Method of producing and filling a packaging container

Abstract

A method of producing and filling a paperboard packaging container with pulverulent bulk solids includes forming a tubular container body from a paperboard sheet, the body having upper and lower body openings and a container wall extending between the upper and lower body openings and having inner and outer surfaces; closing the upper body opening with a sealing membrane attached to the inner surface; providing an upper reinforcing rim; inserting at least a lower part of the upper reinforcing rim into the tubular container body at the upper body opening; forming a weld seal between the inner surface and the inserted part of the upper reinforcing rim; presenting the body to a filling station with the bottom body opening of the container body directed upward in a vertical direction; filling pulverulent material into the body through the upwardly directed bottom body opening; and closing the bottom body opening.

Claims

1. A method of producing and filling a paperboard packaging container with pulverulent material wherein the method comprises the steps of: a) forming a tubular container body from a paperboard sheet, said container body having an upper end with an upper body opening and a bottom end with a bottom body opening and a container body wall extending in a height direction of said packaging container between said upper body opening and said bottom body opening, said container body wall having an inner surface and an outer surface, an upper end edge and a bottom end edge; b) closing said upper body opening with a sealing membrane which is attached to said inner surface of said container body wall; c) providing an upper reinforcing rim in the form of a closed loop having a main extension in a loop plane, said upper reinforcing rim having an outer contour and an inner contour and having a height in a height direction perpendicular to said loop plane with an upper rim part and a lower rim part in said height direction of said upper reinforcing rim; d) inserting said lower rim part of said upper reinforcing rim and optionally also said upper rim part of said upper reinforcing rim into said tubular container body at said upper body opening with an upper end edge of said upper reinforcing rim being outside of said container body or flush with said upper end edge of said container wall; e) forming a weld seal between said inner surface of said container wall and said inserted part of said upper reinforcing rim; f) presenting said container body to a filling station with said bottom body opening of said container body directed upward in a vertical direction; g) filling pulverulent material into said container body through said upwardly directed bottom body opening; h) closing said bottom body opening; and i) applying a lid at said upper end of said container body after closing said bottom body opening in step h, wherein steps a to f are performed before steps g to i, and step b is performed between steps a and c or is performed between steps e and f.

2. The method according to claim 1, wherein said upper end edge is directed upward in the vertical direction and said bottom end edge is directed downward in the vertical direction during steps d and e, and wherein step 1 includes turning said container body upside-down with said upper end edge directed downward in the vertical direction and said bottom end edge directed upward in the vertical direction.

3. The method according to claim 1, wherein said closing step h is carried out by attaching a bottom disc to said inner surface of said container body wall.

4. The method according to claim 1, further comprising the step of: j) applying a frame structure by mechanically attaching said frame structure to said upper reinforcing rim after closing said bottom body opening in step h, wherein application of said frame structure is performed either before application of said lid in step i or at the same time as applying said lid in step i by applying said frame structure as part of a lid component, said lid component further including said lid, said lid and said frame structure being connected by a hinge.

5. The method according to claim 4, wherein said attachment between said frame structure and said upper reinforcing rim is made by forming a snap-in connection between said frame structure and said upper reinforcing rim.

6. The method according to claim 3, further comprising the steps of: k) providing a bottom reinforcing rim in the form of a closed loop extending in a bottom rim plane, said bottom reinforcing rim having a an outer contour and an inner contour and having a height in a height direction perpendicular to said bottom rim plane with an upper rim part and a lower rim part in said height direction of said bottom reinforcing rim; l) inserting said upper rim part of said bottom reinforcing rim and optionally also said lower rim part of said bottom reinforcing rim into said tubular container body at said bottom end edge with a bottom end edge of said bottom reinforcing rim being outside of said container body or flush with said bottom end edge of said container wall; and m) attaching said bottom reinforcing rim to said inner surface of said container body wall.

7. The method according to claim 6, wherein said bottom reinforcing rim is attached by welding.

8. The method according to claim 1, wherein said weld seal between said upper reinforcing rim and said inner surface of said container body wall is formed by high frequency welding.

9. The method according to claim 1, wherein said weld seal between said upper reinforcing rim and said inner surface of said container body wall is formed continuously around said upper body opening.

10. The method according to claim 1, wherein a degassing step is performed in conjunction with said filling step g.

11. The method according to claim 10, wherein said degassing step includes supplying a protective gas to a flow of pulverulent material in the filling step g.

