DE102022105316A1 - Method and device for producing a biodegradable hollow body with a connection element - Google Patents

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 invention is based on the object of providing a method with a short process duration and a low energy input. To achieve the object, the method comprises the following method steps: - providing a divided 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 connection element ( 3) on a holder (8) and introducing the holder (8) into the cavity (6) of the suction mold (4) in such a way that the holder (8) protrudes through the mold opening (7) and the connecting element (3) in the mold opening ( 7);- closing the split suction mold (4) and sucking fibrous material from a pulp (13) through the wall (5) of the suction mold (4) so that a hollow body (1) is between the holder (8) and the wall (5) is formed;- compression of the hollow body (1) with the connection element (3) arranged thereon; and drying the hollow body (1).

Description

The invention relates to a method for producing a container with a hollow body made of fibrous material having an opening and a connection element arranged on the hollow body and surrounding the opening according to claim 1, in particular a method based on the fiber casting method. The invention also relates to a device for producing a container according to claim 12.

Molded fiber bodies, called molded pulp in English, are used for various purposes, in particular as transport packaging and as molded inserts in packaging to protect sensitive goods. With the aim of further reducing the amount of plastic waste caused by packaging material, the use of fibrous moldings for containing cosmetic products and food products has also received increased attention. In particular, the aim is to use hollow bodies made of fibrous material with a closable opening as jars for cosmetic products, such as creams, or as containers for food products, such as liquids. Achieving suitable mechanical properties and manufacturing pose challenges for such hollow bodies made of fibrous material.

Achieving suitable mechanical properties is particularly important in the area of the opening of the hollow body. Since the opening for using the hollow body for cosmetic products and food products must be able to be closed tightly, sealing foils 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 required so that the closures do not come loose in an uncontrolled manner. A permanent 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 attaching or screwing on the cap. This requires high strength of the caps and the area where a cap is placed, which is why the pulp is regularly reinforced.

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 that reinforces the area of the opening. In practice, the connecting element of such a container can be formed from a polymer in an injection molding process and have a higher strength, higher hardness and/or smoother surface suitable for the adhesion of sealing foils than the fibrous material of the hollow body. A closure can thus be easily attached to the connecting element, which closure securely closes the opening of the hollow body (or of the container). The connection element can also have special structural details such as an external thread with which an internal thread of a closure designed as a screw closure interacts. The applicant has developed a thermoplastic material that consists exclusively of biodegradable or bioinert components. If the connection element and the closure of a container are formed from biodegradable biopolymers, the entire container can be biodegradable.

Up to now, the production of these containers has been complex. In the case of production processes known from the prior art, the molded fiber body is first produced by means of a fiber casting process. The connecting element is manufactured separately and connected to the dried fiber body in a form-fitting or material-fitting manner. Alternatively, the connection element can be injection molded onto the dried fiber body.

For example disclosed EP 1 221 413 A1 a container having a fiber molded article having on its inner surface and/or outer surface a resin layer formed by applying a coating to produce a certain thickness ratio of the resin layer to the molded article, and the inner and outer surfaces having a center-line average roughness (Ra ) from 0.5 to 20 µm. The fibrous body is formed in a multi-step process. First, pulp is poured into a cavity of a split mold. The water of the pulp is sucked out through mesh-covered holes in the wall of the split mold, thereby forming the fibrous body on the wall. An elastic and expandable pressing tool is then introduced into the cavity of the fiber molded body and expanded in order to dewater and compact the fiber molded body. After compression of the molded fiber body, the pressing tool contracts again and is removed. The split mold is opened to remove the wet fiber body. The fiber molding is then pre-dried, coated and finally dried. Optionally, the container has a connection element with 40 to 90% by weight of natural fibers and a binder. The attachment of the connection element to the fiber body is not described in detail.

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

The object of the invention is to provide a method and a device which enable the efficient production of a container as described above. In particular, the method should enable a short process duration and a low energy input, and produce a reliable connection between the connection element and the hollow body.

