Method and device for producing a biodegradable hollow body with a connecting element

Abstract

The invention relates to a method and a device for producing a container with a hollow body (1) made of fibrous material having an opening (2) and a connecting element (3) arranged on the hollow body and surrounding the opening (2). The object of the invention is to provide a method with a short process time and a low energy input. The method comprises the following method steps: - providing a partitioned suction mould (4) having a porous wall (5) that, in the closed state, surrounds at least one cavity (6) with a mould opening (7); - arranging the connecting element (3) on a holder (8) and inserting the holder (8) into the cavity (6) of the suction mould (4) in such a way that the holder (8) protrudes through the mould opening (7) and holds the connecting element (3) in the mould opening (7); - closing the partitioned suction mould (4) and sucking fibrous material from a pulp (13) through the wall (5) of the suction mould (4) in such a way that a hollow body (1) is formed between the holder (8) and the wall (5); - compacting the hollow body (1) with the connecting element (3) arranged thereon; and - drying the hollow body (1). To enable reliable handling of the hollow body, the hollow body (1) is removed from the partitioned suction mould (4) by the holder (8).

Description

METHOD AND DEVICE FOR PRODUCING A BIODEGRADABLE HOLLOW BODY WITH A CONNECTING ELEMENT Technical area

[0001] The invention relates to a method for producing a container comprising a hollow body made of fiber material with an opening and a connecting element arranged on the hollow body and surrounding the opening, in accordance with the preamble of claim 1, in particular a method based on the fiber molding process. The invention also relates to an apparatus for producing a container according to the said method.

[0002] Molded pulp is used for a variety of purposes, particularly as transport packaging and as molded inserts in packaging to protect sensitive goods. With the goal of further reducing the amount of plastic waste generated by packaging materials, the use of molded pulp to contain cosmetic and food products has also received increasing attention. In particular, hollow fiber bodies with a sealable opening are being sought for use as jars for cosmetic products, such as creams, or as containers for food products, such as liquids. Achieving suitable mechanical properties and manufacturing such hollow fiber bodies pose challenges.

[0003] Achieving suitable mechanical properties is particularly important in the area of ​​the opening of the hollow body. Since the opening must be able to be sealed tightly for use in cosmetic and food products, sealing films and / or closure caps made of polymers are regularly arranged as closures at the openings. A firm connection of the closures to the hollow body is necessary to prevent the closures from uncontrolled release. A firm connection of a sealing film can be achieved by gluing or welding the sealing film. A smooth surface to which the sealing film is attached is advantageous for this. A firm connection of closure caps can be achieved by firmly pushing or screwing on the cap. This requires high strength of the closure caps and the area where a closure cap is arranged, which is why the fiber material is regularly reinforced.

[0004] In order to meet the above requirements, it is known in practice to provide containers as a combination of a molded fiber body having an opening and a connecting element reinforcing the area of ​​the opening. The connecting element of such a container can in practice be formed from a polymer using an injection molding process and have greater strength, greater hardness and / or a smoother surface suitable for the adhesion of sealing films than the fiber material of the hollow body. Thus, a closure can easily be attached to the connecting element, which securely closes the opening of the hollow body (or the container). The connecting element can also have special design details such as an external thread with which an internal thread of a closure designed as a screw cap interacts.The applicant has developed a thermoplastic material consisting exclusively of biodegradable or bioinert components. If the connecting element and closure of a container are made of biodegradable biopolymers, the entire container can be biodegradable.

[0005] The production of these containers has so far been complex. In prior art manufacturing processes, the molded fiber body is first produced using a fiber casting process. The connecting element is manufactured separately and bonded to the dried fiber body either by a form-fitting or material-fitting process. Alternatively, the connecting element can be injection-molded onto the dried fiber body.

[0006] For example, EP 1 221 413 A1 discloses a container with a fiber molded article having a resin layer on its inner surface and / or outer surface, which resin layer is formed by applying a coating, wherein a specific thickness ratio of the resin layer to the molded article is created and the inner and outer surfaces have an average centerline roughness (Ra) of 0.5 to 20 μm. The fiber molded article is formed in a multi-step process. First, pulp is poured into a cavity of a split mold. The water from the pulp is sucked out through mesh-covered holes in the wall of the split mold, thereby forming the fiber molded article on the wall. Subsequently, an elastic and expandable pressing tool is inserted into the cavity of the fiber molded article and expanded to dewater and densify the fiber molded article.After the fiber molded body has been compacted, the compression mold retracts and is removed. The split mold is opened to remove the wet fiber body. The fiber molded body is then pre-dried, coated, and finally dried. Optionally, the container includes a connecting element containing 40 to 90 wt.% natural fibers and a binder. The attachment of the connecting element to the fiber body is not described in detail.

