Reuse of Lvocell cellulose for Lvocell processes

The invention relates to a method for producing a molded body comprising cellulose and to a use.

Viscose fibers are chemical fibers or regenerated fibers that are produced using a wet spinning process called viscose. The starting raw material of the viscose process is cellulose, which is provided on the basis of wood. The high-purity cellulose in the form of chemical pulp is obtained from this raw material, wood. In

In successive process stages, the pulp is first treated with caustic soda, which forms alkali cellulose. In a subsequent

The reaction of this alkali cellulose with carbon disulfide forms cellulose xanthate. From this, the viscose spinning solution is generated by adding more sodium hydroxide solution, which is then fed into a spinneret through the holes of shower-like spinnerets

Spinning bath is pumped. A viscose filament is created there by coagulation per spinneret hole. The viscose filaments produced in this way are then cut into viscose staple fibers.

Lyocell is the name of a type of regenerated fiber containing cellulose that is produced using a direct solvent process. The cellulose is extracted from the raw material wood for the Lyocell process. The pulp obtained in this way can then be dissolved in N-methylmorpholine-N-oxide (NMMO), a solvent, by removing water without chemical modification, filtered and

are then pressed through spinnerets. The filaments formed in this way are precipitated after passing through an air gap in a bath with aqueous NMMO solution and then cut into staple fibers.

The raw material wood is conventionally used for both the lyocell process and the viscose process.

It is an object of the present invention to produce cellulose products in a resource-saving and sustainable manner.

This task is carried out by the subjects according to the independent

Patent claims solved. Preferred refinements result from the dependent claims.

According to one embodiment of the present invention, a method for producing a molded body containing cellulose is created, wherein in the method a starting material containing cellulose produced by means of a Lyocell method is supplied, which by means of (in particular direct) dissolution (in particular by removal of water without chemical modification) a Cellulose source is produced in a solvent and by subsequent precipitation of the cellulose by diluting the dissolved cellulose source, the starting material containing cellulose (in particular present in a solid phase,For example, as a solid body or in the form of solid particles) is dissolved (in particular directly) in a solvent (in particular by removing water without chemical modification) and subsequently at least part of the cellulose is precipitated by diluting the dissolved starting material, whereby the shaped body (for example a fleece or nonwoven) is obtained.

According to another exemplary embodiment of the present invention, a method for producing a regenerated cellulose molded body is created, the method comprising supplying a starting material comprising cellulose produced by means of a Lyocell process, which is produced by dissolving a cellulose source in a solvent for producing a spinning mass by means of Extruding the spinning mass and is produced by subsequent precipitation in a spinning bath, dissolving the cellulose-containing starting material in a further solvent to produce a further spinning mass, and extruding and subsequent precipitation of the further spinning mass in a further spinning bath, whereby the shaped body is obtained.

According to another exemplary embodiment, a starting material comprising cellulose produced by means of a first Lyocell process is used for producing a molded body comprising cellulose by treating the

Starting material used by means of a second Lyocell process.

In the context of this application, the term “cellulose” can be understood in particular as an organic compound which is a component of plant cell walls or which can be produced synthetically. Cellulose is a

Polysaccharide (i.e. a polysaccharide). Cellulose is unbranched and typically has several hundred to tens of thousands of ß-D-glucose molecules (ß-1,4-glycosidic bond) or cellobiose units. Plants build cellulose fibers from cellulose molecules in a controlled manner. With a

technical process can form cellulose molecules

Regenerated fibers are stored together, for example as tear-resistant fibers.

In the context of this application, the term "molding"

in particular a two- or three-dimensional geometric body can be understood which is a result of a method for producing or recovering cellulose. In particular, a shaped body can be understood to mean a two- or three-dimensional object which has or consists of cellulose and is produced from dissolved cellulose. Shaped bodies can in particular be Lyocell shaped bodies, viscose shaped bodies or Modal shaped bodies. Typical molded bodies are filaments, fibers, sponges and / or films. In principle, all types of cellulose moldings are suitable for

Embodiments of the invention. Both as fibers

Endless filaments as well as cut staple fibers with conventional

Dimensions (for example, 38 mm length) and short fibers to be understood. Both methods are used for the production of fibers

Extraction devices after one or more extrusion nozzles as well as other processes, such as in particular melt-blowing processes, are possible. As an alternative to fibers, a cellulose-containing film can also be produced as the shaped body, ie a flat and essentially homogeneous film with or from cellulose. Foils can in particular be produced by setting the process parameters of a Lyocell process, at least in part, to initiate coagulation only after the filaments have hit a receiving surface. Films can be understood to mean flat cellulose molded bodies, the thickness of these films being adjustable (for example by selecting a number of serially arranged nozzle bars). Other embodiments of a molded body are a woven fabric and a fleece made of cellulose filaments or

Cellulose filaments ("melt blown"). Here, under a fabric

in particular a textile fabric made of at least two (preferably at right angles or almost at right angles) crossed thread systems (or

Fiber systems) are understood, with threads (or fibers) in the longitudinal direction as warp threads and threads (or fibers) in the transverse direction as weft threads

can be designated. A fleece or nonwoven can be referred to as a disordered structure (in particular in a random layer) made of filaments or fibers or cut yarns of limited length, which form a

Fiber layer or a fiber pile joined together and (in particular

frictionally) are connected to each other. A shaped body can also be created in the shape of a sphere. Particles containing cellulose, such as, in particular, beads (i.e. a granulate or spheres) or flakes, which can be further processed in this form, can also be provided as shaped bodies. Possible cellulose molded bodies are therefore also particulate structures such as granules, spherical powders or fibrids. A shaped body is preferably shaped by extrusion of a cellulose-containing spinning solution through an extrusion nozzle, since in this way large quantities of cellulose shaped bodies can be produced with a very uniform shape. Another possible cellulose molded body is a sponge or, more generally, a porous molded body.

