Functionalization of foreign substances in lyocell method

Abstract

A process for producing a regenerated cellulosic molded body (102), wherein the process comprises feeding (52) a starting material (110) comprising cellulose and at least one foreign substance, transferring at least a part of the starting material (110) with at least a part of the at least one foreign substance into a spinning mass which additionally contains a solvent (116) for dissolving (54) at least a part of the cellulose of the starting material (110) in the solvent (116), and extruding (70) the spinning mass to form the molded body (102) and subsequent precipitation (56) in a spinning bath (191), whereby the molded body (102) is obtained, wherein the molded body (102) comprises cellulose and at least a part of the at least one foreign substance.

Description

[0001] The invention relates to a method for producing a regenerated cellulosic molded body and a use thereof.

[0002] Viscose fibers are synthetic or regenerated fibers produced using a wet spinning process known as the viscose process. The starting material for the viscose process is cellulose, which is derived from wood. From this wood, high-purity cellulose is obtained in the form of chemical pulp. In successive process steps, the pulp is first treated with sodium hydroxide, forming alkali cellulose. Subsequent reaction of this alkali cellulose with carbon disulfide produces cellulose xanthate. From this, the viscose spinning solution is created by adding more sodium hydroxide. This solution is pumped through nozzle holes into a spinning bath. There, coagulation forms a viscose filament in each nozzle hole. The resulting viscose filaments are then cut into viscose staple fibers.

[0003] Lyocell refers to a type of regenerated cellulose fiber produced using a direct solvent process. For the lyocell process, the cellulose is extracted from the raw material, wood. The resulting pulp can then be dissolved in N-methylmorpholine N-oxide (NMMO), a solvent, by dehydration without chemical modification, filtered, and subsequently extruded through spinnerets. After passing through an air gap in a bath of aqueous NMMO solution, the formed filaments are precipitated and then cut into staple fibers.

[0004] The residue-free removal of foreign substances is complex in both the lyocell and viscose processes.

[0005] It is an object of the present invention to efficiently produce cellulose products with flexibly adjustable functionality.

[0006] This problem is solved by the subject matter according to the independent patent claims. Preferred embodiments are set forth in the dependent patent claims.

[0007] According to an embodiment of the present invention, a method for producing a regenerated cellulosic molded body is provided, wherein the method comprises feeding a starting material comprising cellulose and at least one foreign substance, transferring at least a part of the starting material with at least a part of the at least one foreign substance into a spinning mass which additionally contains a solvent for dissolving at least a part of the cellulose of the starting material in the solvent, and extruding the spinning mass to the molded body and subsequent precipitation in a spinning bath (or coagulation bath), whereby the molded body is obtained, wherein the molded body comprises cellulose and at least a part of the at least one foreign substance.

[0008] According to an embodiment of the present invention, a method for producing a molded body containing cellulose is provided, wherein in the method a starting material is supplied which contains cellulose and at least one (in particular non-cellulosic) foreign substance, at least a part of the starting material is transferred with at least a part of the at least one foreign substance into a solvent in order to dissolve at least a part of the cellulose of the starting material in the solvent (in particular directly) (in particular by dehydration without chemical modification), and subsequently at least a part of the cellulose is precipitated by dilution of the at least partially dissolved starting material, whereby the molded body (for example a nonwoven fabric) or a preform of the molded body is obtained.wherein the molded body or preform comprises cellulose and at least one part of the at least one foreign substance (in particular to provide a function of the molded body or preform) of the starting material.

[0009] According to another embodiment, a starting material containing cellulose and at least one foreign substance is used to produce a molded body using the Lyocell process, wherein the molded body contains cellulose and at least part of the at least one foreign substance.

[0010] For the purposes of this application, the term "cellulose" can be understood to mean, in particular, an organic compound that is a component of plant cell walls or can be produced synthetically. Cellulose is a polysaccharide (i.e., a complex sugar). Cellulose is unbranched and typically contains several hundred to tens of thousands of β-D-glucose molecules (β-1,4-glycosidic bonds) or cellobiose units. Plants use cellulose molecules to build cellulose fibers in a controlled manner. Cellulose molecules can be aggregated using a technical process to form regenerated fibers, for example, as tear-resistant fibers.

[0011] Within the scope of this application, the term "molded body" can be understood to mean, in particular, a two- or three-dimensional geometric body that is a result of a process for producing or recovering cellulose. Specifically, a molded body can be understood to be a two- or three-dimensional object that contains or consists of cellulose and is produced from dissolved cellulose. Molded bodies can be, in particular, lyocell molded bodies, viscose molded bodies, or modal molded bodies. Typical molded bodies are filaments, fibers, sponges, and / or films. In principle, all types of cellulose molded bodies are suitable for embodiments of the invention. Fibers include both continuous filaments and cut staple fibers with conventional dimensions (for example, 38 mm in length) and short fibers.For the production of fibers, both processes with take-off devices after one or more extrusion dies and other processes, such as melt-blowing, are suitable. As an alternative to fibers, a cellulose-containing film can also be produced as a formed body, i.e., a flat and essentially homogeneous film with or made of cellulose. Films can be produced, in particular, by adjusting the process parameters of a lyocell process so that coagulation is triggered, at least partially, only after the filaments come into contact with a receiving surface. Films can be understood as flat cellulose formed bodies, the thickness of which is adjustable (for example, by selecting a number of serially arranged die bars). Other embodiments of a formed body include a woven fabric and a nonwoven fabric made of cellulose filaments, respectively.made of cellulose fibers, in particular a spunbond nonwoven fabric made of integrally fused ("merging") essentially continuous cellulose filaments ("melt blown"). A woven fabric can be understood to be, in particular, a textile sheet structure made of at least two (preferably perpendicular or nearly perpendicular) interlaced thread systems (or fiber systems), whereby threads (or fibers) in the longitudinal direction can be referred to as warp threads and threads (or fibers) in the transverse direction as weft threads. A nonwoven fabric can be described as a disordered structure (in particular, in a tangled arrangement) made of filaments or fibers or cut yarns of limited length, which are joined together to form a fiber layer or a fiber nap and are bonded together (in particular by friction). A shaped body can also be created in the shape of a sphere. Shaped bodies can also consist of particles containing cellulose, such as, in particular, beads (i.e.,Cellulose products can be provided in granules or spheres, or flakes, which can be further processed in this form. Possible cellulose products therefore also include particulate structures such as granules, spherical powders, or fibrids. A product is preferably formed by extruding a cellulose-containing spinning solution through an extrusion die, as this method allows for the production of large quantities of cellulose products with a very uniform shape. Another possible cellulose product is a sponge or, more generally, a porous product. According to exemplary embodiments, the aforementioned products can be used, for example, for the production of yarns, textiles, gels, or composite materials.

[0012] Within the scope of this application, the term "lyocell process" can be understood to mean, in particular, a process for producing cellulose using a direct solvent method. The cellulose for the lyocell process can be obtained from a starting material containing this cellulose. In the lyocell process, the starting material can be dissolved in a suitable solvent (in particular, containing tertiary amine oxides such as N-methylmorpholine N-oxide (NMMO) and / or ionic liquids, i.e., low-melting salts composed of cations and anions). Dissolution can be achieved, in particular, by dehydration and / or without chemical modification. The resulting solution, which can also be referred to as dope or spinning solution, can subsequently be pressed through one or more spinnerets in the lyocell process.Filaments formed in this way can be precipitated during and / or after their free or controlled fall through an air gap in a water-containing bath (especially in a bath with aqueous NMMO solution) and / or humidity present in the air gap.

[0013] Within the scope of this application, the term "viscose process" can be understood to mean, in particular, a process for producing cellulose using a wet spinning method. The cellulose for the viscose process can be obtained from a starting material (especially wood or wood pulp) containing this cellulose. In successive process steps, the starting material in the viscose process can first be treated with a base (for example, sodium hydroxide), resulting in the formation of alkali cellulose. Subsequent reaction of this alkali cellulose with carbon disulfide produces cellulose xanthate. From this, a viscose spinning solution can be generated by further addition of a base (especially sodium hydroxide), which can be extruded through one or more spinnerets. Viscose filaments are formed by coagulation in a spinning bath.

