Method and device for producing a fibrous moulded body

Abstract

The invention relates to a method for producing a fibrous moulded body (1) having the following method steps: arranging a suction mould (2) in a chamber (5), the suction mould having a porous wall (4) the contour of which corresponds to the contour of the fibrous moulded body (1) to be produced, - introducing a fibrous material / air mixture (6) into the chamber (5), wherein the fibrous material is distributed in the air in the form of solid particles, sucking the fibrous material / air mixture (6) through the porous wall (4) of the suction mould (2) and compacting the fibrous material to form the fibrous moulded body (1) on the porous wall (4), removing the fibrous moulded body (1) from the suction mould (2) and from the chamber (5). The invention addresses the problem of providing a technically simple method and a technically simple device that permit quick and energy-efficient production of biodegradable fibrous moulded bodies with particularly low scrap. For this purpose, the fibrous material consists mainly of cellulose fibres, wherein the fibrous material is moist and / or water in the form of droplets or water vapour is admixed to the fibrous material / air mixture.

Description

[0001] METHOD AND DEVICE FOR PRODUCING A FIBER MOLDED BODY

[0002] Description

[0003] The invention relates to a method for producing a fiber molded body and a device for producing a fiber molded body.

[0004] Fiber molded articles are used for a variety of purposes, particularly as transport packaging and to protect sensitive goods. For example, fiber molded articles serve as an alternative to plastic trays, as molded inserts in packaging, and as food packaging.

[0005] It is known to produce fiber molded articles using the fiber casting process. In this process, a suction mold with a porous wall is immersed in a pulp, also known as a fiber slurry. Pulp usually contains at least water and fibers, which are sucked up by the suction mold. The fibers usually consist of wood pulp. Suction is achieved through pores or openings in the porous wall of the suction mold that are smaller than the fibers. Thus, only the water from the pulp is sucked out through the wall of the suction mold, while the fibers are deposited on the wall of the suction mold. The fiber content is increased and compacted on the wall of the suction mold, so that a fiber molded article is created there. After the fiber molded article has been demolded, the dry matter content is further increased by subsequent drying, which solidifies the fiber molded article.

[0006] The fiber casting process can be used to produce fiber molded bodies with complex contours on the suction mold. However, drying the wet fiber molded body is very time- and energy-intensive because the fiber molded body deposited on the wall of the suction mold has a very high water content. The water must be essentially completely evaporated before the formed fiber molded body can be used. Both the water consumption for the fiber casting process and the energy consumption are quite high. Alternatives to the fiber casting process are known in the prior art. For example, document SE 541 995 C2 discloses a process for producing a non-flat fiber molded body referred to as a cellulose product. The process comprises dry forming cellulose fibers into a flat cellulose web in a dry forming unit.For dry forming the cellulose web, the dry forming unit comprises a separation unit for separating cellulose fibers, a forming screen for forming the web from cellulose fibers, and a compaction unit for compacting the cellulose fibers. Water and one or more additives are added to the cellulose fibers and / or the cellulose blank. The cellulose product is formed by heating the cellulose web to a forming temperature in the range of 140°C to 200°C and pressing the cellulose blank with a forming pressure of at least 4 MPa. The additive(s) are sprinkled in solid form onto the cellulose fibers and / or the cellulose web. In this process, the non-flat fiber molded body is produced via a flat cellulose web.

[0007] A process for producing a fiber molded article, referred to as a molded product, is also known from EP 3 889 347 A1. The process comprises mixing fibers with a composite material to form a mixture, wherein the composite material contains cellulose fibers and 30% to 50% starch at least partially fused with the cellulose fibers. The mixture is moistened at least once, and the moistened mixture is formed into the molded product by pressurization and heating. In particular, the moistened mixture is deposited on a mesh conveyor belt and enriched there. The conveyor belt feeds the fiber web into a molding device, in which the fiber web is pressed. In this process, too, the fiber molded article is produced via a flat fiber web.

[0008] Producing a fiber web, which is then molded into the desired fiber molded article, is time- and energy-intensive. Furthermore, the fiber web can thin and / or tear during the molding process because the molding process involves significant deformation of the fiber web.

[0009] US Pat. No. 5,376,327 A and DE 10 2015200275 A1 describe processes for producing molded fiber bodies with carbon fibers and plastic fibers. The invention is based on the object of providing a technically simple process and a technically simple device that enable the rapid and energy-efficient production of biodegradable molded fiber bodies with particularly low waste.

[0010] According to the invention, this object is achieved by a method having the features of claim 1 and by a device having the features of claim 10. Advantageous embodiments emerge from the dependent claims.

[0011] The process described here for producing a fiber molded body comprises the following process steps:

[0012] - Arranging a suction mold with a porous wall, the contour of which corresponds to the contour of the fiber molded body to be produced, in a chamber,

[0013] - Introducing a fibre material-air mixture into the chamber, whereby the fibre material is distributed in the air in the form of solid particles,

[0014] - Suction of the fiber material-air mixture through the porous wall of the suction mold and compaction of the fiber material to the fiber molded body on the porous wall,

[0015] - Removing the fibre moulded body from the suction mould and from the chamber,

[0016] - wherein the fiber material consists mainly of cellulose fibers and wherein the fiber material is moist and / or water in the form of droplets or water vapor is added to the fiber material-air mixture.

[0017] The invention is therefore based on the idea of ​​depositing the starting materials from which the fiber molded body is formed (in particular fiber material) directly from the air onto a porous wall of a suction mold and compacting them there, so that the fiber molded body has the geometry (contour) to be produced or at least substantially the geometry (contour) to be produced immediately after the depositing and compacting of the starting materials.

