JP5142512B2 - Can lid - Google Patents

Description

  The present invention relates to a can lid that is suitably used for a container that is opened by peeling a top surface sealing material.

  2. Description of the Related Art Conventionally, a can lid having a film-like top surface sealing material whose outer periphery is wound around a can container and that releasably seals an opening formed in a panel portion is known (see, for example, Patent Document 1). . Since only the outer periphery of the top surface sealing material is bonded along the opening, it can be opened simply by peeling the top surface sealing material by using it in a can container containing food. Can be easily performed. Moreover, even if the shape of the opening is formed in a desired shape, the can container can be easily and surely sealed with the top seal material. In particular, this type of can lid can be provided with a relatively large opening according to the contents, so that it can be used not only for solid foods and semi-solid foods but also for beverages containing solids. The contents can be easily removed. Moreover, by providing a large opening, the inside of the can can be easily cleaned even after the contents are taken out, and thus there is an advantage that the recycling process is facilitated.

  However, when a relatively large opening is provided in this type of can lid, the shape of the top seal material for covering the entire opening is also increased. And since the top sealing material is in the form of a film, it tends to bend and extend, and when a relatively large opening is sealed, the amount of bending and extension of the portion covering the opening becomes large. For this reason, when the so-called retort treatment for heat sterilizing the food as the contents is performed, the top seal material expands outward due to an increase in the internal pressure of the can container due to heating. Then, when the internal pressure of the can container is lowered by cooling thereafter, the extended top sealing material is loosened, so that the outer periphery of the top sealing material along the opening is wrinkled and the appearance is crumpled, or cracks or There is an inconvenience that partial peeling occurs and sealability cannot be obtained.

In addition, this type of can lid is thought to be formed with sharp edges at the edges of the panel because the panel is made of metal, and due to a decrease in the internal pressure of the can during cooling after retorting. If the top seal is pulled toward the inside of the can, the top seal will be pressed against the edge of the opening and the top seal may be damaged, which may prevent the seal from being maintained by the top seal. is there. In addition, if the edge of the opening is exposed to the inside of the can container, corrosion may occur on the edge of the opening due to the influence of the contents.
Japanese Patent Laying-Open No. 2005-154015 (FIG. 4)

  By eliminating such inconvenience, the present invention can prevent the occurrence of wrinkles in the top surface sealing material to obtain a good appearance and maintain high sealing performance, and can reliably prevent corrosion, An object of the present invention is to provide a can lid that can be suitably used for a can container whose internal pressure changes in retort processing or the like.

In order to achieve the above object, the present invention provides a metal lid having a winding portion for winding on a can container at an outer peripheral edge portion and having an opening formed in a panel portion surrounded by the outer peripheral edge portion. A can lid comprising a frame and a film-like top surface sealing material that covers the opening from the upper surface side and closes the opening freely, wherein the inner peripheral edge of the opening is on the upper surface side of the panel portion A folded portion having a plurality of folded ends and housed inside with the edge thereof being unexposed, is provided on the entire periphery of the opening portion, and the top surface sealing material is disposed on the panel portion excluding the folded portion. Adhering along the circumference, and being recessed and provided in the opening from the inner peripheral edge of the folded portion toward the inside of the can container, it is possible to bulge upward as the internal pressure of the can container increases. The opening portion is allowed to be sealed in an airtight state.

According to the present invention, the folded portion is formed by folding a plurality of folded portions on the upper surface side of the panel portion, and the inner peripheral edge of the opening is accommodated in the folded portion. There is no adhesion of the contents to the peripheral edge, and corrosion at the inner peripheral edge of the opening can be reliably prevented. In addition, since the top surface sealing material is adhered on the panel portion excluding the folded portion, for example, when the can lid of the present invention is attached to the can container and the retort treatment is performed, the ceiling pressure is increased by the increase in the internal pressure of the can container. Even if the face seal material bulges outward and is pulled to the inside of the can container due to a decrease in internal pressure, the top face seal material comes into contact with the folded portion and resists the pulling, and the adhesive part of the top face seal material The generation of wrinkles along the line can be suppressed.
In addition, since the top surface sealing material is recessed into the opening from the inner periphery of the folded portion toward the inside of the can container, the amount of bending of the top surface sealing material accompanying the change in the internal pressure of the can container can be reduced. It can be made relatively large, and the generation of wrinkles can be prevented by suppressing the extension of the top sealing material. And since the tension | tensile_strength provided to the adhesion part of a top | upper surface sealing material and a panel part can be weakened and an adhesion state can be maintained reliably, high sealing performance can be acquired.