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.

• - Bereitstellen einer geteilten Saugform mit einer porösen Wandung, welche in geschlossenem Zustand mindestens einen Hohlraum mit einer Saugformöffnung umschließt;
• - Anordnen des Anschlusselements an einem Halter und Einbringen des Halters in den Hohlraum der Saugform derart, dass der Halter die Saugformöffnung durchragt und das Anschlusselement in der Saugformöffnung hält;
• - Schließen der geteilten Saugform und Ansaugen von Fasermaterial aus einer Pulpe durch die Wandung der Saugform, so dass ein Hohlkörper aus Faserstoff zwischen dem Halter und der Wandung gebildet wird;
• - Verdichten des gebildeten Hohlkörpers mit daran angeordnetem Anschlusselement; und
• - Trocknen des Hohlkörpers.

The process described here for manufacturing a container includes the following process steps:

• - Providing a divided suction mold with a porous wall which, in the closed state, encloses at least one cavity with a suction mold opening;
• - arranging the connecting element on a holder and introducing the holder into the cavity of the suction mold in such a way that the holder protrudes through the suction mold opening and holds the connecting element in the suction mold opening;
• - closing the divided suction mold and sucking fibrous material from a pulp through the wall of the suction mold so that a hollow body of fibrous material is formed between the holder and the wall;
• - Compressing the hollow body formed with the connection element arranged thereon; and
• - Drying of the hollow body.

The divided suction mold is composed of several suction mold parts, in particular two halves. The hollow fiber molded body is formed in the closed state of the suction mold 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 a pulp can be sucked. This inner surface can be realized in a conventional manner by a suction mold, which has a largely solid base body made of plastic or metal, into which a screen body is inserted to form the porous inner wall. However, it is also possible to produce the parts of the suction mold, e.g. with additive manufacturing techniques in 3D printing, with fluid channels being 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 split suction mold further includes at least one suction mold opening which connects the cavity to an environment outside of 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 circumference that can be divided. Features of the method that affect the formation of the suction mold opening are described below.

A holder is provided for the method according to the invention, on which a connection element is arranged. The holder is an elongate body which has at least a portion with a cross-section which depends on the shape of the opening of the container to be manufactured. For example, the cross section can be round if the opening of the container is to be round. If the opening is square, said cross-section of the holder has a square shape. Likewise, in the case of an oval or other non-round 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 that is assigned to the opening of the container to be produced. The areas of the holder remote from the opening of the container to be produced can have any deviating cross-section. The connecting element can be arranged on the holder by means of a feeding device, the feeding device placing the connecting element in a predetermined position on the holder. The feeding 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 area of the opening of the container to be produced.

The holder and the connection element arranged on it are introduced together into the suction mold. The connection element is arranged in the suction mold opening and the holder protrudes through the suction mold opening in such a way that it is arranged partially in the cavity and partially 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 connection element can be inserted into the opened suction mold and the mold parts can then be closed. If the suction mold opening is not formed in a contact area of at least two suction mold parts, the holder with the connection element can be moved in the longitudinal direction of the holder through the suction mold opening be inserted into the suction mold until the connection element lies in the suction mold opening. At least one section of the suction mold opening can be somewhat larger than the connecting element. 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.

After the holder and the connecting element have been placed in the suction mold opening, the split suction mold is closed and a pulp is sucked into the cavity by immersing the suction mold and/or the holder in a basin filled with pulp. The holder can be hollow so that the pulp is 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 recyclable fibers, but also fresh fibers, depending on the requirements for the optical properties of the fiber molded body. The pulp can contain other additives that have a positive effect on the properties of the molded fiber body.

