EP0807698A2 - Procédé et dispositif pour la préparation d'une structure fibrillaire à base de dérivés de cellulose - Google Patents

Procédé et dispositif pour la préparation d'une structure fibrillaire à base de dérivés de cellulose Download PDF

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Publication number
EP0807698A2
EP0807698A2 EP97106492A EP97106492A EP0807698A2 EP 0807698 A2 EP0807698 A2 EP 0807698A2 EP 97106492 A EP97106492 A EP 97106492A EP 97106492 A EP97106492 A EP 97106492A EP 0807698 A2 EP0807698 A2 EP 0807698A2
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EP
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Prior art keywords
dope
solvent
fibrets
precipitation
cellulose
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EP97106492A
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German (de)
English (en)
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EP0807698B1 (fr
EP0807698A3 (fr
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Heinz-Joachim Müller
Rüdiger Leibnitz
Udo Holzki
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Pall Filtersystems GmbH
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SEITZ-FILTER-WERKE GmbH
Seitz Filter Werke GmbH and Co
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/40—Formation of filaments, threads, or the like by applying a shearing force to a dispersion or solution of filament formable polymers, e.g. by stirring
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/18—Formation of filaments, threads, or the like by means of rotating spinnerets
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
    • D01F2/24—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives

Definitions

  • the invention relates to a method for producing fibrets according to the preamble of claim 1 and a device according to the preamble of claim 21.
  • Fibrets are understood in the following as very fine fibers, which are characterized by very fine fiber diameters and thus by a very high mass-specific surface. Fibrets are typically produced by means of a precipitation process or by extrusion, in which case precipitation is usually integrated as a sub-process. Fibrets are partly present in the fiber composite or fiber network as a result of the production.
  • the diameters of the individual fibers are generally less than 5 ⁇ m, mostly less than 1 ⁇ m.
  • the dimensions of the fiber networks which are referred to as agglomerates and which can be varied over a wide range by the conditions during production and by further processing steps, are up to 1 mm. However, agglomerate sizes of less than 200 ⁇ m are aimed for. With the dimensions mentioned, mass-specific surfaces of over 20 m 2 / g are achieved.
  • the fibrets are mainly used in depth filters for liquid filtration, whereby these filters are also used to prove the quality of the fibrets.
  • depth filters For optimal operation of depth filters, it is crucial to realize small pore sizes with high porosity. In terms of filtration technology, this results in high separation achieved low differential pressures.
  • Embedding the fibrets in fiber networks also has the advantage over particulate material and shortened staple fibers that the fibers are very tightly integrated in the filter and detachments during the filtration can be largely excluded.
  • the fiber structure in the agglomerate composite gives the filters high strength and flexibility, which is advantageous for pleating.
  • fibrets are not limited to depth filters for liquid filtration.
  • nonwovens for air filtration for example, fibrets can replace the glass fibers, the harmful effects of which are known when they enter the lungs.
  • fibrets can be used as optical brighteners in the paper industry. Small amounts of remaining solvent can cause the fibers to fuse during drying, so that e.g. in nonwovens the strength can be increased significantly.
  • Fibrets can generally be made from a variety of materials. The only limits are set by the solvent and the viscosity of the solution. As a result of their advantages in the choice of the solvent, fibrets made of cellulose esters, in particular cellulose acetate, with mass-specific surfaces over 20 m 2 / g have mainly been presented in the literature. For use in depth filters for liquid filtration, fibrets made from cellulose acetate also have the advantage that, together with the pulp used as matrix material largely achieved material homogeneity is achieved. This ensures problem-free disposal. Compared to the currently preferred diatomaceous earth, perlites and / or metal oxides, the advantages of the very low ion emission and the complete biodegradability must be emphasized.
  • a solution (dope) is usually prepared from a cellulose ester and a suitable solvent.
  • the non-solvent for the cellulose ester which is completely miscible with the solvent, can be present in proportions which do not significantly affect the dissolving behavior of the cellulose ester in the solvent.
  • This solution is usually precipitated under the action of shear forces in a non-solvent or precipitant for the cellulose ester, which is completely miscible with the solvent.
