EP3505659A1 - Method and device for filament spinning with inflection - Google Patents

Abstract

The invention relates to a process for the preparation of solid cellulose filaments from a fluid of cellulose by extruding the fluid through multiple extrusion orifices to form fluid filaments and solidifying the filaments in a coagulation bath, the filaments being bundled in the coagulation bath and deflected as bundles above the coagulation bath level to be withdrawn from the coagulation, wherein the bundle of filaments on a deflection device assumes a deflection width, which is determined according to a formula, and a device therefor.

Description

The present invention relates to the shaping and treatment of extruded synthetic fibers after their solidification.

Background of the invention

Cellulose can be dissolved in aqueous solutions of amine oxides, in particular solutions of N-methyl-morpholine-N-oxide (NMMO), to produce from the resulting spinning solution spin-products, such as filaments, staple fibers, films, etc. This is done by precipitation of the extrudates in water or dilute amine oxide solutions after the extrudates are fed from the extruder via a gas gap into the precipitation bath. Usually, cellulose solutions in the range of 4% to 23% are used for processing into extrusion products. In the further course, the precipitated extrudates are conveyed on in the form of film or filament strands, with suitable roller draw-offs applying the required stretching forces (in the gas gap). This process is also called Lyocellverfahren or obtained cellulose filaments Lyocellfilamente.

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.

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.

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 into a precipitation bath through a gas-flow gap and discharged continuously.

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

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

The WO 97/33020 A1 relates to a process for producing cellulosic fibers, in which a solution of cellulose in a tertiary amine oxide is extruded through spinning holes of a spinneret, the extruded filaments are passed through an air gap, a precipitation bath and via a draw-off device, with which the filaments are drawn, which stretched Filaments are further processed to cellulosic fibers, wherein the stretched filaments during the further processing of a tensile stress in the longitudinal direction of not more than 5.5 cN / tex are exposed.

The DE 10200405 A1 describes a Lyocellvorrichtung with Beblasungsvorrichtung in the gas gap. Mentioned is a Fällbadvorrichtung in which a filament curtain is immersed in the precipitation bath, is deflected in the precipitation bath and leaves the precipitation bath obliquely upwards to a bundling device again. Since bundling on a single strand, a strong bundling is to be expected during the diversion.

In WO 02/12600 For example, a spinning process is described wherein the maximum economic spinning speed can be calculated from a formula reference based on fiber titer, spinline row number, and a variable operating parameter.

In WO 02/12599 a spinning process is described in which a string curtain is deflected in a coagulation bath and then brought together punctiform.

The WO 96/20300 describes deflection angle of filaments in Lyocellverfahren according to a formula reference.

A problem of filament damage by deduction is in WO 2008/019411 A1 taken up and treated by means of a mechanical spin-off device mounted in the spinning bath, this extraction device should also apply a part of the withdrawal forces during operation. In addition to the complex construction, the danger is not to be underestimated that individual very fine filaments can get caught in the mechanical construction and thus impair the function of the spinning process as well as the mechanical device.

The WO 2014/057022 describes serial spinning baths with different media.

Summary of the invention

In previous Lyocell methods, all the individual filaments (single extrudates) which bear directly on the deflecting device (for example a round bar) are pressed against the deflecting device by the normal forces resulting from the tensile force of the entire bundle. This can lead to tears and thread breaks as a result of the frictional resistance occurring. Especially with strong bundling, the high normal force resulting from the total withdrawal force is exerted on only a few individual filaments which are in direct contact with the deflection device. These few individual filaments can be severely damaged by the high Reibkraftbelastung, especially at high take-off speeds. To make matters worse, that the filaments in the coagulation bath swollen and possibly still in a hot state, whereby the mechanical strength is low.

The aim of the present invention is to minimize the frictional force load of each individual filament at deflection points, thus enabling higher productivity and higher spinning speeds. Such a frictional force occurs in spinning baths in which rigid deflection devices due to the medium must be used or deflection devices with driven or free-rotating rollers, such as. in a deduction mechanism for the filaments.

The present invention provides the user with a computational power to evaluate its system for the frictional load imposed on the filaments and, with appropriate provisions, to adjust the system so that the frictional force load on all filaments in direct contact with the diverter can be kept to a minimum.

A further object of the present invention is to ensure the manual handling of the filament curtain and accessibility to the deflection point in the treatment zone between the spinneret and the extractor without having to use expensive and trouble-prone piecing aids or take-off devices.

bestimmt ist, wobei L die Umlenkbreite des Bündels in mm, LZ die Anzahl der Extrusionsöffnungen, B der Umlenkwinkel berechnet aus 180° abzüglich des Umschlingungswinkels der Filamente um die Umlenkvorrichtung in Grad, v die Abzugsgeschwindigkeit der Filamente in Meter pro Sekunde, c_cell die Cellulosekonzentration des extrudierten Fluids in Masse-%, Q eine dimensionslose Lastzahl ist, wobei Q 15 oder kleiner ist. In Formel 1 hat ">" die Bedeutung von "größer als", "x" ist ein Muliplikationszeichen und "cos" bedeutet Kosinus.The invention provides a process for producing cellulose cellulosic filaments from a fluid of the cellulose, extruding the fluid through a plurality of extrusion orifices to form fluid filaments, preferably passing the fluid filaments through a gas gap, and solidifying the filaments in a coagulation bath Filaments in the coagulation bath be bundled and deflected as a bundle to be deducted from the coagulation above the Koagulationsbadniveau, wherein the bundle of filaments on a deflection device occupies a deflection width L, which according to the formula 1: $$\mathrm{L}>\left(\mathrm{2}\times \mathrm{lz}\times \cos \left(\mathrm{B}/\mathrm{2}\right)\times {\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">v</figure-callout>}}^{\mathrm{2}.\mathrm{5}}\right)/\left(\mathrm{10}\times {{\mathrm{c}}_{\mathrm{cell}}}^{\mathrm{0}.\mathrm{5}}\times \mathrm{Q}\right)$$

L is the deflection width of the bundle in mm, LZ is the number of extrusion openings, B is the deflection angle calculated from 180 ° minus the angle of wrap of the filaments around the deflection device in degrees, v the withdrawal speed of the filaments in meters per second, c _cell the cellulose concentration of the extruded fluid in mass%, Q is a dimensionless load number, where Q is 15 or less. In formula 1, ">" has the meaning of "greater than", "x" is a muliplication sign, and "cos" means cosine.