[0018] The molded fiber body is made from biodegradable and preferably compostable starting materials. The fiber material is then - depending on the requirements for the optical properties of the molded fiber body - formed primarily from cellulose, other recycled fibers and / or fresh fibers, each of which is biodegradable and preferably compostable. This makes the molded fiber body itself biodegradable and preferably compostable. The fibers can consist primarily of cellulose fibers, as known from the conventional production of molded fiber bodies using the pulp molding process. However, other fibers, e.g. hemp fibers, can also be used. This allows the production of molded fiber bodies with high strength and good mechanical properties. Depending on the intended use, the fibers can also be mixed from different starting materials.

[0019] The fiber material can be introduced into the fiber-air mixture in a slightly moistened state so that the fiber material sets during compaction to form the molded body. The moisture content of the fiber material can cause problems during the swirling of the fibers in the air. For this reason, water in the form of droplets or steam can be added to the swirled fiber-air mixture in order to achieve the optimal moisture content for the fibers to set during compaction. It is also possible to swirl completely dry fibers with air and add the full amount of water required for setting to the swirled fiber-air mixture.

[0020] In some embodiments, a first fiber material-air mixture can be introduced into the chamber and sucked in, so that a first layer of fiber material is formed on the porous wall of the suction mold, and then at least one further fiber material-air mixture can be introduced into the chamber and sucked in, so that at least one further layer of fiber material is formed on the porous wall of the suction mold. The layers of fiber material can be compressed to form the fiber molded body on the porous wall, and the fiber molded body can be removed from the suction mold. In other words, a first mixture can be fed into the chamber, forming a first layer on the porous wall, and then a second layer can be fed in, forming a second layer on the first layer. This process can be repeated with a third and fourth layer if necessary.The fiber-air mixture used to form the various layers can be different. For example, the first fiber-air mixture can contain a different pigment than the second. In this case, the outer layer of the resulting molded article will have a different color than the inner layer. Different additives can also be added to the layers. For example, if the fiber molded article is intended to be used to package food, the inner layer can be composed in such a way that its direct contact with the food is safe. A second layer can be deposited on top of this inner layer. This second layer imparts a certain degree of impermeability or strength to the fiber molded article, but is not suitable for direct contact with food.Multilayer molded articles can also be formed, with each layer having a distinct function, such as high oxygen impermeability, high moisture resistance, or high light resistance. These different properties in the different layers can be achieved by changing the composition of the fiber-air mixture to create a layer with a specific desired property.

[0021] The suction mold can, for example, be a hollow body having the porous wall and a suction opening through which fluid can flow and which is connected to the pores of the wall for connecting a suction device. Alternatively, the suction mold can be designed as a body formed from a porous structure with a suction opening for connecting a suction device. In this case, a surface or at least a surface section of the body forms the porous wall of the suction mold. The contour of the porous wall corresponds to the contour of the fiber molded body to be produced. In other words, the surface geometry of the porous wall or a section of the porous wall and a surface geometry of the fiber molded body to be produced are complementary or substantially complementary to one another.Using the suction device connected to the suction mold, either a negative or positive pressure can be generated in the suction mold, and air can be sucked in or blown out through the pores of the porous wall of the suction mold. The pores in the porous wall are preferably designed so that the fiber material is deposited on the wall when the fiber material-air mixture is sucked in.

[0022] The porous wall of the suction mold can be formed, for example, by a metal wire mesh. However, it can also be produced as a solid wall with air channels, for example, using an additive manufacturing process (3D printing). In the latter case, the suction mold is more stable.

[0023] The chamber is a predefined space in which the fiber molded body is formed on the porous wall of the suction mold. The space can have a wall with one or more openings, through which the starting materials from which the fiber molded body is formed and / or the suction mold can be introduced into the space. The opening in the wall can be at least partially closable, for example, by means of a door, a flap, or a slide. The wall and the at least partially closable opening effectively prevent the fiber material-air mixture from escaping into the air outside the chamber.

[0024] The suction mold can be positioned in the chamber manually or automatically. Automatic positioning allows the process described here to be automated. Automatic positioning can be achieved, for example, by a suction mold carrier that is moved by an actuator that can be driven electrically or pneumatically, for example. The actuator drive can be functionally connected to a control unit. The suction mold carrier can be designed, for example, as a conveyor belt on which the suction mold is positioned and with which the suction mold is moved from a support position into the chamber. Alternatively, the suction mold carrier can be a robot arm, for example.

[0025] In the process described here, a plurality of suction molds with identical or differently shaped porous walls can be arranged simultaneously in the chamber, so that a plurality of fiber molded bodies with identical or differently shaped contours can be formed simultaneously. For small fiber molded bodies, each fiber molded body can also correspond to one of several sections of the porous wall of the suction mold. The simultaneous production of several fiber molded bodies allows for particularly rapid and energy-efficient production.

[0026] Before, during, or after the suction mold is placed in the chamber, the fiber material-air mixture is introduced into the chamber. For this purpose, the fiber material-air mixture can be premixed outside the chamber so that the fiber material is already dispersed in the air in the form of solid particles upon introduction. In this case, the fiber material-air mixture can, for example, be blown into the chamber. Alternatively, the fiber material can be introduced into the chamber separately from the air. The fiber material can, for example, be continuously sprinkled into the already air-filled chamber during the forming process, or poured all at once as a loose material into the already air-filled chamber.