  • the resulting fibrets dampen the turbulence to a great extent, since the distance between the extrusion opening and the wall of 1.6 mm is only insignificantly larger than the maximum agglomerate size of 1 mm, so that solids contents exceeding 1% by mass ( % By weight) cannot therefore be exceeded after the precipitation. Since the turbulence is increasingly dependent on the solids content, the stirring arrangement has poor part-load behavior. Furthermore, the exit velocity of the dope is influenced by the centrifugal forces because the extrusion nozzles are arranged in the rotating disk. This also affects the precipitation conditions.
  • Two-component nozzle systems as are described in US Pat. No. 4,192,838, US Pat. No. 5,071,599 and US Pat. No. 5,175,276, and the T-pipe systems which are explained, for example, in US Pat. No. 3,961,007, implement a similar principle.
  • the precipitation is carried out in two-stream nozzles in cocurrent, in the case of T-pipe systems in countercurrent.
  • the nozzle diameter - usually> 2.5 mm - must be designed to be large enough to prevent the solution from failing at the nozzle opening.
  • the nozzle diameter is therefore 20,000 times larger than the required one Fiber diameter.
  • the countercurrent process in the T-pipe systems is the more effective variant with regard to vortex formation and thus shear field formation.
  • the precipitation bath flow is braked very strongly, so that the precipitation conditions vary to a large extent.
  • the formation of coarser fibers especially in the case of solids contents after the precipitation of approximately 1% by mass, cannot be avoided.
  • these dimensions can only be influenced to a minor extent by workup steps after the precipitation.
  • the partial load and clogging behavior of the counterflow variant is also to be assessed negatively.
  • a disadvantage of the known production process is that large amounts of solvent have to be circulated.
  • US Pat. No. 5,071,599 and US Pat. No. 5,175,276 mention 8 kg of solvent, for example acetone, for the production of 1 kg of fibrets.
  • US Pat. No. 3,842,007 and US Pat. No. 3,961,007 for example, require between 20 and 80 kg or 33 kg of solvents, such as acetone, 1,4-dioxane or methyl acetate, for 1 kg of fibrets.
  • the amount of solvent remaining in the fibrets is too high for further processing in most applications.
  • the fibret surface is not fully hardened due to the solvent contained in the solution.
  • the network structure is partially lost when pressure is applied, which leads to clumping at high pressures. For this reason, it is usually filtered under the action of shear forces, with solids contents of at most 4% by mass being achieved with specific surfaces of over 20 m 2 / g.
  • fibrets to solvent are in a ratio of approx. 1: 1, otherwise the solvent predominates.
  • the object of the invention is to provide a method and a device which allows a more economical production of the fibrets with better quality.
  • the invention is based on the finding that working up the constituents of the coagulation bath separated from the fibrets is only sensible and economical if the coagulant used for the coagulation bath may have as high a proportion of solvent as possible and if at the same time it is permitted that the separated solvent proportion , which is reused for the preparation of the dope, may still have a non-solvent content.
  • Contamination of the Solvent due to the non-solvent and vice versa has its limit where the dope prepared with the prepared solvent can no longer be processed. Too high a proportion of non-solvent can lead to premature precipitation on the one hand and to an excessive viscosity of the dope on the other.
  • dispersing devices are e.g. distributed by the company Ystral under the name “dispersing machine” and by the company IKA Maschinenbau under the name “Dispax-Reaktor". These devices usually contain two to six shear rings, which are preferably designed alternately as stators and rotors. The rotors reach speeds of up to 12,000 revolutions per minute, so that basic flow velocities of up to preferably 100 m / sec can be achieved in the precipitation bath. These known dispersing devices with their high peripheral speeds are usually used for emulsifying, suspending, homogenizing and dissolving dispersions. Although the use of discontinuous dispersion systems is also possible within the scope of the invention, the advantages of continuous dispersion systems lie in the reliable guarantee of a uniform product quality.
  • the suspension formed from dope and precipitant is accelerated and decelerated alternately at least once, preferably at least twice, a high degree of turbulence is maintained over a long distance, so that a dope with high viscosity can be processed.