[0014] Within the scope of this application, the term "foreign substance" is understood to mean, in particular, at least one non-cellulosic material that remains in the manufactured molded body in addition to the cellulose (especially attached to and / or embedded in cellulose fibers and / or arranged between cellulose fibers). This may be a concentration or quantity of foreign substances that exceeds the level of minimal traces of non-cellulosic substances that would be considered unavoidable by a person skilled in the art. The one or more foreign substances may, in particular, consist at least partially of non-cellulosic fibers, such as synthetic fibers (for example, made of polyester and / or elastane), which remain in the molded body.The at least one foreign substance remaining in the molded part may alternatively or additionally contain other constituents already present in the starting material used to manufacture the molded part, for example, remnants of buttons or seams, or dyes originating from the starting material. In particular, the concentration or quantity of the one or more foreign substances remaining in the molded part may be chosen to be higher than the value that would inevitably remain as traces in the molded part due to processes for removing such foreign substances during the manufacturing process. In other words, the one or more foreign substances originating from the starting material and remaining in the molded part may be deliberately left in the molded part in a quantity that is higher than what would be unavoidable.The quantity of one or more foreign substances remaining in the molded body can be chosen such that the at least one foreign substance remaining in the molded body is present there in such a concentration or quantity that it becomes functionally apparent when the molded body or a product made from it is used, thus providing a function of the molded body or product made from it that cannot be achieved without the respective foreign substance.

[0015] According to an exemplary embodiment of the invention, a starting material is converted into a molded body containing cellulose using the lyocell process. Furthermore, during this manufacturing process, at least a portion of one or more such foreign substances is deliberately retained in the molded body, which contains at least one foreign substance (preferably already present in the starting material). While conventional methods aim to remove foreign substances to the absolute minimum technically achievable, an exemplary embodiment of the invention represents a paradigm shift in this respect and deliberately retains a certain concentration of at least one foreign substance in the finished molded body or a product manufactured therefrom by further processing, in order to influence, induce, or effect a corresponding function in the molded body or product.In other words, the process, according to an exemplary embodiment, is advantageously adapted so that a sufficient residual concentration (above a technically achievable minimum concentration) of the at least one foreign substance remains in the molded body or a product manufactured therefrom. This allows for an additional function of the molded body or product that would not be achieved, or not to this extent, without the foreign substance. In this way, a simple process can be combined with improved functionality of a manufactured cellulose molded body. The simplified manufacturing process results from the fact that no complex technical measures are required to reduce the foreign substance concentration to an absolutely technically achievable minimum.The enhanced functionality can be achieved by incorporating one or more foreign substances into the manufactured molded body, thereby imparting an additional function to the molded body or a product derived from it, or by reinforcing an existing function that would be unattainable without a sufficiently high concentration of the foreign substance. Exemplary embodiments further expand the range of possible starting materials for the lyocell process by allowing, unlike conventional approaches, the consideration of starting materials containing a significant amount of non-cellulosic foreign substances. For example, post-consumer used clothing, which has already been worn by a consumer and may contain a number of foreign substances in high concentrations in addition to cellulose, can also be used.According to one embodiment, it is unnecessary to remove the entire high quantity of foreign materials from such a starting material, since, according to this embodiment, at least some of these foreign materials can remain in the manufactured molded part to functionalize it. This improves the recyclability of cellulosic waste and promotes a resource-efficient and sustainable use of recyclable starting materials.

[0016] Further examples of the method and its use are described below.

[0017] According to one embodiment, the spinning bath contains, in particular, a mixture of water and solvent. The extruded spinning mass coagulates in the spinning bath because the solvent content is lower, and thus the cellulose falls outside the narrow solubility range of the solvent. The formed body can be, for example, a fiber, a film, or a microbead. A product, such as yarn, fabric, etc., can then be manufactured from the formed body.

[0018] According to one embodiment, precipitation can be achieved by diluting the starting material dissolved in the spinning mass with an aqueous environment in the spinning bath. In particular, the spinning bath can be a water bath, more specifically consisting essentially of water or a mixture of water and solvent (especially NMMO). To illustrate, in the Lyocell process, the water (especially a liquid bath containing water and optionally a solvent) reduces the concentration of the solvent that dissolved the cellulose to such an extent that the resulting dilute solution falls below the solubility limit of cellulose, causing the cellulose to precipitate. The coagulation medium (i.e., especially the water bath) can be essentially pure water or can contain a solvent.

[0019] According to one embodiment, the process can involve at most partial or exactly partial removal (i.e., a part is removed, and another part remains) of at least one of the at least one foreign substance. More precisely, the process can involve only exactly partial removal of at least one of the at least one foreign substance by separating only exactly a part of the at least one foreign substance from the cellulose of the starting material (particularly before precipitation, and further specifically before dissolution).According to one such embodiment, the process control during the lyocell process is adjusted so that not all removable foreign matter is deliberately removed from the starting material to produce cellulosic molded parts. Instead, the process parameters of a manufacturing apparatus are adjusted such that more than just unavoidable traces of foreign matter from the starting material remain in the manufactured molded part. For example, certain procedures for removing foreign matter can be omitted entirely or partially; for instance, the manufacturing process can be carried out without a bleaching step to remove dyes.Furthermore, it is possible to design a filter that filters a lyocell spinning solution before spinning, thereby partially removing foreign substances, in such a way (in particular, by dimensioning the openings in the filter) that a specific quantity of foreign substances (for example, foreign substances with a size below a threshold below which a filter retains spinneret particles) remains in the lyocell spinning solution and consequently in the finished molded body. In addition, it is possible, for example, to either completely omit separation steps for removing certain foreign substances or to carry out such separation steps in a limited or reduced manner. In this way, one or more foreign substances with an adjustable target concentration (in particular above an unavoidable minimum concentration) remain in the manufactured molded body.

[0020] According to one embodiment, the starting material can comprise or consist of a recyclable cellulose source, in particular being formed wholly or partially from residues from clothing production and / or from used clothing. Within the scope of this application, the term "cellulose source" can be understood to mean, in particular, a medium (especially a solid medium) that provides the cellulose material used as a basis for producing a molded body containing cellulose during a corresponding manufacturing process. An example is wood or wood pulp. Since, according to one exemplary embodiment, certain quantities of at least one foreign substance are deliberately used in the manufactured molded body to provide an additional function of the manufactured molded body, the range of starting materials for the lyocell process can be increased.The lyocell process can also utilize raw materials that are not derived from a natural resource like wood, but rather from a previously used product. The use of post-consumer clothing is particularly advantageous in this context, as such clothing contains a large reservoir of recyclable cellulose on the one hand and functionalizable foreign materials on the other (for example, synthetic plastics such as polyester or elastane, dyes, etc.).

[0021] Within the scope of this application, the term "remnants from clothing production" can be understood to mean, in particular, rejects and / or offcuts of a textile or yarn containing or consisting of cellulose, wherein these remnants arise during a process for manufacturing clothing. In the production of clothing, for example, a textile containing cellulose is produced as a starting material, from which flat pieces (for example, in the form of a T-shirt half) are then cut. The remaining remnants can, according to an exemplary embodiment, be fed back into a process for producing a molded body containing cellulose. Remnants from clothing production can therefore be a starting material containing or consisting of cellulose that can be used to recover cellulose before a consumer has used the remnants as clothing or in some other way.Residues from clothing production can consist in particular of essentially pure cellulose, especially without separate foreign bodies containing non-cellulose (such as buttons, textile printing or seams).

[0022] For the purposes of this application, the term "used clothing" can be understood to mean, in particular, clothing containing cellulose that has already been used (especially worn) by a consumer, with the aim of recovering at least some of its cellulose. Used clothing can therefore be a cellulose-containing raw material that may (but does not necessarily) contain significant amounts of foreign materials and can be used to recover cellulose after a consumer has used the used clothing as clothing or in some other way. Used clothing can, in particular, consist of a mixture of cellulose and one or more foreign materials, especially synthetic plastics (such as polyester and / or elastane), which are frequently used in clothing, and / or separate foreign bodies that do not contain cellulose (such as buttons, printed fabric, or seams).Polyesters are understood to be polymers with ester functional groups (R-[-CO-O-]-R) in their main chain. Polyesters include polycarbonates and polyethylene terephthalate. Elastane is understood to be a stretchable synthetic fiber with high elasticity. An elastane block copolymer can contain a polyurethane mass fraction of at least 85%.

