Patent Application
20240200278
Embodiments disclosed herein relate to a method for manufacturing molded parts from environmentally friendly, degradable fiber material by means of a fiber molding process in a fiber molding system, with which an additional functional layer or a layer system composed of several functional layers and/or an additional coating with a layer of fiber material can be applied to a layer of the coated surface of the molded part. Embodiments disclosed herein also relate to a fiber molding system for manufacturing molded parts according to this method and molded parts manufactured by means of this fiber molding system.
It is desirable to protect citizens and the environment from plastic pollution. In particular, single-use plastic products such as packaging materials or plastic cutlery and tableware generate a large amount of waste. In this respect, there is an increasing need for substitutes for packaging materials and containers made of plastic, with which these products can be made from recyclable plastics, materials with less plastic content or even from plastic-free materials.
The idea of using natural fibers instead of classic plastics in the extrusion process has existed at least since the early 1990s, see for example EP 0 447 792 B1. As with most fiber-processing methods, the raw material basis here is pulp. In principle, pulp consists of water, natural fibers and a binder such as industrial starch (potato starch) and has a pulpy consistency.
Since consumers are interested in a wide variety of nature-friendly products with different sizes, shapes and requirements and do not necessarily want them in very large quantities, it would be desirable to have an effective and flexible manufacturing process for environmentally-friendly molded parts made of natural fibers and a corresponding machine to be able to manufacture products (molded parts) variably and with good quality in a reproducible manner. However, molded parts made from natural fibers often show properties that are not compatible with the intended application, so that the natural fibers or molded parts require additional treatment in order to be able to be used for the respective application. It is therefore desirable to have a process that can manufacture molded parts suitable for different applications.
The present disclosure is based on an object of providing an effective and flexible manufacturing process for environmentally compatible molded parts made of natural fibers and a corresponding machine with which different products (molded parts) can be manufactured in a variable and reproducible manner with good quality, with the molded parts manufactured in this way being suitable for different applications.
The object is achieved by a method for manufacturing molded parts from environmentally friendly, degradable fiber material by means of a fiber molding process in a fiber molding system, comprising the following steps:
The term “environmentally friendly, degradable fiber material” refers to fiber materials that can be decomposed under environmental influences such as moisture, temperature and/or light, wherein the decomposition process takes place over a short period of time, for example in a range of days, weeks or a few months. For the sake of simplicity, the “environmentally friendly, degradable fiber material” is subsequently sometimes referred to as simply “fiber material”. In this case, preferably, neither the fiber material nor the decomposition products should pose an environmental hazard or contamination. Fiber materials, which in the context of the present disclosure represent an environmentally friendly, degradable fiber material, are, for example, natural fibers obtained from pulp, paper, cardboard, wood, grass, plant fibers, sugar cane residues, hemp, etc., or from the components or parts thereof and/or correspondingly recycled material. However, environmentally friendly, degradable fiber material can also refer to artificially manufactured fibers such as PLA (polylactide) etc., which correspond to the above fiber materials or have their properties. The environmentally friendly, degradable fiber material is preferably compostable. The environmentally friendly, degradable fiber material and the containers made from it are preferably suitable for introduction into the material cycle of the German organic compost bin and as a resource for biogas plants. The fiber materials and the containers made from them are preferably biodegradable in accordance with EU standard EN 13432.
