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

Abstract

This disclosure relates to a composite paperboard container for bulk solids. The composite paperboard container (1) includes a tubular body (2) closed at its bottom end (3) and at a bottom opening (4) opposite to a top opening (5) at the top end (6) of the tubular body (2). The tubular body (2) has an inner surface (7) facing the interior of the container body (2) and an outer surface (8) facing away from the interior of the container body (2). The tubular body (2) extends in a longitudinal direction (L). The composite container (1) includes a rim (9) surrounding the top opening (5) and / or the bottom opening (4). The rim (9) is attached to the end portion (10) of the tubular body (2) at a connecting portion (11) along the end edge (12) of the tubular body (2). The connecting portion (11) of the rim (9) has a distal edge (11a). The tubular body (2) is made of a laminated sheet (8) comprising a carton base layer and a thermoplastic weldable layer (14). The edge member (9) is a molded edge member (9) comprising pulp fibers (such as cork pulp fibers). The tubular body (2) is welded to a connecting portion (11) of the edge member (9), and when viewed in the longitudinal direction (L) of the tubular body (2), the distal edge (11a) of the edge member is located at a distance from the end edge (12) of the tubular body, said distance being at least 4 mm, optionally in the range of 4 mm to 50 mm. 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 using the composite paperboard container of the following embodiments and the method for manufacturing the composite paperboard container described in 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 cardboard container for bulk solids includes a tubular body closed at its bottom end above a container bottom opening opposite to a container top opening at the top 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 in a longitudinal direction. The composite cardboard container includes an edge member surrounding the container top opening and / or the container bottom opening. The edge member is attached to an end portion of the tubular body at a connecting portion of the edge member along an end edge of the tubular body. The connecting portion of the edge member has a distal edge. The tubular body is made of a laminated sheet comprising a carton base layer and a thermoplastic weldable layer. The edge member is a molded edge member comprising pulp fibers. The tubular body is connected to the connecting portion of the edge member by welding. When viewed in the longitudinal direction of the tubular body, the distal edge of the edge member is located at a distance from the end edge of the tubular body, the distance being at least 4... mm, the edge member includes a U-shaped track portion with square edges, 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 the draft angle between the bottom section and the first sidewall section is in the range of 0 degrees to 10 degrees.

[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 comprising a paperboard base layer and a thermoplastic welded layer into a tube having a longitudinal direction and a radial direction perpendicular to the longitudinal direction, closing the tube in the longitudinal direction by joining 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 tube a predetermined cross-sectional shape; c) closing the tube at the bottom end above a container bottom opening opposite to the container top opening at the top end of the tubular body. The tubular body; d) providing pulp fibers into a molding tool to form an edge member comprising a three-dimensional shape of pulp fibers, the edge member including a connecting portion having a distal edge; e) providing the edge member along the end edge of the tubular body to the end portion of the tubular body such that the edge member surrounds the top opening and / or the bottom opening of the container such that, when viewed in the longitudinal direction of the tubular body, the distal edge of the connecting portion of the edge member is located at a distance from the end edge of the tubular body, the distance being at least 4 mm; and f) attaching the connecting portion of the three-dimensionally formed edge member to the end portion of the tubular body by welding to form the composite paperboard container.

[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 of the tubular body. The tubular body has an inner surface facing the interior of the container body and an outer surface facing away from the interior of the container body. The tubular body extends in a longitudinal direction. The composite container includes an edge member surrounding the container top opening and / or the container bottom opening. The edge member is attached to the end portion of the tubular body along its end edge at a connecting portion. The connecting portion of the edge member has a distal edge. The tubular body is made of a laminated sheet comprising a carton base layer and a thermoplastic weldable layer. The edge member is a molded edge member comprising pulp fibers (such as cork pulp fibers). The tubular body is connected to the edge member by welding the end portion of the tubular body to the connecting portion of the edge member. When viewed in the longitudinal direction of the tubular body, the distal edge of the connecting portion is located at a distance of at least 4 mm from the end edge of the tubular body.

[0009] The edge is a molded edge comprising pulp fibers, which may be composed of 95% to 100% pulp fibers such as cork pulp fibers (optionally virgin cork pulp fibers), or 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.

[0010] The tubular body of the composite cardboard container is made of laminated sheet comprising a carton base layer and an inner thermoplastic welded layer. The composite cardboard packaging containers disclosed herein are intended for storing moisture-sensitive bulk solids and are not conventionally intended for storage in cooling spaces such as refrigerators, thus eliminating the need for an external polymer resin layer (such as polyethylene). However, the tubular body of this type of composite cardboard container is often provided with an external coating such as varnish to increase abrasion resistance and provide an aesthetically pleasing packaging container.