  • the suspension is alternately preferably subjected to a radial and a transverse flow.
  • the dope is preferably introduced into the precipitant through stationary nozzles, means for generating a flow being moved past their outlet openings.
  • the dope emerging from the nozzles is detected and deducted very quickly, so that nozzle clogging cannot occur even at higher viscosities.
  • the fibrets are already largely homogenized by the alternating acceleration and deceleration, so that under certain circumstances. a subsequent homogenization treatment can be dispensed with. This is obviously due to the fact that a high mean turbulence can be maintained over a long distance, and that during the entire residence time in the dispersing device, which is usually between 0.03 and 0.5 sec.
  • the turbulence itself is only slightly dampened by the fibrets that form, since the turbulence is generated by rotating machine parts and not by a turbulent flowing medium.
  • This has the further advantage that the partial load behavior of the entire arrangement is very good. This means that in large areas the fibret quality is independent of the total throughput of the precipitation bath and the dope and of their relationship to one another.
  • the dope is preferably prepared with cellulose esters or cellulose ethers.
  • Cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate, benzyl cellulose or ethyl cellulose and other suitable cellulose derivatives or mixtures of these materials are preferred.
  • a cellulose diacetate with an acetyl value between 54 and 56% is preferably used.
  • the proportion of cellulose derivatives in the dope is preferably 3-20% by mass. Lower concentrations are usually not economically attractive, larger proportions require too high a viscosity.
  • the proportion of solvent must also be adjusted. Acetone can be used as the solvent.
  • Acetic acid methyl acetate, methyl ethyl ketone, 1,4-dioxane, acetaldehyde, ethyl acetate, tetrahydrofuran or methyl isopropyl ketone or mixtures of the solvents mentioned can be used.
  • the solvent acetone is particularly preferred.
  • Preferred non-solvents for the cellulose ester are water, ethanol or methanol, the proportion of which in the dope can be up to 40% by mass.
  • the maximum content of non-solvents based on the ratio of solvent to cellulose derivative depends on the precipitation point. The higher the non-solvent content in the dope, the faster the precipitation point is reached.
  • the maximum salary is determined by the precipitation point, which i.a. is temperature-dependent.
  • a non-solvent content of 2-20% by mass below the concentration of the non-solvent at the respective precipitation point is preferred.
  • US 5,071,599 and US 5,175,276, which describe two-component nozzle systems only up to 20% by weight of non-solvent are permitted in the dope, so that this proportion in the system cellulose acetate, acetone and water is between 8.5% and 21% below Precipitation point.
  • the ratio of solvent to cellulose derivative should also be minimized.
  • the ratio can be a minimum of 4.4.
  • Lower ratios usually cause the viscosity of the dope to be too high, which has a negative effect on the fibret fineness in the known processes. Solves for example, cellulose diacetate in acetone in a mass ratio of 1: 3, a gel-like consistency is obtained.
  • the viscosity can be reduced by adding water as the non-solvent. In this regard, it is desirable to add water to just below the precipitation point.
  • the prior art processes are unable to produce fibrets with an acetone: water mass ratio of, for example, 2.8 and a non-solvent content of up to 2% by mass below the precipitation point in the dope.
  • the viscosity is still too high despite the addition of water.
  • the main advantage is that higher viscosities of the dope can be processed with satisfactory results.
  • solvent: cellulose derivative ratios between 4.4: 1 and 2.8: 1 can be achieved without the quality of the fibrets deteriorating. Particularly good results could be achieved if the solvent acetone, cellulose ester cellulose diacetate and non-solvent water were used.
  • a reduction in the ratio of acetone: cellulose diacetate from 4.4: 1 to 2.8: 1 means that 36% by mass less solvent has to be used to produce a predetermined amount of fibrets, which considerably reduces the production costs of the fibrets.
  • the temperature of the dope is largely uncritical for the process. Good results have been obtained at room temperature. To reduce the A higher temperature can be selected for the viscosity of the solution, up to precipitation at overpressure and temperatures above 100 ° C. however, the ambient temperature is preferred as the most economical variant.
