SE1650995A1

SE1650995A1 - Sealing disc for packaging container with controlled internal pressure.

Info

Publication number: SE1650995A1
Application number: SE1650995A
Authority: SE
Inventors: Holka Simon; Larsson Lennart; Herlin Henrik; Sioeland Maria
Original assignee: A & R Carton Lund Ab
Priority date: 2016-07-06
Filing date: 2016-07-06
Publication date: 2018-01-07
Also published as: CN109476397B; EP3481733A1; CN109476397A; ES2870076T3; SE542047C2; EP3481733B1; WO2018009130A1; EP3481733A4; PL3481733T3

Abstract

The present disclosure relates to a paperboard sealing disc (10) for use in a paperboard packaging container (1) for bulk solids. The packaging container (1) comprises a container body (2) with an upper end (4) with an upper body opening (5’) and a bottom end (6) with a bottom body opening (5”), a container wall (3) extending between the upper end (4) and the bottom end (6) in a longitudinal direction (L). The container wall (3) has an inner surface (7) facing towards an inner compartment (9) in the packaging container (1) and an outer surface (8) facing away from the inner compartment (9). The sealing disc (10) is intended for sealing the upper body opening (5’) or the bottom body opening (5”). The sealing disc (10) comprises a sealing disc border (11) surrounding a sealing disc base portion (12), wherein the border (11) is delimited from the disc base portion (12) by a sealing disc inner folding edge (31). The sealing disc border (11) is intended to be flexed at the inner folding edge (31 ) to project out of a main plane of the sealing disc (10) and to be aligned with and sealed to the inner surface (7) of the container wall (3). The sealing disc (10) comprises one or more distance element(s) (14) arranged in the sealing disc border (11), the distance element(s) (14) having a height (H), as measured from the surface of the sealing disc border (11 ).

Description

SEALING DISC FOR PACKAGING CONTAINER WITH CONTROLLED INTERNALPRESSURE TECHNICAL FIELD The present disclosure pertains to a paperboard sealing disc for use in a paperboardpackaging container for bulk solids. The present disclosure also relates to a method for producing a paperboard packaging container comprising the paperboard sealing disc.BACKGROUND When packaging consumer goods, and in particular when packaging bulk solids, such asdry flowable consumer goods, it is common to use rigid paperboard packaging containerswhich serve as protective transport and storage containers at the retail end and as storageand dispensing containers at the consumer end. Such paperboard containers are usuallyprovided with an openable and closable lid, and with an inner removable or breakabletransport closure which keeps the contents fresh and protected against contamination up until the container is opened by a consumer.

The bulk solids may be filled into a paperboard packaging container either from thecontainer top or from the container bottom. ln packaging systems where the paperboardpackaging container is sealed by a sealing disc, such as an upper transport sealingmember or a bottom sealing disc when the packaging containers are filled from thebottom, it has been found that a pressure above the ambient pressure may be built upwithin the packaging container when the sealing disc is pressed into the opening, upperopening or bottom opening, during sealing of the packaging container subsequent to thefilling step. For such packaging systems it has been found that there exists a need to improve control of the pressure within the packaging container.

SUMMARY One object of the present disclosure is to provide a paperboard sealing disc for use in apaperboard packaging container which enables a controlled and stabilized pressure withinthe packaging container during sealing of the paperboard packaging container.

This and other objects of the present disclosure may be achieved by a paperboard sealingdisc for use in a paperboard packaging container according to claim 1. Further 2 embodiments are set out in the dependent claims, in the following description and in the drawings.

As such, the present disclosure relates to a paperboard sealing for use in a paperboardpackaging container for bulk solids. The packaging container comprises a container bodywith an upper end with an upper body opening and a bottom end with a bottom bodyopening, a container wall extending between the upper end and the bottom end in alongitudinal direction. The container wall has an inner surface facing towards an innercompartment in the packaging container and an outer surface facing away from the innercompartment. The sealing disc is intended for sealing the upper body opening or thebottom body opening. The sealing disc comprises a sealing disc border surrounding asealing disc base portion, wherein the border is delimited from the disc base portion by asealing disc inner folding edge. The sealing disc border is intended to be flexed at theinner folding edge and to project out of a main plane of the sealing disc and to be alignedwith and sealed to the inner surface of the container wall. The sealing disc comprises oneor more distance e|ement(s) arranged in the sealing disc border, the distance e|ement(s) having a height (H), as measured from the surface of the sealing disc border.

The purpose of the distance elements is to form air conveying passages between thesealing disc border and the inner wall of the packaging to allowing air/gas to pass outbetween the sealing disc and the container wall in a controlled manner when applying thesealing disc in either the upper body opening or the bottom body opening, depending on inwhich end the packaging container is finally sealed. The provision of air conveyingpassages between the sealing disc and the inner wall of the packaging container makes itpossible to control the pressure level within the inner compartment of the packaging container during and after production of the packaging container.

As may be understood by the skilled person, an alternative to provide the sealing disc withdistance elements and air passages is to include air passages in the packaging container inner wall.

