Composite paperboard container for bulk solids and method for producing the same

Abstract

This disclosure relates to a composite paperboard container (1) for bulk solids, the composite paperboard container comprising a tubular body (2) closed at its bottom end (3) above a bottom opening (4) opposite to a top opening (5). The composite container includes an edge (9) surrounding the top and / or bottom openings. The edge is attached to an end portion (10) of the tubular body via a first connecting portion (11). The edge is a molded edge comprising pulp fibers. The edge is connected to the tubular body via a first adhesive layer (14) at each 10 mm perimeter of the container opening at the end portion of the tubular body. t p b The amounts, starting from 0.1 mg, include or consist of thermoplastic binders. This disclosure also relates to a method for producing composite paperboard containers.

Description

Technical Field

[0001] This disclosure relates to a composite paperboard container and a method for producing the composite paperboard container. Background Technology

[0002] In the field of single-use containers used for products such as infant formula, tobacco, and detergents, there is an ongoing need to reduce the carbon footprint of these products by minimizing resource use and making the containers recyclable. The single-use containers referred to herein are composite containers with a tubular body made of a laminated sheet comprising a cardboard layer, i.e., a layer primarily made of cellulose fibers. For some containers, the upper and lower edges include plastic edging pieces attached to the edges of the packaging container. This provides the packaging container with an appealing and neat appearance, and the top or bottom of the container can also be more abrasion-resistant. To provide containers without plastic parts, the top and / or bottom portions of the container can alternatively be made from folded-in ends of the tubular body. However, the appearance of such packaging containers is slightly less attractive and less abrasion-resistant at the bottom.

[0003] Traditionally, paper-based materials have been considered unsuitable for manufacturing lids and rims of cardboard containers due to their perceived lower shape stability and fragility compared to plastic parts. It is also difficult to achieve a strong and tight attachment between these components and the body of the cardboard container, as well as a tight seal between the rims and the lid.

[0004] Therefore, there is a need for further packaging for sensitive goods such as food that offers improved recyclability without sacrificing the durability of the packaged goods or the safety of the packaging. Summary of the Invention

[0005] The above-mentioned objectives can be achieved by the method for manufacturing composite paperboard containers according to the following embodiments, and by utilizing composite paperboard containers according to the following embodiments. Further advantages and advantageous features of the present invention are disclosed in the following description.

[0006] According to one embodiment, a composite paperboard container for bulk solids includes a tubular body closed at its bottom end and at a bottom opening opposite to a top opening at its top end. The tubular body has an inner surface facing the interior of the tubular body and an outer surface facing away from the interior of the tubular body. The tubular body extends longitudinally between the bottom end and the top end. The composite paperboard container includes an edge member surrounding the top opening and / or the bottom opening, the top opening having a top opening periphery and the bottom opening having a bottom opening periphery. The edge member extends along the tubular body via a first connecting portion. An end edge is attached to the end portion of the tubular body, the tubular body being made of a laminated sheet including a carton base layer, characterized in that the edge member is a molded edge member comprising fibers, the fibers being pulp fibers, the edge member comprising 100% pulp fibers, and formed by compression molding in a molding tool, between a female molding tool component and a male molding tool component, the edge member being connected to the tubular body by a first adhesive layer comprising a thermoplastic adhesive and disposed in a first gap between the first connecting portion of the edge member and the end portion of the tubular body, the first adhesive layer comprising or consisting of the thermoplastic adhesive in an amount starting from 0.1 mg per millimeter around the container opening at the end portion of the tubular body, wherein the edge member includes a square-edged U-shaped track portion, the track portion including a first sidewall section and a second sidewall section and a bottom section facing the end edge of the tubular body and connecting the first sidewall section and the second sidewall section.

[0007] According to one embodiment, a method for producing composite paperboard containers for bulk solids includes the following steps: a) bending a paperboard laminate sheet including a paperboard base layer into a tube having a longitudinal direction, closing the tube in the longitudinal direction by engaging overlapping or adjacent side edges of the paperboard laminate sheet to form a tubular body, the tubular body having an inner surface facing the interior of the tubular body and an outer surface facing away from the interior of the tubular body; b) giving the tubular body a predetermined cross-sectional shape; c) closing the tubular body at its bottom end, at a container bottom opening opposite to a container top opening at the top end of the tubular body; d) ... Pulp fibers are provided into a molding tool, the molding tool including a female molding tool component and a male molding tool component, and the pulp fibers are pressed and molded between the female molding tool component and the male molding tool component to form a three-dimensionally shaped edge member comprising 100% pulp fibers, the edge member including a first connecting portion having a distal edge; e) a first adhesive layer comprising a thermoplastic adhesive is provided to the first connecting portion of the edge member, or alternatively or additionally provided along the end edge of the tubular body to the end portion of the tubular body, the amount of the thermoplastic adhesive being 0.1 per millimeter around the container opening at the end portion. mg; and f) providing the edge member to the end portion to adhesively attach the edge member to the tubular body, wherein the edge member formed in step d) includes a U-shaped track portion with square sides, the track portion including a first sidewall section and a second sidewall section and a bottom section facing the end edge of the tubular body, and wherein step e) includes arranging the edge member such that the bottom section faces the end edge of the tubular body.