[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, which reduces the tightness of the seal between the edge piece and the tubular cardboard body. Therefore, the durability or security of the packaged goods is reduced due to the risk of air and / or moisture permeating the space between the tubular body and the edge piece. However, the inventors have unexpectedly discovered that by providing a connecting portion to the edge piece extending at least 4 mm longitudinally from the end edge of the tubular body and welding the edge piece to the tubular body having an inner layer with a thermoplastic weld layer, a satisfactory tightness of seal can be achieved, allowing for the packaging of sensitive goods such as food while also providing a neat appearance at the bottom or top container edges on easily recyclable containers. It has been found that the edge member has a connecting portion extending at least 4 mm in the longitudinal direction from the end edge of the tubular body, optionally extending 4 mm to 50 mm in the longitudinal direction from the end edge of the tubular body, optionally extending 5 mm to 40 mm in the longitudinal direction from the end edge of the tubular body. This provides enhanced shape stability to the edge member by providing support for the most vulnerable part of the edge member—that is, the connecting portion or multiple connecting portions—by means of the wall of the tubular body.

[0012] An edge member is attached to the end portion of a tubular body, and the end portion of the tubular body may surround a top opening or a bottom opening of the container. Composite cardboard containers may include the edge member according to this disclosure around both the top and bottom openings of the container.

[0013] The edge member can be an inner edge member, and the composite paperboard container can also include a lid member, which can be a molded lid member comprising pulp fibers such as cork pulp fibers, and can be made of the same material and in the same manner as the inner edge member. The lid member can include a lid portion and an outer edge portion, which can be molded integrally and connected to each other by a hinge portion. The outer edge portion can be connected to the inner edge member. The outer edge member can be mechanically connected to the inner edge member, such as by a snap-fit ​​connection, a slide-in connection, etc.

[0014] Alternatively, the edge member can be part of the edge and cover member, wherein the edge member and the edge portion of the cover member and the cover portion can be molded integrally, the edge portion is connected to the cover portion via a hinge portion, and wherein the edge portion is welded to the tubular body.

[0015] The edge member can be connected to the inner or outer surface of the tubular body via a first connecting portion. The first connecting portion is a circumferential connecting portion extending around the entire periphery of the tubular body. The first connecting portion is connected to the tubular body, to the outer surface and / or inner surface of the tubular body, along the entire end portion.

[0016] The edge fitting may have a thermoplastic layer on the surface facing the tubular body. The thermoplastic layer provides a more regular surface to the edge fitting, thereby enhancing the seal and improving the durability or packaging security of the packaged goods.

[0017] Cardboard packaging containers may be provided with an internal transport closure attached to the inner surface of a tubular body at its apex and spaced a distance from the edge. This transport closure may be completely or partially removable. The completely or partially removable transport closure may be airtight or breathable. An airtight closure may be made of any material or combination of materials suitable for providing an airtight seal to the compartment defined by the transport closure, such as aluminum foil, silicone-coated paper, plastic film, or laminates thereof. An airtight transport closure is advantageous when the bulk solids stored in the packaging container are sensitive to air and / or moisture and it is desirable to prevent the packaged bulk solids from contacting ambient air. Because the transport closure is removable, it does not affect the recyclability of the composite cardboard container.

[0018] Composite cardboard containers may be free of plastic parts—such as plastic rims, lids, or bottoms. Therefore, these composite cardboard containers allow users to recycle the containers without first separating the plastic parts from the tubular body.

[0019] 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 member according to this disclosure is a molded edge member, and therefore needs to have structural durability, preferably similar to the structural durability of plastic edge members. For edge members to be connected to additional edge portions—such as inner edge members and outer edge members—these edge members need to have a certain degree of flexibility and be structurally stable.

[0020] The edge component may include a U-shaped or square-U-shaped track portion, as seen in the cross-sectional view, comprising a first sidewall section and a second sidewall section as opposing sidewall sections, and a bottom section facing the end edge of the tubular body. 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. Since the walls of the tubular body are formed from cardboard blanks and thus have a thin rectangular cross-section, a draft angle in the range of 0 to 10 degrees or 0 to 5 degrees facilitates a tight fit between the tubular body, the bottom section, and the first sidewall section. This contributes to the durability and security of the packaged goods.

