Technique for shaping three-dimensional articles from biomaterial

Abstract

The invention relates to a mould (100) for shaping at least one three-dimensional article (2) in a two-dimensional layer (1) of biomaterial. The mould (100) comprises: a first mould half (120) having at least one mould insert (122) that has a cavity (124); a second mould half (140) having at least one mould die (142); and a heating device (160), which is designed to heat the mould insert (122) and / or the mould die (142) to a mould temperature. The mould (100) is designed to mould, in a closed state of the mould (100), by providing at least one shaping pressure and the mould temperature, at least one three-dimensional article (2) in the biomaterial layer (1). The at least one mould insert (120a) and / or the at least one mould die (142) are / is designed to remove moisture escaping from the material layer (1) during the moulding process from the closed mould (100). The invention also relates to a moulding machine for receiving the above-mentioned mould (100), and to a moulding method.

Description

[0001] Technique for forming three-dimensional articles from biomaterial

[0002] Technical area

[0003] The present invention relates to the production of three-dimensional articles made of biomaterial. Specifically, the invention relates to a mold and a molding method for producing at least one three-dimensional article from a two-dimensional layer of biomaterial.

[0004] State of the art

[0005] The production of three-dimensional packaging items, such as containers, bowls, cups, or capsules, made of plastic for portioning and packaging food is well known. Polyethylene terephthalate (PET), polystyrene (PS), or polypropylene (PP) can be used as plastic materials, for example. Injection molding or forming processes, such as thermoforming, can be used to produce such packaging items.

[0006] Forming processes such as thermoforming have the advantage that plastic articles made of thermoplastic material can be produced cost-effectively in large quantities and with good quality. For article formation, molds are provided that have a plurality of mold cavities into which a two-dimensional layer of thermoplastic material (for example, a plastic film or sheet) is molded. Thus, a plurality of articles can be formed simultaneously in one molding cycle. Such molds are known, for example, from the publications EP 1 163 996 B1, DE 20 2018 106461 U1, and US Pat. No. 6,440,354 B1.

[0007] The disadvantage of plastic items, however, is that they pollute the environment if not disposed of properly because they are not biodegradable. Due to the steady increase in plastic waste, the need to produce packaging items from biodegradable materials has grown. In recent years, there have been encouraging approaches to producing packaging items from natural fibers, particularly cellulose. For example, WO 2017 / 160217 A1 describes a technique in which cellulose fibers are preprocessed into two-dimensional layers and then formed into three-dimensional items using a molding press.

[0008] However, since natural fiber sheets do not possess the elastic properties of thermoplastic materials, producing natural fiber containers in large quantities and with consistent quality remains a challenge. Even chemical treatment of natural fiber sheets with additives often fails to achieve the elastic properties of thermoplastic plastic films. As a result, uncontrolled cracking repeatedly occurs during forming, and the resulting products often fail to meet the requirements of the packaging industry.

[0009] The object of the present invention is to provide a molding technology that enables the reliable and cost-effective production of three-dimensional packaging articles made of biodegradable material (biomaterial). In particular, the object of the present invention is to provide a molding technology, in particular a molding tool and a molding method, that enables the cost-effective production of stable packaging articles in large quantities from a sheet-like layer of natural fibers and algal components. In particular, the manufactured articles should meet the diverse requirements of the packaging industry.

[0010] Brief outline

[0011] To achieve at least one of the above-mentioned objects, according to a first aspect of the invention, a molding tool is provided which is designed to form at least one three-dimensional article in a two-dimensional layer of biomaterial. The molding tool comprises a first mold half with at least one mold insert having a cavity, a second mold half with at least one molding die, and a heating device which is designed to heat the mold insert and / or the molding die to a molding temperature. The molding tool is designed to form at least one three-dimensional article in the biomaterial layer in a closed state of the molding tool by providing at least one forming pressure and the molding temperature. Furthermore, the mold insert and / or molding die are designed to drain the moisture escaping from the biomaterial layer during the molding process from the closed molding tool.

[0012] The at least one three-dimensional article thus formed can be a packaging article. In particular, the at least one three-dimensional article can comprise a container, a tray, a cup, or a capsule. However, the at least one three-dimensional article formed can also be a lid for a container, a tray, or a cup.

[0013] A two-dimensional layer is a flat layer (for example a sheet that can be unwound from a roll or a blank). Flat means that the layer is thin in the forming direction (i.e. perpendicular to the layer surface). The two-dimensional layer is in particular flat and has a dimension (thickness) in the forming direction that is / are significantly smaller than the dimension(s) in the layer plane (i.e. in the dimensions parallel to the layer surface). A blank can be cut to the dimensions of the forming tool in the plane directions perpendicular to the forming direction / forming direction, whereas a sheet can only be cut to the dimensions of the forming tool in a plane direction perpendicular to the sheet feed direction. The sheet feed direction is the direction in which the sheet is (intermittently) fed to the forming tool during forming.The forming direction / forming direction refers to the direction in which the layer is preferentially deformed. The forming direction or forming direction is essentially perpendicular to the layer plane.

[0014] The present invention does not depend on the specific geometry / cut of the layer. Whether the layer is provided to the mold as a rollable sheet or a cut depends rather on the preprocessing of the biomaterial. Depending on the composition and properties of the biomaterial, it may be advantageous in some cases to provide the biomaterial to the mold in the form of a cut. In the following, the terms "layer," "sheet," or "cut," as well as the terms "biomaterial layer," "biomaterial sheet," or "biomaterial cut," are used synonymously or interchangeably.

[0015] The biomaterial from which the two-dimensional layer to be formed is made can be a (re)formable biomaterial with a predetermined water content (water content) that hardens (and thus becomes mechanically stable) upon the addition and removal of heat. For example, the (re)formable biomaterial can be a material made of fibers and / or algal components with a high water content (moisture content). In particular, the biomaterial from which the two-dimensional layer is made can be a material made of fibers, alginate, and water. Natural fibers or synthetically produced fibers made of biodegradable material can be used as fibers. The water content of the biomaterial can range from 50 to 85 wt.%. Alginate is a biopolymer that can be obtained from algal powder in various extraction and filtration processes.Alginate and biodegradable fibers, particularly natural fibers, mixed with water can be used to create a biodegradable "composite material" that can be processed into two-dimensional layers (sheets or blanks). These two-dimensional layers can be further processed into the desired three-dimensional articles, particularly three-dimensional packaging items, using the forming technology described here.

[0016] The closed state of the mold or closed mold refers to the state of the mold in which the two mold halves of the mold are moved towards each other in order to form (reshape) a two-dimensional layer of biomaterial arranged between the two mold halves into at least one three-dimensional article. Accordingly, the open state of the mold or open mold refers to a state in which the two mold halves of the mold are moved away from each other again. In the open state of the mold, the at least one article formed in the at least one cavity of the mold insert can be removed from the mold; in the open state, however, a new layer (for example, a new sheet section or a new blank) can also be arranged between the two mold halves to start a new forming process (reshaping process).The steps of placing a layer between the two mold halves, closing and forming / reforming the layer arranged therebetween into at least one article by the two mold halves in the closed mold, as well as opening and removing the at least one formed article from the mold define a molding cycle. The time required for an entire molding cycle determines the cycle time of the molding machine. The time required for the actual molding or reshaping process is referred to as the molding time or reshaping time.

[0017] The mold temperature is provided to the mold insert and / or the mold punch by the heating device of the molding tool. In other words, the heating device is intended to heat the mold insert and / or the mold punch to a predetermined mold temperature. For this purpose, the heating device can be thermally coupled to the mold insert and / or the mold punch. According to one variant, the heating device can comprise heating elements that are installed (integrated) in the mold insert and / or the mold punch. Additionally or alternatively, heating elements can also be arranged or installed on the tool carrier assigned to the first mold half and / or in the tool carrier assigned to the second mold half. Regardless of the specific implementation and arrangement, the heating device can heat the mold insert and / or the mold punch to a predetermined mold temperature.The mold insert and / or mold punch heated to mold temperature can in turn heat the layer to be formed to the predetermined mold temperature by transferring heat to the layer to be formed as soon as the layer comes into contact with the at least one mold insert and / or the at least one mold punch.

[0018] According to one implementation, the heating device can be designed to heat only the at least one mold insert to molding temperature. As a result, the layer to be formed is heated on that layer surface which comes into contact with the at least one mold insert (more precisely, the mold walls of the cavity of the mold insert) during forming. According to another variant, the heating device can be designed to heat the at least one mold insert and the at least one opposing mold punch to molding temperature. As a result, the layer to be formed is heated on its two opposite layer surfaces, which come into contact with the at least one mold punch and the at least one mold insert during forming. As a result, the layer to be formed is heated starting from both opposite layer surfaces, whereby rapid and particularly uniform heating of the layer to be formed is achieved.The heating removes moisture from the layer.

