DE102022105316B4 - Method and device for producing a biodegradable hollow body with a connecting element - Google Patents

Abstract

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 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 introducing 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 sucking 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 connecting element (3) arranged thereon; and- drying the hollow body (1), characterized in that the hollow body (1) is removed from the divided suction mold (4) at the holder (8).

Description

The invention relates to a method for producing a container with a hollow body made of fibrous material having an opening and a connecting element arranged on the hollow body and surrounding the opening according to the preamble of 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 this method.

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 aim of further reducing the amount of plastic waste caused by packaging material, the use of molded pulp to contain cosmetic and food products has also attracted increasing attention. In particular, hollow fiber bodies with a sealable opening are being used 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.

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 the use of the hollow body for cosmetic products and food products, sealing films and/or closure caps made of polymers are regularly arranged as closures on the openings. A firm connection of the closures to the hollow body is necessary so that the closures do not come loose uncontrollably. 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 the cap on. This requires a high level of strength of the closure caps and the area where a closure cap is arranged, which is why the fiber material is regularly reinforced.

In order to meet the above requirements, it is known in practice to provide containers as a combination of a fiber molded 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 a higher strength, a higher hardness and/or a smoother surface suitable for the adhesion of sealing films than the fiber material of the hollow body. A closure can thus simply 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 that consists exclusively of biodegradable or bioinert components. If the connecting element and the closure of a container are formed from biodegradable biopolymers, the entire container can be biodegradable.

The production of these containers has so far been complex. In the manufacturing processes known from the state of the art, the fiber molded body is first produced using a fiber casting process. The connecting element is produced separately and connected to the dried fiber body in a form-fitting or material-fitting manner. Alternatively, the connecting element can be molded onto the dried fiber body.

For example, EP 1 221 413 A1 a container with a fiber molded body having a resin layer on its inner surface and/or its outer surface, which is formed by applying a coating, wherein a certain thickness ratio of the resin layer to the molded article is produced and the inner and outer surfaces have an average center line roughness (Ra) of 0.5 to 20 µm. The fiber 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 holes covered with a net in the wall of the split mold, whereby the fiber body is formed on the wall. Then an elastic and expandable pressing tool is inserted into the cavity of the fiber molded body and expanded to dewater and compact the fiber molded body. After the fiber molded body has been compacted, the pressing tool contracts again 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 has a connecting element with 40 to 90 wt.% natural fibers and a binding agent. The attachment of the connecting element to the fiber body is not described in detail.

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

A method according to the preamble of claim 1 is known from the document JP 2001-303 500 A known.

The invention is based on the object of providing 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 time and a low energy input, as well as produce a reliable connection between the connection element and the hollow body, enabling precise and rapid positioning of the hollow body.

According to the invention, this object is achieved by a method having the features of claim 1 and by a device operating according to this method 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 producing a container comprises 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 connection 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 connection 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 of fiber material is formed between the holder and the wall;
• - compacting the hollow body formed with the connecting element arranged thereon; and
• - Drying the hollow body.

According to the invention, the hollow body is removed from the divided suction mold at the holder.

The split suction mold is composed of several suction mold parts, in particular of 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 in. 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 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, 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 also 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 circumference that is divisible. Features of the method relating to the formation of the suction mold opening are described further below.

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-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 which is associated with 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 different cross section. The connection element can be arranged on the holder by means of a feed device, wherein the feed device places the connection element in a predetermined position on the holder. The feed device can, for example, arrange the connection 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.

The holder and the connecting element arranged on it are inserted into the suction mold together. The connecting element is arranged in the suction mold opening and the holder extends through the suction mold opening so that it is partially in the cavity and partially outside the suction form is arranged. 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 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 connection element can be inserted into the suction mold in the longitudinal direction of the holder through the suction mold opening until the connection element lies in the suction mold opening. The suction mold opening can be slightly larger than the connection element, at least in one section. In this case, the connection element can be held in the suction mold opening by the holder in such a way that a gap is formed between the connection element and the suction mold opening.