  • the two or three components of the dope are mixed in a suitable manner until a homogeneous solution is obtained. This solution is then optionally fed to the dispersing device via a filter.
  • the volume flow of the precipitant in the precipitation bath is preferably adjusted so that the fibret content in the precipitation bath is between 0.1 and 2.5% by mass. Differences in the fibret quality could not be determined even with a high fibret content. At concentrations between 2.5 and 3.5% by mass, precipitation is still carried out without clogging of the extrusion nozzles, but there are drawbacks to the fibret fineness and fibrethomogeneity. A range of 1-2.5% by mass is preferred for economic reasons.
  • the process according to the invention is thus significantly better than the processes according to the prior art, according to which the precipitation is only possible at concentrations between 0.1 and 1% by mass.
  • the methods according to the prior art must work with a large excess of the precipitation medium compared to the dope, in particular at higher viscosities of the dope, in order to generate sufficient turbulence.
  • a minimum ratio of precipitation bath: dope of 11: 1 has been achieved with the two-component nozzle systems according to US Pat. No. 4,192,838 and US Pat. No. 5,071,599 and US Pat. No. 5,175,276.
  • the process according to the invention permits the production of fibrets at a precipitation bath: dope ratio of 10: 1 to 2.5: 1. This has the following advantages:
  • the concentration of the cellulose derivative in the dope can be chosen to be low.
  • acetone content for the acetone-cellulose diacetate-water system in the coagulation bath may not exceed 15% by mass.
  • the acetone present in the suspension causes the solidification of the fibers to extend over a longer period.
  • the surfaces of the fibrets that have not yet completely solidified can stick together and form lumps without a porous fibret structure.
  • the shear effect is high enough to separate such lumps until the fibers have completely solidified.
  • the longer solidification time of the fibrets also contributes to finer fibrillation and associated with a higher surface area, because shear forces act on the entire solidification time, intensifying the fibrillation.
  • acetone contents in the precipitation bath of up to 25% by mass are possible.
  • the device for producing the fibrets provides that the at least one nozzle, through which the dope is introduced into the precipitant, is arranged in a dispersing device having a rotor and stator, which has at least two toothed rings, of which at least one toothed ring is part of the rotor of the Is dispersing device and that the dispersing device has a feed line for the precipitant.
  • Precipitation bath and dope are combined in the dispersing device to achieve the precipitation.
  • the precipitation bath flows through the dispersing machine, as is known from homogenizing and dispersing tasks.
  • the feed line for the precipitant preferably encloses the feed line for the dope.
  • the nozzle is preferably arranged in the interior of the dispersing device and aligned radially outward on the innermost ring gear.
  • the first is in the flow direction of the precipitation bath Sprocket part of the rotor, followed by a sprocket of a stator, etc.
  • the distance between sprocket and nozzle is small to allow the actual precipitation in the zone of the shear field, which is generated by the teeth moving in front of the nozzle opening.
  • the distance can be between 0.01 and 5 mm, preferably 0.01-0.1 mm. It is also possible to equip the first ring gear in the direction of flow of the precipitation bath with nozzles for adding the dope.
  • the nozzle diameter can be selected in large areas because this parameter has only a minor influence on the quality of the fibrets in the intended area.
  • a nozzle diameter between 5 and 10 mm is preferred. However, smaller nozzle diameters are possible. Since no blockages of the nozzles occur during the use of the dispersing device, the use of larger nozzles, although possible from the point of view of the fibret quality, is also not necessary. If the volume flow from precipitant to dope is low or the total volume flow is high, it is advisable to divide the dope flow over several nozzles.
  • These nozzles are preferably arranged symmetrically within the innermost ring gear. If, for example, three nozzles are provided, they are arranged in a star shape.
  • the feed line to the nozzles is preferably located in the center of the dispersing device.
  • the precipitation agent is also introduced centrally into the dispersing device. This is ensured by the fact that the feed line of the precipitant preferably encloses the feed line of the dope.
  • fibrets develop very quickly after the dope has been introduced into the precipitation bath.
  • the development time is of the order of 0.001 - 0.5 seconds.
  • the fibret morphology should then be determined.
