lifted by the holding protrusion 14a and is separated from the mouth/neck portion 32.
In this way, the metal cap 1 can be opened without rotating the liner 3 with respect to the mouth/neck portion 32 having a large sealing force. Therefore, the sealing force of the liner 3 can be increased.

Next, a procedure for manufacturing the liner of the metal cap of the present invention will be described with reference to FIGS. The shape of the cap body 2 in FIGS. 4 to 6 is different from the shape of the cap body 2 after winding in FIG. 1 because the shape is before winding.
As the metal cap in this embodiment, various surface-treated steel plates and light metal plates such as aluminum can be preferably used, which are made of conventionally known metal materials. A resin-coated metal plate obtained by applying a coating agent to this metal material can also be used.
In the present embodiment, as shown in FIG. 2, a metal plate in which a coating layer 26 is applied to the inner surface of the metal plate at least at the site where the barrier layer 20 is formed, and a weak adhesive is further applied to the coating layer 26 is formed. The metal cap 1 shown in FIG. 4 was obtained by making it in advance and then punching and pressing it into a cap shape. Of course, the coating agent and the weak adhesive can be applied after the cap body 2 is molded. As the coating agent, a thermoplastic resin film containing epoxyphenol, polyester, polyesterphenolamide or the like as a main component can be used.
As the weak adhesive, solvents such as alkyd resin, petroleum hydrocarbon, and alkylbenzene can be used, and the adhesive component of polypropylene to these solvents is contained in an amount of 1 to 18% by weight, more preferably 1 to 10% by weight. It can be used. The particle size of the adhesive component is preferably 6 to 22 μm.

[Structure of Barrier Layer Mold]
Referring to FIG. 5, the first forming tool 41 for forming the barrier layer of the liner 3 includes a metal central punch 42, an intermediate pressing sleeve 43, and a peripheral sleeve 44, respectively. The cap body 2 is arranged with the top wall 5 facing downward. Further, the cap body 2 is preliminarily formed with the liner holding portion 14, the holding protrusion 14a, and the inward protruding portion 16.
The bottomed cylindrical center punch 42 is fitted to the inner peripheral surface 43 a of the intermediate pressing sleeve 43 so as to be relatively movable in the axial direction. The cylindrical intermediate pressing sleeve 43 is provided on the inner peripheral surface 44 a of the peripheral sleeve 44, and the cylindrical peripheral sleeve 44 is arranged so as to face the peripheral wall of the cap body 2. The intermediate pressing sleeve 43 is axially movable relative to the peripheral sleeve 44. The outer peripheral surface of the front end portion 44b of the peripheral sleeve 44 is formed into a tapered surface having a small diameter on the front end side, and is formed into a shape that abuts against the inner surface of the holding projection 14a (see FIG. 4) of the liner holding portion 14 without any gap. The tip surfaces of the central punch 42 and the sleeves 43, 44 are formed flat so as to be parallel to the inner surface of the top wall 5.

[Molding of barrier layer]
To form the barrier layer 20 of the liner 3, the weak adhesive 27 is applied on the surface of the coating layer 26 of the cap body 2.
The weak adhesive 27 plays a role of preventing the barrier material 46, which is a material of the barrier layer 20, from moving until it is pressed by the central punch 42, and a region to which the weak adhesive 27 is applied is shown in FIG. 5A. As described above, the area is R/2 or more in the radius R direction of the top wall from the center. This is determined from the area where the molten resin mass is dropped onto the inner surface of the cap body 2 before press molding. However, it is not necessary to apply it to the entire inner surface of the top wall 5. In this embodiment, the weak adhesive 27 is a alkyd resin solvent containing 1 to 10% of polypropylene adhesive component.