[0023] According to one embodiment, the at least one foreign substance can comprise at least one from a group consisting of a dye, an optical brightener, a matting agent (in particular TiO₂), and an antimicrobial substance (in particular zinc oxide). If such a dye is retained in the molded part, and this dye was already present in the starting material, additional coloring of the manufactured molded part can be unnecessary. An optical brightener already present in the starting material can also be reused in the manufactured molded part, thus increasing the recycling rate in this respect as well. An antimicrobial substance such as zinc oxide can also be transferred from the starting material to the finished molded part and can inhibit or even eliminate unwanted growth of bacteria and the like.This is particularly advantageous for the use of the manufactured molded bodies for products that may come into contact with a user's body (for example, recycled clothing or medical devices and cosmetic items).

[0024] According to one embodiment, the at least one foreign substance can contain elastane, which is also at least partially dissolved during the dissolution of the cellulose. Elastane is used in many textiles, especially clothing, and particularly in secondhand clothing, and can be deliberately left in the cellulose-containing molded body as a foreign substance. It has been found that elastane in a recycled cellulose molded body does not cause any problems and therefore does not need to be laboriously removed from the starting material to the maximum achievable limit when a molded body is manufactured. It is even possible to impart a certain degree of elasticity to a cellulosic molded body by leaving elastane in it. In this way, molded bodies with elastic properties can also be produced.

[0025] According to one embodiment, the at least one foreign substance can be polyester, which is at least partially retained in the starting material when the latter is dissolved, particularly when it precipitates. Polyester is a foreign substance frequently found in post-consumer used clothing. According to an exemplary embodiment, at least some of this polyester can remain in the manufactured cellulose molded body. Visually, such a residual amount of polyester in the molded body can function similarly to a hot-melt adhesive, mechanically strengthening a woven or nonwoven fabric made of cellulose. By retaining at least some polyester in the cellulose molded body, a mechanically robust cellulose material can be created, which can also be endowed with thermoplastic properties.According to such an embodiment, the additional function provided by the foreign material can therefore be seen in an increased mechanical robustness or stability of the manufactured molded body.

[0026] According to one embodiment, the process can involve at least the partial removal of non-cellulosic fibers from the starting material before precipitation, particularly before dissolution. Such fibers can either be completely removed or partially retained in the molded body. Post-consumer used clothing, in particular, often contains a significant amount of non-cellulose fibers. Polyester fibers are an example. By retaining such fibers as blended fibers alongside the cellulose fibers during the process for producing cellulose molded bodies (especially cellulose fibers), separation processes can be omitted entirely or partially, and molded bodies with blended properties of cellulose and synthetic fibers can be obtained.Advantageously, such non-cellulosic fibers can be partially removed during the manufacturing process of the molded parts and partially retained. This allows the functionality of the at least one foreign material remaining in the molded part, in an adjustable quantity, to be controlled by the user.

[0027] According to one embodiment, the process can involve at least partial, and in particular complete, removal of metals from the starting material. Metals potentially contained in the starting material can advantageously be completely or partially removed, for example, to prevent allergic reactions upon contact with a user's skin (e.g., nickel). Alternatively, one or more metals can also be left in the molded part. For example, silver from the starting material can exert an antimicrobial effect in the recycled molded part. To adjust the degree of functionality of the at least one foreign substance remaining in the molded part, a portion of the metals can be removed from the starting material as foreign substances.

[0028] According to one embodiment, the process can produce cellulose-containing molded bodies without a bleaching procedure. By omitting bleaching, dyes in the raw material can also be recycled, thereby increasing the recycling rate. This improves sustainability and resource efficiency during the Lyocell process. If bleaching is omitted, pre-sorting the raw material into different color groups can be advantageously performed.

[0029] According to one embodiment, raw materials can be pre-sorted into several color groups before dissolving, and (for example, in each batch) only raw material from one of the same color groups can be dissolved. By pre-sorting the raw material, especially used clothing and / or remnants from clothing production, each raw material belonging to a specific color group can be added to the lyocell process and retained in the finished product, at least partially preserving its dyes. For example, raw material can be sorted into the color groups red, green, blue, yellow, black, white, and other residual colors. As a result of this pre-sorting, the resulting product is not an indifferent shade of gray or brown, but can have a color that corresponds to or at least closely resembles the pre-sorted color.Pre-sorting a raw material according to color groups can be accomplished fully automatically, for example, based on optical recognition of the incoming raw material and corresponding machine-controlled sorting. As a result of this pre-sorting, the dyes contained in the raw material are no longer considered disruptive foreign substances, but can instead impart their respective colors to the manufactured molded part.

[0030] According to one embodiment, the proportion of the at least one foreign substance (in particular, the total amount of non-cellulosic foreign substances in the molded part or preform) contained in the molded part or preform can be at least 0.01 percent by weight, in particular at least 0.1 percent by weight, further in particular at least 1 percent by weight, and even further in particular at least 10 percent by weight, in each case based on the total weight of the molded part or preform. The aforementioned percentage ranges of one or more foreign substances in the molded part can be retained in the molded part, either individually or in combination, for each of the foreign substances described herein (in particular a dye, a synthetic plastic such as polyester or elastane, an antimicrobial substance such as zinc oxide or silver, an optical brightener, non-cellulosic foreign fibers, etc.).The aforementioned values ​​enable sufficient functionalization of the molded body with one or more foreign substances.

[0031] In particular, the proportion of polyester present in the molded part or preform as a foreign substance originating from the starting material may be at least 0.001 percent by weight, in particular at least 0.01 percent by weight, and further, in particular at least 1 percent by weight, based on the total weight of the molded part or preform. Alternatively or additionally, the proportion of elastane present in the molded part or preform as a foreign substance originating from the starting material may be at least 0.001 percent by weight, in particular at least 0.01 percent by weight, and further, in particular at least 1 percent by weight, based on the total weight of the molded part or preform.Alternatively or additionally, the proportion of dye (in particular indigo dye from denim fabrics) present in the molded part or preform, originating from the starting material, may amount to at least 0.001 percent by weight, in particular at least 0.01 percent by weight, and further, in particular at least 1 percent by weight, based on the total weight of the molded part or preform. Alternatively or additionally, the proportion of metal oxide present in the molded part or preform, originating from the starting material, may amount to at least 0.001 percent by weight, in particular at least 0.01 percent by weight, and further, in particular at least 1 percent by weight, based on the total weight of the molded part or preform.Alternatively or additionally, the proportion of an antimicrobial substance originating from the starting material and contained in the molded part or preform can be at least 0.001 percent by weight, in particular at least 0.01 percent by weight, and further, in particular at least 1 percent by weight, based on the total weight of the molded part or preform. According to an exemplary embodiment, lyocell fibers can, for example, contain 0.004 percent by weight to 0.01 percent by weight or more of impurities after spinning.

[0032] According to one embodiment, the process can include comminution, in particular mechanical comminution, and further, in particular, shredding, of the starting material before it is dissolved in the solvent. For example, comminution can reduce the size of the starting material to fiber size. In particular, a starting material prepared in this way can also be dissolved directly without chemical pretreatment to produce a viscous spinning compound.

[0033] According to one embodiment, the starting material can be at least partially freed from crosslinking agents that crosslink the fibers of the starting material before it precipitates (preferably even before it dissolves). This can be achieved, for example, by means of an alkaline and / or acidic pretreatment, depending particularly on the type of crosslinking agent present. A lyocell fiber is a fibrillating fiber that can be crosslinked with molecules. A corresponding crosslinking agent can be problematic, as it can reduce the solubility of lyocell cellulose in lyocell solvents. At least partial removal of the crosslinking agent by means of a pretreatment (for example, by carrying out an alkaline and / or acidic step) with partial or complete dissolution of the unwanted crosslinking can increase the purity of the resulting cellulose.

[0034] According to one embodiment, the starting material can be mixed with another cellulose source before it precipitates (in particular before it dissolves in the solvent). For example, the other cellulose source can comprise at least one material from a group consisting of wood pulp, rag pulp (in particular pulp from fabric residues such as linen, rags, etc.), cotton (i.e., cellulose from a cotton plant, see Figure 5 ), cellulose produced using a lyocell process (see Figure 3 ) and cellulose produced using a viscose process (see Figure 4The starting material can also be an inhomogeneous blended fabric. The other cellulose source can be added flexibly, depending on availability. This ensures that the large-scale application of the lyocell process is not affected by any temporary shortages of a specific cellulose source. Instead, it is possible, for example, to compensate for or offset any shortfalls in recycled clothing cellulose with other cellulose sources. However, it is preferable to produce the starting material solely from recycled clothing.