The pores in the porous wall of the suction mold are designed in such a way that the water penetrates the pores and the fibrous material is deposited on the wall when the pulp is sucked. The wall thickness of the hollow body formed increases as the duration of suction increases. In particular, a fiber layer forms between the wall of the suction mold and the holder, in which the connection element is embedded. The fiber layer of the hollow body and the connecting element are connected in a form-fitting manner. The connecting element can have a connecting wall with openings, which extends approximately parallel to the porous wall. The connecting wall, for example made of injection-moulded thermoplastic, can have a wall thickness of the order of 1 mm and openings with a clear area of, for example, 20 mm ² . If the connection element surrounds an opening of the container, the connecting wall can extend along the opening in the form of a ring and have a width (wall thickness) of approx. 5 to 15 mm. The fibers deposited on the wall form a layer which breaks through the openings in the connecting wall and in this way embeds the connecting wall. The connection element is thus firmly anchored in the fiber layer.

As soon as a sufficient quantity of fibrous material has been deposited in the cavity of the suction mold and/or a predetermined time has elapsed for the suction of fibrous material to take place, the formed hollow body is compacted with the connection element arranged thereon. Compacting means that the water contained in the molded fiber body is mechanically removed from the molded fiber body. For this purpose, a relative overpressure can be generated in the interior 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 fibrous material to be deposited on the porous wall. Compressing the molded fiber body increases its mechanical stability and makes it easier to handle the molded fiber body. However, an expandable pressing tool, described further below, can also mechanically press the moisture out of the fiber layer already formed in the suction mold.

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

The container produced in this way can, for example, be filled with a free-flowing product, in particular a cream or a drink. The opening of the container can then be provided with a closure that is tightly connected to the connection element.

The method described above has a number of advantages. The connection element can be positioned very precisely and quickly in the suction mold opening by means of the holder. Furthermore, by forming the fibrous material layer of the hollow body around the connection element, a particularly strong connection can be achieved between the connection element and the hollow body. Because the pulp has a low viscosity and can therefore even penetrate into filigree geometric configurations (e.g. undercuts or openings in a connecting wall) of the connecting element and dry and harden there.

In practice the holder can be hollow and the pulp can flow through the holder into the cavity of the suction mold. As a result, the entire inner cross-section of the hollow holder is available for the pulp to flow into the suction mold and enables the suction mold to be filled quickly and completely.

In a further practical embodiment of the method, the hollow body can be removed from the divided suction mold on the holder and transported into a transfer mold complementary to the hollow body or into a divided compression mold. In other words, the hollow body can be transported from the suction mold directly into the compression mold that is complementary to it. Alternatively, he can Hollow bodies are transported from the suction mold into the transfer mold, which is complementary to it, and from there into the compression mold, which is also complementary. Details of the transfer mold and the press mold are described below. The removal of the hollow body from the suction mold and the transport of the hollow body located on the holder enable the hollow body to be positioned accurately and quickly in the transfer mold or the compression mold. The holder also enables the hollow body to be removed and transported safely, ie without damage, because the holder can mechanically support the hollow body. Because when the holder with the hollow body is moved out of the divided suction mold, the hollow body is deposited with a region on the holder. A particularly safe removal and transport are possible if the holder supports the hollow body essentially over the entire length, for example if the holder protrudes into the hollow body up to its bottom.

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.

The removal and transport of the hollow body on the holder is particularly quick and easy in practice if the holder is pivoted about an axis lying outside the cavity for transport into the transfer mold or the divided compression mold. For this purpose, the holder can project out of the cavity, one end of the section projecting out of the cavity being pivotably mounted about a pivot axis formed transversely to the longitudinal direction of the holder. After the divided 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 divided suction mold into a transfer mold or the opened, divided compression mold. After the holder is 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.

In practice, the hollow body can be compacted in the suction mold and/or in the compression mold. Compression in the suction mold makes it easier to remove the hollow body, which is very wet without compression, from the suction mold. However, it is possible that the pores and structures in the wall of the suction mold are reproduced in the surface of the hollow body. In addition to the compression in the suction mold or as an alternative to this, the hollow body can therefore be compressed in a compression mold specially provided for this purpose. For this purpose, the hollow body is transported from the suction mold into the compression mold.