[0019] The mold temperature can depend on the nature of the biomaterial to be molded, in particular on the water content of the biomaterial, and can be selected or specified accordingly. For layers consisting of the above-described biomaterial made of alginate and fibers, in particular natural fibers, mold temperatures of less than or equal to 350°C, in particular mold temperatures in the range from 70°C to 250°C, preferably in the range from 80°C to 200°C, and even more preferably in the range from 90°C to 150°C, have proven effective. At these temperatures, water bound in the biomaterial is effectively removed, whereby the residual moisture content of the molded articles is significantly reduced and stable articles are obtained. In particular, it can be advantageous to keep the mold temperature constant on the at least one mold insert and / or on the at least one mold punch during a forming process.Alternatively, it may also be advantageous to adjust the mold temperature variably during the forming process, in particular to adapt it to the forming pressure that builds up in the mold during the forming process. If necessary, the mold temperature can also be set or provided differently for the at least one mold insert and the at least one forming punch.

[0020] The forming pressure can be applied to the layer to be formed via a pressure medium introduced into the closed mold and / or via the at least one forming punch of the second mold half. For example, the at least one forming punch or the second mold half with the at least one forming punch can be subjected to a pressure corresponding to the forming pressure. The pressure can be applied via the molding machine into which the mold is installed. The forming pressure can then be built up on the biomaterial layer via the pressurized forming punch. However, the combined use of forming punch and pressure medium is also conceivable in order to build up a (desired) forming pressure on the biomaterial layer. For example, the forming punch can be used to build up the forming pressure in specific areas of the biomaterial layer (e.g., in areas of the article base and / or in areas of the article side wall(s).The pressure medium can be used to generate forming pressure in hard-to-reach forming areas (e.g., in parts of the article with an undercut) and thus to reshape or shape the biomaterial layer in these hard-to-reach areas. It is also conceivable to use a pressure medium only to generate forming pressure on the biomaterial layer. In this case, the forming die can be used to pre-form the article (e.g., to pre-stretch the biomaterial layer). Compressed air, oil, wax, or any other medium suitable for generating or transferring pressure to the layer to be formed can be used as the pressure medium.

[0021] The level of the forming pressure provided by a pressure medium and / or the at least one forming die can depend on the nature of the biomaterial to be formed, in particular the (natural) fiber content and / or the water content, and can be selected or specified accordingly. For layers consisting of the above-described biomaterial made of alginate and fiber, in particular natural fiber, forming pressures in the range of 0.25 N / mm 2 up to 20 N / mm 2 , preferably in the range of 0.4 N / mm 2 up to 15 N / mm 2 proven.

[0022] In particular, the forming pressure can be continuously built up (for example, linearly or in steps) to the specified forming pressure value during forming to enable gentle forming. The provided forming pressure can, on the one hand, press the biomaterial layer into the at least one cavity of the mold insert and thus form it into the at least one desired article. On the other hand, the forming pressure can also serve to further compact the material during forming, in particular to press (press) water out of the biomaterial layer. The forming pressure can thus further reduce the water content of the molded article.

[0023] Overall, the stability of the formed article depends on the degree of compaction of the biomaterial layer and / or the residual moisture content of the formed layer material. By appropriately selecting the forming pressure and forming temperature depending on the nature of the biomaterial to be formed, in particular depending on the water content (moisture content) of the biomaterial, mechanically stable articles suitable for the packaging industry can be produced. The forming pressure is selected or specified such that the biomaterial is further compacted during the forming process, in particular that moisture bound in the biomaterial layer is removed from the biomaterial layer. Furthermore, the forming temperature is selected or specified such that, in addition to the mechanical dehumidification through compression / compaction of the biomaterial layer, thermal dehumidification (drying) of the formed biomaterial layer also takes place.It has been shown that in the case of biomaterial made of alginate and fibers (natural fibers), stable articles can only be produced by forming corresponding biomaterial layers if the material layer is mechanically and thermally dehumidified during the forming process in order to obtain articles with a sufficiently low residual moisture content.

[0024] According to one variant, the forming pressure and the forming temperature are provided as a function of the biomaterial, in particular its moisture content, such that the residual moisture content of the biomaterial in the formed three-dimensional article is less than 40 wt.%, preferably less than 30 wt.%, preferably less than 20 wt.%, preferably less than 18 wt.%, preferably less than 15 wt.%, even more preferably less than 10 wt.%. In this way, it can be ensured that the formed article remains permanently dimensionally stable and does not deform or warp during conventional use.

[0025] It has been shown that applying high forming pressures can accelerate the forming process and thus the forming cycles and forming times, provided that the moisture released (in the form of water and / or steam) by the effects of forming pressure and forming temperature is quickly removed from the closed mold. Short forming times are extremely important in the production of packaging items and are desirable for large-scale production.

[0026] The forming time can be adjusted depending on the selected forming pressure and mold temperature. The forming pressure and mold temperature are, in turn, selected depending on the biomaterial to be formed, particularly its moisture content, as described above. Thus, the forming pressure, mold temperature, and forming time are selected depending on the material to be formed in such a way that a stable article with the desired residual moisture content is obtained using the shortest possible forming time. The setting of the forming time, forming pressure, and mold temperature can be done via a control device.

[0027] The forming process can be further improved, and in particular the forming time can be further reduced, if the moisture released during the forming process (be it as water during compression / compaction of the material layer and / or as water vapor due to heating of the material layer) is drained away from the at least one cavity (and thus from the molded article formed in the cavity). To drain away the moisture, the at least one mold insert and / or the at least one mold punch can be formed at least partially from a permeable and / or porous material. The permeable material can, in particular, be moisture-permeable. Moisture-permeable here means that it allows moisture in liquid form (e.g., water) and / or gaseous form (e.g., water vapor) to pass through. The moisture released during forming can thus be drained away from the at least one cavity via the permeable and / or porous material.Preferably, a permeable and / or porous material can be used, which also has good thermal conductivity and / or heat capacity, in order to be able to transfer the heat provided by the heating device to the layer to be formed without significant delay. For example, the use of porous aluminum for the at least one mold insert and / or at least one mold punch is conceivable. Alternatively, other porous or permeable materials (e.g., porous ceramic materials, porous metal alloys) can be used, which, on the one hand, have good thermal conductivity and, on the other hand, are capable of quickly conducting moisture away from the cavity.

[0028] Since porous material (e.g. porous aluminum) generally has lower mechanical stability than non-porous material (e.g. cast aluminum), the at least one mold insert and / or the at least one mold punch can (each) be formed in two parts, with a porous first mold insert part and / or mold punch part defining the molding surfaces (contact surfaces), and a non-porous second mold insert part and / or mold punch part. In the variant described here, the porous first mold insert part forms the molding surfaces / contact surfaces of the cavity; in the same way, the porous first mold punch part forms the molding surfaces / contact surfaces of the mold punch. However, a variant is also conceivable in which the porous first mold insert part forms part of the molding surfaces / contact surfaces of the cavity (e.g. the cavity floor or the cavity side wall(s), while the remaining part of the molding surfaces / contact surfaces is formed by the non-porous second mold insert part.It is also conceivable that the porous first forming stamp part forms part of the forming surfaces / contact surfaces of the forming stamp (e.g. the stamp bottom or the stamp side wall), while the remaining part of the forming surfaces / contact surfaces is formed by the non-porous second forming stamp part.

[0029] The non-porous second mold insert part and / or die part can be formed, for example, from cast aluminum. In particular, the non-porous second mold insert part and / or die part is designed to receive the porous first mold insert part and / or die part. The non-porous second mold insert part and / or die part serves, in particular, to mechanically stabilize the at least one first mold insert part or the at least one first die part.

[0030] In addition or alternatively to the use of a porous or permeable material, the at least one mold insert and / or at least one mold punch can have at least one first channel for discharging the moisture (water and / or water vapor). The at least one first channel can open with its first end into at least one opening formed on the molding surface(s) of the at least one cavity and / or the at least one mold punch. The moisture released during the molding process (in the form of water and / or water vapor) can pass into the at least one channel via the at least one opening and be discharged (to the outside) via the at least one first channel.The cross-section (diameter) of the at least one opening is dimensioned such that moisture can be effectively drained through the at least one opening, while at the same time preventing the biomaterial to be molded from penetrating the at least one channel. This requirement is well met if the at least one opening has a diameter in the range of 0.15 mm to 1.5 mm.

[0031] According to a preferred development, the at least one mold insert and / or at least one mold punch can have a plurality of first channels, the first ends of which open into corresponding openings on the molding surface(s) (contact surface(s)) of the at least one mold insert and / or the at least one mold punch. The second ends of the plurality of first channels can open into a second channel of the at least one mold insert and / or the at least one mold punch. This second channel is a central channel arranged in the at least one mold insert and / or the at least one mold punch, via which the moisture can be further discharged to the outside.

