MX2008011172A

MX2008011172A - Container.

Info

Publication number: MX2008011172A
Application number: MX2008011172A
Authority: MX
Inventors: Paul Dunwoody; Paul Claydon; James Bullock; Phil Marriott
Original assignee: Crown Packaging Technology Inc
Priority date: 2006-03-01
Filing date: 2007-02-23
Publication date: 2008-09-10
Also published as: EP1989121A1; CN101395067A; GB0604097D0; US20090032535A1; AU2007220536A1; WO2007099066A1; CA2642569A1

Abstract

A container (1) particularly for food products comprising a metal can body (2) and a combination of a ring (12) and a foil membrane (14), the combination being attached to the can body, in which the ring is made of a plastics material, wherein the inside diameter of the plastic ring is no less than the inside diameter of the can body away from the attachment location of the ring on the can body .

Description

CONTAINER FIELD OF THE INVENTION This invention relates to a container. In particular, it relates to a container which comprises the combination of a can body for products, such as food, and a closure element. The invention also includes a method for forming the combination of the can body and the closure element.

BACKGROUND OF THE INVENTION The cans for food packaging typically are of a two or three piece shape, comprising a tubular can body, either cylindrical or irregular / polygonal in transverse, with a base and closed by a can end, diaphragm, film , screw cap or other closure. The base can be integral to the body of the can to form the so-called two-piece can body, or it can be formed < > ] can body of a metal sheet tube with the edges of the metal sheet joined by a seaming of welded sides, which is then closed at both ends to form a can of three The typical food cans which are closed at one end of the can, they have seal compounds at the curled edge of a hook portion on the end cap of the can to provide tight tight seam, generally known as double seaming due to the two layers of metal in the seam - one of the body of the can and the other of the end of the can. One problem with a three-piece can body is that the seaming of welded sides provides an irregular sealing surface to the seam. The sealing compounds have to be positioned precisely and uniformly so that the resulting ring of the sealing compounds within the seaming has the correct width, thickness and position to ensure that the seaming has the required adjustment. The technology of double seaming is a precise technique, which depends on numerous factors to obtain the integrity of the seaming, which is an important feature of the sealing compounds.

Cans for other products may use different closure provisions; for example, a removable aluminum is typically seated in an intermediate metal ring, which in turn is snapped to the can body. Such a can and ring combinations are onerous to manufacture when the central disk of the ring element is generally discarded, resulting in waste of the material.

The proposals as described in Patent Reference 0001: EP 1029613 A (IMPRESS GMBH &CO) 2000-08-23 and in Patent Reference 0002: WO 2005063587 A (CROWN PACKAGING TECHNOLOGY INC) 2005-07-14 avoid wasting the center of the ring, but include additional manufacturing steps which, in turn, involve capital equipment expenses and / or additional processing time.

The patent reference: EP 0819086 B (GRABHER, WERNER) 1998-12-23 discloses a semi-finished can which opens at one end and is closed at its other end by a cup-shaped aluminum membrane. The side wall of the aluminum cup extends in the direction of the axis of the can and attaches directly to the interior of the wall of the can. The aluminum can extend over the edge of the can body, which is formed inside a hook or curl. Despite being inexpensive to manufacture, unfortunately when the cans closed in this way are stacked, the pressure of the upper can is supported directly on the aluminum, which is a risk of damage to the aluminum. In addition, the aluminum is attached to the can body on one side of the seaming which has an irregular sealing surface as described above.

Another problem with the patent reference 0004: EP 0819086 B (GRABHER, WERNER) 1998-12-23 is that the container is unsuitable for use with foods which generate positive internal pressure inside the can body during processing as it tends to to detach the aluminum from the side wall of the container.

This invention aims to overcome the problems of EP 0819086 B while still providing a container which is less expensive and causes less manufacturing waste than the ring seal and peelable aluminum membrane that was described.

SUMMARY OF THE INVENTION This invention aims to provide a can body and closure element for enclosure by a variety of closure panels (can end, diaphragm, disc etc.) at a reduced cost compared to traditional detachments.

Therefore, a first aspect of the invention provides a container comprising: a metal can body, and a combination of a ring and an aluminum membrane, the combination is coupled to the can body, in which the ring is made of a plastic material, characterized in that the inner diameter of the plastic ring is not less than the inner diameter of the can body outside the annular location of the ring in the can body.