[0035] According to one embodiment, the dissolution of the starting material and / or the dissolution of the cellulose source can be carried out by means of a direct dissolution process. Preferably, tertiary amine oxides are used as solvents, particularly preferably N-methylmorpholine N-oxide (NMMO).

[0036] According to one embodiment, the process can include post-processing of the formed body. Such optional post-processing can, for example, involve drying, impregnating, and / or reshaping the resulting cellulose filaments. Appropriate post-processing makes it possible to complete the production of the formed body in an application-specific manner at the end of the lyocell process.

[0037] According to one embodiment, the at least one selectively retained foreign substance in the molded body can be used to exploit a function of the at least one foreign substance for the molded body. Within the scope of the present application, the term "function" of a foreign substance in a molded body is understood to mean, in particular, a technical function (such as thermoplastic properties, elastic properties, coloring or optical brightening, antimicrobial properties) that only the molded body with the foreign substance, but not without the foreign substance, possesses. Such a function may, in particular, involve creating an effect or enhancing an effect.

[0038] According to an exemplary embodiment, the method for manufacturing the molded part can be carried out such that, based on a control command, the amount of at least one foreign substance remaining in the manufactured molded part is user-defined, in particular set higher than a minimum value achievable through process engineering. In this way, a user can flexibly adjust the level of residual concentration of the at least one foreign substance in the molded part with regard to the desired functionality of the resulting molded part.

[0039] According to an exemplary embodiment, the method can include receiving a user-generated signal to define a desired function for the molded parts to be produced and setting process parameters to determine the quantity of one or more foreign substances to be left in the molded parts to achieve the desired function. For this purpose, based on a user control command, a database containing the functions associated with individual foreign substances can be used to select one or more foreign substances suitable for achieving the desired function. After determining the desired quantity of at least one such foreign substance, the at least one process parameter can then be set so that the desired function is achieved.Possible process parameters in this context include the setting of a mechanical comminution process, the setting of a chemical cleaning process, the setting of a possible bleaching process, the setting of a filtering of lyocell spinning solution before spinning filaments, the setting of a possible process for the physical separation of constituents of a starting material, a washing process, etc.

[0040] The molded bodies produced according to the invention can be used, for example, as packaging material, fiber material, textile composites, fiber composites, nonwovens, needle felts, upholstery wadding, woven fabrics, knitted fabrics, as home textiles such as bed linen, as clothing, as filling material, flocking material, hospital textiles such as underpads, diapers or mattresses, as fabric for thermal blankets, shoe insoles, and wound dressings. Exemplary embodiments of the invention can be applied in a wide variety of technical fields as well as in medicine, cosmetics, and wellness. In medicine, for example, materials for wound treatment and wound healing can be composed of a carrier that determines the mechanical properties and a biocompatible coating material that is particularly compatible with the skin and the surface of the wound. Numerous other applications are possible.

[0041] Exemplary embodiments of the present invention are described in detail below with reference to the following figures. Figure 1 Figure 1 shows a flowchart of a process for producing a molded body containing cellulose according to an exemplary embodiment of the invention. Figure 2 shows an apparatus for producing a molded body containing cellulose according to an exemplary embodiment of the invention. Figure 3 shows a cellulose fiber produced using a lyocell process. Figure 4 shows a cellulose fiber produced using a viscose process. Figure 5 shows a natural cellulose fiber from a cotton plant.

[0042] Identical or similar components in different figures are provided with the same reference numerals.

[0043] Before describing exemplary embodiments with reference to the figures, some basic considerations will be summarized on the basis of which exemplary embodiments of the invention have been derived.

[0044] According to an exemplary embodiment of the invention, recycling residues can be functionalized in a molded body containing cellulose.

[0045] When processing recycled materials as starting material for the production of lyocell fibers, high demands are generally placed on this cellulosic starting material. Particularly in processes for processing recycled materials with high plastic content, according to exemplary embodiments of the invention, complete removal of the plastics is neither necessary nor even desirable. It has proven advantageous to retain certain proportions of foreign materials (such as plastics) in the starting material (without completely removing them), since such small quantities of plastics and other foreign materials in the lyocell dope or the lyocell spinning solution can even have positive functional properties for the lyocell fibers.For example, a certain residual elastane in the starting material, and thus also in the finished molded parts, can, according to an exemplary embodiment of the invention, create flexibility in the lyocell fibers. A residual polyurethane (PU) in the fibers can advantageously lead to thermoplastic deformability and / or increased mechanical stability of the molded parts or a product manufactured therefrom. Therefore, according to an exemplary embodiment of the invention, it is possible to deliberately forgo the complete, residue-free removal of the plastic components (such as polyethylene terephthalate (PET), polyamide (PA), polyurethane (PU), etc.), since such complete removal is difficult and resource-intensive and, due to the function provided by the foreign materials within the molded parts, is neither necessary nor desirable, as has been recognized in exemplary embodiments of the invention.In particular, small amounts of such foreign substances can even contribute positive properties to the lyocell fibers and do not cause harm.

[0046] Figure 1 shows a flowchart 50 of a process for producing a cellulose-containing or regenerated cellulosic molded body 102 (compare Figure 2 ) according to an exemplary embodiment of the invention.

[0047] As a starting material 110 (compare Figure 2Clothing that has already been worn and is no longer needed by a user, i.e., post-consumer clothing containing cellulose, can be used. In other words, before the process for producing the molded body containing cellulose 102 begins, the starting material 110 may already have been used by a consumer, see reference numeral 59. The cellulose may, for example, be present as a textile fabric, particularly with the use of other constituents (for example, synthetic plastics such as polyester and elastane). When the consumer disposes of the garment, it can be used as post-consumer starting material 110 for a process that is Figure 1 The lyocell process shown, which is described in more detail below, can be used. Alternatively or additionally, it is also possible to use a pre-consumer raw material 110 containing cellulose for such a lyocell process, for example, offcuts from clothing production.

[0048] Thus, as shown with reference numeral 52, the starting material 110 is fed into the lyocell process, whereby the recycled textile starting material 110 contains cellulose and various other foreign materials. The cellulose and the foreign materials of the starting material 110 can be present in a common solid composite (for example, as a textile fabric, fiber composite, or molded composite) when fed into the process 52. This means they can be part of one or more bodies (for example, garments or offcuts) or particles (for example, shredded or ground garments or offcuts) in the solid phase. Therefore, such a solid body or solid particles can contain a mixture of the cellulose and the foreign materials, which can thus be integrally bonded together.Thus, the starting material 110 represents a recyclable cellulose source 154, which may be formed wholly or partially from residues from clothing production and / or from used clothing. The foreign substances it contains may include a dye, an optical brightener, an antimicrobial substance such as zinc oxide, etc. Furthermore, the starting material 110 may contain elastane as another foreign substance, which can also be at least partially dissolved during the dissolution 54 of cellulose described below. Such elastane is frequently included as an additional fiber in garments to give them elasticity. The starting material 110 may also contain polyester as an additional foreign substance, which remains attached to or within the cellulose during the dissolution 54 and subsequent precipitation 56.

[0049] The following describes how, based on the cellulose-containing starting material 110, shaped bodies 102 made of lyocell cellulose and impurities that have not been removed can be produced according to an embodiment of the invention. For this purpose, the starting material 110 is fed into an apparatus 100 (see Figure 2 ) supplied for carrying out a lyocell process, see reference 52.

[0050] First, the starting material 110 can optionally be pre-sorted into several color groups (see reference numeral 64), for example, into several color-specific color groups (such as blue, red, green, yellow, black, and white) and into a residual group with color-nonspecific starting material (for example, colored textiles). This has the advantage that later only starting material 110 from a common color group is dissolved (see reference numeral 54), and thus dyes of a uniform or at least essentially uniform color can be used for a characteristic coloration of the manufactured molded bodies 102. The formation of diffuse and uncharacteristic mixed colors in the manufactured molded bodies 102 can be avoided in this way, and the dye, which is conventionally classified as an undesirable foreign substance, can be reused in the manufactured molded bodies 102 as a functional dye.Advantageously, the addition of a separate dye for coloring the molded bodies 102 or products made therefrom may then be unnecessary or only required in a reduced quantity. If, after pre-sorting 64, the dye of a color group remains in the starting material 110 and determines the color of the manufactured molded bodies 102, the cellulose-containing molded body 102 can be produced without a bleaching procedure, thus simply and in an environmentally friendly manner.