[0007] Similar methods for producing a hollow body made of fiber material in the shape of a bottle using a split mold and an expandable pressing tool are also described in EP 1 081 285 B1 and WO 2003 / 010386 A1. These documents also do not disclose the attachment of a connecting element to the fiber body.

[0008] A method according to the preamble of claim 1 is known from document JP 2001-303 500 A. Summary of the invention

[0009] The invention is based on the object of providing a method and a device that enable the efficient production of a container as described above. In particular, the method should enable a short process time and low energy input, as well as create a reliable connection between the connecting element and the hollow body and enable reliable handling of the hollow body.

[0010] According to the invention, this object is achieved by a method having the features of claim 1 and by a device having the features of claim 12. Advantageous embodiments emerge from the dependent claims.

[0011] The method described here for producing a container comprises the following method steps: Providing a split suction mold with a porous wall which, when closed, encloses at least one cavity with a suction mold opening; Arranging the connecting element on a holder and inserting the holder into the cavity of the suction mold such that the holder extends through the suction mold opening and holds the connecting element in the suction mold opening; Closing the split suction mold and sucking fiber material from a pulp through the wall of the suction mold, so that a hollow body made of fiber is formed between the holder and the wall; Compacting the formed hollow body with the connecting element arranged thereon; and Drying the hollow body.

[0012] The split suction mold is composed of several suction mold parts, in particular of two halves. The hollow fiber molded body is formed when the suction mold is closed, when the suction mold parts are joined together and the wall of the suction mold encloses a largely closed cavity. The wall of the suction mold has a porous, water-permeable inner surface through which pulp can be sucked in. This inner surface can be realized in the conventional way using a suction mold, which has a largely solid base body made of plastic or metal, into which a sieve body is inserted to form the porous inner wall. However, it is also possible to produce the parts of the suction mold, for example using additive manufacturing techniques in 3D printing, whereby fluid channels are formed in the material of the molded parts during printing. The pores of the molded parts are connected to a suction device, which sucks water through the wall of the suction mold.The wall of the divided suction mold further contains at least one suction mold opening, which connects the cavity to an environment outside the suction mold. The suction mold opening can be formed in a contact area of ​​at least two suction mold parts and thus have a divisible periphery. Features of the method relating to the formation of the suction mold opening are described further below.

[0013] For the method according to the invention, a holder is provided on which a connection element is arranged. The holder is an elongated body which has at least one section with a cross-section which depends on the shape of the opening of the container to be produced. For example, the cross-section can be round if the opening of the container is to be round. If the opening is square, the said cross-section of the holder has a square shape. Likewise, in the case of an oval or other non-circular opening, the cross-section of the holder corresponds to the cross-section of the opening. The cross-section of the holder only has to correspond to the shape of the opening of the container to be produced in an area which is assigned to the opening of the container to be produced. The areas of the holder which are remote from the opening of the container to be produced can have any desired different cross-section.The connecting element can be arranged on the holder by means of a feed device, wherein the feed device places the connecting element in a predetermined position on the holder. The feed device can, for example, arrange the connecting element on the holder in such a way that it partially or completely encompasses the section of the holder in the region of the opening of the container to be produced.

[0014] The holder and the connecting element arranged thereon are introduced into the suction mold together. The connecting element is arranged in the suction mold opening and the holder projects through the suction mold opening such that it is arranged partly in the cavity and partly outside the suction mold. If the suction mold opening is formed in a contact area of ​​at least two suction mold parts and has a divisible circumference, the holder with the connecting element can be inserted into the open suction mold and the mold parts then closed. If the suction mold opening is not formed in a contact area of ​​at least two suction mold parts, the holder with the connecting element can be inserted into the suction mold in the longitudinal direction of the holder through the suction mold opening until the connecting element lies in the suction mold opening. The suction mold opening can be slightly larger than the connecting element, at least in one section.In this case, the connecting element can be held by the holder in the suction mold opening in such a way that a gap is formed between the connecting element and the suction mold opening.

[0015] After the holder and the connecting element have been positioned in the suction mold opening, the split suction mold is closed, and pulp is sucked into the cavity by immersing the suction mold and / or the holder into a pulp-filled basin. The holder can be hollow, allowing the pulp to be sucked into the suction mold through the hollow holder. The pulp contains water and fiber material. The fiber material usually consists of cellulose, such as waste paper or other recycled fibers, but can also contain virgin fibers, depending on the requirements for the optical properties of the fiber molded body. The pulp can contain other additives that positively influence the properties of the fiber molded body.