The use of a plastic ring is cheaper than using a metal ring from which the center is generally discarded. The union between the aluminum / ring membrane combination and the can body provides a strong connection to provide a watertight seal. In addition, the aluminum / ring membrane combination covers any weld (for example, a seaming of welded sides on the side wall of a 3-piece can) and the plastic ring supports any container stacked on top, without risk of damage to the aluminum membrane.

Assuring that the inner diameter of the plastic ring is not less than the inner diameter of the can body outside the ring attachment location in the can body is beneficial to maximize the breadth of the container opening and allow it to discharge fully the product of the container. The can body can have a generally cylindrical profile, that is, with a straight or tapered side wall. In such an embodiment, the ring can be retained by the contact between the ring and the outer surface of the can body; Conveniently, retention of the ring in the can body is allowed by the ring having an outer peripheral wall and a hook portion as described below.

Preferably, however, the edge of the can body of the aluminum membrane / ring combination is comprised of an enlarged portion, all or part of the ring that is located within the enlarged portion, the inner diameter of the ring is not less than the diameter of the ring. inner diameter of the non-enlarged part of the can body. In general, the height of the ring corresponds to the axial length of the enlarged portion of the can body. Accordingly, the inner side wall of the ring extends smoothly to the inner side wall of the can body. This is beneficial to allow the complete discharge of the product from the container and is particularly useful for solid or semi-solid food products, such as cooked meats, thick soups or pet foods.

In one embodiment, the ring is permanently attached to the can body and the aluminum membrane is releasably attached to the plastic ring. The ring can be formed of a conventional thermoplastic polymer, such as polypropylene. The linkage between the ring and the can body can be improved by the selection of the coating on the can body; for example, a heat sealing film or lacquer may be applied at the interface between the ring and the can body or be pre-covered in the can body and / or the ring. The ring can be thermally sealed to the can body, for example by using heat by induction, with the application of heat which causes the lacquer that can be heat sealed to form a joint between the ring and the can body. When induction heat is used to join the ring to the can body, the aluminum membrane is typically detachably attached to the ring subsequent to the ring attachment in the can body, thus ensuring that any metal in the aluminum membrane does not interfere with the heat process by induction. The resulting container is easier to open by detachment than those in EP 0819086 B, which are not in release mode for their opening.

In a preferred embodiment, the ring is attached directly to the side wall of the can body. The plastic ring can be made of a thermoplastic polymer; it has been found that it is beneficial for the plastic ring to comprise polypropylene or modified polypropylene. The ring can then be placed in position in the can body and the appropriate heat means applied (e.g., heat by induction). The action of heat causes the surface of the ring itself to bond directly to the surface of the can body, even when the can body surface includes lacquers / coatings (e.g. coatings based on epoxy resins). Advantageously, the modified polypropylene comprises polypropylene injected with maleic anhydride. It has been discovered that such modified polypropylene forms a strong bond with conventional lacquers of the type commonly used in metal can bodies to protect the metal substrate from the can body, such as lacquers based on exoxicant resins. Polypropylene is a non-polar material, while lacquers used to protect the metal substrate of a can body (for example, lacquers based on exoxy resins) are commonly polyester materials. The addition of maleic anhydride improves the binding capacity of the non-polar polypropylene of the plastic ring with the polar lacquers provided in the can body.

The can body may comprise a loop or flange, and the ring may include a flange which is adapted to extend over the loop / flange of the can body. Preferably, the flange extends to an outer peripheral wall which depends on the flange on the outside of the can body flange / flange. Advantageously, the outer peripheral wall comprises a hook portion for clamping onto the curl / flange of the can body to hold the ring in the can body. The hook portion is useful for keeping the ring in position in the can body if the ring is fixed inside the can body by means of induction heat (or other means involving the application of heat to the ring), because this compensates for any thermal expansion or shrinkage of the plastic ring compared to the metal can body.

Conveniently, the flange includes a portion which extends upward to provide an edge for handling and flange protection. Preferably, the base of the container and the rim are formed such that the base of a first container of the present invention can be placed within the rim of a second container of the present invention, increasing the ability to stack the containers one on top of the other. .

In one embodiment, the rim of the ring is provided with a substantially flat joining surface, and the aluminum membrane is attached to this flat surface. In an alternative embodiment, the ring is provided with a connecting surface inclined downwardly at an angle of up to 60 °, and the aluminum membrane is attached to this inclined surface. It has been found that providing such an inclined joint surface allows the replication process of the container. When subjected to internal positive pressure during processing, the aluminum will expand outward to form a curved profile. The inclined joint surface ensures that the aluminum membrane is loaded primarily for shearing rather than for peeling when subjected to positive internal pressure, thus preventing the loss of the seal between the aluminum membrane and the plastic ring. More preferably, the joint surface slopes downwardly at an angle of up to 45 °.