[0051] Before or after pre-sorting 64, an optional but advantageous mechanical comminution 66 of the starting material 110 by shredding can be carried out. This allows some of the contaminants, especially large non-cellulosic materials, to be removed from the starting material 110, such as buttons, seams, and prints from the used clothing that was at least partially used to produce the starting material 110. The mechanical comminution 66 allows the starting material 110 to be separated into individual fibers, for example.

[0052] It is also optionally possible (see block 68) to combine the cellulose-containing starting material 110 with other cellulose-containing materials (see further cellulose source 156 in Figure 2) jointly for the lyocell process. Thus, the starting material 110 can be mixed with another cellulose-containing starting material, see Block 68. The starting material 110 can also consist of another cellulose-containing material, such as wood or pulp extracted from it. It is therefore possible to mix the recycled starting material 110 with another cellulose-containing starting material 110. The latter can, for example, consist of rag pulp from textiles, cotton from a cotton plant, cellulose obtained from a viscose process, and / or cotton linters (i.e., significantly shorter cotton strands than, for example, the approximately 38 mm long cotton lint that grow on the seeds of a cotton plant). The proportion of used clothing in the starting material 110 can, for example, be between 3% and 100% by weight, and in particular between 10% and 80% by weight.It is particularly preferred if this proportion is 100 percent by weight.

[0053] The process can further include an optional, but advantageous, partial removal 58 of one, several, or all of the foreign substances. This removal 58 can take place directly after feeding 52, after crushing 66, or after mixing 68. It is also possible to omit the removal procedure 58 and proceed with dissolving 54 of the starting material 110 immediately after feeding 52, after pre-sorting 64, after crushing 66, or after mixing 68.

[0054] If the removal procedure 58 is performed, it may involve the partial or complete removal 60 of non-cellulosic fibers from the starting material 110, for example, if the presence of elastane or polyester fibers in the finished molded parts 102 is not desired. Alternatively or additionally, the removal procedure 58 may involve the partial or complete removal 62 of metals from the starting material 110 if the presence of metals in the molded parts 102 is not desired. Furthermore, as part of the removal procedure 58, the starting material 110 may be completely or partially freed from crosslinking agents that crosslink fibers of the starting material 110 (see reference numeral 63). If such separation of individual fibers is desired, a crosslinking agent (depending on its chemical nature) may be removed, for example, by means of an alkaline and / or acidic pretreatment.According to an exemplary embodiment of the invention, after the removal of 58, a certain adjustable proportion of foreign substances always remains in the starting material 110 to be dissolved subsequently.

[0055] Immediately after feeding 52, immediately after pre-sorting 64, immediately after mechanical comminution 66, immediately after mixing 68, or immediately after removal 58, the (pure or mixed) starting material 110 can be advantageously dissolved directly in a solvent 116 (for example, tertiary amine oxides such as N-methylmorpholine N-oxide (NMMO)) without chemical pretreatment. Such dissolution 54 can be achieved by transferring the starting material 110 (together with the impurities contained therein) into a solvent 116, thereby forming a spinning mass. More precisely, the starting material 110, pretreated as described, can be dissolved directly, particularly without chemical purification or viscosity adjustment. In this way, the manufacturing or recycling process can be carried out exceptionally simply, quickly, and in an environmentally friendly manner.Surprisingly, it has been found that, after the described pretreatment, foreign substances remaining in the starting material 110 (for example, polyester or elastane) do not interfere with the lyocell process and do not negatively affect the quality of the recovered lyocell cellulose. On the contrary, certain amounts of elastane can remain in the produced cellulose fibers without impairing their properties. Similarly, certain amounts of remaining polyester do not interfere with the product; in fact, they can even strengthen the mechanical integrity of the molded body 102 to be produced.

[0056] After dissolving the starting material 110 in solvent (preferably NMMO), the resulting lyocell spinning solution can be pressed through one or more spinnerets, producing threads or filaments of honey-like viscosity (see Block 70, which concerns this spinning or extrusion).

[0057] During and / or after these threads or filaments fall, they come into contact with an aqueous environment and are thereby diluted. The concentration of the solvent 116 in the threads or filaments is reduced in an aqueous liquid bath to such an extent that the lyocell spinning solution is converted into a solid phase of cellulose filaments. In other words, the cellulose filaments precipitate, settle, or coagulate (see reference 56). This produces a preform of the shaped body 102. The spinning mass is then extruded 70 into shaped bodies 102 by means of precipitation 56 in a spinning bath (see reference 191). Figure 2 ).

[0058] The dissolving 54, spinning or extruding 70 and subsequent precipitation 56 using a lyocell process is therefore carried out on the basis of a starting material 110 which in turn contains or consists of recyclable cellulose material and may only need to be partially freed from foreign substances.

[0059] Furthermore, the process can include post-processing 74 of the precipitated lyocell cellulose to obtain the shaped body 102 from the preform of the shaped body 110. Such post-processing can, for example, include drying, impregnating, and / or forming the obtained filaments into the final shaped body 102. For example, the shaped body 102 can be processed by the described manufacturing process into fibers, a film, a fabric, a nonwoven, a sphere, a porous sponge, or beads and then put to further use (see reference numeral 76).

[0060] The proportion of at least one foreign substance in the molded body 102 or the preform can be at least 0.1 percent by weight, based on the total weight of the molded body 102. The residual foreign substances deliberately and intentionally left in the molded body 102 can be used to exploit a function of the respective foreign substance within the context of the use of the molded body 102 or a product manufactured from it. Elastane foreign substance remaining in a molded body 102 can be used functionally to impart elasticity to the manufactured molded body 102. Polyester foreign substance remaining in the molded body 102 can be used functionally to provide the molded body 102 with thermoplastic deformability or to increase the mechanical robustness of the molded body 102 and of a product manufactured from it.

[0061] Using the procedure according to flowchart 50 according to Figure 1It is thus possible to create a simple and cost-effective manufacturing process for producing molded bodies 102, in which the requirements for removing one or more foreign substances from the starting material 110 are extremely low. Unlike conventional approaches, the described embodiment of the invention assumes that the foreign substances in the starting material 110 for producing the molded bodies 102 do not all need to be removed in the largest possible quantity as a disruptive element, but rather that a certain portion should remain in the starting material 110 and the lyocell spinning solution 104 produced therefrom in order to impart one or more desired additional functions to the manufactured molded bodies 102. These additional functions can consist of providing color, increased elasticity, increased mechanical robustness, antimicrobial properties, etc.In particular, it is helpful for a user to carry out the procedure according to flowchart 50 of . Figure 1 It is possible to influence the manufacturing process in order to equip the molded body 102 with a desired function, which can be achieved by adjusting the extent to which one or more foreign substances from the starting material 110 remain in the molded bodies 102.

[0062] Figure 2 shows an apparatus 100 for producing a cellulose-containing molded body 102 using a lyocell process according to an exemplary embodiment of the invention, which refers to Figure 1 was described.

[0063] Figure 2Figure 1 shows an apparatus 100 according to an exemplary embodiment of the invention for producing a molded body 102 containing cellulose, which can be produced, for example, in the form of a nonwoven fabric, as a fiber, film, sphere, textile fabric, sponge, or in the form of beads or flakes. Figure 2The formed body 102 is produced directly from a spinning solution 104. The latter is converted into cellulose fibers 108 as a formed body 102 by means of a coagulation fluid 106 (in particular, atmospheric moisture) and / or a coagulation bath 191 (for example, a water bath that optionally contains tertiary amine oxides such as N-methylmorpholine N-oxide (NMMO)). A lyocell process can be carried out using the apparatus 100. In this way, essentially endless filaments or fibers 108, or mixtures of essentially endless filaments and fibers 108 of discrete length, can be produced as formed bodies 102. A plurality of nozzles, each having one or more openings 126 (which can also be referred to as spinning holes), are provided to expel lyocell spinning solution 104.

[0064] How Figure 2A cellulose-based starting material 110 can be supplied to a storage tank 114 via a dosing device 113.

[0065] According to one embodiment, water can be introduced into the cellulose-based starting material 110 by means of a solvent 116 (in particular NMMO) described in more detail below. The cellulose-based starting material 110 itself can also already contain a certain residual moisture content (dry pulp, for example, often has a residual moisture content of 5% to 8% by weight). In particular, according to the described embodiment, the starting material 110 can be added directly to a mixture of water and solvent 116 without pre-moistening. Figure 2 The optional water tank 112 shown can then be omitted.