Likewise, the invention relates to a device suitable for carrying out this method, comprising an extrusion plate having a plurality of extrusion openings, a collecting tank for a coagulation bath, preferably a gas gap between the extrusion openings and the collecting container, a deflection device in the collecting container for deflecting a filament bundle from the collecting container, and a bundling device having a Umlenkbreite L of the filament bundle to the deflection caused, wherein the filament bundle to the deflection device assumes a Umlenkbreite L which satisfies the aforementioned formula 1 wherein L, LZ, B, v, c _cell and Q have the meaning given above, Q is 15 or less and v is at least 35 m / min, for which the device is thus designed.

According to the present invention, wide deflection widths L are usually obtained, therefore, the invention also relates to a method of producing solid cellulose filaments from a fluid of cellulose by extruding the fluid through a plurality of extrusion orifices, thereby forming fluid filaments, preferably passing the fluid filaments through a gas gap, and solidifying the Filaments in a coagulation bath, wherein the filaments are bundled in the coagulation bath and deflected as a bundle to be withdrawn above the coagulation bath level from the coagulation bath, the extrusion openings being arranged along a length LL and the bundle of filaments on a diverter a deflection width L occupies, which is at least 70% of the length LL. Analogously, the invention also relates to a device suitable for carrying out this method, comprising an extrusion plate having a plurality of extrusion openings, a collecting container for a coagulation bath, preferably a gas gap between the extrusion openings and the collecting container, a deflection device in the collecting container for deflecting a filament bundle from the collecting container, and a Bundling device which causes a deflection width L of the filament bundle on the deflection device, wherein the extrusion openings are arranged over a length LL and the bundle of filaments on the deflection device assumes a deflection width L of at least 70% of the length LL.

The following detailed description relates equally to the devices and methods, e.g. Preferred process characteristics also correspond to properties or suitabilities of the device or its corresponding components and preferred device features also correspond to agents used in the method according to the invention. All preferred features can be combined unless explicitly excluded. All process features, including those of the above, can be combined. All device features, including those of the above, can be combined.

figure description

• In Fig. 1 a liquid treatment zone is shown as a spinning funnel (6).
• Fig. 2a shows a spinneret system, combined with a spinneret in a rectangular shape.
• Fig. 2b shows a spinning trough system, combined with a spinneret in ring shape (5) and straight deflection device (2).
• Fig. 2c shows a spinneret system combined with a spinneret in annular form, wherein the deflection of the annular extrudate curtain via a toroidal deflection device with deflection angle (B ') takes place and the deflected Extrudatvorhang along the central axis of the annular nozzle is guided vertically upwards from the spinning bath.
• Fig. 3a shows a tub system with diversion and bundling. At the bundling device, a spinning curtain with width L and deflecting angle B deflected.
• Fig. 3b shows a tray system with two deflection devices, wherein, in contrast to Fig. 3a , at the second deflection no bundling is made. At the second deflection, a spinning curtain with width L and deflection angle B is deflected.
• Fig. 4 shows a deflection in a trigger mechanism, which has "M" marked driven rollers, in top view (left) and in side view (right). All rollers can be driven ( Fig. 4a ) or some ( Fig. 4b ). The transport of the filament bundles is indicated by an arrow. The bundles are deflected by an angle B (0 ° to 150 °) to rollers. "L" indicates the width of the filament bundle on the roller.

Detailed description of the invention

The invention relates to the deflection of filament curtains or at least unilaterally bundled filament bundles. The diversion takes place in the coagulation bath in order to transport the filaments out of the bath. During the deflection, the filaments are brought together in the normal to the deflection axis, so that the filaments lie in the first layer on a deflection device and in the other layers on each other. This results in the material stress as already mentioned, especially at high speeds. According to the invention, the deflection width has been increased by at any, even high speeds of e.g. 35 m / min or higher to remove the filaments.

The filaments are guided in the inventive deflection as a wide band. The term "filament bundle" therefore includes tapes of filaments guided together having a width and a height in cross-section, the width being greater than the height.

The above formula 1 with Q of 15 or smaller relates in particular to the redirection in the coagulation bath, in which the flocks are particularly susceptible to the friction effects mentioned in the summary due to the temperature control and the swelling conditions. The coagulation bath is part of the treatment zone of the extruded filaments. In the lyocell process, the filaments have not yet reached their final structure and stability. The structure and stability initially changes due to stretching (mainly in the gas gap) and solvent exchange (mainly in the coagulation bath). Material changes can still occur after export from the coagulation bath, so that the path of the filaments / extrudates between the spinneret outlet and a washing out of solvent from the filaments / extrudates, including a take-off unit, is referred to as a treatment zone. Since the extruded filaments have not yet their final shape, they are also referred to as "extrudates" in the treatment zone. A deduction mechanism is a device which applies the necessary warping forces for thread formation and the frictional forces that occur on the filaments / extrudates during transport from the spinneret to the withdrawal unit. Due to the hydrodynamic conditions, the danger of winders in the case of driven or free-rotating deflectors is very great within the coagulation bath, so that fixed deflectors are preferably used within the coagulation bath. Outside the coagulation bath, if possible, only a small deflection should take place with fixed deflectors, or free-turning or driven deflecting devices should be used. In free-turning or driven deflection devices, the filaments / extrudates are less susceptible to frictional effects, so that smaller deflection widths L calculated as calculated according to formula 1 are used. However, a certain width, in particular for deflecting the deduction mechanism, is still complied with since frictional effects also occur here. The extraction unit has the task, depending on the hole throughput (per extrusion opening) to ensure the required take-off speed. A take-off unit imparts the drawing speed to the filaments / extrudates by means of driven or several deflection devices, such as rollers or rollers. Here, the deflection force of the roll is first transferred to the internal filaments / extrudates, which in turn transmit the force to further outward filaments / extrudates. Therefore, the internal filaments / extrudates are more stressed than the outer, an inequality inventively minimized by observing a deflection that the inner filaments / extrudates are superimposed only by a limited number of external filaments / extrudates which a faster and efficient operation is preserved. Extrusion ports may be holes or holes in an extrusion plate, as well as capillaries. For all these possibilities, the number of Extrusion openings also called number of holes. The withdrawal can be made in a gas space into which the filaments enter after being discharged from the coagulation bath.

