Sealing arrangement for packaging container

Abstract

A paperboard packaging container includes a sealing arrangement comprising a lid and a sealing rim. The packaging container further includes a circumferential lid sealing member applied in the lid. The sealing rim forms a closed loop extending around the container opening. The sealing rim further comprises a first sealing surface arranged at an upper end edge of the sealing rim and is arranged to seal against a second sealing surface constituted by the circumferential lid sealing member when the lid is in a closed position. The sealing arrangement furthermore includes a frame structure forming a closed loop extending around a periphery of the container opening and is connected to the sealing rim. The lid is connected to the frame structure by a hinge member and a locking arrangement.

Claims

1. A paperboard packaging container, said packaging container comprising a container body said container body comprising a container wall extending from a container bottom to a container opening in a height direction of said packaging container, and a sealing arrangement comprising a lid and a sealing rim, said lid comprising a top portion and a side wall portion, said top portion having an outer lid surface and an inner lid surface opposite to said outer lid surface, said packaging container comprising a circumferential lid sealing member applied in said lid against an inner lid support surface, said sealing rim forming a closed loop extending around said container opening and being attached to an inner surface of said container wall at said container opening and comprising a first sealing surface arranged at an upper end edge of said sealing rim and being arranged to seal against a second sealing surface constituted by said circumferential lid sealing member when said lid is in a closed position, said sealing arrangement further comprising a frame structure, said frame structure forming a closed loop extending around a periphery of said container opening and being connected to said sealing rim, said lid being connected to said frame structure by a hinge member arranged at a first part of said frame structure and a locking arrangement being arranged on said frame structure at a second part of said frame structure, which is located opposite said first part of said frame structure, said locking arrangement comprising interengaging locking elements, wherein a first interengaging locking element is arranged in or on said outer lid surface of said lid top portion and a second interegaging locking element is arranged on or in a locking flap arranged on said frame structure and being hingedly connected to said frame structure by means of a hinge formed integrally with, or connected to, said frame structure, said circumferential lid sealing member being made from a polymeric foam having a closed-cell structure, has a no-load thickness to of from 1.5 to 5 mm and a density of from 10 to 75 kg/m.sup.3 and in that a distance d.sub.1 is defined between said first sealing surface of said sealing rim and said inner lid support surface when said lid is in a closed position and wherein t.sub.0>d.sub.1 and wherein said lid sealing member is applied in said lid with a lateral compression against said side wall portion such that the lid sealing member bulges toward the first sealing surface and a compression force of the first sealing surface against the second sealing surface of the lid sealing member when the lid is in the closed position increases.

2. The paperboard packaging container according to claim 1, wherein said sealing arrangement of said paperboard packaging container has no visual leakage present upon visual inspection at the seal between said first and said second sealing surfaces around the periphery of the container opening after a Sealing Arrangement Integrity Test that includes the following steps; a) cutting out a hole with a 2 cm hole diameter in said bottom of a paperboard packaging container according to claim 1, b) placing said paperboard packaging container up-side-down with said lid being in a closed position, c) pouring water having a temperature of 24° C. into said paperboard packaging container through said hole such that a water column of 20 mm is formed, d) let said paperboard packaging container stand up-side-down for 5 min.

3. The paperboard packaging container according to claim 1, wherein said closed-cell polymeric foam is polyethylene foam.

4. The paperboard packaging container according to claim 3, wherein the polyethylene foam is closed-cell polyethylene foam.

5. The paperboard packaging container according to claim 1, wherein said circumferential lid sealing member has a no-load thickness of at least 2.0 mm.

6. The paperboard packaging container according to claim 5, wherein the no-load thickness is from 2.0 to 4.0 mm.

7. The paperboard packaging container according to claim 1, wherein a support structure comprising a sealing member support element is arranged on said inner lid surface and forming said inner lid sealing surface, said inner lid sealing surface forming a closed loop and extending in parallel with said lid side wall portion and further being arranged such that when said lid is in a closed position said sealing member support element and said sealing rim exerts pressure on said circumferential lid sealing member from opposite directions.

8. The paperboard packaging container according to claim 1, wherein said container body has an outer surface opposite said inner surface and a container body edge at said container opening, said frame structure extending on said outer surface of said container body from said container body opening edge downwards in said height direction of said container and said sealing rim extending from said container body opening edge on said inner surface of said container body downward in said height direction of said container and upward a distance past said container body edge in said height direction of said container.