[0066] According to an alternative embodiment, the cellulose-containing starting material 110 can be additionally moistened to provide moist cellulose. For this purpose, water from an optional water reservoir 112 can be supplied to the storage tank 114 via the metering device 113. Therefore, the metering device 113, controlled by a control unit 140, can supply adjustable relative quantities of water and starting material 110 to the storage tank 114.

[0067] A suitable solvent 116, preferably tertiary amine oxides such as N-methylmorpholine N-oxide (NMMO), or an aqueous mixture of solvent 116, for example a 76% solution of NMMO in water, is contained in a solvent container. The concentration of solvent 116 can be adjusted in a concentrating unit 118 either by adding pure solvent or water. The solvent 116 can then be mixed with the starting material 110 in definable relative amounts in a mixing unit 119. The mixing unit 119 can also be controlled by the control unit 140. This dissolves the cellulose-containing starting material 110 in the concentrated solvent 116 in a dissolving unit 120 in adjustable relative amounts, thereby obtaining the lyocell spinning solution 104.The relative concentration ranges (also known as spinning windows) of the components starting material 110, water and solvent 116 in the spinning solution 104 for the production of cellulosic regenerated molded bodies according to the Lyocell process can be suitably adjusted, as is known to a person skilled in the art.

[0068] The lyocell spinning solution 104 is fed to a fiber production device 124 (which may be equipped with a number of spinning beams or jets 122).

[0069] When the lyocell spinning solution 104 is guided through the openings 126 of the jets 122, it is divided into a plurality of parallel filaments of lyocell spinning solution 104. The described process transforms the lyocell spinning solution 104 into increasingly long and thin filaments, the properties of which can be adjusted by appropriately setting the process conditions, controlled by the control unit 140. Optionally, a gas flow can accelerate the lyocell spinning solution 104 on its way from the openings 126 to a fiber receiving unit 132.

[0070] After the lyocell spinning solution 104 has moved through the jets 122 and further downwards, the long and thin threads of the lyocell spinning solution 104 interact with the coagulation fluid 106.

[0071] During the interaction with the coagulation fluid 106 (for example, water), the solvent concentration of the lyocell spinning solution 104 is reduced, so that the cellulose of the starting material 110 is at least partially coagulated or precipitated as long and thin cellulose fibers 108 (which may still contain residues of solvent and water).

[0072] During or after the initial formation of the individual cellulose fibers 108 from the extruded lyocell spinning solution 104, the cellulose fibers 108 are taken up by the fiber uptake unit 132. The cellulose fibers 108 can be inserted into the Figure 2The cellulose is immersed in the coagulation bath 191 (for example, a water bath, optionally containing a solvent such as NMMO) and can complete its precipitation upon interaction with the liquid of the coagulation bath 191. Depending on the process setting of the coagulation, the cellulose can form cellulose fibers 108 (as shown, whereby the cellulose fibers 108 can be monolithic or integrally fused together ("merging") or can exist as separate cellulose fibers 108) or a film of cellulose can form on the fiber uptake unit 132 (not shown in the diagram). Figure 2 (shown).

[0073] The cellulose fibers 108 are extruded from the spinnerets of the jets 122 and passed through the spinning bath or coagulation bath 191 (containing, for example, water and NMMO in low concentration for precipitation / coagulation). During this process, the cellulose fibers 108 are guided around a deflecting roller 193 within the coagulation bath 191 and, outside the coagulation bath 191, are fed to a take-up galette 195. The take-up galette 195 ensures further transport and stretching of the cellulose fibers 108 to achieve a desired titer. After the take-up galette 195, the fiber bundle of cellulose fibers 108 is washed in a washing unit 180, optionally aerated, and finally cut (not shown).

[0074] Although this in Figure 2Not shown, solvent 116 of the lyocell spinning solution 104, which has been removed from the cellulose fibers 108 during coagulation and subsequent washing in the washing unit 180, can be at least partially recovered or recycled and transferred back into the storage tank 114 in a subsequent cycle.

[0075] During transport along the fiber pickup unit 132, the molded body 102 (here in the form of cellulose fibers 108) can be washed by the washing unit 180, which supplies a washing liquid to remove solvent residues. Afterwards, the molded body 102 can be dried.

[0076] The molded body 102 can also be subjected to post-treatment, see the schematically illustrated post-treatment unit 134. For example, such post-treatment can include hydro-tanglement, needle treatment, impregnation, steam treatment with pressurized steam and / or calendering, etc.

[0077] The fiber receiving unit 132 can feed the shaped body 102 to a winding device 136, where the shaped body 102 can be wound up. The shaped body 102 can then be fed as rolled material to an entity that manufactures products such as wipes or textiles based on the shaped body 102.

[0078] In the Lyocell process according to Figure 2A user can specify the function(s) of a molded body 102 to be produced via an input / output interface 170 of the control unit 140. The input / output interface 170 can have input elements (for example, a keyboard, a touchpad, and / or a control console) through which a user can transmit control commands to the apparatus 100. The input / output interface 170 can also have output elements (for example, an electronic display) through which information about the composition of the processed medium and / or other process parameters can be provided to a user. For example, the user can specify a desired color for the molded body 102 to be produced, a desired degree of elasticity, mechanical robustness, antimicrobial effect, etc.The control unit 140 can then, for example, access a database 152 (e.g., an electronic mass storage device such as a hard drive) where, for example, correlations between the target functions of the molded body 102 to be produced and the residual concentrations of foreign substances remaining in the molded body 102 can be stored in the form of a lookup table. For example, the lookup table can store information on how to pre-sort the starting material 110 according to color and omit or configure the bleaching of the starting material 110 during the manufacturing process to achieve a specific color of the manufactured molded bodies 102 without the need to add separate dye.According to another embodiment, the reference table can contain the information that retaining a certain amount of elastane in the starting material 110, and consequently in the lyocell spinning solution 104, can impart a specific elasticity to the manufactured molded bodies 102. Yet another embodiment can associate retaining a certain amount of polyester from the starting material 110 in the molded body 102 with achieving increased mechanical strength in the molded bodies 102. Retaining a certain amount of zinc oxide from the starting material 110 in the molded bodies 102 can be correlated in the reference table with an antimicrobial effect, which the manufactured molded bodies 102 may then exhibit. In this way, the control unit 140 can use information from the database 152 to determine a user-defined target function for the molded bodies 102, i.e., to adjust process parameters.individual process steps of the manufacturing process according to . Figure 1 and Figure 2 to adapt it so that the desired function is achieved in the molded body 102. In this way, foreign substances can remain in the molded body 102 and be used there to functionalize the molded body 102.

[0079] Further embodiments of the invention are described below. In particular, according to one exemplary embodiment, the functionalization of foreign components from recycled materials can be achieved through selective pulp reuse.

[0080] An exemplary embodiment of the invention relates to the functionalization of non-wood additives as foreign materials, which originate from a recycled material and are selectively incorporated back into a produced fiber. This allows for the utilization of specific properties of these additives and / or the achievement of particular properties in the produced fiber. Exemplary embodiments of the invention thus demonstrate a way to realize or intensify recycling through specific cycles. This can be achieved by foregoing unnecessary or even functionally undesirable excessive purity and / or by making prior use a clear criterion for particularly preferred reuse.The use of recycled cellulose, preferably produced from waste textiles, for the production of artificially produced cellulose fibers without the complete removal of foreign materials is ecologically very advantageous, since complex separation processes during pulp production are eliminated or can be replaced by simpler separation and / or purification processes. By-products from the cellulose-containing raw materials (for example, wood, corn straw, bagasse, cotton), which are conventionally considered undesirable and were therefore eliminated in the manufacturing process, can, according to an exemplary embodiment, remain at least partially in a manufactured molded body 102 and fulfill a specific additional function there.

[0081] A common misconception was that virtually all impurities had to be removed from used textiles through sometimes complex processes in order to recover pure cellulose. Such cleaning methods are costly and often ecologically problematic, so the intended effect of efficient resource recycling is almost reversed.

[0082] When using recycled materials as raw materials for pulp production, only moderate purity of these recyclates must be assumed. Such recyclates are frequently contaminated with materials not typical of wood. Removing or disfunctionalizing these materials is complex and often environmentally damaging. This environmental impact can affect both energy consumption (for example, for ozone generation during bleaching) and process by-products (for example, chemical depletion of certain materials).