Composite materials are used.

In the context of this application, the term “cellulose source” can be understood in particular as a medium (in particular a solid medium) which provides the cellulose material used for this purpose as a basis for producing a molded body containing cellulose during a corresponding production process. An example is wood or wood pulp.

In the context of this application, the term “Lyocell process” can be understood in particular as a process for producing cellulose by a direct solvent process. For the Lyocell process, the cellulose can be obtained from a starting material which contains this cellulose. The starting material can in the Lyocell process in a suitable solvent (in particular comprising tertiary amine oxides such as N-methylmorpholine-N-oxide (NMMO) and / or ionic liquids, ie low-melting salts which are built up from cations and anions) The solution obtained, which can also be referred to as dope or spinning solution, can be used in the Lyocell process

then pressed through one or more spinnerets. Filaments formed as a result can during and / or after their free or

controlled falling through an air gap in a water-containing bath

(in particular in a bath with aqueous NMMO solution) and / or the air humidity in the air gap can be precipitated.

In the context of this application, the term “viscose process” can in particular include a process for producing cellulose according to a

Wet spinning processes are understood. The cellulose can be used for that

Viscose process from a raw material (especially wood or a

Wood pulp) containing this cellulose. In

successive process stages can be used in the viscose process

The starting material must first be treated with a base (for example with sodium hydroxide solution), whereby alkali cellulose is formed. When this alkali cellulose is then reacted with carbon disulfide, cellulose xanthate is formed. From this, a viscose spinning solution can be generated by further adding a base (in particular sodium hydroxide solution), which by one or more

Spinnerets can be pressed. In a spinning bath arise through

Coagulation of viscose filaments.

In the context of this application, the term “residues from a

Clothing manufacture "in particular rejects and / or offcuts

Cellulose comprising or consisting of textile or yarn are understood, these residues during a process for the production of

Clothing. In the manufacture of clothing, for example, a cellulose-containing textile is produced as the starting material, from which flat parts (for example in the form of a T-shirt half) are cut out. What remains are residues which, according to an exemplary embodiment, can be fed back to a method for producing a molded body comprising cellulose. Garment-making scraps can therefore be a cellulose-based or cellulose-based raw material that can be used to recover cellulose before a consumer has used the scraps as clothing or in some other way. Remnants from a clothing production can in particular be formed from essentially pure cellulose, in particular without separate and non-cellulose

foreign bodies (such as buttons, textile prints or seams).

In the context of this registration, the term "old clothes"

in particular items of clothing containing cellulose are to be understood which, when recovering at least part of the cellulose, have already been taken from a

Consumers have been used (especially worn). Used clothing can therefore be a cellulose-containing raw material, which can (but does not have to) contain significant amounts of foreign substances and can be used to recover cellulose after a

Consumer who has used old clothes as clothing or in any other way. Old clothes can in particular be formed from a mixture of cellulose and one or more foreign substances, in particular containing synthetic plastic (such as polyester and / or elastane) and / or separate foreign bodies not containing cellulose (such as, for example Buttons, textile prints or seams). Polyesters are understood to mean, in particular, polymers with ester functions (R - [- C0-0 -] - R) in their main chain. Polyesters include polycarbonates and polyethylene terephthalate. Elastane is particularly elastic

Understood chemical fiber with high elasticity. A block copolymer on which elastane is based can contain a mass fraction of at least 85% polyurethane.

According to an exemplary embodiment of the invention, can

Cellulose molded bodies can be produced at least partially on the basis of a starting material produced by means of a Lyocell process (for example Lyocell textile scraps and / or Lyocell old textiles), which can be done with a quick and simple production process and in a resource-saving and sustainable manner. These advantages are based in particular on the fact that lyocell cellulose can be fed to and subjected to a further lyocell process in a particularly unproblematic manner. Since the Lyocell process is a direct dissolving process, in which cellulose can be fed directly to a dope and is readily dissolved there, there is no need for complex chemical pretreatment of the starting material. On the

The manner described can advantageously contain a lyocell cellulose

Starting material for a recovery or recycling of this cellulose are introduced into a new Lyocell process. Since, surprisingly, the cellulose is not subjected to any significant degradation during the Lyocell process, repeated iterative recycling of Lyocell cellulose to a new Lyocell process is possible without any significant deterioration in the quality of the cellulose of the molded bodies produced. It has been found that in several successive Lyocell processes with the respective reuse of Lyocell cellulose obtained in a previous iteration, the limiting viscosity number is only very slightly reduced. This is almost negligible,

successive viscose processes with the respective reuse of previously obtained viscose. There is a much faster and stronger one

Reduction in the intrinsic viscosity number than with a sequence of several Lyocell processes. A Lyocell-from-Lyocell architecture according to the exemplary embodiment is therefore even more advantageous than a viscose-from-viscose architecture.

Additional exemplary embodiments of the method and the use are described below.