  • an outer shell first forms, since the concentration bales in the Scherfeld first reaches the concentration of non-solvent required for the precipitation.
  • the solvent must diffuse outwards and / or the non-solvent inwards through this shell. A time which is greater than the specified precipitation time therefore passes again until the core has hardened.
  • the fibers Since the outer morphology has already developed in this time period, the fibers, despite the soft inner core, have a turbulence-inhibiting effect to such an extent that the fibers can no longer be divided.
  • a dispersing device it is possible to cut fibers with a soft inner core by means of the high shear effect applied by the rotors and therefore to increase the fineness of the fibrets.
  • the dispersing device also has a positive effect on the agglomerate size of the fibrets.
  • agglomerate sizes of up to 1 mm can also be achieved.
  • FIG. 1 shows the plant for the production of fibrets.
  • the raw material for example cellulose diacetate
  • the dope is fed via the feed line 1 to a dope preparation tank 2, to which solvent 31 is fed from the treatment plant 26 via the line 31.
  • the dope is fed to a dispersing device 40 via a double line 3, where the precipitation is carried out.
  • the precipitant is prepared in a precipitation bath 8 into which non-solvent, preferably water, is fed via line 27 from the processing plant 26.
  • the precipitant used is introduced into the dispersing device 40 via a precipitation bath feed line 9, where the precipitant is combined with the dope. This will be explained in connection with FIG. 2.
  • the precipitation bath suspension with the fibrets produced is fed to the distillation plant 12 via the precipitation bath discharge line 13.
  • Steam is fed to the distillation plant 12 via a steam feed line 15, and the separated solvent is first fed via a heat exchanger 16 to the treatment plant 26 via the solvent return line 17, where the treatment of the solvent takes place in such a way that it then returns to the dope preparation tank 2 or the precipitation bath preparation tank 8 can be used.
  • the fibrets are fed to a high-pressure homogenizer 20 via the discharge line 19. From there, the fibrets go into a stacking tank 22 and further into a drum filter 24, where the fibrets are concentrated to the desired final concentration, the precipitation bath also being fed to the treatment plant 26 via the return line 25.
  • the fibrets prepared in this way are fed via the fibret derivation 23 for further processing.
  • the treated solvent which can contain a certain proportion of non-solvent and the non-solvent, which in turn can contain a portion of solvent, is introduced into tanks 2 and 8 via lines 27 and 31, respectively.
  • the dispersing device 40 is shown in vertical section.
  • the precipitant is fed into the interior of the dispersing device 40 via the curved feed line 9.
  • the dope feed line 3 is located within the feed line 9 and is enclosed by it, so that both the dope and the precipitant can be introduced centrally into the dispersing device 40.
  • the double line 3 branches inside the housing 41 and merges into the nozzles 46 and 47, which are arranged in a star shape together with the nozzles 48 and 49, which is shown in FIG.
  • the nozzles extend outward in the radial direction and end at a short distance in front of the innermost ring gear 50, which is part of the rotor 44.
  • This rotor 44 is driven by a drive shaft 65 which extends downward from the housing 41 and is driven by a motor (not shown). Sealing to the housing 41 takes place via a mechanical seal 64.
  • the rotor 44 which has a base plate 10, comprises, in addition to the first ring gear 50, a further ring gear (third ring gear) 52 spaced apart therefrom. Between the two ring gears 50 and 52 there is the second ring gear 51, which belongs to the stator 43.
  • the stator 43 which has an annular base plate 11, is arranged above the nozzles 46-49, so that the second ring gear 51 extends downward and is fastened to the housing 41.
  • a further stator 45 which has the outer or fourth ring gear 53, is arranged below the rotor.
  • the precipitation bath feed line 9 Since the precipitation bath feed line 9 is sealed against the stator 43, the precipitant is fed centrally and flows around the nozzles 46 to 49.
  • the dope which is fed through the double line 3 exits the nozzles 46 to 49 in the radial direction and into the shear field one, which extends through the ring gears 50-53 into the outer region 14.