[0032] The openings of the plurality of first channels are preferably distributed across the molding surface(s) of the at least one mold insert and / or at least one molding punch. This allows the moisture escaping from the molding surface(s) due to heating and compression of the material layer to be locally dissipated. In particular, it can be ensured that moisture is dissipated evenly across the entire molding surface(s) and that no local moisture buildup occurs. This enables a particularly controllable and uniform forming process, so that the molded article has the same residual moisture content throughout.

[0033] In addition, the molding surface(s) (contact surface(s)) of the at least one mold insert and / or the at least one mold punch can have a (slight) roughening; the roughened molding surface(s) allows the escaping moisture to be better directed to the openings of the channels. The roughening can be achieved by a surface structure created on the molding surface(s). If the at least one mold insert and / or at least one mold punch or the mold insert part and / or mold punch part defining the molding surface(s) is made of porous material, then artificial roughening of the molding surface(s) can also be omitted, since the porous material already provides a natural roughening on the molding surface(s). It is understood that the roughening of the molding surface(s) is slight, i.e.in such a way that it does not (significantly) influence the shaping of the article, but at the same time promotes the dissipation of the moisture released during the shaping process towards the channel openings.

[0034] For material layers with a high water content, it may also be advantageous to provide both the molding surface(s) of the at least one mold insert and the molding surface(s) of the at least one molding punch with openings and corresponding first channels. This allows the moisture released during the forming process to be quickly removed from both sides of the wall of the molded article formed in the at least one cavity.

[0035] The second channel and / or the at least one first channel can be realized by corresponding bores in the at least one mold insert and / or mold punch. However, it is also conceivable to produce the at least one mold insert and / or at least one mold punch using additive manufacturing processes (e.g., laser sintering). These enable cost-effective production of mold inserts and / or mold punches with channels of any desired configuration.

[0036] To assist in the removal of moisture, the molding tool can further comprise a vacuum device or be coupled to an external vacuum device. The vacuum device can be fluidically coupled to the second channel or to the at least one first channel. The vacuum device is designed to extract the moisture released during the forming process via the opening(s) and the associated first channel(s). For this purpose, the vacuum device can generate a negative pressure at the at least one first channel and / or second channel of the mold insert and / or mold punch.Since, in the closed state of the mold during the forming process, a forming pressure generally prevails in at least one cavity which is significantly higher than the normal pressure of 1013 mbar, the generation of a rough vacuum in the range from 1 mbar to 500 mbar, preferably in the range from 10 mbar to 200 mbar, in the at least one first channel and / or second channel is sufficient to effectively extract moisture.

[0037] The molding tool can further comprise a hold-down device designed to exert a hold-down force on the biomaterial layer to be formed during forming. The hold-down force can be provided by the hold-down device such that the biomaterial layer is held down at the edge of the at least one cavity during the forming process in order to prevent bulging of the biomaterial layer and the associated wrinkling of the biomaterial layer at the cavity edge during the forming process. At the same time, the hold-down force can be adjusted or provided such that the held-down biomaterial layer remains movable during the forming process, in particular can be (slightly) locally retightened during forming into the at least one cavity. This can prevent the material sheet from tearing or shearing off at the transition between the cavity edge and the cavity during forming.

[0038] The hold-down force can be variably adjusted or controlled depending on the biomaterial layer to be formed, in particular its composition and / or physical properties (e.g., elasticity, thickness). In particular, the hold-down device and the applied hold-down force can be adjusted using a (hydraulic or pneumatic) pressure medium.

[0039] Depending on the nature of the material sheet (thickness, composition, elasticity), it may be advantageous to pre-punch or punch out the material sheet near the outer edge of the article to be formed in the material sheet prior to the forming process. For this purpose, the forming tool may further comprise a punching device designed to pre-punch or completely punch out the biomaterial layer to be formed in the edge region of the article.

[0040] According to one implementation, the punching device can be configured to locally pre-punch (cut) the biomaterial layer to be formed in the circumferential direction near the cavity edge (and thus in the edge region of the article to be formed). The pre-punching of the biomaterial layer can take place before the (complete) forming of the biomaterial layer. By locally pre-punching the biomaterial layer, uncontrolled crack formation can be avoided, particularly in edge regions with high curvature (e.g., at corner regions of the article). It has been shown that high tensile stresses on the biomaterial layer to be formed occur particularly in those edge regions where the formed article has large curvatures (e.g., in corner regions).

[0041] According to another implementation, the punching device can be configured to punch out the biomaterial layer in the vicinity of the cavity edge (and thus in the edge region of the molded article) in the circumferential direction. Punching can occur after the formation of the at least one article in the biomaterial sheet. Through punching, the at least one article is completely separated from the biomaterial sheet or is only connected to it via defined retaining webs.

[0042] In both implementation variants (i.e., pre-punching or punching), the punching device can comprise at least one punching tool (e.g., a punching blade) and a counter-punching element cooperating with the at least one punching tool, which are designed to pre-punch the biomaterial layer or to punch out the at least one shaped article. However, it is also conceivable for the punching device to comprise at least one cutting punch and a cutting die for implementing a shear cut.

[0043] The first mold half and the second mold half can be designed to complement one another. According to one implementation, the first mold half can be designed as a negative mold (female mold) whose mold insert has at least one cavity, as described above. Furthermore, the second mold half with the at least one forming punch can be a positive mold (male mold) corresponding to the negative mold. In the closed state of the molding tool (i.e. when the two mold halves are moved towards one another), the at least one cavity of the negative mold, together with the at least one forming punch of the positive mold, forms a mold space that is defined (limited) by the molding surface(s) (contact surface(s)) of the at least one cavity and the at least one forming punch.The two-dimensional biomaterial layer arranged between the two mold halves can be pressed into the at least one cavity of the negative mold via the at least one forming die until, in the closed state of the molding tool, the biomaterial layer is fully in contact with the molding surface(s) of the at least one cavity and the forming die. By applying a desired forming pressure to the at least one forming die, the biomaterial layer can be further compacted, in particular, water bound in the biomaterial layer can be pressed out of the material.

[0044] According to an alternative implementation, the at least one forming punch of the second mold half can be designed as a pre-stretcher. This can be configured to pre-stretch the biomaterial layer arranged therebetween when the molding tool is closed. Pre-stretching means that the layer material is pressed into the at least one cavity by the pre-stretcher / forming punch, thereby producing a preform that has not yet reached its final shape (i.e., is not yet fully in contact with the molding surface(s) of the at least one cavity). By supplying a pressure medium, such as molding air, the preform can be pressed against the molding surface(s) of the at least one cavity and thereby assume the final article shape. In this alternative implementation, the molding tool and the forming process realized thereby correspond to a deep-drawing tool or a deep-drawing process.

[0045] In order to guide a pressure medium into the at least one cavity, the molding tool can further comprise a supply device. The supply device can be designed to (controllably) guide a pressure medium provided by a molding machine or an external pressure source into the closed molding tool, in particular into the at least one cavity of the closed molding tool. For this purpose, the pressure device can have at least one pressure channel via which the pressure medium can be supplied to the molding tool in a controlled manner. The at least one pressure channel can be fluidically coupled to an external pressure source. Alternatively, the molding tool can have its own pressure source.

[0046] Compressed air is the preferred pressure medium, as mentioned above. The use of compressed air as a pressure medium can be advantageous because it is easily available and, in particular, easy to recycle. Furthermore, many molding machines come standard with a compressed air source, which can also be used for other tasks (e.g., operating the blank holder, etc.). The disadvantage of compressed air, however, is that it can be difficult to generate high isostatic forming pressures.

[0047] If high forming pressures are required, a hydrostatic medium such as oil or wax can be used as an alternative. For example, an impregnation oil can be used to build up the required forming pressure on the biomaterial layer. The use of impregnation oil has the advantageous side effect that the material layer is not only formed into at least one article, but also simultaneously receives the desired impregnation. Alternatively, a wax (coating wax) can be used as a pressure medium, which has the advantageous side effect that the material layer is not only formed into at least one article, but also simultaneously enables the desired coating of the article wall.

[0048] If the wall of the molded article is not intended to come into contact with the pressure medium, such as oil or wax, in one implementation the molding tool can further comprise an elastic, impermeable membrane, which comes into contact with the biomaterial layer to be molded on one membrane side. On the opposite membrane side, the pressure medium, in particular the oil or wax, can then be fed into the mold space / cavity via the feed device, so that an isostatic pressure builds up on the membrane and thus also on the film to be molded. The impermeable membrane arranged between the pressure medium and the biomaterial layer prevents the biomaterial from coming into direct contact with the pressure medium.

[0049] The use of a pressure medium, such as compressed air, oil, or wax, can be advantageous overall, as it allows an isostatic forming pressure to be applied to the layer to be formed. This allows for particularly uniform forming of the biomaterial layer. Because the biomaterial is subjected to isostatic forming pressure in the molding space, the biomaterial layer can be evenly pressed / compacted in the wall and base areas of at least one cavity. As a result, the molded article experiences uniform compaction on the one hand, and on the other hand, has a uniform wall thickness in the base and wall areas.

