Title of Invention

A PROCESS AND APPARATUS FOR PRODUCING CELLULOSE FIBERS OR FILAMENTS

Abstract

The present invention relates to a method for the production of cellulose fibres or cellulose filament yams from pulp by the dry and wet extrusion method with aqueous amine oxides as solvent, whereby, a) a dispersion of pulp and aqueous amine oxide is transformed into a homogeneous solution with a relaxation time in the range 0.3-90 s at 85°C by water removal and shearing, b) the solution is introduced into a spinning packet with at least one spinning nozzle (6) by means of a spinning solution feed (3), c) the solution is passed through a filter (4), a support plate (1) a flow chamber (5.1) and into at least one spinning capillary of at least one spinning nozzle (6) in the spinning packet, d) the solution strands moulded into capillaries are fed through a non-precipitating medium with further drawing and blown with a gas stream approximately perpendicularly to the filament nmning direction, just before entry into the precipitation bath, the cellulose precipitates in the precipitation bath and e) the cellulose fibres are withdrawn from the precipitating bath by directional change and the fibres drawn off The invention further relates to a device for the production of cellulose fibres or filament yams by the wet and dry extrusion method with aqueous amine oxides as solvent, comprising a solution feed (3) and a spinning packet with a sieve filter packing (4), support plate (1), flow chamber (5.1) and spinning nozzle(s) (6), working according to said method.

Full Text

Method and device for production of cellulose fibres and cellulose filament yarns [Description] This invention relates to a process for producing cellulose fibers or filament yarns from chemical pulp by the dry-jet wet spinning process using aqueous amine oxides as a solvent, which comprises a) a dispersion of chemical pulp and aqueous amine oxide being converted at elevated temperature by water withdrawal and shearing into a homogeneous solution having a relaxation time in the range 0.3 - 90 s at 85oC, b) the solution being fed through a spinning solution feed means to a spin pack having at least one spinneret die, c) the solution passing in the spin pack through a filter, a support plate, an inflow chamber and at least one spinning capillary of at least one spinneret die, d) the solution jets which have been formed into filaments being passed with further stretching through a noncoagulating medium, shortly before entry into the coagulation bath being subjected to a gas stream at approximately right angles to the filament transport direction, the cellulose being precipitated in the coagulation bath, and e) the cellulose filaments being separated from the coagulation bath at the end of the coagulation bath trip by deflection and the filaments being withdrawn. This invention further relates to apparatus for producing cellulose fibers or filament yarns from chemical pulp by the dry-jet wet-spinning process using aqueous amine oxides as a solvent, consisting of a solution feed means and a spin pack having sieve filter pack, support plate, inflow chamber and spinneret die (s), that operates according to the process of this invention. [Prior art] US 4 24 6 221 and US 4 416 698 disclose dissolving cellulose in water-containing amine oxides, shaping in spinning capillaries under low shear, stretching the solution jets in a large air gap, precipitating the cellulose by a spin bath containing aqueous amine oxide and withdrawing the cellulose filaments over a godet. US 5 417 909 describes a process which includes shaping the solution in the spinning capillaries under high shear, stretching the solution jets in a short air gap, precipitating the cellulose and the filaments or sheet of filaments being gathered via a spinning funnel and transported cocurrently. EP 0 430 926, EP 0 494 852, EP 0 756 025 and WO 94/28 210 describe spin packs having round and rectangular dies having different spinning capillary geometries and arrangements. EP 0 662 166 discloses a precious metal spinning die insert in a rotationally symmetrical arrangement and that the filament sheet formed is immediately after leaving the spinning capillaries cooled by an air stream supplied rotationally symmetrically via an impingement plate. This arrangement will meritably give rise to undefined cooling of the precious metal spinneret die insert. EP 0 584 318, EP 0 671 492, EP 0 795 052, WO 94/28 218 and WO 96/21 758 describe a wide range of forms of treating the filament sheet in the gap between spinneret die and coagulation bath with air