12. The method according to claim 10, wherein said degassing step includes performing said closing step in a protective gas atmosphere.

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 shows a perspective view of a packaging container;

(3) FIG. 2 shows a perspective view of the packaging container in FIG. 1 with an open lid;

(4) FIG. 3 shows an exploded view of the packaging container in FIG. 1;

(5) FIG. 4 shows a cross-section taken along the line IV-IV in FIG. 1; and

(6) FIG. 5 shows schematically a process for producing and filling the packaging container in FIG. 1.

DETAILED DESCRIPTION

(7) 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, reinforcing rim and lid component 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.

(8) With reference to FIGS. 1-4, 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, a paperboard packaging container produced according to the invention may have any useful shape or size.

(9) 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 in a height direction H of the packaging container 1 from a bottom end edge 4 at a bottom end of the container body to an upper end edge 5 at an upper end of the container body 2. The container body 2 has an upper body opening 6 at the upper end and a bottom body opening 6 at the bottom end. The container wall 3 has an inner surface 7 facing towards an inner compartment 11 in the packaging container 1 and an outer surface 8 facing away from the inner compartment 11 and being exposed to the exterior of the packaging container 1. A bottom disc 9 is positioned at the bottom edge 4 of the container body 2 and covers the bottom body opening 6. 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, whereafter 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 which is applied over the join between the side edges, as known in the art. The bottom disc 9 may be made from paperboard, metal, plastic, or from any suitable combination of such materials as known in the art.

(10) The container body bottom end edge 4 is reinforced by a plastic reinforcing bottom rim 10 which is applied to the inner surface 7 of the container wall 3, between the bottom disc 9 and the bottom end edge 4 and which has an outwardly directed flange 12 which covers the bottom end edge 4 and forms a bottom edge 13 of the packaging container 1. The bottom rim 10 reinforces the paperboard bottom end edge 4, stabilizes the shape of the container body 2 and protects the container body bottom edge 4 from mechanical deformation. The plastic bottom rim 10 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. The bottom rim 10 delimits a downwardly open space between the bottom disc 9 and the bottom edge 13 of the packaging container 1 which may be used to accommodate stacking elements arranged at an upper end of another packaging container when stacking two or more packaging containers on top of each other.

(11) 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 9 and the container body 2.

(12) The closure by a bottom disc 9 may be replaced by a folded bottom portion, as known in the art.

(13) The paperboard packaging container 1 is provided with a closure arrangement comprising a lid 14 and an upper reinforcing rim 15 extending along the container body opening edge 5 and defining a perimeter of a container access opening 35 which is smaller than the upper container body opening 6 which is defined by the upper end edge 5 of the tubular container body 2.

(14) The upper reinforcing rim 15 is preferably a plastic rim, most preferably a thermoplastic rim and is attached to the inner surface 7 of the container body wall 3 at the upper body opening 6. The upper reinforcing rim 15 has an extension in the height direction, H, of the container 1 and has a lower rim part 16 with a lower rim edge 17 facing towards the container bottom 9 and an upper rim part 18 with an upper rim edge 19 facing away from the container bottom 9. The upper reinforcing rim 15 extends around the full periphery of the upper body opening 6. The upper rim part 18 protrudes upwards in the height direction, H, above the upper body end edge 5, whereby the upper edge 19 of the upper reinforcing rim 15 is arranged above the upper body end edge 5 in the height direction, H, of the packaging container 1.

(15) The upper reinforcing rim 15 is joined to the inner surface 7 of the container wall 3 by means of a weld seal 20 extending around the container opening 6. The weld seal 20 preferably extends continuously around the upper 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 20 is formed by supplying energy to heat and locally soften or melt one or more thermoplastic component in a thermoplastic rim 15 and/or in a coating or film on the inner surface 7 of the container body wall 3 and by pressing the reinforcing rim 15 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 20 may be provided by a fully or partly thermoplastic reinforcing rim 15, by a thermoplastic film or coating on the inner surface 7 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 7 of the container wall 3. A plastic reinforcing rim 15 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 reinforcing 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, an abutment surface on the upper reinforcing rim 15 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 14 is formed from an outer lid part 14a and an inner lid part 14b. The outer lid part 14a is a profiled part with a three-dimensional shape providing an upper outer surface 25 of the lid 14. As is shown in FIG. 3, the outer lid part 14a has an inner surface 26 comprising a pattern of reinforcing ribs 27. The inner lid part 14b is a planar disk. The inner lid part 14b has an inner lid surface 24 which faces towards the bottom disc 9 when the lid 14 is closed on the container access opening 35.