The term “pulp” refers to fluid masses that contain fibers, here an environmentally friendly, degradable fiber material. The term “liquid” refers here to the state of aggregation of the pulp, the liquid pulp comprising the environmentally friendly, degradable fiber material in the form of fibers (liquid solution with the environmentally degradable fiber material). The fibers can be present as individual fibers here, as a fiber structure or as a fiber group composed of a number of connected fibers. The fibers represent the fiber material, regardless of whether they are present in the pulp as individual fibers, as a fibrous structure or as a group of fibers. The fibers are dissolved in the liquid solution in such a way that they float in the liquid solution as much as possible with the same concentration, regardless of location, for example as a mixture or suspension of liquid solution and fiber material. For this purpose, for example, the pulp can be appropriately tempered and/or circulated in some embodiments. The pulp preferably has a low material density, i.e., a proportion of fiber material of less than 8%. In one embodiment, a pulp with a proportion of environmentally friendly, degradable fiber material of less than 5%, preferably less than 2%, particularly preferably between 0.5% and 1.0%, is used in the method according to the present disclosure. This small proportion of fiber material can, inter alia, prevent clumping of the fiber material in the liquid solution, so that the fiber material can still be molded onto the suction tool with good quality. Although clumped fiber material can be sucked in by the suction tool, this would probably result in a molded part with a fluctuating layer thickness, which should be avoided in the production of the molded parts as far as possible. In this respect, the proportion of fiber material in the pulp should be small enough so that clumping or chaining does not occur or occurs only to a negligible extent. The liquid solution can be any solution suitable for the fiber molding process. For example, the pulp can be an aqueous solution containing environmentally friendly, degradable fiber material. An aqueous solution is, inter alia, an easy-to-handle solution. Here, the pulp can contain no organic binder, preferably also no non-organic binder. Without a binder, the molded parts manufactured from originally environmentally friendly, degradable fiber material can be degraded in a particularly environmentally friendly manner, since no environmentally critical binder, preferably no binder at all, is used. The elimination of binders is made possible by the combination of molding, pre-molding and hot-pressing steps, which as a whole ensure good mechanical interlinking of the individual fibers with one another in the fiber material of the molded part. The mechanical linkage is so strong that binders can be dispensed with to ensure the dimensional stability of the molded part. In one embodiment, the environmentally friendly, degradable fiber material essentially includes fibers with a fiber length of less than 5 mm. With fibers of this length, one obtains, inter alia, a good, homogeneous solution of the fiber material in the liquid solution, so that the degree of clumping of the fibers in the pulp is sufficiently low for a good, reproducible fiber molding process for the molded part. In one embodiment, the pulp is provided at a temperature of less than or equal to 80° C., preferably less than or equal to 50° ° C., particularly preferably room temperature. These low temperatures allow, inter alia, a simple process control, especially at room temperature. At higher temperatures, one can speed up the hot pressing process a little. The method of the present disclosure uses at least a first pulp reservoir with a first pulp. In other embodiments of the method according to the present disclosure, however, further pulp reservoirs (second, third, . . . ) filled with corresponding further pulps (second, third, . . . ) can also be used. The pulps can differ from one another in terms of their composition or other properties (e.g., temperature), or at least some of the pulps can have the same composition and/or the same other properties.
The fiber molding process refers to the process steps that are involved in forming the molded part, starting with the provision of the pulp, the molding of the molded part in the molding station from the fiber material of the pulp, up to the output of the finished molded part including the application of a functional layer or a layer system from a plurality of functional layers and/or coating with a further layer of fiber material to a surface to be coated of the molded part, wherein the application or coatings can be arranged at any point in the fiber molding process that is suitable for the respective layer to be applied. Depending on the embodiment, the application and coating can take place in separate stations or in a common station. Some fiber molding processes within the scope of the present disclosure provide only one application, only one coating, or both processes in the fiber molding process. Optionally, the fiber molding process according to the present disclosure additionally includes pre-molding and/or hot pressing.
The molded parts can have any shape, also referred to here as a contour, provided this shape (or contour) can be manufactured in the method according to the present disclosure or the method is suitable for producing this shape (or contour). Here, the components used for the fiber molding process can be adapted to the respective shape (or contour) of the molded part. In the case of different molded parts with different shapes (or contours), different correspondingly adapted components such as the suction tool, the suction head, if necessary the pre-pressing unit, the hot-pressing station, etc. can be used. Finished-molded parts can represent a wide variety of products, for example cups, containers, vessels, lids, bowls, portioned containers, casings or containers for a wide variety of purposes.
The suction tool refers here to the tool in which the plurality of suction heads for molding the respective molded parts are arranged, so that when the suction tool is moved, the individual suction heads in the suction tool are moved along in equal measure. The supply of media to the suction tool with a plurality of suction heads is routed in a suitable manner to the individual suction heads in the suction tool. Such a suction tool is referred to as a multi-tool because it includes a plurality of suction heads. With a multi-tool, a plurality of molded parts can be molded simultaneously from a common pulp reservoir according to the number of suction heads, which increases the throughput of the fiber molding system and thus allows the fiber-forming system to produce more economically.
