EP2906742B1 - Spinning bath and method for solidifying a moulded part - Google Patents

Description

The present invention relates to coagulation baths for spinning processes.

Celluose and other polymers can be dissolved in suitable solvents and converted by controlled solidification into a desired shaped body. When this shaped article is filaments, fibrils and the like, it is also referred to as a spinning process. For example, cellulose is dissolved in aqueous solutions of amine oxides, particularly solutions of N-methyl-morpholine-N-oxide (NMMO), to produce spin products such as filaments, staple fibers, films, etc. from the resulting dope. This is done by precipitation of the extrudates in water or dilute amine oxide solutions after the extrudates of the extrusion die are passed through an air gap in the precipitation bath.

The US 4,416,698 relates to an extrusion or spinning process for cellulose solutions to form cellulose into filaments. Here, a fluid spinning material - a solution of cellulose and NMMO (N-methylmorpholine-N-oxide) or other tertiary amines - formed by extrusion and placed in a precipitation bath for solidification and expansion. This method is also known as the "lyocell" method.

The US 4,246,221 and the DE 2913589 describe processes for producing cellulosic filaments or films wherein the cellulose is drawn in fluid form. It describes a spinning process in which cellulose is dissolved in tertiary amine oxide, wherein the resulting cellulose solution is forced through a nozzle tool, extruded through an air gap into a spinning funnel and withdrawn at the end of the spinning funnel as an endless thread. The inserted spinning funnel is equipped with a supply means and a laxative for the spinning bath.

The US 4,261,943 relates to a process for the production of shaped cellulose articles, wherein the surface of the spun threads is treated with a non-solvent.
Another procedure is in the US 5,252,284 described in the elongated form capillaries are used to form a cellulosic mass.

In the WO 92/07124 is a method for producing a Fibrillierungsreduzierten cellulose fiber described. The undried fiber is treated with a cationic polymer.

The WO 93/19230 A1 describes a further development of the lyocell process, in which the cellulose-containing spinning material is cooled immediately after molding before introduction into the precipitation bath.

The WO 94/28218 A1 describes a process for producing cellulose filaments in which a cellulose solution is formed into a plurality of strands via a die. These strands are brought through a gas-flow gap in a precipitation bath and discharged continuously.

The DE 555183 relates to spinning vessels for the wet spinning process, wherein a spider yarn passes through several vertical baths.

The WO 92/4871 describes a process for making a cellulosic fiber with reduced fibrillation tendency. The reduced fibrillation is achieved by allowing all the baths, with which the fiber comes into contact before the first drying, to have a maximum pH of 8.5. This control in a continuous bath is very complicated and requires chemicals for pH control.

In CA 2057133 A1 describes a process for the production of cellulose filaments wherein a dope is extruded and introduced via an air gap into a cooled NMMO containing water bath. The water bath contains a cycle for bath fluid regeneration with a spin bath supply and an outlet for controlling the NMMO components.

WO 03/014432 A1 describes a precipitation bath with central thread removal device below a cover film.

DE 10 2004 031 025 B3 shows a spinning device with spinning bath, which contains a Anströmkammer for spinning bath liquid, to form a laminar Fällbadströmung. In this case, a baffle plate is provided, which is intended to prevent flow of the filaments in spinning bath.

EP 1 900 860 A1 describes a 2-step coagulation bath of a spinner, wherein the baths may have different compositions of H ₂ SO ₄ .

US 4,510,111 A relates to a process for the production of acrylic fibers, in which a spinning solution is introduced directly and without an air gap in a first bath.

US 3,851,036 A relates to a spinning process for hollow fibers of acrylonitriles, which can be obtained by a spinning process and passing over several baths.

GB 679 543 A describes a viscose spinning process in a solution countercurrently variable composition.

US 4,056,517 A relates to the spinning of modacrylic copolymers, wherein the filaments are passed through several baths.

Maron et al. (Lenzinger reports, 76 (1997) 98-102 ) deals not only with the choice of raw materials but also with the coagulation conditions and their influence on NMMO fibers. It turns out that with strongly varying Spinnbadkonzentrationen only a very small influence on the fiber strength is given.

Michels and Kosan (Lenzinger Berichte, 86 (2006) 144-153 ) is concerned with the coagulation process of cellulose fibers with or without the addition of additives from spinning solutions consisting of NMMO or ionic liquids. The aim of these investigations is to determine the water retention capacity and the strength of the resulting fibers. The strength of the fibers produced is according to the examples largely independent of the solvent used, however, cause additional components (in admixture with cellulose) usually a significant decrease in strength. The examples also show a significant influence on the water retention capacity of the never-dried fiber. However, these differences are largely offset by one-off drying.

With the use of a two-stage precipitation using different precipitants (1st stage alcohol, 2nd stage water or aqueous NMMO) deals Fink et al. (Lenzinger reports, 78 (1998) 41-44 ). By this measure, a "skincore" effect is to be achieved, which should lead to a reduced fibrillation tendency of the lyocell fibers.

It is an object of the present invention to provide optimized precipitation baths for spinning processes in order to specifically influence the fiber properties, in particular the fibrillation tendency and the swelling of the fibers. It is also an aim to allow accurate control of the precipitation bath composition - also because solvents used in the lyocell process are expensive for cellulose such as NMMO and the like - and to efficiently recycle or recover the solvents.

The invention relates to a coagulation bath with a Koagulationsflüssigkeitszulauf, wherein the coagulating fluid inlet has one or more orifices which are below the coagulating liquid level of the coagulating bath or at least one coagulating liquid inlet is located below the coagulating liquid level of the coagulating bath and having a body entry area solidified in the coagulating bath, the coagulating liquid inlet being one or more Has orifices, which are below the inlet area and are directed to introduced into the coagulation bath molded body, so that the moldings are flown in operation with supplied coagulation liquid. The present invention is further set forth by further aspects and by methods in which the inventive devices are used, which are all combinable with each other. The invention is defined as set out in the claims. According to the invention, the elongation of the molding is optimally controlled by the gentle and controlled precipitation in every aspect of the invention.