According to one embodiment, the diluted can be diluted

Cellulose source can be brought about by an aqueous medium, in particular having controllable air humidity and / or a water bath, further in particular essentially consisting of water or a mixture of water and solvent (in particular NMMO). In a corresponding manner, the dissolved starting material can be diluted by an aqueous medium, in particular having controllable humidity and / or a water bath, further in particular consisting essentially of water or a mixture of water and solvent (in particular NMMO). In the first Lyocell process or in the second Lyocell process, the water (in particular controllable air humidity in combination with a liquid bath with water and optionally a

Solvent) the concentration of the solvent that caused the cellulose to dissolve is reduced so much that the dilute solution obtained falls below the solubility limit of cellulose and the cellulose thereby precipitates or precipitates. The coagulation medium (ie in particular the humidity or the water bath) can be essentially pure water or can be provided with a solvent.

According to one embodiment, in the method, the molded body can after completion of its production and preferably after use

Molded body or a product made therefrom for an intended purpose (for example as a piece of clothing) can be dissolved again in a solvent and subsequently at least part of the cellulose is precipitated by diluting the dissolved molded body, whereby - by performing a third Lyocell process - another molded body is obtained. In other words, according to the second Lyocell process, at least one further Lyocell process based on the product obtained from the second Lyocell process can be carried out as the starting material for this third Lyocell process. So at least three, in particular at least four or even more Lyocell processes can be serially strung together in order to reclaim cellulose again and again. That this is possible is based on the only very slight degradation of the cellulose during the execution of a Lyocell process, this degradation, for example, being significantly less than with several viscose processes carried out in series. This means that a multi-stage can also be used for large-scale technical applications

Recovery of lyocell cellulose are made possible, which leads to a particularly efficient and environmentally friendly use of resources. For example, textiles (ie linear, flat or three-dimensional structures made in particular on the basis of cellulose) that contain lyocell cellulose in pure form or as a mixed fabric can also be recycled more than twice by performing a new lyocell process. For example, in a Lyocell process, starting from an initial intrinsic viscosity (which begins with the

Degree of polymerisation of the cellulose correlates) from 400 ml / g to only a slight reduction to about 390 ml / g. In comparison with this, in a viscose process, a reduction of the parameter mentioned can take place in successive iterations from, for example, initially 550 ml / g to 240 ml / g and in a next run to 220 ml / g. This predestines the Lyocell process in a special way for a resource-saving and sustainable multiple successive recovery of what is produced with it

Cellulosic material.

According to one exemplary embodiment, the method can comprise comminuting, in particular mechanical comminution, further in particular shredding, of the starting material before dissolving the starting material in the solvent. For example, comminution can reduce the size of the starting material to the size of fibers. In particular, a starting material prepared in this way can also be converted directly into solution without chemical pretreatment in order to produce a viscous spinning mass.

According to an exemplary embodiment, the method can be a solving the

Raw material in the solvent without chemical pretreatment,

especially without chemical cleaning and / or without setting the

Viscosity. This is a particularly efficient way

Lyocell cellulose can be recovered using another Lyocell process.

According to another exemplary embodiment, the method can include at least partial cleaning, in particular chemical cleaning, of the starting material before the starting material is dissolved in the solvent. Should

Cellulose can be recycled in a particularly pure form, the starting material can be cleaned in an upstream, optional cleaning step.

For example, according to an exemplary embodiment, the cleaning can include at least partial removal of dyes (in particular by means of bleaching the starting material) from the starting material before the starting material is dissolved in the solvent. In this way, for example, pure white or at least light-colored cellulose material from the

Raw material can be recovered, for example when intensely colored denim jeans material is to be recycled. Alternatively, however, it is also possible to use textiles containing lyocell to be recycled without prior use

Discoloration can be removed directly, if necessary after mechanical crushing.

According to one exemplary embodiment, the starting material can be at least partially freed from crosslinkers, which crosslink the fibers of the starting material, before it is precipitated (preferably even before it is dissolved). This can be done, for example, by means of an alkaline and / or an acidic pretreatment, in particular depending on the type of crosslinker present. A lyocell fiber is a fibrillating fiber that can be cross-linked with molecules. A corresponding crosslinker can interfere as it can reduce the solubility of Lyocell cellulose in Lyocell solvents. The at least partial removal of the

Crosslinker by means of pretreatment (for example by performing

an alkaline step and / or an acidic step) with partial or complete dissolution of the undesired crosslinking can increase the purity of the cellulose obtained.

According to one exemplary embodiment, the starting material can be wholly or partially remnants from clothing production and / or old clothes (for example

Mixed textiles). In other words, textiles, in particular leftovers from clothing manufacture and / or old clothes, can be used as at least part of the starting material. That is particularly preferred

Use of leftovers from clothing production, since such offcuts or rejects often have a very high cellulose content and thus a high degree of purity. In particular, such a pre-consumer textile can be free from foreign bodies such as buttons, seams or textile printing. For example, residues from clothing production can essentially comprise woven (and optionally dyed) cellulose, so that such residues can, if necessary, also be converted directly into solution in order to be converted therefrom by means of the lyocell

Process to recover cellulose. In the case of old clothes or post-consumer textiles, larger foreign objects such as buttons, prints and seams can be removed during or after mechanical shredding. Other foreign matter from the leftovers or old clothes, such as paints and synthetic plastics (such as polyester and elastane), may be removed before loosening one

corresponding starting material for forming the dope or the spinning solution can be completely or partially removed, but can also remain completely or partially in the spinning solution.