The paperboard sealing disc is suitably applied after the paperboard packaging containerhas been filled from the upper body opening, after the bottom body opening has beenclosed, or alternatively after the paperboard packaging container has been filled from thepackaging bottom, after the upper body opening has been initially closed, and in which a 3 pressure above ambient pressure may be produced within the inner compartment of thepackaging container, such as when the sealing disc is pressed into either the upper bodyopening or the bottom body opening for final sealing of the packaging container inner compartment.

The fact that the sealing disc provides air conveying passages during the assembly stepsallows for a controlled and predetermined amount of air or gas passing out from the innercompartment of the packaging container when sealing the container inner compartmentafter filling. The air conveying passages are provided between the border forming a flangeand the inner surface of the container wall and are formed by the one or more distanceelement(s) to provide for controlled air outlet when the inner pressure rapidly rises abovethe ambient pressure during production of the packaging container. After attachment ofthe borders to the inner surface of the container wall, the distance elements arecompressed, but will remain identifiable as compression marks at the outer surface of thesealing disc border. As the distance elements are provided prior to closing the bottom body opening, the container wall does not comprise any compression marks.

A controlled and stabilized pressure within the inner compartment in a closed packagingcontainer has been found to be advantageous as it contributes to ensuring a uniformpressure level within the inner compartment between different packaging containersproduced in the same production line. The fact that the inner compartments of allpackaging containers produced in the same run have a uniform inner pressure gives theadvantage of uniformly shaped packages which are easier to arrange in uniform and stable stacks and to provide with a secondary package.

The bulk solids may be a pulverulent material.

The sealing disc is defined by outer edges, the distance elements may extend all the way to the outer edges or may be arranged at a distance from the outer edges.

Optionally, the sealing disc comprises two or more distance elements arranged side-by-side in the sealing disc border and defining at least an air conveying passages betweenthe distance elements. The air conveying passage(s) is present before attachment of theflange to the inner surface of the container wall when the distance elements are compressed and the distance between the compressed distance elements corresponds to 4 the width of the air conveying passages. Optionally the sealing disc comprises at least 4 or6 or 10 distance elements, such as between from 3 and 80 distance elements, such as between from 20 to 100 distance elements.

The distance elements may be equidistantly distributed along the sealing disc border.

Optionally, the distance elements are provided at the sealing disc inner folding edgeand/or with a distance of not more than 1 mm from the sealing disc inner folding edge.Optionally, the distance elements are provided with a distance within the range of from 0 to 0.1 mm from the sealing disc inner folding edge.

The fact that the distance elements are provided at the sealing disc inner folding edgeand/or with a distance of not more than 1 mm from the sealing disc inner folding edge,such that the distance element(s) are provided on or close to the inner folding edge,contributes to that the air conveying passages remain open towards the innercompartment of the packaging container during insertion of the sealing disc into thebottom body opening, thus allowing a free passage of air or gas out from the innercompartment when the inner pressure rapidly raises above the ambient pressure during production of the packaging container.

The sealing disc inner folding edge is thus arranged along the line where the sealing discborder is intended to be flexed when introduced into the paperboard packaging container,such that the sealing disc border may be attached to the inner wall of the container wall.The sealing disc inner folding edge may be an imaginary inner folding edge prior toinsertion of the sealing disc into the packaging container or may also constitute of a pre-formed folding line or crease line facilitating folding along the inner folding edge beforefolding the sealing disc such that the sealing disc border is flexed and shaped to aperipheral flange.

Optionally, the distance elements are elongated distance elements having a length of atleast 1 mm, such as from 1 to 15 mm, and form air conveying passage(s) in the form of air conveying channel(s) having a length of at least 1 mm, such as from 1 to 15 mm.

The distance element(s) may be elongated distance element(s) extending from, or over, the sealing disc inner folding edge to the sealing disc outer edges.

The fact that the distance elements have a length L of at least 1 mm and thus form one ormore air conveying channels of at least 1 mm gives an effective passage-way between theinner compartment and the outside of the packaging container during production of thepackaging container, allowing air or other gaseous media to flow out from the innercompartment of the packaging container when the pressure within the inner compartment raises above the ambient pressure.

Optionally, the elongated distance elements extend across the sealing disc inner folding edge and on to the sealing disc base portion.

Optionally, the height of the distance elements is 0.005 mm or more, such as from 0.005mm to 3 mm, or such as from 0.003 mm to 1 mm, the height H being measured from theinner surface of the sealing disc, i.e. the surface intended to face the inner surface of the container wall.

The height H of the distance elements being at least 0.005 mm, such as within the rangeof from 0.005 mm to 3 mm, implies a corresponding depth of at least 0.005 mm, such asbetween 0.03 mm to 1 mm of the one or more air conveying passage(s) defined betweenthe distance elements during insertion of the sealing disc and ensures an effective openpassage for air or other gaseous media out from the inner compartment of the packagingcontainer when the pressure within the inner compartment exceeds the ambient pressure during production of the packaging container as disclosed herein.