The at least partial immersion of the suction tool in the pulp means that at least all of the suction heads in the suction tool come into contact with the pulp in such a way that, due to the negative pressure or suction pressure applied to the pulp with the suction tool, the fiber material is sucked out of the pulp or the pulp is sucked out with it fiber material dissolved therein is sucked in. The negative pressure can be applied to the suction tool or the suction heads via suitable connections by means of a pump system in which a suction pump is operated. For this purpose, the suction head can include a suitable gas line system, which forwards the negative pressure provided by the pump to the suction head as suction pressure. When partially dipping into the pulp, the suction tool is not only placed on the pulp, but dipped into it. The immersion depth of the suction tool in the pulp depends on the respective application and the respective fiber molding process and can differ depending on the application and possibly the molded part to be formed.
Here, the suction head can have a negative shape. A negative mold is a mold where the suction side of the suction head, i.e. the side where the fiber material is deposited due to the suction effect of the suction head and thus forms the molded part, is on the inside of the suction head, so that this inside after the suction head has been placed on the pulp or immersion of the suction head in the pulp forms a cavity into which the pulp with the fiber material is sucked (as shown in
Here, the suction head can also have a positive shape. A positive mold is a mold where the suction side of the suction head, i.e., the side where the fiber material is deposited due to the suction effect of the suction head and thus forms the molded part, is on the outside of the suction head, so that this outside after the suction head has been placed on the pulp or immersion of the suction head in the pulp does not form a cavity (as shown in
The molding of the molded part denotes a first pre-molding of the molded part, whereby this is formed from fiber material formerly randomly distributed in the pulp by means of accumulation of the fiber material on the contour of the suction head with the corresponding contour. The molded part still has a large proportion, for example 70%-80%, of liquid solution, for example water, and is therefore not yet dimensionally stable.
By molding in the molding station, a molded part is easily molded from a pulp with a fiber material, which can very flexibly deliver molded parts with a wide variety of contours, depending on the configuration of the contour of the suction head. The ratio of width or diameter to height of the molded part does not represent a limiting or critical parameter for the quality of the production of the respective molded part.
The application or coating of the functional layers, the layer system with such layers or the further layer of fiber material (hereinafter also referred to as coating) on the previously molded fiber material (molded part to be coated) serves, for example, to ensure that there is at least a partial barrier effect against material transport out of, into or through the fiber material can be avoided or at least reduced to an acceptable level. This can give the molded part, for example, a barrier effect against the penetration of moisture, water, flavorings, flavorings, odors, fats, oils, gases such as O2 and N2, light acids and all substances that contribute to the perishability of food and/or non-food-grade substances be awarded. All technologies suitable for molded parts made of fiber material can be used for the application or coating.
The method according to the disclosed embodiments provides an effective and flexible manufacturing process for environmentally compatible molded parts made of natural fibers and a corresponding machine with which different products (molded parts) can be produced variably and with good quality in a reproducible manner, with the molded parts produced in this way being suitable for different applications, for example for the food sector with appropriate barrier layers.
In a further embodiment, after molding, the method comprises the further step of pre-molding the molded part in a pre-molding station by means of a pre-pressing pressure exerted on the molded part. By means of the pre-molding station, a pre-molded-molded part that is sufficiently stable for further processing and has a further reduced proportion of liquid solution is produced in a simple manner from a mechanically still unstable molded part by means of prepressing. Pre-molding makes it possible to produce and further process the molded parts in a very reproducible manner and with great accuracy and quality with regard to the shape and layer thickness of the individual molded part sections. In one embodiment, the pre-pressing can be performed at a temperature of the pre-pressing unit of less than 80° C., preferably less than 50° C., particularly preferably at room temperature. The pre-pressing reduces the liquid content in the molded part to approx. 55%-65% and the molded part is pre-solidified in such a way that it is sufficiently dimensionally stable for tool transfer. Too high a temperature would lower the liquid content in the molded part too far, making the material too stiff for any subsequent hot pressing. In another embodiment, the pre-pressing is performed at the pre-pressing pressure between 0.2 N/mm2 and 0.3 N/mm2, preferably between 0.23 N/mm2 and 0.27 N/mm2. These moderate pressures enable the molded part to solidify gently with a moderate reduction in liquid, which is advantageous for a low-waste molding process. Preferably, during pre-molding, the suction tool with the plurality of suction heads and the molded parts located therein is pressed onto a stationary pre-pressing station with a plurality of pre-pressing lower tools adapted to the suction tool, or the pre-pressing lower tool is pressed onto a stationary suction tool. When pre-pressing, the suction tool represents the pre-pressing upper tool of the pre-pressing unit. In one embodiment, the suction tool is placed on the pre-pressing lower tool and pressed onto the pre-pressing lower tool by means of a separate pressing unit, for example a piston rod. Alternatively, the suction tool can also be attached to a robot arm, which itself exerts the pre-pressing pressure on the pre-pressing lower tool via the suction tool. The molded part remaining in the suction tool is placed on the pre-pressing lower tool for pre-pressing in such a way that it is arranged between the pre-pressing lower tool and the suction tool, so that the suction tool can be pressed onto the pre-pressing lower tool with the pre-pressing pressure.