The split die is formed of a plurality of die parts. In the closed state, the compression mold has a wall that is designed to be essentially complementary to the hollow body and the connection element. Furthermore, the mold has a mold opening which is aligned with the opening of the hollow body arranged in the mold. The wall of the compression 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 press mold can also include a suction channel which is fluidly connected to the interior of the press mold and through which water can be discharged. The hollow body can be placed in the opened mold and removed from it after pressing. When the hollow body is arranged in the closed compression mold, the wall of the compression mold encloses the hollow body and the internal pressure in the interior volume of the hollow body is increased by a compression tool, so that the hollow body is compressed. In this case, excess water preferably flows out of the hollow body through the suction channel.

In practice, the hollow body can be compacted by expanding an expandable compression tool inserted into the hollow body when the hollow body is within the die. In this way, the hollow body is drained quickly and efficiently, and it receives the desired surface structure both on the inside through the pressing tool and on the outside through the inner surface of the wall of the press mold.

In practice, the expandable pressing tool can consist of a bladder or a balloon made of an elastomer or another rubber-elastic material and be arranged on a second holder which can be inserted in particular through the press mold opening into the inner volume of the hollow body arranged in the press mold. The second holder has a fluid line that is tightly connected to the pressing tool and can be closed, through which a fluid can be pressed at overpressure into the interior of the pressing tool. For example, water, oil, air, industrial gases or a mixture of the above fluids can be used as the fluid.

To compress the hollow body with the pressing tool in the pressing mold, the second holder is inserted into the inner volume of the hollow body and the pressing tool expands by forcing in the fluid, with the pressing tool expanding like a balloon, resting against the inner surface of the hollow body and pressing it against the wall of the mold presses. The isostatic fluid pressure leads to a uniform compression of the wall of the hollow body. After a predetermined pressing time or a predetermined drainage of the hollow body, the fluid is drained through the fluid line from the pressing tool, causing it to contract again, and the pressing tool is pulled out of the container with the second holder.

It is also possible to compact the hollow body with the pressing tool in the suction mold. For this purpose, the first holder can be pulled out through the suction mold opening in the closed state of the suction mold and the second holder can be pushed into the hollow body through the suction mold opening. Compaction then takes place in the same way as compaction in a die. Alternatively, the pressing tool can also be arranged on the holder that carries the connection element.

In practice, the hollow body can be dried from the inside by means of radiant heat and/or a stream of hot air. For this purpose, a rod-shaped heating device can be inserted through the opening of the hollow body. The heating device can be activated in the hollow body and emit infrared radiation, UV radiation and/or microwave radiation there. Additionally or alternatively, a stream of hot air can exit through the rod-shaped heating device, which flows along the inner surface of the hollow body and exits the hollow body through the opening into the environment. Drying the hollow body removes residual moisture from the fiber material. As a result, optional coatings can solidify on the inner surface of the hollow body. Details on the application of optional coatings are given below.

In practice, the connection element can be injection molded from a thermoplastic and pushed onto the holder in the hardened state. Injection-moulded connection elements made of thermoplastic can be designed geometrically freely, i.e. with only a few structural limitations. Such a connection element can have, for example, a lattice-shaped jacket section with openings, which forms a connecting wall and is arranged in the area of the opening of the container. The connecting wall has openings through which the fiber material of the hollow body penetrates.

In a further practical embodiment of the method, the hollow body can be pre-dried in an oven before being compressed. In this case, the hollow body can be located in a part of the compression mold or the transfer mold that is transported through the furnace. Or the hollow body can be placed on a conveyor belt that transports it through the furnace. By pre-drying, the water content of the hollow body can already be reduced before compaction. The furnace can in particular be a continuous furnace. Due to the reduced residual moisture in the hollow body, greater dimensional stability of the hollow body is achieved in the subsequent compression step.