The present invention provides a coagulation bath having a coagulating liquid inlet and a molded article entry area solidified in the coagulation bath, the entrance area being provided at a position where the coagulation liquid is coagulated with coagulating liquid, the coagulating liquid inlet being one or more Has orifices, which are below the inlet area and are directed to introduced into the coagulation bath molded body, so that the moldings are in operation with supplied or fresh coagulation liquid.

The shaped bodies according to the invention are preferably filaments. Accordingly, according to the invention, the coagulation bath is also referred to as spin bath. Spinning bath and coagulation bath are used interchangeably herein. The shaped bodies can also be foils or other shaped bodies with any desired cross section. The moldings are üblichicherweise continuously formed by extrusion and are therefore also referred to as continuous moldings with indefinite length.

More particularly, the present invention relates to a spin bath having a coagulating liquid feed and a filament entry region which solidifies in the spinning bath wherein the entry region is provided at a position at which the liquid surface of the coagulation liquid is filled with coagulating liquid, characterized in that the coagulating liquid feed has one or more orifices which are below the entry region and are directed towards the filaments introduced in the spinning bath, so that the filaments are supplied with supplied coagulation liquid in operation.

A spin bath according to the invention is usually positioned under an extrusion apparatus in which the still fluid moldings or filaments are extruded. In the lyocell process, the filaments pass through an air gap in which the threads can optionally be supplied with air, and then enter the spinning bath. The air gap height may, for example, be between 5 mm and 40 mm, in particular between 10 mm and 30 mm. In the air gap, the shaped bodies or spun yarns can be stretched, which improves the textile properties of the obtained solidified products in some cases. In the invention, stretching is optional and may or may not be performed. At a certain position in the spin bath, the moldings enter the bath and coagulate as determined by the coagulation liquid, which is usually a non-solvent of the molded body mass. The molding composition is preferably cellulose. Spinning baths usually have a Koagulationsflüssigkeitszulauf to renew the coagulation liquid in the spinning bath. Since the moldings contain solvents, the composition of the spinning bath could be changed without controlled feed, whereby a time-varying coagulation property could affect the consistency of the moldings. Coagulation is usually discharged with the moldings from the bath. The bath can also have a separate outlet for coagulation fluid.

The flow of the fluid moldings serves the purpose of exchanging solvent and non-solvent between the fluid moldings and the Koagulationsbad and can be accomplished via various devices.

According to the present invention, the mouths of the Koagulationsflüssigkeitszulaufs are positioned within the spinning bath and below the inlet region of the moldings. The mouths are on introduced into the coagulation moldings directed, so that the moldings are flown in operation with coagulation liquid.
This provides constant coagulation conditions, thereby increasing consistency and allowing precise control of coagulation conditions, for example to affect fibril tendency as desired. For example, it is preferred that in this stage, the moldings do not completely shock-like coagulate, but only the surface is coagulated. In a further stage, after the area in which the shaped bodies are flown with coagulation liquid, the threads are further or completely solidified by expulsion of the solvent. In the meantime, the threads can remain in a gel-like state. This second stage can still be done in this first spin bath or in another separate spin bath.

The mouths of the coagulating fluid inlet are, in preferred embodiments, laterally onto the shaped bodies, e.g. Spun threads, directed in the spinning bath. The lateral flow causes an unimpeded passage of the shaped body through the spinning bath, which is supplied by the flow coagulation liquid or fresh coagulation liquid is taken from the threads. As a result, the coagulation is accomplished at least on the surface of the moldings to controlled conditions.

The orifices are preferably arranged centrally in the spinning bath, in particular preferably in a horizontal orientation. The exact position in the spinning bath is not essential, but it is a position at the edge of the spinning bath to distinguish, which is not or only negligibly slightly suitable for direct flow against the moldings to achieve the effects of the invention.

The mouths of the liquid supply line are directed in preferred embodiments obliquely against the extrusion direction of the spun yarns or in the direction of the liquid surface of the spinning bath (up), but may also be directed perpendicular to the extrusion direction of the filaments or even obliquely downward (in the extrusion direction). Also a horizontal or horizontal arrangement (eg substantially parallel to the liquid surface) is possible. The angle between the transport / extrusion direction of the moldings and the flow direction of the supplied coagulation liquid at the mouths is preferably between -90 ° (down) and + 90 ° (up) between -40 ° (down) and 80 ° (up), more preferably between -30 ° and 70 °, especially preferably between -25 ° and 65 °, between -30 ° and 60 ° or between -35 ° and 55 °.

In a further embodiment, in addition to a first liquid feed line, further liquid feed lines may be provided which are positioned both below and above the liquid surface and are either supplied together with the first liquid feed line or else fed separately.

The orifices are positioned in further preferred embodiments at a distance of 1 mm to 50 mm from the molded bodies transported through the coagulation bath. The distance is the geometrically least possible distance, e.g. determined by a normal to the spinning direction (extrusion direction) or the direction in which the shaped bodies are transported away by the spinning bath (for example, pulled over a deflection roller). More preferably, the distance is from 2 mm to 45 mm, from 3 mm to 40 mm, from 4 mm to 35 mm, from 5 mm to 30 mm from 6 mm to 25 mm, from 7 mm to 20 mm or from 8 mm to 15 mm. By a smaller distance, a mixing of the supplied coagulation liquid with coagulation liquid already present in the spinning bath, which is durchmengt with introduced through the moldings solvents, reduced.

In order to reduce the mixing of the two coagulation liquids, deflecting elements can also be provided in the spinning bath in the region of the orifices. The deflecting elements shield the flow of the coagulation liquid supplied onto the shaped bodies introduced into the spin bath, in particular in the said entry region on the surface of the coagulation liquid, before the influx of coagulation liquid present in the spin bath.

The orifices are provided below the surface (also referred to as level) of the coagulating liquid in the spinning bath and, in this function, are also suitable for effecting an external level control of the coagulating liquid in the spinning bath. Preferably, the orifices are 1 mm to 500 mm below the surface or level, in particularly preferred embodiments, these are 2 mm to 400 mm, 3 mm to 300 mm, 4 mm to 250 mm, 5 mm to 200 mm, 6 mm to 150 mm, 8 mm to 100 mm, 10 mm to 80 mm, 12 mm to 60 mm, 14 mm to 40 mm or even 15 mm to 30 mm below the surface or the level of the coagulating liquid in the spinning bath. Preferably, the orifices are in vertical alignment in the upper half of the Koagulationsflüssigkeitsstandes, which is necessary for the operation.