[0008] According to a first aspect, this disclosure relates to a composite paperboard container for bulk solids. The composite paperboard container includes a tubular body that is closed at its bottom end above a container bottom opening opposite to a container top opening located at the top end of the tubular body. The tubular body has an inner surface facing the interior of the tubular body and an outer surface facing away from the interior of the tubular body. The tubular body extends longitudinally between its bottom and top ends. The composite container includes an edge member surrounding the container top opening and / or bottom opening, the container top opening having a top opening periphery and the container bottom opening having a bottom opening periphery. The edge member is attached to an end portion of the tubular body along an end edge of the tubular body via a first connecting portion of the edge member. The tubular body is made of a laminated sheet comprising a carton base layer. The edge member is a molded edge member comprising pulp fibers (such as cork pulp fibers). The edge member is connected to the tubular body via a first adhesive layer comprising a thermoplastic adhesive and disposed in a first gap between the first connecting portion of the edge member and the end portion of the tubular body. The first adhesive layer comprises or consists of a thermoplastic adhesive in an amount starting from 0.1 mg per millimeter around the container opening at the end portion of the tubular body.

[0009] The first adhesive layer may comprise or consist of a thermoplastic adhesive in an amount ranging from 0.1 mg to 10 mg per millimeter of the container opening perimeter at the end portion of the tubular body. Preferably, the first adhesive layer comprises or consists of a thermoplastic adhesive in an amount ranging from 0.5 mg to 5 mg per millimeter of the container opening perimeter at the end portion of the tubular body. The first adhesive layer may also comprise or consist of a thermoplastic adhesive in an amount ranging from 1 mg to 5 mg per millimeter of the container opening perimeter at the end portion of the tubular body.

[0010] The edge is a molded edge comprising pulp fibers, which can be composed of 95% to 100% pulp fibers such as cork pulp fibers, and optionally 98% to 100% pulp fibers. Examples of such materials developed for molding applications (such as molded trays and blister packs, molded or embossed boxes, etc.) include those produced by Billerud Gruvӧn and marketed as Billerud FibreForm. ® Sales. A similar material is the Advantage Formable paper offered by Mondi.

[0011] There is a desire to provide packaging for sensitive goods such as food products that offers improved recyclability without sacrificing the durability or security of the packaged goods. However, because the edge piece is a molded edge piece comprising pulp fibers, the structure is less flexible and has a more irregular surface compared to conventional plastic edge pieces. This reduces the adhesion between the edge piece and the tubular cardboard body, thereby reducing the rigidity of the container. Consequently, the durability or security of the packaged goods is reduced due to the risk of small insects (such as pharaoh ants) passing through the space between the tubular body and the edge piece. However, the inventors have unexpectedly discovered that satisfactory sealing can be achieved by increasing the amount of thermoplastic adhesive to a level starting from 0.1 mg per millimeter around the container opening to which the edge piece is attached, thus allowing for the packaging of sensitive goods such as food.

[0012] The end portion of the tubular body can be at the top opening of the container or at the bottom opening of the container.

[0013] The edge member can be attached to the inner or outer surface of the tubular body via a first connecting portion. The first connecting portion is a circumferential connection extending around the entire periphery of the tubular body. The first connecting portion is attached to the tubular body along its entire end portion. To provide enhanced attachment and sealing between the edge member and the tubular body, the tubular body may have a thermoplastic layer, such as a polyethylene or polypropylene layer, provided on the surface facing the first connecting portion—such as on the inner and / or outer surfaces of the tubular body. Alternatively or additionally, the edge member may have a thermoplastic layer provided on the surface facing the tubular body. The thermoplastic layer provides a more regular surface to the edge member, thereby enhancing sealing and improving the durability or packaging security of the packaged goods.

[0014] The first connecting portion, serving as the first circumferential portion of the edge member, may have a first distal edge, and the first distal edge of the first connecting portion may be located at a distance from the end edge of the tubular body, starting from 4 mm, optionally ranging from 4 mm to 50 mm, and preferably ranging from 5 mm to 40 mm. The first connecting portion of the edge member may be a longitudinally extending circumferential collar facing the inner or outer surface of the tubular body. Since the edge member is a molded edge member comprising pulp fibers, this structure exhibits lower flexibility and stability compared to conventional plastic edge members. It has been found that having a first connecting portion located at a distance from the end edge starting from 4 mm, optionally ranging from 4 mm to 50 mm, provides enhanced shape stability to the edge member by supporting the most vulnerable part of the edge member—i.e., the connecting portion or multiple connecting portions—through the wall of the tubular body.