After the holder and the connecting element have been arranged in the suction mold opening, the split suction mold is closed and a pulp is sucked into the cavity by dipping the suction mold and/or the holder into 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 fiber molded 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 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 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 mm ² , 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 approximately 5 to 15 mm. The fibers deposited on the wall form a layer that breaks through the openings in the connecting wall and embeds the connecting wall in this way. The connecting element is thus firmly anchored in the fiber layer.

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 passed for the suction of fiber material, the hollow body formed is compacted with the connecting element arranged on it. Compacting 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 inner 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 passed 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 the fiber molded body easier to handle. However, an expandable pressing tool described below can also mechanically press the moisture out of the fiber layer 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 be filled with a flowable product, in particular a cream or a drink, for example. The opening of the container can then be provided with a closure which is tightly connected to the connecting 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 using the holder. Furthermore, by forming the fiber layer of the hollow body around the connection element, a particularly strong connection between the connection 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 connection 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. This means that the entire inner cross section of the hollow holder is available for the pulp to flow into the suction mold. and enables quick and complete filling of the suction form.

As mentioned above, the hollow body is removed from the divided suction mold on the holder. The hollow body on the holder can then be transported into a transfer mold that is complementary to the hollow body or 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, the hollow body can be transported from the suction mold into the transfer mold that is complementary to it and from there into the compression mold that is also complementary. 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 the hollow body to be positioned precisely and quickly in the transfer mold or the compression mold. The holder also enables the hollow body to be removed and transported safely, i.e. without damage, because the holder can support the hollow body mechanically. This is because when the holder with the hollow body is moved out of the divided suction mold, one area of the hollow body rests on the holder. Particularly safe removal and transport are possible if the holder supports the hollow body essentially over its entire length, for example if the holder extends 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.

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 outside the cavity for transport into the transfer mold or the split press mold. For this purpose, the holder can protrude from the cavity, with one end of the section protruding from the cavity being pivotably 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 press mold. After the holder has been pivoted and the hollow body is arranged in the transfer mold or the press mold, the transfer mold or the press 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 press mold. Compacting in the suction mold makes it easier to remove 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 as an alternative to this, the hollow body can therefore be compacted in a press mold specially provided for this purpose. For this purpose, the hollow body is transported from the suction mold to the press mold.

The split mold is formed from a plurality of mold parts. In the closed state, the mold has a wall that is essentially complementary to the hollow body and the connection element. The mold also 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. 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 mold, the wall of the mold encloses the hollow body and the internal pressure in the internal volume of the hollow body is increased by a pressing tool so that the hollow body is compressed. Excess water flows out of the hollow body preferably through the suction channel.

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

In practice, the expandable pressing tool can consist of a bladder or a balloon made of an elastomer or other rubber-elastic material and attached to a second A holder can be arranged which can be introduced 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 which is tightly connected to the press tool and can be closed, through which a fluid can be pressed into the interior of the press tool at excess pressure. The fluid used can be, for example, water, oil, air, industrial gases or a mixture of the above fluids.

To compact the hollow body with the pressing tool in the mold, the second holder is introduced into the inner volume of the hollow body and the pressing tool is expanded by pressing in the fluid, whereby the pressing tool expands like a balloon, rests on the inner surface of the hollow body and presses it against the wall of the mold. The isostatic fluid pressure leads to a uniform compaction of the wall of the hollow body. After a predetermined pressing time or a predetermined drainage of the hollow body, the fluid is drained from the pressing tool through the fluid line, 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 when the suction mold is closed 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 pressing mold. 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 using radiant heat and/or a hot air stream. For this purpose, a rod-shaped heating device can be introduced 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. Additionally or alternatively, a hot air stream can emerge 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. By drying the hollow body, residual moisture is removed from the fiber material. Optional coatings can then solidify on the inner surface of the hollow body. Details on the application of optional coatings are explained below.

In practice, the connecting element can be injection-molded from a thermoplastic and pushed onto the holder in a hardened state. Injection-molded connecting elements made from thermoplastic can be designed geometrically freely, i.e. with 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 opening of the container. The connecting wall has openings that are penetrated by the fiber material of the hollow body.

In another practical embodiment of the method, the hollow body can be pre-dried in an oven before compaction. The hollow body can be located in a part of the press mold or the 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 can reduce the water content of the hollow body before compaction. The oven can be a continuous oven in particular. The reduced residual moisture in the hollow body means that the hollow body retains its shape better in the subsequent compaction step.