According to the invention, a machine part is referred to as a deflection device, which allows a change of direction of individual extrudates, extruded curtains or extrudate bundles, the deflection width L of the deflected curtain is preferably not influenced by the deflection itself.

In principle, such deflection devices can be designed as a rigid deflection device or rotating deflection device. Rotating deflection devices can be designed with or without drive. Rotating deflection devices have the advantage that low frictional forces between extrudate and deflection device can occur and thus an extremely gentle deflection can take place - with the exception of a deflection in a trigger mechanism when transferring forces from the deflection device to the filaments / extrudates. The disadvantage of rotating deflection devices, however, is that due to the stickiness of individual extrudates they can adhere to the rotating deflection device, whereby winder, tears and other disturbances can arise. Also problematic is the use of rotating deflection devices in liquids (in Koagulationsbad), because due to hydrodynamic vortices in the Umlenkeroberfläche the danger is very large that individual extrudates are entrained by these vortices on the circumference of the deflection device whereby winders, tears and other disorders triggered can be.

For use in spinning bath liquids but also in sticky, moist or otherwise adhering Extrudatvorhängen or bundles rigid deflection devices, for example in the form of rods, coils, cage deflectors or in any other form are preferred.

As materials for rigid deflection devices are all materials in question, which have the lowest possible Gleitreibungswerte. In addition to metals with and without coating also textile ceramics or plastic is possible.

Preferably, a deflection device is used in the coagulation bath. Two or more deflection devices are also possible in the coagulation bath, giving greater options for (larger) deflection angle B per deflection are possible. According to the invention formula 1 is fulfilled by the first, preferably also the second or even each deflection device in the coagulation bath. "First", "second" etc. in this sense refers to the procedural proximity to the extrusion and the order in which the filaments / extrudates pass the diverters.

Even after the coagulation bath in the treatment zone, the filaments / extrudates are kept at a certain deflection width as a band, since here too, in particular in a deduction mechanism, frictional forces act which can cause damage during deflection. However, the deflection width after the coagulation bath may be lower than in the coagulation bath, since negative effects on the filament stability due to temperature and swelling may be lower. Preferably, according to the invention outside the coagulation bath at least at a deflection width L _outside , which L according to formula 1 (with Q less than or equal to 15) divided by 30, preferably divided by 20, preferably divided by 10, in particular preferably divided by 5, is deflected and / or the filament bundle on this width L _outside (even between the deflecting) held - at least up to a trigger mechanism and / or a washing device. Alternatively, L can be calculated _externally according to formula 1, whereby a higher value for Q can be used, namely Q can here take on a value up to 300 or up to 250, eg 10-300 or 40-250. In a washing device, the filament bundle is usually fanned out wider to favor the washing process. L _outside can also be at least L according to formula 1 (with Q to 15), eg in the washing process.

L _outside (deflection or bandwidth outside the coagulation bath) can also be defined independently of L according to formula 1. Preferably, L _outside is chosen so that at the given take-off speed, a filament density per mm deflection width of at most 7000 dtex / mm, preferably of at most 6000 dtex / mm, at most 5000 dtex / mm, particularly preferably of at most 4000 dtex / mm results.

This deflection or bandwidth outside of the coagulation bath L is preferably maintained _outside at the immediate next deflection after exiting the filaments / extrudates from the coagulation, since here the filaments / extrudates are even more sensitive, and / or adhered to the deduction, since here due to a power transmission the filaments / extrudates are particularly affected become. Preferably, the filament bundles are always held at least on the _outside width L throughout the treatment zone or during the entire processing of the filaments / extrudates until snow-and / or winding up of the final products after leaving the coagulation bath. The processing process usually involves the following areas: spinning in the coagulation bath (as above), removing from the coagulation bath, drawing off via a draw-off, washing, drying, winding and / or cutting the filaments as final products.

Alternatively or additionally, a spinning process, including further processing, comprise the following steps: extrusion through a spinneret, passing the filaments / extrudates through a gas gap (in which preferably a gas stream is blown, see below) into a coagulation bath (precipitation bath), deflecting the filaments / extrudates in the precipitation bath, preferably by a deflection device relative to the spinneret, removing the coagulated filaments / extrudates from the coagulation bath, deflection of the filaments / extrudates outside the coagulation bath and without further bundling with other coagulated filaments / extrudates, feeding the filaments / extrudates to a take-off ( Also referred to trigger member or trigger device) and / or drawing device, as well as continuation to a filament receiving unit and / or drafting, washing, drying and possibly further steps as desired. The device according to the invention has appropriate apparatuses for this purpose. In a further embodiment, the method may comprise the following steps: extrusion through a spinneret, passage of the filaments / extrudates through a gas gap (in which preferably a gas stream is injected, see below) into a coagulation bath, deflection outside the coagulation bath, bundling or merging with further filaments / Extrudates, feeding the filaments / extrudates to one or more drawers, washing, drying and, if necessary, further steps, or apparatus therefor, as desired.