[0050] In addition to the overpressure forming described here using the forming stamp and / or a pressure medium, it may be advantageous to further assist the forming of the biomaterial arranged between the two mold halves by applying a vacuum. For this purpose, the vacuum device described above can be used, which is provided for extracting moisture from the at least one cavity of the mold insert. The vacuum device can be designed to generate a vacuum in the at least one mold cavity via the first channel and / or second channel coupled to the vacuum device. This vacuum is suitable not only for extracting moisture but also for actively supporting the forming process.By additionally applying a forming vacuum, the forming pressure applied to the opposite side of the material layer on the punch side can be lower than in a forming process in which only a slight vacuum is applied to remove the moisture in the cavity.

[0051] According to a further aspect of the invention, the above-mentioned molding tool is used to mold at least one three-dimensional article, in particular at least one packaging article, in a two-dimensional biomaterial layer. Tests have shown that the molding tool with the above-mentioned properties is suitable for transforming biomaterial layers made of alginate, biodegradable fibers / natural fibers, and a high water content (water content of at least 50 wt.%) into stable three-dimensional articles. The three-dimensional articles thus formed can have different shapes and dimensions. Furthermore, the molded articles are mechanically stable and can be used for packaging / portioning food. For example, containers, cups, bowls, capsules (e.g., brewing capsules) for portioning food, and / or corresponding lids can be produced from the above-mentioned biomaterial using the above-described molding tool.

[0052] According to a further aspect of the invention, a molding machine is provided for producing at least one three-dimensional article from a layer of biomaterial. The molding machine comprises a molding station with an upper table and a lower table for receiving the aforementioned molding tool, wherein the upper table and / or the lower table is / are movably mounted.

[0053] The molding machine may further comprise a punching station with at least one punching tool for pre-punching the biomaterial layer and / or punching out the at least one article molded in the biomaterial layer. The at least one punching tool may comprise at least one punching blade and a counter-punching element cooperating with the at least one punching blade, which are designed for pre-punching the biomaterial layer and / or for punching out the at least one molded article. Alternatively, the at least one punching tool may comprise at least one cutting punch and a cutting die for creating a shear cut.

[0054] According to one implementation, the punching station can be a pre-punching station located upstream of the forming station. The punching station (and its punching tool) is designed to pre-punch or cut the material layer to be formed. This can be necessary if the article to be formed has an unfavorable draw ratio due to its geometry and / or low elastic properties. An unfavorable draw ratio exists, for example, if the article to be formed has a large depth relative to its diameter. In this case, the material layer can be (locally) pre-punched or cut in the edge area of ​​the article to be formed, which gives the material layer the necessary flexibility during forming of the article and thus prevents uncontrolled tearing of the material layer.According to another implementation, the punching station (and its punching tool) can be designed to completely punch out the formed articles in the material sheet. In this case, the punching station can be arranged after the forming station. The material sheet with the formed articles can be fed to the punching station and completely punched out there. Completely punched out in this context can mean that the punched article is still connected to the material layer via easily severed connecting webs. This allows the layer to be transported further to a stripping station together with the at least one punched article. In the stripping station, the at least one article is then separated from the material layer (more precisely, from the residual skeleton).However, complete punching can also mean an implementation in which the article is completely separated from the material layer and only the remaining sheet skeleton is conveyed further from the punching station.

[0055] If the article to be punched is a lid, the punching station may further comprise a hole punching tool for punching a hole in the lid (for example, to allow a straw to pass through).

[0056] The forming machine may further comprise a stripping station with at least one stripping tool for stripping the at least one punched article. The stripping station with the at least one stripping tool may be arranged downstream of the forming station and / or punching station.

[0057] According to a further aspect of the invention, a method for forming at least one three-dimensional article in a layer of biomaterial is provided. The method is carried out using the above-mentioned molding tool and comprises the following steps: arranging the layer of biomaterial between the two mold halves in the open state of the molding tool; closing the molding tool and forming at least one three-dimensional article in the material layer while providing at least one forming pressure and a forming temperature such that moisture is removed from the formed biomaterial layer; and discharging the moisture removed during forming of the biomaterial layer from the closed molding tool.

[0058] Forming pressure, forming temperature, and / or forming time can be specified depending on the nature of the biomaterial layer, in particular its water content. Accordingly, the forming step can comprise the following substeps: heating the formed biomaterial layer to a predetermined forming temperature; providing (applying) a forming pressure acting on the material layer; and maintaining the forming temperature and the forming pressure for a predetermined time (forming time). Optionally, the forming step can further comprise providing a vacuum (forming vacuum) to (support) the forming process. The forming vacuum can be provided during the forming time.

[0059] The biomaterial layer to be formed can be heated via the at least one mold insert and / or mold punch of the molding tool. For this purpose, a heating device can be provided or integrated in the mold insert and / or the mold punch, which heats the mold insert and / or the mold punch to the desired molding temperature. The mold temperature can be kept constant at a predetermined temperature during the forming process. Alternatively, the mold temperature can be varied during the forming process, for example, depending on the forming pressure to be built up, it can be successively increased (linearly or stepwise) until the predetermined mold temperature is reached.

[0060] The forming pressure acting on the biomaterial layer can be provided by the at least one forming punch and / or by a pressure medium that can be introduced into the forming tool. According to one variant, the biomaterial sheet can be pre-formed with the aid of the at least one forming punch, i.e. pre-stretched into the at least one cavity. The preform thus produced, which does not yet have the final article shape, can be further formed into the desired article by introducing a pressure medium. The pressure medium used can be, for example, compressed air (forming air), oil, wax or any other medium suitable for building up forming pressure. As described above in connection with the forming tool, an impregnating oil or coating wax can be used as the pressure medium.

[0061] The forming temperature and forming pressure are determined depending on the nature of the biomaterial layer to be formed, in particular depending on the moisture content (water content) of the biomaterial layer to be formed. For the above-mentioned biomaterial layers made of fibers (natural fibers) and alginate with a relatively high moisture content, it has been shown that forming under a forming pressure in the range of 0.25 N / mm 2 up to 20 N / mm 2 , preferably in the pressure range of 0.4 N / mm 2 up to 15 N / mm 2 and a mold temperature in the range of less than or equal to 350 °C, in particular in the range of 70 °C to 250 °C, preferably in the range of 80 °C to 200 °C, even more preferably in the range of 90 °C to 150 °C, leads to mechanically stable articles.

[0062] In particular, the applied forming pressure and the mold temperature are maintained with the mold closed for a predetermined time (hereinafter also referred to as holding time or forming time). The forming time is adjusted or specified accordingly depending on the selected forming pressure and the selected mold temperature. Generally, the forming pressure, mold temperature, and forming time are coordinated such that the biomaterial of the molded article has a residual moisture content of 40 wt.%, preferably less than 30 wt.%, preferably less than 20 wt.%, preferably less than 18 wt.%, preferably less than 15 wt.%, and even more preferably less than 10 wt.%. This ensures that the formed article remains permanently dimensionally stable and does not deform or warp during conventional use.

[0063] By applying the forming pressure and the mold temperature, moisture (in the form of water and / or water vapor) is continuously removed from the biomaterial layer during the forming process. To prevent moisture buildup in the at least one cavity and to enable dehumidification (drying) of the biomaterial layer during the forming process, the released moisture is continuously removed from the closed mold (from the at least one cavity). In particular, the moisture can be suctioned out of the at least one cavity in a controlled manner using a vacuum (provided by an external vacuum device).

[0064] The method may further comprise holding down the biomaterial layer to be molded during molding (forming). In particular, the holding-down step may comprise holding down the biomaterial layer in the (upper) edge region of the at least one cavity of the mold insert. In this case, the biomaterial layer can be held down in the edge region with a force (also called hold-down force) such that the biomaterial layer does not bulge in the edge region during the molding process, but at the same time can flow easily into the cavity to prevent tearing or shearing of the biomaterial layer at the transition between the edge region and the at least one cavity.

[0065] The holding-down step is performed using a holding-down device provided in the mold. The holding-down force can be adjusted or provided on the holding-down device depending on the nature and physical properties (e.g., thickness and / or elasticity) of the biomaterial layer.

[0066] The method may further comprise the step of pre-punching the biomaterial layer prior to the molding process. Additionally or alternatively, the method may comprise punching out the at least one article molded into the biomaterial layer to separate the at least one article from the biomaterial layer.