[0021] 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 means that the first and second sidewall sections have a constant distance. Therefore, the first and second sidewall sections can be well aligned with the inner and outer surfaces of the tubular body, thereby leaving only a small gap between the first and second sidewall sections of the tubular and edge members.

[0022] The edge member may include an L-shaped connecting portion, as seen in the cross-sectional view, comprising a first sidewall section and a bottom section facing the end edge of the tubular body. The edge member may have an L-shaped cross-section. The draft angle between the bottom section and the first sidewall section is in the range of 0 to 10 degrees, or in the range of 0 to 5 degrees. The first sidewall section may be applied against the inner surface of the tubular body, and wherein the first sidewall section corresponds to the connecting portion of the edge member. 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.

[0023] The edge member may include a guide sidewall section extending from the first connecting portion (such as from the first sidewall section). The guide sidewall section is a section that is further from the tubular body than the first connecting portion. The guide sidewall section may 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 the longitudinal direction of the tubular body. Because the edge member is made of pulp fibers, this structure is more fragile and less flexible than a plastic edge member, and can additionally generate greater friction between the edge member and the tubular cardboard body. To reduce the risk of damage to the edge member or edge portion when attaching the edge member to the tubular body, the edge member may include a guide sidewall section extending from the first sidewall section. It is advantageous when the edge member includes a U-shaped or square-sided U-shaped track portion into which the end portion of the tubular body is inserted.

[0024] The tubular body can have a basis weight of at least 15 g / m² on the laminated sheet. 2Such as at 20 g / m 2 Up to 160 g / m 2 Within the range, optionally 35 g / m 2 Up to 140 g / m 2 or 40 g / m 2 Up to 120 g / m 2 The thermoplastic weldable layer. The inventors have discovered that this basis weight of the thermoplastic weldable layer provides enhanced welding to the edge member comprising pulp fibers. Conventionally, the edge member is a plastic edge member, thus facilitating welding between the plastic edge member and the cardboard container comprising the thermoplastic weldable layer. However, if the thermoplastic weldable layer has such a basis weight, a durable and moisture-proof improved seal can be achieved between the edge member and the tubular body according to the invention.

[0025] The thermoplastic weld layer may include or be composed of a polyethylene layer.

[0026] Thermoplastic weld layers may include metal powder dispersed therein or metallized polymers.

[0027] The laminated sheet may include a metal foil layer such as aluminum foil. The metal foil layer may be disposed between the carton base layer and the thermoplastic welded layer. An adhesive layer (such as a thermoplastic adhesive layer) may be disposed between the metal foil layer and the carton base layer. The thickness of the metal foil layer may be from 5 micrometers to 30 micrometers, such as from 5 micrometers to 15 micrometers, such as from 5.5 micrometers to 6.5 micrometers.

[0028] In addition to the mandatory structural carton base layer and internal thermoplastic welded layer (f) disclosed below, the laminated body sheet that can be used in the composite packaging containers disclosed herein may also include one or more layers. As seen in the order from the outside to the inside, the laminated body sheet may have the following structure:

[0029] a) Optional polymer coatings, such as laquer.

[0030] b) Optional printing and / or coloring layers,

[0031] c) Cardboard box base layer,

[0032] d) Optional polymer adhesive layer, such as a polyethylene (PE) layer,

[0033] e) Optional barrier layer, such as an aluminum (Al) foil barrier layer,

[0034] f) An internal thermoplastic weld layer, such as a polyethylene (PE) layer. The internal thermoplastic weld layer may consist of two or more sublayers, such as a polyethylene (PE) layer and a low-density polyethylene (LDPE) layer. The sublayers may be co-extruded to form the internal polymer layer, or they may be formed as separate films laminated together.

[0035] 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:

[0036] 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 in the longitudinal direction 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.

[0037] b) To give the tube a predetermined cross-sectional shape;

[0038] 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;

[0039] d) Pulp fibers, such as cork pulp fibers, are fed into a molding tool to form an edge member comprising a three-dimensional shape of pulp fibers, the edge member including a connecting portion having a distal edge;

[0040] e) Providing an edge member along the end edge of the tubular body to the end portion of the tubular body, such that the edge member surrounds the top opening and / or bottom opening of the container, and the distal edge of the connecting portion of the edge member is located at a distance of at least 4 mm from the end edge of the tubular body; and

[0041] f) The connecting parts of the three-dimensionally shaped container components are welded to the end parts of the tubular body to form a composite cardboard container.