According to one embodiment, the starting material can be mixed with at least one other starting material comprising cellulose before it is precipitated (in particular before it is dissolved in the solvent). For example, the other starting material can have at least one material from a group consisting of wood pulp, rag pulp (in particular pulp made from scraps of fabric such as linen, rag, etc.), textiles, clothing, cotton (i.e. cellulose from a cotton plant) and produced by means of a viscose process Cellulose. It is therefore also possible to provide only part of the starting material for the subsequent Lyocell process in the form of Lyocell cellulose from a preceding Lyocell process. The starting material can also be an inhomogeneous mixed fabric. The rest of the raw material,

Availability can be replenished by one or more other sources of cellulose. As a result, the large-scale use of the Lyocell-from-Lyocell process is not impaired by any temporary shortages of Lyocell cellulose. Rather, it is possible to compensate or compensate for any shortfalls in lyocell cellulose with other cellulose sources. Preferred because it is particularly uncomplicated in terms of process technology, but the creation of the

The starting material can only be made of Lyocell cellulose.

According to one embodiment, the dissolution of the starting material and / or the dissolution of the cellulose source can take place by means of a direct dissolution process.

In such a direct dissolution process, the cellulose is clearly physically dissolved in the respective solvent. Preferably here as

Solvent tertiary amine oxides are used, particularly preferably N-methylmorpholine-N-oxide (NMMO).

According to one embodiment, the method can include post-processing of the precipitated cellulose in order to adjust the properties of the shaped body. Such an optional post-processing can for example be a

Have drying, impregnation and / or reshaping of the cellulose filaments obtained. Corresponding post-processing makes it possible, at the end of the Lyocell-from-Lyocell process, to use the

Complete molding production.

According to one embodiment, fibers of the starting material and / or fibers of the molded body can have a smooth, round outer surface. As shown in FIG. 3, extracted by means of the Lyocell process stand out

Cellulose fibers are distinguished by such a shape and therefore stand out from other fiber shapes such as those found in natural cotton or obtained by means of a viscose process.

The moldings produced according to the invention can, for example,

Packaging material, fiber material, textile composites, fiber composites, nonwovens, needle felts, upholstery wadding, fabrics, knitted fabrics, as home textiles, such as bed linen, as items of clothing, as fillers, flocking material,

Hospital textiles, such as pads, diapers or mattresses, can be used as material for thermal blankets, shoe insoles and wound dressings.

Embodiments of the invention can be in the most varied

technical fields as well as in medicine and in cosmetics and wellness. In medicine, for example, materials for

Wound treatment and wound healing can be composed of a carrier, which determines the mechanical properties, and a biocompatible coating material, which is particularly compatible with the skin and with the surface of the wound. Numerous other uses are possible.

In the following, exemplary embodiments of the present invention are described in detail with reference to the following figures.

FIG. 1 shows a flow diagram of a method for producing a shaped body comprising cellulose according to an exemplary embodiment of the invention.

Figure 2 shows an apparatus for producing a cellulose containing

Shaped body by means of a Lyocell process based on a starting material produced by means of a Lyocell process according to an exemplary embodiment of the invention.

FIG. 3 shows a cellulose fiber produced by means of a Lyocell process.

FIG. 4 shows a cellulose fiber produced by means of a viscose process.

FIG. 5 shows a natural cellulose fiber from a cotton plant.

Identical or similar components in different figures are provided with the same reference numbers.

Before exemplary exemplary embodiments are described with reference to the figures, some basic considerations should be summarized, based on which exemplary exemplary embodiments of the invention have been derived.

According to an exemplary embodiment of the invention, lyocell recycling materials are used for the production of lyocell fibers. The main difference to other cellulose-containing raw materials is that Lyocell can be added back to the dope directly (ie without chemical pretreatment, preferably after shredding). The cellulose then goes back into solution in a suitable solvent (especially NMMO). This is only possible because the Lyocell process is a direct dissolution process and does not contain any significant degradation of the cellulose (DP degradation, where DP stands for the average degree of polymerization, ie the number of

Monomer units per macromolecule) takes place.

So once a pulp has been conditioned in a Lyocell process (especially in the sense of: the viscosity has been

set accordingly) that it is suitable for the Lyocell process, the end product resulting from the process (Lyocell fibers or textiles or other application products made from them) can be used in a closed cycle as often as desired (with the average

The degree of polymerization decreases slightly over time) can be reused.

Lyocell recycling materials can therefore take the place of conventional pulp.

Measures can preferably be taken during the procedure

To keep impurities in the starting material low or to separate them beforehand (to avoid clogging of a filter of a Lyocell apparatus), to keep foreign materials low in mixtures or to separate them beforehand (to achieve a high degree of purity of the recycled Lyocell cellulose), and / or to keep larger particles small or to separate them beforehand. Preferred starting materials are according to an exemplary one

Exemplary embodiment waste from lyocell fiber production and pre-consumer waste, in particular with a high degree of purity.

According to an exemplary embodiment of the invention, processing (for example cleaning, adjusting the viscosity) after the feed of the starting material can advantageously be dispensed with. Clearly, with a method according to an exemplary embodiment, lyocell cellulose can be processed again directly into lyocell cellulose. In other words, materials produced by means of a Lyocell process can be used as raw material for a subsequent further Lyocell process.