At the time of molding, the melted barrier material 46 is placed on the weak adhesive 27 aiming at the center of the top wall 5. The weak adhesive 27 has an adhesive force that can hold the barrier material 46 even when the cap body 2 is moving. It should be noted that the rolling prevention means may be used as long as the supplied barrier material 46 does not roll in the cap body that is being rotationally moved. For example, in addition to the weak adhesive, a friction material provided on the inner surface of the top wall of the cap body. Also, a locking means such as a minute protrusion may be used.
Then, the intermediate pressing sleeve 43 and the peripheral sleeve 44 are lowered so that the tip surfaces of these sleeves 43 and 44 form a gap with the top wall 5 by the thickness of the barrier layer 20. Next, the central punch 42 is lowered, and the barrier material 46 is compression molded. The barrier material 46 spreads outward in the radial direction as the central punch 42 descends, and when the central punch 42 descends to the same position as the sleeves 43, 44, the barrier material 46 becomes the liner holding portion 14 of the top wall 5. The disk portion 22 and the outer peripheral protrusion 23 of the barrier layer 20 are formed by wrapping around and filling up to the outer peripheral side of the peripheral sleeve 44. The outer peripheral surface of the outer peripheral protrusion 24 is formed along the inner peripheral surface of the liner holding portion 14. An annular vertical surface 20a that hangs from the disk portion 22 is formed on the inner peripheral side of the outer peripheral projection 23 (see FIG. 7).

At this time, the barrier material 46 is adhered to the inner surface of the top wall 5 with the weak adhesive 27 via the coating layer 26. The barrier material 46 adheres to the weak adhesive 27 although its adhesive strength is weak, but does not adhere to the coating layer 26. Therefore, the barrier layer 20 formed by the barrier material 46 is bonded to the top wall 5 at the portion where the weak adhesive 27 is present, but contacts the top wall 5 at the portion where the weak adhesive 27 is not applied. There is no adhesive connection.
When the molding of the barrier layer 20 is completed, the central punch 42, the intermediate pressing sleeve 43, and the peripheral sleeve 44 are lifted and separated from the cap body 2.

[Structure of molding die for sealing layer]
The second forming tool 51 for forming the sealing layer 21 of the liner 3 includes a metal central punch 52, an intermediate pressing sleeve 53, and a peripheral sleeve 54, respectively. The bottomed cylindrical center punch 52 is fitted to the inner peripheral surface 53a of the intermediate pressing sleeve 53 so as to be relatively movable in the axial direction. The cylindrical intermediate pressing sleeve 53 is provided on the inner peripheral surface 54 a of the peripheral sleeve 54, and the cylindrical peripheral sleeve 54 is also arranged facing the peripheral wall of the cap body 2. The intermediate pressing sleeve 53 is axially movable relative to the peripheral sleeve 54, and the shape of the tip portion 53 b thereof corresponds to form an inner surface between the inner and outer annular seals 24 and 25 of the sealing layer 21. It is formed in a shape. The peripheral sleeve 54 has an inner peripheral surface 54a fitted to the intermediate pressing sleeve 53 so as to be relatively movable in the axial direction, and the outer peripheral surface of the distal end portion 54b thereof is formed with a tapered surface having a small diameter on the distal end side. The liner holding portion 14 is formed in such a shape as to come into contact with the inner surface of the holding projection 14a (see FIG. 4) of the liner holding portion 14 without a gap.

[Molding of sealing layer]
To form the sealing layer 21 of the liner 3, the sealing material 47 is placed on the center of the surface of the barrier layer 20 formed on the top wall 5 of the cap body 2. The main component of the sealing material 47 is elastramer.
At the time of molding the sealing layer 21, the melted sealing material 47 is placed on the barrier layer 20 aiming at the center of the top wall 5. Then, the intermediate pressing sleeve 53 and the peripheral sleeve 54 are lowered. These sleeves 53 and 54 are lowered to the surface of the barrier layer 20, and the outer peripheral surface of the tip end portion 54b of the peripheral sleeve 54 is in contact with the inner circumference of the outer peripheral projection 23 of the barrier layer 20.