[0042] The method may include: step d) comprising forming an edge member such that it includes a U-shaped or square-sided U-shaped track portion, the U-shaped or square-sided U-shaped track portion including a first sidewall section and a second sidewall section and a bottom section, and wherein step e) comprises arranging the edge member such that the bottom section faces the end edge of the tubular body.

[0043] The draft angle between the bottom section and the first sidewall section can be in the range of 0 to 10 degrees, and optionally in the range of 0 to 5 degrees.

[0044] The distance between the first sidewall section and the second sidewall section can vary by less than 3 mm along the first and second sidewall sections. This means that there is a constant distance between the first sidewall section and the second sidewall section, and thus it can be aligned with the inner and outer surfaces of the tubular body, leaving only a small gap between the tubular body and the first and second sidewall sections of the edge piece.

[0045] 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. For edge components that will 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. Attached Figure Description

[0046] Figure 1 A composite cardboard container according to this disclosure is shown;

[0047] Figure 2 The paperboard blank is shown;

[0048] Figure 3 This illustrates folding a cardboard blank into a tubular body;

[0049] Figure 4-5 The diagram shows a cardboard tray being inserted into a tubular body to form the bottom of the container.

[0050] Figure 6 This demonstrates the use of molded pulp fibers to form the edge and cover components;

[0051] Figure 7 A molded edge component including an inner edge component and an outer edge and cover component is shown;

[0052] Figure 8 This illustrates attaching the inner edge component to the tubular body by welding; and

[0053] Figure 9 The diagram illustrates attaching the outer edge and the cover component to the inner edge component, thereby forming a composite cardboard container prepared by the method according to this disclosure. Detailed Implementation

[0054] 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.

[0055] 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.

[0056] 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 container body 2 and an outer surface 8 facing away from the interior of the container body 2. The tubular body 2 extends in a longitudinal direction L between the bottom end 3 and the top end 6. The composite container 1 includes an edge 9 surrounding the top opening 5 of the container. The edge 9 is a molded inner edge 9a, which includes pulp fibers, such as cork pulp fibers. The inner edge 9a is attached to the tubular body 2 by welding a connecting portion 11 of the inner edge 9a along the end edge 12 of the tubular body 2 to the end portion 10 of the tubular body 2. The connecting portion 11 of the inner edge member 9a has a distal edge 11a, which is provided at a distance d from the end edge 12 of the tubular body, the distance d being in the range of 4 mm to 50 mm.

[0057] The composite container 1 also includes a lid component comprising an outer edge 9b and a lid portion 9c. The outer edge 9b and lid portion 9c are molded integrally. The outer edge 9b is connected to the lid portion 9c via a hinge portion 9d. The outer edge 9b is connected to an inner edge 9a, and the outer edge 9b can be connected by a snap-fit ​​function, a slide-in connection, an adhesive, or any other suitable means. The lid component is made of the same material as the inner edge 9a.

[0058] As seen in the cross-sectional view, the inner edge member 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 first sidewall section 13a corresponds to the connecting portion 11 of the inner edge member 9a. However, the inner edge member may also have an L-shaped cross-section, wherein the first sidewall section corresponds to the connecting portion of the edge member and the bottom section is arranged to face the end edge 12 of the tubular body 2.

[0059] The tubular body 2 is made of laminated sheet material including a cardboard base layer and a thermoplastic welded layer 14.

[0060] Figures 2 to 9 A method for producing composite paperboard containers 1 for bulk solids is shown. Figure 2 A cardboard laminate sheet 2 is shown, comprising a carton base layer and a thermoplastic welded layer 14. 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 16, 17 may be covered by a sealing strip. Alternatively, the side edges 16, 17 may be overlapped. 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 weld layer 14 of the laminate sheet is disposed on the inner surface 7 of the tubular body 2. The tube is formed to have a predetermined cross-sectional shape. 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.

[0061] Figure 4 and Figure 5 The step c) of closing the tubular body 2 at the bottom end 3 above the container bottom opening 4, which is opposite to the container top opening 5 at the top end 6 of the tubular body 2, is shown. The bottom opening 4 is closed by pressing a cardboard base 18 into the tube at the bottom end 3. The base 18 has an outer peripheral flange 18a that bends toward the bottom end 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 comprising a carton base layer and a thermoplastic weldable layer. A bottom edge can be applied to the bottom end 3 of the tubular body, which can be a molded edge comprising pulp fibers according to the present disclosure and can be applied by welding or attached by adhesive according to the present disclosure.