According to a preferred embodiment of the invention, recyclates (in particular recycled plastics from post-consumer waste) with a substantial proportion of Lyocell fibers can be used in the production of cellulose. By using such a pulp for the

In the Lyocell process, recycled products are possible that differ only slightly or even minimally or not at all in their technical properties from a Lyocell fiber that was produced without recycled material. In particular, in this embodiment the whiteness and strength values ​​are highly correlated with the lyocell fiber without recyclates.

For example, at least 3 percent by weight, in particular at least 10 percent by weight, further in particular at least 50 percent by weight, Lyocell fibers based on the total weight of the starting material

Starting material are provided.

FIG. 1 shows a flow chart 50 of a method for producing a molded body 102 comprising cellulose (see FIG. 2) according to an exemplary embodiment of the invention.

First of all, it is described with reference to FIG. 1 how a starting material 110 (compare FIG. 2) is produced, which after use as a product (see block 60) is recycled by means of a Lyocell process.

To produce such a cellulose-containing starting material 110, a cellulose source 48 is first used, ie a medium containing cellulose. This can be wood pulp, for example. By dissolving 52 the cellulose source 48 in a suitable solvent (compare, for example, reference numeral 116 in FIG. 2, for example tertiary amine oxides such as, for example, N-methylmorpholine-N-oxide (NMMO); however, a different solvent can also be used for the cellulose source 48 e.g. ionic liquids) a Lyocell spinning solution or spinning mass can be generated, ie the cellulose can be converted into solution.

The Lyocell spinning solution or spinning mass produced in this way can then be passed through one or more filters (in which, for example, foreign substances

can be retained) and then pressed through one or more spinnerets of a Lyocell apparatus, whereby filaments containing cellulose with a consistency that are still tough as honey are obtained by means of extrusion (see block 54).

By diluting the dissolved cellulose source 48, ie the Lyocell spinning solution after passing through the spinnerets through a preferably water-containing or even water-based coagulation medium (in particular a spinning bath, such as the spinning bath shown in FIG. 2 with reference number 191 or another spinning bath), a Coagulation, precipitation or precipitation 56 of the cellulose from the Lyocell spinning solution can be triggered. In this way, cellulose, for example in the form of fibers, can be produced in a solid phase (ie now in the form of a solid).

As illustrated by block 58, the cellulose obtained or extracted in this way can be subjected to an optional aftertreatment, for example drying or a change in the geometrical appearance of the cellulose (for example by cutting into staple fibers).

In other words, as shown by blocks 48, 52, 54, 56 and 58, the method described can include producing the cellulose

Starting material 110 by dissolving 52 the cellulose source 48 in the

Solvent and subsequent precipitation 56 of the cellulose by diluting the dissolved cellulose source 48 accomplish. In other words, the starting material 110 can be produced by means of a lyocell process shown in blocks 48, 52, 54, 56 and 58.

The starting material 110 can also be further processed, for example by producing clothing based on the extracted cellulose. The cellulose can be processed further into a textile fabric, for example, in particular using further constituents (for example

synthetic plastics such as polyester and elastane). Parts of the textile fabric can be cut out and additional non-cellulose bodies such as buttons and seams can be processed into a piece of clothing (for example a T-shirt).

As shown by block 60, a raw material 110 produced in this way can be used by a consumer, for example as an item of clothing.

If the consumer discards the item of clothing, it can be used as a post-consumer starting material 110 for a subsequent, further Lyocell process, which is described in more detail below. As an alternative or in addition, it is also possible to use a pre-consumer starting material 110 comprising lyocell cellulose for a subsequent further lyocell process, for example scraps from clothing manufacture.

Furthermore, it is described how molded bodies 102 can be produced from Lyocell cellulose according to an exemplary embodiment of the invention on the basis of the starting material 110 containing at least some lyocell cellulose. For this purpose, the starting material 110 is fed to an apparatus 100 (see FIG. 2) for carrying out a Lyocell process, compare reference numeral 78.

There the starting material 110 can first be mechanically comminuted 62 by shredding. As a result, large non-cellulosic contaminants in particular can be removed from the starting material 110, for example buttons, seams and prints on old clothes that are used to produce the starting material 110

have been used at least in part. The mechanical comminution 62 can, for example, cut the starting material 110 into individual fibers.

It is also possible (see block 64) to have the lyocell cellulose

Use starting material 110 together with other cellulose-containing materials for the subsequent Lyocell process. Thus the

Starting material 110 can be mixed with another starting material comprising cellulose, see block 64. For example, starting material 110 can alternatively or additionally also contain residues from a clothing production. Furthermore, it is optionally possible to add another cellulose-containing material, such as wood pulp, to the starting material. It is therefore possible to mix the starting material 110 obtained according to the first and above-described Lyocell method with a further non-Lyocell starting material comprising cellulose. The latter can for example

Rag cellulose from textiles, cotton from a cotton plant, cellulose obtained from a viscose process and / or Cotton Lint (ie considerably shorter compared to the approximately 38 mm long Cotton Lint, for example

Cotton strands as they grow on the seed of a cotton plant). The proportion of cellulose obtained by means of the Lyocell process in the starting material 110 can be, for example, between 3 percent by weight and 100 percent by weight, in particular between 10 percent by weight and 80 percent

Weight percent. It is particularly preferred if this proportion is 100

Weight percent (the person skilled in the art is familiar with the fact that a small proportion of foreign matter can always be present).