Some steps can be combined: so you can wash in the extractor. In each of the steps, the detailed or preferred embodiments mentioned herein may find application. Likewise, in a take-off unit, driven rollers or rollers may be combined with non-driven ones, such as in FIG CN 105887226 (A ). in the Deductor can also be a heat treatment, such as drying, eg as in CN 205133803 U be described. When starting the process, a piecing aid, as in CN205258674U described, be used; However, this is only to help and not essential.

Further steps or apparatuses for this can be provided. Thus, e.g. be dried after washing, or after the washer, a dryer may be provided, wherein prior to drying / drying one or more further treatment step (s) such. B. the finishing of the filaments / extrudates or a finishing device, can be provided. In addition, other process steps such as dyeing, crosslinking, ultrasonic treatments can be carried out before drying; or devices or apparatus are provided for this purpose.

At any process location until drying, preferably a cutting device (for cutting) or a winding device (for winding) may be interposed therebetween in order to produce staple fibers or continuous yarns from the endless filaments.

Preferably, at the drawing unit, a tensile force is exerted on the filaments / extrudates of less than or equal to 3 cN / dtex, preferably less than or equal to 2 cN / dtex or less than or equal to 1.5 cN / dtex.

The filament bundles of several spinning stations can be combined to form a combined overall bundle. Usually, such a combination takes place immediately after or at the exit from the coagulation bath, so that the downstream equipment parts, such as deduction or washing, can be applied to the entire bundle. The width L or L on the _outside is usually stated herein with respect to a spinning station and increases accordingly after the combination. L _outside , for example, per spinning position at least 8 mm, for example 8 mm to 100 mm, preferably 12 mm to 70 mm.

The bundling device refers to a machine part which narrows the deflection width of the extrudate curtain due to the geometric shape of the bundling device and thereby forms an extrudate bundle from a flat or tubular or also round or otherwise shaped curtain of extrudates. Optionally, a directional change of the shaped extrudate bundle is also forced by the bundling device. Thus, the Bundling device also be a deflection, apply to the rules of the invention and preferably embodiments. Bundling devices can be designed to be rigid or rotating analogous to the description of the deflection. The same materials can be used. For use in Spinnbadflüssigkeiten but also in sticky, wet or otherwise adhering Extrudatvorhängen or bundles rigid bundling devices in the form of rods, coils, cage deflectors, hooks, eyelets, U-guides or executed in any other form devices are preferably used.

The load factor Q is an empirical measure of the filaments superimposed on the deflection device. The lower, the more gentle the process. L must be selected the larger. Q should be 15 or smaller in the coagulation bath, preferably Q 12 or less, preferably 8 or less or 5 or less. Herein, Q is 2 or greater, preferably 3 or greater, or 4 or 5 or greater, more preferably wherein Q is 2 to 15, or more preferably 4 to 12. Possible values for Q are 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or any value in between. As mentioned above, Q can be larger outside the bath. Here, for L, the character L is _externally used with Q up to 300. Unless otherwise indicated, Q refers to a redirection in the coagulation bath.

The number of extrusion openings (also called number of holes, abbreviated "LZ") determines the number of filaments which must be deflected. The inventive method is designed especially for large, industrially useful sizes. Preferably, the number of extrusion ports LZ is 2000 or more, preferably 5000 or more, or 10000 or more. Regardless or in combination, LZ may be 500,000 or less, preferably 200,000 or less, 100,000 or less, or 50,000 or less. If larger amounts of product and thus a higher number of filaments are to be produced simultaneously, a plurality of extrusion devices according to the invention can be used to produce a plurality of parallel filament bundles or curtains, possibly in a common coagulation bath or even with a common deflection device. The hole numbers given above refer to a bundle or group of filaments which is deflected and bundled together.

The deflection angle B results from the angle of the enclosed to the deflecting filaments and the deflected filaments is included (see figures). A sharper angle exerts stronger shear and friction forces on the filaments. The sharper the angle, the larger must be increased (at the same other parameters of formula 1) L. Preferably, the deflection angle B is an angle of 10 ° to 90 °, preferably 20 ° to 60 ° or 25 ° to 45 °. Unless otherwise indicated, angle B refers to redirecting in the coagulation bath. Outside, eg in a fume cupboard and / or during washing, the deflection angle can be 0 ° to 150 °, in particular every angle in this area, as was specified for example for the angles in the coagulation bath.

According to the invention, high take-off speeds are made possible by the large deflection widths L. The filaments are pulled through the coagulation bath, usually with the help of a drainage system. The withdrawal unit itself is usually arranged downstream of the coagulation bath, the deflection device and possibly also the bundling device. According to the take-off speed, a corresponding deflection width L is selected. Preferably, the take-off speed (at the deflection device) is at least 35 m / min. The drawing speed v may be 36 m / min or more, preferably 40 m / min or more or 45 m / min or 50 m / min or more. Regardless or in combination, the take-off speed v may be 200 m / min or less or 150 m / min or less.

The fluid used in the process according to the invention is an extrusion medium. This is preferably a solution or mixture of cellulose and other medium components, such as solvents. The cellulose concentration is chosen in usual sizes for Lyocellverfahren. Thus, the cellulose concentration of the extruded fluid c _{cell can be} 4% to 23%, preferably 6% to 20%, in particular 8% to 18% or 10% to 16% (all% data in% by mass). The extrusion medium in the lyocell process is usually a cellulose solution or melt with NMMO (N-methylmorpholine-N-oxide) and water, as described in the introduction. Other solutions of cellulose, especially ionic solvents of cellulose, may also be used. Ionic solvents are for example in WO 2006/000197 A1 described and preferably contain organic cations, such as ammonium, pyrimidium or Imidazoliumkationen, preferably 1, 3-dialkylimidazolium halides. Water is also preferably used here as a solvent additive. Particularly preferred is a solution of cellulose and butyl-3-methyl-imidazolium (BMIM), for example with chloride as counterion (BMIMCl), or 1-ethyl-3-methyl-imidazolium (also preferably as chloride) and water.

