JP2020132262A - Can lid and can therewith - Google Patents

Abstract

To provide a can lid and a can therewith with an enhanced steam barrier property and an improved sealing property.SOLUTION: A can lid is provided with: a lid body having an opening part; a covering seal member covering the opening part and bonded on a surface of the lid body; and a rear surface covering body bonded on a rear surface of the lid body and a rear surface of the covering seal member to cover the opening part over a rear surface side, wherein the rear surface of the covering body is formed by a laminated body made of a plurality of layers, at least one layer of which is a steam barrier layer, the steam barrier layer being an aluminum foil layer and being bonded on the lid body through a bond layer.SELECTED DRAWING: Figure 3

Description

The present invention relates to a can lid for sealing a can filled with food, beverage, etc. and a can provided with the lid.

Generally, a can filled with a beverage or the like is composed of a can body and a can lid that closes the opening end of the can body, and a metal tab makes it easy to open an opening that is a drinking port in the can lid. Open cans are known. Easy-open cans using this metal tab require complicated processing of the top plate and tabs of the can lid. In addition, the shape of the spout is restricted because the portion to be the spout is pushed in to open the package. On the other hand, a can using a can lid to which a sealing material is adhered so as to cover the opening of the can lid is also known. The can lid using this sealing material does not require complicated metal processing, and can be easily opened by peeling off the sealing material.

For example, Patent Document 1 includes a can body and a can lid attached to the can body by winding, and a drinking port is formed on the top plate of the can lid and is used to cover the drinking port. A can in which a lid material having a base material and a sealant is bonded by heat sealing has been proposed.
Further, Patent Document 2 proposes a can lid including a lid frame body having an opening formed and a film-shaped top surface sealing material that covers the opening and closes the opening freely.
Further, in Patent Document 3, the opening of the panel portion is a container lid sealed by a sealing member, and the sealing member covers the sheet material attached to the outer surface of the panel portion and the cut end of the opening. At the same time, a container lid made of a resin-coated member attached to a sheet material has been proposed. In this case, the sheet material has a resin coating formed on both sides of a metal foil such as an aluminum foil, and this sheet material is arranged on the outer surface side of the panel portion, and the resin coating material hides the cut end of the opening of the panel portion. It is adhered to the inner surface of the sheet material in the state.

Japanese Unexamined Patent Publication No. 9-239473 Japanese Unexamined Patent Publication No. 2008-137711 Japanese Unexamined Patent Publication No. 2014-181555

However, in any of the techniques shown in the patent documents, the water vapor barrier property is insufficient, and when a liquid such as juice is filled, water vapor permeates the seal portion from the back surface side to reduce the adhesion, resulting in long-term storage. In that case, the contents may be leaked. In particular, in beverages such as carbonated beverages on which internal pressure acts, leakage from the sealed portion becomes faster.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a can lid having improved water vapor barrier property and improved sealing property, and a can provided with the same.

The can lid of the present invention has a lid body having an opening, a covering seal member that covers the opening and is adhered to the surface of the lid body, and a back surface of the lid body and a back surface of the covering sealing member. It is provided with a back surface side covering body that is adhered and covers the opening on the back surface side, and the back surface side coating body is composed of a laminated body of a plurality of layers, and at least one layer thereof is a water vapor barrier layer.

In this can lid, since the water vapor barrier layer is provided on the back surface side coating that is adhered to the back surface of the lid body, the water vapor barrier layer prevents water vapor (moisture) from the contents from permeating into the seal portion. It is possible to improve the adhesion of the coating seal member and prevent the occurrence of leakage even during long-term storage.

In one embodiment of the can lid, the water vapor barrier layer may be an aluminum foil layer and may be adhered to the lid body via an adhesive layer.
The water vapor barrier layer can be easily formed by the aluminum foil layer, and the barrier property can be surely exhibited. Appropriate openability can be obtained by combining the aluminum foil layer and the adhesive layer.