[0027] With the process described here, the desired fiber molded body is formed directly in a single molding step, without first producing an intermediate product that requires further processing. This saves considerable time. Furthermore, the resulting fiber molded body contains hardly any water and therefore does not require drying. Water is added—if at all—only to the extent necessary for optimal bonding of the components of the fiber molded body's wall.

[0028] Regardless of the method of introducing the fiber material, it can be advantageous to actively and specifically move the air, the fiber material, and / or the fiber material-air mixture in the chamber in order to achieve homogeneous mixing of the air with the starting materials from which the fiber molded body is formed. The active and targeted movement of the air, the fiber material, and / or the fiber material-air mixture is achieved by means of a device for mixing the fiber material with air, for example a propeller. The propeller swirls the air and / or the fiber material-air mixture so that the fiber material is homogeneously distributed in the air. The propeller can, in particular, generate an upward flow. This can create a fluidized bed in the chamber. A fluidized bed is a bed of solid particles that is swirled up and fluidized by an upward flow of a fluid.The term "fluidized" means that the (former) bed has fluid-like properties. Alternatively or in addition to the propeller, the device for mixing the fiber material with air can, for example, comprise a vibrating membrane, whereby the vibrating membrane swirls up the air in front of it, the fiber material-air mixture, and / or particles of the starting materials deposited on the vibrating membrane through vibration.

[0029] To form the fiber molded body, air is drawn through the porous wall of the suction mold. The fiber material is deposited on the porous wall. After a certain suction time, the fiber material is compressed against the porous wall by the suction of the fiber material-air mixture, and a fiber molded body with the desired contour and wall thickness is formed.

[0030] When a predetermined suction time and / or a desired wall thickness of the fiber molded body is reached, the fiber molded body is removed from the suction mold and from the chamber and further processed or placed in an intermediate storage area.

[0031] In practice, the porous wall of the suction mold can have a three-dimensional contour with multiple wall sections. The wall sections of the suction mold define different sections of the molded body to be produced. The individual wall sections can be flat, convex, and / or concave. This allows three-dimensional fiber molded bodies with multiple surface sections to be formed on the porous wall, for example, a cup-shaped fiber molded body with a flat bottom and a cylindrical cup wall. As mentioned above, multiple fiber molded bodies can also be formed on multiple surface sections of a suction mold.

[0032] Furthermore, in practice, the fiber material can be mixed with the air in the form of fiber dust or short fibers to form the fiber material-air mixture, and / or the fiber material-air mixture can be an aerosol, wherein the fiber material is dispersed in the air as suspended particles. Fiber dust refers to fiber material whose fibers are smaller than 500 pm and preferably smaller than 200 pm. If the fibers of the fiber material are even smaller than 20 pm and more preferably smaller than 10 pm, the fiber material-air mixture can be an aerosol. An aerosol is a mixture of solid and / or liquid suspended particles in a gas. The fiber material then floats in the air, sinks only very slowly, and in particular does not precipitate within a few seconds.In an aerosol, the fiber material is uniformly distributed throughout the air, allowing it to be deposited particularly evenly on the porous wall of the suction mold using the process described here. Distributing the fiber material in the air requires, at most, occasional active and targeted movement of the fiber material-air mixture in an aerosol. This makes forming the fiber molded body technically simple and particularly energy-efficient. Furthermore, the very small particles of the fiber material in an aerosol allow for the resulting fiber molded body to exhibit outstanding properties. For example, the fiber molded body can exhibit particularly high strength, high density, and / or high resistance to moisture or aggressive substances. However, it is also possible to process significantly longer fibers.This may require more intense intermingling to ensure the fibers are evenly deposited on the porous surface of the absorbent mold. A longer fiber length may be desirable, particularly when processing hemp fibers.

[0033] In practice, at least one of the following additives can be added to the fiber material-air mixture:

[0034] - sugar and / or starch,

[0035] - wax,

[0036] - lipids,

[0037] - Minerals. The additives can also be starting materials from which the fiber molded body is formed. If at least one of the additives is provided, the air and the starting materials—that is, the fiber material and the at least one additive—are sucked into the suction mold, and the starting materials are deposited together on the porous wall of the suction mold. This creates a fiber molded body with evenly distributed starting materials. The additives can further improve the properties of the fiber molded body, in particular, the strength, impermeability, and / or moisture resistance can be further increased.

[0038] The water can be added in the form of droplets or as steam if the swirled fiber material is not sufficiently moist itself. The water can deposit on the surface of the fiber material and / or penetrate the fiber material. The adhesion of the water can increase the adhesion of the fibers deposited on the porous wall to one another. In addition, the water can dissolve the fiber material and thus further increase the adhesion of the fibers. Overall, this can form a stable fiber composite, which enables easy and safe removal of the molded fiber body from the suction mold. The strength of the finished molded fiber body can also be increased. However, the water content of this molded fiber body is considerably lower than when produced from fiber pulp.

[0039] The starting materials can also contain sugar, in particular glucose, sucrose, fructose, maltose, lactose, raffinose, stachyose, as well as starch or a mixture of at least two of the aforementioned components. Furthermore, the sugar or starch can be added, in particular in the form of solid particles. The sugar or starch can also be used to increase the adhesion of the fibers deposited on the porous wall to one another, in particular if the sugar or starch is first heated, melted and / or dissolved by moisture, and later cooled or dried again in the molded fiber body. The sugar or starch then acts as a natural adhesive that bonds the fibers of the molded fiber body together.The starch can also increase the hardness and abrasion resistance of the molded fiber body because the hardness of sugar crystals is usually greater than the hardness of most fiber materials and in particular greater than the hardness of cellulose fibers.