In a further embodiment, the method comprises the further step of hot-pressing the at least formed molded part with a hot-pressing pressure after the molded part has been transferred to a hot-pressing station for final shaping of the molded part. The hot pressing in the fiber molding process can take place with or without pre-pressing. If pre-pressing is also performed, hot-pressing is performed subsequent to pre-molding. After pre-pressing has taken place, the pre-molded molded part is preferably transferred to the hot-pressing station by means of the suction tool, with the molded part being removed from the suction tool for the subsequent hot-pressing. The transfer is advantageous in that the hot pressing is performed at a high temperature with a significantly higher pressure. If the molded part were to remain in the suction tool without being transferred for hot pressing, the fiber material could get caught in the sieve of the suction tool and be removed from the suction tool only with difficulty, possibly only with damage after hot pressing. In addition, the sieve could be damaged by the high pressure, so that the suction tool would then no longer be functional. The transfer can take place in such a way that the molded part or parts are transferred from the suction tool to the hot-pressing station either passively by depositing them or actively by means of an ejection pressure in the suction tool against the molded parts. With the hot-pressing of the pre-pressed molded part with a hot-pressing pressure, the molded part is finally shaped with a further reduction in the proportion of the liquid solution in the molded part, for example to below 10%, preferably to approximately 7%, after which it is then stable and dimensionally stable. Hot pressing avoids lengthy drying procedures in drying ovens. Preferably, the hot press bottom and top tools are made of metal. The hot pressing is performed at the hot-pressing pressure higher than the pre-pressing pressure, for example at a hot-pressing pressure between 0.5 N/mm2 and 1.5 N/mm2, preferably between 0.8 N/mm2 and 1.2 N/mm2. The ho-pressing pressure can be applied for a pressing time of less than 20 s, preferably more than 8 s, particularly preferably between 10 and 14 s, even more preferably 12 s. The hot-pressing pressure is applied hydraulically to the hot-pressing station, for example via a piston rod, this piston rod pressing, for example, on the hot-pressing upper tool, which in turn presses on the stationary hot-pressing lower tool, with the molded part in between. The arrangement could also be reversed. With the hot-pressing station, a pre-molded and still slightly variable molded part can be produced in a simple manner by means of hot-pressing, using hot-pressing, a finished molded part can be produced with a significantly reduced proportion of liquid solution for further processing. The hot-pressing station makes it possible to produce and further process the molded parts in a very reproducible manner and with great accuracy and quality in terms of shape and layer thickness of the individual molded part sections. In particular, the combination of pre-pressing and hot-pressing enables a particularly reproducible production of molded parts with particularly good quality and a particularly low amount of rejects. In this way, end-stable molded parts can be produced particularly easily, effectively and flexibly from environmentally friendly, degradable fiber material with good quality and good reproducibility. The target contour of the molded part and thus the corresponding shaping components is preferably designed in such a way that all surfaces of the molded part have an angle α of at least 3 degrees to the pressing direction during hot pressing. For example, a surface perpendicular to the pressing direction (maximum pressure) has an angle α=90 degrees. This ensures that the hot press pressure can be applied to all surfaces of the molded part. No pressure can be applied to surfaces parallel to the direction of pressure during hot pressing.