9. The paperboard packaging container according to claim 8, wherein said distance past said container body edge is at least 0.5 mm.

10. The paperboard packaging container according to claim 9, wherein said distance past said container body edge is from 1 mm to 7 mm.

11. The paperboard packaging container according to claim 10, wherein said distance past said container body edge is from 2 mm to 5 mm.

12. The paperboard packaging container according to according to claim 1, wherein said frame structure is connected to said sealing rim by a snap-in connection.

13. The paperboard packaging container according to claim 1, wherein a Compression set (C.sub.SET) of the lid sealing member at 25% compression under 22 h at 23° C., is between 10 and 20% as measured after ½ h recovery and according to standard method BS ISO 7212, 1998, the Compression set being calculated as C.sub.SET=[(t.sub.0−t.sub.i)/(t.sub.0-t.sub.n)]*100 where t.sub.i is the sealing member thickness after testing and to is the thickness of the specimen during the test.

14. The paperboard packaging container according to claim 13, wherein said distance d.sub.1 is smaller than said thickness t.sub.i.

15. The paperboard packaging container according to claim 14, wherein said distance d.sub.1 is at least 2% smaller than said thickness t.sub.i.

16. The paperboard packaging container according to claim 15, wherein said distance d.sub.1 is at least 5% smaller than said thickness t.sub.i.

17. The paperboard packaging container according to claim 1, wherein said circumferential lid sealing member is a lid sealing member.

18. The paperboard packaging container according to claim 1, wherein said interengaging locking elements are mating locking elements, said first interengaging locking element being a female locking element and said second interengaging locking element being a male locking element.

19. A lid component comprising a lid and frame structure, said lid comprising a top portion and a side wall portion, said top portion having an outer lid surface and an inner lid surface opposite to said outer lid surface, said packaging container comprising a circumferential lid sealing member applied in said lid against an inner lid support surface, said frame structure forming a closed loop and said lid being connected to said frame structure by a hinge member arranged at a first part of said frame structure, and a locking arrangement being arranged on said frame structure at a second part of said frame structure which is located opposite said first part of said frame structure, said locking arrangement comprising interengaging locking elements, wherein a first interengaging locking element is arranged in or on said outer lid surface of said lid top portion and a second interengaging locking element is arranged in or on a locking flap arranged on said frame structure and being hingedly connected to said frame structure by means of a hinge formed integrally with, or connected to, said frame structure, wherein said circumferential lid sealing member is made from a polymeric foam having a closed-cell structure, has a no-load thickness of from 1.5 to 5 mm and a density of from 10 to 75 kg/m.sup.3 and wherein said lid sealing member is applied in said lid with a lateral compression against said side wall portion; wherein the lid component is for cooperating with a sealing rim to at least partially compress the circumferential lid sealing member between the inner lid support surface and at least a portion of the sealing rim when the lid is in a closed position, and wherein the lateral tension increases a compression force on the circumferential lid sealing member between the inner lid support surface and the sealing rim when the lid is in the closed position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein:

(2) FIG. 1 illustrates a front view of a packaging container;

(3) FIG. 2 illustrates an exploded view of the packaging container in FIG. 1;

(4) FIG. 3 illustrates a container lid;

(5) FIG. 4 illustrates a circumferential lid sealing member;

(6) FIG. 5 illustrates a lid comprising a circumferential lid sealing member;

(7) FIG. 6 illustrates a detail of a container body edge with an attached sealing rim, lid and a circumferential lid sealing member

DETAILED DESCRIPTION

(8) It is to be understood that the drawings are schematic and that individual components, such as layers of material are not necessarily drawn to scale. The packaging container, sealing arrangement and circumferential lid sealing member shown in the figures are provided as examples only and should not be considered limiting to the invention. Accordingly, the scope of the invention is determined solely by the appended claims.

(9) With reference to FIGS. 1-2 there is shown a paperboard packaging container 1 for pourable or scoopable bulk solids. The particular shape of the container 1 shown in the figures should not be considered limiting to the invention. Accordingly, the paperboard packaging container according to the invention may have any useful shape or size.