Preferably, in combination with all aspects of the invention, the surface of the coagulating liquid is substantially in direct contact with the gas (especially air) of the air gap, i. the coagulation fluid is not covered with a foil. Alternatively, a cover layer can also be applied to the spinning bath surface. Also preferably, the coagulation liquid is not horizontally divided into two zones but represents in the spin bath a single by convection durchmischbares medium.

In preferred embodiments, the coagulation bath has a liquid container, e.g. a tub, and a fluid conduit into the fluid container having one or more ports below a predetermined fluid level in the fluid container, and a fluid level controller outside the fluid container hydraulically communicating with the fluid in the fluid container via the fluid conduit, the fluid level controller providing an opening on a predetermined one Level contains. Thereby, the liquid level in the liquid container in the manner of a communicating vessel with the external liquid level controller is set or the liquid level in the liquid container is determined by the hydraulic connection.

According to the invention, a liquid level controller is provided outside the liquid container of the coagulation bath filled with coagulating liquid (also referred to herein as spinning bath). Spinning baths usually have a Koagulationsflüssigkeitszulauf to compensate for at least the liquid container by Mittransport with the transported through the spinning bath molding. For increased renewal of the liquid may optionally have the spin bath and a separate liquid outlet. Preferably, however, in the spinning bath no separate liquid outlet (apart from the liquid which is discharged with the filaments ("drag losses") - this is not referred to herein as a liquid spout). The coagulation liquid is usually contaminated by various substances, solvents and non-solvents of the molding material mass or other substances of the production process. Contaminating substances can be, for example, metal ions which can be dissolved out of the extrusion apparatus (eg from steel, stainless steel, ceramics, sintered metals, aluminum, plastic, non-ferrous metals or precious metals). Preferred materials are all iron, iron alloys, chromium-nickel steels, nickel steels (eg Hastelloy materials, titanium, tantalum).

The external liquid level controller offers a possibility to supply only as much liquid to the spinning bath as is taken from the coagulation tank due to drag losses caused by the discharged filament ribbon. This allows a particularly gentle and turbulence-free supply of coagulation with coagulation liquid.

In addition, this allows an overflow, which is given by the opening in the regulator, to keep external of the spinning bath and thus free from contamination or Koagulationsflüssigkeitszusammensetzungsveränderungen, which otherwise occur during the spinning process to keep. For this purpose, the liquid level controller is preferably combined with the liquid feed. For this purpose, the liquid level controller on the liquid inlet. In the liquid level controller thus the amount of inflow into the bath is controlled by the position of the opening and thus the level in the bath. A line from the liquid level controller into the spinning bath then passes the coagulating liquid into the spinning bath. The line into the bath opens in particular below the Koagulationsflüssigkeitsniveaus as described above - in particular to accomplish the hydraulic connection with the liquid level controller, but also to feed in preferential embodiments as described above, the entering into the spinning bath moldings directly with supplied (fresh) coagulation liquid. Therefore, the liquid line preferably leads into the interior of the liquid container, for example a trough, wherein the openings lie in the interior of the liquid container. Particularly preferably, the openings are in the middle, that is not on the edge of the liquid container as described above.

Preferably, the height of the opening in the liquid level controller is height adjustable. For example, the height of the opening can be designed to be height-adjustable by rotation of a rotatable element. By the height adjustment, for example, the level differences from 5 mm to 200 mm, preferably from 10 mm to 150 mm, from 15 mm to 100 mm or from 20 mm to 50 mm vary.

The overflow from the opening can be used to feed a subsequent washing stage. A subsequent washing step may be another bath into which the shaped bodies are introduced after coagulation.

In a further embodiment, the coagulation bath device has a first liquid container ("coagulation liquid container") with a first coagulation liquid, and a second liquid container ("wash container") with a second coagulation liquid, and a shaped body deflection device for guiding shaped bodies from the coagulation container into the wash container the first coagulation fluid may have a different concentration of coagulant than the second coagulation fluid and / or another temperature. Of course, this aspect can also be combined with all of the aforementioned features of the invention, wherein, in particular, the first liquid container or its fill level controller can be made as described above.

The coagulating liquid container in combination with the subsequent washing container, for example each formed as a tray, can be used to produce other coagulation conditions. For example, in the first container, only the surface of the moldings can be solidified and the complete solidification can be carried out in the second container (for example by thorough washing out of the solvents remaining in the moldings). In the liquid, the amounts of solvent are reciprocal to the amount of coagulant. Preferably, in the first container is a higher solvent concentration or a lower coagulant concentration than in the second container or vice versa. Depending on the coagulant concentration, gentle or rapid coagulation can be carried out in the first and / or second container. As a result, product parameters such as fibrillation can be controlled in a controlled manner, depending on the shape of the molded body and the cross-sectional dimension.

Preferably, the concentration of solvent, e.g. a tertiary amine oxide, particularly preferably NMMO, in the first coagulation bath in the range from 15% to 50%, preferably from 20% to 40% (all percentages in% by weight). Preferably, in the first bath no shock precipitation but gentle precipitation is accomplished, e.g. by the presence of solvent. Here, in particular, the moldings are only incompletely coagulated, so do not durchkoaguliert to the core. According to the invention, the elongation of the molding is optimally controlled by the gentle and controlled precipitation in every aspect of the invention.

Due to the use of different coagulation baths different treatments of the moldings can be achieved. Preferably, the shaped bodies are not completely solidified in the first coagulation bath, but converted into a gel-like state. Preferably, the shaped bodies are still drawn in the first coagulation bath, which due to the different degrees of coagulation in the inner and outer region of the moldings causes particularly interesting properties of the resulting finished shaped body, in particular threads.

In preferred embodiments, the second liquid container has a separate liquid inlet from the first liquid container.

The second liquid container may have a liquid drain separately from the molded article discharge. The liquid drain can be an overflow. Preferably, the liquid which is drained from the first coagulation container through the shaped bodies, such as filament bundles, is introduced into the second liquid container. This efficiently reuses expensive solvents or coagulation fluids.

Preferably, the liquid inlet of the first and / or second liquid container outside the liquid container with an external liquid level controller, in particular as already described above.