  • Dope and precipitant will be first gripped by the ring gear 50 and accelerated. Due to the radial direction of flow of dope and precipitant, which is superimposed on the cross-flow, the dope or the fibrets being formed leave the zone 60 in the radial direction through the gaps 54 between the teeth 55 of the first ring gear 50, whereby dope and precipitant are delayed .
  • the liquid then passes into a further zone 61 between the ring gear 50 and the ring gear 51, where the liquid is accelerated again.
  • This ring gear 51 since it belongs to the stator, is stationary.
  • the fibrets successively reach the further zones 62 and 63 between the ring gears 51 and 52 or 52 and 53, where accelerations and decelerations alternate.
  • the fibrets are discharged together with the precipitation bath in the form of a suspension via the discharge pipe 13. Fibrets were produced with this device and are described in the examples below.
  • FIG. 4 shows schematically the course of the average degree of turbulence of the dope / precipitant mixture as a function of the distance from the nozzle according to the prior art (US 4,047,862 - curve I) and according to the invention (curve II).
  • a minimum degree of turbulence which is characterized by straight line III, must be exceeded for the production of fibrets. Below curve III, the turbulence is too low for the precipitation, so that the desired fineness of the fibrets is not achieved.
  • the degree of turbulence required for fibrin production is only reached shortly behind the nozzles, and then drops exponentially, so that only a relatively short distance is available for fibrin production.
  • the shear field according to the invention extends in a dispersing device according to FIGS. 2 and 3 over approximately 14 mm (distance from ring gear 50 to ring gear 53), the minimum degree of turbulence required for fibrin production being exceeded and remaining constant after exiting the nozzle.
  • the curve II drops steeply only when the outer region (see FIG. 2) 14 is reached. While working according to US 4,047,863 with circumferential speeds of about 30 m / sec, the rotational speed of the rotor of the dispersing device is 41 m / sec in this example.
  • 480 g of a cellulose diacetate (CA) from Eastman Chemical Company (type CA 398-3) are dissolved in 3840 g of acetone and 480 g of water.
  • the resulting dope thus contains 10 Ma% CA, 10 Ma% water and 80 Ma% acetone.
  • the ratio of acetone to water is 8.
  • the dope is passed into the precipitation bath at ambient temperature with a mass flow of 3 kg / min through a four-jet nozzle, each with a diameter of 5 mm and the ends of which are 0.10 mm from the inner rotor headed. Water is also used as the precipitation medium at ambient temperature and enters the precipitation chamber with a mass flow of 34.5 kg / min.
  • the mass flows of precipitation bath and dope are in a ratio of 11.5 to 1.
  • the dispersing machine is equipped with four sprockets of the "fine" specification (see Table 1).
  • the precipitation takes place at a speed of 12,000 min -1 .
  • CA fibrets are present at a concentration of 0.8% by mass.
  • Acetone is 6.5% by weight.
  • the values mentioned and the values for the following tests are compared in Table 2.
  • the acetone is removed by open distillation at ambient pressure. After the acetone has been removed, the fibrets are homogenized in one stage using a high-pressure homogenizer from APV GAULIN, type LAB 60, at a pressure of 150 bar.
  • the fibrets are concentrated for storage with a nutsche.
  • a filter cake with a solids concentration of 8.6% by mass is formed.
  • the experiment was carried out analogously to experiment 1, except that the precipitation bath mass flow was reduced to 15.75 kg / min. There was a ratio of the mass flows of precipitation bath to dope of 5.25 and a concentration of the fibrets after precipitation of 1.6 Ma% (at 12.8 Ma% acetone). High-pressure homogenization was dispensed with.
  • the experiment was carried out analogously to experiment 1, except that the precipitation bath mass flow was reduced to 12 kg / min. There was a ratio of the mass flows of precipitation bath to dope of 4.0 and a concentration of the fibrets after precipitation of 2.0 mass% (at 16.0 mass% acetone). High-pressure homogenization was dispensed with.
  • the experiment was carried out analogously to experiment 1, except that a mass ratio of acetone to CA of 5 was set. With a mass flow ratio of precipitation bath to dope of 7.2 there are 1.7 Ma% fibrets with 8.5 Ma% acetone after the precipitation.