[0062] Figure 6 The steps for forming a cover member including an outer edge portion 9b and a cover portion 9c are shown. The molded outer edge portion and cover portion are formed by providing cork pulp fibers, such as pulp liquid, 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 a cover member with a three-dimensional shape including pulp fibers. Figure 7 The inner edge piece 9a shown is molded in a corresponding manner.

[0063] Figure 7 An inner edge member 9a and a cover member are shown. The cover member includes an outer edge portion 9b and a cover portion 9c, which are molded integrally. The outer edge portion 9b is connected to the cover portion 9c by two hinge portions 9d.

[0064] As seen in the cross-sectional view, the inner edge member 9a has a U-shaped track portion 13, which includes a first sidewall section 13a, a second sidewall section 13b, and a bottom section 13c that will face the end edge 12 of the tubular body 2. The first sidewall section 13a corresponds to the connecting portion 11 of the inner edge member 9a. However, the edge member can also be equivalently L-shaped, wherein the first sidewall section corresponds to the connecting portion of the edge member and the bottom section will face the end edge 12 of the tubular body 2. 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.

[0065] Figure 8 The figure illustrates the steps of attaching the inner edge member 9a around the top opening 5 of the container by welding the inner edge member 9a along the end edge 12 of the tubular body 2 to the end portion 10 of the tubular body 2. In this figure, the welding is performed by a welding unit 19 including an induction coil 19a and a compression plunger 19b.

[0066] Welding unit 19 includes a high-frequency induction welding unit with induction coil 19a. The compression plunger 19b includes an expandable welding tool 51 that can switch between an unexpanded state and a radially expanded state.

[0067] In the extended state, the cross-sectional area (occupied space) defined by the outer periphery of the welding tool 51 is larger than the cross-sectional area in the unextended state of the welding tool 51.

[0068] When the compression plunger 19b is inserted into the tubular body 2 with the welding tool 51 in the attached position of the inner edge member 9a, the welding tool 51 changes to the extended state.

[0069] In the extended state of the welding tool 51, the edge portion of the outer periphery of the welding tool 51 contacts the inner edge member 9a inserted into the tubular body 2, and pressure is applied to the inner edge member 9a so that it presses against the interior of the tubular body 2, thereby being inductively welded to the interior of the tubular body 2 by activating the induction coil 19a.

[0070] Figure 9 The steps are shown: when the inner edge 9a is attached to the end portion 10 of the tubular body 2, and when the outer edge 9b and the cover portion 9c are attached to the inner edge 9a by means of a snap-fit ​​engagement.

Claims

1. A composite paperboard container (1) for bulk solids, the composite paperboard container (1) comprising a tubular body (2) closed at its bottom end (3) and above a container bottom opening (4) opposite to a container top opening (5) at the 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 in a longitudinal direction (L), the composite paperboard The container (1) includes an edge member (9) surrounding a top opening (5) and / or a bottom opening (4) of the container, the edge member (9) being attached at a connecting portion (11) of the edge member (9) along the end edge (12) of the tubular body (2) to the end portion (10) of the tubular body (2), the connecting portion (11) of the edge member (9) having a distal edge (11a), the tubular body (2) being made of a laminated sheet comprising a carton base layer and a thermoplastic welded layer (14), characterized in that, The edge member (9) is a molded edge member (9) comprising pulp fibers. The tubular body (2) is connected to the connecting portion (11) of the edge member (9) by welding. When viewed in the longitudinal direction (L) of the tubular body (2), the distal edge (11a) of the edge member is located at a distance of at least 4 mm from the end edge (12) of the tubular body. The edge member (9) includes a U-shaped track portion (13) with square edges, the track portion 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), wherein 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 edge member (9) is an inner edge member (9a), and the composite paperboard container (1) includes a lid member, which is a molded lid member comprising pulp fibers, the lid member including an outer edge portion (9b) and a lid portion (9c), wherein the outer edge portion (9b) and the lid portion (9c) are molded integrally, the outer edge portion (9b) is connected to the lid portion (9c) via a hinge portion (9d), and wherein the outer edge portion (9b) is connectable to the inner edge member (9a).

3. The composite paperboard container (1) according to claim 1 or 2, wherein, The composite cardboard container (1) does not contain plastic edge parts, lid parts or bottom parts.

4. The composite paperboard container (1) according to claim 1 or 2, wherein, The density of the edge component (9) is 0.2 kg / dm³. 3 Up to 1.5 kg / dm 3 Within the range.