of differing water content. All spin packs are heated electrically or by a jacket filled with heating fluid. The dies or die inserts arranged in special steel spinneret plates receive the heat by conduction via the spinneret plate and it in turn receives its heat via the spin pack. With this customary form of heating, the temperature distribution across the spinneret plate and the spinneret dies is likely to be considerable. WO 99/47733 and DE 100 19 660, then, describe apparatus to vary the temperature of the cellulose solution across the capillary cross section by means of a gaseous heating fluid. In DE 100 19 660, individual thin-walled spinning capillaries made from stainless steel are surrounded by an annular gap through which hot air having a temperature above that of the spinning solution, for example at 150 oC or more, flows around the spinning capillaries and in the process creates a flow profile which is said to lead to fibers of high loop breaking length and low fibrillation. Disadvantages of this arrangement are the comparatively large amount of space required for each spinning capillary and the relatively costly and inconvenient engineering. DE 100 25 230 and DE 100 25 231 teach obtaining fibers of high loop breaking strength and low fibrillation by maintaining the average heat flow and/or the average acceleration across the air gap width at a certain level- It is further known for fiber structure and properties to be modified by certain aftertreatment processes, such as treatment with crosslinking agents (EP 0 783 602, EP 0 796 358), with 10 - 18 % aqueous sodium hydroxide solution (WO 97/45 574) or with alkanol, -diol, -triol in at least one washing bath (WO 97/25 462). These processes come at significantly increased cost and inconvenience. DE 199 54 152 Al discloses a process for producing cellulose fibers and cellulose filament yarns by the dry-jet wet-spinning process. The issue yet unresolved with this process is that of improved temperature management and temperature consistency. The published prior art reveals that the form of temperature management is of decisive importance when spinning cellulose solutions by the dry-jet wet-spinning process. [Object clause] It is an object of the present invention to create a process and apparatus which, through improved temperature management and consistency, makes it possible to spin cellulose solutions into fibers having improved properties, especially with regard to uniformity, wet breaking strength and fibrillation characteristics. The uniformity of fiber properties is advantageously evaluated via the coefficient of variation of fineness and of breaking strength respectively, and fibrillation characteristics are advantageously evaluated by measuring the wet abrasion resistance. The method for determining the wet abrasion resistance has been extensively described in the literature [Mieck K.P.; Langner H. Nechwatal A. "Melliand Textilberichte" 74 (1993) p. 945 'Lenzinger Berichte" 74 (1994) pp. 61-68; and Mieck K.P. Nicolai A; Nechwatal A.; "Lenzinger Berichte" 76 (1997) p. 103]. The wet abrasion resistance is measured in terms of the number of cycles required of a roll of defined geometry which is covered with a woven cellulose fabric to cause the breakage of a moistened fiber which is under a defined tension. Lyocell fibers generally achieve a level of 5 - 35 cycles. The focus of the present invention is not primarily on maintaining a certain temperature, but, on the contrary, on minimizing deviations from a target value not only across the cross section of the solution feed means but also between and within dies and spinning capillaries. The temperature dependence of the viscosity of cellulose solutions is given by a logarithmic function of the form lηη = InKn + EA / RT where η0 = zero shear viscosity; Kη = constant; EA = activation energy; R = general gas constant and T = temperature in K. The dependence of viscosity on temperature is extremely large for cellulose solutions, whereas their thermal conductivity is substantially equal to that of an insulator. Take a solution containing 12 % of softwood pulp cellulose or 14 % of eucalyptus pulp cellulose. The temperature dependence of the zero shear viscosity is given by the experimentally determined relation Inη0 = " 16.7565 + 9105 1/T and Inη0 = - 18.0464 + 10055 1/T respectively. The zero shear viscosity of the solution is 8 400 ± 600 Pas or 34 100 ± 2 750 Pas respectively for a spinning temperature of for example 80 ± 1oC. Considering that it is the elongational viscosity which is of primary importance for structure development in the