  • the experiment was carried out analogously to experiment 1, except that a mass ratio of acetone to CA of 3.5 was set. With a mass flow ratio of precipitation bath to dope of 9.9, 1.65% by mass of fibrets with 5.80% by weight of acetone are present after the precipitation.
  • Experiment 10 was carried out analogously to experiment 6, except that water of up to 28% by mass was additionally added to the dope. 5% by mass of acetone were present in the precipitation bath. After precipitation, the fibrets had a concentration of 1.5% by mass with an acetone concentration of 9.8% by mass.
  • Each of the samples had specific surfaces above 20 m 2 / g and individual fiber dimensions, preferably below 1 ⁇ m. However, further parameters such as homogeneity, accessibility of the fiber networks for the flow etc. are decisive for the filtration.
  • the layers had a basis weight of 1350 g / m 2 .
  • the layers were tested with a test suspension of 0.5% by weight of raw raw cane sugar in water.
  • the test area was 100 cm 2 .
  • the throughput was determined after 30 min at a differential pressure of 1 bar. After a filtration period of 15 minutes, the turbidity measurement was sampled to determine the separation effect.
  • the initial turbidity for all layers in the test series carried out in parallel was approximately 2.40 TE / F.
  • Each of the filter layers produced with the described fibrets was tested in three runs. Table 3 shows the mean values.
  • the fibrets of sample 9 are positive.
  • the addition of acetone to the precipitation medium results in better fibrillation.
  • the geometry of the sprockets used in the examined area has no significant influence on the quality of the fibrets.
  • FIG. 5 shows the dependence of the maximum possible water content on the concentration of the cellulose acetate in the dope (both in% by mass) at a temperature of 20 ° C.
  • the acetone content is obtained by subtracting the respective CA and water concentrations from 100% by mass.
  • the diagram shows that the greatest difference to the prior art is at 5% by mass of cellulose acetate and the smallest at 15% by mass of cellulose acetate.
  • Maximum water content according to the invention 5.0 Ma% cellulose acetate 37.7 mass% water 57.3 mass% acetone State-of-the-art maximum water content 5.0 Ma% cellulose acetate 19.0 mass% water 76.0 mass% acetone Difference in water content compared to the prior art 18.7 Ma% (based on dope) 15% by mass of cellulose acetate: Falling point concentration: 15.0% by mass of cellulose acetate 25.5 mass% water 59.5 mass% acetone Maximum water content according to the invention 15.0% by mass of cellulose acetate 23.5 mass% water 61.5 mass% acetone State-of-the-art maximum water content 15.0% by mass of cellulose acetate 17.0% water 68.0 mass% ace
  • Figure 5 clearly shows the advantages of the invention, which consist in the fact that the cellulose acetate portion can be chosen much larger (see expanded area according to the invention) and that the water portion can be significantly higher, which, as described above, has decisive advantages in the Process management (elimination of the filtration stage) and the process costs (preparation with less effort).

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Artificial Filaments (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
EP97106492A 1996-04-23 1997-04-18 Procédé et dispositif pour la préparation d'une structure fibrillaire à base de dérivés de cellulose Expired - Lifetime EP0807698B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19616010A DE19616010C2 (de) 1996-04-23 1996-04-23 Verfahren und Vorrichtung zur Herstellung von Fibrets (Fibriden) aus Zellulosederivaten
DE19616010 1996-04-23

Publications (3)

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EP0807698A2 true EP0807698A2 (fr) 1997-11-19
EP0807698A3 EP0807698A3 (fr) 1998-04-08
EP0807698B1 EP0807698B1 (fr) 2002-11-06

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EP97106492A Expired - Lifetime EP0807698B1 (fr) 1996-04-23 1997-04-18 Procédé et dispositif pour la préparation d'une structure fibrillaire à base de dérivés de cellulose

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US (1) US5868973A (fr)
EP (1) EP0807698B1 (fr)
AU (1) AU757068B2 (fr)
DE (2) DE19616010C2 (fr)

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DE19959532C1 (de) * 1999-12-10 2001-10-04 Seitz Schenk Filtersystems Gmb Verfahren und Vorrichtung zur Herstellung von filtrationsaktiven Fasern
MXPA06003599A (es) * 2003-10-01 2006-06-20 Debio Rech Pharma Sa Dispositivo y metodo para producir particulas.