[0040] The wax can be added in the form of solid particles or drops.

[0041] In particular, carnauba wax and / or beeswax can be added. Carnauba wax is a very hard, tropical wax with a high melting point (approx. 85-89°C). It has hardly any odor or taste of its own and is waterproof. It is very brittle when dry and hardens within seconds. Due to its hardness, it is also very resistant to abrasion. It is approved for food packaging and has long been used as a coating to increase the shelf life of, for example, mangoes, sweets, etc. The wax can also contain beeswax or other natural waxes. Combinations of biodegradable and, if possible, compostable waxes can be used, which give the molded fiber body high strength and are particularly suitable for use with packaged food. In addition to carnauba wax and beeswax, shellac and sugar cane wax are also suitable. Beeswax is aA wax produced in Europe that is less hard than carnauba wax. When mixed with carnauba wax, beeswax helps reduce brittleness. It also has hardly any odor or taste of its own and is approved for use in contact with food. Its melting point is approximately 65°C.

[0042] The lipids can also be added in the form of solid particles or droplets. Lipids are hydrophobic. When included in the fiber molding, they can reduce the wettability of the fiber molding and / or increase the fiber molding's moisture resistance.

[0043] It should be noted that this list of additives is not exhaustive. Other additives, such as minerals or proteins, as well as dyes, can be added to the fluidized fiber-air mixture. The additives to be added are selected depending on the product to be manufactured and, in particular, the desired product properties.

[0044] The size of the additives added as solid particles or droplets is selected such that the additives are homogeneously distributed in the chamber together with the fiber material and thus the fiber material-air mixture contains the additives evenly distributed. Since the additives are intended to be separated and compacted together with the fiber material, the additives added as solid particles or droplets are preferably larger than the pores in the porous wall of the suction mold. If the fiber material is mixed with the air as fiber dust, the particle size of the additives can preferably correspond to the particle size of the fiber material. If the fiber material-air mixture is an aerosol, the particle size of the additives can in particular be selected to be so small that the additives float with the fibers in the chamber and thus the fiber material-air mixture containing the additives is an aerosol overall.The particle size of the additives can then be, in particular, less than 20 pm and preferably less than 10 pm. The water can, in particular, be in vapor form.

[0045] In practice, the additives can be stored in separate storage containers. The additives can be mixed with the fiber material before the starting materials are introduced into the chamber. Alternatively, the fiber material and the additives stored in separate storage containers can be introduced separately into the chamber, which allows for particularly high flexibility. For example, the fiber material can be introduced as described above, and the additives can be mixed with air in the separate storage containers to form separate additive-air mixtures, fluidized, and then fed into the chamber as separate flows through pipes. By swirling these flows in the chamber, the additives are homogeneously mixed with the fibers and the air in the chamber to form the fiber material-air mixture.

[0046] The fiber molded body can be removed from the suction mold using a transfer mold. For this purpose, the transfer mold can have a wall that is essentially complementary to the porous wall of the suction mold and can be pressed with a certain pressure against the fiber molded body formed on the porous wall of the suction mold. This allows the fiber molded body to be compacted. In particular, if the porous wall of the suction mold is formed with a large wall thickness using additive manufacturing, a high strength of the resulting fiber molded body can be achieved simply by pressing the suction mold and transfer mold together.

[0047] In practice, the fiber molded body can be transferred to a compression mold after removal from the suction mold, and a counter mold can be pressed against the fiber molded body arranged in the compression mold. The compression mold has a wall whose contour essentially corresponds to the contour of the porous wall of the suction mold. Preferably, the wall of the compression mold has no pores or smaller and / or fewer pores than the porous wall of the suction mold. The wall of the compression mold is preferably smooth. The counter mold has a wall that is essentially complementary to the wall of the compression mold and is also preferably smooth. The counter mold can also have pores.

[0048] By pressing the counter-mold against the fiber molded body arranged in the press mold, the fiber molded body can be clamped over its entire surface between the wall of the press mold and the wall of the counter-mold, and the fiber molded body is pressed and further compacted by the mechanical pressure. Due to the essentially complementary walls of the press mold and the counter-mold, the contour of the fiber molded body can be slightly modified. In particular, small steps and / or undercuts can be introduced. Furthermore, pressing the counter-mold against the fiber molded body can create a uniform wall thickness for the fiber molded body. The surfaces of the fiber molded body can be made particularly smooth through pressing, thus giving the fiber molded body a high-quality appearance. If the fiber molded body contains residual water, the water can be pressed out of the fiber molded body.Unlike a fiber molded body made from pulp, a fiber molded body made according to the invention has only a very low water content and only needs to be dried slightly - if at all.

[0049] Once the pressing of the mold and counter-mold is complete, the mold and counter-mold can be separated. The counter-mold is then no longer engaged with the mold. The fiber molded body can be removed and further processed.

[0050] In practice, it is also possible to press the fiber molded body in multiple steps. For this purpose, after pressing in the suction mold and the transfer mold, the fiber molded body can be pressed in a first mold with a first counter mold. If necessary, the fiber molded body can be transferred to a second mold and pressed with a second counter mold. Further pressing steps can be carried out in a similar manner. By repeatedly pressing in different molds, the density can be successively increased and / or the surface quality of the fiber molded body can be successively improved.