[0016] The pores in the porous wall of the suction mold are designed in such a way that the water penetrates the pores and the fiber material is deposited on the wall when the pulp is sucked in. As the suction time increases, the wall thickness of the hollow body formed increases. In particular, a fiber layer forms between the wall of the suction mold and the holder, in which fiber layer the connecting element is embedded. The fiber layer of the hollow body and the connecting element are positively connected. The connecting element can have a connecting wall with openings that extend approximately parallel to the porous wall. The connecting wall, for example made of injection-molded thermoplastic, can have a wall thickness of the order of 1 mm and openings with a clear area of ​​20 mm², for example. If the connecting element surrounds an opening in the container, the connecting wall can extend along the opening in a ring shape and have a width (wall thickness) of approx.5 to 15 mm. The fibers deposited on the wall form a layer that penetrates the openings in the connecting wall and thus embeds the connecting wall. The connecting element is thus firmly anchored in the fiber layer.

[0017] As soon as a sufficient amount of fiber material has been deposited in the cavity of the suction mold and / or a predetermined time has elapsed for the suction of fiber material, the formed hollow body is compacted with the connecting element arranged on it. Compaction means that water contained in the fiber molded body is mechanically removed from the fiber molded body. For this purpose, a relative overpressure can be generated in the internal volume of the hollow body, which presses water out of the wall of the hollow body. The relative overpressure in the suction mold can be generated by applying a negative pressure outside the suction mold parts, which is conducted through the porous wall of the mold parts to the inner wall of the mold parts and causes the fiber material to be deposited on the porous wall. Compacting the fiber molded body increases its mechanical stability and makes it easier to handle.However, an expandable pressing tool, described below, can also mechanically press the moisture out of the formed fiber layer while it is still in the suction form.

[0018] The hollow body with the connecting element can be dried by applying heat.

[0019] The container produced in this way can be filled, for example, with a flowable product, in particular a cream or a beverage. The opening of the container can then be provided with a closure that is tightly connected to the connecting element.

[0020] The method described above offers a number of advantages. The connecting element can be positioned very precisely and quickly in the suction mold opening using the holder. Furthermore, by forming the fiber layer of the hollow body around the connecting element, a particularly strong connection between the connecting element and the hollow body can be achieved. This is because the pulp has a low viscosity and can therefore penetrate even the most delicate geometric configurations (e.g., undercuts or openings in a connecting wall) of the connecting element, where it can dry and harden.

[0021] In practice, the holder can be hollow, allowing the pulp to flow through the holder into the cavity of the suction mold. This allows the entire internal cross-section of the hollow holder to be used for the pulp to flow into the suction mold, enabling rapid and complete filling of the suction mold.

[0022] The hollow body is removed from the split suction mold using the holder. The holder simplifies the handling of the hollow body and the transport to further processing steps. The hollow body can then be transported on the holder into a transfer mold complementary to the hollow body or a split compression mold. In other words, the hollow body can be transported on the holder from the suction mold directly into the compression mold complementary to it. Alternatively, the hollow body can be transported from the suction mold into the complementary transfer mold and from there into the likewise complementary compression mold. Details of the transfer mold and the compression mold are described below. The removal of the hollow body from the suction mold and the transport of the hollow body on the holder enable precise and fast positioning of the hollow body in the transfer mold or the compression mold. The holder also enables safe, i.e.Damage-free removal and transport of the hollow body is possible because the holder can mechanically support the hollow body. When the holder with the hollow body is moved out of the split suction mold, a portion of the hollow body rests on the holder. Particularly safe removal and transport are possible when the holder supports the hollow body essentially along its entire length, for example, when the holder extends into the hollow body all the way to its base.

[0023] For the purpose of removing and transporting the hollow body, it is advantageous if the suction mold opening is formed in a contact area of ​​at least two suction mold parts, as described above. The divided suction mold can be opened before or after the hollow body has been compacted, and the hollow body is removed from the opened suction mold with the holder.

[0024] In practice, the removal and transport of the hollow body on the holder is particularly quick and easy if the holder is pivoted about an axis located outside the cavity for transport into the transfer mold or the split compression mold. For this purpose, the holder can protrude from the cavity, with one end of the section protruding from the cavity being pivotally mounted about a pivot axis formed transversely to the longitudinal direction of the holder. After the split suction mold has been opened, the holder with the hollow body can be pivoted, for example, by 180° from a suction mold part of the split suction mold into a transfer mold or the opened, split compression mold. After the holder has been pivoted and the hollow body is arranged in the transfer mold or the compression mold, the transfer mold or the compression mold is moved in the longitudinal direction of the holder and the hollow body is pulled off the holder.