In a further embodiment, the surface to be coated can be an outer surface of the molded part and/or an inner surface of the molded part. Thus, depending on the application, the molded part or the content of the molded part can be protected by applying or applying a coating from the outside and/or inside.
In a further embodiment, the application comprises conditioning the surface to be coated and subsequent coating of the conditioned surface. The conditioning prepares the fiber material on its surface or even in its depth for a subsequent coating, which facilitates the application of layers, for example improves the adhesion or the functionality of such layers and/or stabilizes them over a longer period of time.
In a further embodiment, during conditioning, the surface to be coated is coated, preferably sprayed, with a material smoothing and/or filling the surface, preferably a biocompatible material, in preparation for the coating step. Surfaces with a lower texture, in particular smoothed surfaces, can be more easily subsequently coated with functional layers or such layer systems.
In a further embodiment, the molded part is sprayed with wax and/or paint or coated with PTFE during conditioning. The term “wax” refers to an organic compound that melts above about 40° C. and then forms a low-viscosity liquid. This makes waxes easy to apply to a surface by spraying. Their low melting temperature makes it possible to saturate or impregnate fiber materials with wax. The process of penetrating the wax into the fiber material can be supported by elevated temperatures above the melting point. Waxes are almost insoluble in water but soluble in organic, non-polar media. Waxes can be very different in their chemical composition and origin and can be waxes according to the definition of the German Society for Fat Science. The waxes that can be used here can be natural waxes such as animal waxes (e.g. wool wax, China wax, beeswax, tallow or insect wax) or vegetable waxes (e.g. sugar cane wax, carnauba wax, candela wax, cork wax, guaruma wax, ouricuri wax, palm wax, esparto wax, cotton wax, rice bran wax, flax wax, Peat wax, rose wax, jasmine wax, Peethe wax, myrtle wax or waxy fig wax) and semi-synthetic or synthetic waxes (e.g. soy wax, rapeseed wax, castor wax). The wax is preferably a wax approved as a food additive. The term “paint” refers to liquid or powdered coating materials. The paint or paint layer can be applied thinly to objects and is built up into a continuous, solid film (layer) by chemical or physical processes (e.g., evaporation of the solvent). Paints usually include binders such as resins, dispersions or emulsions, fillers, pigments, solvents and additives. The paint is preferably a paint approved for foodstuffs. The term “PTFE” refers to polytetrafluoroethylene, which is a fully fluorinated polymer. The PTFE coating is usually applied and then subjected to a temperature treatment. A PTFE coating is used as a non-stick coating in many applications. PTFE is very inert. Even aggressive acids cannot attack this coating. The reason lies in the particularly strong bond between the carbon and fluorine atoms. Many substances do not succeed in breaking the bonds and reacting with PTFE. Because of its chemical inertness, PTFE is used as a coating, inter alia, to protect the coated substrates. The diverse and relatively simple compounding options enable special mixtures for various applications.
In a further embodiment, the wax is applied to the molded part as a functional layer in the layer system. For example, wax can serve as a water barrier.
In a further embodiment, the wax is introduced into the fiber material by means of a temperature treatment of the molded part. The hot-pressing temperature during hot-pressing, for example, is suitable for this. Therefore, the wax is preferably applied prior to hot pressing to allow it to penetrate into the fiber material during hot pressing. This can equally apply to correspondingly suitable paints.
In a further embodiment, the molded part is coated with the functional layer or the layer system using a physical coating process or a gas phase deposition, preferably vapor deposition, plasma coating or spraying. These coating methods are suitable, inter alia, for an effective manufacturing process.
In another embodiment, the conditioning and/or coating step is performed after the hot pressing step. This is particularly beneficial for those materials that are not amenable to conditioning at hot press temperatures. Furthermore, it is advantageous that the molded part is finally shaped after the hot pressing and is therefore particularly stable in its shape compared to earlier production stages in the fiber molding process.