[0067] Short description of the characters

[0068] Further details and advantages of the invention will be further described with reference to the non-limiting embodiments shown in conjunction with the figures. They show:

[0069] Figures 1a and 1b show molds according to the present invention; Figures 2a and 2b show further molds according to the present invention;

[0070] Figures 3a and 3b show further molding tools according to the present invention;

[0071] Figure 4 shows a molding tool with a feeding device for feeding a

[0072] printing medium;

[0073] Figure 5 is a flowchart illustrating a method for forming a two-dimensional sheet of biomaterial according to the present invention;

[0074] Figures 6a to 6d show a sequence of the method shown in Figure 5 using a mold according to the invention; and

[0075] Figure 7 is a schematic representation of a molding machine incorporating one of the molding tools described above.

[0076] Detailed description

[0077] Below, various embodiments of molding tools, molding machines, and forming methods according to the invention are illustrated in conjunction with the figures. The same reference numerals are used for identical components, parts, and processes in the figures and in the description. It is understood that the present invention is not limited to the specific molding tools, molding machines, and forming methods described in conjunction with the figures, but merely serves to better understand the technical teaching associated with the invention.

[0078] Figures 1a and 1b show a schematic cross-sectional view of a forming tool 100 according to the present invention. The forming tool 100 is designed to transform a two-dimensional layer into at least one article (or several articles in the case of a multiple-use tool). Article can be a packaging article, such as a cup, a container, a capsule, a bowl, or a corresponding lid, which is produced for portioning food. A two-dimensional layer is a sheet-like layer that is essentially planar and has a small thickness in a direction perpendicular to the layer surface. As mentioned above, the layer can be provided to the forming tool 100 as a blank or as an unrollable sheet (not shown in Figures 1a and 1b).

[0079] According to the present invention, biomaterial refers to a biodegradable material. According to the present invention, a biomaterial can primarily be used that is moldable and remoldable and hardens upon the addition of heat and removal of water. Biomaterial with such properties can be formed from fibers and components from algae and has a high water content. Natural fibers from renewable raw materials, particularly cellulose, can be used as fibers. However, synthetically produced fibers from biodegradable material are also conceivable. The algal component can, in particular, be alginate, which is obtained from various extraction and filter processes from algal powder. Using the alginate and the fibers / natural fibers described above, a degradable composite material can be created, which is further processed into two-dimensional layers (sheets or blanks).These sheet-like layers have a high water content in the range of 50 to 85 wt.%.

[0080] For forming such material layers, the molding tool 100 has a first mold half 120 with at least one mold insert 122. At least one mold cavity 124 (hereinafter referred to as the cavity) is formed in the mold insert 122. The first mold half 120 is supported / mounted on a plate-shaped first tool carrier 114 (lower tool carrier). Furthermore, the molding tool 100 has a second mold half 140 with at least one forming punch 142. The second mold half 140 is supported / mounted on a plate-shaped second tool carrier 112 (upper tool carrier).

[0081] The molding tool 100 shown in Figures 1a and 1b has only one cavity 124 and one forming punch 142. It is understood that the molding tool 100 can be designed as a multiple tool, which can have several (matrix-like) cavities 124 and corresponding forming punches 142. The at least one cavity 124 has contact surfaces (forming surfaces) 124a and 124b, which form the side wall and the bottom of the cavity 115. Likewise, the forming punch 142 has contact surfaces (forming surfaces) 142a, 142b, which are designed to correspond to the contact surfaces 124a, 124b of the cavity 124. The at least one cavity 124 of the mold insert 122 and the at least one mold punch 142 thus form, in the closed state of the molding tool 100, a molding space which is defined (limited) by the contact surfaces (molding surfaces) 124a, 124b, 142a and 142b and which specifies the geometric shape of the molded article.In particular, a desired forming pressure can be applied to a biomaterial layer arranged between the forming die 142 and the mold insert 122 via the at least one forming die 142. The forming pressure can be provided by a molding machine in which the molding tool 100 is installed and introduced onto the at least one forming die 142 via the second tool carrier 112.

[0082] Overall, the first mold half 120 with mold insert 122 and at least one cavity 124 with contact surfaces 124a, 124b functions as a negative mold (female mold), and the second mold half 140 with forming punch 142 and contact surfaces 142a, 142b functions as a corresponding positive mold (male mold). They can be used for pressure forming a biomaterial layer arranged therebetween. For the sake of completeness, it should be noted that the molding tool 100 is shown in Figures 1a and 1b without a biomaterial layer arranged therein; furthermore, the molding tool 100 is shown in a partially closed state.

[0083] The molding tool 100 further comprises a heating device 160. The heating device 160 is designed to heat the at least one mold insert 122 and the at least one molding die 142 to a desired molding temperature. For this purpose, the heating device 160 can comprise heating elements 162, which are accommodated in the at least one mold insert 122 and in the at least one molding die 142. The biomaterial layer can be heated to the desired molding temperature via the heated mold insert 122 and the molding die 142. To enable rapid heat transfer between the heating device 160 and the biomaterial layer, the heating elements 162 are preferably arranged near the respective contact surfaces 124a, 124b, 142a, 142b. Furthermore, the at least one molding die 142 and the mold insert 122 can be made of a material with high thermal conductivity, preferably aluminum or another thermally conductive metal or metal alloy.

[0084] The molding tool 100 further comprises a hold-down device 180. The hold-down device 180 is designed to hold the biomaterial layer down in the edge region of the at least one cavity 124 during the forming process. The hold-down force provided by the hold-down device 180 can be selected such that the biomaterial layer is securely held down during the forming process in order to prevent the material layer from wrinkling in the edge region during the forming process. At the same time, the hold-down force provided is selected such that the biomaterial layer remains movable in the edge region of the cavity 124, so that the biomaterial layer can be easily pulled back into the at least one cavity 124 during forming.

[0085] The at least one forming punch 142 and the at least one forming insert 122 further each have at least one first channel 152, 154, the first end of which opens into at least one corresponding opening 152a, 154a on the contact surfaces 142a, 142b and 124a, 124b. Furthermore, the at least one forming punch 142 and the at least one forming insert 122 each have a second channel 156, which is fluidically coupled to the second end of the respective first channels 152, 154. Moisture (in the form of water and / or water vapor) escaping during the forming of the material layer can be diverted from the forming chamber (to the outside) via the at least one first channel 152, 154 with corresponding openings 152a, 154a provided in the forming punch 142 and the forming insert 122, and the second channel 156.

[0086] In the molding tool 100 shown in Figures 1a and 1b, only first channels 152, 154 with openings 152a, 154a are provided on the bottom contact surface 124b, 142b of the at least one molding die 142 and the at least one molding cavity 124. It is understood that further first channels 152, 154 with associated openings 152a, 154a can be provided on the corresponding wall contact surfaces 124a, 142a in order to even better dissipate moisture escaping from the biomaterial layer during forming.

[0087] The first channels 152, 154 can be realized as bores with a small cross-section (diameter) in the mold insert 122, which open into the cavity 124 at the openings 152a, 154a. The diameter (cross-section) of the bores 152, 154 and the associated openings 152a, 154a are selected such that moisture can be easily drained through them, while at the same time preventing the biomaterial to be molded from penetrating the channels / bores 152, 154. This condition is well met if the bores 152, 154 or the openings 152a, 154a have diameters in the range of 0.15 mm to 1.5 mm.

[0088] In the molding tool 100 shown in Figure 1b, the second channel 156 of the at least one mold insert 122 and the at least one mold punch 142 is additionally coupled to a vacuum device 200. For this purpose, the vacuum device 200 can comprise a vacuum pump 202 and a vacuum line 210, 220 coupled to the respective second channel 156 of the at least one mold punch 142 and the at least one mold insert 122. The vacuum device 200 is designed to apply a vacuum to the respective second channel 156 and the first channels 152 and 154 coupled thereto. The vacuum generated by the vacuum device 200 and present in the channels 152, 154, 156 can be a rough vacuum in the range of 1 mbar to 500 mbar, preferably in the range of 10 mbar to 200 mbar, relative to 1013 mbar normal pressure. This allows the moisture released during the forming process to be quickly extracted from the closed mold 100 (the at least one mold cavity).

[0089] In a further development, the vacuum device can be designed to generate a somewhat stronger vacuum (< 200 mbar). In this case, the vacuum can be used not only to extract the released moisture, but simultaneously also as a molding vacuum to assist the deformation of the biomaterial layer. With the molding tool 100 described here according to Figures 1a and 1b, it is thus possible to deform layers of biomaterial with a relatively high moisture content, in particular to form articles of a desired geometric shape and dimension in the biomaterial layers by applying a deformation pressure and molding temperature. The deformation pressure can be transferred or exerted on the biomaterial layer via the at least one molding die 142. The molding temperature is transferred to the biomaterial layer via the heated at least one mold insert 122 and at least one molding die 142.

[0090] Due to the forming pressure, the biomaterial layer is first formed into the at least one mold cavity 124 until the biomaterial layer fully contacts the mold surfaces / contact surfaces 124a, 124b, 142a, 142b, and is then further compressed. This further compacts the biomaterial layer in the resulting molded article, in particular pressing moisture out of the biomaterial. The applied mold temperature dries ("bakes") the resulting molded article, thereby further removing moisture from the biomaterial of the molded article. The forming process, in particular the forming pressures and mold temperatures used, are described further in connection with a forming method according to the invention shown in Figure 5.