gap and that this elongational viscosity is at least 3 times the size of the zero shear viscosity, the high demands placed on temperature management during spinning are underlined. The significant change in viscosity with temperature is somewhat eclipsed by the dependence on the shear rate during flow or on the elongation rate during deformation in the gap. Cellulose solutions have an extremely viscoelastic behavior and the relaxation times after shearing are distinctly above those of other polymers. For this reason, not only the temperature but also the shear and elongation rate as well as the relaxation time, have to be taken into account in the field of transporting and shaping cellulose solutions. The relaxation times of cellulose solutions can be calculated from the oscillographically recorded deformation curves of storage and loss moduli over shear rate (the determination is extensively described by Ch. Michels, Das Papier, 1998 / 1 pages 3-8). The chemical constitution of a cellulose solution requires that the apparatus be fabricated from special steel or precious metals. Precious metals are only used in the exceptional case of thimble dies. But special steels, possessing comparatively low thermal conductivity, can lead to appreciable problems with the heating/temperature control of the cellulose solution during transportation and during deformation in the spin pack. The object is achieved in relation to the process mentioned at the beginning (Fig. 1 + 2) when the solution in step b) flows through the optionally temperature-controllable solution feed means (3) which is constructed as a heat exchanger, in step c) initially passes at a shear rate of y which is constructed as a heat exchanger and has flow channels (1-1) and subsequently through the inflow chamber (5.1), formed of support plate (1) and intermediate ring (5) , at a residence time of tv > [s] and thereafter is formed in at least one spinning capillary of at least one thimble spinneret die (6) which is provided with a separate die temperature control means (2) including insulation (2.1) and a temperature which is below that of the cellulose solution in the interior of the thimble die to form a filament or filament bundle and in step d) these are shortly before entry into the coagulation bath subjected to the flow of a slow sheetlike gas stream blown against them at a substantially right angle at a rate of 2 - 20 1/min per thimble die (6) . Transportation of the solution through the heat exchanger solution feed means (3) and support plate (1) in conjunction with the inflow chamber (5.1) ensures that all the spinning capillaries of the thimble die or dies come into contact with a completely relaxed solution of the same temperature and that radiant heat dissipation through the precious metal die surface can be controlled by the die temperature control means (2) with insulation (2.1). It was found that the temperature equalization via the heat exchanger support plate (1) and solution feed means (3) in combination with the complete relaxation of the solution in the inflow chamber (5.1) leads to a significant improvement in the uniformity of fiber properties. This is reflected in distinctly lower coefficients of variation for fiber properties, for example the breaking strength from 15 - 25 to 3 - 10 %. It has further been found that, surprisingly, the filament tension in the gap between spinning capillary exit and coagulation bath entry can be varied within wide limits by the die temperature control means (2), especially when the temperature of the die temperature control means (2) is not more than that of the spinning dope. The experimentally accessible filament tension is primarily dictated by the product of elongational viscosity and elongation rate. The elongation rate can be determined from the relation where Vg is the extrusion speedy a is the length of the gap between spinneret die exit and coagulation bath entry and SV3 is the spin-stretch ratio in the gap. On the assumption that the elongational tension in the gap is substantially identical to the filament tension (friction being neglected), the elongational viscosity follows from the relation where p is the density of the solution in q/cm3, a is the air gap in cm, σ.F is the filament tension in cN/tex and V3 is the takeoff speed in m/min. Fig. 6 depicts the change in elongational viscosity over the elongation rate for the spinning of a solution according to Fig. 2 having a cellulose concentration of 12.4 % and a dope temperature of 80 oC for various temperatures (28, 43, 64 and 86 oC) of the die temperature control means. The result