[0051] In practice, as already mentioned, the removal and / or transfer of the fiber molded body from the suction mold to the compression mold can be carried out using a transfer mold. The transfer mold has a wall that is essentially complementary to the porous wall of the suction mold. The transfer mold can be arranged on a transfer mold carrier that can be driven by an actuator and functionally connected to a control unit. It can be brought into engagement with the suction mold such that the wall of the transfer mold rests against the fiber molded body and removes it from the suction mold. The transfer mold then transfers the fiber molded body to an intermediate storage area or into the compression mold. The transfer mold can also be used to transfer the fiber molded body from a first compression mold to another compression mold.In practice, the transfer mold can be the counter mold described above, which serves to press the fiber molded body against the porous wall of the suction mold and / or the compression mold.

[0052] The wall of the transfer mold can have pores, with the pores being connected to a suction device for flowing through them to create a negative or positive pressure at the pores. The negative pressure draws the fiber molded body in during removal from the suction mold, transfer to the compression mold, and removal from the compression mold. The positive pressure facilitates easy detachment of the fiber molded body from the transfer mold. At the same time, air can be blown through the porous wall of the suction mold to assist in the release of the fiber molded body.

[0053] In practice, the suction mold, the compression mold, and / or the counter mold can be heated. Heating the suction mold can serve to heat the starting materials to a predetermined temperature at which the starting materials are particularly easy to process and the fibers adhere particularly well to one another. In particular, the suction mold, the compression mold, and / or the counter mold can be heated to a temperature of 130°C to 300°C, and preferably from 180°C to 240°C. These temperature ranges are above the melting point of most waxes (especially carnauba wax and beeswax) and many sugars (especially glucose, sucrose, fructose, maltose, lactose, raffinose, stachyose) or starch, so that the wax and / or the sugar / starch in the fiber molded body can be liquid at the suction mold, the compression mold, and / or the counter mold.If the fiber molded body contains water, the water further evaporates from the fiber molded body at the temperatures of the above temperature windows and the fiber molded body is dried.

[0054] In practice, the fiber molded body can also be coated with a coating solution. The coating solution can contain at least one of the following components:

[0055] - cellulose fibers;

[0056] - Casein; - Whey;

[0057] - Agar-agar;

[0058] - Psyllium husks.

[0059] If the fiber molded body contains moisture, coating can take place, in particular, after the moisture has been removed from the fiber molded body. Coating the fiber molded body can be carried out, in particular, by spraying a coating solution onto the fiber molded body in the suction mold, the compression mold, the counter mold, and / or in a coating station. Additionally or alternatively, the fiber molded body can also be immersed in a coating solution in a coating station or poured with a coating solution for coating. The coating can also be applied as a partial coating to only part of the surfaces of the fiber molded body.

[0060] A coating can impart advantageous properties to the fiber molded article. For example, a layer of color or a water-repellent functional layer can be applied. The coating can also increase the impermeability of the fiber molded article and its resistance to moisture or aggressive substances. Finally, the coating can increase its strength. This allows fiber molded articles to be molded into hard objects such as knives or forks.

[0061] The invention also relates to a device for producing a fiber molded body. The device comprises at least the following components:

[0062] - a chamber,

[0063] - at least one device for mixing fiber material with air to produce a fiber material-air mixture in the chamber,

[0064] - at least one suction mold which can be introduced into the chamber and has a porous wall for depositing and compacting fiber material from the fiber material-air mixture, wherein the contour of the porous wall corresponds to the contour of the fiber molded body to be produced and

[0065] - at least one extraction device.

[0066] The at least one suction device is connected to the suction mold in a flow-through manner, so that either a negative pressure or a positive pressure can be generated at the porous wall. The device can also have more than one suction mold. In this case, each of the suction molds is connected to the suction device in a flow-through manner or to a separate suction device. The porous wall of the suction mold can in particular have a three-dimensional contour with several wall sections, wherein the wall sections can be flat, convex and / or concave. The suction mold can also have several wall regions, each of which forms a fiber molded body. The method described above can be carried out using the device. The description of the device therefore also includes the features described above in connection with the method and their advantages.

[0067] In practice, the device for mixing the fiber material with air to form the fiber material-air mixture may comprise a propeller and / or a vibrating membrane. The movement of the propeller or vibrating membrane allows the starting materials to be effectively and homogeneously mixed with the air in the chamber to form the fiber material-air mixture, as described above.

[0068] In practice, the device may further comprise at least one of the following elements, the above description explaining details of these elements and associated effects in more detail:

[0069] - at least one suction mold carrier that can be driven by an actuator;

[0070] - separate storage containers for the fiber material, water, sugar, starch, wax and / or lipids;

[0071] - at least one device for heating the fibre material, water, sugar, starch and / or wax;

[0072] - at least one device for mixing water, sugar, starch and / or wax with air;

[0073] - at least one transfer form;

[0074] - at least one transfer mold carrier which can be driven via an actuator;

[0075] - at least one mold and at least one counter-mold for pressing the fiber molded body;

[0076] - at least one device for heating the suction mold, the compression mold and / or the counter mold;

[0077] - at least one coating station for coating the fiber molded body;

[0078] - at least one control unit.