Optionally, the sealing disc has a longitudinal direction y and a transverse direction xperpendicular to the longitudinal direction with a length of the sealing disc as measured inthe longitudinal direction being greater than a width of the sealing disc in the transversedirection, and first and second longitudinal opposing border having a main extension in thelongitudinal direction. The sealing disc may further have first and second transverseopposing side portions having a main extension in the transverse direction. The first andsecond longitudinal opposing side portions and the first and second transverse opposingside portions extend between corner portions, which are preferably curved corner portions,such as corner portions having a radius of curvature within the range of from 5 to 60 mm,preferably within the range of from 10 to 40 mm, more preferably within the range of from15 to 30 mm. The sealing disc may preferably have a modified rectangular shape with 6 rounded corner portions. A modified rectangular shape as used herein, includes shapeswith rounded corner portions and linear iongitudinal and transverse side portions as wellas those shapes wherein one or more of the longitudinal and transverse side portions ofthe sealing disc is slightly curved, e.g. with a radius of curvature within the range of from200 to 700 mm, preferably within the range of from 300 to 600 mm, more preferably withinthe range of from 400 to 500 mm.

The distance elements may extend side-by-side between the first and second iongitudinalopposing border in the transverse direction of the sealing disc or with at least a mainextension in the transverse direction of the sealing disc, i.e. the distance elements mayextend at a small angle to the transverse direction, such as at a deviation from the transverse direction of the sealing disc of at most 20°.

The distance elements may extend parallel to each other or with an angle between them.

The distance elements may also intersect with each other at the sealing disc base portion.

For reasons of stability and improved deformation resistance of the sealing disc, it may bepreferred to arrange distance elements extending parallel to each other in the transverse direction of the sealing disc As set out herein, the corner portions may be curved portions and may be free of distance elements.

Corner portions which are free from distance elements improve the seal between theflange and the inner surface, as it reduces the risk of wrinkles being formed adjacent tothe distance elements in the border when folding the border to form a flange. Wrinkles inthe folded flange portion of the sealing disc may othenNise impair the seal between the flange of the sealing disc and the inner surface.

Optionally, at least two distance elements extend across the sealing disc forming at leastone air conveying channel extending between two opposing disc side portions and overthe sealing disc base portion. The border may be the first and second iongitudinal opposing side portions and/or the first and second transverse opposing side portions.

Distance elements extending across the sealing disc and over the sealing disc base portion may provide increased stability to the sealing disc during application of the sealing 7 disc into the sealing end as there will be a certain pressure against the sealing disc provided by the compressed air which may cause deflection of the sealing disc.

By “sealing disc base portion” is meant a portion of the sealing disc surrounded by aperipheral sealing disc portion comprising the borders of the sealing disc forming theperipheral flange.

The fiange of the sealing disc is either preformed or formed when closing the upper orbottom body opening by pressing a sealing disc into the upper or bottom body opening. Atypical size ratio of the sealing disc surface area to the relevant upper or bottom bodyopening surface area may be 1.05 or more, such as from 1.0 to 1.2. The border of thesealing disc may be deformed and flexed when the sealing disc is pressed into the bodyupper/bottom opening, such that the border of the sealing disc forms a fiange projectingout of a main plane of the sealing disc, the fiange is then aligned with the inner surface of the container body wall.

Optionally, the distance elements comprise or consist of embossed dots or lines in thesealing disc. An embossed distance element in the form of a dot may have a diameterwithin the range of from 1 to 4 mm and an embossed distance element in the form of a linemay have a width or diameter within the range of from 1 to 4 mm. The embossed elementsin the sealing disc may be in the form of straight or curved lines, with dots or straight linesgenerally being preferred.

Optionally, the distance elements comprise or consist of reinforcing strips.

Optionally, the sealing disc comprises at least four air conveying passages.

Optionally, the sealing disc comprises reinforcing elements in addition to the elongatedridge elements, such as reinforcing elements provided in, and extending only within, thesealing disc base portion. Such additional reinforcing elements need not be arranged toprovide gas passages and can take on any suitable shape such as circles, H-shapes, X-shapes, as well as logos, text, graphics, etc.

The reinforcing elements provide the sealing disc with enhanced rigidity, which may beadvantageous during insertion of the sealing disc into the upper/bottom end opening as 8 there will be a certain pressure exerted on the sealing disc by the rapidly compressed airin the inner compartment. The elevated pressure inside the packaging container maycause deflection of the sealing disc. By the provision of reinforcing elements in the sealingdisc, deflection of the sealing disc may be reduced whereby the reinforcing elementscontribute to creating a controlled and predetermined pressure within the inner compartment of the packaging container.

Optionally, the sealing disc is a bottom disc.

When the sealing disc is a bottom disc, the packaging container is first closed at the upperbody opening with an inner partly or fully removable transport closure forming a cross-sectional seal between the inner compartment in the container body and the upper bodyopening. The packaging container is subsequently filled from the bottom body openingwith the bulk solids and finally the packaging container is sealed with the sealing disc according to the present disclosing, the sealing disc thus being a bottom disc.

Optionally, the sealing disc is an inner partly or fully removable transport closure whichmay form a cross-sectional seal between the inner compartment in the container body and the upper body opening.