[0015] The circumferential region of the first connecting portion of the tubular body facing the edge member may be covered by a first adhesive layer, the circumferential region extending at least 4 mm, optionally at least 10 mm, from the end edge of the tubular body toward the opposite end edge of the tubular body when viewed in the longitudinal direction. This can provide structural support for the first connecting portion of the edge member.

[0016] The first connecting portion may face the inner surface of the tubular body, and the edge member may include a second connecting portion facing the outer surface of the tubular body. The edge member may also be connected to the tubular body via a second adhesive layer applied to the outer surface of the tubular body, the second adhesive layer comprising a thermoplastic adhesive or composed of a thermoplastic binder, and disposed in a second gap between the second connecting portion of the edge member and an end portion on the outer surface of the tubular body. Because the adhesive layer is disposed in the first gap between the first connecting portion and the inner surface and in the second gap between the second connecting portion and the tubular body, improved sealing and enhanced stability of the connection between the edge member and the tubular body can be achieved.

[0017] The second adhesive layer can be arranged in the second gap at an amount starting from 0.1 mg per millimeter around the container opening at the end portion of the tubular body.

[0018] The second adhesive layer may comprise or consist of a thermoplastic adhesive in an amount ranging from 0.1 mg to 10 mg per millimeter of the container opening perimeter at the end portion of the tubular body. Preferably, the second adhesive layer comprises or consists of a thermoplastic adhesive in an amount ranging from 0.5 mg to 5 mg per millimeter of the container opening perimeter at the end portion of the tubular body. The second adhesive layer may also comprise or consist of a thermoplastic adhesive in an amount ranging from 1 mg to 5 mg per millimeter of the container opening perimeter at the end portion of the tubular body.

[0019] The second connecting portion of the edge member may have a first distal edge, and the first distal edge of the connecting portion may be located at a distance from the end edge of the tubular body, the distance being in the range of 4 mm to 50 mm, optionally in the range of 5 mm to 40 mm.

[0020] The rim may surround the top opening of the container and be part of the lid component, which includes an rim and a lid portion molded together, wherein one or more hinge portions connect the rim to the lid portion.

[0021] The edge member may be an inner edge member, and the packaging container may additionally include a lid member comprising an outer edge portion and a lid portion. The outer edge member may include fibers and may be molded integrally with the outer edge portion, wherein the outer edge portion is connected to the lid portion via a hinge portion, and the outer edge member may be connected to the inner edge member.

[0022] Composite cardboard containers may be free of plastic components, such as plastic edge components, lid components, or bottom components. Plastic components refer to individual parts, not layers within the cardboard laminate. Such composite containers can be recycled without separating the plastic components from the cardboard container body.

[0023] The density of the edge components can be 0.2 kg / dm³. 3 Up to 1.5 kg / dm 3 Within the range, optionally within 0.2 kg / dm 3 Up to 1kg / dm 3 Within the range, optionally within 0.4 kg / dm 3 Up to 0.8 kg / dm 3 Within the scope of this disclosure. The edge members according to this disclosure are molded edge members, and therefore need to have structural durability, preferably similar to the structural durability of plastic edge members. For edge components to be connected to additional edge portions—such as inner edge components and outer edge components—these edge components need to have a certain degree of flexibility and be structurally stable.

[0024] The edge member may include a U-shaped or square-sided U-shaped track portion, which includes a first sidewall section, a second sidewall section, and a bottom section facing the end edge of the tubular body and connecting the first and second sidewall sections. The first sidewall section may correspond to a first connecting portion, or the first connecting portion may include the first sidewall section. The draft angle between the bottom section and the first sidewall section may be in the range of 0 to 10 degrees, optionally in the range of 0 to 5 degrees, which facilitates a tight fit between the edge member and the end portion of the tubular body along the entire first sidewall section.

[0025] The distance between the first sidewall section and the second sidewall section can vary by less than 3 mm along the entire length of the first and second sidewall sections. This facilitates a tight fit between the track portion of the edge piece and the end portion of the tubular body, stabilizes the edge piece and the tubular body at the end portion, and improves the durability of the packaged goods and the security of the packaging.

[0026] The edge member may include an L-shaped connecting portion comprising a first sidewall section and a bottom section facing the end edge of the tubular body. The first sidewall section may correspond to the first connecting portion, or the first connecting portion may include the first sidewall section. The draft angle between the bottom section and the first sidewall section may be in the range of 0 to 10 degrees, optionally in the range of 0 to 5 degrees. This facilitates a tight fit between the L-shaped connecting portion and the end portion of the tubular body, thereby improving the durability and packaging security of the packaged goods.

[0027] The distance between the bottom section and the distal edge of the connecting portion can start from 3 mm, and optionally range from 7 mm to 30 mm. This connecting portion helps improve structural stability and extend storage stability.