Immediately after mechanical comminution 62 or immediately after mixing 64, the (pure or mixed) starting material 110 can be dissolved directly in a further solvent 116 (for example tertiary amine oxides such as N-methylmorpholine-N-oxide (NMMO)) advantageously take place without chemical pretreatment, whereby a spinning mass is obtained. More accurate

stated, the mechanically comminuted (and optionally mixed) starting material 110 can be converted directly into solution, in particular without chemical cleaning and without adjusting the viscosity. In this way, the manufacturing or. Recycling process exceptionally easy and quick as well

be carried out in an environmentally friendly manner.

Alternatively, the method can include an optional chemical cleaning 66 of the starting material 110 after the mechanical comminution 62 (or after the mixing 64) and before the dissolving 68. Such an optional cleaning 66 can, for example, comprise at least partial removal of colorants by bleaching. This makes it possible to use the starting material 110 before

subsequent dissolving 68 of the starting material 110 in solvent 116 to wholly or partially decolorize, for example to produce white or gray moldings 102. As an alternative or in addition, it is also possible that, in the context of the optional chemical cleaning 66, the starting material 110 (before or after its dissolution 68) is at least partially freed of crosslinkers that cross-link fibers of the starting material 110. In applications where such

If crosslinkers are present between the fibers of the starting material 110, the starting material 110 can be completely or partially freed from these crosslinkers, for example by means of an alkaline or an acidic pretreatment. This additionally improves the solubility of the starting material 110.

After dissolving 68 the starting material 110 in solvent (preferably NMMO), the Lyocell spinning solution or spinning mass obtained can be pressed through one or more spinning nozzles, whereby threads or filaments with a honey-viscous viscosity are formed by means of extrusion (see block 70, which relates to this spinning) .

During and / or after these threads or filaments fall, they are brought into operative connection with an aqueous medium and thereby diluted. The concentration of the solvent 116 of the threads or filaments is thereby reduced, for example in an aqueous liquid bath as a spinning 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, fall or coagulate, see reference numeral 72. This gives the molded body 102 or a preform for a staple fiber.

The loosening 68, spinning 70 and subsequent precipitation 72 by means of a Lyocell process is therefore carried out based on a starting material 110, which in turn is produced by means of a preceding Lyocell process

Comprises or consists of cellulosic material. That can be illustrated

The manufacturing processes described are therefore referred to as lyocell-with-lyocell processes. In other words, a starting material 110 comprising cellulose produced by means of a first Lyocell process can be used for

Production of a molded body 102 comprising cellulose by treating the starting material 110 by means of a second Lyocell process can be used.

Furthermore, the method can include post-processing 74 of the precipitated Lyocell cellulose in order to influence the properties of the molded body 102. Such post-processing can include, for example, drying, impregnating and / or reshaping the filaments obtained into the final shaped body 102. For example, the molded body 102 can be processed into fibers, a film, a woven fabric, a fleece, a ball, a porous sponge or beads by the production method described and then fed to a further use (cf. reference numeral 76).

Advantageously, after the molded body 102 has been used, its Lyocell cellulose can be recovered again by a further Lyocell process

is carried out in accordance with the method steps between reference symbols 78 and 74 (see block 80). This multiple repeatability of lyocell recycling by means of repeated lyocell process steps is made possible by the knowledge that the degradation or DP reduction of lyocell cellulose through repeated repetitions of lyocell processes is surprisingly small.

FIG. 2 shows an apparatus 100 for producing a molded body 102 comprising cellulose by means of a Lyocell process based on a starting material 110 produced by means of a preceding Lyocell process according to an exemplary embodiment of the invention which was described with reference to FIG.

FIG. 2 therefore shows an apparatus 100 according to an example

Embodiment of the invention for producing a molded body 102 comprising cellulose, which can be produced, for example, in the form of a nonwoven, as fiber, film, ball, textile fabric, sponge or in the form of beads or flakes. According to FIG. 2, the molded body 102 is produced directly from a spinning solution 104. The latter is converted into cellulose fibers 108 by means of a coagulation fluid 106 (in particular from air humidity) and / or a coagulation bath 191 (for example a water bath that optionally has tertiary amine oxides such as N-methylmorpholine-N-oxide (NMMO))

Molded body 102 converted. A Lyocell process can be carried out by means of the apparatus 100. In this way, for example, essentially endless filaments or fibers 108 or mixtures of essentially endless filaments and fibers 108 of discrete length can be produced as molded body 102. A plurality of nozzles, each having one or more openings 126 (which may also be referred to as spinning holes), are provided for ejecting Lyocell dope 104.

As can be seen in FIG. 2, a cellulose-based starting material 110 can be fed to a storage tank 114 via a metering device 113.

According to one exemplary embodiment, water can be introduced into the cellulose-based starting material 110 by a solvent 116 (in particular NMMO) described in more detail below. It can also be cellulose based

Starting material 110 itself already contain a certain residual moisture (dry cellulose, for example, often has a residual moisture of 5 percent by weight to 8 percent by weight). In particular, according to the described

Exemplary embodiment, the starting material 110 can be added directly to a mixture of water and solvent 116 without pre-moistening. An optional water container 112 shown in FIG. 2 can then be omitted.

According to an alternative embodiment, the cellulose-containing starting material 110 can additionally be moistened in order to thereby provide moist cellulose. For this purpose, water from an optional

Water tank 112 can be fed to storage tank 114 via metering device 113. Therefore, the metering device 113, controlled by means of a control device 140, can supply adjustable relative amounts of water and starting material 110 to the storage tank 114.