[0079] All elements of the device can be functionally connected to the at least one control unit, so that the device can carry out the method automatically. Further practical embodiments and advantages of the invention are described below in conjunction with the drawings. They show:

[0080] Fig. 1 is a schematic representation of an apparatus according to the invention for producing a plurality of fiber molded bodies;

[0081] Fig. 2 shows a first partial view of the device from Fig. 1 and the introduction of starting materials into the chamber;

[0082] Fig. 3 shows the partial representation from Figure 2 and the suction of the starting materials onto the suction molds;

[0083] Fig. 4 shows the partial representation from Figure 2 with the formed fiber molded bodies;

[0084] Fig. 5 shows the partial view from Figure 2 with a transfer device above the fiber molded bodies;

[0085] Fig. 6 the partial representation from Figure 2 and the removal of the fiber molded bodies from the suction mold;

[0086] Fig. 7 shows the partial representation from Figure 2 and the transfer of the fiber molded bodies in the transfer mold at a first point in time;

[0087] Fig. 8 shows a second partial view of the device from Fig. 1 and the transfer of the fiber molded bodies in the transfer mold at a second time;

[0088] Fig. 9 shows a third partial view of the device and the pressing of the fiber molded bodies in molds;

[0089] Fig. 10 shows the partial view from Figure 9 and the transfer of the pressed fiber molded bodies to a conveyor belt;

[0090] Fig. 11 shows the partial view from Figure 9 and the fiber moldings placed on the conveyor belt. Figures 1 to 11 show the sequence of the method described here and a device for carrying out the method. The figures show a device with which four fiber moldings can be produced simultaneously. It should be noted that a method and device according to the invention are not limited to the simultaneous production of four fiber moldings. Rather, the number of fiber moldings produced simultaneously can be adapted to the requirements. The production is described below using the example of one of the four fiber moldings shown, with a suction mold being provided for each fiber molding. It should be noted that a suction mold with several surface regions can also be used, with one fiber molding being produced in each surface region.In the figures, identical components are provided with identical reference symbols.

[0091] To produce a fiber molded body 1, a suction mold 2 is first provided. The suction mold 2 is designed as a hollow body with a plurality of walls surrounding a cavity, one of the walls being porous. The suction mold 2 is arranged on a suction mold carrier 3 carrying a plurality of suction molds such that the porous wall 4 of the suction mold 2 points upwards. The contour of the porous wall 4 corresponds to the contour of the fiber molded body 1 to be produced. It is three-dimensional and comprises several wall sections, one part of which is flat and another part of which is convex. In the example described here, the fiber molded body 1 and the porous wall 4 as a whole have the contour of an egg tray or egg carton. The porous wall 4 of the suction mold 2 can either consist of a wire mesh or be formed using an additive manufacturing process.

[0092] On the side opposite the porous wall 4, the suction mold 2 has a suction opening (not shown) through which the pores of the porous wall 4 are fluidly connected to a suction device (not shown). The fluid connection is achieved in this case by the suction mold carrier 3 being hollow, and air can flow into the suction mold carrier 3 through openings (not shown) located below the suction mold 2 and to the suction device. The suction device is, for example, a pump.

[0093] By means of the suction mold carrier 3, the suction mold 2 is introduced into an air-filled chamber 5 for forming the fiber molded body 1. The suction mold 2 introduced into the chamber 5 is shown, for example, in Figure 2. For the purpose of introduction, the chamber 5 has a first opening at the bottom through which the suction mold 2 is introduced and which is completely closed by the suction mold carrier 3 when the suction mold 2 is introduced into the chamber. Alternatively, the suction mold carrier 3 can be arranged substantially completely within the chamber 5, and the opening can be closed by means of a separate device.

[0094] As also shown in Figure 2, after the suction mold 2 has been introduced into the air-filled chamber 5, a fiber material-air mixture 6 is introduced into the chamber 5. The fiber material-air mixture 6 comprises at least the components air and fiber material. If the fiber material does not have sufficient moisture, additional water can be added in the form of fine droplets or steam. The fiber material-air mixture 6 can further comprise the additives sugar, starch, and wax, wherein the sugar is preferably lactose and the wax can be a mixture of carnauba wax and beeswax. The fiber material, the water, the sugar / starch, and the wax are the starting materials from which the fiber molded body 1 is formed. The fiber material is stored in a first storage container 7. It is sprinkled into the chamber 5 in the form of solid particles through a first pipe 8 and a second opening in the ceiling of the chamber 5.When the fiber material is sprinkled in, it mixes with the air already present in chamber 5 to form the fiber material-air mixture 6. The particle size of the fibers can be 10 pm or smaller, so that the fiber material floats in the air in chamber 5 in the form of suspended particles, and the fiber material-air mixture 6 is an aerosol. Alternatively, it is also possible to use significantly longer fibers, for example, with a length of approximately 200 pm, which sink to the suction mold after being sprinkled in.

[0095] The water is stored in a second storage container 9. It is heated by means of a first heating device (not shown here) until it evaporates and then flows in the form of steam through a second pipe 10 and through the second opening into the chamber 5. As an alternative to introducing the water in the form of steam into the chamber 5, the water can also be sprayed into the chamber 5 in the form of droplets. For this purpose, a pump (not shown here) can pump the water from the second storage container 9 through the second pipe 10 to the second opening, where the water can be sprayed into the chamber 5, for example using a nozzle. The second pipe 10 forms the supply device for the water. The first heating device is then not required, but can optionally be used to spray heated water droplets into the chamber 5.The sugar is stored in a third storage container 11 and sprinkled into the chamber 5 in the form of solid particles through a third pipe 12 and the second opening. The wax is stored in a fourth storage container 13 and sprinkled into the chamber 5 in the form of solid particles through a fourth pipe 14 and the second opening. The introduction of the different starting materials into the chamber 5 can take place simultaneously or sequentially. If the fiber material is introduced in the form of suspended particles, the sugar and wax particles can also be so small that they float in the fiber material-air mixture 6, at least briefly. As a result, the air, the fiber material, the water vapor, the sugar particles, and the wax particles mix in the chamber 5 to form the fiber material-air mixture 6 without any targeted and active support. During mixing, the steam moistens the fiber material and the sugar.This causes the starch in the fibers and the sugar to dissolve.