(18) The outer lid part 14a is connected by a hinge 29 to a frame structure 30, the lid 14 and the frame structure 30 together forming a lid component 31. The hinge 29 is a live hinge, formed integrally with the upper lid part 14a and the frame structure 30 as a flexible connection between the upper lid part 14a and the frame structure 30. 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. Moreover, the lid may be of the removable kind, without any permanent connection to the frame structure.

(19) The frame structure 30 is applied to the packaging container at the container body opening edge 5 and is mechanically attached to the upper reinforcing rim 15 by a snap-on connection. The frame structure 30 is attached to the upper reinforcing rim 15 after the reinforcing rim 15 has been welded to the inner surface 7 of the paperboard container wall 3. The frame structure 30 is applied to the upper reinforcing rim 15 by pressing the frame structure 30 down over the upper edge 19 of the upper reinforcing rim 15 until the frame structure 30 locks in place on the upper reinforcing rim 15 by means of mating snap-in features on the upper reinforcing rim 15 and the frame structure 30. When the frame structure 30 has been attached to the upper reinforcing rim 15, it can only be removed again by breaking or damaging the snap-in connection between the rim 15 and the frame structure 30.

(20) The interior compartment 11 is sealed at the upper end of the container body 2 with a fully or partly removable sealing membrane 33 which is sealed to the container body wall 3.

(21) The interior compartment is filled with pulverulent material 34. The removable sealing membrane 33 may be attached to the container wall either from the top end of the container body 2 or from the bottom end of the container body 2 as disclosed herein.

(22) In order to gain a first access to the packaged goods, a user needs to open the lid 14 and expose the packaged pulverulent material 34 by fully or partly removing the sealing membrane 33. The sealing membrane 33 may be arranged to be peeled away from the wall 3 of the container body 2 or may be arranged with means for breaking the membrane 33 so that it can be at least partly removed through the access opening 35. Such means may be in the form of one or more predefined weakenings, such as perforations or a cut partly through the membrane. When the membrane is of the tear-open type, a narrow edge part of the sealing membrane may be left at the inner surface 7 of the container wall 3. Any such remaining part of the sealing membrane should preferably not be so large so that it extends into the access opening which is defined by the inner perimeter of the upper reinforcing rim.

(23) Once the sealing membrane 33 has been removed, it is sufficient to open the lid 14 in order to gain access to the packaged goods 34 in the interior compartment 11 through the access opening 35. As is seen in FIG. 2, which reveals the inside of the upper reinforcing rim 15, the area of the access opening 35 is defined by an inner perimeter 28 or inner contour of the upper reinforcing rim 15. As the upper reinforcing rim 15 is applied on the inner surface 7 of the container body wall 3 and adds thickness to the body wall in an inward direction, the area of the access opening 35 is always smaller than the area of the upper body opening 6.

(24) When the packaging container 1 is open, a desired quantity of the packaged goods 34 may be removed from the packaging container 1 through the access opening 35 either by means of a scoop (not shown) or by pouring. The scoop may preferably be provided together with the packaging container 1. The scoop may initially be placed on the sealing membrane 33, may be removably attached to the inner lid surface 26 or may be attached to the upper reinforcing rim 15.

(25) A packaging container as shown in FIGS. 1-4 may be produced and filled by the method illustrated in FIG. 5. The method involves forming a tubular container body 2 from a paperboard sheet 2 by bringing together the side edges 67,68 of the paperboard sheet 2, thus causing the material to assume a tubular shape. The side edges 67,68 of the paperboard sheet are then 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. In the process in FIG. 5, the side edges 67,68 of the container body sheet 2 are sealed using a sealing strip 69. The use of a sealing strip 69 is optional to the invention.

(26) The container body 2 has an upper end 70 with an upper body opening 6 and a bottom end 71 with a bottom body opening 6 and a container wall 3 extending between the upper end 70 and the bottom end 71. The container wall has an inner surface 7, an outer surface 8, an upper end edge 5 and a bottom end edge 4.