When the central punch 52 is lowered, the sealing material 47 spreads outward in the radial direction, and at this time, the intermediate pressing sleeve 53 is slightly raised to form a gap between the tip portion 54b and the barrier layer 20, and the peripheral sleeve 54. The sealing material 47 is filled up to the inner peripheral surface of. The disk portion 22 of the sealing layer 21 is formed on the side of the central punch 52, and the inner and outer annular seals 24, 25 are formed on the side of the intermediate pressing sleeve 53. Further, the outer annular seal 25 is formed with an annular vertical surface 21a that hangs from the outer peripheral portion of the sealing layer 21, and the vertical surface 21a is formed inside the vertical surface 20a of the barrier layer 20 with a space ( (See FIG. 7).
The barrier layer 20 and the sealing layer 21 are bonded together without an adhesive.
In this way, the liner 3 including the two layers of the barrier layer 20 and the sealing layer 21 is molded. When the molding of the sealing layer 21 is completed, the central punch 52, the intermediate pressing sleeve 53 and the peripheral sleeve 54 are lifted and separated from the cap body 2.

The liner 3 formed by continuous molding of the barrier layer 20 and the sealing layer 21 is maintained at a high temperature during molding, but the temperature is lowered by natural cooling in a room temperature (air) environment after molding. Polypropylene and elastomer have a property of shrinking by cooling, and the barrier layer 20 adhered to the inner surface of the top wall 5 through the coating layer 26 shrinks eventually.
Generally, at the time of molding, since the liner is continuously adhered to the top surface wall or the thin plate surface of the inside plug (see Patent Document 1) even after molding, the adhesive force is large. In this embodiment, the barrier layer 20 is adhered to the top wall 5 via the coating layer 26 during molding, and the weak adhesive 27 that separates the adhesive after molding is used. It goes to a limited extent.
That is, the coating layer 26 is made of a material that adheres to the adhesive but does not easily adhere to the polypropylene that forms the barrier layer 20, while the weak adhesive 27 is also made of a material having a weaker adhesive force than usual. I am using. When the liner 3 (particularly the barrier layer 20) contracts, the weak adhesive 27 peels from the barrier layer 20 against the adhesive force of the weak adhesive 27. Then, since there is no adhesive relationship between the liner 3 and the top wall 5 and the liner 3 is contracted, a physically small gap is formed between the top wall 5 and the liner holding portion 14 ( (See FIG. 7).

This gap allows the liner 3 to rotate in the circumferential direction relative to the cap body 2 and allows the cap body 2 to move slightly in the diametrical direction. Even after the liner 3 having such a gap is contracted, the outer diameter of the liner 3 is larger than the minimum inner diameter of the holding protrusion 14a of the liner holding portion 14. Therefore, in a natural (no-load) state, by forming the holding protrusion 14a, the outer peripheral portion of the liner 3 is locked by the holding protrusion 14a, and the liner 3 does not drop from the liner holding portion 14. ..

As described above, according to the present invention, the liner holding portion 14 is formed in advance when the cap body 2 is molded, and the cap body 2 and the liner 3 are separated by using the peelable adhesive when the liner 3 is molded. There is. Then, the liner 3 separated from the metal cap 2 can be held by the metal cap 2 only by a series of molding of the cap body 2 and the liner 3. Therefore, the setting step of inserting the liner into the metal cap is not required.