In this can lid, the thickness of the aluminum foil layer is preferably 10 μm or more and 40 μm or less.
If the thickness of the aluminum foil layer is less than 10 μm, tears or holes may occur during manufacturing, and if the thickness exceeds 40 μm, the aluminum foil layer may not be cut at the time of opening and may remain in the opening.

The can of the present invention includes a can body portion and the can lid attached by closing the open end of the can body portion.
Since this can is provided with a can lid attached by closing the opening end of the can body, it is possible to prevent the contents from leaking from the opening and to easily open the can.

According to the present invention, the water vapor barrier layer can prevent water vapor (moisture) from the contents from permeating into the seal portion, improve the adhesion of the coating seal member, and prevent the occurrence of leakage even during long-term storage. can do.

It is a vertical sectional view which shows the can lid of 1st Embodiment of this invention. It is a top view of FIG. It is an enlarged sectional view of the main part of FIG. It is a vertical cross-sectional view which omitted the lower part of the can body which shows the state which the can lid of FIG. 1 was wound around the can body. It is a top view which shows the can lid of the 2nd Embodiment of this invention. It is a top view which shows the can lid of the 3rd Embodiment of this invention. It is a top view which shows the can lid of 4th Embodiment of this invention.

Hereinafter, embodiments of a can lid and a can provided with the can lid according to the present invention will be described with reference to the drawings.

The can lid 1 of the first embodiment is a can lid that closes an opening end of a beverage can or the like, and as shown in FIGS. 1 to 3, a lid body 2 having an opening 2a and an opening 2a. The covering seal member 3 which covers and is adhered to the front surface of the lid main body 2, and the back surface side covering member 4 which is adhered to the back surface of the lid main body 2 and the back surface of the covering sealing member 3 and covers the opening 2a on the back surface side. And have.

The lid body 2 has a metal plate portion 5 made of aluminum or an aluminum alloy or the like, and an outer surface coating film formed of an epoxy-based, acrylic-based, vinyl chloride-based, PP compound, PE compound or the like on the surface (outer surface) of the metal plate portion 5. An opening composed of 5a and an inner coating film 5b formed of an epoxy-based, acrylic-based, vinyl chloride-based, PP compound, PE compound, etc. on the back surface (inner surface) of the metal plate portion 5, and which becomes a drinking spout by press working. 2a, an outer peripheral portion 2b wound around the can body portion 11, a counter sink portion 2c arranged inside the outer peripheral portion 2b, a panel portion 2d inside the counter sink portion 2c, and the like are molded.
In the example shown in FIG. 2, the opening 2a is formed in the panel portion 2d along the radial direction from the vicinity of the central portion toward the outer peripheral portion, and the outer peripheral portion side is wider than the central portion side of the panel portion 2d. It is formed in a triangular shape.

The coating seal member 3 includes an aluminum foil layer 3a for maintaining barrier properties, a protective layer 3b formed on one surface of the aluminum foil layer 3a, and an adhesive layer 3c formed on the other surface of the aluminum foil layer 3a. A laminating material composed of and is used.
The aluminum foil layer 3a is made of pure aluminum or an aluminum alloy, and for example, JIS 8021 material and 1N30 material are used, and the thickness is 20 μm or more and 100 μm or less.
The protective layer 3b has a function of protecting the aluminum foil layer 3a, and a film made of a resin such as polypropylene or polyester is used. Polyethylene terephthalate (PET) is suitable.
The adhesive layer 3c is made of a hot melt resin having a heat-sealing property with the outer surface coating film 5a of the lid body 2, and a film such as polypropylene, polyethylene, or ethylene vinyl acetate (EVA) resin is used. An intermediate layer made of polyethylene terephthalate (PET) or a sealant may be formed between the aluminum foil layer 3a and the adhesive layer 3c.
The covering seal member 3 has a knob portion 3d that protrudes outward in the radial direction from the panel portion 2d to the outer peripheral side of the can lid 2 when the opening 2a of the can lid 2 is covered. The knob portion 3d may be provided so as to be arranged on the central portion side of the can lid 2.