[0091] In conjunction with Figures 2a and 2b, a further molding tool 100a according to the present invention is described. Figure 2b again shows the coupling of the molding tool 100a to a vacuum device 200 for extracting moisture from the closed molding tool, as described in conjunction with Figure 1b. Reference is made to the description of Figure 1b.

[0092] The molding tool 100a shown in Figure 2a differs from the molding tool 100 shown in Figures 1a and 1b essentially in the design of the at least one mold insert 122. All other components of the molding tool 100a correspond structurally and functionally to the respective components of the molding tool 100 in Figures 1a and 1b. They are therefore provided with the same reference numerals. To avoid unnecessary repetition, reference is made to the description of the structurally identical components in connection with the molding tool 100 in Figures 1a and 1b.

[0093] The at least one mold insert 122 is formed in two parts, with an inner mold insert part 122a and an outer mold insert part 122b. The at least one mold cavity 124 with the contact surfaces / molding surfaces 124a, 124b is formed in the inner mold insert part 122a. The inner mold insert part 122a is further received in the outer mold insert part 122b. Deviating from this embodiment, the inner mold insert part 122a received in the outer mold insert part 122b can form only a part of the at least one mold cavity 124. The other part of the at least one mold cavity 124 can be formed by the outer mold insert part 122b. For example, it is conceivable that the inner mold insert part 122a forms the bottom region of the mold cavity 124 with the bottom contact surface / bottom molding surface 124b, while the outer mold insert part 122b forms the wall region of the mold cavity 124 with the wall contact surface(s) / wall molding surface(s) 124a.

[0094] Regardless of the geometric configuration described above, the inner mold insert part 122a is porous. The inner mold insert part 122a can preferably be made of porous aluminum. The porous inner mold insert part 122a is permeable, in particular moisture-permeable. Thus, the moisture released during the forming process (in liquid and / or gaseous form) can be dissipated via the porous inner mold insert part 122a. An advantage of the porous inner mold insert part 122a is that it acts like a sponge and can evenly dissipate the moisture at the contact surfaces 124a, 124b.

[0095] The outer mold insert part 122b is made of a non-porous material, preferably non-porous aluminum. Other heat-conducting metals or metal alloys are also conceivable. Heating elements 162 of the heating device 160 are installed in the outer mold insert part 122b. They serve to bring the outer mold insert part 122b and the porous inner mold insert part 122a accommodated therein to molding temperature. Furthermore, the second channel 156 is arranged in the outer mold insert part 122b, the first end of which leads to the inner mold insert part 122a. One or more first channels 154 can fluidically couple the second channel 156 to the porous inner mold insert part 122a. Thus, moisture can be drained from the closed mold 100a, in particular from the at least one cavity 154, via the porous inner mold insert part 122a, the one or more first channels 154 and the central second channel 156 during the forming process.If the second channel 156 is coupled to a vacuum device 200, a negative pressure (vacuum) can additionally be applied in the channels 154, 156, whereby the moisture can be actively sucked out of the closed mold 100b.

[0096] In conjunction with Figures 3a and 3b, a further molding tool 100b according to the present invention is described. Figure 3b again shows the coupling of the molding tool 100b to a vacuum device 200 for extracting moisture from the closed molding tool, as described in conjunction with Figure 1b. Reference is made to the description of Figure 1b.

[0097] The molding tool 100b shown in Figures 3a and 3b differs from the molding tool 100 shown in Figure 1a essentially in the design of the at least one mold insert 122. All other components of the molding tool 100b correspond structurally and functionally to the respective components of the molding tool 100 of Figures 1a and 1b. They are therefore provided with the same reference numerals. To avoid unnecessary repetition, reference is made to the description of the structurally identical components in connection with the molding tool 100 of Figures 1a and 1b.

[0098] Similar to the molding tool 100a of Figures 2a and 2b, the at least one mold insert 122 of the molding tool 100b is formed in two parts with an inner mold insert part 122a and an outer mold insert part 122b. The at least one mold cavity 124 with the contact surfaces / molding surfaces 124a, 124b is formed in the inner mold insert part 122a. The inner mold insert part 122a is further received in the outer mold insert part 122b. The molding tool 100b differs from the molding tool 100 of Figure 1a and from the molding tool 100a of Figure 2a essentially in that the inner mold insert part 122a defining the at least one cavity 124 is made of sintered material. In particular, the inner mold insert part 122a is produced by an additive manufacturing process, such as 3D printing.It is conceivable to use a powder-bed-based manufacturing process in which powder material (e.g., aluminum powder or steel powder) is applied layer by layer according to the geometric shape of the inner mold insert 122a and fused to form the desired inner mold insert 122a using a laser beam or electron beam. The advantage of additive manufacturing processes is that an inner mold insert 122a with any desired channel structure and cavities can be produced cost-effectively.

[0099] In the mold 100b shown in Figures 3a and 3b, the inner mold insert part 122a has a heavily sintered wall 122c, which, in the region of at least one cavity 124, also forms the contact surfaces 124a, 124b of the cavity 124. Furthermore, the inner mold insert part 122a has an inner region 122d, which can be honeycomb-shaped or rib-shaped, for example (indicated only by hatching in Figures 3a and 3b). Larger amounts of moisture can be temporarily stored in the cavities or channels arranged between the ribs or honeycomb walls of the inner region 122d. The cavities in the inner region 122d of the inner mold insert part 122a can be fluidically coupled to the cavity 124 via openings 154a with a small opening cross-section in the wall sections defining the contact surfaces 124a, 124b.Furthermore, the cavities in the inner region 122d of the inner mold insert part 122a can be fluidically coupled via first channels 154 to the second channel 156 formed in the second mold insert part 122b.

[0100] Thus, moisture released during the forming process in the form of liquid and / or vapor can pass through the openings 154a into the cavities formed in the interior region 122d of the mold insert 122a and from there into the second channel 156. From there, the moisture can be sucked away via the vacuum device 200 (see Figure 3b). In connection with Figure 4, a molding tool 100c is shown which differs from the molding tool 100, 100a, 100b of Figures 1a / 1b, 2a / 2b, and 3a / 3b essentially in that the second channel 156 of the at least one forming punch 142 is coupled to a feed device 300. Thus, only the second channel 156 of the at least one mold insert 122 is coupled to the vacuum device 200. All other components correspond to the components of the molds discussed in connection with Figures 1a / 1b, 2a / 2b, and 3a / 3b. Therefore, reference is made to the above description to avoid unnecessary repetition.

[0101] Although Figure 4 shows a two-part mold insert 122, as described above in connection with Figures 2a / 2b or Figures 3a / 3b, it should be understood that the at least one mold insert 122 may also be formed in one piece (block-shaped), as shown in connection with the molding tool 100 in Figures 1a and 1b.

[0102] The supply device 300 is designed to supply (provide) a pressure medium to the molding tool 100c in the closed state. For this purpose, the supply device has a pressure source 302 and a pressure line 310, which is fluidically coupled to the second channel 156 formed in the at least one molding die 140. Thus, a pressure medium can be supplied to the at least one cavity 124 via the pressure source 302, pressure line 310, the second channel 156 formed in the at least one molding die 140, and at least one first channel 154. The pressure medium supplied to the at least one cavity 124 can be used to support the shaping or forming of the biomaterial layer in the at least one cavity 124.The advantage of using a pressure medium in addition to the at least one forming punch 142 is that a uniform forming pressure can be exerted on the layer to be formed via the introduced pressure medium, whereby the forming of the layer takes place more uniformly. In particular, the introduced pressure medium can be used to build up forming pressure in areas that are difficult for the forming punch to access, such as in undercut areas provided in the wall and / or bottom area of ​​the at least one cavity 124. Compressed air can be used as the pressure medium. However, the use of another gaseous pressure medium or a liquid or viscous pressure medium, such as oil or wax, is also conceivable. The pressure source can be an external pressure source coupled via the pressure line 310. Alternatively, the pressure source can be part of the forming tool 100c.In this case, the second channel 156 arranged in the at least one forming die 142 and at least one first channel 154 function as supply channels for the pressure medium.