FIG. 3 shows a metal cap 1 including a cap body 2 and a liner 3 after molding and before winding. Therefore, at this point in time, the metal cap 1 has no screw formed in the screw forming region. In order to wrap the metal cap 1 around the mouth neck portion 32 of the container, the metal cap 1 is put on the mouth neck portion 32. In this state, the inner ring of the liner 3 is attached to the inner circumference of the upper end of the mouth neck portion 32. The seal 24 is provided, an outer annular seal 25 is provided on the outer periphery, and the mouth/neck portion 32 is located between the annular seals 24, 25.
In such a state, the tightening is performed. That is, while pressing the metal cap 1 covered on the mouth/neck part 32 against the upper end of the mouth/neck part 32 with a pressing tool (not shown), the shoulder part 13 is deformed by the pressing tool, and in this state, the cap By pressing a screw forming roller (not shown) against the skirt wall 6 of the main body 2 and rotating it along the screw of the mouth/neck portion 32, the screw forming area of the skirt wall 6 corresponds to the mouth/neck portion 32. To form the screw.
At the same time, the lower end of the tamper-evidence band 10 of the cap body 2 is deformed along the lower side of the jaw 33 by the tamper-evidence forming roller being pressed against the lower side of the mouth/neck portion 32.

In this way, as shown in FIG. 1, the metal cap 1 after tightening is wound, and the metal cap 1 seals the inside of the container 31.
As described above, the metal cap 1 after tightening the wire deforms the shoulder portion 13 of the metal cap 1 with the pressing tool, but when the shoulder portion 13 is deformed, the outer peripheral projection 23 of the liner 3 and the inner and outer annular seals are deformed. 24 and 25 are pressed against the mouth-neck portion 32, and by this winding, the outer peripheral protrusion 23 is deformed inward, the vertical surfaces 20a and 21a of the barrier layer 20 and the sealing layer 21 contact each other, and the outer annular seal 25 is The upper neck curl portion 34 of the mouth/neck portion 32 is pressed and deformed to seal the mouth/neck portion 32. On the other hand, the barrier layer 20 is pressed against the outer peripheral portion by the shoulder portion 13 of the cap main body 2 and is in a state of being pressed against it, so that relative rotation is impossible. However, as described above, they are not joined by adhesion.

Referring to FIG. 8, when the metal cap 1 is opened, by rotating it in the opening direction, the skirt wall 6 rises and is removed from the mouth/neck portion 32. At this time, Since the lower end of the tamper-evidence band 10 is engaged with the lower side of the jaw part 32, the rising of the tamper-evidence band 10 is restricted. And the metal cap 1 can be removed from the mouth/neck 32.
When the cap is opened, the metal cap 1 rotates relative to the mouth/neck portion 32, but the sealing layer 21 in contact with the mouth/neck portion 32 has the inner and outer annular seals 24 and 25 that are wound by tightening. The barrier layer 20 that is in close contact with the upper end of the mouth/neck portion 32 and is in contact with the inner surface side of the cap body 2 has a smaller frictional force than the close contact force between them, and as described above, is not adhered by an adhesive or the like. ..

Therefore, when the cap body 2 is opened, the liner 3 comes into close contact with the mouth/neck portion 32 side and relatively rotates with respect to the liner 3 on which the cap body 2 is stationary. The barrier layer 20 is made of polypropylene and has a small frictional force with respect to the cap body 2 made of metal such as aluminum. The liner 3 is prevented from rotating until the cap body 2 rotates. Then, the rise of the cap body 2 prevents the liner 3 and the cap body 2 from being rotated together until the adhesion between the liner 3 and the mouth/neck portion 32 is lost. In this way, since the barrier layer 20 and the top wall 5 are not adhered, even if the liner 3 increases the adhesion force (sealing property) of the mouth/neck portion 32, the influence on the opening force is reduced.
Even when the cap body 2 is lifted up, the liner 3 does not remain in the mouth/neck portion 32 because the outer peripheral projection 23 of the barrier layer 20 is held by the liner holding portion 14.