The invention relates to other methods for solidifying shaped articles using any of the coagulation baths or devices described herein.

In particular, the invention relates to a process for the solidification of moldings, wherein the fluid moldings are guided into a coagulation bath with a coagulating liquid, wherein in the coagulation bath, the moldings into the coagulation bath supplied coagulation be flowed. For this purpose, coagulation liquid lines can open into the coagulation bath, so that the openings are directed onto the shaped bodies as already described herein.

Preferably, in the process for solidifying shaped bodies, the fluid shaped bodies are guided into a coagulation bath with a liquid container with a coagulating liquid, wherein the level of the coagulating liquid is predetermined by a liquid level controller located outside the liquid container, preferably with an external liquid level controller as described above. Preferably, coagulation liquid supplied to the bath is supplied via the liquid level controller. First, the liquid is fed into the regulator and connected via a hyrdaulische connection through another line to the bathroom. Through this connection, liquid flows from the regulator into the bath, depending on the level in the bath to equalize the liquid with the level of the opening.

Preferably, in the process for solidifying moldings in a coagulation bath apparatus having at least two separate liquid containers (eg tubs in a first liquid container) moldings are partially solidified and passed into a second liquid container, preferably after discharge from the first liquid container via a diverting and / or bundling apparatus In the two liquid containers, the moldings can additionally be washed out and further solidified, different conditions can be determined in the two or more liquid containers, in particular hot-melting moldings can be cooled and solidified in two controlled stages by different temperatures be washed in at least two stages from the moldings under different conditions.

In order to shape the shaped bodies, the outlet openings on the extruder can be chosen in any desired form. Possible are elongated openings for forming films or small, round openings for forming filaments or threads. Preferably, the openings are a maximum of 2 mm, a maximum of 1.5 mm, a maximum of 1.2 mm, a maximum of 1.1 mm, a maximum of 1 mm narrow or in diameter. The openings may be at least 0.1 mm, at least 0.2 mm, at least 0.3 mm, at least 0.4 mm, at least 0.5 mm, at least 0.6 mm, at least 0.7 mm, at least 0.8 mm, at least 0.9 mm narrow or be in diameter. After exiting the material is indeed in ge Shaped state, but still in fluid phase.

Preferably, a plurality of extrusion openings on the extruder or a plurality of moldings are provided side by side. The extrusion openings may be on a cambered, i. curved, extrusion plate may be provided, wherein preferably the curvature angle a at the edge of the extrusion plate to the extrusion is an acute angle. The curvature angle α is preferably less than 85 °, in particular less than 80 °, less than 75 °, less than 70 °, less than 65 °, less than 60 °, less than 55 °. By a curvature, the profile of the attachment of the extrusion openings can be adapted to the profile of the surface of a liquid in the coagulation. By inflow of the shaped bodies into the coagulation bath, the surface of the liquid is curved there, whereby, when the extrusion openings are guided flatly, the middle shaped bodies require a longer travel time than the outer ones. As a result, inhomogeneities can arise due to different residence times in the gas gap. These are inventively avoided.

In the coagulation bath, media, liquids and / or temperatures can be provided in which the shaped bodies solidify. For example, liquids or solutions can be used in which the material is insoluble and thus fails. Alternatively or additionally, lower temperatures may be selected at which the material solidifies. By at least temporary continuous precipitation, the shaped bodies according to the invention, e.g. Filaments, threads or films are generated. The moldings can be discharged continuously or discontinuously from the coagulation bath. The liquid in the coagulation bath can also be renewed continuously or discontinuously. The collecting bath can be tempered to a certain temperature, e.g. by heating or cooling elements or by controlling the medium change.

The shaped bodies (eg spun threads or fibers) can consist of a thermoplastic mass, in particular of a viscous fluid which is solidified in the coagulation bath. Preferably, the composition is selected from cellulose solutions, solidifiable fluids, especially "hot-melts", such as polymers, polycarbonates, polyesters, polyamides, polylactic acid, polypropylene, etc. Cellulose solutions are, in particular, cellulose-amine oxide solutions, in particular solutions of tertiary amine oxide solutions. An example is a cellulose-NMMO (N-methylmorpholine-N-oxide) solution, as in US 4,416,698 or the WO 03/057951 A1 described. Preferably, cellulose solutions ranging from 4% to 23% cellulose are used for processing into extrusion products. The shaped bodies preferably contain solidified cellulose in a coagulation liquid. The solution may be a mixture of water and a tertiary amine oxide such as NMMO, most preferably aqueous solutions. The solvent, eg NMMO, should be present in the spin bath (or baths) in a concentration sufficiently low to precipitate cellulose. The solvent is introduced into the spinning bath (s) by the moldings and should be maintained at a low enough level by renewing the coagulating liquid through the feed to achieve the desired degree of coagulation in the respective spinning bath.

The solution of the molding material may be an aqueous solution. The solution may be a thixotropic fluid, in particular a spinning solution. The spinning solution may contain NMMO and cellulose, wherein the mass ratio of NMMO to cellulose is between 12 and 3, preferably between 10 and 4, or more preferably between 9 and 5.

Especially preferred is the mass ratio a) ("input") of NMMO to cellulose in the molding prior to introduction into the coagulation liquid between 12 and 3, preferably between 10 and 4 or between 9 and 5. Alternatively or in combination, in preferred embodiments the mass ratio b ) ("output") of NMMO adhering in and on the shaped body to cellulose in the shaped body when applied from the (first) coagulation bath is between 10 and 0.5, preferably between 8 and 1, in particular between 6 and 3. The ratio is particularly preferred the Massenverhälntisse a) and b) ("input: output"), the Masseverhälntisse a) and b) are as defined above, between 0.2 and 25, preferably between 0.3 and 10, in particular between 0.5 and 3 The mass ratios NMMO to cellulose in the shaped body can be selected by appropriate mixing of the substances (before the extrusion and thus before introduction into the coagulation bath). The Outputmasseverhälntis b) can by the amount of NMMO in the coagulation and / or the flow rate and the take-off speed of the moldings be controlled and in particular by devices for Abtstreifen or dripping adhering to the molding liquid. "In or on the molding adhering NMMO" is to be understood that the molding after treatment in the coagulation still contains solvent, especially in the core, and was coagulated only superficially ("im") and optionally on the molding liquid of the coagulation bath adheres (" at the"). Coagulation fluid, especially the first bath, may still have relatively high levels of solvent (NMMO). In particular, when the shaped body forms a filament bundle, high amounts of liquid can carry with it. These amounts of discharged quantities are preferably balanced by delivery via the Koagulationsflüssigkeitszulauf. If the ratio a: b> 1, NMMO must additionally be added to the coagulation liquid, since the amount of NMMO fed in via the fluidized moldings is insufficient for export and otherwise the amount of NMMO in the bath would decrease (which would also be a less preferred but nevertheless possible embodiment). The additional NMMO delivery is preferably made via the coagulation fluid feed.