The step of passing the fluid filaments through a gas gap in the process of the invention or the gas gap in the device according to the invention is optional, i. may be made / present or not. This step / means differentiates between wet spinning and dry wet spinning. In wet spinning, the filaments are introduced directly into the coagulation bath. In wet dry spinning, the gas gap is present and the filaments pass through it first before being introduced into the coagulation bath.

In the gas gap can optionally (and preferably, especially in large, industrially relevant equipment) blown a gas stream or provided in the device, a fan for this purpose. The injected gas stream preferably has a temperature of from 5 ° C to 65 ° C, preferably from 10 ° C to 40 ° C. The material fluid can be extruded at a temperature of 75 ° C to 160 ° C. Preferably, the gas gap has a lower temperature than that of the extruded material fluid. In particular, a gas flow in the gas gap is conducted at a lower temperature than the extruded material fluid.

Possible lengths of the gas gap, ie the distance between extrusion openings and coagulation bath, or containers for it, such as a trough, are preferably between 10 mm and 200 mm, in particular between 15 mm and 100 mm, or between 20 mm and 80 mm. Preferably, it is at least 15 mm. The gas in the gas gap is preferably air. The gas stream is preferably an air stream. Other inert gases are also possible. An inert gas is a gas which does not react chemically with the fluid filaments in the gas gap, and preferably also with the solidification medium, such as water or a dilute NMMO in water solution or other solvent constituents, depending on the extrusion medium used.

In wet spinning, the treatment zone consists essentially of liquid containers, liquid funnels or liquid gutters. The exiting from the spinneret extrudates are directly introduced into the spinning bath liquid for precipitation and / or cooling. The moist (precipitated and / or cooled) extrudates are fed through wash baths and / or through a gas or air space to the extractor.

In dry-wet spinning, the treatment zone consists essentially of a gas or air gap and downstream liquid containers, liquid funnels or liquid channels. The extrudates emerging from the extrusion openings pass through a gas gap and subsequently a coagulation bath, also called spin bath. The moist (precipitated and / or cooled) extrudates are fed through one or more wash baths and / or through a gas or air space to the extractor.

In the wet or dry-wet spinning process, turbulence and turbulence occur at higher speeds due to displacement and drag processes between coagulation bath fluid and extrudates. In addition, there is the risk of dry running at the points of contact between the extrudate and deflector at deflection with rigid deflections. The risk of dry running becomes greater the higher the take-off speed is and the more strongly the extrudate curtains or bundles thereof are pressed against the deflection device.

Preferably, the extrusion orifices are arranged in an elongated shape to form the extruded filaments in a geometry that is favorable for deflection and bundling during the deflection. The longitudinal direction of the arrangement of the extrusion openings therefore preferably also corresponds to a longitudinal direction of the deflection device. Therefore, this longitudinal direction of the deflection device preferably corresponds to a deflection axis (or follows several deflection axes in the case of curved deflection devices). Possible shapes of the arrangement of the extrusion openings are rectangular shape, a curved shape, ring or ring segment shape. The elongate shape may have a length to width ratio of from 100: 1 to 2: 1, preferably from 60: 1 to 5: 1, or from 40: 1 to 10: 1.

The extrusion openings preferably have a diameter of 30 μm to 200 μm, preferably of 50 μm to 150 μm or of 60 μm to 100 μm. This can be used for textiles (woven and non-wovens) produce suitable filament.

Preferably, the extrusion throughput is adjusted so that at the given take-off speed, a fiber fineness of the single fibers of 1.3 dtex +/- 50%, preferably +/- 25% or +/- 10%. The extrusion throughput can be adjusted by the pressure of the extruded mass, ie the cellulose solution. Possible pressures are for example 5 to 100 bar, preferably 8 to 40 bar.

Depending on formula 1 or independently thereof, the extrusion openings may be arranged along a length LL, the deflection width L being at least 70% according to this invention characteristic. , preferably at least 80% or even at least 90%, of the length is LL. The deflection width may also be equal to the length LL or even greater, such as 110% of the length LL or more. L _outside is preferably at least 1%, at least 3%, preferably at least 5% or even at least 10%, of the length LL. For bundling purposes, L _{outside is} preferably at most 50% of the length LL. All method parameters and device settings according to the invention can be combined with one another. For example, a particularly preferred combination is a take-off speed v of 40 m / min to 150 m / min and a load factor Q of 4 to 13 or 5 to 12. Of course, all values described herein are also possible in these ranges or outside. Examples:
The liquid treatment zone in the dry-wet spinning process can be designed in various ways, some variants are based on the FIGS. 1 . 2a . 2 B . 2c . 3a and 3b described. Experimental parameters and results are given in Table 1:
In Fig. 1 a first embodiment of the liquid treatment zone is shown as a spinning cone. In this variant, the spinning bath liquid is fed via a feed point (1) into a funnel-shaped container (6). The funnel-shaped container (6) has a bottom opening at the lower end. Via a bundling device (2) inserted into the bottom opening, part of the supplied spinning bath is discharged together with the extrudates (4) which are passed through the spinning hopper from top to bottom. Via an overflow edge (3), the excess part of the spinning bath is removed. The overflow edge (3) also serves to adjust the air gap (7). The extrudates emerging from the spinneret (5) are bundled vertically downwards and discharged out of the spinning funnel via a bundling device (2). The cross section of the bundling device (2) can be round, oval, polygonal or slot-shaped.

From the normal distance (H) between the nozzle outlet (5) and bundling device (2) and the given geometric relationships of the nozzle (5) results in a deflection angle (B). The deflection width (L) is that portion of the deflection device on which the extrudates actually abut and be deflected or bundled. In a torus-shaped bundling device (2), the deflection width (L) results from the product of bundling diameter (D) and the circle number (3.1415...). The deflection angle (B) results from the selected geometric relationships. The minimum required deflection width (L) is calculated using formula 1.