In another practical embodiment, the hollow body can also be coated on the inner surface with a biodegradable coating solution. For the coating of the inner surface, a pipeline that is fluidly connected to a supply of a coating solution can be inserted through the opening of the container into the inner volume of the hollow body. The coating solution can then be introduced into the interior volume through the tubing. This allows a coating to be created that is suitable for contact with food or with liquids. If coating is done after compaction and before final drying, the coating can be particularly tough.

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

• - ein Becken für eine Pulpe;
• - eine geteilte Saugform mit mindestens einem Hohlraum und einer den Hohlraum umgebenden porösen Wandung;
• - einen in die geteilte Saugform bewegbaren ersten Halter;
• - eine Saugvorrichtung und
• - eine Zuführvorrichtung für ein ringförmiges Anschlusselement zum ersten Halter.

The invention also relates to a device for producing a container according to one of the above-described embodiments of the method. The device includes

• - a tank for a pulp;
• - A divided suction mold with at least one cavity and a cavity surrounding the porous wall;
• - a movable in the split suction mold first holder;
• - a suction device and
• - a feeding device for a ring-shaped connecting element to the first holder.

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

• - eine Transferform;
• - einen Ofen;
• - eine Transfervorrichtung;
• - eine geteilte Pressform;
• - einen in die geteilte Pressform einbringbaren zweiten Halter mit einem expandierbaren Presswerkzeug;
• - einen Injektor für eine Beschichtungslösung;
• - eine Rotationsvorrichtung;
• - eine Strahlungswärmequelle.

In practice, the device may also include at least one of the following features:

• - a transfer mold;
• - an oven;
• - a transfer device;
• - a split die;
• - A second holder which can be introduced into the split mold and has an expandable pressing tool;
• - an injector for a coating solution;
• - a rotation device;
• - a radiant heat source.

• 1 eine dreidimensionale Teilansicht einer erfindungsgemäßen Vorrichtung mit einer Mehrzahl von Saugformen und Halteren;
• 2 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 1 mit auf den Halteren befindlichen Anschlusselementen;
• 3 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 1 und 2 mit in den Saugformen angeordneten Halteren;
• 4 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 3 mit den Saugformen in einem Pulpebecken;
• 5 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 4 mit Hohlkörpern und Transferformen an den Saugformen;
• 6 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 5 mit den Transferformen und den Hohlkörpern in einem Durchlaufofen;
• 7 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 6, bei der sich die Hohlkörper in Pressformen befinden;
• 8 eine isolierte dreidimensionale Ansicht eines Hohlkörpers in einer Pressform mit einem Presswerkzeug;
• 9 eine isolierte dreidimensionale Ansicht eines Hohlkörpers in einer Pressform mit einem expandierten Presswerkzeug;
• 10 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 7 mit Injektoren zum Beschichten der Hohlkörper;
• 11 eine weitere dreidimensionale Teilansicht der Vorrichtung aus 8 mit einer Trocknungsvorrichtung für die Hohlkörper.

Further practical embodiments and advantages of the invention are described below in connection with the drawings. Show it:

• 1 a three-dimensional partial view of a device according to the invention with a plurality of suction molds and holders;
• 2 Another three-dimensional partial view of the device 1 with connecting elements located on the holders;
• 3 Another three-dimensional partial view of the device 1 and 2 with holders arranged in the suction molds;
• 4 Another three-dimensional partial view of the device 3 with the suction molds in a pulp basin;
• 5 Another three-dimensional partial view of the device 4 with hollow bodies and transfer molds on the suction molds;
• 6 Another three-dimensional partial view of the device 5 with the transfer molds and the hollow bodies in a continuous furnace;
• 7 Another three-dimensional partial view of the device 6 , in which the hollow bodies are in molds;
• 8th an isolated three-dimensional view of a hollow body in a mold with a pressing tool;
• 9 an isolated three-dimensional view of a hollow body in a compression mold with an expanded compression tool;
• 10 Another three-dimensional partial view of the device 7 with injectors for coating the hollow bodies;
• 11 Another three-dimensional partial view of the device 8th with a drying device for the hollow bodies.