  Moreover, in the can lid of this invention, the upper end surface of the said folding | turning part and the upper surface of the said panel part are located on the same straight line in sectional view, It is characterized by the above-mentioned. According to this, the top surface sealing material bonded to the panel portion can be flatly adhered to the upper end surface of the folded portion, and the intrusion of contents between the folded portion and the top surface sealing material can be suppressed. Can do. Moreover, the wrinkles at the bonding portion between the top surface sealing material and the panel portion are also stretched flat, and a good appearance can be obtained.

  Further, in the can lid of the present invention, the panel portion and the folded portion are provided to be inclined outwardly of the can container toward the center of the opening portion with the outer periphery of the panel portion as a base end. Features. According to this, when the top sealing material bulges outward due to an increase in the internal pressure of the can container, the panel portion and the folded portion substantially coincide with the bulging direction of the top sealing material. The amount of output can be made small. In addition, even if tension is applied to the bonding part to the panel part when the top seal material swells, the panel part that becomes the bonding part is inclined so that the tension is applied in the surface direction intersecting the peeling direction of the bonding part. Since it is provided, it is possible to reliably maintain the adhesive state between the top surface sealing material and the panel portion, and to obtain high sealing performance.

  In the can lid of the present invention, the folded portion is formed by folding a first bent portion formed by folding an end edge on the upper surface side of the panel portion, and folding the first bent portion on the upper surface side of the panel portion. A second bent portion and a third bent portion in which the second bent portion is folded back to the upper surface side of the panel portion and the first bent portion is wound inside. It is preferable that the edges are sealed to each other and sealed inside the folded portion. Thereby, even if the contents of the can container enter between the folded part and the top seal material, the contents are prevented from entering the folded part. In addition, since the first to third bent portions are provided and the upper surface of the panel portion and the bent portions are in close contact with each other, for example, the contents of the can container between the folded portion and the top seal material Even if the internal pressure of the can container rises during retort processing when an object has infiltrated, the contents are firmly prevented from entering the folded part, and corrosion of the inner peripheral edge of the opening is ensured. Can be prevented.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a can lid of a form in which the present invention is not adopted , FIG. 2 is an explanatory view showing a part of the can lid of FIG. 1 broken away, and FIG. 3 is a partially enlarged view showing a panel portion and a folded portion. FIG. 4, FIG. 4 is an explanatory view showing the action of the top surface sealing material, FIG. 5 is an explanatory view showing the top surface sealing material according to the embodiment of the present invention , and FIG. 6 is another can lid in which the present invention is not adopted. panel section and a partially enlarged view showing a folded portion, FIG. 7 is an explanatory diagram showing the action of the top sealing member in FIG. 6 shows the form, Figure 8 is top sealing material employing the present invention in FIG. 6 shows the can lid It is explanatory drawing which shows .

As shown in FIG. 1, the can lid 1 includes a metal lid frame 2 and a top sealing material 3 for opening provided on the lid frame 2 so as to be peelable. Top sealing material 3, Thickness polypropylene film having a thickness of about 30μ aluminum foil 45~80μ on its inner surface as a substrate is bonded, polyethylene terephthalate film is adhered with a thickness of about 12μ on the outer surface side of the substrate What has been adopted is adopted.

  The lid frame 2 is stamped and formed from a metal plate material such as steel, and as shown in FIG. 2, a tightening portion 4 for tightening the can container X, and a panel extending inwardly from the tightening portion 4 A portion 5 and a circular opening 6 formed in the panel portion 5. Further, a folded portion 7 is formed at the peripheral edge of the opening 6.

  In addition, a coating film is applied to the upper surface (outer surface) of the lid frame 2 from the outer peripheral edge of the tightening portion 4 to the inner peripheral end of the opening 6. The coating film is, for example, baked and cured at 190 ° C. for 10 minutes after applying an epoxy phenol paint, and further baked and cured at 180 ° C. for 10 minutes after applying a polypropylene dispersed epoxy phenol paint on the upper layer. It is formed by. In addition, although a coating film is provided also in the lower surface (inner surface) of the lid frame 2, the coating material is suitably determined according to the content.

  On the upper surface of the panel portion 5 excluding the folded portion 7, that is, on the upper surface of the panel portion 5 between the winding fastening portion 4 and the folded portion 7, the peripheral portion of the top surface sealing material 3 can be peeled off to the coating film by heating. As a result, the entire circumference of the top surface sealing material 3 is adhered, and the opening 6 is closed. In addition, the top | upper surface sealing material 3 is adhere | attached on the cover frame body 2 upper surface by high frequency heating, for example.