(10) With reference to FIGS. 1 and 2, the packaging container 1 comprises a container body 2 formed by a tubular container wall 3 including a front wall portion 3a, a rear wall portion 3b and two side wall portions 3c, 3d. The container wall 3 extends from a container body bottom edge 4a to a container body opening edge 5a at a container body opening 5 in a height direction H of the packaging container 1. The container wall 3 has an inner surface 6 facing towards an inner compartment 8 in the packaging container 1 and an outer surface 7 facing away from the inner compartment 8 and being exposed to the exterior of the packaging container 1. A bottom disc 24 is positioned at a container body bottom 4 of the container body 2. The container body 2 is made from paperboard material as defined herein. The container body 2 may be formed by bringing together the side edges of a web of paperboard causing the material to assume a tubular shape, where after the side edges are sealed together. Sealing of the side edges may be made by any suitable method as known in the art, such as by welding or gluing, with welding being preferred. Sealing of the side edges of the container body web may involve using a sealing strip, as known in the art. The bottom disc 24 may be made from paperboard, metal, plastic, or from any suitable combination of such materials as known in the art.

(11) The container body bottom edge 4a is reinforced by a plastic bottom rim 25 which is applied to the inner surface 6 of the container wall 3, between the bottom disc 24 and the container body bottom edge 4a. The bottom rim 25 reinforces the container body paperboard bottom edge 4a, stabilizes the shape of the container body 2 and protects the container body bottom edge 4a from mechanical deformation. The plastic bottom rim 25 also serves as a protective barrier against water and other fluids which may be present on a surface on which the packaging container is placed.

(12) As an alternative to a plastic bottom rim, the bottom edge of the packaging container may be formed by a rolled edge of the paperboard container body, or may be provided by a simple, non-rolled join between the bottom disc 24 and the container body 2.

(13) The paperboard packaging container 1 is provided with a sealing arrangement comprising a lid 9 and a sealing rim 10 extending along the container body opening 5 and defining a perimeter of a container access opening which is smaller than the container body opening which is defined by the container opening edge 5a of the container body 2.

(14) The sealing rim 10 is preferably a plastic rim, most preferably a thermoplastic rim and is attached to the inner surface 6 of the container body wall 3 at the container body opening 5. The sealing rim 10 has an extension in the height direction, H, of the container 1 and has an upper end edge defining a first sealing surface 16 facing away from the container bottom 4. The sealing rim 10 extends around the full periphery of the container body opening 5. The sealing rim 10 protrudes upwards in the height direction, H, above the container body opening edge 5a, whereby the first sealing surface 16 of the sealing rim 10 is arranged above the container body opening edge 5a in the height direction, H, of the packaging container 1.

(15) The sealing rim 10 is joined to the inner surface 6 of the container wall 3 by means of a weld seal extending around the container opening 5. The weld seal preferably extends continuously around the container body opening 5 and is a sift-proof weld seal and is preferably also a moisture proof weld seal and most preferably a gas-tight weld seal.

(16) The weld seal is formed by supplying energy to heat and locally soften or melt one or more thermoplastic component in a thermoplastic sealing rim 10 and/or in a coating or film on the inner surface 6 of the container body wall 3 and by pressing the sealing rim 10 and the container wall 3 together in a direction perpendicular to the container wall 3. The temperature and pressure can be controlled and adjusted to form a strong and tight seal without damaging the welded components. The thermoplastic material used to create the weld seal may be provided by a fully or partly thermoplastic sealing rim 10, by a thermoplastic film or coating on the inner surface 6 of the container wall 3, or by both a fully or partly thermoplastic reinforcing rim and by a thermoplastic film or coating on the inner surface 6 of the container wall 3. A plastic sealing rim 10 is preferably made from thermoplastic material which allows it to be thermoformed, e.g. by injection molding. An injection molding process may be used to form plastic components having different polymer compositions in different parts of the plastic component. By way of example, the surface of a plastic sealing rim which is welded to the container body may be formed from a polymer composition having a lower softening and melting point than other parts of the reinforcing rim. Moreover, a sealing surface on the upper sealing rim 10 may be formed from a resilient thermoplastic polymer. Any suitable welding technique may be used, such as ultrasonic welding or high frequency welding, with high frequency welding being preferred.