As the back surface side covering body 4, a laminated material composed of an aluminum foil layer 4a and an adhesive layer 4b formed on one surface of the aluminum foil layer 4a is used.
The aluminum foil layer 4a is made of pure aluminum or an aluminum alloy, and for example, JIS 8021 material and 1N30 material are used, and the thickness is 10 μm or more and 40 μm or less.
The adhesive layer 4b is made of a hot melt resin having a heat-sealing property with the inner surface coating film 5b of the lid body 2, and a film such as polypropylene, polyethylene, or ethylene vinyl acetate (EVA) resin is used.
As the adhesive layers 3c and 4b of the coating seal member 3 and the back surface side covering body 4, a combination of materials in which the adhesive force between them is larger than the shearing force of the back surface side covering body 4 is selected. To.

Further, as shown in FIG. 4, the can 10 of the present embodiment includes a can body 11 and the can lid 1 mounted by closing the open end of the can body 11.
The can body 11 is made of, for example, aluminum. At the open end of the can body 11, the outer peripheral portion 2b of the can lid 1 is wound and the winding tightening portion 10a is formed. The front surface of the can lid 1 is an outer surface when attached to the can 10, and the back surface is an inner surface.

Next, a method for manufacturing the can lid 1 of the present embodiment will be described.
Regarding the lid body 2, after forming the outer surface coating film 5a and the inner surface coating film 5b on the aluminum coil material, the lid body 2 is pressed to form an opening 2a for putting out the contents at a predetermined portion and a can body portion 11. It is formed in a shape having an outer peripheral portion 2b to be wound.

The coating seal member 3 is formed by punching a laminated material in which an aluminum foil layer 3a, a protective layer 3b, and an adhesive layer 3c are laminated into a predetermined shape.
The back surface side covering body 4 is formed by punching a laminated material in which an adhesive layer 4b is laminated on an aluminum foil layer 4a into a predetermined shape.
The coating seal member 3 is arranged so that the adhesive layer 3c is overlapped with the outer surface of the lid main body 2, and is adhered by heat-sealing with the opening 2a closed. This heat sealing step also includes a method using high frequency or ultrasonic sealing.
The back surface side covering body 4 is also arranged so that the adhesive layer 4b is overlapped with the inner surface of the lid main body 2, and is adhered by heat-sealing the opening 2a in a closed state. At this time, the back surface side covering body 4 is adhered to both the back surface of the lid main body 2 and the back surface of the covering seal member 3 exposed to the opening 2a around the opening 2a. This heat sealing step also includes a method using high frequency or ultrasonic sealing.
The covering seal member 3 and the back surface side covering body 4 can be arranged so as to sandwich the lid main body 2 and heat-sealed at the same time.

In the can lid 1 configured in this way, the covering seal member 3 is arranged on the front surface side of the opening 2a, and the back surface side covering body 4 is arranged on the back surface side, and the opening 2a is formed by the covering sealing member 3 and the back surface side covering body 5. It is sealed so as to sandwich it. Since the coating seal member 3 and the back surface side covering body 5 have aluminum foil layers 3a and 4a, they are excellent in water vapor barrier property, and in particular, the aluminum foil layer 4a of the back surface side covering body 5 opens from the back surface side. Since it covers the inner peripheral edge of the portion 2a, it is possible to reliably prevent water vapor (moisture) from the contents from permeating into the seal portion, the adhesion of the covering seal member 3 is maintained, and leakage occurs even during long-term storage. Can be prevented from occurring. In this case, since the aluminum foil 4a of the back surface covering body 4 is formed to have a thickness of 10 μm or more, it has a sufficient water vapor barrier property. If the thickness is less than 10 μm, tears or holes may occur during manufacturing. There is.