[0028] The first connecting portion may be provided with distance elements, such as ribs extending in the longitudinal direction of the tubular body, facing the tubular body, such as, for example, the inner surface of the tubular body. The first connecting portion may be provided with three or more distance elements, such as five or more, or ten or more distance elements, arranged in parallel when viewed in the circumferential direction of the tubular body. When the edge piece is applied to the end portion of the tubular body, the distance elements provide a channel for the adhesive and provide a distance to the tubular body, thereby preventing the adhesive from being scraped off from the first connecting portion / end portion of the tubular body when the edge piece is applied, and thus contributing to uniform application of the adhesive. In this case, the draft angle of the first connecting portion is measured at the location between the distance elements.

[0029] The first connecting portion may include a first sidewall segment and a guide sidewall segment, the guide sidewall segment extending from the first sidewall segment. The guide sidewall segment is the segment that is further from the tubular body than the first sidewall segment. The guide sidewall segment may be an inclined wall segment, the distance of which increases when viewed from the end edge of the tubular body along the longitudinal direction of the tubular body.

[0030] For edge components with L-shaped, U-shaped, or square U-shaped cross-sections, the guide sidewall section can be an inclined wall section, the distance from which to the tubular body increases when viewed from the end edge of the tubular body along its longitudinal direction. The guide wall section can have a draft angle from 2 degrees to 30 degrees. The draft angle of the guide wall section can be greater than that of the first sidewall section.

[0031] In step d), the first connecting portion may be provided with a distance element, such as a rib extending in the longitudinal direction of the tubular body, the distance element facing the tubular body, such as, for example, the inner surface of the tubular body.

[0032] Because the edge piece is made of pulp fibers, this structure is more fragile and less flexible than a plastic edge piece, and also generates greater friction between the edge piece and the tubular cardboard body. To reduce the risk of damaging the edge piece or edge portion when applying adhesive to the first connection, the edge piece may include a guide sidewall section extending from the first sidewall section. Additionally, this helps to properly apply adhesive to the first connection portion by enhancing the passageway for the nozzle used to apply the adhesive. This is also an advantage when the edge piece is attached to the tubular body. This is particularly advantageous when the edge piece includes a U-shaped or square-sided U-shaped track portion into which the end portion of the tubular body is inserted. Due to the fact that the edge piece comprises pulp fibers, an increased amount of adhesive needs to be applied between the edge piece and the tubular body to ensure that the adhesive fully fills the gap between the edge piece and the track sidewall. The guide portion can also serve as a reservoir for adhesive to be extruded from the gap, thereby protecting the interior or exterior surfaces of the container from adhesive contamination.

[0033] According to a second aspect, this disclosure relates to a method for producing a composite paperboard container for bulk solids according to any of the foregoing embodiments, the method comprising the following steps:

[0034] a) A paperboard laminate sheet comprising a paperboard base layer and a thermoplastic weld layer is bent into a tube having a longitudinal direction and a radial direction perpendicular to the longitudinal direction, and the tube is closed longitudinally by joining the overlapping or adjacent side edges of the paperboard material to form a tubular body having an inner surface facing the interior of the tubular body and an outer surface facing away from the interior of the tubular body.

[0035] b) To give the tube a predetermined cross-sectional shape;

[0036] c) The tubular body is closed at the bottom, above the bottom opening of the container opposite to the top opening of the container at the top of the tubular body;

[0037] d) Pulp fibers, such as cork fibers, are fed into a molding tool to form an edge member comprising a three-dimensional shape of fibers, the fibers being pulp fibers, the edge member including a connecting portion having a distal edge;

[0038] e) A first adhesive layer comprising a thermoplastic adhesive is provided along the end edge of the tubular body to the first connecting portion of the edge member and / or the end portion of the tubular body, the amount of the thermoplastic adhesive being 0.1 mg per millimeter of the container opening perimeter at the end portion; and

[0039] f) Provide the edge piece to the end portion, thereby adhesively attaching the edge piece to the tubular body.

[0040] Step d) of forming the edge member may include forming an edge member having a second connecting portion, and wherein step f) may include providing a first adhesive layer on an end portion of the inner surface of the tubular body, and further providing a second adhesive layer comprising a thermoplastic adhesive on an end portion of the outer surface of the tubular body.

[0041] In step d), the second adhesive layer may be arranged in the second gap in an amount starting from 0.1 mg per millimeter around the container opening at the end portion of the tubular body.

[0042] Furthermore, it should be understood that steps e) and f) can be performed in combination such that the edge piece is attached to the end portion and a first adhesive layer comprising a thermoplastic adhesive is injected at an amount starting from 0.1 mg per millimeter around the container opening at the end portion into the gap between the end portion of the tubular body and the first connecting portion of the edge piece.