Next, a metal cap according to the second embodiment of the present invention will be described. The components having the same names as those in the first embodiment will be described with the same reference numerals.
In the first embodiment described above, the holding projections 14a at the bottom of the liner holding portion 14 hold the liner 3 and lift the liner when the cap is opened. As can be understood with reference to the metal cap 1 after tightening, when the shoulder portion of the metal cap 1 is formed, deformation occurs, so that the outer diameter of the liner 3 and the inner diameter of the holding protrusion 14a after contraction (maximum The difference with the small diameter part) may decrease. In other words, the engagement between the two may be weakened.
In the second embodiment of the present invention, when the holding protrusion 14a is less locked as described above, when the metal cap 1 is opened, the holding protrusion 14a does not sufficiently lift the liner 3. There is a fear. Even in such a case, a metal cap that can reliably lift the liner 3 is provided.

FIG. 9 is an enlarged cross-sectional view around the boundary between the top wall 5 and the skirt wall 6 of the metal cap 1. The metal cap 1 according to the present embodiment includes a cap body 2 and a liner 3. The cap body 2 has a circular top wall 5 and a cylindrical skirt wall 6 that hangs from the peripheral edge of the top wall 5.
The cap body 2 is different from the first embodiment in the form of the inward protruding portion 16. The inward protruding portion 16 will be described. The inward protruding portion 16 is formed by cutting lines 15 that are formed at intervals in the circumferential direction of the skirt wall 6. A plurality of tongue-shaped projecting portions are formed in the circumferential direction by projecting a region below the cutting line 15 inward in the radial direction, and the cutting line 15 at the upper end is substantially inwardly projecting portion 16. Becomes the tip portion 16a. The tip portion 16a is arranged at a position close to the lower portion of the liner holding portion 14.

Further, as shown in the sectional shape of FIG. 9, the inward protruding portion 16 extends obliquely upward from the base end side to the inner side in the radial direction of the cap body 2, and the tip end side extends vertically from the middle. The plurality of tip portions 16a of the inward protruding portion 16 are formed so as to protrude radially inward of the holding protrusion 14a. It is not necessary for all of the tip portions 16a of the inward protruding portions 16 to project inward from the holding projections 14a. For example, tip portions 16a located at every one or a plurality of projections project to the inside of the holding projections 14a. You may let me.

The liner 3 includes a barrier layer 20 on the top wall 5 side and a sealing layer 21 mounted on the surface of the barrier layer 20, and the materials of the barrier layer 20 and the sealing layer 21 are the same as those in the first embodiment. is there. The shape of the barrier layer 20 is the same as that of the above-described embodiment, and the barrier layer 20 is formed so as to be peeled off from the top wall 5 by contraction due to natural cooling, and the outer peripheral projection 23 thereof is held by the liner holding portion 14 of the cap body 2. To be done. Therefore, also in the second embodiment, after the liner 3 is molded and before the cap main body 2 is attached to the mouth/neck part 32 of the container 31, the liner 3 is not adhered to the top wall 5. is there. Regarding the shape of the sealing layer 21, in the present embodiment, the inner annular seal 24 is formed to be larger than the height of the outer annular seal 25, which is different from the first embodiment. The shape of the sealing layer 21 may be the same as that of the first embodiment.

As described above, the inward protruding portion 16 is opened to form the opening 17 for flowing the cleaning water on the outer peripheral surface of the container mouth/neck portion 32. However, in the present embodiment, the inward protruding portion 16 also has an auxiliary role of the liner holding portion. Fulfill
That is, the difference between the outer diameter of the liner 3 after contraction and the inner diameter (minimum diameter portion) of the holding projection 14a is reduced due to the deformation when forming the shoulder portion of the cap when winding the metal cap. Even in the case where the metal cap 1 is opened, the tip end 16a of the inward protruding portion 16 is located further inside than the minimum diameter portion of the holding protrusion 14a. Even if the lifting of 3 is insufficient, the tip end 16a of the inward protruding portion 16 reliably holds and lifts the liner 3, thus preventing the problem that the liner 3 remains at the mouth of the container 31.
As described above, according to the present embodiment, the liner 3 can be stably held with respect to the metal cap 1 at the time of opening the cap without coming off.