In Fig. 2a . 2 B . 2c . 3a and 3b For example, a liquid treatment zone is shown as a spinneret. In these variants, the spinning bath liquid (coagulation liquid) is fed via an entry point (1) into an arbitrarily shaped trough-shaped container (8). Over an overflow edge (3), the liquid is discharged from the container again. The overflow edge (3) also serves to adjust the air gap (7). Inside the spinning trough (8) a deflection device (2) and / or optionally a bundling device is mounted. The extrudates (4) emerging from the spinneret (5) are introduced vertically downwards into the sump (8). At the deflection device (2) located in the spin bath, the extrudates (4) are deflected, if necessary also bundled, led upwards out of the spinning bath and fed to the further treatment steps. The deflecting or bundling device may be round, oval or polygonal in cross-section. By way of example, a deflection device can also be a cage or bar roller consisting of a plurality of bars. A deflecting roller with ribs arranged transversely to the extrudate conveying direction is also possible. According to a further embodiment, the deflecting device (2) can also be configured concave in the axial direction in order to effect bundling in addition to the deflection of the extrudates (4) to form an extrudate strand. As in the spin bath liquid rotating elements inevitably to spin bath turbulence and in another consequence lead to winders, tears and other disorders, deflection devices in the spinning bath are generally preferably designed as a rigid deflection devices.

The normal distance (H) between the nozzle outlet (5) and the bundling device (2) is set such that the nozzle take-off angle results in a value of less than 45 °, less than 30 °, less than 15 ° or preferably less than 10 °. This measure ensures that the extrudates can be removed gently and with little deflection from the nozzle channel. Depending on the normal distance (H) and the nozzle take-off angle, the deflection angle (B) arises given geometric conditions. The deflection width (L) is that length portion of the deflection device on which the extrudates directly abut and be deflected or bundled, with a curved (concave) deflection device, this is accordingly the stretched length of the occupied by the extrudate line of contact. The deflection angle (B) results from the selected geometric relationships. The minimum deflection width (L) is calculated using formula 1.

Fig. 2a shows a spinneret system, combined with an arrangement of the extrusion openings (extruder, spinneret) in a rectangular shape. Typical for the sump system with rectangular nozzle are rather small deflection angles (B) with a large deflection width (L).

Fig. 2b shows a spinneret system combined with an extrusion opening arrangement in ring form. In contrast to the system with rectangular nozzle ( Fig. 2a ) are disadvantageous in this embodiment. The nozzle extraction angle is opposite to the rectangular nozzle design Fig. 2a much larger, whereby a gentle deduction from the nozzle channel is no longer given. In particular, with large annular nozzle diameters, it is therefore necessary to increase the normal distance (H) between the nozzle and deflection significantly. Since with large ring nozzles the required normal distance (H) can well exceed 1 meter, the manual accessibility to the deflection device is heavier, moreover, the strong frictional forces between the extrudates and the coagulation bath have a negative effect on the total tension in the filament bundle. Another disadvantage of the design Fig. 2b is the requirement that in an annular nozzle in the spinning bath not only deflected, but also must be bundled in order to provide equal conditions as possible for all annularly arranged extrudates can. For the bathtub system with ring nozzle and centric bundling in the spin bath are typically small deflection angle (B) with small deflection width (L).

Fig. 2c shows a spinneret system combined with a spinneret in annular form, wherein the deflection of the annular extrudate curtain via a toroidal deflection device with deflection angle (B ') takes place and the deflected Extrudatvorhang along the central axis of the annular nozzle is guided vertically upwards from the spinning bath. Above the annular nozzle and thus outside the spinning bath, the extrudate curtain can be bundled in an advantageously large deflection angle B. The bundling or deflection takes place outside the spinning bath liquid, the bundling or deflection can also be realized with free-rotating rollers, whereby no sliding friction A further embodiment for the bundling above the ring spinning nozzle is, similar to the spinning funnel, to provide a toroidal bundling device and, if appropriate, to install a freely rotating deflection roller downstream Fig. 2c can many disadvantages which a system after Fig. 2b has to be eliminated. The nozzle take-off angle (A) is opposite to the ring nozzle design Fig. 2b greatly reduced, whereby a gentle deduction is given from the nozzle. Even with large nozzles, the normal distance (H) can be kept low, allowing manual accessibility to the deflection device. A bundling of the extrudate curtain in the spinning bath is not needed. Typical for the tub system with annular nozzle and toroidal deflection device in the spin bath are rather small deflection angles (B) with a large deflection width (L).

Fig. 3a shows a comparative example in the form of a spinning trough system, combined with a rectangular nozzle, wherein the extrudate curtain is deflected twice in the spinning trough. The, seen in the direction of production, the first deflection is analogous to the execution of Fig. 2a designed, the second deflection is used for a further change of direction and at the same time for bundling the extrudate curtain to an extrudate strand. For the illustrated deflection system with bundling typical are rather moderate deflection angle (B) with small deflection width (L) due to the bundling. Due to the strong bundling, it was necessary to choose a high load factor of 20. The spinning behavior turned out to be unsatisfactory.

Fig. 3b shows a spinneret system as in Fig. 3a However, the second deflection was dimensioned based on a much smaller load number (no or little bundling). Due to the greater length (L) of the deflecting device could in contrast to the execution of Fig. 3a a very satisfactory spinning behavior can be achieved.

After exiting the coagulation bath, the bundles are brought to a common extraction and washing by means of a take-off unit and a washing station, which can also be combined with one another. The first extractor after the bath provides the withdrawal speed of the threads when spinning. Fig. 4 shows a possible deduction, here 7 rollers are shown schematically. Any number of rolls adapted to the system can be used, eg 1 to 60 are common. At the rollers here the bundles are deflected at an angle B of 0 ° to 150 °. Preferably, the width of the filament bundles according to formula 1 is also adhered to here, wherein Q may be higher than in the coagulation bath, for example 40 to 300. All rolls can be driven or only some of the rolls. All driven rollers can be driven together or separately. With simultaneous washing, a different speed is recommended, at least the rotation of the roll surface, for rolls of the same size and the rotational speed of the rolls per se, since during washing the filaments lose solvent and shrink. The shrinking process should be imaged by decreasing speeds so that the filaments do not tear. Non-driven rollers may be free-rotating rollers. With driven rollers, stiction occurs between the filaments and the roller; For non-driven rollers, a sliding friction between filament and roller.