In another practical embodiment, the hollow body can additionally be coated on the inner surface with a biodegradable coating solution. To coat the inner surface, a pipe fluidly connected to a supply of a 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 pipe. This can produce a coating that is suitable for contact with food or liquids. If the coating is carried out after compaction and before final drying, the coating can be particularly resistant.

Coating the inner surface is particularly easy in practice if the hollow body is rotated after the coating solution has been filled in, 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 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 embodiments of the method described above. The device comprises

• - a basin for a pulp;
• - a split 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.

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 further comprise at least one of the following features:

• - a transfer form;
• - an oven;
• - a transfer device;
• - a split mold;
• - a second holder with an expandable pressing tool that can be inserted into the split pressing mold;
• - 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 conjunction with the drawings.

• 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 tank;
• 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 press moulds;
• 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 mold with an expanded pressing 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 to 9 show the sequence of the method according to the invention and a device for carrying out the method. In the figures, a device can be seen with which ten containers can be produced simultaneously. It should be noted that a method according to the invention and the device are not limited to the simultaneous production of ten containers. Rather, the number of containers produced simultaneously can be adapted to the requirements. In the following, the production is described using the example of a single container, which takes place simultaneously in the molds. In the 1 to 11 Identical components are provided with the same reference symbols.

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 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 opened up 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 a not shown inner area of the suction mold parts 4a, 4b, 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 embodiment shown, 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 hollow-cylindrical 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 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 is arranged pivotably in a receptacle for the shaft 10 which is fastened to the suction mold 4 by means of a shaft 10 oriented transversely to the longitudinal direction of the first holder 8. The first holder 8 can be made of the material shown in the 1 and 2 shown position outside the suction form 4 into the position of the 3 be pivoted 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.

The first holder 8 is in the vertical alignment of the 1 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 which is open at at least one end and in which one or more connecting elements 3 are accommodated. The connecting element 3 is made of an injection-molded and biodegradable thermoplastic in the form of a hardened ring. As shown in the 1 and 2 As can be seen, the tube with the tube opening can be moved over the free end of the second section 8b of the first holder 8 and a connection element 3 can be pushed 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 produced.

After the connecting 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 shown in 3 is shown. 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 holds the connection element 3 in the suction mold opening 7 with the first section 8a in such a way that a gap is formed between the connection element 3 and the suction mold opening 7.

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 rotary shaft 15 via the suction channels 9. The interior of the hollow rotary shaft 15 is connected to the suction device, which generates a negative pressure and sucks out water. This negative pressure is guided through the tubular suction channels 9 made of stainless steel to the wall 5 of the suction mold 4. All 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 rotates.

The pulp 13 is sucked through the hollow cylindrical first section 8a of the holder 8 into the suction mold 4. While the water of the pulp 13 passes through the pores, the fiber material from the pulp 13 is deposited on 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.

When a sufficient amount of pulp has been deposited on the wall 5 of the suction form 4, the suction form 4 is removed from the pulp basin 14, brought into a removal position and opened, as shown in 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 that is 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 that is 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 that the hollow body 1 and the connecting element 3 come to rest in the transfer mold 17. In the 5 In the example shown, the swivel angle is approximately 180°. During swiveling, the hollow body 1 rests against the holder 8 and in particular against its second section 8b. The wet and not very dimensionally stable hollow body 1 can thus be mechanically stabilized so that it deforms only slightly despite its low dimension stability. When the hollow body 1 and the connecting element 3 are in the transfer mold 17, the first holder 8 is arranged partly with the fiber molded body in the transfer mold 17 and partly outside the transfer mold 17. It protrudes through the recess in the transfer mold 17.

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 6 shown. In the 5 to 7 the conveying 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 pulled off 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.

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 by evaporation. While the hollow body 1 is dried in the continuous furnace 19, the rotary shaft 15 with the suction mold 4 and the first holder 8 attached to it is rotated further and fed back to the start of the process in order to produce another fiber molded body.

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

In 7 the hollow body 1 and the connecting element 3 are shown arranged in the opened press mold 20. The transfer of the hollow body 1 and the connecting element 3 from the transfer mold 17 into the press mold 20 can be carried out with 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 press mold 20 receives the hollow body 1.