The 1 until 9 show the sequence of the method according to the invention and a device for carrying out the method. A device can be seen in the figures, with which ten containers can be produced simultaneously. It is pointed out that a method and the device according to the invention are not limited to the simultaneous production of ten containers. Rather, the number of containers produced at the same time can be adapted to the requirements. In the following, the production is described using the example of a single container, which runs simultaneously in the molds. In the 1 until 11 the same components are provided with the same reference numbers.

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 divided suction mold 4 with a porous wall 5 is first provided. The suction mold 4 is rotationally symmetrical and is divided into two suction mold parts 4a, 4b along its central longitudinal plane. The suction mold parts 4a, 4b are connected to one another at a first end so as to be pivotable about a pivot axis and can be swung open along the pivot axis. In the closed state, the suction mold parts 4a, 4b enclose with their inner wall 5 a cavity 6 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) which 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 led to the 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 pipes which are attached to the suction mold part 4a and carry the suction mold 4.

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

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 designed as a hollow cylinder and the second section 8b, which protrudes from the first section 8a, is designed as a bent perforated plate and extends over part of the circumference of the first section 8a. The second section 8b is connected in one piece or at least seamlessly to the first section 8a and both sections 8a, 8b have the same curvature. The first holder 8 is thus an elongate body which, by means of a shaft 10 oriented transversely to the longitudinal direction of the first holder 8 , is arranged so that it can pivot in a receptacle for the shaft 10 which is fastened to the suction mold 4 . The first holder 8 can from the 1 and 2 shown position outside of the suction mold 4 in the position of 3 be pivoted, in which it extends through the suction mold opening 7 into the interior of the suction mold 4. It then protrudes through almost the entire cavity 6 of the suction mold 4.

The first holder 8 is in the vertical orientation of the 1 in front of the suction mold opening 7 and below a feeding device 11 for feeding an annular connecting element 3 to the first holder 8. The feeding device 11 can, for example, have a tube which is open at at least one end and in which one or more connecting elements 3 are accommodated. The connection element 3 is formed from an injection molded and biodegradable thermoplastic in the form of a hardened ring. As in the 1 and 2 can be seen, the pipe with the pipe opening can be moved over the free end of the second section 8b of the first holder 8 and thereby push a connection element 3 onto the first holder 8 up to the first section 8a. The cross-sectional shape of the tube, the first portion 8b of the first holder 8 and the suction mold opening 7 are complementary to each other and may deviate from the circular shape illustrated in the drawings. They depend in particular on the shape of the opening of the container to be produced.

After the connection element 3 is arranged on the first portion 8a of the first holder 8, the tube of the feeding 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 in 3 is shown. The suction mold 4 is then closed by folding the suction mold parts 4a, 4b together. The first holder 8 protrudes through the suction mold opening 7 and holds the connecting element 3 in the suction mold opening 7 with the first section 8a in such a way that a gap is formed between the connecting element 3 and the suction mold opening 7 .

The closed suction mold 4 with the first holder 8 located therein is immersed in a tank 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 creates a negative pressure and sucks water. This negative pressure is passed through the tubular suction channels 9 made of stainless steel to the wall 5 of the suction mold 4. All the suction molds 4 connected to the rotary shaft 15 via the suction channels 9 are moved through the pulp basin 14 when the rotary shaft 15 is rotated.

In the process, 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 fibrous 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. On the wall 5 of the suction mold 4 a Hollow body 1 formed from deposited fibers.

When a sufficient amount of pulp has been deposited on the wall 5 of the suction mold 4, the suction mold 4 is removed from the pulp basin 14, brought to a removal position and opened, as in FIG 5 is shown.