[0025] In practice, the hollow body can be compacted in the suction mold and / or the compression mold. Compacting in the suction mold facilitates removal of the hollow body, which is very wet without compaction, from the suction mold. However, it is possible that the pores and structures in the wall of the suction mold are reflected in the surface of the hollow body. In addition to compacting in the suction mold, or alternatively, the hollow body can therefore be compacted in a specially provided compression mold. For this purpose, the hollow body is transported from the suction mold to the compression mold.

[0026] The split mold is formed from a plurality of mold parts. In the closed state, the mold has a wall that is substantially complementary to the hollow body and the connecting element. Furthermore, the mold has a mold opening that is aligned with the opening of the hollow body arranged in the mold. The wall of the mold can have either no pores or very small pores compared to the pores in the wall of the suction mold. It can also have decorative structures (grooves or projections) that are embossed into the wall of the container during the pressing process. The wall of the mold can also comprise a suction channel that is fluidly connected to the interior of the mold and through which water can be drained away. The hollow body can be placed in the opened mold and removed from it after pressing.When the hollow body is placed in the closed mold, the mold wall encloses the hollow body, and the internal pressure in the hollow body's interior volume is increased by a pressing tool, thereby compacting the hollow body. Excess water flows out of the hollow body, preferably through the suction channel.

[0027] In practice, the hollow body can be compacted by expanding an expandable compression tool inserted into the hollow body while the hollow body is inside the compression mold. This allows the hollow body to be quickly and efficiently dewatered and acquire the desired surface structure both on the inside by the compression tool and on the outside by the inner surface of the compression mold wall.

[0028] In practice, the expandable compression tool can consist of a bladder or balloon made of an elastomer or other rubber-elastic material and be arranged on a second holder, which can be inserted, in particular, through the compression mold opening into the interior volume of the hollow body arranged in the compression mold. The second holder has a sealable fluid line tightly connected to the compression tool, through which a fluid can be forced under excess pressure into the interior of the compression tool. The fluid can be, for example, water, oil, air, industrial gases, or a mixture of the above fluids.

[0029] To compact the hollow body with the compression tool in the mold, the second holder is inserted into the interior volume of the hollow body, and the compression tool expands by injecting the fluid. The compression tool expands like a balloon, rests against the inner surface of the hollow body, and presses it against the wall of the mold. The isostatic fluid pressure leads to uniform compaction of the wall of the hollow body. After a predetermined compression time or a predetermined drainage of the hollow body, the fluid is released from the compression tool through the fluid line, causing it to contract again, and the compression tool is withdrawn from the container with the second holder.

[0030] It is also possible to compress the hollow body with the compression tool in the suction mold. For this purpose, the first holder can be pulled out through the suction mold opening while the suction mold is closed, and the second holder can be pushed into the hollow body through the suction mold opening. Compression then takes place in the same way as compression in a compression mold. Alternatively, the compression tool can also be mounted on the holder that supports the connecting element.

[0031] In practice, the hollow body can be dried from the inside using radiant heat and / or a hot air stream. For this purpose, a rod-shaped heating device can be inserted through the opening of the hollow body. The heating device can be activated inside the hollow body and emit infrared radiation, UV radiation, and / or microwave radiation. Additionally or alternatively, a hot air stream can emerge from the rod-shaped heating device, flowing along the inner surface of the hollow body and exiting the opening into the environment. Drying the hollow body removes residual moisture from the fiber material. This allows optional coatings to solidify on the inner surface of the hollow body. Details on the application of optional coatings are explained below.

[0032] In practice, the connecting element can be injection-molded from a thermoplastic and, once cured, pushed onto the holder. Injection-molded connecting elements made of thermoplastic can be designed with virtually no geometrical constraints, meaning they have only a few structural limitations. Such a connecting element can, for example, have a grid-shaped casing section with openings that forms a connecting wall and is arranged in the area of ​​the container opening. The connecting wall has openings through which the fiber material of the hollow body penetrates.

[0033] In another practical embodiment of the process, the hollow body can be pre-dried in an oven before compaction. The hollow body can be located in a part of the compression mold or transfer mold that is transported through the oven. Or the hollow body can be placed on a conveyor belt that transports it through the oven. Pre-drying allows the water content of the hollow body to be reduced even before compaction. The oven can, in particular, be a continuous oven. The reduced residual moisture in the hollow body results in greater dimensional stability of the hollow body in the subsequent compaction step.