[0103] In a further development of the molding tool 100c shown in Figure 4, a first set of channels 152, 156 can be provided in the at least one molding punch 142 and / or the at least one mold insert 122, and a second set of channels 152, 156 can be provided in the at least one molding punch 142 and / or the at least one mold insert 122. The first set of channels 152, 156 of the at least one molding punch 142 and / or the at least one mold insert 122 can be coupled to the vacuum device 200. The second set of channels 152, 156 of the at least one molding punch 142 and / or the at least one mold insert 122 can be coupled to the pressure medium supply device 300.In this way, for example, pressure medium can be supplied to the cavity 124 via the second set of channels 152, 156 of the at least one forming die 142, while simultaneously a vacuum is applied to the first set of channels 125, 156 of the at least one mold insert for extracting moisture and / or vacuum forming. Alternatively, however, a vacuum can also be applied via the first set of channels 152, 156 of the at least one forming die 142 for vacuum forming and / or extracting moisture, while simultaneously a pressure medium is supplied to the cavity 124 via the second set of channels 125, 156 of the at least one mold insert 122. The pressure medium and vacuum can each be controlled via corresponding valves.This allows particularly flexible forming with the aid of a pressure medium and vacuum (forming vacuum), wherein, as required, the pressure medium can be supplied via the second set of channels of the at least one forming punch 142 or the at least one mold insert 122 of the at least one cavity 124, and the vacuum can be applied to the first set of channels of the at least one mold insert 122 or the at least one forming punch 142. In conjunction with Figure 5 and Figures 6a to 6e, a forming method for forming at least one three-dimensional article in a biomaterial layer will now be further described. The biomaterial layer can consist of alginate and fibers / natural fibers with a relatively high water content (50 wt.% to 85 wt.%). However, the method is not limited to this and can also be applied to other biomaterial layers by adapting the forming parameters, in particular the forming temperature and the forming pressure.

[0104] The method can be carried out with one of the molding tools 100, 100a, 100b, 100c described above and comprises the following method steps.

[0105] In a first step S10 of the method (see Figure 5 and Figure 6a), a two-dimensional layer 1 made of biomaterial is arranged or fed between the two mold halves 120, 140. This takes place when the mold 100, 100a, 100b, 100c is open, i.e. when the two mold halves are (fully) moved apart, so that a space is created between the two mold halves 120, 140, into which space the two-dimensional layer 1 can be introduced. The two-dimensional layer 1 can be fed to the mold 100, 100a, 100b, 100c via an external layer feed device. The layer feed device can, for example, be provided by a molding machine in which the mold 100, 100a, 100b, 100c is installed.

[0106] In a subsequent second step S20, the mold 100 is closed. First, the hold-down device 180 is moved against the mold insert 122 so that layer 1 located between the hold-down device 180 and the mold insert 122 is held down (see Figure 6b). The hold-down force exerted by the hold-down device 180 on layer 1 can be adjusted depending on the nature of layer 1 (thickness, elasticity). Typically, the hold-down force is selected such that layer 1 is securely held down near the cavity edge of the mold insert 122, but at the same time, it has a certain degree of mobility so that the layer can (slightly) flow into the at least one cavity 124 as it is molded into it. This prevents tearing or shearing during article molding. Subsequently, the two mold halves 120, 140 are moved toward each other in a controlled manner (see Figures 6b to 6d).In Figure 6b, the second mold half 140 has already been moved (axially lowered) so far in the direction of the first mold half 120 that the at least one molding die 142 with its contact surface 142b comes into contact with the upper side of the biomaterial layer 1.

[0107] As further shown in Figures 6c and 6d, the second mold half 140 with its at least one molding punch 142 is moved (lowered) further in the direction of the first mold half 120, whereby the layer 1 is successively formed into the at least one cavity 124.

[0108] The second mold half 140 is lowered (i.e., moved toward the first mold half 120) until the molding tool 100 is in the closed state (see Figure 6d). In the closed state, the at least one forming die 142 has reached its final position relative to the first mold half 120 and its at least one mold insert 122. By moving the molding tool 100, 100a, 100b, 100c into the closed state, the layer 1 or layer section 1 arranged therebetween is formed into the desired article 2 (see Figure 6d).

[0109] In the closed state, the at least one forming die 142 can be used to further build up forming pressure on the layer arranged between them. The forming pressure serves to further compact the biomaterial in the molded article. In particular, the applied forming pressure can press / pull moisture / water out of the biomaterial layer 1.

[0110] As described above, the at least one mold insert 122 and the at least one molding die 142 are heated. Thus, by contact of the biomaterial layer 1 with the at least one mold insert 122 and the at least one molding die 142, the biomaterial layer 1 can be brought to a desired molding temperature. The applied molding temperature additionally removes moisture from the molded article (molded article). In other words, the applied molding temperature causes the molded article (molded article) to dry and / or bake. The forming pressure and molding temperature applied to the molded article are maintained for a specific time (so-called forming time) in order to be able to remove sufficient moisture from the biomaterial layer 1. The forming temperature, forming pressure, and forming time depend on the properties, in particular the water content, of the biomaterial layer to be molded.They are selected such that the two-dimensional biomaterial layer 1 with an initially high moisture content is transformed into a stable, dry article having a relatively low residual moisture content. This residual moisture content is in the range of less than 40 wt.%, preferably less than 30 wt.%, preferably less than 20 wt.%, preferably less than 18 wt.%, preferably less than 15 wt.%, and even more preferably less than 10 wt.%.

[0111] For biomaterial layers made of alginate, fibers / natural fibers and high water content, as described above, molding temperatures of less than or equal to 350 °C, in particular molding temperatures in the range of 70 °C to 250 °C, preferably in the range of 80 °C to 200 °C, even more preferably in the range of 90 °C to 150 °C, have proven effective. Furthermore, forming pressures in the range of 0.25 N / mm 2 up to 20 N / mm 2 , preferably in the range of 0.4 N / mm 2 up to 15 N / mm2 Proven to produce stable, low-moisture articles with the residual moisture content specified above. The forming time is adjusted accordingly to the selected forming temperature and forming pressure, with higher forming pressures and higher forming temperatures generally resulting in shorter forming times. Working with forming pressures and temperatures within the ranges specified here, short forming times can be achieved for forming articles with the residual moisture content specified above.

[0112] However, the forming time also depends on how quickly the moisture escaping from the biomaterial layer 1 during forming is removed from the closed mold 100, 100a, 100b, 100c. In the molds 100, 100a, 100b, 100c according to the invention, the released moisture is quickly removed via the channels 152, 154, 156 formed in the at least one mold insert 122 and at least one mold punch 142. By coupling the channels 152, 154, 156 to a vacuum device 200, the moisture can be removed even more quickly. This further reduces the forming time.

[0113] After the at least one article 2 has been formed, the mold 100, 100a, 100b, 100c is reopened by moving the two mold halves 120, 140 apart. In the opened state, the at least one molded article 2 can be removed from the mold 100, 100a, 100b, 100c (see Figure 6e).

[0114] The molding tool 100, 100a, 100b, 100c can be controlled to carry out the method described above via the molding machine, in particular via a control device of the molding machine into which the molding tool is installed. Furthermore, at least one pressure sensor, one temperature sensor, and / or one humidity sensor can be installed or arranged in the molding tool 100, 100a, 100b, 100c. These sensors are designed to (continuously) measure the applied forming pressure, mold temperature, and / or the moisture content of the molded article during the molding process. These values ​​can be provided to the control device in real time. Thus, the forming process can be continuously monitored, and in particular, the settings for mold temperature, forming pressure, and forming time can be monitored or adjusted.

[0115] A molding machine 10 is further described in connection with Figure 7. The molding machine 10 has a molding station 20, a punching station 40, and a stripping station 60. The molding station 20 has a lower table 22 and an upper table 24 for receiving one of the above-described molding tools 100, 100a, 100b, 100c. The lower table 22 and / or the upper table 24 are movably mounted in the molding machine 10. This allows the installed molding tools 100, 100a, 100b, 100c to be moved apart (and thus opened) or toward each other (and thus closed). In the forming station 20, at least one article 2 is produced from a biomaterial layer 1 with the aid of the forming tool 100, 100a, 100b, 100c, as discussed above in connection with the forming tool 100, 100a, 100b, 100c and the method.The at least one article 2 formed with the aid of the forming tool 100, 100a, 100b, 100c is removed with the forming tool open and fed to the punching station 40 together with the biomaterial layer 1. The punching station 40 has at least one punching tool 42 and counter-punching tool 44, which are designed to punch out the at least one article 2 formed in the biomaterial layer 1. The punching tool 42 is movably mounted in the punching station 40 and cooperates with the counter-punching tool 44 to punch out the at least one article 2 from the sheet 1.

[0116] Preferably, the at least one punched-out article 2 remains connected to the biomaterial layer 1 (or to the residual skeleton) via web elements. This allows the at least one punched-out article 2 to be moved further together with the residual skeleton to the stripping station 60.

[0117] The stripping station 60 has a stacking device 62 and a stripping tool (not shown in Figure 7) which is designed to strip out the at least one punched-out article 2 which is connected to the residual grid of the biomaterial layer 1 only via the web elements.

[0118] In an implementation deviating from Figure 7, the punching station 40 of the forming machine 10 can also be configured such that the at least one article 2 is completely punched out and separated from the biomaterial layer 1. In this case, the article 2 can be removed from the punching station 40 via a removal device. The stripping station 60 can be omitted in this case.