To prepare the cellulose solution, an ionic solution was prepared as an alternative and in parallel to the lyocell method with NMMO / water as the solvent. The used cellulose of the eucalyptus pulp type was suspended in deionized water. After complete suspension of the cellulose fibers in the water, the excess water was separated by filtration and pressed the resulting pulp cake to a solids concentration of about 50% cellulose. Following dewatering, the pulp cake was fed through a needle roller and shredder for defibration. The resulting, finely divided wet cellulose was in continuous flow into the aqueous ionic liquid 1-N-butyl-3-methylimidazolium chloride (BMIMCl), entered to create the pre-mix. Ring layer mixers and / or turbulent mixers are the suitable apparatuses for this purpose.

The mixture of water, cellulose and BMIMCl was added in the further process sequence, for the preparation of the cellulose solution, in a continuous vertical kneader type Reactotherm from Buss-SMS-Canzler GmbH. Similar equipment of the kneading and reactor technology as well as all types of extruder, high-viscosity thin layer, stirred tank and / or disk reactor can be used for cellulose solution preparation individually or in combination in different reactor zones and process stages. In this vertical Reactotherm kneader, the cellulose solution could be continuously produced without lumps by intensive mixing and kneading action. Treatment times in the individual reactor zones from 20 to 80 minutes resulted in complete dissolution of the cellulose.

For safe process control, further stabilizers were added to the aqueous mixture of ionic liquid and cellulose, before the transfer from the pre-mix to the cellulose solution, to stabilize the solvent and to prevent cellulose degradation. The continuously prepared pre-mix was transferred under application of temperature and vacuum (vacuum), and under shear in a highly viscoelastic solution. The temperatures used in the individual process stages varied between 85 ° C and 150 ° C, with the removal of excess water at reduced pressure between 10 and 150 mbar. The applied shear rates moved to homogenize the pre-mix in the range of 20 to 200 rpm while maintaining the adjusted shear rate and torque. This ensured that the cellulose dissolved in the ionic liquid. The high-viscosity cellulose solution thus obtained was subjected to additional process steps such as degassing and filtration before spinning. To adjust the corresponding cellulose pulp quality, the solution was additionally supplied via one or more, the process stages adapted, high-viscosity heat exchangers of the type Sulzer SMR / SMXL. These serve in addition to the temperature setting, especially for setting the desired spinning viscosity, and the degree of polymerization of cellulose. These heat exchangers therefore served for efficient temperature adjustment, Such as cooling or heating of the high-viscosity cellulose solution, as they enabled effective mixing and a controlled heat transfer.

The spinning of the cellulose solution to filaments, as well as the further processing was carried out according to the invention, wherein the spinning solution was fed by spin pump a heated spin pack consisting of spinneret filter, distribution plates and the spinneret. The spinning temperatures were in the range of 85 ° C-150 ° C, preferably in the range of 95 ° C-115 ° C. Care was taken after the solution preparation step for short residence times at elevated temperatures in the process system to adjust the cellulose solution to the processing speed and the unwanted degradation of the cellulose.

The spinning process used is described in the invention and is commonly referred to as a dry-wet spinning process wherein the adjustable height-adjustable air gap is disposed between the spinneret and the aqueous coagulation bath containing the ionic liquid. The gas stream supplied to the air gap and thus through the filaments is conditioned and may be conditioned air or another inert spinning gas. According to the invention, the filaments are passed through the coagulation bath, discharged from the bath and fed to the further treatment as described above. The parameters and product properties of the experiments with BMIMCl and NMMO as solvents are summarized in Table 2. <b> Table 2: </ b> Ionic liquid N-methyl morpholine N-oxide (BMIMCI) (NMMO) cellulose eucalyptus eucalyptus DP Cuoaxam [-] 535 646 α cellulose content [%] 95.2 94.8 carboxyl [Mol / g] 17 27 carbonyl group [Mol / g] 23 29 ash content [%] 0.4 0.2 Whiteness WCIE [-] 82 84 fiber data Solids content cellulose in ionic liquid [%] 13.27 12.8 DP cuprammonium [-] 521 584 Zero shear viscosity at 85 ° C [Pas] 39720 19,250 Dope temperature [° C] 102 95 Nozzle hole diameter [Μ] 90 90 spinning pressure [bar] 37 27 air gap [Mm] 43 38 spinning bath [° C] 20 18 fiber fineness [Dtex] 1.63 1.71 Tensile strength conditioned [CN / tex] 51.2 41.0 Stretching conditioned [%] 13.9 15.2 wet modulus [CN / tex] 297 185 Naßscheuerzahl [U] 54 38

Claims (15)

A process for producing cellulosic solid filaments from a fluid of the cellulose by extruding the fluid through a plurality of extrusion orifices to form fluid filaments, preferably passing the fluid filaments through a gas gap and solidifying the filaments in a coagulation bath, wherein the filaments are bundled in the coagulation bath and bundled be deflected to be deducted from the coagulation above the Koagulationsbadniveau, characterized in that the bundle of filaments on a deflection device occupies a deflection width L, which according to the formula: $$\mathrm{L}>\left(\mathrm{2}\times \mathrm{LZ}\times \cos \left(\mathrm{B}/\mathrm{2}\right)\times {\mathrm{v}}^{\mathrm{2}.\mathrm{5}}\right)/\left(\mathrm{10}\times {{\mathrm{c}}_{\mathrm{cell}}}^{\mathrm{0}.\mathrm{5}}\times \mathrm{Q}\right)$$