(17) The lid 9 comprises a top portion 11 and a side wall portion 12. The top portion 11 of the lid defines an outer lid surface 13 and an inner lid surface 14. A circumferential lid sealing member 15 in the form of a lid sealing disc 15 is applied in the lid 9 against an inner lid support surface 14a (illustrated in FIG. 3), with a lid sealing disc first side 15a facing the inner lid surface 14 and a lid sealing disc second side 15b facing away from the inner lid surface 14. The sealing disc 15 is applied in the lid 9 with a lateral compression against the side wall portion 12 such that lateral tension through the lid sealing disc 15 is created.

(18) As illustrated in FIG. 3, a sealing member support element 23 is arranged on, and form part of, the inner surface 14 of the lid 9 and is in the form of a closed loop extending in parallel with the lid side wall portion 12. The distance d1 is measured from the inner lid support surface 14a, i.e. from the surface facing and supporting the sealing disc 15 when the sealing disc 15 is arranged in the lid 9 according to the present disclosure. In FIG. 3, the sealing member support element 23 includes a pattern of reinforcing ribs and tubular elements, providing supporting to the lid sealing disc 15. The inner lid support surface 14a is in the form of a closed loop extending in parallel with the lid side wall portion 12 is arranged such that when the lid 9 is in a closed position the closed loop and the sealing rim 10 exert pressure on the lid sealing disc 15 from opposite directions which will provide even further improved sealing properties of the packaging container 1. The inner side of the side wall portion 12 is also provided with a protruding rib 27 for holding the sealing disc 15 in place, in the form of a closed loop extending along the lid side wall portion 12 and protruding perpendicularly from the side wall portion 12.

(19) In FIG. 3, the lid 9 is connected by a hinge member 19 to the frame structure 18. The hinge member 19 is arranged at a first part of the frame structure 18 and a locking arrangement in the form of a locking flap 22 is arranged on the frame structure 18 at a second part of the frame structure 18. The second part of the frame structure 18 is located opposite the first part of the frame structure 18.

(20) With reference to FIG. 3, the hinge member 19 is shown to be a live hinge, formed integrally with the lid 9 and the frame structure 18 as a flexible connection between the lid 9 and the frame structure 18. As set out herein, the illustrated hinge is only intended as a non-limiting example and it should be understood that any other type of functional hinge may be used for the connection between the frame structure and the lid.

(21) The frame structure 18 is applied to the packaging container 1 at the container body opening edge 5a and is mechanically attached to the sealing rim 10 by a snap-on connection. The frame structure 18 is attached to the sealing rim 10 after the sealing rim 10 has been welded to the inner surface 6 of the paperboard container wall 3. Accordingly, the frame structure can be attached at a late stage in a process for assembling and filling the packaging container as disclosed herein. The frame structure 18 is applied to the sealing rim 10 by pressing the frame structure 18 down over the upper edge of the sealing rim 10 until the frame structure 18 locks in place on the sealing rim 10. When the frame structure 18 has been attached to the sealing rim 10, it can only be removed again by breaking or damaging the connection.

(22) FIG. 4 illustrates the lid sealing disc 15 according to the present disclosure; the thickness t.sub.0 is measured without applying any load, and is in the range from 1.5 to 5 mm. The lid sealing disc 15 has a uniform thickness.

(23) As illustrated in FIGS. 5 and 6, the lid sealing disc 15 is applied in the lid 9 and being supported by the inner lid support surface 14a (shown in FIG. 3), with the sealing disc first side 15a facing the inner lid surface 14 (shown in FIG. 3), and the sealing disc second side 15b facing away from the inner lid surface 14. The lid sealing disc 15 is made from polyethylene foam having a closed-cell structure, it has a no-load thickness in the range of from 1.5 mm to 5 mm and a density in the range of from 10 to 75 kg/m.sup.3. The lid sealing disc 15 also provides a second sealing surface 17 which will seal against the first sealing surface 16 arranged at the upper end edge of the sealing rim 10 when the lid 9 is in a closed position. A tight closure between the lid 9 and the container body 2 is thereby provided by the first sealing surface 16 on the upper rim edge and a corresponding second sealing surface 17 arranged on the lid sealing disc 15 provided in the lid 9.