[0034] In another practical embodiment, the hollow body can additionally be coated on its inner surface with a biodegradable coating solution. For coating the inner surface, a conduit fluidly connected to a supply of coating solution can be introduced through the opening of the container into the inner volume of the hollow body. The coating solution can then be introduced into the inner volume through the conduit. This allows a coating to be created that is suitable for contact with food or liquids. If the coating is applied after compaction and before final drying, the coating can be particularly durable.

[0035] Coating the inner surface is particularly easy in practice if the hollow body is rotated after the coating solution has been added, thereby wetting its inner surface. For this purpose, a reservoir of the coating solution can be formed in the hollow body, with excess coating solution being poured out after the inner surface has been wetted. The rotation can be carried out using a rotating device, by means of which the hollow body is rotated around the axis of the container's opening.

[0036] The invention also relates to an apparatus for producing a container according to one of the above-described embodiments of the method. The apparatus comprises: a basin for a pulp; a divided suction mold with at least one cavity and a porous wall surrounding the cavity; a first holder movable into the divided suction mold; a suction device; and a feeding device for an annular connecting element to the first holder.

[0037] This device is used in particular to implement the method described above.

[0038] In practice, the apparatus may further comprise at least one of the following features: a transfer mold; a furnace; a transfer device; a split mold; a second holder insertable into the split mold and having an expandable pressing tool; an injector for a coating solution; a rotation device; a radiant heat source.

[0039] Further practical embodiments and advantages of the invention are described below in conjunction with the drawings.

[0040] shows a three-dimensional partial view of a device according to the invention with a plurality of suction molds and holders.

[0041] shows a further three-dimensional partial view of the device with connecting elements located on the holders.

[0042] shows a further three-dimensional partial view of the device from and 2 with holders arranged in the suction molds.

[0043] shows another three-dimensional partial view of the device with the suction molds in a pulp tank.

[0044] shows another three-dimensional partial view of the device with hollow bodies and transfer molds on the suction molds.

[0045] shows another three-dimensional partial view of the device with the transfer molds and the hollow bodies in a continuous furnace.

[0046] shows another three-dimensional partial view of the device in which the hollow bodies are in press molds.

[0047] shows an isolated three-dimensional view of a hollow body in a mold with a pressing tool.

[0048] shows an isolated three-dimensional view of a hollow body in a mold with an expanded pressing tool.

[0049] shows another three-dimensional partial view of the device with injectors for coating the hollow bodies.

[0050] shows a further three-dimensional partial view of the device with a drying device for the hollow bodies. Description of the embodiments

[0051] Figures 1 to 9 illustrate the process of the method according to the invention and an apparatus for carrying out the method. The figures show an apparatus capable of producing ten containers simultaneously. It should be noted that the method and apparatus according to the invention are not limited to the simultaneous production of ten containers. Rather, the number of containers produced simultaneously can be adapted to requirements. The following describes the production process using the example of a single container, which takes place simultaneously in the molds. In Figures 1 to 11, identical components are provided with identical reference numerals.

[0052] To produce a container with a hollow body 1 made of fibrous material and an opening 2, and with a connecting element 3 arranged on the hollow body 1 and surrounding the opening 2, a split suction mold 4 with a porous wall 5 is first provided. The suction mold 4 is rotationally symmetrical and divided along its central longitudinal plane into two suction mold parts 4a, 4b. The suction mold parts 4a, 4b are pivotally connected to one another at a first end about a pivot axis and can be folded open along the pivot axis. In the closed state, the suction mold parts 4a, 4b enclose a cavity 6 with their inner wall 5, which is connected to the environment by means of a suction mold opening 7 in the suction mold 4. The wall 5 has pores (not shown) that fluidly connect the inner wall 5 of the cavity 6 to a suction device (not shown).In an inner region of the suction mold parts 4a, 4b (not shown), the pores are guided to first suction channels 9, through which the pores and the cavity 6 are fluidly connected to a suction device. In the illustrated embodiment, the suction channels 9 are formed by steel tubes that are attached to the suction mold part 4a and support the suction mold 4.

[0053] The suction mold opening 7 is located at an end of the suction mold 4 opposite the first end, in a contact area between the two suction mold parts 4a, 4b. Thus, when the suction mold 4 is opened, the suction mold opening 7 is also opened.