Next, a method of forming the liner 3 on the inner surface of the top wall 5 will be described.
In the first embodiment, as shown in FIG. 4, a cap body 2 having a cutting line 15 and an inward projection 16 is used. On the other hand, in the second embodiment, as shown in A of FIG. 10, a cap body 2 on which the cutting line 15 and the inward protruding portion 16 are not formed is used. Then, as shown in B of FIG. 10, the barrier layer 20 is formed. The method for forming the barrier layer 20 is the same as the procedure shown in FIG. The same applies to the case where a cap body to which a weak adhesive is applied in advance is used.

After forming the barrier layer 20, as shown in FIG. 10C, a cutting line 15 is formed by a cutter, and at the same time, a region below the cutting line 15 of the skirt wall is pushed inward in the radial direction to project inward. The part 16 is formed. The pushing amount is formed so that the position of the tip portion 16a of the inward protruding portion 16 is further inward than the minimum diameter portion of the holding protrusion 14a of the liner holding portion 14.
In the first embodiment, the barrier layer is formed after forming the cutting line and the inward protruding portion first. However, when the inward protruding portion 16 is formed first as in the first embodiment, the inward protruding portion 16 projects inward of the holding protrusion 14a, and therefore, when the peripheral sleeve 44 is lowered, The protrusion 16 and the peripheral sleeve 44 interfere with each other. Therefore, in the present embodiment, the cutting line 15 and the inward protruding portion 16 are formed after the barrier layer 20 is formed and before the sealing layer 21 is formed.

After the inward protruding portion 16 is formed, the sealing layer 21 is formed next. Referring to FIG. 10D, the second molding tool 51 for molding the sealing layer 21 of the liner 3 includes a central punch 52, an intermediate pressing sleeve 53, and a peripheral sleeve 54 from the inside to the outside.
Of these, the peripheral sleeve 54 is substantially different from the peripheral sleeve of the first embodiment, and in the first embodiment, the outer peripheral surface of the peripheral sleeve is brought into contact with the inner peripheral surface of the holding projection. However, the second embodiment is different in that the outer peripheral surface of the peripheral sleeve 54 is brought into contact with the inner side surface of the inward protruding portion 16.
That is, the lower end side outer peripheral surface 54c of the peripheral sleeve 54 is formed so as to abut the inner side surface of the inner protruding portion 16, and above that, it is slightly curved along the inner side surface shape of the inner protruding portion 16, Above the inward protruding portion 16, it is formed so as to extend along the inner surface of the skirt wall 6. Further, the tip end surface of the tip end portion 54b of the peripheral edge sleeve 54 is brought into contact with the surface of the barrier layer 20, and the tip end side inner peripheral surface 54a has a sealing material 47 (see FIG. 6) at the peripheral edge when the sealing layer 21 is formed. It functions as a weir so as not to leak to the outer peripheral side of the sleeve 54.
The tip surface of the intermediate pressing sleeve 53 is formed so as to correspond to the surface shapes of the inner annular seal 24 and the outer annular seal 25, and the central punch 52 defines the thickness of the central portion of the sealing layer 21. Thus, the barrier layer 20 and the sealing layer 21 are formed on the cap body 2.

FIG. 11 shows the test results of the opening force of the metal cap in the present embodiment at the time of first opening.
The vertical axis represents the initial opening torque (N·cm) after winding the metal cap, and the horizontal axis represents the weight% of the adhesive component of polypropylene to the alkyd resin solvent.
In the diagram, the triangles indicate that the liner cannot be peeled off while the liner is still attached to the cap body, and the circles indicate that the liner has peeled off from the cap body.
If the adhesive component of polypropylene is less than 1% by weight, the adhesive force is weak and the barrier material 46 cannot be temporarily locked (temporarily fixed) during molding. Further, when the adhesive component exceeds 18% by weight, the liner is not peeled off from the cap body, and the initial opening torque becomes extremely high. When the content of the adhesive component is in the range of 1% by weight or more and 10% by weight or less, the liner is surely peeled off to show an appropriate initial opening torque, and this range is most preferable.