Further, since the opening 2a is closed by the covering seal member 3 and the back surface side covering body 4, when applied to the can 10, sufficient adhesive force can be obtained without setting a wide adhesive area of the covering sealing member 3. It is possible to prevent leakage of the contents even when the obtained product is subjected to high temperature or high pressure such as sterilization treatment.
In the state before the opening, the inner peripheral edge of the metal plate portion 5 in the opening 2a is covered with the adhesive layers 3c and 4b of the covering seal member 3 and the back surface side covering body 4, and the metal plate portion 5 is exposed. It is not and corrosion is prevented.
That is, when unopened, the inner peripheral edge portion of the metal plate portion 5 can be protected from contact with liquid. Moreover, the inner peripheral edge portion of the opening 2a is firmly protected by both the coating seal member 3 and the back surface side covering body 4, and corrosion can be reliably prevented.

On the other hand, when opening the package, the covering seal member 3 and the back surface side covering body 4 in the opening 2a are separated from the lid main body 2 by pulling by holding the knob portion 3d of the covering sealing member 3 to open the opening 2a. It can be opened. In this case, the coating seal member 3 is peeled off between the adhesive layer 3c and the lid body 2. On the other hand, in the back surface side covering body 4 adhered to the back surface of the coating seal member 3, the adhesive force between the adhesive layers 3c and 4b of the coating sealing member 3 and the back surface side covering body 4 is stronger than that of the back surface side covering body. Since it is larger than the shearing force of 4, the inner portion of the opening 2a of the lid body 2 is pulled by the covering seal member 3, and the back surface side covering 4 is sheared at the inner peripheral edge of the opening 2a, whereby the covering sealing member The inner portion of the opening 2a is divided while being adhered to the back surface of the third, and is peeled off together with the covering seal member 3, so that the opening 2a can be opened. The portion of the back surface side covering 4 that has been adhered to the outer peripheral portion of the opening 2a remains adhered to the lid body 2.
In this case, since the aluminum layer of the back surface side covering is formed to have a thickness of 40 μm or less, it is surely sheared at the time of opening. If the thickness exceeds 40 μm, the aluminum foil 4a may not be cut and remains inside the opening 2a at the time of opening.

As described above, in the can 10 provided with the can lid 1 of the present embodiment, the contents can be prevented from leaking from the opening 2a and can be easily opened. Therefore, the can 10 of the present embodiment has a pressure resistance that can withstand a case of being filled with a carbonated beverage or a case of being retort-treated, and is suitable for a so-called positive pressure can.

The present invention is not limited to each of the above embodiments, and various modifications can be made without departing from the spirit of the present invention.
A thin protective layer may be formed on the surface of the aluminum foil layer of the back surface side coating as long as the breakage of the back surface side coating during opening is not impaired. When this protective layer is provided, a cut groove (so-called half-cut) that cuts from the protective layer to the middle of the thickness of the aluminum foil layer may be formed in a shape along the inner peripheral edge of the opening 2a.

The shape of the opening 2a is also one having a large number of holes like the can lid 21 of the second embodiment shown in FIG. 5, and a plurality of holes having different shapes like the can lid 31 of the third embodiment shown in FIG. It may be made of, and various settings can be made such as not only a circular hole but also a square hole like the can lid 41 of the fourth embodiment shown in FIG. 4, and the covering seal member 3 The outer shape can also be appropriately changed according to the shape of the opening 2a. In these figures, the components common to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
Further, printing may be performed on the covering seal member 3. The printing can be performed either before or after adhering to the lid main body 2.

As the lid body, an epoxy-based coating film was formed on both sides of an aluminum metal plate portion, and a circular opening having a diameter of 10.5 mm was formed in the central portion.

As the covering seal member, the following three types (1) to (3) were produced. The laminated structure is shown in the order of the adhesive layer, the intermediate layer, the aluminum foil layer, and the protective layer, respectively, and the thickness is described after each layer. "PET" indicates polyethylene terephthalate, and "AL" indicates aluminum foil. As the intermediate layer, a single layer of polyethylene terephthalate and a two-layer structure of polyethylene terephthalate and a sealant were used. For the adhesive layer, Herodine 7589 from the Herodine 7000 series manufactured by Yasuhara Chemical Co., Ltd. was used.