In a further embodiment, the functional layer or at least one of the functional layers in the layer system or the further layer of fiber material has an at least partial barrier effect against material transport out of the fiber material, into the fiber material or through the fiber material. The barrier effect is preferably directed against the penetration of moisture, water, flavorings, essences, odorants, fats, oils and light acids and/or non-food-grade substances. Such properties are provided, for example, at least in part by paint or wax layers with a thickness of 0.02 to 0.1 mm or ceramic layers of 0.0005 to 0.02 mm (e.g., an SiOx layer). Fiber materials applied as a further layer on the molded part, which are highly ground and have a thickness of 0.1 mm to 0.3 mm, have at least such properties in part. In a further embodiment, the functional layer with a barrier effect is therefore a wax layer, paint layer or a ceramic layer, preferably an SiOx layer or a glass ceramic.
In a further embodiment, the functional layer or at least one of the functional layers in the layer system is designed in such a way that, under the conditions of use of the molded part, it releases substances that are advantageous for use of the molded part to the surroundings of the molded part. Beneficial substances are functional substances or substances that can be released from the molded part, which after release interact with the surroundings of the molded part in such a way that they have an advantageous effect on the surroundings of the molded part and/or on the molded part itself. For example, the molded part is a plant pot that is planted in the ground together with the plant. When the fiber material is broken down in the soil in an environmentally friendly manner, it releases, for example, fertilizers that were previously contained (incorporated) in the fiber material as dopants or particles. This means that separate fertilizing of the planted plant becomes superfluous, since this function is performed by the molded part itself. In another embodiment, the advantageous substances can also be substances which, after being released, allow the molded part to decompose more quickly.
In a further embodiment, the functional layer is doped with an active substance which diffuses out of the functional layer under conditions of use of the molded part. This can support various applications, for example to care for, season or change the taste of the content of the molded part. For example, this active ingredient diffuses out of the molded part after a hot liquid has been poured into it. In a further embodiment, the active ingredient is a flavoring (e.g., sugar, salt or pepper, a medicinal active ingredient, a substance that supports the environmentally friendly degradation of the molded part or an additive for the contents of the molded part.
In a further embodiment, the coating includes the following steps:
As a result, a molded part with a double fiber layer, a first layer made of fiber material from the first pulp and a second layer made of fiber material from the second pulp, can be produced in two successive suction processes. These first and second fiber materials can have different effects and, as a double layer, can provide a molded part with the desired effect (mechanical and/or chemical) both internally and externally. In this case, for example, the fiber material of the molded part molded on first can have a different fiber length, different doping, etc. than the layer of second fiber material applied as a functional layer. These steps preferably take place before pre-molding the molded part. The above steps are preferably performed prior to pre-molding if the fiber molding process includes pre-molding.
If the fiber molding process includes pre-molding, in a further embodiment the molded part is pre-molded in a common process for the molded part made from fiber material from the first pulp with a functional layer made from fiber material from the second pulp molded onto it. Thus, only one pre-molding process is required for pre-molding the molded part composed of two fiber layers. The pre-pressing tool is adapted to the shape of the molded part with fiber material with a layer of additional fiber material applied thereto.
In a further embodiment, the coating comprises the following steps:
On the one hand, the first molded part placed on the intermediate tray can be prepared, smoothed, moisture-reduced, pre-pressed for the subsequent second molded part. On the other hand, during the second immersion, the suction tool can use the same suction power under the same suction conditions as during the first immersion, since it is molded part-free during the second immersion and therefore does not have to suck in the second fiber material of the second molded part via a suction side that is already covered with fiber material of the first molded part. Thus, double layers of two fiber materials can be produced in a more defined way, inter alia. The layers of the two fiber materials preferably have a thickness that allows the first and second molded parts to be placed one on top of the other.
In a further embodiment, the coating comprises the following steps:
This combines the advantages of the above embodiment with the flexibility in terms of the layer thicknesses of the first and second molded part. By using a further suction tool, this can be adapted to the shape of the first molded part without being restricted to a specific layer thickness range. In this way, particularly thick first and/or second molded parts can be produced and still placed one on top of one another.
In a further embodiment of the method, the common molded part composed of the first and second molded parts is pre-molded in the pre-molding station by means of the pre-pressing pressure exerted on the common molded part. This inter alia achieves the same advantages as described above for pre-molding. Furthermore, the first and second molded parts are mechanically connected to one another due to the pre-pressing pressure, since the fibers of the respective fiber materials interlock with one another.