(27) The upper body opening 6 is closed by applying a sealing membrane 33 across the opening 6 and attaching a peripheral edge portion of the sealing membrane 33 to the inner surface 7 of the container wall 3 at a distance from the upper end edge 5 of the container wall 3. The sealing membrane 33 is preferably attached by being welded to the inner surface 7 of the container wall 3. The weld seal 72 may be a peelable seal or a permanent seal. If the weld seal is a permanent seal, the sealing membrane 33 is preferably provided with means to allow it to be torn open by a user. Such tearing means may be perforations or other tear indications as disclosed herein.

(28) An upper reinforcing rim 15 in the form of a closed loop with a main extension in a loop plane is subsequently provides. The upper reinforcing rim 15 has an outer contour and an inner contour and a height in a height direction perpendicular to the loop plane. The upper reinforcing rim 15 has an upper rim part 18 and a lower rim part 16 in the height direction of the upper reinforcing rim 15 and is applied to the container body by inserting the lower rim part 16 into the upper body opening 6 of the container body 2. As set out herein, also the upper part 18 of the upper reinforcing rim 15 may be inserted into the container body. However, it should be ascertained that no part of the upper body end edge protrudes above the upper edge of the inserted upper reinforcing rim 15.

(29) Accordingly, the upper reinforcing rim 15 is inserted into the container body 2 such that an upper end edge of the upper reinforcing rim 15 remains outside of the container body 2 or is flush with the upper end edge 5 of the container wall 3.

(30) By inserting the upper reinforcing rim 15 which is more rigid than the container body 2 into the container body, the upper end edge 5 of the container body 2 is brought to conform to the outer contour of the upper reinforcing rim 15. Accordingly, the application of the upper reinforcing rim 15 to the container body wall 3 serves to bring the upper end edge 5 and thereby also the container wall 3 to assume a cross-sectional shape following the contour of the upper reinforcing rim 15.

(31) A weld seal 20 is thereafter formed between the inner surface 7 of the container wall 8 and the inserted lower part 16 of the upper reinforcing rim 15. As described herein, the weld seal is preferably a high frequency weld seal and is formed by applying heat and pressure perpendicular to the container wall 3 to melt and locally soften thermoplastic components in the upper reinforcing rim 15 and/or on the inner surface 7 of the container body wall 3.

(32) The partly assembled packaging container is then turned upside-down as indicated by the arrow A until the bottom body opening 6 and the bottom end 71 of the container body 2 comes to be directed upward and is introduced into a filling station where pulverulent material is filled into the container body 2 through the upwardly directed bottom body opening 6.

(33) It should be understood that the upper reinforcing rim 15 may alternatively be attached while the packaging container 1 is in the upside-down position shown after the arrow A. In such case, the packaging container 1 already has the correct orientation when presented to the filling station and no turning step is carried out. The orientation of the packaging container during the initial steps of forming the tubular container body 2, applying the inner sealing membrane 33 and the upper reinforcing rim 15 is not critical to the invention. It is to be understood, that the container body 2 may be held in any suitable position during these process steps as long as it is presented to the filling station with the bottom opening directed upwardly as shown after the arrow A in FIG. 5.

(34) Subsequently, the bottom body opening 6 is closed by attaching a bottom disc 9 to the inner surface 7 of the container body wall 3 such that the pulverulent material 34 becomes enclosed in an inner compartment between the sealing membrane 33 and the bottom disc 9. While the bottom disc may be made from any suitable material such as paperboard, plastic or metal, paperboard bottom disks may generally be preferred. The paperboard bottom disc 9 may be attached by welding, such as by high frequency welding, to the inner surface 7 of the container body wall 3. The bottom disc 9 is shaped before insertion into the bottom body opening 6 by bending the peripheral edges of the bottom disc 9 to create a flange that can be welded to the inner surface 7 of the container body wall 3. The weld seal between the bottom disc 9 and the container body wall 3 is much less sensitive to contamination by the packaged pulverulent material 34 than is the weld seal 72 between the inner sealing membrane 33 and the inner surface 7 of the container body wall 3. The bottom disc 9 is generally thicker and more compressible than the sealing membrane 33 and is easier to form into a tight seal with the container body wall 3. Furthermore, the amount of pulverulent material 34 which may escape out of the packaging container 1 when the bottom disc 9 is inserted into the bottom body opening 6 is very small, as the bottom disc 9 is only inserted a very small distance into the container body 2, thus generating only a minimum of turbulence at the surface of the packaged pulverulent material 34. In addition, any pulverulent material which ends up on the outside of the bottom disc 9 after the packaging container has been closed can be easily removed and will never be seen by a user of the packaging container.