L is the deflection width of the bundle in mm, LZ the number of extrusion openings, B the deflection angle calculated from 180 ° minus the angle of wrap of the filaments around the deflection device in degrees, v the withdrawal speed of the filaments in meters per second, c _cell the cellulose concentration of the extruded fluid in mass% and Q is a dimensionless load number, where Q is 15 or less. Apparatus for carrying out a method according to claim 1, comprising an extrusion plate with a plurality of extrusion orifices, a collection tank for a coagulation bath, preferably with a gas gap between the extrusion openings and the collecting tank, a deflection device in the collecting tank for deflecting a filament bundle from the collecting tank, and a bundling apparatus which a deflection width L of the filament bundle on the deflection device, the filament bundle occupying a deflection width L on the deflection device, which has the formula: $$\mathrm{L}>\left(\mathrm{2}\times \mathrm{LZ}\times \cos \left(\mathrm{B}/\mathrm{2}\right)\times {\mathrm{v}}^{\mathrm{2}.\mathrm{5}}\right)/\left(\mathrm{10}\times {{\mathrm{c}}_{\mathrm{cell}}}^{\mathrm{0}.\mathrm{5}}\times \mathrm{Q}\right)$$

satisfies, wherein L, LZ, B, v, c _cell and Q have the meaning given in claim 1, Q is 15 or less and v is at least 35 m / min. A method or apparatus according to claim 1 or 2, characterized in that Q is 12 or less, preferably 8 or less or 5 or less and / or that Q is 2 or greater, preferably 3 or greater or 4, or 5 or greater, in particular preferably wherein Q is 2 to 15 or more preferably 4 to 12. A method or apparatus according to any one of claims 1 to 3, characterized in that the number of extrusion openings LZ is 2000 or more, preferably 5000 or more or 10000 or more, and / or that LZ is 500000 or less, preferably 100000 or less or 50,000 or smaller. Method or device according to one of claims 1 to 4, characterized in that the deflection angle B is an angle of 10 ° to 90 °, preferably 20 ° to 60 ° or 25 ° to 45 °. Method or device according to one of claims 1 to 5, characterized in that the withdrawal speed v is 36 m / min or more, preferably 40 m / min or more or 45 m / min or 50 m / min or more, and / or 200 m / min or less or 150 m / min or less. Method or device according to one of claims 1 to 6, characterized in that the cellulose concentration of the extruded fluid c _{cell is} 4% to 23%, preferably 6% to 20%, in particular 8% to 18% or 10% to 16% ( % all in% by mass) and / or wherein the extruded fluid contains cellulose, NMMO and water or cellulose, an organic cationic solvent and water. Method or device according to one of claims 1 to 7, characterized in that blown in the gas gap, a gas flow or in the apparatus, a fan is provided for this purpose, wherein preferably the gas stream has a temperature of 5 ° C to 65 ° C, preferably from 10 ° C to 40 ° C. Method or device according to one of claims 1 to 8, characterized in that the extrusion openings are arranged in an elongate shape, preferably in a rectangular, curved, ring or ring segment shape, preferably wherein the elongate shape has a length to width ratio of 100: 1 to 2: 1, preferably from 60: 1 to 5: 1 or from 40: 1 to 10: 1. A method or device according to any one of claims 1 to 9, characterized by the further steps of removing the coagulated filaments from the coagulation bath, deflecting the filaments outside the coagulation bath, with or without further bundling with other coagulated filaments, feeding the filaments to a draw-off, and or a drawing device, as well as continuing to a filament receiving unit, washing and drying the filaments, wherein preferably further steps are optionally provided: softening, dyeing, crosslinking, ultrasonic treatment, cutting, and / or winding, in each case of the filaments / extrudates. Method or device according to one of claims 1 to 10, characterized in that the extrusion openings have a diameter of 30 .mu.m to 200 .mu.m, preferably from 50 .mu.m to 150 .mu.m or from 60 .mu.m to 100 .mu.m. Method or device according to one of claims 1 to 11, characterized in that the extrusion openings are arranged on a length LL and the deflection width L is at least 80%, preferably at least 90%, of the length LL. A process for producing cellulose solid filaments from a fluid of the cellulose by extruding the fluid through a plurality of extrusion orifices, thereby forming fluid filaments, preferably passing the fluid filaments through a gas gap and solidifying the filaments in a coagulation bath, wherein the filaments are bundled in the coagulation bath and deflected as a bundle in order to be withdrawn from the coagulation bath above the coagulation bath level, characterized in that the extrusion openings are arranged along a length LL and the bundle of filaments on a deflection device occupies a deflection width L which is at least 80% of the length LL. Apparatus for carrying out a method according to claim 13, comprising an extrusion plate with a plurality of extrusion openings, a collecting container for a coagulation bath, preferably a gas gap between the extrusion openings and the collecting container, a deflection device in the collecting container for deflecting a filament bundle from the collecting container, and a bundling device which causes a deflection width L of the filament bundle on the deflection device, characterized in that the extrusion openings are arranged on a length LL and the bundle of filaments on the deflection device a deflection width L of at least 80% of the length LL occupies. Method or device according to one of claims 1 to 14, characterized in that the bundle of filaments on a deflection outside the coagulation bath occupies a deflection width L _outside , which according to the formula: $${\mathrm{L}}_{\mathrm{Outside}}>\left(\mathrm{2}\times \mathrm{LZ}\times \cos \left(\mathrm{B}/\mathrm{2}\right)\times {\mathrm{v}}^{\mathrm{2}.\mathrm{5}}\right)/\left(\mathrm{10}\times {{\mathrm{c}}_{\mathrm{cell}}}^{\mathrm{0}.\mathrm{5}}\times \mathrm{Q}\right)$$

is controlled, wherein L _outside the Umlenkbreite of the beam in mm, LZ, the number of extrusion orifices, B the deflection angle calculated from 180 ° minus the winding angle of the filaments around the deflection in degrees, v is the velocity of the filaments in meters per second, c _Cell Cellulose concentration of the extruded fluid in mass% and Q is a dimensionless load number, where Q is 300 or less;
preferably at least during a first deflection after the filaments exit the coagulation bath and / or at least during a diversion in a withdrawal unit.

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