[0043] The density of the edge components can be 0.2 kg / dm³. 3 Up to 1.5 kg / dm 3 Within the range, optionally within 0.2 kg / dm 3 Up to 1kg / dm 3 Within the range, optionally within 0.4 kg / dm 3 Up to 0.8 kg / dm 3 Within the range.

[0044] The edge member formed in step d) may include a U-shaped or square-sided U-shaped track portion, the track portion including a first sidewall section and a second sidewall section and a bottom section facing the end edge of the tubular body, and wherein step e) may include arranging the edge member such that the bottom section faces the end edge of the tubular body.

[0045] The draft angle between the bottom section and the first sidewall section can be in the range of 0 to 10 degrees, such as 0 to 5 degrees.

[0046] The distance between the first sidewall segment and the second sidewall segment can vary by less than 3 mm along the entire first and second sidewall segments.

[0047] The edge member formed in step d) may include an L-shaped connecting portion, which includes a first sidewall section and a bottom section facing the end edge of the tubular body, and wherein the draft angle between the bottom section and the first sidewall section may be in the range of 0 to 10 degrees, such as in the range of 0 to 10 degrees, and optionally in the range of 0 to 5 degrees.

[0048] For the edge member formed in step d), the first connecting portion may include a guide sidewall section extending from the first wall section of the first connecting portion, wherein when the edge member is applied, the distance from the guide sidewall section to the tubular body is greater than the distance from the first wall section to the tubular body.

[0049] The guide sidewall section can be an inclined wall section, the distance of which increases when viewed from the end edge of the tubular body along its longitudinal direction. The guide wall section can have a draft angle of 2 to 30 degrees when viewed from the bottom section. The draft angle of the guide wall section can be greater than that of the first sidewall section.

[0050] In step d), the first connecting portion may be provided with a distance element, such as a rib extending in the longitudinal direction of the tubular body, the distance element facing the tubular body, such as, for example, the inner surface of the tubular body. When the edge piece is applied to the end portion of the tubular body, the distance element provides a channel for the adhesive and provides a distance to the tubular body, thereby preventing the adhesive from being scraped off from the end portion of the first connecting portion / tubular body when the edge piece is applied, and thus facilitating uniform application of the adhesive.

[0051] The cross-sectional shape of the tubular body can be a modified rectangular shape with rounded corners. It should be understood that the tubular body can have any useful cross-sectional shape, such as a circle, an ellipse, or any polygon or modified polygon such as a triangle, a square, a pentagon, etc. Attached Figure Description

[0052] The invention will be further explained below by way of non-limiting examples and with reference to the accompanying drawings, wherein:

[0053] Figure 1 A composite paperboard container according to the present invention is shown;

[0054] Figure 2 The paperboard blank is shown;

[0055] Figure 3 This illustrates folding a cardboard blank into a tubular body;

[0056] Figure 4-5 The diagram shows a cardboard tray being inserted into a tubular body to form the bottom of the container.

[0057] Figure 6 This demonstrates the use of molded pulp fibers to form the edge and cover components;

[0058] Figures 7A-7C The molded edges and cover components are shown;

[0059] Figure 8 The application of adhesive to the edge piece is shown; and

[0060] Figure 9 The illustration shows an edge piece attached to a tubular body, thereby forming a composite paperboard container prepared by the method according to the present disclosure. Detailed Implementation

[0061] It should be understood that the accompanying drawings are schematic and individual components such as material layers and container parts are not necessarily drawn to scale.

[0062] The steps in the composite paperboard container and the method of forming the composite paperboard container shown in the figures are provided as examples only and should not be considered as limiting the invention. Therefore, the scope of the invention is determined only by the scope of the appended claims.

[0063] Figure 1 A composite paperboard container 1 for bulk solids is shown. The composite paperboard container 1 includes a tubular body 2, which is closed at a bottom end 3 above a bottom opening 4 opposite to a top opening 5 at a top end 6 of the tubular body 2. The tubular body 2 has an inner surface 7 facing the interior of the tubular body 2 and an outer surface 8 facing away from the interior of the tubular body 2. The tubular body 2 extends in a longitudinal direction L between the bottom end 3 and the top end 6. The tubular body is made of a laminated sheet comprising a carton base layer and a thermoplastic layer 14 on the inner surface 7. The composite container 1 includes a rim 9 surrounding the top opening 5 of the container. The rim 9 is a molded rim 9 as disclosed herein, comprising pulp fibers, such as cork pulp fibers. The rim 9 is an rim and cap part 9 and includes an rim portion 9a and a cap portion 9b. The rim portion 9a and the cap portion 9b are molded integrally. Edge portion 9a is connected to cover portion 9b via two hinge portions 9c. Edge member 9 is connected to tubular body 2 via a first adhesive layer 14 disposed in a first gap between first connecting portion 11 of edge member 9 and end portion 10 of tubular body 2. First connecting portion 11 faces inner surface 7 of tubular body 2.