5. The composite paperboard container (1) according to claim 1, wherein, The edge member (9) includes a guide sidewall section (13d) extending from the first sidewall section (13a), the guide sidewall section being an inclined wall section, the distance of the inclined wall section to the tubular body (2) increasing when viewed from the end edge (12) of the tubular body (2) in the longitudinal direction (L) of the tubular body (2).

6. The composite paperboard container (1) according to claim 1 or 2, wherein, The thermoplastic weld layer (14) includes or is composed of a polyethylene layer.

7. The composite paperboard container (1) according to claim 1 or 2, wherein, The thermoplastic weld layer (14) on the laminated sheet has a basis weight of at least 15 g / m². 2 .

8. The composite paperboard container (1) according to claim 1 or 2, wherein, The laminated sheet includes a metal foil layer.

9. The composite paperboard container (1) according to claim 1, wherein, The distance is in the range of 4 mm to 50 mm.

10. 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.

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

12. The composite paperboard container (1) according to claim 2, wherein, The cover component is a molded cover component comprising cork pulp fibers.

13. The composite paperboard container (1) according to claim 3, wherein, The composite cardboard container (1) does not contain any plastic parts.

14. The composite paperboard container (1) according to claim 4, wherein, The density of the edge component (9) is 0.2 kg / dm³. 3 Up to 1kg / dm 3 Within the range.

15. The composite paperboard container (1) according to claim 14, wherein, The density of the edge component (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 7, wherein, The basis weight of the thermoplastic weld layer (14) on the laminated sheet is 20 g / m². 2 Up to 160 g / m 2 Within the range.

17. The composite paperboard container (1) according to claim 16, wherein, The basis weight of the thermoplastic weld layer (14) on the laminated sheet is 35 g / m². 2 Up to 140 g / m 2 Within the range.

18. The composite paperboard container (1) according to claim 17, wherein, The basis weight of the thermoplastic weld layer (14) on the laminated sheet is 40 g / m². 2 Up to 120 g / m 2 Within the range.

19. A method for producing a composite paperboard container (1) for bulk solids according to any one of the preceding claims, the method comprising the following steps; a) A paperboard laminate (2") comprising a paperboard base layer and a thermoplastic weld layer (14) is bent into a tube (2') having a longitudinal direction (L) and a radial direction (R) perpendicular to the longitudinal direction (L). The tube (2') is closed in the longitudinal direction (L) by joining the overlapping or adjacent side edges (16, 17) of the paperboard laminate (2") to form a tubular body (2), such that 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). b) To give the tubular body (2) a predetermined cross-sectional shape; c) The tubular body (2) is closed at the bottom end (3) above the container bottom opening (4) opposite to the container top opening (5) at the top end (6) of the tubular body (2). d) Pulp fibers are fed into a molding tool (15) to form an edge member (9) comprising a three-dimensional shape of pulp fibers, the edge member (9) comprising a connecting portion (11) having a distal edge (11a). e) The edge member (9) is provided along the end edge (12) of the tubular body (2) to the end portion (10) of the tubular body (2), such that the edge member (9) surrounds the top opening (5) and / or the bottom opening (4) of the container, such that when viewed in the longitudinal direction (L) of the tubular body (2), the distal edge (11a) of the connecting portion (11) of the edge member is located at a distance from the end edge (12) of the tubular body, said distance being at least 4 mm; and f) The connecting portion (11) of the three-dimensionally shaped edge piece (9) is attached to the end portion (10) of the tubular body (2) by welding, thereby forming the composite cardboard container (1).

20. The method according to claim 19, wherein, Step d) includes forming the edge member (9) comprising a U-shaped track portion (13) including a first sidewall section (13a), a second sidewall section (13b), and a bottom section (13c), 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).

21. The method according to claim 20, wherein, 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.

22. The method according to any one of claims 19-21, wherein, The density of the edge member (9) is 0.2 kg / dm³. 3 Up to 1.5 kg / dm 3 Within the range.

23. The method according to claim 19, wherein, The distance is in the range of 4 mm to 50 mm.

24. The method according to claim 19, wherein, The pulp fiber is cork pulp fiber.

25. The method according to claim 21, 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.

26. The method according to claim 22, wherein, The density of the edge member (9) is 0.2 kg / dm³. 3 Up to 1 kg / dm 3 Within the range.

27. The method according to claim 26, wherein, The density of the edge member (9) is 0.4 kg / dm³. 3 Up to 0.8 kg / dm 3 Within the range.

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