[0096] It is also possible to swirl the air or the fiber material-air mixture 6 in the chamber 5 using a device (not shown here) for mixing the fiber material with air in the form of a propeller or a vibrating membrane. This allows the starting materials to be distributed even more effectively and evenly in the air. The device for mixing the fiber material can, in particular, create a flow of the fiber material-air mixture 6 directed from the floor of the chamber 5 toward the ceiling of the chamber 5, thus creating a fluidized bed in the chamber 5. This also enables the processing of significantly larger particles, which would sink in the air without the fluidizing agents.

[0097] Figure 3 shows the suction of the fiber material-air mixture 6 through the porous wall 4 of the suction mold 2 and the compaction of the fiber material and the additives to form the fiber molded body 1 on the wall 4. To do this, first close the second opening in the ceiling of the chamber 5. Subsequently, the air in the fiber material-air mixture 6 is sucked out through the pores in the porous wall 4, as described above. The moistened fiber material, the moistened sugar, and the wax are deposited on the porous wall 4 because the pores are smaller than the fibers, the sugar particles, and the wax particles. The fiber material, the sugar, and the wax are deposited on the porous wall 4 and compacted. During the deposition of these particles, the porous wall 4 of the suction mold 2 is heated by means of a second heating device to a temperature in the range of 180°C to 240°C, for example 200°C.As a result, the water from the moistened starting materials evaporates very quickly, and the molded fiber body dries. Part of the evaporated water is sucked away by the suction mold 2 and partly returned to the fiber material-air mixture 6. At the same time, the sugar particles and wax particles deposited on the suction mold 2 melt, so that these additives are coated in liquid form around the fibers. The molded fiber body 1 shown in Figure 3 is not yet finished. After a certain suction time, the fully deposited molded fiber body 1 shown in Figure 4, with evenly distributed starting materials and a desired wall thickness, is formed in the manner described here.

[0098] Optionally, the suction process can be carried out during a first suction time with a first fiber material-air mixture 6 and during a subsequent second suction time with a first fiber material-air mixture 6. The second mixture can have a different composition than the first mixture. In this way, two layers with different properties, such as color, impermeability, water resistance, etc., form on the suction form 2.

[0099] After the fiber molded body 1 has been formed on the porous wall 4, it is removed from the suction mold 2. Figures 4 to 7 show that for this purpose a third opening is first opened in a side wall of the chamber 5 (Figure 4). A transfer mold 15, which is arranged on a transfer mold carrier 16, is introduced into the chamber 5 through the third opening and placed above the suction mold 2 and the fiber molded body 1 (Figure 5). The transfer mold carrier 16 is lowered and the transfer mold 15 is brought into engagement with the suction mold 2 such that a porous wall (not shown) of the transfer mold 15 lies flat against the fiber molded body 1 (Figure 6). The fiber molded body 1 thus lies between the porous wall 4 of the suction mold 2 and the porous wall of the transfer mold 15. The transfer mold 15 can be pressed against the suction mold 2 with an axial pressure, so that the fiber molded body 1 located therebetween is already compacted before removal.This applies in particular if the porous wall of the suction mold 2 is stable, e.g. if it was manufactured from plastic or metal by additive manufacturing.

[0100] For removal, the fiber molded body 1 is sucked through the pores in the porous wall of the transfer mold 15, while air is blown through the pores in the porous wall 4 of the suction mold 2. The fiber molded body 1 can thus be easily lifted from the transfer mold 15. The fiber molded body 1 is then removed from the chamber 5 through the third opening using the transfer mold 15 (Figure 7). The third opening is then closed again, allowing the above-described process for forming a fiber molded body to take place again on the suction mold 2 arranged in the chamber 5.

[0101] The fiber molded body 1 removed from the chamber 5 and held by the transfer mold 15 is transferred to a press mold 17, as shown in Figures 8 and 9. The fiber molded body 1 is pressed in the press mold 17. For pressing, the transfer mold 15 with the fiber molded body 1 arranged thereon is pressed against a porous wall (not shown) of the press mold 17, which is essentially complementary to the porous wall of the transfer mold 15. The transfer mold 15 is therefore functionally also a counter mold for the press mold 17 during pressing. The porous walls of the transfer mold 15 and the press mold 17 contain significantly fewer pores overall than the porous wall 4 of the suction mold 2. As a result, the surface of the porous walls of the transfer mold 15 and the press mold 17 is smoother than the surface of the porous wall 4 of the suction mold.Pressing compacts the fiber molded body 1, forcing out moisture and pressing the fibers tightly together, increasing the strength and density of the fiber molded body 1. Furthermore, the desired final geometry is imprinted on the fiber molded body 1, e.g., by increasing the sharpness of any existing edges, and the surface of the fiber molded body 1 is smoothed.

[0102] After pressing the fiber molded body 1, it is transferred to a conveyor belt 18 using the transfer mold 15, as shown in Figure 10. When the transfer mold 17 is positioned above the conveyor belt 18, the suction of the fiber molded body 1 is stopped, and air is blown out through the porous wall of the transfer mold 17, so that the fiber molded body 1 is deposited on the conveyor belt 18, as shown in Figure 11. The conveyor belt 18 conveys the fiber molded body 1 to a coating station (not shown here), in which the fiber molded body 1 is sprayed with a coating solution containing cellulose fibers, casein, whey, agar agar, and / or psyllium husks. Alternatively, the conveyor belt 18 can transport the fiber molded body 1 to an intermediate storage facility.