[0054] A first holder 8 is arranged in an area in front of the suction mold opening 7. The first holder 8 has two sections 8a, 8b. The first section 8a is hollow cylindrical and the second section 8b, which protrudes from the first section 8a, is designed as a bent perforated sheet and extends over part of the circumference of the first section 8a. The second section 8b is integrally or at least seamlessly connected to the first section 8a and both sections 8a, 8b have the same curvature. The first holder 8 is thus an elongated body which, by means of a shaft 10 oriented transversely to the longitudinal direction of the first holder 8, is pivotably arranged in a receptacle for the shaft 10 fastened to the suction mold 4. The first holder 8 can be pivoted from the position shown in Figures 1 and 2 outside the suction mold 4 into the position shown in Figure 1 in which it extends through the suction mold opening 7 into the interior of the suction mold 4.It then extends through almost the entire cavity 6 of the suction mold 4.

[0055] The first holder 8 is located in the vertical orientation in front of the suction mold opening 7 and below a feed device 11 for feeding an annular connecting element 3 to the first holder 8. The feed device 11 can, for example, have a tube that is open at at least one end and in which one or more connecting elements 3 are received. The connecting element 3 is made of an injection-molded and biodegradable thermoplastic in the shape of a cured ring. As can be seen in Figures 1 and 2, the tube with the tube opening can be moved over the free end of the second section 8b of the first holder 8, thereby pushing a connecting element 3 onto the first holder 8 up to the first section 8a. The cross-sectional shape of the tube, the first section 8b of the first holder 8, and the suction mold opening 7 are complementary to one another and can deviate from the circular shape shown in the drawings.They depend in particular on the shape of the opening of the container to be manufactured.

[0056] After the connecting element 3 is arranged on the first section 8a of the first holder 8, the tube of the feed device 11 is removed from the first holder 8 and the holder 8 is pivoted about the pivot axis of the shaft 10 into the cavity 6 and the suction mold opening 7, as shown in Figure 3. The suction mold 4 is then closed by folding the suction mold parts 4a, 4b together. The first holder 8 extends through the suction mold opening 7 and, with the first section 8a, holds the connecting element 3 in the suction mold opening 7 such that a gap is formed between the connecting element 3 and the suction mold opening 7.

[0057] The closed suction mold 4 with the first holder 8 located therein is immersed in a basin 14 filled with pulp 13. The suction mold 4 is attached to a hollow rotating shaft 15 via the suction channels 9. The interior of the hollow rotating shaft 15 is connected to the suction device, which generates a vacuum and sucks out water. This vacuum is guided through the tubular stainless steel suction channels 9 to the wall 5 of the suction mold 4. All suction molds 4 connected to the rotating shaft 15 via the suction channels 9 are moved through the pulp basin 14 when the rotating shaft 15 rotates.

[0058] The pulp 13 is sucked through the hollow cylindrical first section 8a of the holder 8 into the suction mold 4. As the water of the pulp 13 passes through the pores, the fiber material from the pulp 13 is deposited at the pores and forms a layer along the entire wall 5 of the cavity 6 of the suction mold 4. In this way, a hollow body 1 made of deposited fibers is formed on the wall 5 of the suction mold 4.

[0059] When a sufficient amount of fiber has been deposited on the wall 5 of the suction mold 4, the suction mold 4 is removed from the pulp basin 14, brought into a removal position and opened, as shown in Figure 5.

[0060] In the removal position, the formed hollow body 1 is removed from the opened suction mold 4 at the first holder 8 and transferred into a transfer mold 17 complementary to the hollow body 1. The transfer mold 17 has a shape that is essentially identical to the suction mold part 4b. In particular, the transfer mold 17 also has a recess complementary to the first holder 8. For the purpose of transferring the hollow body 1 from the suction mold 4 to the transfer mold 17, the transfer mold 17 is positioned in front of the suction mold opening 7 in a mirror-symmetrical manner to the suction mold part 4b. The first holder 8 is then pivoted about the pivot axis of the shaft 10 so that the hollow body 1 and the connecting element 3 come to rest in the transfer mold 17. In the example shown in Figure 5, the pivot angle is approximately 180°. During pivoting, the hollow body 1 rests against the holder 8 and in particular against its second section 8b.The wet and poorly dimensionally stable hollow body 1 can thus be mechanically stabilized, so that it deforms only slightly despite its low dimensional stability. When the hollow body 1 and the connecting element 3 are in the transfer mold 17, the first holder 8 is arranged partially with the fiber molded body in the transfer mold 17 and partially outside the transfer mold 17. It protrudes through the recess in the transfer mold 17.

[0061] In a next step, the transfer mold 17 is moved along the longitudinal axis of the first holder 8 by a conveyor device 18, as shown in Figure 6. In Figures 5 to 7, the conveyor device 18 is designed as a conveyor belt. During the movement of the transfer mold 17, the hollow body 1 and the connecting element 3 are withdrawn from the first holder 8. The design of the second section 8b as a curved perforated sheet enables a good supporting effect. The holder 8 can also have a grid-like structure remote from the first section 8a, as long as it is ensured that it supports the hollow body 1.