When the sealing disc is an inner partly or fully removable transport closure, the packagingcontainer is first closed at the bottom body opening by means of a bottom disc or foldedbottom portions, as known in the art. The packaging container is subsequently filled withthe bulk solids from the upper body opening and finally the packaging container is sealedwith the sealing disc as disclosed herein, the sealing disc thus being an inner partly or fully removable transport closure.

The shape of the sealing disc corresponds to the shape of the container body at thecontainer upper body opening when the sealing disc is an inner partly or fully removabletransport disc or to the bottom body opening when the sealing disc is a bottom disc. Theshape of the packaging container at the bottom of the packaging container may be further stabilized by means of a reinforcing bottom rim, such as a plastic bottom rim. 9 ln a second aspect, the present disclosure relates to a method of producing and filling a paperboard packaging container with bulk solids according to the first aspect wherein the sealing disc is a bottom disc, wherein the method comprises the steps of: a) b) d) e) forming a tubular container body from a paperboard sheet, the container body havingan upper end with an upper body opening and a bottom end with a bottom bodyopening and a container body wall extending in a height direction (H) of the packagingcontainer between the upper body opening and the bottom body opening, thecontainer body wa|| having an inner surface and an outer surface, an upper end edgeand an bottom end edge; attaching an inner partly or fully removable transport closure to the inner surface ofthe container body wall and/or closing the upper body opening with a container lid (16)and; presenting the container body to a filling station with the bottom body opening of thecontainer body directed upward in a vertical direction; filling bulk solids into the container body through the upwardly directed bottom bodyopening; closing the bottom body opening by pressing a sealing disc into the bottom bodyopening, the sealing disc comprising a sealing disc border surrounding a sealing discbase portion, the sealing disc border being formed into a flange by being flexedtowards the upper end in the longitudinal direction, the sealing disc comprising one ormore distance e|ement(s) being arranged in the sealing disc border on an innersurface facing the container body wall, the distance elements having a height in adirection perpendicular to the longitudinal direction of the container wall, with two ormore air conveying passages being defined on each side of the one or more distancee|ement(s) and between the inner surface of the sealing disc border and the containerwa||, and; attaching the flange to the inner surface of the container body wall. ln a third aspect, the present disclosure relates method of producing and filling a paperboard packaging container with bulk solids according to the first aspect wherein the sealing disc is a an inner partly or fully removable transport closure, characterized in that the method comprises the steps of: a) forming a tubular container body from a paperboard sheet, the container body having an upper end with an upper body opening and a bottom end with a bottom bodyopening and a container body wall extending in a height direction of the packaging container between the upper body opening and the bottom body opening, thecontainer body wall having an inner surface and an outer surface, an upper end edgeand an bottom end edge; b) closing the bottom body opening; c) presenting the container body to a filling station with the upper body opening of thecontainer body directed upward in a vertical direction; d) filling bulk solids into the container body through the upwardiy directed upper body opening; e) closing the upper body opening by pressing a sealing disc into the upper bodyopening, the sealing disc comprising a sealing disc border surrounding a sealing discbase portion, the sealing disc border being formed into a flange by being flexedtowards the upper end in the height direction, the sealing disc comprising one or moredistance e|ement(s) being arranged in the sealing disc border on an inner surfacefacing the container body wall, the distance elements having a height in a directionperpendicular to the longitudinai direction of the container wall, with two or more airconveying passages being defined on each side of the one or more distancee|ement(s) and between the inner surface of the sealing disc border and the containerwall, and; f) attaching the flange to the inner surface of the container body wall.

Optionally, the sealing disc comprises two or more distance elements arranged side-by-side in the sealing disc border and defining one or more air conveying passages betweenthe distance elements, and wherein the air conveying passage(s) defined between the distance elements has/have a width of from 1 to 20 mm.

Optionally, the height of the distance elements is at least 0.005 mm, such as from 0.005mm to 3 mm, as measured from the inner surface of the sealing disc border. Optionally, the height of the distance elements is at least 0.03 mm, such as from 0.03 mm to 1 mm.

Optionally, the sealing disc is pre-formed and already flexed and shaped to a flangebefore being pressed into the body upper/bottom opening.

Optionally, and according to the second or the third aspect, the flange of the sealing discis attached to the inner surface of the container wall by means of a welded gas tight seal in step g) or f) respectively. 11 The welding process provides a highly controlled way of creating a seal with apredetermined tightness between the seaiing disc and the paperboard container wall. Theseal is made by supplying energy to heat and locally soften or melt one or morethermoplastic component on the inner surface of the container wall and on the seaiing discand by pressing the seaiing disc and the container wall together in a directionperpendicular to the container wall. The thermoplastic material used to create the weldseal may be provided by a thermoplastic film or coating on the inner surface of the container wall and/or on the seaiing disc.

As used herein, a paperboard packaging container is a packaging container wherein thecontainer body is formed from paperboard web material. The paperboard container maybe formed in any manner known in the art, e.g. by forming a container body by bendingthe paperboard web material into a tubular shape and longitudinally closing the tube byjoining overlapping or abutting side edges of the sheet material. The join between the side edges may be covered by a sealing strip.