[0083] Recycled materials can be used in the production of pulp for use in lyocell processes. During the processing of these recycled materials (textile recycling), various foreign substances are generated as a result of closing the material cycle. These are removed during fiber production to ensure that the technical and physical properties are similar or identical to those of a non-recycled fiber. Normally, such foreign substances (such as foreign polymers, metals, or other chemical compounds) are removed (for example, through chemical reactions, bleaching, mechanical filtration, etc.). Therefore, it is standard practice, particularly for the production of viscose and fibers using the lyocell process, to aim for the complete removal of foreign materials.

[0084] Surprisingly, it was found that by selectively controlling residual concentrations during the depletion process (i.e., the recycling process), advantageous properties can be achieved in the resulting fiber or the produced pulp. This functionalization of residual components from the recyclate, achieved in this way, is described below in exemplary embodiments of the invention.

[0085] In particular, the present inventors have found that by selectively controlling the recycled content in a pulp, desired properties in a specific application of lyocell fiber can be supported, controlled, or otherwise influenced. It has also been shown that the environmental impact resulting from the logistics of a multi-product range (i.e., producing, processing, delivering, etc., different pulps depending on their specific recycled content) is significantly lower than that of completely removing foreign materials from a recycled product.

[0086] For a cellulose material according to an exemplary embodiment of the invention, waste textiles based on cotton, viscose, and / or lyocell cellulose, as well as mixtures thereof and / or with other constituents, can be used. This involves the functionalization of the partial degradation of the chain lengths during use. It is particularly important to note that, for example, virgin cotton, due to its high DP value (where DP stands for the average degree of polymerization, i.e., the number of monomer units per macromolecule), is relatively poorly soluble in NMMO. In contrast, a recycled material with a corresponding cotton content is characterized by the previous production and subsequent use (especially as a result of exposure to UV radiation, heat, water, and mechanical stress) in that the DP value decreases to a range that allows for better solubility in NMMO.Typical numerical values ​​for this shift in the Gaussian mean of the DP values ​​range from up to 3000 (and sometimes even higher) for virgin cotton to a value of less than 2000 mL / g for recycled cotton, preferably less than 1000 mL / g, and particularly preferably less than 800 mL / g. These values ​​refer to the limiting viscosity (which correlates with the degree of polymerization of the cellulose) in units of mL / g. Through optional but advantageous additional measures such as selection, blending, boiling, etc., a limiting viscosity value particularly suitable for the lyocell process can be achieved in the range of 200 mL / g to 700 mL / g.

[0087] In a preferred embodiment, the desired proportions of titanium dioxide (TiO₂) are adjusted from recycled materials. The pulp produced in this way, or a mix composed of different pulps with the desired proportion of TiO₂, can be processed into a lyocell molded body 102. After further processing steps, a resulting staple fiber can thus contain a proportion of TiO₂ as an impurity with a matting function.

[0088] In a further particularly preferred embodiment, residual polymers, for example polyester, from recycled materials are used as adhesion enhancers under the cellulose fibers or as thermoplastic property enhancers within a lyocell molded body 102. Such polymers remain essentially inert until the completion of corresponding procedures in the production process. In particular, this allows for the subsequent stiffening of a fabric by heat (illustratively similar to hot glue) (advantageous, for example, for the production of wrinkle-free shirts, pleats, etc.). A very simple method can thus be provided for the production of fabrics that are intended to have the property of high dimensional stability (for example, wrinkle-free).

[0089] By selectively controlling the proportion of residual polymers (such as polyester from shirt sewing threads), a certain degree of thermoplasticity can be achieved in a lyocell fiber as a molded body 102. This molded body then returns the corresponding proportion of residual polymers from the recycled material to a fiber type via a cellulose material, according to an exemplary embodiment of the invention, through the lyocell process (in the sense of a dedicated material cycle). This fiber type can then be used, for example, to produce a dimensionally stable textile (such as a shirt). Synergistically, molded bodies 102 or products derived from them with improved properties can be obtained (for example, better, i.e., greater, water retention, because the fiber's inherent improved dimensional stability means less finishing agent is needed to produce a wrinkle-free quality).Such a production of a wrinkle-reduced textile product or dimensionally stable nonwoven or fleece, carried out according to an exemplary embodiment of the invention, represents a particularly ecological variant of a specifically controlled material cycle.

[0090] In a further particularly preferred embodiment, recycled textiles dyed with vat dyes (i.e., water-insoluble dyes particularly suitable for dyeing cellulose-based textiles) (for example, denim fabrics) are added to the pulp production process in a targeted concentration and / or selected color composition. The manufacturing process alters the color of dyes such as denim indigo, but also deeply embeds them within a lyocell fiber. The example of denim fabrics illustrates several advantages of this approach. Denim fabrics possess at least one of the following properties:Traditional denim: Twill weave, meaning a diagonal rib and / or dense body. A further distinction is made between warp and weft twill, depending on whether the warp or weft threads predominate on the top. The warp is blue, the weft white. On the loom, denim is woven so that the bluer side is on top. To protect the loom's mechanics, denim is now usually woven with the warp-dominant side (in the case mentioned above, the fabric's top side or the blue side) facing down. This also protects the actual fabric's surface from soiling during weaving. Denim fabrics are traditionally made from cotton fibers. Originally, they were dyed throughout with indigo dyes. However, yarns with variable dyeing are now used for denim fabrics. Denim variations: Denim yarns are now only superficially dyed to create a lighter and more environmentally friendly stonewashed effect (i.e., with less dyeing).

[0091] This can be achieved with less effort (in the sense of less time and energy used).

[0092] A lyocell molded body 102 according to an exemplary embodiment of the invention, which is produced from a cellulose with a defined and selected denim content, has a whiteness value that differs from that of normal cotton fiber and can optionally even be directly color-bearing. Through-dyeing of the entire fiber, as achieved according to such an exemplary embodiment of the invention, allows the fiber produced in this way to be blended with a normal fiber. In particular, the dyeing of the normal fiber can then be controlled such that the dye release for achieving the stonewash effect is carried out in a suitable manner. Due to the residual portion of a fiber produced as a molded body 102 according to an exemplary embodiment of the invention, it can be ensured (since, for example, residual dyes are present throughout) that this stonewash effect does not particularly affect this portion of the fiber.Additional washing by the consumer does not result in any further discoloration.

[0093] Another exemplary embodiment of the invention relating to the functionalization of molded bodies 102 based on foreign substances in recyclates consists of the targeted bleaching of the proportion of old denim dyes. This allows, for example, the conversion of indigo to isatin, which gives denim textiles a typical yellow tint due to age. The use of a pulp produced according to an exemplary embodiment of the invention also makes it possible to reduce the cotton fiber content in a denim product by using molded bodies 102 as a substitute, as described in an exemplary embodiment of the invention. This is advantageous in view of global resource optimization (in particular, reducing the area under cotton cultivation to enable an increase in the area under food cultivation).

[0094] In a further particularly preferred embodiment, recyclates with biocidal properties are used for pulp production. Through suitable recyclate selection and processing, these materials retain their biocidal properties even after the lyocell process. This allows the production of molded bodies 102 and products made from them that provide biocidal functionality (for example, nonwovens for medical and cosmetic products, textiles in medical settings, odor-reducing sportswear, bedding with mite protection, etc.). The purifying effect of such a fiber as a molded body 102, according to an exemplary embodiment of the invention, is advantageous in this context.

[0095] In a further particularly preferred embodiment, recyclates with a substantial proportion of lyocell fibers are used as molded parts 102 in the pulp production process. The use of such a pulp for the lyocell process makes it possible to produce recycled products whose technical properties differ only very slightly from those of a lyocell fiber produced without recyclates. In particular, in this embodiment, the whiteness and strength are highly correlated with those of lyocell fiber without recyclates.

[0096] In a further particularly preferred embodiment, recycled materials from used textiles based on lyocell and / or viscose are used. This makes it possible to achieve a low DP value, which is advantageous for a lyocell process, without additional measures.