[0103] The elements of the device described above are functionally connected to a control unit that monitors and controls the parameters of the process. In particular, the control unit controls

[0104] - the opening and closing of the first, second and third openings, - the suction form carrier,

[0105] - the supply of raw materials into the chamber (e.g. time and quantity),

[0106] - the devices for heating the water and the suction form,

[0107] - the device for mixing the fiber material with air (e.g. time and intensity),

[0108] - the suction of fiber material-air mixture through the suction form (e.g. time and intensity),

[0109] - the transfer mold carrier (e.g. the movement and suction of the fiber molded body),

[0110] - the pressure in the mold, and

[0111] - the movement of the conveyor belt.

[0112] By controlling these elements of the device, the process can be automated.

[0113] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0114] List of reference symbols

[0115] 1 fiber molded body

[0116] 2 suction form

[0117] 3 suction cup carriers

[0118] 4 porous wall of the suction mold

[0119] 5 chamber

[0120] 6 Fiber material-air mixture

[0121] 7 first storage container

[0122] 8 first pipeline

[0123] 9 second storage container

[0124] 10 second pipeline, supply device

[0125] 11 third storage container

[0126] 12 third pipeline

[0127] 13 fourth storage container

[0128] 14 fourth pipeline

[0129] 15 Transfer mold, counter mold

[0130] 16 transfer mold carriers

[0131] 17 Press mold

[0132] 18 Conveyor belt

Claims

Patent claims 1. A process for producing a fiber molded body (1), comprising the following process steps: - arranging a suction mold (2) with a porous wall (4), the contour of which corresponds to the contour of the fiber molded body (1) to be produced, in a chamber (5), - introducing a fibre material-air mixture (6) into the chamber (5), wherein the fibre material is distributed in the air in the form of solid particles, - Suction of the fiber material-air mixture (6) through the porous wall (4) of the suction mold (2) and compacting the fiber material to the fiber molded body (1) on the porous wall (4), - Removing the fiber molded body (1) from the suction mold (2) and from the chamber (5), characterized in that the fiber material consists mainly of cellulose fibers, wherein the fiber material is moist and / or water in the form of droplets or water vapor is added to the fiber material-air mixture.

2. Method according to claim 1, characterized in that - a first fiber material-air mixture (6) is introduced into the chamber (5) and sucked in, so that a first layer of fiber material is formed on the porous wall (4) of the suction mold (2); - at least one further fibre material-air mixture (6) is introduced into the chamber (5) and sucked in, so that at least one further layer of fibre material is formed on the porous wall (4) of the suction form (2); - the layers of fiber material are compressed to form the fiber molded body (1) on the porous wall (4) and the fiber molded body (1) is removed from the suction mold.

3. Method according to one of claims 1 or 2, characterized in that the porous wall (4) of the suction mold (2) has a three-dimensional contour with several wall sections.

4. Method according to one of claims 1 to 3, characterized in that the fiber material in the form of fiber dust is mixed with the air to form the fiber material-air mixture (6) and / or the fiber material-air mixture (6) is an aerosol, the fiber material being distributed in the air as solid suspended particles. Method according to one of claims 1 to 4, characterized in that at least one of the following additives is additionally added to the fiber material-air mixture (6): - sugar and / or starch, - wax, - lipids, - Minerals. Method according to claim 5, characterized in that the additives are stored in separate storage containers (9, 11, 13). Method according to one of the preceding claims, characterized in that the fiber molded body (1) is transferred to a compression mold (17) after removal from the suction mold (2), and a counter mold (15) is pressed against the fiber molded body (1) arranged in the compression mold (17). Method according to claim 7, characterized in that the removal and / or transfer of the fiber molded body (1) from the suction mold (2) to the compression mold (17) takes place by means of a transfer mold (15). Method according to one of the preceding claims, characterized in that the suction mold (2), the compression mold (17), and / or the counter mold (15) are heated. Method according to one of the preceding claims, characterized in that the fiber molded body (1) is additionally coated with a coating solution.Device for producing a fiber molded body with. - a chamber (5), - at least one device for mixing fiber material with air to produce a fiber material-air mixture (6) in the chamber (5), - at least one supply device (10) for water in the form of droplets and / or water vapor, - at least one suction form (2) which can be introduced into the chamber (5) and has a porous wall (4) for depositing and compacting fibre material from the fibre material- material-air mixture (6), wherein the contour of the porous wall (4) corresponds to the contour of the fiber molded body to be produced and - at least one suction device. Device according to claim 11, characterized in that the device for mixing the fiber material with air comprises a propeller and / or a vibrating membrane. Device according to one of claims 11 or 12, characterized in that it comprises at least one of the following features: - at least one suction mold carrier (3) which can be driven by means of an actuator; - separate storage containers (7, 9, 11, 13) for the fiber material, water, sugar, wax and / or lipids; - at least one device for heating the fibre material, the water, the sugar and / or wax; - at least one device for mixing water, sugar and / or wax with air; - at least one transfer mold (15); - at least one transfer mold carrier (16) which can be driven via an actuator; - at least one pressing mold (17) and at least one counter-mold (15) for pressing the fiber molded body; - at least one device for heating the suction mold, the compression mold and / or the counter mold; - at least one coating station for coating the fiber molded body; - at least one control unit.

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