[0062] The conveyor belt 18 is part of a continuous furnace 19 known from the prior art, through which the hollow body 1 and the connecting element 3 are moved in the transfer mold 17. The heat generated by the continuous furnace 19 reduces the water content of the hollow body 1 through evaporation. While the hollow body 1 is being dried in the continuous furnace 19, the rotating shaft 15 with the attached suction mold 4 and the first holder 8 continues to rotate and is returned to the beginning of the process to produce another fiber molded body.

[0063] After the hollow body 1 and the connecting element have passed through the continuous furnace 19, they are transferred to a split and opened press mold 20, in which the hollow body 1 with the connecting element 3 arranged thereon is further compacted.

[0064] In Figure 7, the hollow body 1 and the connecting element 3 are shown arranged in the open mold 20. The transfer of the hollow body 1 and the connecting element 3 from the transfer mold 17 into the mold 20 can be carried out using a transfer device 21, which can suck in or grip the hollow body 1 and can be moved between the transfer mold 17 after passing through the continuous furnace 19 and the position in which the mold 20 receives the hollow body 1.

[0065] The compression mold 20 can have two or more compression mold parts 20a, 20b. In the closed state, a wall of the compression mold parts 20a, 20b encloses a second cavity, which is designed essentially complementarily to the hollow body 1. Smaller pores are introduced into the wall of the compression mold 20 than in the suction mold 4, so that the compaction of the hollow body 1 in the compression mold 20 leads to a smooth surface of the hollow body 1. The pores in the wall of the compression mold are fluidly connected to one another and to a second suction device (not shown) via second suction channels 22. The compression mold 20 further has a compression mold opening in a contact region of the compression mold parts 20a, 20b, which opening is designed complementarily to the connection element 3 on the hollow body 1. As intended, the connecting element 3 arranged on the hollow body 1 comes to lie in the press mold opening so that the opening 2 of the hollow body 1 is aligned with the press mold opening.

[0066] Once the hollow body 1 is arranged as intended in a press mold part 20a, the press mold 20 is closed. Subsequently, a second holder 23 with a pressing tool 24 arranged thereon is introduced through the opening 2 in the connecting element 3 into the interior volume of the hollow body 1, as shown in Figure 8. The second holder 23 has a fluid line tightly connected to the pressing tool 24. The pressing tool 24 is formed from an expandable elastomer and tightly connected to the second holder 23 and the fluid line. The pressing tool 24 thus forms an inflatable balloon within the press mold 20. The fluid line feeds a fluid at excess pressure into the pressing tool 24. The fluid line can be connected to a compressed air connection if the supplied fluid is air. Alternatively, a liquid from a compressor or a pump can be fed into the pressing tool 24.Using a liquid, the pressing tool 24 can build up a higher pressure within the pressing mold 20. Figure 9 shows the pressing tool 24 in the expanded form.

[0067] Due to the isostatic pressure of the fluid in the pressing tool 24 and the elasticity of the pressing tool 24, the hollow body 1 is pressed evenly against the wall of the pressing mold 20, thereby compacting, dewatering, and solidifying it. This also solidifies the connection between the wall of the hollow body 1 and the connecting element 3. At the same time, the surface of the wall is imprinted on the hollow body 1.

[0068] The water escaping from the hollow body 1 during compaction is sucked away via the pores in the wall of the compression mold 20 and the second suction channels 22. After a predetermined time, or when a predefined amount of water has been removed from the hollow body 1, the fluid is drained from the compression tool 24, causing the elastic compression tool 24 to contract and assume its original shape, shown in Figure 8. The compression tool 24 can then be removed from the hollow body 1 together with the second holder 23 from the opening 2, and the compression mold 20 is opened.

[0069] Subsequently, the hollow body 1 and the connecting element 3 are removed from the mold 20 by means of the aforementioned transfer device 21 and transferred to a coating station shown in Figure 10. The coating station includes an injector 25 that can be inserted through the opening 2 for filling the interior volume of the hollow body 1 with a coating solution. The coating solution can, in particular, be biodegradable and / or food-safe. The hollow body 1 is filled with a predetermined amount of the coating solution by means of the injector 25. The hollow body 1 is oriented such that the coating solution cannot flow out of the interior volume again.