As used herein, a paperboard web material is a material predominantly made fromcellulose fibers or paper fibers. The web material may be provided in the form of acontinuous web or may be provided as individual sheets of material. The paperboardmaterial may be a single ply or multi ply material and may be a laminate comprising one ormore layers of materials such as polymeric films and coatings, metal foil, etc. Thepolymeric films and coatings may include or consist of thermoplastic polymers. Thepaperboard materials as disclosed herein may also be referred to as cardboard or carton materials.

As used herein, the term “bulk solids” refers to a solid material. The bulk material may bedry or moist. The bulk solids may be in the form of particles, granules, grinds, plantfragments, short fibres, flakes, seeds, formed pieces of material such as pasta, etc.

The bulk solids which are suitable for packaging in the packaging containers as disclosedherein may be flowable, which means that a desired amount of the product may be pouredor scooped out of the packaging container, or in the form of discreet pieces of material allowing removal of only part of the content in the packaging container. 12 By a “pulverulent material” as used herein is implied any material in the form of particles,granules, grinds, plant fragments, short fibres, flakes, etc.

A partly or fully removable transport closure may be gastight or gas-permeable. A gastightmember may be manufactured from any material or material combination suitable forproviding a gastight sealing of a compartment delimited by the transport closure, such asaluminium foil, silicon-coated paper, plastic film, or laminates thereof. A gastight memberis advantageous when the bulk solids stored in the packaging container are sensitive to airand/or moisture, and it is desirable to avoid contact of the packaged bulk solids withambient air. According to the present disclosure a gastight transport closure is preferredas the purpose is to produce and maintained a controlled and stabilized pressure within the packaging container. in the assembled and filled packaging container which is disclosed herein, the peelable oropenable transport closure forms a cross-sectional seal between an inner compartment inthe container body and the container opening. The inner peelable or openable transportclosure is a transport and storage seal which is eventually broken or removed by an end user of the packaging container.

A packaging container having a volume of approximately 1l may be considered to be gas-tight if it provides an oxygen barrier of approximately 0.006 cc oxygen/24 h or less at23 °C and 50% relative humidity.

Optionally, the packaging container comprises a closure arrangement comprising a lid forclosing the upper body opening. The lid may be arranged to cooperate with an upper rimwhich is attached at the upper container body opening. The upper rim may be a singleplastic rim or a two-part rim construction arranged to reinforce and stabilize the uppercontainer body opening on a paperboard packaging container. The upper rim or a part of a two-part rim construction may be hingedly connected to the lid.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein: Fig. 1 illustrates a packaging container according to the present disclosure; 13 Fig. 2 shows an exploded view of a packaging container according to thepresent disclosure; Fig. 3 illustrates a perspective view of a bottom disc according to the presentdisclosure; Fig. 4 illustrates a perspective view of the bottom disc according to Fig. 3 withthe disc border flexed to form a flange; Fig. 5 illustrates a cross-section taken along the line V-V in Fig 4; Fig. 6 illustrates a perspective view of the bottom disc according to Fig, 4; Fig. 7 illustrates a perspective view of a bottom disc according to the presentdisclosure; Fig. 8 illustrates a cross-section taken along the line Vlll-Vlll in Fig. 7; Fig. 9 illustrates a perspective view of the bottom disc according to Fig. 7 DETAILED DESCRIPTION lt is to be understood that the drawings are schematic and that individual components, such as layers of materials are not necessarily drawn to scale. The paperboard sealingdiscs shown in the figures are provided as examples only and should not be consideredlimiting to the invention. Accordingly, the scope of invention is determined solely by the scope of the appended claims.

Figs. 1 and 2 illustrate a paperboard packaging container 1 for bulk solids according to thepresent disclosure. The particular shape of the container 1 shown in the figures should notbe considered limiting to the invention. Accordingly, a packaging container produced according to the invention may have any useful shape or size.

The packaging container 1 comprises a container body 2 having a container wall 3extending between an upper end 4 with an upper body opening 5' and a bottom end 6 witha bottom body opening 5”. The container wall 3 has an inner surface 7 facing towards aninner compartment 9 in the packaging container 1 and an outer surface 8 facing awayfrom the inner compartment 9. The container body 2 is made from paperboard material as defined herein.

The packaging container 1 furthermore comprises an inner partly or fully removabletransport closure 18, i.e. not being a sealing disc 10 as disclosed herein in the packaging container 1 disclosed in figs. 1 and 2, forming a cross-sectional seal between the inner 14 compartment 9 in the container body 2 and the upper body opening 5', as shown in fig. 2.The packaging container 1 also comprises a closure arrangement comprising a lid 16 anda sealing disc 10, in the form of a bottom disc, seaiing the bottom body opening 5", theseaiing disc 10 being defined by outer edges 30. As shown in fig. 2, the seaiing disc 10also comprises a seaiing disc border 11 surrounding a seaiing disc base portion 12. Theborder 11 is shaped before insertion and projects out of a main plane of the seaiing disc10 to form a flange 13 aligned with the inner surface 7 of the container wall 3. The flangeis sealed against the inner surface 7. The sealing disc 10 may be attached by welding,such as by high frequency welding, to the inner surface 7 of the container wall 3 to ensurea tight seal between the flange 13 of the seaiing disc 10 and the inner surface 7 of thecontainer wall 3. While the seaiing disc may be made from any suitable material such as paperboard, plastic or metal, paperboard seaiing discs may generally be preferred.