The aluminum membrane commonly includes a retaining flange to detach the aluminum membrane from the ring. Ideally, this flange is located towards an edge of the aluminum to reduce the need for detachment force.

On the other hand, the aluminum membrane can be formed in the form of a cup (i.e., cup-shaped) and the side wall of the aluminum cup attached to the inner side wall of the ring. In this mode, it is beneficial for any flange to be positioned outwardly from the cup-shaped aluminum side wall to help removably remove the aluminum.

In a second aspect of the present invention, a method for forming a container is provided, the method comprising: forming a metal can body; permanently fixing a ring of plastic material to the can body, the inner diameter of the plastic ring is not less than the inner diameter of the can body outside the annular location of the ring in the can body; and joining an aluminum to the ring such that, in use, the aluminum can be detached from the ring to dispense a product from the container.

Preferably, the can body is formed with a radially enlarged portion at one end of the can body, and the plastic ring is permanently affixed to the can body so that all or part of the ring is located within the enlarged portion.

On the other hand, the steps of fixing the ring and joining the aluminum can be reversed in such a way that the aluminum joins the first ring and the ring combination and the aluminum is subsequently fixed to the can body.

According to a third aspect of the present invention, there is provided a container comprising: a metal can body, and a combination of a ring and an aluminum membrane, the combination is coupled to the can body, in which the The ring is made of aluminum and the ring of a plastic material, characterized in that the aluminum / ring membrane combination comprising a permanent connection between the aluminum membrane is detachably attached to the inside of the side wall of the can body.

In this aspect of the invention, the ring may include a flange or clamping ring for removing the ring and aluminum together as a single entity from the container. The respective stiffness of the plastic ring compared to the aluminum membrane may allow the container to be re-sealable by locating the aluminum membrane / ring combination in the can body.

This aspect of the invention may also include one or more of the features described above for the first aspect of the invention.

BRIEF DESCRIPTION OF THE FIGURES Preferred embodiments of the invention will now be described, by way of example only, with reference to the figures, in which: Figure 1 is a side section of a first embodiment of a container according to the invention; Figure 2 is a perspective view of the container of Figure 1; Figure 3 is a side section of a second embodiment of a container according to the invention; Figure 4 is a perspective view of the container of Figure 3; Figure 5 is the side section of a third embodiment of a container according to the invention; Figure 6 is a perspective view of the container of Figure 5; Figure 7 is a side section of a fourth embodiment of a container in accordance with the invention; Figure 8 is a side section of a fifth embodiment of a container according to the invention; Y Figure 9 is a perspective view of the container of Figure 8.

DETAILED DESCRIPTION OF THE INVENTION Figures 1 and 2 show a container 1. The container 1 is of the so-called "three-piece" type, comprising a cylindrical can body 2 which is closed at its lower end by a conventional closure 3. The closure 3 is attached to the can body 2 by a double seam. The can body 2 is radiantly enlarged by an amount "a" (in this example, approximately 2 mm) at its upper end to provide a stepped portion 5 and ends in a flange or curl 6.

The can body 2 can be formed of a sheet of metal which is covered with a lacquer, polypropylene dispersed within the lacquer. The metal sheet can then be formed inside a cylinder (for example, by welding) to provide the can body. Therefore the seaming of the welded side, which is thus formed in the can body is generally covered separately with a similar internal lacquer or with a polypropylene powder. On the other hand, the metal sheet can be coated with a conventional lacquer and a specific lacquer, such as one that includes a dispersion lacquer, used only to cover that part of the can wall and the weld that makes contact with the ring of plastic 12.

The upper end of the can body 2 is closed by a closure 10. The closure 10 includes a plastic ring component 12, and a diaphragm or aluminum 14 with a peripheral flange 16 for its opening. The plastic ring 12 is molded into a first ring 18 which is substantially cylindrical and prepared with a given shape to be seated within the stepped portion 5. In the embodiment shown, the plastic ring 12 has an internal diameter which is the same of the non-enlarged part of the can body 2. This provides a smooth transition from i) the inner side wall of the non-enlarged part of the can body 2 to ii) the inner side wall of the plastic ring 12, optimizing so both the product download. However, the alternative embodiments may have the plastic ring 12 with an internal diameter which is larger than that of the can body 2 below the stepped portion 5. In either case, the plastic ring 12 does not prevent the discharge of the product from container 1, but promotes the total discharge of the product. The plastic ring 12 is also typically of any polypropylene to bond with a polypropylene dispersion in the inner can body shell, or modified polypropylene to join with conventional lacquers.