  The top surface sealing material 3 is composed of a strip opening tab 8 extending outwardly from a part of the periphery thereof and a closing portion 9 covering and closing the opening 6, as shown in FIG. The peripheral portion is provided with an adhesive portion 10 adhered to the upper surface of the panel portion 5. A contact portion 11 that contacts the upper surface of the folded portion 7 is provided on the entire circumference between the adhesive portion 10 and the closing portion 9. As shown in FIGS. 1 and 2, the tab 8 is provided to be folded back on the upper surface side of the closing portion 9. Thereby, the size of the tab 8 can be formed to be relatively large, and can be easily grasped at the time of the opening operation without being obstructed during the operation such as winding.

  Further, as shown in FIG. 2, the folded portion 7 is formed by folding a plurality of end edges 12 on the entire circumference of the opening 6 on the upper surface side of the panel portion 5. More specifically, as shown in FIG. 3, the folded portion 7 includes a first bent portion 13 formed by folding an end edge 12 on the upper surface side of the panel portion 5, and the first bent portion 13 is connected to the panel portion 5. The second bent portion 14 is formed by folding back to the upper surface side, and the third bent portion 15 is formed by folding the second bent portion 14 to the upper surface side of the panel portion 5 and winding the first bent portion 13 inside. The upper surface of the panel portion 5 and the bent portions 13, 14, 15 are formed in close contact with each other. Further, the upper end surface of the folded portion 7 and the upper surface of the panel portion 5 are located on the same straight line in a cross-sectional view and are formed flat. In this way, a plurality of folded portions 7 are folded back on the upper surface side of the panel portion 5, and the edge 12 is housed inside the folded portion 7 in an unexposed state, and is in close contact between the bent portions 13, 14, 15. Therefore, for example, the contents inside the can container X do not come into contact with the edge 12, and the occurrence of corrosion such as rust at the edge 12 can be reliably prevented. Further, since there is no step between the upper end surface of the folded portion 7 and the upper surface of the panel portion 5, the contact portion 11 can be brought into close contact with the upper surface of the folded portion 7. Intrusion of contents into the can be suppressed.

  Here, when the can container X containing the food as the contents is sealed by the can lid 1 having the above-described configuration, and the retort treatment for heat sterilizing the food is performed, the internal pressure of the can container X is increased by heating. Then, as shown in FIG. 4A, the closed portion 9 of the top surface sealing material 3 bulges upward. At the same time, the contact portion 11 of the top surface sealing material 3 is separated from the upper end surface of the folded portion 7 and the top surface sealing material 3 excluding the adhesive portion 10 is slightly extended. Thereafter, when the internal pressure of the can container X is lowered by cooling, the closed portion 9 of the top seal 3 is deformed so as to fall into the inside of the can container X from the opening 6 as shown in FIG. At this time, the abutting portion 11 abuts on the upper end surface of the folded portion 7, and further, the outer peripheral edge portion of the closing portion 9 and the bonding portion with respect to the closing portion 9 directed from the inner edge of the opening 6 toward the inside of the can container X A horizontal tension toward the center of the opening 6 is generated between the inner peripheral edge 10 and the inner peripheral edge 10. Thereby, generation | occurrence | production of the wrinkle in the inner periphery of the adhesion part 10 is suppressed, and the external appearance deterioration of the outer peripheral part of the top | upper surface sealing material 3 is prevented.

Further, as shown in FIG. 5, the top surface sealing material 3 of the present embodiment is formed in advance into a shape recessed into the opening 6 from the inner peripheral edge of the folded portion 7 toward the inside of the can container X. ing. That is, the step 16 along the inner periphery of the folded portion 7 may be formed at the peripheral portion of the closing portion 9, and the closing portion 9 inside the step 16 may be formed substantially flat. According to this, even if the internal pressure of the can container X rises due to heating during the retort process and the closed portion 9 bulges upward, the amount of bending of the closed portion 9 is large, so that the top seal 3 is extended. It is extremely small, and the generation of wrinkles at the inner peripheral edge of the bonded portion 10 can be more reliably suppressed. Moreover, since the tension applied to the bonding part 10 can be sufficiently weakened according to the change in the internal pressure of the can container X, peeling of the bonding part 10 can be reliably prevented, and high sealing performance is reliably maintained. be able to. Furthermore, since the closed portion 9 is recessed into the opening 6 at room temperature, for example, a spoon or the like for taking out food in the can container X can be accommodated in the recessed space.