The mold 20 can have two or more mold parts 20a, 20b. In the closed state, a wall of the mold parts 20a, 20b encloses a second cavity, which is designed essentially complementary to the hollow body 1. Smaller pores are introduced into the wall of the mold 20 than in the suction mold 4, so that the compaction of the hollow body 1 in the mold 20 leads to a smooth surface of the hollow body 1. The pores in the wall of the mold are fluidly connected to one another and to a second suction device (not shown) via second suction channels 22. The mold 20 also has a mold opening in a contact area of the mold parts 20a, 20b, which is designed complementary 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 mold opening so that the opening 2 of the hollow body 1 is aligned with the mold opening.

When the hollow body 1 is arranged in a press mold part 20a as intended, the press mold 20 is closed. Then a second holder 23 with a pressing tool 24 arranged thereon is introduced through the opening 2 in the connection element 3 into the inner volume of the hollow body 1, as shown in 8th shown. The second holder 23 has a fluid line tightly connected to the pressing tool 24. The pressing tool 24 is made of 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 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 from a compressor or a pump can be fed into the pressing tool 24. With a liquid, a higher pressure can be built up within the pressing mold 20 through the pressing 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 compacted, dewatered and solidified. 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 impressed onto the hollow body 1.

The water escaping from the hollow body 1 during compaction is passed through the pores in the wall of the 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 returns to its original position in 8th The pressing tool 24 can then be removed from the opening 2 of the hollow body 1 together with the second holder 23 and the pressing mold 20 is opened.

The hollow body 1 and the connecting element 3 are then removed from the mold 20 by means of the previously mentioned transfer device 21 and placed in a 10 shown coating station. In the coating station, an injector 25 is provided which can be inserted through the opening 2 for filling a coating solution into the inner volume of the hollow body 1. The coating solution can in particular be biodegradable and/or food-compatible. 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 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 by 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 rotationally symmetrical, it can be introduced into a hollow cylinder that can roll along the inclined plane. The entire inner surface of the hollow body 1 is wetted with the coating solution by the rotation. 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 facing 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 in a horizontal alignment of its longitudinal axis and the gripping device can be rotated.

In this orientation, the coated hollow body 1 is transferred by the transfer device 21 to a 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 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 is completed when the hollow body 1 has been completely dried and is transferred from the drying station to a storage facility.

The features of the invention disclosed in the present description, in the drawings and in the claims can be essential for the realization of the invention in its various embodiments both individually and in any combination. 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 competent person skilled in the art.

List of reference symbols

1

Hollow body

2

opening

3

Connection element

4

Suction form

4a, 4b

Suction molded parts

5

Wall of the suction mold

6

cavity

7

first mold opening

8th

first owner

9

first suction channels

10

Wave

11

Feeding device

13

Pulp

14

pool

15

Rotating shaft

17

Transfer form

18

Conveyor system, conveyor belt

19

Continuous furnace

20

Press mold

20a, 20b

Press-molded parts

21

Transfer device

22

second suction channels

23

second holder

24

Press tool

25

Injector

26

Rotation device, inclined plane

27

Radiant heat source, rod-shaped heating device

Claims (13)

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 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 introducing 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 sucking 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 hollow body (1) formed with the connecting element (3) arranged thereon; and - drying the hollow body (1), characterized in that the hollow body (1) is removed from the divided suction mold (4) at the holder (8). Procedure 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 one of the preceding claims, characterized in that the hollow body (1) is transported on the holder (8) into a transfer mold (17) complementary to the hollow body (1) or a split press mold (20). Method according to claim one of the preceding claims, characterized in that the holder (8) is pivoted about a section of the holder (8) protruding from the cavity (6) for removing the hollow body (1) from the divided suction mold (4). Method according to one of the preceding claims, characterized in that the hollow body (1) is compacted in the suction mold (4) and/or the pressing mold (20). Procedure according to Claim 5 , characterized in that the hollow body (1) is compacted 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 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. Procedure 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 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 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 introduced into the split press mold (20); - a compressor; - an injector (25) for a coating solution; - a rotation device (26); - a radiant heat source (27).

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