When discharging NMMO from the coagulation bath on the moldings can be dispensed with another liquid flow.

Special materials have a melting temperature of at least about 40 ° C, at least 50 ° C, at least 55 ° C, at least 60 ° C, at least 65 ° C, at least 70 ° C, at least 75 ° C. The material may be at exemplary temperatures of at least about 40 ° C, at least 50 ° C, at least 55 ° C, at least 60 ° C, at least 65 ° C, at least 70 ° C, at least 75 ° C, at least about 80 ° C , at least 85 ° C, at least 90 ° C, at least 95 ° C, extruded and passed into the coagulation bath. Preferably, the zero shear viscosity of the fluid is in the range of 100 Pas to 20,000 Pas, more preferably between 500 Pas to 16,000 Pas.

The temperature of the first and / or second Koagulationsbads is preferably between 5 ° C and 60 ° C, more preferably between 10 ° C and 50 ° C or between 15 ° C and 40 ° C. In specific embodiments, the temperature of the second coagulation bath is at least 1 ° C, preferably at least 5 ° C cooler than the first coagulation bath.

The shaped bodies can be conveyed via a deflecting and / or bundling element, For example, a pulley (fixed or rotating) can be removed from the coagulation bath (or baths). In preferred embodiments, the take-off speed for removing the moldings from the first or second coagulation bath - which can be selected independently of one another - between 5 m / min and 100 m / min, particularly preferably between 10 m / min and 80 m / min, is particularly preferred between 20 m / min and 60 m / min, in particular between 25 m / min and 50 m / min.

In the first and / or second coagulation bath additives can be added to achieve certain product properties. For example, crosslinking agents, emulsifiers, surfactants, detergents or even colorants or dyes (also "colorless" dyes) can be added. The shaped articles may be subjected to treatment with an emulsifiable polymer, e.g. Polyethylene or polyvinyl acetate, or even be crosslinked with glyoxal. The Fibrillationsreduzierung solvent-spun cellulosic moldings can be achieved with Bireaktivfarbstoffen, glyoxal, a glycol, glycol ethers, polyglycol, polyglycol ethers, alcohols such as isoamyl alcohol, isobutanol or isopropanol.

For restraint of the coagulation liquids during removal of the molded articles from the baths, the baths may have wiper lips.

In addition, the invention relates to a molded article available or prepared by one of the methods of the invention.

The present invention will be further illustrated by the following figures and examples without being limited to these embodiments of the invention.

Characters:

• Fig. 1 shows an arrangement of the inventive Koagulationsflüssigkeitszulauf in a spin bath. From an extrusion device 1, filaments 2 or other shaped bodies are extruded and pass through an air gap into a spinning bath. The coagulation liquid surface or the level is indicated by reference numeral 3. The entrance area of the spun threads in the bath is between the crossing points of the lines 2 and 3. In the spin bath is a Koagulationsflüssigkeitszulauf, by a Line (shown schematically 4) is fed. Through distribution pipes 5a and 5b, shown in cross-section, the coagulation liquid is introduced via openings 6a and 6b in the direction of the spun yarns in the spinning bath. The flow of fresh coagulation fluid is marked with the thin dashed lines. She is carried away by the flow of the spider threads. Additional fluid inlets with appropriately designed mouths may be located above as well as below the level of the coagulating fluid surface.
• Fig. 2 shows an arrangement as in Fig. 1 and additionally shows deflecting elements 7a and 7b, which minimize an influx of coagulating liquid from the spinning bath to the entry region of the filaments, so that predominantly freshly infused coagulation liquid is present at the inlet region. Also shown is a deflection roller 8 for deflecting the coagulated filaments 9.
• Fig. 3 shows an arrangement as in Fig. 2 shown and shows the coagulation liquid line 4 and the trough 10 of the spinning bath. The coagulation liquid line 4 is connected to a liquid level controller 11. The controller has an opening 12, via which the level 3 is controlled in the spinning bath 10. About an arm 13, the controller is rotatable, whereby the opening 12 in height and thus the level 3 can be adjusted.
• Fig. 4 shows an arrangement as in Fig. 3 represents, wherein the distribution pipes 5 of the supply line - fixed together in a height-adjustable mounting device 14 - are positioned deeper in the tub. In this embodiment, a manifold is equipped with a guide roller 8 at the same time.
• Fig. 5 schematically shows a Spinningbadvorrichtung of two baths or troughs (10 and 15). In the tub 10, a first solidification of the spun yarns 2 is made. The coagulated spun yarns 9 are guided via deflecting rollers 8 into the trough 15, wherein the bundled threads 9 are further solidified by the presence of coagulating liquid, which may be different from the coagulating liquid of the trough 10 can be washed. The liquid level controller 11 is fed through a line 16 with coagulating liquid. Thus, the liquid level controller via the line 4 serves as a liquid inlet for the trough 10. The trough 15 may have a separate liquid inlet 17. The opening 12 of the regulator, which regulates the level in the tub 10, can lead to overflow into the trough 15 in order to additionally or alternatively feed it with coagulating liquid.
• Fig. 6 shows a spin bath apparatus of two baths (10 and 15) as in Fig. 5 described with the first tub 10 as in Fig. 4 shown.
• Fig. 7 shows a stripping and deflecting device (wiper lips) for moldings, which vertical and height-adjustable pulleys (which may be fixed or rotating) to reduce drag losses of the bath liquid or adjust to a desired level. This pulley is positioned over the bath so that dripping fluid is returned to the bath. This device can be provided for the coagulation bath and / or for the washing bath.
• Fig. 8 shows a stripping and deflecting device for moldings analogous to in fig. 7 shown with two instead of a vertical and height adjustable pulleys (marked with vertical and horizontal double arrows) above the bath.