(35) After the bottom disc 9 has been applied over the bottom body opening 6, a bottom reinforcing rim 10 is attached to the inner wall 7 of the container body 2 at the bottom end 71 of the container body 2. The bottom reinforcing rim 10 has a an outer contour and an inner contour and a height in a height direction perpendicular to a bottom loop plane and has an upper rim part and a lower rim part in the height direction of the bottom reinforcing rim 10. By inserting the upper rim part of the bottom reinforcing rim 10 and optionally also the lower rim part of the bottom reinforcing rim 10 into the tubular container body 2 at the bottom end edge 4 of the container body 2, the bottom end edge 4 of the container body 2 is brought into conformance with the outer contour of the bottom reinforcing rim 10. As with the upper reinforcing rim 15, the bottom reinforcing rim 10 may have a bottom end edge outside of the container body 2 or flush with the bottom end edge 4 of the container wall 3.

(36) The application of a bottom reinforcing rim 10 to the bottom end of the packaging container is optional to the process as disclosed herein.

(37) The partly assembled packaging container is then turned again as indicated by the arrow B until the upper end 70 of the container body 2 comes to be directed upward whereafter a lid component 31 including a lid 14 and a frame structure 30 is snapped onto the upper reinforcing rim 15 to produce the fully assembled and filled packaging container 1.

(38) It is to be understood that the upper body opening 6 may alternatively be closed with the sealing membrane after the upper reinforcing rim 15 has been applied to the container body 2. A further alternative is to apply the sealing membrane 33 from the bottom end 71 of the container body 2 which is preferably be done after the container body has been turned upside-down as indicated by the arrow B in FIG. 5. Accordingly, the sealing membrane 33 can be applied at any suitable point in the process, as long as it is applied before the filling step, as the sealing membrane 33 is needed to keep the pulverulent material in the container body 2 during the filling step.

(39) It is also to be understood that it is optional to the process as disclosed herein to apply a frame structure/lid component to the upper reinforcing rim 15. Accordingly, the filled and bottom-sealed packaging container may alternatively be provided with a lid which is directly applied to the upper reinforcing rim 15, either as a completely removable lid or as a lid which is attached to the upper reinforcing rim 15 by means of a two-part hinge.

(40) It is an advantage of a lid construction as shown in the figures that a frame structure 30 or a whole lid component 31 can be attached to the upper reinforcing rim 15 after the container 1 has been filled and closed around the contents 34. In this manner, the risk that the lid component 31 or frame structure 30 is damaged in the production and filling process is minimized. Furthermore, by attaching a three-dimensionally shaped lid component 31 or frame structure 30 at a late stage in the process, the packaging container 1 can be filled from the bottom end of the container body 2, which means that the sealing membrane 33 can be applied in the packaging container before the container is filled. An advantage with applying the sealing membrane 33 in the packaging container before the packaging container is filled with pulverulent material is that there is no risk that the seal between the membrane and the container wall is contaminated by the pulverulent material. Furthermore, there is no risk that any of the packaged pulverulent material will end up outside the sealing membrane, in the space between the lid and the sealing membrane, which may happen if the sealing membrane is applied after filling of the packaging container. A user opening a new packaging container for a first time and finding some of the contents outside the sealing membrane would consider the container to be less hygienic and reliable than a container in which the space between the sealing membrane and the lid is completely clean.

(41) By arranging the seal between the container wall and the reinforcing rim on the inside of the container wall as disclosed herein, the join between the reinforcement rim 15 and the container wall 3 forms a continuous barrier on the inside of the container. The plastic reinforcement rim 15 is more rigid than the container wall 3 and constitutes a shape stable continuation of or supplement to the paperboard container wall 3 and provides a first abutment surface which is resistant to deformation when pressed against a second abutment surface on the inner surface of the lid 14 and permits the packaging container 1 to be repeatedly opened and closed without risk of damaging the upper body end edge 5 and thereby impairing container tightness. The effective weld seal 20 between the reinforcing rim 15 and the inner surface 7 of the container wall in conjunction with the non-deformable abutment surface on the reinforcement rim 15 provide a container as disclosed herein with improved resealability and tightness after a first opening of the container by a consumer and after any internal sealing membrane or other transport seals have been broken.