CN101688329B (zh) * 2007-07-11 2012-06-20 松下电器产业株式会社 精细聚合物的制造方法
CZ302503B6 (cs) 2009-12-11 2011-06-22 Contipro C A.S. Zpusob prípravy derivátu kyseliny hyaluronové oxidovaného v poloze 6 glukosaminové cásti polysacharidu selektivne na aldehyd a zpusob jeho modifikace
CZ302504B6 (cs) 2009-12-11 2011-06-22 Contipro C A.S. Derivát kyseliny hyaluronové oxidovaný v poloze 6 glukosaminové cásti polysacharidu selektivne na aldehyd, zpusob jeho prípravy a zpusob jeho modifikace
CZ2012136A3 (cs) 2012-02-28 2013-06-05 Contipro Biotech S.R.O. Deriváty na bázi kyseliny hyaluronové schopné tvorit hydrogely, zpusob jejich prípravy, hydrogely na bázi techto derivátu, zpusob jejich prípravy a pouzití
CZ304651B6 (cs) 2012-05-11 2014-08-20 Contipro Biotech S.R.O. Způsob přípravy mikrovláken, způsob výroby krytů ran, kryty ran a zařízení pro přípravu polysacharidových vláken
CZ304512B6 (cs) 2012-08-08 2014-06-11 Contipro Biotech S.R.O. Derivát kyseliny hyaluronové, způsob jeho přípravy, způsob jeho modifikace a použití
CZ304654B6 (cs) 2012-11-27 2014-08-20 Contipro Biotech S.R.O. Nanomicelární kompozice na bázi C6-C18-acylovaného hyaluronanu, způsob přípravy C6-C18-acylovaného hyaluronanu, způsob přípravy nanomicelární kompozice a stabilizované nanomicelární kompozice a použití
CZ2014150A3 (cs) 2014-03-11 2015-05-20 Contipro Biotech S.R.O. Konjugáty oligomeru kyseliny hyaluronové nebo její soli, způsob jejich přípravy a použití
CZ2014451A3 (cs) 2014-06-30 2016-01-13 Contipro Pharma A.S. Protinádorová kompozice na bázi kyseliny hyaluronové a anorganických nanočástic, způsob její přípravy a použití
CZ309295B6 (cs) 2015-03-09 2022-08-10 Contipro A.S. Samonosný, biodegradabilní film na bázi hydrofobizované kyseliny hyaluronové, způsob jeho přípravy a použití
CZ2015398A3 (cs) 2015-06-15 2017-02-08 Contipro A.S. Způsob síťování polysacharidů s využitím fotolabilních chránicích skupin
CZ306662B6 (cs) 2015-06-26 2017-04-26 Contipro A.S. Deriváty sulfatovaných polysacharidů, způsob jejich přípravy, způsob jejich modifikace a použití
CZ308106B6 (cs) 2016-06-27 2020-01-08 Contipro A.S. Nenasycené deriváty polysacharidů, způsob jejich přípravy a jejich použití
WO2024206270A2 (fr) * 2023-03-29 2024-10-03 Eastman Chemical Company Procédés de fabrication de microbilles d'ester de cellulose avec un solvant contenant de l'eau
WO2024206272A2 (fr) * 2023-03-29 2024-10-03 Eastman Chemical Company Procédés de fabrication de microbilles d'ester de cellulose avec récupération et recyclage de solvant
CN119710953A (zh) * 2024-11-28 2025-03-28 浙江理工大学 一种用于生产并列型复合微纳米纤维的离心纺喷丝器

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Also Published As

Publication number Publication date
US5868973A (en) 1999-02-09
AU1907897A (en) 1997-10-30
AU757068B2 (en) 2003-01-30
DE19616010C2 (de) 1998-07-09
EP0807698B1 (fr) 2002-11-06
DE59708645D1 (de) 2002-12-12
EP0807698A3 (fr) 1998-04-08
DE19616010A1 (de) 1997-11-06

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