The seaiing disc 10 comprises distance elements 14 arranged side-by-side in the seaiingdisc border facing the inner surface 7 of the container wall 3. The distance elements 14have a height H in a direction perpendicular to the longitudinal direction of the containerwall 3. The illustrated distance elements 14 are elongated distance elements extendingfrom the seaiing disc inner folding edge 31 to the outer edges 30, forming air conveyingpassages 15 in the form of air conveying channels 15 between the distance elements 14.The air conveying channels 15 have a width of between 1 and 20 mm, which correspondsto the width between the adjacent distance elements 14, and the purpose of the airconveying channels 15 is to provide air passage to control the pressure level within theinner compartment 9 of the packaging container 1 during assembly of the packagingcontainer 1. The air passage thus extends from the seaiing disc inner folding edge 31 tothe outer edges 30, thus forming a channel out from the inner compartment 9 beforeattaching the flange 13 to the inner surface 7 of the container wall 3. After attachment ofthe flange 13 to the inner surface 7 of the container wall 3, the distance elements 14 arecompressed such that an air-tight seal is formed between the flange 13 and the innersurface of the container wall 3. The seaiing disc 10 shown in fig. 2 is, in addition to thedistance elements 14, provided with reinforcing elements 19 at the seaiing disc baseportion 12, which improves the stability of the seaiing disc 10. The reinforcing elements 19may be embossed lines and/or dotted embossed lines in the seaiing disc 10, alternatively,the reinforcing elements 19 may be reinforcing strips of material or reinforcing fold linesforming inwardly disposed ridges. As shown in fig. 2, the packaging container 1 may, furthermore, be provided with a reinforcement rim 20. The bottom reinforcement rim 20 may be joined to the inner surface 7 of the container wall 3 by welding such that a morereliably sift-proofjoin between the rim 20 and the container wall 3 can be achieved, thanwith an adhesive seal. ln figs. 1 and 2 the packaging container is furthermore provided with an upper reinforcingrim (not shown) which is attached, e.g. by welding, to the inner surface of the containerwall 3 at the upper body opening 5' and a frame structure 22, which may be mechanicallyconnected with the upper reinforcing rim. The frame structure 22 may then serve toprovide features such as a lid hinge. The frame structure 22 is in figs. 1 and 2 providedwith locking elements 23 for retaining the lid 16 in a closed position over the access opening.

The application of a bottom reinforcing rim 20 to the bottom end of the packagingcontainer, an upper reinforcing rim to the upper body opening 5” and a frame structure 22 is optional for the packaging container disclosed herein.

Fig. 3 shows a sealing disc 10, such as a bottom disc or a transport closure, in a flat andunfolded condition and provided with optional folding lines 21 for facilitated folding, suchas when the sealing disc 10 is inserted into the bottom body opening 5", or alternativelyinto the upper body opening 5”. The sealing disc 10 has a modified rectangular shape withcurved edge portions 25 with first and second longitudinal opposing side portions 26, 27and first and second transverse opposing side portions 28, 29 extending between thecurved edge portions 25. As illustrated in this figure, each of the curved edge portions 25are free from distance elements 14. The fact that the curved edge portions 25 are freefrom distance elements 14 improves the seai between fiange 13 and the inner surface 7as it prevents wrinkles to form adjacent to the distance elements 14 in the border whenfolding the outer edge portion 11 to form a fiange 13. This may otherwise impair the sealbetween the fiange 13 of the sealing disc 10 against the inner surface 7 of the container wall 3.

Fig. 4 shows the sealing disc 10, such as a bottom disc or a transport closure, when theborder 11 has been flexed to form a fiange 13, as during insertion into the packagingcontainer 1. The sealing disc border 11 have been flexed along the folding lines 21,forming a sealing disc inner folding edge 31, shown in fig. 3, and projects out of a main plane of the sealing disc 10 to form a fiange 13. The sealing disc 10 further comprises 16 distance elements 14 having a height H, and which protrude towards the inner surface 7 ofthe container wall 3 when the sealing disc has been introduced into either the bottom bodyopening 5" or alternatively into the upper body opening 5”. The distance elements 14extend from the sealing disc inner folding edge 31 to the outer edges 30 forming airconveying channels 15 between the distance elements 14. lt should however beunderstood that the distance elements 14 may also be in the form of dots and shorterdistance elements 14, as long as air conveying passages are formed between thedistance elements 14. The sealing disc 10 is additionally provided with reinforcingelements 19 in the sealing disc base portion 12, which further improves the stability of thesealing disc 10. The reinforcing elements 19 are embossed lines forming inwardlydisposed ridges. The distance elements 14 in this figure extend to the sealing disc innerfolding edge 31. However, the distance elements 14 may of course also be shorter andextend about 1 mm, or between from 1 to 3 mm from the sealing disc inner folding edge31. ln fig. 5 the height H of the distance elements 14, as measured from the inner surface of the sealing disc, is equal to or larger than the thickness T of the sealing disc 10.