Examples:

It has surprisingly been found that an effective solidification and coagulation system for the dry-jet wet spinning process can be constructed as follows and used for the molding of cellulosic materials and additives. As a molding composition, a composition of cellulose 12.9%, amine oxide (NMMO - N-methyl-morpholine-N-oxide) 76.3%, water 10.8% was used and fed to the spinning apparatus.

First, the spinning mass flow is divided into individual spinning positions or spinning groups and fed to the individual spinning positions. Through the extrusion openings, the mass is pressed under pressure and formed into the moldings, which in a Air gap between the extrusion openings and the coagulation be additionally stretched. A stretching of the moldings is not always desirable and does not always have to be done on the extrudates.

The shaped body is introduced into a coagulation bath. In this first coagulation or precipitation bath a pre-, partial or complete solidification of the shaped body is carried out, wherein for pre-, partial or complete solidification different compositions of the coagulation bath can be used. The pre-stretched, partially or fully solidified stretched shaped body obtains its desired product properties in the first coagulation bath and is brought from the first bath via a further deflection device into an underlying second bath for further treatment of the shaped body via a deflection and transport device located in the first bath.

The treatment in the first bath can be that coagulation, washing, damping, solvent exchange, impregnation, crosslinking of the molding with different chemicals and reagents can be carried out.

A further treatment in the second bath may consist in that a coagulation, washing, damping, solvent exchange, impregnation, crosslinking of the molding with different chemicals and reagents can be carried out. In the first bath, the coagulation liquid is supplied to the molded body close to the body and the surface. The first bath is characterized in that only as much precipitation or treatment or coagulation bath is supplied, as is carried out with the precipitate from the first bath. The precipitation or treatment or Koagulationsbad can be performed after the first bath via squeezing or Abstreiflippen, thereby ensuring that excess liquid is recycled to the first bath (dripping) before the precipitate for continuous further treatment is supplied to the second bath. Usually, the second bath is used for washing, from which the washed, treated manufactured precipitate is discharged via a deflection device mounted therein. The process can be extended by several washing or treatment stages at will.

All pulleys in the baths as well as the Koagulationsflüssigkeitseinmündungen can move independently or be designed to be fixed, in particular movable, in order to be able to flexibly set the treatment times in the first and / or second bath.

The inlet to the first coagulation bath can have an opening for controlling the inflow of coagulating liquid into the coagulation bath, wherein a control-related overflow is fed to the second coagulation bath. This overflow can be adjusted on the one hand via a free overflow edge or by means of control flap. table example 1 2 3 4 process parameters Spec. NMMO-INPUT (ratio of NMMO to cell in the spin jet) 9.83 6.12 5.02 5.87 off speed m / min 38,00 32,00 37,00 37,00 hole density Hole per mm ² 2.70 2.70 2.70 2.70 Frischbadtemperatur ° C 26.00 18,00 22.00 20.00 Frischbadkonzentration % 20.3% 17.5% 8.7% 0.0% Koagulationsbadkonzentration % 24.9% 29.4% 34.9% 40.5% Flottenverhältins Fleet Ratio Towing current to cellulose flow ~ 5 22.60 11.90 10,80 Liquor ratio overflow stream to cellulose stream ~135 - - - total fleet 140.00 22.60 11.90 10,80 Ratio of NMMO to cellulose Spec. NMMO-OUTPUT (NMMO dissipated by cable and pull-out current divided by cellulosic current 1.39 8.84 5.57 5.87 NMMO OUTPUT / INPUT ratio 0.14 1.44 1.11 1.00 fiber data titres dtex 1.31 1.33 1.29 1.38 Variation coefficient of the titer % 13,90 10.70 15.90 24,80 spinning behavior 1 ... good 5 ... bad 1-2 1-2 2 4 Nasscheuerzahl 695.00 230.00 189.00 312.00

Example 1 (see also table):

A spinning solution with a NMMO to cellulose ratio of 9.83 ("specific NMMO INPUT") was fed to a spinneret. The flat filament curtain extruded over the spinneret with a hole density of 2.7 holes per mm ² was passed through the coagulation bath at a take-off speed of 38 m / min.

At the end of the exchange, the filament curtain was bundled by means of a ceramic bundling roll onto a compact filament bundle.

Fresh liquid with a NMMO concentration of 20.3% and a temperature of 26 ° C was supplied.

By the forced bundling of the flat filament curtain into one At the end of the exchange route, hardly any coagulation bath could be removed from the coagulation bath, so that to achieve the desired NMMO concentration in the coagulation bath of 23.1%, much more fresh liquid had to be supplied than the positively bundled bundle of fibers could dissipate.

The amount of fresh fluid to the coagulation bath and the amount of overflow from the coagulation bath were measured and compared with the cellulosic effluent exiting the coagulation bath.

From the difference between the quantity of fresh liquid [kg / h] and the amount of overflow [kg / h] divided by the cellulose flow [kg / h], the "liquor ratio outward flow to cellulosic flow" was calculated.

From the division of overflow stream to cellulose stream, the "liquor ratio overflow stream to cellulose stream" could be determined.

• Der Überlaufstrom wurde einer gewichtsanalytischen Messung zur Bestimmung des NMMO-Gehalts [Gew.%] unterzogen.

The "total fleet" was calculated from the summation of the sub-fleets mentioned above:

• The overflow stream was subjected to a weight-analytical measurement to determine the NMMO content [% by weight].

To determine the amount of NMMO discharged by the tow-out stream and the bundle of fibers, the amount of NMMO overflow (calculated from the amount of overflow [kg / h] and NMMO content [% by weight]) was subtracted from the amount of NMMO fed to the system by means of the fresh bath and spinning jet.

As a result, the quantity of NMMO removed by the pulping stream and the bundle of fibers was related to the quantity of cellulose removed in order to obtain the "specific NMMO-OUTPUT".

The quotient of "specific NMMO-OUTPUT" by "specific NMMO-INPUT" ultimately represents how much NMMO are discharged from the spinning system via the fiber in relation to the amount of NMMO introduced by the spinning jet, with higher values tending to occur manifesting more gentle coagulation conditions.