In the removal position, the hollow body 1 formed is removed from the opened suction mold 4 on the first holder 8 and transferred to a transfer mold 17 complementary to the hollow body 1 . The transfer mold 17 has a shape substantially identical to the suction mold part 4b. In particular, the transfer mold 17 also has a recess designed to complement 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 mirror-symmetrically to the suction mold part 4b in front of the suction mold opening 7. The first holder 8 is then pivoted about the pivot axis of the shaft 10 so that the hollow body 1 and the connection element 3 come to rest in the transfer mold 17 . in the in 5 example shown, the swivel angle is approx. 180°. During the pivoting, the hollow body 1 rests against the holder 8 and in particular against its second section 8b. The wet and less dimensionally stable hollow body 1 can be mechanically stabilized so that it deforms only slightly despite its low dimensional stability. If the hollow body 1 and the connecting element ment 3 are in the transfer mold 17, the first holder 8 is partially arranged with the fiber molded body in the transfer mold 17 and partially outside of the transfer mold 17. It protrudes through the recess in the transfer mold 17.

In a next step, the transfer mold 17 is moved with a conveyor 18 along the longitudinal axis of the first holder 8, as in FIG 6 shown. In the 5 until 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 connection element 3 are pulled off the first holder 8 . The formation of the second section 8b as a curved perforated plate enables a good supporting effect. The holder 8 can also have a lattice-like structure remote from the first section 8a as long as it is ensured that it supports the hollow body 1 .

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 in the transfer mold 17 are moved. The heat generated by the continuous furnace 19 causes a reduction in 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 suction mold 4 attached thereto and the first holder 8 is further rotated and fed again to the beginning of the process in order to produce another fiber molded body.

After the hollow body 1 and the connection element have passed through the continuous furnace 19, they are transferred to a divided and opened compression mold 20, in which the hollow body 1 with the connection element 3 arranged thereon is further compressed.

In 7 the hollow body 1 and the connection element 3 are shown arranged in the opened mold 20 . The hollow body 1 and the connection element 3 can be transferred from the transfer mold 17 to the press mold 20 with a transfer device 21, which can suck or grip the hollow body 1 and 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, can be moved.

The mold 20 may have two or more mold parts 20a, 20b. In the closed state, a wall of the compression mold parts 20a, 20b encloses a second cavity, which is designed to be essentially complementary 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 compression 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) through second suction channels 22 . The compression mold 20 also has a compression mold opening in a contact area of the compression mold parts 20a, 20b, which is designed to complement the connecting element 3 on the hollow body 1. As intended, the connection element 3 arranged on the hollow body 1 comes to rest in the press mold opening, so that the opening 2 of the hollow body 1 is aligned with the press mold opening.

When the hollow body 1 is arranged as intended in a press mold part 20a, the press mold 20 is closed. A second holder 23 with a pressing tool 24 arranged on it is then inserted through the opening 2 in the connection element 3 into the inner volume of the hollow body 1, as shown in FIG 8th shown. The second holder 23 has a fluid line that is tightly connected to the pressing tool 24 . The pressing tool 24 is formed from an expandable elastomer and is tightly connected to the second holder 23 and the fluid line. The pressing tool 24 thus forms an inflatable balloon within the pressing mold 20. The fluid line feeds a fluid with excess pressure into the pressing tool 24. The fluid line can be connected to a compressed air connection if the fluid supplied is air. Alternatively, a liquid can be fed into the pressing tool 24 from a compressor or a pump. With a liquid, a higher pressure can be built up within the compression mold 20 by the compression tool 24 . 9 shows the pressing tool 24 in the expanded form.

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 and is thereby compressed, drained and solidified. This also strengthens 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 impressed on the hollow body 1.

The water escaping from the hollow body 1 during compression is sucked off 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 pressing tool 24, so that the elastic pressing tool 24 contracts and its original, in 8th takes the form shown. The pressing tool 24 can then be used together with the second holder 23 are removed from the opening 2 of the hollow body 1 and the mold 20 is opened.

The hollow body 1 and the connection element 3 are then removed from the press mold 20 by means of the aforementioned transfer device 21 and placed in an in 10 shown coating station transferred. In the coating station, an injector 25 that can be inserted through the opening 2 is provided for filling a coating solution into the interior volume of the hollow body 1 . In particular, the coating solution can be biodegradable and/or food-safe. The hollow body 1 is filled with a predetermined quantity of the coating solution by means of the injector 25 . The hollow body 1 is aligned in such a way that the coating solution cannot flow out of the inner volume again.