Moreover , as shown in FIG. 6, you may make the panel part 5 and the folding | turning part 7 incline upwards (outward of the can container X) toward the center of the opening part 6. As shown in FIG. In this structure, the adhesive portion 10 of the top surface sealing material 3 is adhered to the upper surface of the panel portion 5 excluding the folded portion 7, and the contact portion 11 between the adhesive portion 10 and the closing portion 9 is the upper surface of the folded portion 7. It is provided so that it may contact | abut.

  According to this, when the internal pressure of the can container X rises due to heating during the retorting process, as shown in FIG. 7A, even if the closed portion 9 of the top seal 3 bulges upward, the folded portion 7, there is no or very little separation of the abutting portion 11 of the top surface sealing material 3 from the upper end surface, and entry of the contents between the folded portion 7 and the abutting portion 11 can be suppressed. In addition, the tension acting on the bonding portion 10 when the closing portion 9 of the top surface sealing material 3 bulges upward is applied in the surface direction of the bonding portion 10, so that the panel portion 5 in the bonding portion 10 Can be reliably prevented. Moreover, when the internal pressure of the can container X falls by cooling after retort processing, as shown in FIG.7 (b), the closure part 9 of the top | upper surface sealing material 3 falls inward of the can container X from the opening part 6. As shown in FIG. The contact portion 11 that contacts the upper end surface of the folded portion 7 generates a tensile force between the outer peripheral edge portion of the closing portion 9 and the inner peripheral edge portion of the adhesive portion 10. Generation | occurrence | production of the wrinkle in an inner periphery can be suppressed reliably.

Here, even when the panel part 5 and the folded part 7 are inclined upward toward the center of the opening part 6, as shown in FIG. A step 16 along the inner periphery of the folded portion 7 is formed in the peripheral portion of the turn 9, and the closed portion 9 inside the step 16 is formed substantially flat . According to this, it is possible to suppress the extension of the top seal 3 by increasing the amount of bending of the closing portion 9, and more reliably suppress the generation of wrinkles on the inner peripheral edge of the bonding portion 10 and the peeling of the bonding portion 10. be able to. And the spoon etc. for taking out the foodstuffs inside the can container X can be accommodated in the space where the closure part 9 was dented in the opening part 6, for example.

The top view which shows the can lid of the form by which this invention is not employ | adopted . Explanatory drawing which fractures | ruptures and shows a part of can lid of FIG. The elements on larger scale which show a panel part and a folding | turning part. Explanatory drawing which shows an effect | action of a top | upper surface sealing material. Explanatory drawing which shows the top | upper surface sealing material used as embodiment of this invention . The elements on larger scale which show the panel part and folding | turning part in the other can lid | cover in which this invention is not employ | adopted . Explanatory drawing which shows the effect | action of the top | upper surface sealing material in the form shown in FIG. Explanatory drawing which shows the top surface sealing material which employ | adopted this invention for the can lid shown in FIG.

Explanation of symbols

  X ... can container, 1 ... can lid, 2 ... lid frame, 3 ... top seal material, 4 ... clamping part, 5 ... panel part, 6 ... opening part, 7 ... folded part, 12 ... edge, 13 ... 1st bending part, 14 ... 2nd bending part, 15 ... 3rd bending part.

Claims (4)

A metal lid frame body provided with a tightening portion for winding on a can container at the outer peripheral edge portion and having an opening formed in a panel portion surrounded by the outer peripheral edge portion, and the opening portion from the upper surface side A can lid comprising a film-like top surface sealing material that covers and closes openably,
A plurality of folded inner edges of the opening on the upper surface side of the panel portion, and a folded portion that is housed inside the edge in a non-exposed state is provided on the entire circumference of the opening.
The top surface sealing material is adhered along the entire periphery of the opening on the panel portion excluding the folded portion, and is recessed in the opening from the inner periphery of the folded portion toward the inside of the can container. A can lid characterized in that, by being provided, the opening is sealed in an airtight state while allowing upward bulging with an increase in internal pressure of the can container .   The can lid according to claim 1, wherein an upper end surface of the folded portion and an upper surface of the panel portion are located on the same straight line in a sectional view.   The said panel part and the said folding | turning part are inclined and provided in the outward of the can container toward the center of the said opening part by making the outer periphery of the said panel part into a base end. Can lid. The folded portion includes a first bent portion formed by folding an end edge on the upper surface side of the panel portion, a second bent portion formed by folding the first bent portion on the upper surface side of the panel portion, 2 bent portions are folded back to the upper surface side of the panel portion, and the first bent portion is wound inside, and the upper surface of the panel portion and each bent portion are in close contact with each other. The can lid according to any one of claims 1 to 3, wherein an end edge is sealed inside.

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