Fig. 5 is a cross sectional view of the sealing disc 10 according to fig. 4 along the line V-V,wherein the height H, as measured from the inner surface of the sealing disc 10, of thedistance elements 14 is at least 0.005 mm. The air conveying channels have a width ofbetween 0.5 and 8 cm, or between 0.5 and 5 cm. This ensures that the air conveyingchannels 15 provided between the distance elements 14 will provide an air passage tocontrol the pressure level within the inner compartment of the packaging container duringassembly of the packaging container, and specifically during the final sealing step after the packaging container 1 has been filled with the bulk solids.

Fig. 6 illustrates the sealing disc 10 from figs. 4 and 5 shown from the side facing away from the inner compartment 9.

Fig. 7 illustrates a sealing disc 10 with first and second longitudinal opposing side portions26, 27 and first and second transverse opposing side portions 28, 29 extending betweencurved edge portions 25. The sealing disc 10 is provided with distance elements 14 on theinner surface extending continuously over the sealing disc base portion 14 and betweeneach of the opposing sealing disc side portion at the first and second longitudinal side portions 26, 27. The curved edge portions 25 are free from distance elements14. 17 Fig. 8 is a cross sectional view of the sealing disc 10 according to fig. 7 along the line Vlll-Vlll, wherein the height H, as measured from the inner surface of the sealing disc 10, ofthe distance elements 14 is at least 0.03 mm, such as from 0.03 to 3 mm. The airconveying channels have a width of between from 1 to 20 mm, or between from 3 to 10mm. This contributes to that the air conveying channels 15 provided between the distanceelements 14 provides an air passage to control the pressure level within the inner compartment of the packaging container.

Fig. 9 illustrates the sealing disc 10 according to fig. 7 shown from the side facing away from the inner compartment 9. lt is to be understood that the figures should not be seen as limiting to the configuration ofthe sealing disc. The sealing disc may thus for example be provided with more or fewerdistance elements, larger or smaller flange, no reinforcement elements in the base portion, or alternatively a different type of reinforcements in the base portion.