is a completely unexpected behavior, since the elongational viscosity should show a decrease with increasing elongational rate similar to that of the shear viscosity with increasing shear rate. It was found that as the elongational viscosity rises the dry and wet breaking strength, the breaking force ratio and the wet abrasion resistance increases. When spinning solutions of cotton 1inters chemical pulps it was possible to spin fibers having a dry/wet breaking force ratio of 100 %. The process of the present invention further permits a distinct widening of the viscosity range in which the cellulose solutions are readily spinnable, and the spinning at comparatively lower temperatures or higher cellulose concentrations. The object is further achieved according to the present invention with regard to the apparatus mentioned at the beginning when the solution feed means (3) is formed from a tube packed with one or more optionally heatable bodies of high thermal conductivity which are pervaded by flow channels, when the support plate (1) consists of a material of high thermal conductivity, the dimensioning of the flow channels (1.1) satisfies the relation of the solution at 85oC at the maximum frequency of the relaxation time spectrum, and the thimble die(s) are surrounded by a separate die temperature control means (2) with insulation (2.1). In a further, preferred embodiment of the solution feed means, it consists of an ordinary steel tube containing one or more inserted thin-walled special steel tubes for transporting the solution and where the interspaces have been filled up with cast aluminum for heat exchange and for pressure stabilization-Fig. 4 depicts the die temperature control means for a filament spinning position. The thimble spinneret die (6) is surrounded by the die temperature control means (2) consisting of a material of high thermal conductivity with clamping gap (2.3) and resistance coil (2.2). The die temperature control means is slightly conical (as shown in (6.1), Fig. 4) in order that a secure seating for the die temperature control means on the thimble die may be ensured. The thickness of the die temperature control means is in general 3-6 mm. The resistance heating is operated using a low voltage current, preferably 24 V. Fig. 3 depicts the die temperature control means (2) where the thimble spinneret dies (6) are arranged in rows. Temperature control is effected via the heating cartridges (2.2). This arrangement can be used not only for staple fibers but also for filament yarns, as depicted in Fig. 2. Fig. 5 finally shows an arrangement of the die temperature control means (2) featuring heating cartridges (2.2) and thimble spinneret dies (6) which is preferred for staple fibers. The circular blow nozzle (12) is arranged similarly to Fig. 2 and blows radially against the filament bundles shortly before entry into the coagulation bath. The diameter of the thimble spinneret dies is preferably 12 and 20 mm for textile filament yarns and preferably 20 and 35 mm for industrial filament yarns and staple fibers. The spinning capillary density is between 15 and 4 00 spinning capillaries/cm2, depending on the end product. The spinning capillaries themselves are not subject to special requirements. In correspondence with the wall thickness of the thimble dies, which is preferably 0.5 mm, the overall length of the spinning capillaries is likewise 0.5 mm. The ratio of capillary inlet and outlet cross section is preferably in the range from 2:1 to 10:1, the transition is preferably continuous, the cylindrical spinning capillary outlet has a diameter D of preferably 80 - 140 pm and the L/D ratio is preferably 1. The heat exchangers which are surrounded by the cellulose solution, i.e. solution feed means and support plate, are preferably fabricated from nickelized or anodically oxidized aluminum. Copper and brass, even after surface refinement, are unsuitable for lack of chemical resistance. Even after most careful surface refinement, contact with the cellulose solution is observed to lead to the formation of copper ions, which can lead to an unacceptable safety risk. The die temperature control means, by contrast, can be made not only of surface-refined aluminum but also without problems from copper or brass, preferably in surface-refined form. The process of the present invention and the apparatus will now be more particularly described with reference to illustrative embodiments. Example 1 A suspension of spruce sulfite pulp and aqueous N-methyl-morpholine N-oxide (NMMO) in a vertical kneader is stripped of sufficient water under vacuum, elevated