(24) In order to keep the lid 9 secured in the closed position between dispensing occasions and to exert pressure on the lid sealing disc 15 upon closure of the lid 9, the sealing arrangement further comprises a locking arrangement, as seen in FIGS. 1-3 and 5-6. The locking arrangement comprises mating locking elements. A male locking element 21 is arranged on the locking flap 22 and a female locking element 20 is arranged in the outer lid surface 13 of the lid top portion 11. The male locking element 21 is constituted by one or more protrusions, such as one or more knobs or ribs arranged on the locking flap 22 and the female locking element 20 is constituted by one or more corresponding cavities or grooves arranged in the outer lid surface 13 of the lid top portion 11. The locking arrangement is preferably designed such that it exerts a force on the connection between the lid 9 and the upper rim edge by pressing the first and second sealing surfaces 16, 17 together. The interengaging locking elements may however be in the form of any type of suitable deformable snap-fit locking elements.

(25) With particular reference to FIG. 6 which illustrates the coupling between the sealing rim 10 and the frame structure 18, the sealing rim 10 is permanently attached to the inner surface 6 of the container wall 3 with a weld seam, such that a lower edge of the sealing rim 10 is facing downward in the height direction H and with the upper part of the sealing rim 10 protruding past the upper edge 5 of the container wall 3. The upper end edge of the sealing rim 10 forms a first sealing surface 16 which presses against a second sealing surface 17 constituted by the outer edge portion of the lid sealing disc 15 on a lid sealing disc second surface 15b facing the first sealing surface 16. Accordingly, the lid 9 closes on the packaging container 1 by forming a tight seal between the sealing rim 10 and the lid sealing disc 15, while the frame structure 18 provides attachment for the lid 9, and can be shaped and configured for carrying hinge elements, locking elements and stacking means without any concern for providing a tight closure between the lid and the container.

(26) FIG. 6 shows the frame structure 18 with the locking flap 22 arranged thereon and the outwardly protruding male locking element 21 which is arranged to engage with a female locking element 20 in the form of a recess arranged in the outer lid surface 13 of the lid top portion 11. The lid sealing disc 15 is applied at the inner lid surface 14 and against the inner lid support surface 14a, with a sealing disc first surface 15a facing the inner lid surface 14 and the sealing disc second surface 15b facing away from the inner lid surface 14. A protruding rib 27 extends along at least a substantial part of the circumference of the side wall portion 12 on an inner side thereof, and the sealing disc 15 is kept in place by means of the protruding rib 27. The protruding rib 27 is arranged at a distance d.sub.2 from the inner lid support surface 14a, corresponding to the thickness of the disc t.sub.0 or being slightly smaller. When the lid 9 is in a closed position and the lid 9 has been pressed down over the sealing rim 10 and the male locking element 21 has snapped into a locking engagement with the female locking element 20, the first sealing surface 16 will press against the second sealing surface 17 of the lid sealing disc 15 such that the lid sealing disc 15 forms a tight sealing between the sealing rim 10 and the lid 9.

(27) The shape of the packaging container as disclosed herein is not limited to the generally rectangular shape with rounded corners which is shown in FIGS. 1 and 2. The container body may also have a generally D-shaped footprint with an outwardly curved front wall portion and curved corners. The packaging container may also for example be generally squared, circular, triangular or oval.

(28) The rigid plastic sealing rim 10 as disclosed herein which is welded to the inner surface 6 of the container body wall 3 contributes to shape and stabilize the container body opening edge 5 and also ascertains that the container body wall is provided with a desired shape and in particular that the container body wall can be imparted with a predetermined and stable curvature. In a corresponding manner, when the packaging container as disclosed herein is provided with a bottom rim 25, the bottom rim 25 further contributes to shape and stabilize the container body bottom edge 4a.

(29) Any plastic component in the packaging container as disclosed herein such as a upper sealing rim and a lower reinforcement rim, a lid component, and a frame structure may be formed from thermo-formable or moldable plastic materials, e.g. by injection molding. Injection molding is particularly suitable for producing plastic components having a three-dimensional structure, such as the lid 9 and frame structure 18 shown in FIG. 3.

(30) It should be understood that the outer three-dimensional shape of the lid may be different from that shown in the figures.