The ring 18 of the plastic ring 12 extends radially outwardly within a flat flange portion 20 which, in turn, extends outwardly and downwardly within a retaining portion 22 and ascendingly within a edge 24. The plastic ring 12 can also be made in the shape of (for example, with a hook portion) so that it snaps into a position around the flange or curl 6 of the can body and thus conceals both any exposed metal of the flange or curl. The ring 18 is permanently attached to the can body, for example by means of induction heating. The attached region may also include curl or flange 6.

The aluminum 14 is attached to the flange portion 20 which forms a seal surface of 1.0 to 2.5 mm in width. The central region of the aluminum 14 as shown in figure 1 has an inward dome due to the negative pressure (so mentioned "empty") inside the container followed by filling or processing.

The container 1 of figures 1 and 2 is typically formed in two distinct stages. In one scenario, the can body 2 has the flange 6 formed around the periphery to which the plastic ring 12 is attached, and then the upper region of the can body 2 is radially expanded to form the stepped portion 5. The plastic ring 12 is attached to the can body 2 by fear of heat by induction, and the aluminum 14 is then attached to the plastic ring. The container 1 is filled from its lower end and the closure 3 is snapped into the filled container. In this method, aluminum 14 does not interfere with the induction heat process and the induction heat does not interfere with the releasable bond between aluminum 14 and plastic ring 12.

The example of Figures 3 and 4 is similar to those in Figures 1 and 2 but includes a flange portion 21 which slopes down the horizontal line at an angle a (in this example, twenty). "Barometric" or "extending" flanges are preferred for containers in which the lidded packaging material is deflected by a canned pressure during processing of the food product in the container and allows use in a reel and spiral replicas (or similar processes) By tilting the flange portion 21 in a downward direction, the angle a becomes larger than the angle supported by the end of the capped packing material in its outward facing position when Accordingly, the sealing surface is predominantly loaded for shearing rather than peeling, which effectively doubles the explosion pressure performance of those containers with flat flanges (such as those in Figures 1 and 2) which can be loaded in detachment mode when subjected to internal positive pressure. efferid for barometric flanges are up to 45 ° to give sufficient dome size, although in theory angles of up to 60 ° are possible.

Although the central region of the aluminum 14 of FIGS. 3 and 4 has been shown with a smooth surface, decoration for personalization or beading can be used to improve the barometric performance to allow the movement of the aluminum 14 while preventing the aluminum from collapsing.

This embodiment may be formed in the same manner as that of Figures 1 and 2. Of course, either of these two embodiments may use a stretched container of a metal sheet preform to form a side wall and integral base (i.e. seaming of welded sides), in which case the plastic ring 12 and aluminum 14 can be formed as a component which is subsequently attached to the can body 2 after filling. On the other hand, the ring 12 can be attached to the can body 2 first, the can is filled and the aluminum 14 then attached to the plastic ring.

In the alternative container shown in Figures 5 and 6, for the characteristics of the can body 2 the same reference numerals as in Figures 1 to 4 are assigned. The plastic ring 12 of this embodiment comprises a flange 13 which is extends on the edge of the can body (here it is shown as a curl 6, although the edge may be amorphous or a simple flange) and the rings 18 are seated against and permanently attached to the inner wall of the body of the can 2 of the Same as the embodiments of Figures 1 to 4. However, in Figures 5 and 6, the aluminum 14 is detachably attached to the inner wall of the plastic ring 12, rather than to a descending portion in a descending or flat manner. From the ring. In this embodiment, the aluminum 14 defines a profile in the form of a cup. This avoids the problems of direct welding of aluminum in a welding margin as can be seen from the processes described in patent reference 0005: EP 0819086 B (GRABHER) 1998-12-23. The flange 16 of FIGS. 5 and 6 is attached to the central portion of aluminum 14. This ensures that a customer releases the aluminum 14, instead of trying to remove the entire plastic ring 12 permanently attached to the can body 2.