temperature and shearing until a homogeneous solution consisting of 12.4 % of cellulose (cuoxam DP 530), 76.2 % of NMMO and 11.4 % of water is formed. Zero shear viscosity is 7 600 Pas and relaxation time 5.2 s at 85oC (Fig. 8). The spin head, equipped with jacket heating, contains selectively a support plate composed of special steel or nickelized aluminum which is 64 mm in diameter and 10 mm in thickness and on which 40 flow channels 3 mm in diameter are arranged in 3 rows of holes. A ring between support plate and die plate for receiving 2 thimble dies formed an inflow chamber 23 cm3 in volume. The thimble dies possessed a total of 60 spinning capillaries having an outlet diameter of 130 μm, in the ratio of inlet to outlet cross-sectional area being 2.7. They were selectively equippable with 2 die temperature control means composed of brass with resistance heating (24 V) as per Fig. 4. The spinning of 1.2 and 1.6 dtex fiber at a takeoff speed of 100 m/min was carried out in variant A by using a support plate composed of special steel, in variant B by using a heat distributor composed of nickelized aluminum and in variant C by using a heat distributor and die temperature control means. The temperature of the dope in the inflow space and that of the die temperature control means was 8 6 oC. The blown air rate was 5 1/min per die. The experimental data and the properties of the spun fibers are given in table 1. Parameter (Table 1) 1.6 dtex 1.3 dtex Volume flow rate cm3/min 6.00 4.50 Shear rate s-1 0.94 0.71 A suspension of cotton linters pulp in aqueous NMMO is converted into a solution consisting of 12.0 % of cellulose (cuoxam DP 579) , 76.5 % NMMO and 11.5 % of water similarly to example 1. Zero shear viscosity was 6 630 Pas and relaxation time 1.7 s at 85oC (compare Fig. 7)- The spinning arrangement corresponded essentially to variant C in example 1 except that spinning was accomplished using a thimble die (25 x 20 x 9.5 X 0.5 rnrn) having 750 spinning capillaries 90 pm in outlet diameter and an inlet to outlet cross section ratio of 6.25. Fiber of 1.2 dtex was spun at a dope temperature of 7 6 ^C and various temperatures for the die temperature control means (43, 60 and 86 QC) . Spinning this solution at dope temperatures of less than 80 ^C is impossible without additional die heating. Shortly before entry into the coagulation bath, the filament bundle had an 8 1/min air stream blown against it from a slot nozzle. The experimental data and fiber parameters are given in table 2. Example 3 A suspension consisting of aqueous amine oxide and very finely divided eucalyptus pulp was converted into a homogeneous solution of 11.8 % of cellulose (cuoxam DP 605), 76.9 % of NMMO and 11.3 % of water similarly to example 1. Zero shear viscosity was 6 800 Pas and relaxation time 18.6 s at 85°C (cf. Fig. 9). Spinning was accomplished using a rectangular spin pack which was fluid heated via a jacket and had 4 rowed thimble spinneret dies (25 x 20 x 9.5 x 0.5 mm) each featuring 200 spinning capillaries having an outlet diameter of 140 m. L/D ratio of cylindrical portion - 1. The ratio of entry to exit cross section was 5.0. A continuous 150 g/min of spinning solution at a dope temperature of 80°C was conveyed by the solution feed means to the spinneret die filter, passed through a rectangular hole plate (50 x 150 x 10 mm) composed of nickelized aluminum having 500 bores 0.25 cm in diameter, an inflow chamber having a volume of 90 cm2, were formed into 4 filament yarns each of 200 individual filaments, stretched through a 35 mm air gap, quenched through a slot nozzle with 4 1 of air/min per die, the cellulose was precipitated in the coagulation bath, taken off at 200 m/min, washed, dried, spin finished and wound up as a filament yarn. The 4 thimble dies in the spin pack were surrounded by a die heating means which was constructed as a plate (cf. Fig. 3) and featured heating rods. The die temperature control means, adjusted to 60°C, consisted of nickelized brass and was insulated from the die plate by a Teflon sheet 0.5 mm in thickness. Broken filaments are produced continually without die temperature control means. The results are given in table 3 • Parameter (Table 3) 4 X 250 dtex (200) Volume flow rate cm3/min 132 Shear rate s-1 2.9 Residence time s 2.2 .. X85°C Extrusion speed m/min 10.7 Overall draw ratio 9.7 Fineness dtex 200 X 1.25 Coefficient of variation g, 0 0.3 Tenacity cN/tex 56.9 Coefficient of variation a. 0 6.5 Wet abrasion resistance cycles 105 -1 1} measured on the individual filaments Example 4 A LIST Diskotherm B ® kneader is continuously fed