When the hollow body 1 is filled with the predetermined amount of the coating solution, the hollow body is rotated with a rotation device 26 about an axis coaxial with the opening 2 . In 10 the rotation device 26 is designed as an inclined plane along which the hollow body 1 rolls. If the hollow body 1 itself is not designed to be rotationally symmetrical, it can be inserted into a hollow cylinder which can roll along the inclined plane. By rotating 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 with the transfer device 21 and aligned with the opening 2 downwards.

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 with its longitudinal axis aligned horizontally and the gripping device can be rotated.

In this orientation, the coated hollow body 1 is transferred from the transfer device 21 to an in 11 shown drying station. 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 hardens the coating solution and completely dries the hollow body 1. The heating device 27 is thus designed as a radiant heat source.

The process ends when the hollow body 1 has dried completely and is transferred from the drying station to a store.

The features of the invention disclosed in the present description, in the drawings and in the claims can 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 embodiments described. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

Reference List

1

hollow body

2

opening

3

connection element

4

suction mold

4a, 4b

suction moldings

5

wall of the suction mold

6

cavity

7

first mold opening

8th

first holder

9

first suction channels

10

Wave

11

feeding device

13

pulp

14

pool

15

rotary shaft

17

transfer form

18

Conveyor, conveyor belt

19

continuous furnace

20

mold

20a, 20b

molded parts

21

transfer device

22

second suction channels

23

second holder

24

pressing tool

25

injector

26

Rotating device, inclined plane

27

Radiant heat source, rod-shaped heater

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 1221413 A1 [0006]
• EP 1081285 B1 [0007]
• WO 2003/010386 A1 [0007]

Claims (14)

Method for producing a container with a hollow body (1) made of fibrous material and having an opening (2) and a connecting element (3) arranged on the hollow body and surrounding the opening (2), the method comprising the following method steps: - Providing a divided 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 introducing the holder (8) into the cavity (6) of the suction mold (4) in such a way that the holder (8) protrudes through the mold opening (7) and the connecting element (3 ) in the mold opening (7); - Closing the divided suction mold (4) and sucking fiber 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). becomes; - Compressing the formed hollow body (1) with the connection element (3) arranged thereon; and - Drying of the hollow body (1). procedure after 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). procedure after claim 1 or 2 , characterized in that the hollow body (1) is removed from the divided suction mold (4) on the holder (8). procedure after claim 3 , characterized in that the hollow body (1) on the holder (8) is transported into a transfer mold (17) complementary to the hollow body (1) or into a divided compression mold (20). procedure after claim 3 or4, characterized in that the holder (8) for removing the hollow body (1) from the divided suction mold (4) is pivoted about a section of the holder (8) protruding from 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). procedure after claim 6 , characterized in that the hollow body (1) is compressed by expanding an expandable pressing tool (24) introduced 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 stream of hot air. Method according to one of the preceding claims, characterized in that the connection element (3) is injection molded, hardened and pushed onto the holder (8). procedure after claim 3 , characterized in that the hollow body (1) is pre-dried in an oven (19) before being compressed. 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. procedure after claim 11 , characterized in that the inner surface is coated by filling the hollow body (1) with the coating solution, wetting the inner surface by rotating the hollow body (1) and pouring out excess coating solution. Apparatus for manufacturing a container according to a method according to any one of the preceding claims, comprising - a basin (14) for a pulp (13); - A divided 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 divided suction mold (4); - a suction device and - A feeding device (11) for an annular connecting element (3) to the first holder (8). device after Claim 13 , 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 mold (20); - A second holder (23) which can be introduced into the divided compression mold (20) and has an expandable compression tool (24); - a compressor; - an injector (25) for a coating solution; - a rotation device (26); - a radiant heat source (27).

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