[0097] A pulp can be suitable for a lyocell process according to an exemplary embodiment of the invention. Such a pulp can contain a recycled content of more than 3 percent by weight. Furthermore, a non-wood pulp component can be present as an impurity in a corresponding molded body 102, in particular of more than 10 ppm, and more specifically of more than 100 ppm. Advantageously, the aforementioned recycled content can originate from waste textiles that come from the same or comparable applications as the products produced from the pulp and / or can have the same or comparable raw material base as the products and / or intermediate products produced from the pulp. These non-wood components can originate from the recycled material. The recycled materials used can have a DP value of 100 mL / g to 2000 mL / g, preferably 150 mL / g to 1000 mL / g, particularly preferably 200 mL / g to 700 mL / g, each expressed as GVZ.The aforementioned non-wood components may, for example, contain vat dyes (and their decomposition components, for example indigo or isatin), polyester, TiO2, optical brighteners, etc., in amounts greater than 1 ppm (preferably greater than 10 ppm or even greater than 100 ppm).

[0098] A molded body 102 produced according to an exemplary embodiment or a product made therefrom can, for example, be used for one or more of the following applications: a) Pulp with polymer content: this allows the product to be heated to over 130°C, preferably over 150°C, particularly preferably over 180°C during its manufacture or service life. b) Pulp with TiO₂: this allows for applications requiring sun protection and / or opacity and / or privacy. c) Pulp with components or decomposition elements of vat dyes: this allows for the production of denim-like textile products. d) Pulp with recycled content from a lyocell process: this allows for the production of molded bodies 102 and products with lyocell-typical properties. e) Pulp with recycled content containing optical brighteners: this allows for the production of products with a high whiteness value. f) Pulp with biocidal recycled content: this allows for the production of molded bodies 102 or products with a biocidal function.

[0099] According to an exemplary embodiment of the invention, the aforementioned cellulose can be used for a lyocell process and / or a lyocell molded body 102 can be produced from it.

[0100] According to an exemplary embodiment, the recycled content of inorganic materials can exceed 10 ppm, in particular 100 ppm.

[0101] According to an exemplary embodiment, the recycled content of non-cellulose materials can exceed 100 ppm, in particular 1000 ppm.

[0102] According to an exemplary embodiment, non-cellulose organic substances can constitute more than 3 percent by weight of the recycled content and be embedded in the pulp.

[0103] Figure 3Figure 200 shows a cross-section of a cellulose fiber 200 produced using a lyocell process. The cellulose fiber 200 produced using a lyocell process has a smooth, round outer surface 202 and is homogeneously filled with cellulose material, free of macroscopic holes. It can therefore be clearly distinguished by a person skilled in the art from cellulose fibers produced using a viscose process (see reference numeral 204 in Figure 200). Figure 4 ) and cellulose fibers from cotton plants (see reference 206 in Figure 5 ) can be distinguished.

[0104] Figure 4 Figure 1 shows a cross-section of a cellulose fiber 204 produced using a viscose process. The cellulose fiber 204 is cloud-shaped and exhibits a plurality of arc-shaped structures 208 along its outer circumference.

[0105] Figure 5Figure 206 shows a cross-section of a natural cellulose fiber 206 from a cotton plant. The cellulose fiber 206 is kidney-shaped and has a material-free lumen 210 as a fully enclosed cavity inside.

[0106] Based on the significant geometric or structural differences of the fibers according to Figures 3 to 5 Is it possible for a specialist to determine, for example under a microscope, unambiguously whether a cellulose fiber was formed using the lyocell process, the viscose process or naturally in a cotton plant?

[0107] It should also be noted that "having" does not exclude any other elements or steps, and "a" or "an" does not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference numerals in the claims are not to be considered as limitations.

Claims

1. A process for producing a regenerated cellulosic molded body (102), comprising: feeding (52) a starting material (110) comprising cellulose and at least one foreign substance; transferring at least a part of the starting material (110) with at least a part of the at least one foreign substance into a spinning mass which additionally comprises a solvent (116) for dissolving (54) at least a part of the cellulose of the starting material (110) in the solvent (116); extruding (70) the spinning mass to form the molded body (102) and subsequently precipitation (56) in a spinning bath (191), thereby obtaining the molded body (102), wherein the molded body (102) comprises cellulose and at least a part of the at least one foreign substance.

2. Method according to claim 1, wherein the method comprises at most partial removal (58) of at least one of the at least one foreign substance by separating a part of the at least one foreign substance from the cellulose of the starting material (110), in particular before precipitation (56), and further in particular before dissolving (54).

3. Method according to claim 1 or 2, wherein the starting material (110) comprises or consists of a recycled cellulose source (154), in particular being formed wholly or partly from residues from clothing production and / or from used clothing, in particular from a consumer.

4. Method according to any one of claims 1 to 3, wherein the at least one foreign substance comprises at least one from a group consisting of a dye, an optical brightener, a matting agent, in particular titanium dioxide, and an antimicrobial substance, in particular zinc oxide.

5. Method according to any one of claims 1 to 4, wherein the at least one foreign substance comprises elastane, which is also at least partially dissolved during the dissolution (54) of the cellulose.

6. Method according to any one of claims 1 to 5, wherein the at least one foreign substance comprises polyester which is at least partially retained in the starting material (110) when the starting material (110) is at least partially dissolved (54), in particular precipitated (56).

7. Method according to any one of claims 1 to 6, wherein the method comprises at least partial removal (60) of non-cellulosic fibers from the starting material (110) prior to precipitation (56), in particular prior to dissolution (54).

8. Method according to any one of claims 1 to 7, wherein the method comprises at least partial, in particular complete, removal (62) of metals from the starting material (110).

9. Method according to any one of claims 1 to 8, wherein in the method the regenerated cellulosic molded body (102) is produced without carrying out a bleaching procedure.

10. Method according to any one of claims 1 to 9, wherein prior to dissolving (54) the starting material (110) is pre-sorted (64) into several color groups and only pre-sorted starting material (110) of a common color group is dissolved (54).

11. Method according to any one of claims 1 to 10, wherein the at least one foreign substance contained in the molded body (102) has a proportion of at least 0.01 percent by weight, in particular at least 0.1 percent by weight, and further in particular at least 1 percent by weight, based on the total weight of the molded body (102).

12. Method according to any one of claims 1 to 11, wherein the shaped body (102) is one of a group consisting of fibers, films, sponges or spheres.

13. A method according to any one of claims 1 to 12, comprising at least one of the following features: wherein the precipitation (56) is effected by diluting the starting material (110) dissolved in the spinning mass by an aqueous environment in the spinning bath (191), in particular in a water bath, further in particular consisting substantially of water or a mixture of water and solvent (116); wherein the method comprises comminution (66), in particular mechanical comminution, further in particular shredding, of the starting material (110) before dissolving (54) the starting material (110) in the solvent (116); wherein the starting material (110) is at least partially freed from fiber-crosslinking crosslinkers of the starting material (110) before its precipitation (56), in particular before its dissolution (54), in particular by means of an alkaline and / or an acidic pretreatment;wherein the starting material (110) is mixed with another cellulose source (156) before its precipitation (56), in particular before its dissolution (54) in the solvent (116), wherein in particular the other cellulose source (156) comprises at least one material from a group consisting of wood pulp, rag pulp, cotton, cellulose produced by a lyocell process and cellulose produced by a viscose process; wherein the process comprises a post-processing (74) of the precipitated solid (102); wherein the dissolution (54) of the starting material (110) is carried out by means of a direct dissolution process and / or by means of tertiary amine oxides, in particular N-methylmorpholine N-oxide, as solvent (116); wherein the method comprises adjusting a desired or predetermined residual concentration of the at least one foreign substance in the molded body (102) to achieve a function of the at least one foreign substance in the molded body (102);wherein the process is carried out such that, based on a control command, a quantity of the at least one foreign substance remaining in the manufactured molded body (102) is user-defined and, in particular, is set higher than a minimum value of the respective foreign substance achievable through process engineering; wherein the cellulose and the at least one foreign substance of the starting material (110) are present in a common solid composite during feeding (52), in particular during transfer, in particular in at least one of a group consisting of a textile fabric, a fiber composite and a molded body composite; wherein the process comprises further processing of manufactured molded bodies (102) into a product, in particular into a textile fabric.

14. Use of a starting material (110) comprising cellulose and at least one foreign substance for the production of a regenerated cellulosic molded body (102) by means of the Lyocell process, wherein the molded body (102) contains cellulose and at least part of the at least one foreign substance.

15. Use according to claim 14, comprising at least one of the following features: wherein the at least one foreign material is used in the molded body (102) to provide the molded body (102) with a function of the at least one foreign material; wherein elastane is used as the foreign material to impart elasticity to the manufactured molded body (102); wherein polyester is used as the foreign material to impart thermoplastic deformability and / or increased mechanical stability to the molded body (102).