[0064] The container top opening 5 has a top opening perimeter p t And the bottom opening 4 of the container has a bottom opening perimeter p b The edge portion 9a of the edge member 9 is attached to the end portion 10 of the tubular body 2 along the end edge 12 of the tubular body 2 via the first connecting portion 11 of the edge portion 9a. The tubular body 2 is made of a laminated sheet, which includes a carton base layer and a thermoplastic layer 19 disposed on the inner surface 7.

[0065] The first adhesive layer 14 is applied at the end portion 10 of the top 6 of the tubular body 2, at a distance of p per millimeter around the container opening. tAmounts starting from 0.1 mg include or consist of thermoplastic adhesives. If the edge piece is a bottom edge piece, the first adhesive layer is applied at a rate of p per millimeter around the container opening at the end portion 10 of the bottom end 3 of the tubular body 2. b The amount of 0.1 mg includes or is composed of thermoplastic binders. Figure 1 In the composite packaging container 1, the periphery of the top opening of the container is p t p around the bottom opening of the container b same.

[0066] Composite cardboard container 1 has no plastic parts—such as plastic edge parts, lid parts, or bottom parts.

[0067] As shown in the cross-sectional view, the edge portion 9a includes a U-shaped track portion 13, which includes a first sidewall section 13a, a second sidewall section 13b, and a bottom section 13c facing the end edge 12 of the tubular body 2. The connecting portion 11 of the edge portion 9a includes the first sidewall section 13a.

[0068] Figures 2 to 9 A method for producing composite paperboard containers 1 for bulk solids is shown. Figure 2 A cardboard laminate sheet 2" including a carton base layer is shown. The laminate sheet 2" has opposing side edges 16, 17. Figure 3 The first step a) is shown, in which a cardboard laminate sheet 2” is bent into a tube 2’ having a longitudinal direction L, and the tube 2’ is closed in the longitudinal direction L by joining adjacent side edges 16, 17 of the cardboard material 2”, thereby forming a tubular body 2. The joint between the side edges may be covered by a sealing strip. Alternatively, the side edges 16, 17 may be joined as overlapping side edges. The formed tubular body 2 has an inner surface 7 facing the interior of the tubular body 2 and an outer surface 8 facing away from the interior of the tubular body 2. A thermoplastic layer 19 is provided on the inner surface 7. The tube is formed to have a predetermined cross-section. In the example shown in the figure, the cross-sectional shape is a modified rectangular shape with rounded corners. It should be understood that the tubular body can have any useful cross-sectional shape, such as a circle, an ellipse, or any polygon or modified polygon such as a triangle, a square, a pentagon, etc.

[0069] Figure 4 and Figure 5The step c) is shown: closing the tubular body 2 at the bottom 3, above the container bottom opening 4 opposite to the container top opening 5 at the top 6 of the tubular body 2. The bottom opening 4 is closed by pressing a cardboard base 18 into the tube at the bottom 3. The base 18 has an outer peripheral flange 18a bent toward the bottom 3 in the longitudinal direction L. The bent outer peripheral flange 18a can be attached to the inner surface 7 of the tubular body 2, for example, by welding. The cardboard base 18 can be composed of a laminated sheet including a carton base layer and a thermoplastic welded layer. Alternatively or additionally, the tubular body 2 can have a thermoplastic welded layer provided on the inner surface 7. The thermoplastic welded layer can include metal powder, can be a metallized thermoplastic layer, or the laminated sheet can contain a metal foil such as aluminum foil.

[0070] Figure 6 The steps for forming the molded edge member 9 are shown. The molded edge member is formed by providing cork pulp fibers, such as slurry, in a molding tool 15. The molding tool 15 includes a female molding tool part 15a and a mating male molding tool part 15b, and the pulp fibers are pressed between the female molding tool part 15a and the male molding tool part 15b to form the edge member 9, which includes the three-dimensional shape of the pulp fibers.

[0071] Figures 7A-7C A rim and cover component is shown, comprising an rim portion 9a and a cover portion 9b molded integrally and interconnected by two hinge portions 9c. As seen in the cross-sectional view, the rim portion 9a has a U-shaped track portion 13, which includes opposing first sidewall sections 13a and second sidewall sections 13b, and a bottom section 13c for facing the end edge 12 of the tubular body 2. A first connecting portion 11 of the rim portion 9a includes the first sidewall section 13a and a guide sidewall section 13d, which extends in the longitudinal direction of the tubular body when the rim portion 9b is applied to the end edge of the tubular body. The draft angle α between the bottom section 13c and the first sidewall section 13a is in the range of 0 to 10 degrees, and the draft angle β between the bottom section 13c and the guide wall section 13d is in the range of 2 to 30 degrees. The draft angle of the guide wall section 13d is greater than that of the first side wall section 13a.