[0119] In a further implementation of a forming machine 10 that differs from Figure 7, the punching tool for completely punching out the at least one formed article 2 can be integrated into the forming station 20 (for example in the forming tool 100, 100a, 100b, 100c). In this case, both the punching station 40 and the stripping station 60 can be omitted. In a further implementation of a forming machine 10 that differs from Figure 7, a hole-punching station downstream of the punching station 40 can be provided with a hole-punching tool for punching a hole or a slot in the at least one article. For example, the at least one article can be a lid for a container or a cup. The hole-punching tool can be provided for punching a hole or a slot in the at least one lid.Alternatively, the hole punching tool can also be integrated in the punching station 40 or in the forming tool 100, 100a, 100b, 100c (and thus in the forming station 20).

[0120] Using the molding tools, molding process, and molding machine described here, it is possible to form biomaterial layers with a high moisture content into stable articles, particularly packaging items. By actively removing the moisture released during the forming process, the forming process can be further optimized, in particular, the forming time can be significantly shortened, making this technology also usable for the production of large batches of packaging items. Furthermore, the technology described here can be used to produce mechanically stable packaging items with relatively low residual moisture from biomaterial layers with a high moisture / water content.

Claims

Patent claims 1. A molding tool (100, 100a, 100b, 100c) for molding at least one three-dimensional article (2) in a two-dimensional layer (1) made of biomaterial, comprising: a first mold half (120) with at least one mold insert (120a) having a cavity (124); a second mold half (140) with at least one molding punch (142); and a heating device (160) designed to heat the mold insert (122, 122a, 122b) and / or the molding punch (142) to a molding temperature;wherein the molding tool (100, 100a, 100b, 100c) is designed to form at least one three-dimensional article (2) in the biomaterial layer (1) by providing at least one forming pressure and the forming temperature in a closed state of the molding tool (100, 100a, 100b, 100c), and wherein the at least one mold insert (122, 122a, 122b) and / or the at least one molding stamp (142) is / are designed to drain the moisture escaping from the biomaterial layer (1) during the forming process from the closed molding tool (100, 100a, 100b, 100c); 2. Forming tool (100, 100a, 100b, 100c) according to claim 1, wherein the forming pressure acting on the biomaterial layer (1) is provided by the at least one forming punch (142) and / or by at least one pressure medium introduced into the closed forming tool (100, 100a, 100b, 100c).

3. Molding tool (100, 100a, 100b, 100c) according to claim 1 or claim 2, wherein the biomaterial layer (1) is brought to molding temperature by contact with the at least one molding punch (142) and / or the at least one molding insert (122, 122a, 122b).

4. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 3, wherein the forming pressure and the molding temperature in the molding tool (100, 100a, 100b, 100c) are provided such that the residual moisture content of the biomaterial of the at least one three-dimensional article (2) is less than 40 wt.%, preferably less than 30 wt.%, more preferably less than 20 wt.%, more preferably less than 18 wt.%.

5. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 4, wherein the molding tool (100, 100a, 100b, 100c) further comprises a vacuum device (200) or can be coupled to a vacuum device (200) which is designed to suck off the moisture discharged via the at least one mold insert (120a) and / or at least one mold punch (142).

6. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 5, wherein the at least one mold insert (122, 122a, 122b) and / or the at least one mold punch (142) has / have channels (152, 154, 156) for discharging the escaping moisture.

7. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 6, wherein the at least one mold insert (122, 122a, 122b) and / or the at least one mold punch (142) is / are formed at least partially from a moisture-permeable and / or porous material.

8. The molding tool (100, 100a, 100b, 100c) according to any one of claims 1 to 7, wherein the molding tool (100, 100a, 100b, 100c) further comprises a hold-down device (180) configured to exert a hold-down force on the biomaterial layer (1).

9. Forming tool (100, 100a, 100b, 100c) according to one of claims 1 to 8, wherein the forming tool (100, 100a, 100b, 100c) further comprises a punching device which is designed for pre-punching the biomaterial layer (1) and / or for punching out the at least one article (2) formed in the biomaterial layer (1).

10. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 9, wherein the first mold half (120) with the at least one mold insert (122, 122a, 122b) with cavity (124) is a negative mold, and the second mold half (140) with the at least one mold punch (142) is a positive mold corresponding to the negative mold.

11. Forming tool (100, 100a, 100b, 100c) according to one of claims 1 to 9, wherein the at least one forming punch (142) functions as a pre-stretcher which is provided for pre-stretching the biomaterial layer (1) into the at least one cavity (124).

12. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 11, wherein the molding tool (100, 100a, 100b, 100c) further comprises a feed device (300) which is designed to introduce a pressure medium into the closed molding tool (100, 100a, 100b, 100c).

13. The molding tool (100, 100a, 100b, 100c) according to claim 12, further comprising a membrane impermeable to the pressure medium, which is arranged in the molding tool (100, 100a, 100b, 100c) between the introduced pressure medium and the biomaterial layer (1).

14. The molding tool (100, 100a, 100b, 100c) according to any one of claims 2 to 13, wherein the vacuum device (200) is further configured to generate a vacuum to assist the shaping of the biomaterial layer (1) in the closed molding tool (100, 100a, 100b, 100c).

15. Molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 14, wherein the biomaterial is a moldable material with a predetermined water content, which hardens upon addition of heat and removal of water.

16. Use of the molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 15 for molding at least one three-dimensional article (2) in a biomaterial layer (1).

17. A molding machine (10) for producing at least one three-dimensional article (2) from a layer (1) of biomaterial, wherein the molding machine (10) comprises a molding station (20) with an upper table (24) and a lower table (22) for receiving the molding tool (100, 100a, 100b, 100c) according to one of claims 1 to 15, wherein the upper table (24) and / or the lower table (22) is / are movably mounted.

18. Forming machine (10) according to claim 17, wherein the forming machine (10) further comprises: a punching station (40) with at least one punching tool (42) for pre-punching the Biomaterial layer (1) and / or punching out the at least one article (2) formed in the biomaterial layer (1); and / or a breaking-out station (60) with at least one breaking-out tool for breaking out the at least one punched article (2) from the biomaterial layer (1).

19. A method for forming at least one three-dimensional article (2) in a layer (1) of biomaterial, the method being carried out using the mold (100, 100a, 100b, 100c) according to one of claims 1 to 15, and comprising the following steps: Arranging the biomaterial layer (1) between the two mold halves (120, 140) in the open state of the mold (100, 100a, 100b, 100c); Closing the two mold halves (120, 140) and forming at least one three-dimensional article (2) in the biomaterial layer (1) while providing at least one forming pressure and a forming temperature such that moisture is removed from the formed biomaterial layer (1); and Discharging the moisture extracted during the forming of the material layer (1) from the closed mold (100, 100a, 100b, 100c).

20. The method of claim 19, wherein the forming step comprises the following substeps: Heating the formed biomaterial layer (1) to a predetermined forming temperature; Providing a forming pressure acting on the biomaterial layer (1); and maintaining the mold temperature and the forming pressure for a predetermined time.

21. The method according to claim 20, wherein the molding temperature is provided by heating the at least one mold insert (122, 122a, 122b) and / or the at least one molding stamp (142) of the biomaterial layer (1).

22. The method according to claim 20 or 21, wherein the forming pressure is provided by the at least one forming punch (142) and / or by a pressure medium that can be introduced into the forming tool (100, 100a, 100b, 100c).

23. The method according to any one of claims 20 to 22, wherein the forming pressure and the forming temperature are provided depending on the nature of the biomaterial sheet to be formed, wherein the forming pressure provided has a pressure value in the range of 0.25 N / mm 2up to 20 N / mm 2 preferably in the range of 0.4 N / mm 2 up to 15 N / mm 2 and / or wherein the mold temperature provided has a temperature value of less than or equal to 350 °C, preferably a temperature value in the range from 70 °C to 250 °C, preferably in the range from 80 °C to 200 °C, more preferably in the range from 90 °C to 150 °C.

24. A method according to any one of claims 19 to 23, wherein the step of removing the moisture comprises extracting the moisture by means of a vacuum.

25. The method according to any one of claims 19 to 24, wherein the forming step further comprises the following substeps: Pre-stretching, with the aid of the at least one forming stamp (142), the biomaterial layer (1) into at least one preform; and completely forming, with the aid of a pressure medium, the at least one preform into the three-dimensional article (2).

26. The method according to any one of claims 19 to 25, wherein the method further comprises holding down the biomaterial layer (1) to be formed during the forming process in the forming tool (100, 100a, 100b, 100c).

27. The method according to any one of claims 19 to 26, wherein the method further comprises: pre-punching the biomaterial layer (1) before the forming process; and / or Punching out the at least one article formed in the biomaterial layer (1) (2) to separate the at least one article (2) from the material layer (1).

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