(Layer structure of covering seal member)
(1): Adhesive layer 20 μm / PET layer 12 μm / AL layer 20 μm / PET layer 12 μm
(2): Adhesive layer 20 μm / Sealant layer 50 μm / PET layer 12 μm / AL layer 20 μm / PET layer 12 μm
(3): Adhesive layer 20 μm / Sealant layer 50 μm / PET layer 12 μm / AL layer 57 μm / PET layer 12 μm

The back surface side covering has a two-layer structure of an adhesive layer and an aluminum foil layer, a two-layer structure of an adhesive layer and polyethylene terephthalate, and three types of laminated structures of only an adhesive layer. From the Herodine 7000 series manufactured by Yasuhara Chemical Co., Ltd., the following three types, X to Z, were used.
X: Herodine 7589
Y: Herodine 7574
Z: Herodine 7560
The layer structure of the back surface side covering was as shown in Table 1. In the table, those marked with / are a two-layer structure consisting of an adhesive layer and an aluminum foil (AL) layer or a polyethylene terephthalate (PET) layer. The thickness of each layer is shown.

A covering seal member and a back surface side covering body were arranged on both sides of the opening of the lid body, and pressure was applied from the covering sealing member side to heat seal. At that time, the mold temperature was 230 ° C., the heat seal time was 1.6 seconds, and the heat seal pressure was 3.0 kg / cm ² .
After the can lid was wrapped around a can body filled with a carbonated beverage, it was left at room temperature (25 ° C.) to investigate the number of days until a leak occurred. The internal pressure immediately after filling was 600 kPa on average. For the occurrence of leakage, the degree of swelling of the covering seal member was visually confirmed. It was judged that a leak occurred when the covering seal member had no bulge. The number of days until the leak occurred was designated as A, and the number of days until the leak occurred was less than 30 days as B.
Further, after the can lid was wrapped around the can body filled with the carbonated beverage, the peel strength when the coating seal member was pulled to open the opening was measured. The peel strength after holding the can filled with the carbonated beverage in a high temperature and high humidity environment at a temperature of 120 ° C. and a humidity of 100% for 30 minutes was also measured, and the rate of change with respect to the initial peel strength was calculated. The peel strength was measured using a universal testing machine under the conditions of a peeling angle of 90 ° and a peeling speed of 200 mm / min. The peel strength after holding in a high temperature and high humidity environment was designated as A when the peel strength was 75% or more with respect to the initial peel strength, and B when the peel strength was less than 75%.
These results are shown in Table 1.

As shown in Table 1, in the configuration provided with the water vapor barrier layer made of aluminum foil, both the leakage and peel strength are evaluated as A, and in the configuration without the water vapor barrier layer, both the leakage and peel strength are evaluated as B. It was.

1, 21, 31, 41 Can lid 2 Lid body 2a Opening 3 Coating seal member 3a Aluminum foil layer 3b Protective layer 3c Adhesive layer 4 Back side covering 4a Aluminum foil layer 4b Adhesive layer 10 Can 11 Can body

Claims (4)

The lid body having an opening, the covering seal member covering the opening and adhering to the surface of the lid body, and the back surface of the lid body and the back surface of the covering sealing member are adhered to the opening. A can lid comprising a back surface side covering body covering the back surface side, the back surface side coating body is composed of a laminate of a plurality of layers, and at least one layer thereof is a water vapor barrier layer. The can lid according to claim 1, wherein the water vapor barrier layer is an aluminum foil layer and is adhered to the lid body via an adhesive layer. The can lid according to claim 2, wherein the thickness of the aluminum foil layer is 10 μm or more and 40 μm or less. A can comprising a can body and a can lid according to any one of claims 1 to 3, which is attached by closing the open end of the can body.

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