Figure 7 shows an alternative container 1 which has a generally cylindrical can body 2 terminating at its upper end with a flange 6 on the edge of the can body. The ring 12 includes a flat flange portion 20 extending outwardly and downwardly within a retaining portion 22 and ascending within an edge 24. The retaining portion 22 terminates in a hook portion 25 which it extends partially below the flange or curl 6 to help maintain the ring 12 in the can body 2. The ring 12 is permanently attached to the can body, with the joined region including the outer surface of the curl or flange 6 As can be seen in Figure 7, in this embodiment the plastic ring 12 does not extend down along the interior surface of the can body 2, thus avoiding the need to provide an enlarged portion in the body. of tin. Accordingly, the discharge of the product from the resulting container is not prevented.

Figures 8 and 9 represent an embodiment of the invention in which a plastic ring 30 is permanently attached to the aluminum 14. As can be clearly seen from figures 8 and 9, the aluminum 14 is attached to the outer side wall of the ring of plastic 30. The combination of the plastic ring 30 and the aluminum 14 is coupled to the can body 2 releasably joining the aluminum to the inner wall of the can body 2 around the upper side wall 32 of the can body 2. The ring of plastic 30 includes a large ring style that can be pulled out of the flange 36 for easy grip when the aluminum (and ring) is removed from the container 1.

Claims

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1. - A container comprising: a metal can body, and a combination of a ring and an aluminum membrane, the combination is attached to the can body, wherein the ring is made of a plastic material, characterized in that the inner diameter of the plastic ring is not less than the inner diameter of the can body outside the annular location of the ring in the can body.

2. - The container according to claim 1, characterized in that the edge of the can body to which the aluminum / ring membrane combination engages, comprises an enlarged portion, all or part of the ring that is located within the enlarged portion, the inner diameter of the ring is not less than the inner diameter of the non-enlarged part of the body of

3. - The container according to claim 2, characterized in that the height of the ring corresponds to the axial length of the enlarged portion of the can body.

4. - The container according to any of claims 1 to 3, characterized in that the ring is directly connected to the side wall of the can body.

5. - The container according to any of the preceding claims, characterized in that the ring comprises polypropylene or modified polypropylene.

6. - The container according to claim 5, characterized in that the modified polypropylene comprises polypropylene injected with maleic anhydride.

7. - The container according to any of claims 1 to 6, characterized in that the plastic ring is permanently attached to the can body and the aluminum membrane is detachably attached to the ring.

8. - The container according to any of claims 1 to 7, characterized in that the can body comprises a loop or flange and the ring comprises a rim, the rim extends inside an outer peripheral wall which depends on the rim on the outside of the curl or flange of the can body.

9. - The container according to claim 8, characterized in that the outer peripheral wall comprises a hook portion which is fastened on the curl or flange on the body of the can to preserve the ring on the can body.

10. - The container according to any of claims 1 to 9, characterized in that the ring comprises a portion which projects upward to provide an edge, the base of the container and the edge of each is formed such that the base of a first container can be placed inside the rim of a second container.

11. - The container according to any of claims 1 to 10, characterized in that the ring is provided with a substantially flat joining surface, and the aluminum membrane is attached to this flat surface.

12. - The container according to any of claims 1 to 10, characterized in that the ring is provided with a connection surface inclined downwardly at an angle of up to 60 °, and the aluminum membrane is attached to this inclined surface.

13. - The container according to claim 12, characterized in that the joint surface is at its opposite inclined downwards at an angle of up to 45 °.

14. - The container according to any of claims 1 to 10, characterized in that the aluminum membrane is cup-shaped and the side wall of the aluminum cup is joined to the inner side wall of the ring.

15. - A method to form a container, the method comprises: forming a metal can body; permanently attaching a ring of plastic material to the can body, the inner diameter of the plastic ring is not less than the inner diameter of the can body out from the ring attachment location in the can body; Y attaching an aluminum to the ring such that, in use, the aluminum can be detached from the ring to discharge a product from the container.

16. - The method according to claim 15, characterized in that the can body is formed with a radially enlarged portion at one end of the can body, and the plastic ring is permanently affixed to the can body so that all or part of the ring are located within the enlarged portion.

17. - The method according to any of claims 15 or 16, characterized in that the steps of fixing the ring and joining the aluminum are reversed in such a way that the aluminum is first attached to the ring and the combined ring and the aluminum is subsequently fixed to the can body.

18. - A container comprising: a metal can body, and a combination of a ring and an aluminum membrane, the combination is attached to the can body, wherein the ring is made of a plastic material, characterized in that the combination of aluminum membrane / ring comprises a permanent connection between the membrane aluminum and the ring and the aluminum is detachably attached to the inside of the side wall of the body of can.