with 1 110 g/min of a suspension consisting of 11.9 % of cellulose, 66.1 % of NMMO and 22 % of water, stripped of 135 g/min of water under vacuum, elevated temperature and shearing and, via a twin-screw conveyor, exited of 975 g/min of homogeneous solution having a dope temperature of 90°C and consisting of 13.5 % of cellulose, 75.2 % of NMMO and 11.3 % of water and, via solution feed means constructed as a "shell-and-tube heat exchanger" having 9 thin-walled special steel tubes 1.5 cm in diameter and otherwise packed out with cast aluminum fed to the spinning position while at the same time cooling to 85 °C. The relaxation time spectrum of the solution corresponds to Fig. 10, the relaxation time is 84.7 s. The spin pack is constructed as a ring (cf. Fig. 5), 9 thimble dies (43 x 35 x 9.5 x 0.5 mm) and each of its 2 500 spinning capillaries are arranged in a circle. The exit diameter of the spinning capillaries is 90 μm (L/D - 1). The ratio of entry to exit cross section is 4:1. The die temperature control means is formed by a goldized copper plate which is heated by heating cartridges to 70 oC and was insulated by a silicone layer from the die plate. The support plate constructed as a ring is composed of anodically oxidized aluminum and contains 1 750 flow channels 0.3 cm in diameter. The volume flow rate of 13.9 cmVs results in a shear rate of 3.0 s-1. The inflow chamber having a volume of 1 670 cm3 led to a 85° C residence time of 1.4 xA^ After the solution was formed into 9x2 500 filaments, these passed under stretching and quenching via a round-slot nozzle at 15 1 of air/min per die through an air gap and the coagulation bath of 2.5 cm and 17 cm respectively, were combined to form a tow, washed, cut into staples and aftertreated. The fiber test values are given in table 4. [List of reference numerals] (1) Support plate (2) Die temperature control means (2.1) Insulation (die temperature control means) (2.2) Heating cartridges (2.3) Clamping gap (3) Solution feed means (4) Sieve filter packing (5) Intermediate ring (5.1) Inflow chamber (6) Thimble die(s) (6.1) Conical execution Die temperature control means (7) Seals (8) Spin pack holder (9) Spin bath (10) Filament yarn/fiber tow (11) Fiber guide element (12) Blow nozzle [Accompanying drawings] Number of accompanying drawings; [10] Fig. 1 Spin liead Fig. 2 Spinning arrangement for multiple spinning Fig. 3 Die temperature control means with rowed arrangement of thimble spinneret dies Fig. 4 Die temperature control means for a filament spinning position Fig.5 Die temperature control means with radial arrangement of thimble spinneret dies Fig. 6 Change in elongational viscosity over elongational rate at different die temperatures Fig. 7 Relaxation spectrum for example 2 Fig, 8 Relaxation spectrum for example 1 Fig. 9 Relaxation spectrum for example 3 Fig. 10 Relaxation spectrum for example 4 WE CLAIM: 1. A process for producing cellulose fibers or filaments from chemical pulp by the dry-jet wet- spinning process using aqueous N-methylmorpholine N-oxide as a solvent, which comprises : a) a dispersion of chemical pulp and aqueous N-methylmorpholine N-oxide being converted at elevated temperature by water withdrawal and shearing into a homogeneous solution having a relaxation time λm in the range 0.3 - 90 s at 85°C, b) the solution being fed through a spinning solution feed means to a spin pack having at least one spinneret die, c) the solution passing in the spin pack through a filter, a support plate, an inflow chamber and at least one spinning capillary of at least one spinneret die, d) the solution jets which have been formed into filaments being passed with further stretching through a noncoagulating medium, shortly before entry into the coagulation bath being subjected to a gas stream at approximately right angles to the filament transport direction, the cellulose being precipitated in the coagulation bath, and e) the cellulose filaments being separated from the coagulation bath at the end of the coagulation bath trip by deflection and the filaments being withdrawn, characterized in that the solution in step b) flows through the solution feed means (3) which is constructed as a heat exchanger, in step c) initially passes at a shear rate of γ <. through a support plate which is constructed as heat exchanger and has flow channels> and subsequently through the inflow chamber (5.1) at a residence time of and thereafter is formed in at least one spinning capillary of at least one thimble spinneret die which is provided with a separate die temperature control means (2) comprising insulation (2.1) and a