As described above, according to the present embodiment, it is possible to produce at a lower cost as compared with the case where the liner is formed on the thin metal plate, and the cap body is opened compared to the case where the liner is adhered to the cap body. The torque can be reduced. Further, the liner 3 according to the present embodiment has a two-layer structure of polypropylene and elastomer, but since the elastomer having a sealing force larger than that of polypropylene is used for the sealing portion, the sealing property can be improved.

The present invention has been described above in detail based on the embodiments with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and other modifications can be made without departing from the scope of the present invention. Alternatively, it can be changed.
In the second embodiment, the process of forming the inward protruding portion 16 is described in the order including the process between the process of forming the barrier layer 20 and the sealing layer 21, but, for example, After forming the barrier layer 20 and the sealing layer 21, the inward protruding portion 16 may be further molded. The cutting line 15 is formed along with the molding of the inward projecting portion 16 when the molding of the inward projecting portion 16 is simultaneously performed by pressing, but the barrier layer 20 is formed only when it is not simultaneously formed. It may be formed in advance before performing.
Furthermore, in the first embodiment, the barrier layer 20 is formed after the inward protruding portion 16 is formed. However, as in the second embodiment, the step of forming the inward protruding portion is the barrier. It may be performed between the step of molding the layer and the step of molding the sealing layer, and the step of forming the inward protrusion may be performed after the step of molding the sealing layer.
Further, regarding the material of the coating agent, the material of the weak adhesive, the material of the barrier layer, and the material of the adhesion sheet, the examples given in the above embodiment are only examples thereof, and are not limited to these. ..
In the above embodiment, the weak adhesive is attached to the coating layer side, but it may be attached to the barrier layer side.

DESCRIPTION OF SYMBOLS 1 Metal cap 2 Cap body 3 Liner 5 Top wall 6 Skirt wall 13 Shoulder part 14 Liner holding part 14a Holding protrusion 15 Cutting line 16 Inner protrusion 20 Barrier layer 21 Sealing layer 23 Outer peripheral protrusion 24 Inner ring seal 25 Outer ring Seal 26 Coating layer 27 Weak adhesive 31 Container 32 Mouth and neck 33 Jaw 46 Barrier material 47 Sealant

Claims (5)

A cap main body having a circular top wall and a cylindrical skirt wall hanging from a peripheral edge of the top wall; and a synthetic resin liner disposed on an inner surface of the top wall,
In a metal cap with a liner, wherein the skirt wall is formed with a liner holding portion which projects radially outward and holds an edge portion of the liner,
The liner includes a barrier layer on the top surface wall side and an inner sealing layer of the metal cap formed by supplying a liner-forming molten resin into the cap body and then press-molding the molten resin. The two-layer structure of
A coating layer is formed on the inner surface of the cap body to make the inner surface and the barrier layer non-adhesive, and a molten barrier resin at the time of molding the barrier layer is temporarily formed on the surface of the coating layer. Provided with a molten resin rolling prevention means that is locked to the top wall,
The metal cap, wherein the liner is not adhered to the top wall after the liner is molded and before the cap body is attached to the mouth and neck of the container. The metal cap according to claim 1, wherein the rolling prevention means is formed in a central portion of an inner surface of the ceiling wall. The metal cap according to claim 1 or 2, wherein the rolling prevention means is a weak adhesive capable of peeling from the barrier layer. The metal cap according to claim 1, wherein the barrier layer is made of polypropylene, and the sealing layer is made of elastramer. At the lower end of the liner holding portion, a holding protrusion that protrudes inward of the skirt wall and holds the liner on the inner peripheral surface is formed.
The metal cap according to any one of claims 1 to 4, wherein an inward protruding portion is formed below the holding protrusion so as to protrude radially inward of the cap body with respect to the holding protrusion.