The spinning behavior and the titre variance were satisfactory. Checking the fibrillating behavior by wet scrubbing gave typical values for standard lyocell fibers.

Example 2

A spinning solution with a NMMO to cellulose ratio of 6.12 ("specific NMMO-INPUT") was fed to a spinneret. The flat filament curtain extruded as in Example 1 was passed through the coagulation bath at a draw-off speed of 32 m / min.

At the end of the swap, the flat filament curtain was not bundled, but passed as a flat curtain over guide elements and thus supplied to the next treatment steps.

Fresh liquid with a NMMO concentration of 17.5% and a temperature of 18 ° C was supplied.

Since the flat filament curtain was led out of the bath without bundling at the end of the dipping section, coagulation liquid could be drained from the coagulation bath in sufficient quantities and the same amount of fresh liquid supplied to the desired NMMO concentration in the coagulation bath of about 30% (measured: 29, 4%).

The amount of fresh fluid supplied and the quantity of coagulation fluid dragged out could be determined by the experimental setup as in Fig. 3 to be kept in balance, no overflow from the coagulation bath had occurred.

The amount of fresh fluid was measured and compared with the cellulosic stream leaving the coagulation bath.

From the fresh liquid volume [kg / h] divided by the cellulose stream [kg / h], the "liquor ratio outward flow to cellulosic flow" was calculated.

Since there was no overflow, the "liquor ratio overflow to cellulosic" was calculated to zero. The "total fleet" thus corresponded to the liquor ratio Ausschleppstrom to cellulose stream.

Since no overflow stream occurred, the amount of NMMO discharged by the pullout stream and the bundle of fibers corresponded to the quantity of NMMO supplied to the system by means of fresh liquid and spinneret.

As a result, the quantity of NMMO removed by the pulping stream and the bundle of fibers was related to the quantity of cellulose removed in order to obtain the "specific NMMO-OUTPUT".

The quotient of "specific NMMO-OUTPUT" by "specific NMMO-INPUT" ultimately represents how much NMMO over the fiber in relation to the amount of NMMO introduced by the spinning stream be discharged from the spinning system, with higher values tend to manifest more gentle coagulation conditions.

• Überprüfungen des Fibrillierverhaltens anhand der Naßscheuerzahl ergaben deutlich bessere (niedrigere) Werte als dies bei Standard Lyocell Fasern zu erwarten war.

The spinning behavior and the titre variance were very satisfactory:

• Tests on fibrillating behavior based on wet scrub resistance showed significantly better (lower) values than expected for standard lyocell fibers.

Example 3

A spinning solution with a NMMO to cellulose ratio of 5.02 ("special NMMO-INPUT") was fed to a spinneret. The flat filament curtain extruded as in Example 1 was passed through the coagulation bath at a draw-off speed of 37 m / min.

At the end of the barter the flat curtain was led over guide elements and according to Figure 7 via a stripping device, which returns a part of the dragged coagulation bath back into the coagulation tank, withdrawn from the coagulation bath.

Fresh liquid with a NMMO concentration of 8.7% and a temperature of 22 ° C was supplied.

Coagulation liquid could be removed from the coagulation bath in sufficient quantities and the same amount of fresh liquid supplied in order to achieve the desired NMMO concentration in the coagulation bath of about 35% (measured: 34.9%).

The quantity of fresh liquid supplied and the quantity of coagulation liquid dragged out could be determined by the test arrangement as described in US Pat Fig. 3 in combination with Fig. 7 to be kept in balance, no overflow from the coagulation bath had occurred.

The amount of fresh fluid was measured and compared with the cellulosic stream leaving the coagulation bath.

From the volume of fresh liquid [kg / h] divided by the cellulose flow [kg / h], the liquor ratio of pullout flow to cellulose flow was calculated.

Since there was no overflow stream, the liquor ratio overflow stream to cellulosic stream was calculated to zero.

The total fleet thus corresponded to the fleet ratio Ausschleppstrom to cellulose stream.

• Da kein Überlaufstrom auftrat, entsprach die durch Ausschleppstrom und Fadenbündel abgeführten NMMO-Menge der mittels Frischbad und Spinnstrahl dem System zugeführten NMMO-Menge. In der Folge wurde die durch Ausschleppstrom und Fadenbündel abgeführte NMMO-Menge mit der abgeführten Cellulosemenge ins Verhältnis gesetzt um den "spez. NMMO-OUTPUT" zu erhalten.

The spinning behavior and the titre variance were satisfactory:

• Since no overflow stream occurred, the amount of NMMO discharged by the pullout stream and the bundle of fibers corresponded to the amount of NMMO supplied to the system by means of the fresh bath and the spinning stream. As a result, the quantity of NMMO removed by the pulping stream and the bundle of fibers was related to the quantity of cellulose removed in order to obtain the "specific NMMO-OUTPUT".

The quotient of "specific NMMO-OUTPUT" by "specific NMMO-INPUT" finally shows how much NMMO is discharged from the spinning system via the fiber in relation to the amount of NMMO introduced by the spinning jet, whereby higher values tend to manifest more gentle coagulation conditions ,

Tests of fibrillating behavior by wet scrubbing gave further improved (lower) values than did Example 2.

Example 4

A spinning solution with a NMMO to cellulose ratio of 5.87 ("specific NMMO INPUT") was fed to a spinneret. The experiment was carried out as in Example 3, however, the flat filament curtain was at the end of the exchange path according to Fig. 8 via 2 stripping devices (top and bottom), which return a part of the dragged coagulation back into the coagulation tub, withdrawn from the coagulation. Pure water was added to the coagulation bath at a temperature of 20 ° C.

Coagulation liquid could be removed from the coagulation bath in sufficient quantities and the same amount of fresh liquid supplied in order to achieve the desired NMMO concentration in the coagulation bath of about 40% (measured: 40.5%).

The quantity of fresh liquid supplied and the amount of coagulation liquid dragged out could be determined by the test arrangement as described in US Pat Fig. 3 in combination with Fig. 8 to be kept in balance, no overflow from the coagulation bath had occurred.

The quantity of fresh liquid was measured and related to the cellulose flow leaving the coagulation bath set.