Claims

1. _ A paperboard sealing disc (10) for use in a paperboard packaging container (1) forbulk solids, said packaging container (1) comprising a container body (2) with anupper end (4) with an upper body opening (5') and a bottom end (6) with a bottombody opening (5”), a container wall (3) extending between said upper end (4) andsaid bottom end (6) in a longitudinal direction (L), said container wall (3) having aninner surface (7) facing towards an inner compartment (9) in said packagingcontainer (1) and an outer surface (8) facing away from said inner compartment(9), said sealing disc (10) being intended for sealing said upper body opening (5')or said bottom body opening (5”), said sealing disc (10) comprising a sealing discborder (11) surrounding a sealing disc base portion (12), wherein said border (11)is delimited from said disc base portion (12) by a sealing disc inner folding edge(31), said sealing disc border (11) being intended to be flexed at said inner foldingedge (31) to project out of a main plane of said sealing disc (10) and to be alignedwith and sealed to said inner surface (7) of said container wall (3), characterizedin that said sealing disc (10) comprises one or more distance e|ement(s) (14)being arranged in said sealing disc border (11), said distance element(s) (14) having a height (H), as measured from the surface of said sealing disc border (11). The sealing disc (10) according to claim 1, characterized in that said sealing disc(10) comprises two or more distance elements (14) arranged side-by-side in saidbottom disc border (11). The sealing disc (10) according to claim 2, characterized in that said distanceelements (14) are provided with a distance from each other of from 1 to 20 mm, as measured between each of the distance elements (14). The sealing disc (10) according to any one of claims 1 - 3, characterized in thatsaid distance element(s) (14) are provided at said sealing disc inner folding edge(31) or with a distance of no more than 1 mm from said sealing disc inner foldingedge (31). The sealing disc (10) according to any one of the preceding claims, characterizedin that said one or more distance element(s) (14), is/are elongated distanceelement(s) (14) having have a length (L) of 1 mm or more. 10. 11. 12. 13. 19 The seaiing disc (10) according to any one of the preceding claims, characterizedin that said height (H) of said distance elements (14) is at least 0.005 mm, such as from 0.005 mm to 3 mm. The seaiing disc (10) according to any one of the preceding claims, characterizedin that said seaiing disc (10) has a iongitudinal direction (y) and a transversedirection (x) perpendicularto said Iongitudinai direction (y), and first and secondlongitudinal opposing border (26, 27) extending in said Iongitudinai direction (y),and first and second transverse opposing border (28, 29) extending in saidtransverse direction (x), wherein said first and said second Iongitudinai opposingborder (26, 27) and said first and said second transverse opposing border (28, 29)extend between curved corner portions (25), said distance elements(14) extendingalong said first and second Iongitudinai opposing border (26, 27) in said transverse direction (x). The seaiing disc (10) according to claim 7, characterized in that said curved corner portions are free from said distance elements (14). The seaiing disc (10) according to any one of the preceding claims, characterizedin that said one or more elongated distance e|ement(s) (14) extend across saidseaiing disc (10). The seaiing disc (10) according to any one of the preceding claims, characterizedin that said distance e|ement(s) (14) comprises or consist of embossed dots or lines in said seaiing disc (10). The seaiing disc (10) according to any one of the preceding ciaims, characterizedin that said seaiing disc (10) comprises reinforcing elements provided in, andextending only within, said seaiing disc base portion (12). The seaiing disc (10) according to any of the preceding claims, characterized in that said seaiing disc (10) is a bottom disc. The seaiing disc (10) according to any one of claims 1-11, characterized in that said seaiing disc (10) is an inner partly or fully removable transport closure (10') 14. intend to form a cross-sectional seal between said inner compartment (9) in said container body (2) and said upper body opening (5'). A method of producing and filling a paperboard packaging container (1) with bulk solids (25), characterized in that the method comprises the steps of: a) C) d) forming a tubuiar container body (2) from a paperboard sheet (2”), saidcontainer body having an upper end (4) with an upper body opening (6') and abottom end (5) with a bottom body opening (6") and a container body wall (3)extending in a height direction (H) of said packaging container (1) betweensaid upper body opening (6') and said bottom body opening (6”), saidcontainer body wall (3) having an inner surface (7) and an outer surface (8), anupper end edge (12) and an bottom end edge (13); attaching an inner partly or fully removabie transport closure (18) to said innersurface (7) of said container body wall (3) and/or sealing said upper bodyopening (6') with a container lid (16) and; presenting said container body (2) to a filling station with said bottom bodyopening (6”) of said container body (2) directed upward in a vertical direction;filling bulk solids (25) into said container body (2) through said upwardlydirected bottom body opening (6"); closing said bottom body opening (6") by pressing a sealing disc (10) into saidbottom body opening (6”), the sealing disc (10) comprising a sealing discborder (11) surrounding a sealing disc base portion (12), said sealing discborder (11) being flexed towards the upper end (4) in the height direction (H),said sealing disc (10) comprising one or more distance e|ement(s) (14) beingarranged in an inner surface facing said container body wall (3), said distanceelements (14) having a height (H) in a direction perpendicular to saidlongitudinal direction (L) of said container wall (3), defining two or more airconveying passages (15) at each side of said one or more distance elements(14) and between said inner surface of said sealing disc border (11) and saidcontainer wall (3), and; attaching said flange (13) to said inner surface (7) of said container body wall (3)- 15. A method of producing and filling a paperboard packaging container (1) with bulk solids (25), characterized in that the method comprises the steps of: 16. 17. 21 forming a tubular container body (2) from a paperboard sheet (2'), saidcontainer body having an upper end (4) with an upper body opening (6') and abottom end (5) with a bottom body opening (6") and a container body wall (3)extending in a height direction (H) of said packaging container (1) betweensaid upper body opening (6') and said bottom body opening (6"), saidcontainer body wall (3) having an inner surface (7) and an outer surface (8), anupper end edge (12) and an bottom end edge (13); closing said bottom body opening (6”); presenting said container body (2) to a filling station with said upper bodyopening (6”) of said container body (2) directed upward in a vertical direction;filling bulk solids (25) into said container body (2) through said upwardlydirected upper body opening (6'); closing said upper body opening (6') by pressing a sealing disc (10) into saidupper body opening (6'), the sealing disc (10) comprising a sealing disc border(11) surrounding a sealing disc base portion (12), said sealing disc border (11)being flexed towards the upper end (4) in the height direction (H), said sealingdisc (10) comprising one or more distance e|ement(s) (14) being arranged insaid sealing disc border (11) on an inner surface facing said container bodywall (3), said distance elements (14) having a height (H) in a directionperpendicular to said longitudinal direction (L) of said container wall (3), withtwo or more air conveying passages (15) being defined on each side of saiddistance elements (14) and between said inner surface of said sealing discborder (11) and said container wall (3), and; attaching said flange (10”) to said inner surface (7) of said container body wall (3)- The method of producing and filling a paperboard packaging container (1) with bulk solids (25) according to claim 15, characterized in that said sealing disc (10) comprises two or more more distance elements (14) arranged side-by-side in said sealing disc border (11) and defining at least one air conveying passages (15) between said distance elements (14), said air conveying passage (15) between said distance elements (14) having a width of from 1 to 20 mm. The method of producing and filling a paperboard packaging container (1) with bulk solids (25) according to any one of claims 15-17, characterized in that said height 22 (H) of said distance elements (14) is at least 0.005 mm, such as from 0.005 mm to 3 mm, as measured from said inner surface of said seaiing disc border (11). 18. The method of producing and filling a paperboard packaging container (1) with bulksolids (25) according to any one of claims 15-17, characterized in that said seaiingdisc (10) is pre-formed and already flexed and shaped to a flange (13) before being pressed into the body upper or bottom opening (6',6”).