[0070] Once the hollow body 1 is filled with the predetermined amount of coating solution, the hollow body is rotated by a rotation device 26 about an axis coaxial with the opening 2. In Figure 10, the rotation device 26 is designed as an inclined plane along which the hollow body 1 rolls. If the hollow body 1 is not itself rotationally symmetrical, it can be inserted into a hollow cylinder that can roll along the inclined plane. By rotating it, the entire inner surface of the hollow body 1 is wetted with the coating solution. Excess coating solution is then poured off. For this purpose, the hollow body 1 can be picked up by the transfer device 21 and aligned with the opening 2 facing downwards.

[0071] As an alternative to rotating the hollow body 1 by rolling along an inclined plane, the hollow body 1 can also be gripped by a gripping device in a horizontal orientation of its longitudinal axis and the gripping device can be rotated.

[0072] In this orientation, the coated hollow body 1 is transferred from the transfer device 21 to a drying station shown in Figure 11. The drying station has a rod-shaped heating device 27, onto which the hollow body 1 is pushed through the opening 2. Infrared radiation is activated in the hollow body 1, which cures the coating solution and completely dries the hollow body 1. The heating device 27 is thus designed as a radiant heat source.

[0073] The process is completed when the hollow body 1 has been completely dried and is transferred from the drying station to a storage area.

[0074] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0075] 1 Hollow body 2 Opening 3 Connecting element 4 Suction mold 4a, 4b Suction mold parts 5 Wall of the suction mold 6 Cavity 7 First mold opening 8 First holder 9 First suction channels 10 Shaft 11 Feeding device 13 Pulp 14 Basin 15 Rotating shaft 17 Transfer mold 18 Conveying device, conveyor belt 19 Continuous furnace 20 Press mold 20a, 20b Press mold parts 21 Transfer device 22 Second suction channels 23 Second holder 24 Press tool 25 Injector 26 Rotating device, inclined plane 27 Radiant heat source, rod-shaped heating device

Claims

A method for producing a container with a hollow body (1) made of fibrous material having an opening (2) and a connecting element (3) arranged on the hollow body and surrounding the opening (2), the method comprising the following process steps: providing a split suction mold (4) with a porous wall (5) which, in the closed state, encloses at least one cavity (6) with a mold opening (7); arranging the connecting element (3) on a holder (8) and inserting the holder (8) into the cavity (6) of the suction mold (4) such that the holder (8) extends through the mold opening (7) and holds the connecting element (3) in the mold opening (7); closing the split suction mold (4) and drawing in fibrous material from a pulp (13) through the wall (5) of the suction mold (4) so ​​that the hollow body (1) is formed between the holder (8) and the wall (5); compacting the formed hollow body (1) with attached connecting element (3);and drying of the hollow body (1); characterized in that the hollow body (1) is removed from the split suction mold (4) at the holder (8). Method according to claim 1, characterized in that the holder (8) is hollow and the pulp (13) flows through the holder (8) into the cavity (6) of the suction mold (4). Method according to claim 1 or 2, characterized in that the hollow body (1) is transported on the holder (8) into a transfer form (17) complementary to the hollow body (1) or a split press form (20). Method according to one of the preceding claims, characterized in that the holder (8) is pivoted for the removal of the hollow body (1) from the split suction mold (4) about a section of the holder (8) projecting out of the cavity (6). Method according to one of the preceding claims, characterized in that the hollow body (1) is compressed in the suction mold (4) and / or the compression mold (20). Method according to claim 5, characterized in that the hollow body (1) is compacted by expanding an expandable pressing tool (24) inserted into the hollow body (1). Method according to one of the preceding claims, characterized in that the hollow body (1) is dried from the inside by means of radiant heat and / or a hot air stream. Method according to one of the preceding claims, characterized in that the connecting element (3) is injection molded, cured and pushed onto the holder (8). Method according to one of the preceding claims, characterized in that the hollow body (1) is pre-dried in an oven (19) before compaction. Method according to one of the preceding claims, characterized in that the hollow body (1) is coated on the inner surface with a biodegradable coating solution. Method according to claim 10, characterized in that the coating of the inner surface is carried out by filling the coating solution into the hollow body (1), wetting the inner surface by rotating the hollow body (1) and pouring out excess coating solution. Device for producing a container according to a method according to one of the preceding claims, comprising a basin (14) for a pulp (13); a split suction mold (4) with at least one cavity (6) and a porous wall (5) surrounding the cavity (6); a first holder (8) movable into the split suction mold (4); a suction device and a feed device (11) for an annular connecting element (3) to the first holder (8). Device according to claim 12, characterized in that it comprises at least one of the following features: a transfer mold (17); an oven (19); a transfer device (21); a split press mold (20); a second holder (23) with an expandable press tool (24) that can be inserted into the split press mold (20); a compressor; an injector (25) for a coating solution; a rotary device (26); a radiant heat source (27).

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