From the volume of fresh liquid [kg / h] divided by the cellulose flow [kg / h], the liquor ratio of pullout flow to cellulose flow was calculated.

Since there was no overflow stream, the liquor ratio overflow stream to cellulosic stream was calculated to zero. The total fleet thus corresponded to the liquor ratio Ausschleppstrom to cellulose stream.

Since no overflow stream occurred, the amount of NMMO discharged by the pullout stream and the bundle of fibers corresponded to the amount of NMMO supplied to the system by means of the fresh bath and the spinning stream. As a result, the quantity of NMMO removed by the pulping stream and the bundle of fibers was related to the quantity of cellulose removed in order to obtain the "specific NMMO-OUTPUT".

The quotient of "specific NMMO-OUTPUT" by "specific NMMO-INPUT" ultimately shows how much NMMO is discharged from the spinning system via the fiber in relation to the amount of NMMO introduced by the spinning jet, higher values tending to result in gentler coagulation conditions manifest.

The spinning behavior and the titer variance were sufficient. Examination of the fibrillating behavior on the basis of the wet abrasion number continued to give good (low) values, however, in a worse way than was the case in Example 2 and Example 3.

Claims (15)

1. A coagulation bath with a coagulation liquid inlet (4), wherein at least one coagulation liquid inlet (4) is arranged beneath the coagulation liquid level (3) of the coagulation bath, and an entry region for shaped articles which are solidified in the coagulation bath, characterised in that the coagulation liquid inlet (4) has one or more mouths (6) which are arranged beneath the entry region and are directed to shaped articles (2) introduced into the coagulation bath, such that fed coagulation liquid flows against the shaped articles during operation.
2. The coagulation bath according to Claim 1, characterised in that the mouths (6) are directed from the side to the shaped articles (2) in the coagulation bath and/or the mouths are arranged approximately centrally in the coagulation bath.
3. The coagulation bath according to Claim 1 or 2, characterised in that the mouths (6) are aligned horizontally.
4. The coagulation bath according to one of Claims 1 to 3, characterised in that the mouths (6) are positioned at a distance of 1 mm to 50 mm from the shaped articles (2) transported through the coagulation bath.
5. The coagulation bath according to one of Claims 1 to 4, characterised in that the mouths (6) are directed at an incline in or against the direction of extrusion of the shaped articles (2) or in the direction of the liquid surface (3) or are arranged horizontally.
6. The coagulation bath according to one of Claims 1 to 5 with a liquid container (10), characterised by a liquid line (4) in the liquid container (10) with one or more mouths (6) beneath a predetermined liquid level (3) in the liquid container (10), and a liquid fill level regulator (11) outside the liquid container (10), which is hydraulically connected via the liquid line (4) to the liquid in the liquid container (10), wherein the liquid fill level regulator (11) contains an opening (12) at a predefined level, whereby the liquid level (3) in the liquid container (10) is established in the manner of a communicating vessel with the externally arranged liquid fill level regulator (11).
7. The coagulation bath according to Claim 6, characterised in that the height of the opening (12) in the liquid fill level regulator (11) is adjustable.
8. The coagulation bath according to Claim 6 or 7, characterised in that the liquid fill level regulator (11) has a liquid inlet (16).
9. The coagulation bath according to one of Claims 6 to 8, characterised in that the liquid line (4) leads into the interior of the liquid container (10) and the mouths (6) are located in the interior of the liquid container (10), in particular preferably as defined in one of Claims 2 to 6.
10. A coagulation bath device according to one of Claims 1 to 9, with at least two coagulation liquid containers (10, 15), with a first liquid container (10) with a first coagulation liquid, and a second liquid container (15) with a second coagulation liquid, and with a shaped article bundling device (8) for conveying shaped articles from the first liquid container into the second liquid container, wherein the first coagulation liquid has a concentration of coagulation agent and/or a temperature different from the second coagulation liquid.
11. The coagulation bath device according to Claim 10, characterised in that the second liquid container (15) has a liquid inlet (17) separate from the first liquid container (10), wherein the second liquid container has a liquid outlet (18), and/or the liquid inlet of the first liquid container is arranged outside the liquid container and is equipped with an externally arranged liquid fill level regulator (11), in particular preferably as in one of Claims 6 to 9.
12. A method for solidifying shaped articles, wherein the fluid shaped articles (2) are guided into a coagulation bath with a coagulation liquid, characterised in that, in the coagulation bath, coagulation liquid supplied into the coagulation bath flows against the fluid shaped articles for the purpose of exchanging solvent and non-solvent between the fluid shaped articles and the coagulation bath.
13. A method according to Claim 12, wherein the fluid shaped articles are guided into a coagulation bath with a liquid container (10) with a coagulation liquid, characterised in that the level (3) of the coagulation liquid is predefined by a liquid fill level regulator (11) located outside the liquid container, preferably by means of a liquid fill level regulator as defined in one of Claims 6 to 9.
14. A method according to Claim 12 or 13 for solidifying shaped articles in a coagulation bath device with at least two liquid containers (10, 15) separate from one another, wherein shaped articles are partially solidified in a first liquid container (10) and are conveyed via a bundling device (8) into a second liquid container (15), preferably after output from the first liquid container, and the shaped articles are additionally washed and solidified in the second liquid container.
15. The method according to one of Claims 12 to 14, characterised in that the shaped articles, before solidification in a coagulation liquid, are formed from dissolved cellulose, preferably a solution with a mixture of water and NMMO, in particular preferably wherein the coagulation solutions are aqueous solutions and possibly contain NMMO in a low concentration sufficient for precipitation of cellulose,
    especially preferably wherein the mass ratio a) of NMMO to cellulose in the shaped article before introduction into the coagulation liquid is between 12 and 3, preferably between 10 and 4, or between 9 and 5, and/or
    wherein the mass ratio b) of NMMO adhering in and on the shaped article to cellulose in the shaped article during output from the (first) coagulation bath is between 10 and 0.5, preferably between 8 and 1, in particular between 6 and 3, and/or
    wherein the ratio of the mass ratios a) and b), wherein the mass ratios a) and b) are as defined above, is between 0.2 and 25, preferably between 0.3 and 10, in particular between 0.5 and 3.

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