In a further embodiment, the first molded part is pre-pressed separately between the pre-pressing lower tool and the suction tool after the transfer but before it is discharged in the pre-molding station. The pressure exerted here can correspond to the pre-pressing pressure or have other values, preferably smaller values. The separate pre-pressing prepares the first molded part for the second molded part. In particular, with the same suction tool for the first and second molded parts, the outer shape of the first mold part can be pressed together so that the second mold part fits snugly over the first molded part.
In a further embodiment, the first, second and further pulps differ in their compositions, in their solvents, in their fiber materials, in their concentrations and/or in proportions and/or in the nature of any dopants. As a result, the first and second molded parts can be equipped with different functionalities, it being possible for the respective functionalities to be adapted to the respective application. For example, the outside of the common molded part can be designed to be printable, while the inside of the common molded part can have properties suitable for the contents of the molded part or is prepared for coating with further functional layers.
In a further embodiment, the functional layer made of further fiber material has a smaller layer thickness than the fiber material previously formed from the first pulp. Inter alia, this means that both fiber materials can be easily connected to one another and fit well on top of each other.
In a further embodiment, the functional layer includes the fiber material comprising a portion of a material that smoothes and/or fills the fiber material, preferably a biocompatible material. This means that the common molded part can be used for food applications without the application of further coatings.
In a further embodiment, the molded part for pre-molding is arranged between a pre-pressing lower tool and the suction tool as a pre-pressing upper tool. As a result, the molded part, which is not yet dimensionally stable at this point in time, has to be removed from the suction tool, which could possibly damage the molded part before pre-molding. The pre-pressing pressure is preferably exerted on the molded part with the suction tool, which is easy to implement in terms of design, inter alia.
The present disclosure further relates to a fiber molding system for manufacturing molded parts from environmentally friendly, degradable fiber material by means of a fiber molding process in which there is
The movement unit can comprise a robot arm that can move freely in space and on which the suction tool is mounted. This allows the movement unit to easily and flexibly move the molded parts along the fiber molding process. The manufacturing process can be accelerated or modified depending on the required production rate, inter alia. In a further embodiment, the movement unit is therefore intended to transfer the molded parts in the suction tool to the pre-pressing unit of a pre-molding station and/or to the hot-pressing station. The control unit can be implemented as a processor, separate computer system or web-based and is suitably connected to the components of the fiber molding system to be controlled, for example via data cable or wirelessly by means of WLAN, radio or other wireless transmission means. The output unit outputs the molded part for further transport or for further processing, for example to subsequent cutting, inscribing, printing, stacking and/or packing stations, for example with the aid of a conveyor belt.
With the fiber molding system according to the disclosed embodiments, an effective and flexible manufacturing process for environmentally friendly molded parts made of natural fibers and a corresponding machine are made possible, with which different products (molded parts) can be produced variably and with good quality in a reproducible manner, with the molded parts produced in this way being suitable for different applications, for example for the food sector with appropriate barrier layers.
In one embodiment, the fiber molding system also includes a pre-molding station for pre-molding the molded part by means of a pre-pressing pressure exerted on the molded part, see the above explanations for pre-molding. The pre-molding preferably takes place at room temperature.
In a further embodiment, the fiber molding system also includes a hot-pressing station for hot-pressing the at least part-molded part after transfer of the molded part to the hot-pressing station for final shaping of the molded part with a hot-pressing pressure at a hot-pressing temperature, see the above explanations for hot-pressing.
The hot pressing is preferably performed on the pre-molded molded part subsequent to the pre-molding, the pressure and temperature in the hot pressing being particularly preferably higher than in the pre-molding.
In a further embodiment, the fiber molding system also comprises a conditioning station for conditioning a surface to be coated and/or a coating station for coating the surface to be coated, preferably the surface to be coated previously conditioned with the conditioning station. The conditioning station is, for example, a spraying, steaming, painting or coating station for using other conditioning methods.
In a further embodiment, the conditioning station is designed as a spraying station for spraying the molded part with a material that smoothes and/or fills the surface, preferably a biocompatible material, particularly preferably wax and/or paint.