temperature which is below that of the cellulose solution in the interior of the thimble die (6) to form a filament or filament bundle and in step d) these are shortly before entry into the coagulation bath subjected to the flow of a slow sheetlike gas stream blown against them at a right angle at a rate of 2 - 20 1/mm per thimble die. 2. The process as claimed in claim 1, wherein chemical pulps from wood, cotton linters or other annual plants are converted into homogeneous solutions having a relaxation time 3. The process as claimed in claim 1 or 2, wherein the shear rate during passage through the heat exchanger is in the range 0.1 - 3 s-1 4. The process as claimed in claim 1, wherein the temperature of the spinning solution is in the range 60 to 100oC and the temperature of the die temperature control means is in the range 30 to 95oC. 5. The process as claimed in claim 1, wherein the gas stream in step d) is formed by atmospheric air. 6. The process as claimed in claim 1, wherein the filament bundle is subjected to an air stream at 8 - 10 1/mm per die over a length of bath in step d). 7. An apparatus for producing cellulose fibers or filament yams from chemical pulp by the dry-jet wet- spinning process using aqueous N-methylmorpholine N-oxide as a solvent, consisting of the solution feed means (3) and a spin pack comprising the sieve filter packing (4), the support plate (1) with flow channels (1.1), the intermediate ring (5) with inflow chamber (5.1), at least one thimble die (6), the seals (7) and the spin pack holder (8) according to processes as per claims 1 to 6, wherein the solution feed means (3) is formed from a tube packed with one or more bodies of high thermal conductivity which are pervaded by flow channels, in that the support plate (1) consists of a material of high thermal conductivity, the dimensioning of the flow channels (1.1) satisfies y is the shear rate in l/s, V is the volume flow rate in cm3/s, D is the diameter of the flow channels in cm and N is the number of channels, and the thimble die(s) are surrounded by a separate die temperature control means (2) with insulation (2.1). 8. The apparatus as claimed in claim 7, wherein the solution feed means (3) formed from a tube packed with one or more bodies pervaded by flow channels is temperature controllable. 9. The apparatus as claimed in claim 7 or 8, wherein the bodies of high thermal conductivity which are pervaded by flow channels and which are situated in solution feed means (3) consist of anodically oxidized or nickelized aluminum. 10. The apparatus as claimed in claim 7, wherein the bodies of high thermal conductivity which are pervaded by flow channels and are situated in the solution feed means (3) can be temperature controlled by heating cartridges or resistance heating. 1L The apparatus as claimed in claim 7, wherein the support plate (1) constructed as a heat exchanger consists of of anodically oxidized or nickelized aluminum with or without addition of alloying constituents. 12. The apparatus as claimed in claim 7 , wherein the thimble dies (6) consist of a 70/30 gold/platinum alloy. 13. The apparatus as claimed in claim 7, wherein the ratio of spinning capillary inlet and outlet cross sections is between 2:1 and 10:1. 14. The apparatus as claimed in claim 7, wherein the thimble die (6) is annularly surrounded by the die temperature control means (2) and thermally separated from the die pack by an air gap (2.1). 15. The apparatus as claimed in claim 7, wherein the insulation (2.1) takes the form of a thin layer of silicone rubber or Teflon. 16. The apparatus as claimed in claim 7, wherein the die temperature control means (2) consists of a metal ring of high thermal conductivity, electrical resistance coil (2.2) and clamping gap (2.3). 17. The apparatus as claimed in claim 7, wherein the die temperature control means (2) is formed from a metal plate of high thermal conductivity and heating cartridges (2.2) when the thimble dies (6) are arranged in rows. 18. The apparatus as claimed in claim 7, wherein the die temperature control means (2) is formed by a metal ring having heating cartridges (2.2) when the thimble dies (6) are arranged in a circle. 19. The apparatus as claimed in claim 7 and 16 to 18, wherein the metal ring or plate of the die temperature control means (2) consists of aluminum, copper, brass or precious metal. 20. The apparatus as claimed in claim 7, wherein the surface of the metal plate of the die temperature control means (2) is anodically oxidized, nickelized, chromized, silverized or goldized.

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