A suitable solvent 116, preferably tertiary amine oxides such as N-methylmorpholine-N-oxide (NMMO), or an aqueous mixture of the solvent 116, for example a 76% strength solution of NMMO in water, is contained in a solvent container. The concentration of the

Solvent 116 can be adjusted in a concentrating device 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. Also the

Mixing unit 119 can be controlled by means of control unit 140. As a result, the starting material 110 comprising cellulose is concentrated in the

Solvent 116 dissolved in a dissolving device 120 with adjustable relative amounts, whereby the Lyocell spinning solution 104 is obtained. The relative concentration ranges (also referred to as spinning window) of the components starting material 110, water and solvent 116 in the spinning solution 104 for the production of cellulosic regenerated molded bodies the Lyocell process can, as known to a person skilled in the art, be suitably adjusted.

The lyocell dope 104 is fed to a fiber generation device 124 (which may be formed with a number of spin bars or jets 122).

As the lyocell dope 104 is passed through the openings 126 of the jets 122, it is divided into a plurality of parallel strands of lyocell dope 104. The process control described transforms the Lyocell spinning solution 104 into increasingly long and thin threads, the properties of which can be adjusted by appropriate setting of the process conditions, controlled by the control unit 140. Optionally, a flow of gas can move the lyocell dope 104 on its way from the openings 126 to one

Accelerate fiber take-up unit 132.

After the Lyocell spin solution 104 has moved through the jets 122 and down, the long and thin threads of the Lyocell spin solution 104 interact with the coagulation fluid 106.

When interacting 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 as long and thin cellulose fibers 108 (which can still contain residues of solvent and water) coagulates or fails.

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 on the fiber take-up unit 132. The cellulose fibers 108 can dip into the coagulation bath 191 shown in FIG. 2 (for example a water bath, optionally containing a solvent such as NMMO) and can complete their precipitation when interacting with the liquid in the coagulation bath 191. Depending on the process setting of the coagulation, the cellulose can form cellulose fibers 108 (as shown, wherein the cellulose fibers 108 can be one material or integrally fused with one another (“merging”) or can be present as separate cellulose fibers 108) or a film can form on the fiber receiving unit 132 or.

The cellulose fibers 108 are thus extruded from the spinnerets of the jets 122 and guided through the spinning bath or coagulation bath 191 (containing, for example, water and NMMO in a low concentration for precipitation / coagulation), while the cellulose fibers 108 are guided around a respective deflection roller 193 im Coagulation bath 191 and fed outside of the coagulation bath 191 to a godet 195. The take-off godet 195 ensures that the cellulose fibers 108 are transported further and further drawn in order to achieve a desired titer. After the godet 195, the fiber bundle is from the

Cellulose fibers 108 washed in a washing unit 180, optionally finished and finally cut (not shown).

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

During the transport along the fiber receiving unit 132, the

Shaped bodies 102 (here in the form of cellulose fibers 108) are washed by means of the washing unit 180, in that the latter supplies a washing liquid to remove solvent residues. The shaped body 102 can then be dried.

The molded body 102 can also be subjected to an aftertreatment, see the aftertreatment unit 134 shown schematically. For example, such an aftertreatment can be a hydroentangling,

Needle treatment, impregnation, steam treatment with a steam supplied under pressure and / or calendering, etc. have.

The fiber receiving unit 132 can be the molded body 102 of a

Supply winding device 136, on which the molded body 102 can be wound. The shaped body 102 can then be supplied as rolled goods to an entity that manufactures products such as wipes or textiles based on the shaped body 102.

In order to be able to carry out a method according to an exemplary embodiment of the invention according to FIG. 1 by means of the apparatus 100 according to FIG. 2, material is supplied as starting material 110 in whole or in part, which from a previous Lyocell process (can also be carried out with an apparatus 100 according to FIG ) was won.

In the following, examples of a method management according to exemplary embodiments of the invention are described:

Example 1 :

In an exemplary application of the method according to an embodiment of the invention, cellulose fibers produced according to the Lyocell method were used as starting material for carrying out a further Lyocell method on a laboratory system. Specifically, short cut Lyocell fibers with a fiber length of 3 mm were used. This starting material was mixed with an aqueous NMMO solution without further pretreatment in order to produce a spinnable solution from it. This spinning solution was then regenerated in the form of filaments and cut into staple fibers with a titer of 1.3 dtex and a length of 38 mm. The characterization of the fibers obtained in this way showed that the properties obtained (in particular

Fiber strength (FFk) and elongation (FDk)) are essentially comparable with those Lyocell fibers that are produced on the same laboratory system with typical

Chemical pulp can be achieved as a starting material (see Table 1).

Example 2:

The Lyocell short cut fibers from Example 1 were, without further

Pretreatment, mixed with lyocell-compatible chemical pulp as an additional starting material. In this example, the total amount of mixed raw materials consisted of 20 percent by weight of the Lyocell short cut fibers and 80 percent by weight

Weight percent of the chemical pulp. The mixed raw materials were then used in a subsequent Lyocell process with NMMO

Spinning solution produced and staple fibers made from it. As in Example 1, it was found that the properties of the Lyocell fibers produced in this way essentially correspond to those which can be produced on the same laboratory system with chemical pulp as the sole starting material (see Table 1).

Table 1: Fiber properties

FIG. 3 shows a cellulose fiber 200 produced by means of a Lyocell process in cross section. The one made using a Lyocell process

Cellulose fiber 200 has a smooth, round outer surface 202 and is filled with cellulose material homogeneously and free of macroscopic holes. It can therefore be clearly distinguished by a person skilled in the art from cellulose fibers produced by means of a viscose process (see reference number 204 in FIG. 4) and from cellulose fibers from cotton plants (see reference number 206 in FIG. 5).