[0072] The first sidewall section 13a is provided with a distance element 20, such as a rib extending in the longitudinal direction L of the tubular body when the edge member is applied to the tubular body.

[0073] Figure 8The steps of applying a first adhesive layer 14, comprising a thermoplastic adhesive, to a first connecting portion 11 (which also corresponds to the first sidewall section 13a in this figure) are shown. The first adhesive layer 14 is applied around the entire periphery of the first connecting portion 11 of the edge member, which, when applied to the tubular body, extends around the entire periphery of the end portion of the tubular body.

[0074] Figure 9 The final step of attaching the edge member 9, including the edge portion 9a and the cover portion 9b, to the end portion 10 of the tubular body 2 is shown. The adhesive layer 14 is arranged facing the inner surface 7 of the tubular body 2.

Claims

1. A composite paperboard container (1) for bulk solids, the composite paperboard container (1) comprising a tubular body (2) closed at a bottom end (3) and at a bottom opening (4) opposite to a top opening (5) at a top end (6) of the tubular body (2), the tubular body (2) having an inner surface (7) facing the interior of the tubular body (2) and an outer surface (8) facing away from the interior of the tubular body (2), the tubular body (2) extending longitudinally (L) between the bottom end (3) and the top end (6), the composite paperboard container (1) comprising an edge member (9) surrounding the top opening (5) and / or the bottom opening (4), the top opening (5) having a top opening periphery (p t And the bottom opening (4) of the container has a bottom opening perimeter (p) b The edge member (9) is attached to the end portion (10) of the tubular body (2) along the end edge (12) of the tubular body (2) via the first connecting portion (11) of the edge member (9), the tubular body (2) being made of a laminated sheet including a carton base layer, characterized in that, The edge member (9) is a molded edge member (9) comprising fibers, the fibers being pulp fibers, the edge member comprising 100% pulp fibers, and formed by compression molding in a molding tool (15) between a female molding tool component (15a) and a male molding tool component (15b). The edge member (9) is connected to the tubular body (2) by a first adhesive layer (14), the first adhesive layer (14) comprising a thermoplastic adhesive and disposed in a first gap between the first connecting portion (11) of the edge member (9) and the end portion (10) of the tubular body (2). The first adhesive layer (14) comprises or is composed of the thermoplastic adhesive, the amount of the thermoplastic adhesive being per millimeter around the top opening at the end portion (10) of the tubular body (2). t ) and the area around the bottom opening (p b Starting from 0.1 mg, The edge member (9) includes a U-shaped track portion (13) with square edges. The track portion includes a first sidewall section (13a) and a second sidewall section (13b), as well as a bottom section (13c) that faces the end edge (12) of the tubular body (2) and connects the first sidewall section (13a) and the second sidewall section (13b). The draft angle (α) between the bottom section (13c) and the first sidewall section (13a) is in the range of 0 degrees to 10 degrees.

2. The composite paperboard container (1) according to claim 1, wherein, The first connecting portion (11) of the edge member (9) has a first distal edge (11a), and the first distal edge (11a) of the first connecting portion (11) is located at a distance (d) from the end edge (12) of the tubular body, the distance being in the range of 5 mm to 50 mm.

3. The composite paperboard container (1) according to claim 2, wherein, The first adhesive layer (14) covers the first connecting portion (11) of the tubular body (2) facing the edge member (9) and the circumferential region extending at least 4 mm from the end edge (12) of the tubular body (2) toward the opposite end edge.

4. The composite paperboard container (1) according to any one of claims 1 to 3, wherein, The first connecting portion (11) faces the inner surface (7) of the tubular body (2), and the edge member (9) includes a second connecting portion facing the outer surface (8) of the tubular body (2). The edge member (9) is also connected to the tubular body (2) by a second adhesive layer applied to the outer surface (8) of the tubular body (2). The second adhesive layer comprises or is composed of thermoplastic adhesive. The second adhesive layer is disposed in a second gap between the second connecting portion of the edge member (9) and the end portion (10) on the outer surface (8) of the tubular body (2).

5. The composite paperboard container (1) according to any one of claims 1-3, wherein, The edge member (9) surrounds the top opening (5) of the container and is an edge member including an edge portion (9a) and a lid portion (9b), wherein the edge portion (9a) and the lid portion (9b) are molded integrally, and the edge portion (9a) is connected to the lid portion (9b) via a hinge portion (9c).

6. The composite paperboard container (1) according to any one of claims 1-3, wherein, The composite cardboard container (1) does not contain plastic edge parts, lid parts or bottom parts.

7. The composite paperboard container (1) according to any one of claims 1-3, wherein, The density of the edge member (9) is 0.2 kg / dm³. 3 Up to 1.5 kg / dm 3 Within the range.

8. The composite paperboard container (1) according to any one of claims 1-3, wherein, The first connecting portion (11) is provided with a distance element (20), which faces the tubular body (2).