In a further embodiment, the conditioning station is designed for coating the molded part with PTFE.
In another embodiment, the coating station is configured to perform a physical layering process or vapor deposition, preferably vapor deposition, plasma coating, or spraying.
In a further embodiment, the coating station in the fiber molding process is arranged after the hot-pressing station. The time axis of the fiber molding process here runs from molding, if necessary, through pre-molding, followed if necessary by hot pressing, to the output of the molded part as a finally shaped product. Functional layers that are not applied as fiber material but as other layers could be impaired in their functionality or damaged by hot pressing. Such coatings are therefore preferably only applied by means of the coating station when the shaping of the molded part is finished, that is to say only on the finished molded part. Thus, the coating station is located after the hot pressing station in the fiber molding process.
In a further embodiment, the conditioning station is arranged before the hot pressing station in the fiber molding process. With regard to the time axis, reference is made to the previous paragraph. As a result, materials applied for conditioning, for example waxes that have already been applied, can penetrate well into the fiber material in the heated state during hot pressing in order to saturate it deeply with wax. This makes the fiber material smoother and/or more homogeneous for a subsequent coating. The same applies, for example, to corresponding paints. PTFE itself is heat-resistant, with the increased temperature during hot pressing promoting the sintering of the PTFE layer and thus the properties of the PTFE layer.
In a further embodiment, the fiber molding system comprises a second reservoir with a second pulp, in order to enable at least partial second immersion of the suction tool with or without molded parts already formed from the first pulp in the suction heads.
In a further embodiment, the fiber molding system comprises at least one further additional suction tool in order to mold a second molded part from a further pulp independently of a first molded part from a first pulp, with the movement unit being designed to move the second molded part in the pre-molding station onto or into the first molded part.
In a further embodiment, the fiber molding system comprises a further movement unit on which the further additional suction tool is attached. This achieves even greater flexibility in the fiber molding process. What has been described above for the other movement unit can equally apply to the further movement unit.
In a further embodiment, the movement unit or the movement units are respective robots with respective robot arms on which the suction tool or tools are arranged.
The present disclosure also relates to a molded part made of environmentally friendly, degradable fiber material manufactured with a fiber molding system according to the disclosed embodiments by means of a fiber molding process, comprising a functional layer or a layer system composed of several functional layers and/or a further layer of fiber material applied or applied to the fiber material of the molded part molded from a first pulp.
With the molded part according to the present disclosure, a variable product of good quality is provided, which is suitable for different applications, for example for the food sector with appropriate barrier layers. The molded part was also manufactured using an effective and flexible manufacturing process that is environmentally friendly and degradable.
In one embodiment, the functional layer or the layer system comprises a barrier layer, which is or comprises a wax layer, a paint layer and/or a ceramic layer, particularly preferably an SiOx layer or a glass ceramic layer.
In a further embodiment, the molded part comprises a first molded part made of the fiber material from a first pulp and a second molded part as a functional layer made from a fiber material made from a second or further pulp that differs from the first pulp, the first and second molded parts facing each other via their respective parts surfaces are connected to each other, preferably due to the pre-pressing of pre-molds.
In a further embodiment, the functional layer and/or the layer system composed of a plurality of functional layers are arranged on an outer surface and/or an inner surface of the molded part includes a first pulp and/or a second or further pulp.
In a further embodiment, the molded part is a container for food and the inner surface is coated with a layer of wax approved as a food additive, of paint approved for food, of PTFE or with an SiOx layer. In this case, the inner surface is the surface that faces the foodstuff located in the molded part.
In addition, further features, effects and advantages of the present disclosure are explained with reference to the attached drawing and the following description. Components which at least essentially correspond in terms of their function in the individual Figures are identified by the same reference symbols, with the components not having to be numbered and explained in all Figures.
In the drawing:
At this point it should be explicitly pointed out that features of the solutions described above or in the claims and/or figures can also be combined if necessary in order to also be able to implement or achieve explained features, effects and advantages cumulatively.
It goes without saying that the exemplary embodiment explained above is merely a first embodiment of the present disclosure. In this respect, the design of the disclosed embodiments is not limited to this exemplary embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019127560.1 | Oct 2019 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2020/000228 | 10/1/2020 | WO |