FIG. 4 shows a cellulose fiber 204 produced by means of a viscose process in cross section. The cellulose fiber 204 is cloud-shaped and has a plurality of arcuate structures 208 along its outer circumference.

FIG. 5 shows a natural cellulose fiber 206 from a cotton plant in cross section. The cellulose fiber 206 is kidney-shaped and has a material-free lumen 210 inside as a completely enclosed cavity.

Based on the significant geometric or structural differences of the fibers according to Figure 3 to Figure 5, it is possible for a person skilled in the art to unambiguously determine, for example under a microscope, whether a cellulose fiber has been formed using the Lyocell process, the viscose process or, of course, in a cotton plant is.

In addition, it should be pointed out that “having” does not exclude any other elements or steps and “a” or “a” does not exclude a plurality. Furthermore, it should be pointed out that features or steps that have been described with reference to one of the above exemplary embodiments also in combination with other features or steps of others described above

Embodiments can be used. Reference symbols in the

Claims are not to be regarded as limiting.
Patent claims

1. A method for producing a regenerated cellulose molded body (102), the method comprising:

Feeding (78) a produced by means of a Lyocell process

Cellulose-containing starting material (110), which is produced by dissolving (52) a cellulose source (48) in a solvent to produce a spinning mass, by extruding (54) the spinning mass and by subsequent precipitation (56) in a spinning bath;

Dissolving (68) the cellulose-containing starting material (110) in a solvent (116) for producing a spinning mass, the dissolving (68) of the starting material (110) taking place by means of a direct dissolution process; and

Extrusion (70) and subsequent precipitation (72) of the spinning mass in a spinning bath (191), whereby the shaped body (102) is obtained.

2. The method according to claim 1, wherein the spinning bath (191) for the starting material (110) comprising dissolved cellulose comprises water and solvent.

3. The method of claim 1 or 2, wherein the spinning bath for the dissolved cellulose source (48) comprises water and solvent.

4. The method according to any one of claims 1 to 3, wherein the shaped body (102) is a filament, a fiber, in particular a continuous fiber, a film, a sponge or a ball.

5. The method according to any one of claims 1 to 4, wherein the method comprises performing a further Lyocell process (80) which comprises:

Dissolving (68) the shaped body (102) in a solvent to produce a spinning mass; and

Extrusion (70) and subsequent precipitation (72) of the spinning mass in a spinning bath, whereby another shaped body is obtained.

6. The method according to any one of claims 1 to 5, wherein the method comprises comminuting (62), in particular mechanical comminution, further

in particular shredding the starting material (110) before dissolving (68) the starting material (110) in the solvent (116).

7. The method according to any one of claims 1 to 6, wherein the method dissolving the starting material (110), in particular present as a solid, in the solvent (116) without chemical pretreatment of the starting material (110), in particular without chemical cleaning and / or without Adjustment of the viscosity.

8. The method according to any one of claims 1 to 6, wherein the method involves at least partial cleaning (66), in particular chemical cleaning, of the starting material (110), in particular present as a solid, before dissolving (68) the starting material (110) in the solvent (116).

9. The method according to claim 8, wherein the cleaning (66) comprises at least partial removal of dyes, in particular by means of bleaching, from the starting material (110) before dissolving (68) the starting material (110) in the solvent (116).

10. The method according to any one of claims 1 to 6 or 8 or 9, wherein the starting material (110) is at least partially freed from crosslinking agents which cross-link fibers of the starting material (110) before it is precipitated (72), in particular before it is released (68), in particular by means of an alkaline and / or an acidic pretreatment.

11. The method according to any one of claims 1 to 10, having at least one of the following features:

wherein the starting material (110) is wholly or partially formed from leftovers from clothing manufacture and / or from old clothes;

the starting material (110) being mixed (64) with another starting material containing cellulose before it is precipitated (72), in particular before it is dissolved (68) in the solvent (116), the other starting material in particular being at least one material from one group which consists of wood pulp, rag pulp, textiles, clothing, cotton and cellulose produced by means of a viscose process;

wherein the method comprises post processing (74) the precipitated

Has molded body (110);

wherein the dissolving (68) of the starting material (110) and / or the dissolving (52) of the cellulose source (48) by means of a direct dissolution process and / or by means of tertiary amine oxides, in particular N-methylmorpholine-N-oxide, and / or by means of ionic liquids as Solvent (116) occurs;

wherein the dissolving (68) of the starting material (110) and the subsequent precipitation (72) of the shaped body (102) by means of a Lyocell process

is carried out.

12. The method according to any one of claims 1 to 11, wherein the method comprises producing the cellulose-containing starting material (110) by means of:

Dissolving (52) the cellulose source (48) in the solvent to produce the spinning mass; and

Extrusion (54) and subsequent precipitation (56) of the spinning mass in the spinning bath.

13. The method according to any one of claims 1 to 12, wherein fibers (200) of the starting material (110) or the molded body (102) have a smooth, round outer surface (202).

14. Use of a cellulose-containing starting material (110) produced by means of a first lyocell process for producing a molded body (102) containing cellulose by treating the starting material (110) by means of a second lyocell process.

15. Use according to claim 14, wherein as at least part of the starting material (110) textiles, in particular remnants of a

Clothing manufacturing and / or used clothing.