9. The composite paperboard container (1) according to any one of claims 1-3, wherein, The first connecting portion (11) includes a first sidewall section (13a) and a guide sidewall section (13d), the guide sidewall section (13d) extending from the first sidewall section (13a) and having a greater distance to the tubular body (2) than the first sidewall section (13a).

10. The composite paperboard container (1) according to claim 1, wherein, The edge element (9) is a molded edge element (9) comprising cork pulp fibers.

11. The composite paperboard container (1) according to claim 2, wherein, The distance (d) is in the range of 5 mm to 40 mm.

12. The composite paperboard container (1) according to claim 3, wherein, The circumferential region of the tubular body (2) facing the first connecting portion (11) of the edge member (9) and extending at least 10 mm from the end edge (12) of the tubular body (2) toward the opposite end edge is covered by the first adhesive layer (14).

13. The composite paperboard container (1) according to claim 6, wherein, The composite cardboard container (1) does not contain any plastic parts.

14. The composite paperboard container (1) according to claim 7, wherein, The density of the edge member (9) is 0.2 kg / dm³. 3 Up to 1 kg / dm 3 Within the range.

15. The composite paperboard container (1) according to claim 14, wherein, The density of the edge member (9) is 0.4 kg / dm³. 3 Up to 0.8 kg / dm 3 Within the range.

16. The composite paperboard container (1) according to claim 1, wherein, The draft angle (α) between the bottom section (13c) and the first sidewall section (13a) is in the range of 0 to 5 degrees.

17. The composite paperboard container (1) according to claim 8, wherein, The distance element (20) is a rib that extends in the longitudinal direction (L).

18. A method for producing a composite paperboard container (1) for bulk solids according to any one of the preceding claims, the method comprising the steps of: a) A paperboard laminate sheet (2") including a paperboard base layer is bent into a tube (2') having a longitudinal direction (L), and the tube (2') is closed in the longitudinal direction (L) by joining the overlapping or adjacent side edges (16, 17) of the paperboard laminate sheet (2") to form a tubular body (2), the tubular body (2) having an inner surface (7) facing the interior of the tubular body (2) and an outer surface (8) facing away from the interior of the tubular body (2); b) To give the tubular body (2) a predetermined cross-sectional shape; c) The tubular body (2) is closed at the bottom (3) and at the bottom opening (4) of the container, which is opposite to the top opening (5) of the container at the top (6) of the tubular body (2). d) Pulp fibers are provided into a molding tool (15), the molding tool (15) including a female molding tool part (15a) and a male molding tool part (15b), and the pulp fibers are pressed and molded between the female molding tool part and the male molding tool part to form a three-dimensional edge part (9) comprising 100% pulp fibers, the edge part (9) including a first connecting portion (11) having a first distal edge (11a). e) A first adhesive layer (14) comprising a thermoplastic adhesive is provided to the first connecting portion (11) of the edge member (9), or alternatively or additionally, along the end edge (12) of the tubular body (2) to the end portion (10) of the tubular body (2), the amount of the thermoplastic adhesive being per millimeter around the top opening at the end portion (10). t ) and the area around the bottom opening (p b Starting from 0.1 mg; as well as f) The edge member (9) is provided to the end portion (10) thereby adhesively attaching the edge member (9) to the tubular body (2). Wherein, the edge member (9) formed in step d) includes a U-shaped track portion (13) with square sides, the track portion (13) including a first sidewall section (13a) and a second sidewall section (13b) and a bottom section (13c) facing the end edge (12) of the tubular body (2), and wherein, step e) includes arranging the edge member (9) such that the bottom section (13c) faces the end edge (12) of the tubular body (2).

19. The method according to claim 18, wherein, The density of the edge member (9) is 0.2 kg / dm³. 3 Up to 1.5 kg / dm 3 Within the range.

20. The method according to claim 18 or 19, wherein, The draft angle (α) between the bottom section (13c) and the first sidewall section (13a) is in the range of 0 to 5 degrees.

21. The method according to claim 18 or 19, wherein, In the edge member (9) formed in step d), the first connecting portion (11) includes a first sidewall section (13a) and a guide sidewall section (13d), the guide sidewall section (13d) extending from the first sidewall section (13a) and having a greater distance to the tubular body (2) than the first sidewall section (13a).

22. The method according to claim 18 or 19, wherein, The first connecting portion (11) is provided with a distance element (20), which faces the tubular body (2).

23. The method according to claim 18, wherein, The pulp fibers are cork fibers.

24. The method according to claim 19, wherein, The density of the edge member (9) is 0.2 kg / dm³. 3 Up to 1 kg / dm 3 Within the range.

25. The method according to claim 24, wherein, The density of the edge member (9) is 0.4 kg / dm³. 3 Up to 0.8 kg / dm 3 Within the range.

26. The method according to claim 22, wherein, The distance element (20) is a rib extending in the longitudinal direction (L).

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