Classifications

• • 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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/70—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyurethanes
• • 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
  • D01D5/04—Dry spinning methods

Definitions

• the invention relates to a method for spinning segmented polyurethane urea elastomers in dry spinning chimneys while introducing certain amounts of superheated steam.
• the process allows an extraordinary increase in the spinning performance per shaft as well as an increase in the spinning speed, in particular in the case of medium and coarse titers, at high spinning shaft temperatures and without undesired change, in some cases even with a significant improvement in the thread properties of the filament yarns obtained.
• the new process in particular also prevents tendencies of the spinning solvents to decompose at high temperatures in air (otherwise necessary for extensive spinning solvent removal at high spinning speeds) without the use of inert gases as spinning air media.
• the new process also enables the spinning of (multi) filament yarns with higher single filament titers, which contributes to improving the stability of the filament yarns against external influences and degradation influences.
• Highly elastic PU elastomer threads are mainly manufactured using wet and, in particular, dry spinning processes.
• highly viscous solutions of the elastomers in dimethylformamide or dimethylacetamide are spun through multi-hole nozzles into heated spinning shafts, to which hot air is additionally fed (cf. H. Oertel, in synthetic fibers, publisher: B. v Falkai, Verlag Chemie Weinheim 1981, pp. 180 to 190 and H. Gall / KH Wolf in Kunststoff Handbuch, Vol. 7, Polyurethane, 1983, C. Hanser Verlag, pp. 611 to 627).
• the temperature of the spinning solution, the temperature in the spinning shaft, the temperature of the additionally supplied hot air and the take-off speed, and the geometric dimensions of the spinning shafts essentially determine the drying out of the filaments with extensive removal of the solvents.
• Japanese Patent 44-896 (1969) describes a dry spinning process for glycol chain-extended polyurethane elastomers based on higher molecular weight polyesters, diisocyanates and ethylene glycol, dissolved in a mixture of methyl isobutyl ketone / DMF or tetrahydrofuran as a solvent, these polyurethanes being spun in a spinning shaft of at least 150 ° C with introduction above the spinneret from 1 to 30 m3 / h superheated steam at 150 to 400 ° C and at moderate take-off speeds (low spinning performance).
• Such threads show practically the same properties in comparison to threads spun without water vapor.
• Volatile solvents such as tetrahydrofuran are used or are also used.
• Glycol-extended polyurethane elastomers of this type cannot be spun at elevated shaft temperatures and at the same time high temperatures of gaseous spinning media; they tear off or are stretched thermoplastic with an undesirable change in the elastic properties.
• the spinning performance described by the Japanese process still remains very unsatisfactory for such glycol-extended polyurethanes.
• the object of the invention is to provide an improved dry spinning process, according to which the polyurethane urea (PUH -) elastomers, based on diamine chain extension of NCO prepolymers, are made practically completely from highly polar solvents such as dimethylformamide and especially dimethylacetamide, with high spinning performance and without the risk can be spun from decomposition of the spinning solvent at high temperatures to PUH elastomer threads, which now have only a low content of spinning solvent, have a good raw color and also have improved elastic properties compared to threads spun from hot air.
• the inventive task should be as possible without changing the existing which spinning shafts (especially their length) can be achieved.
• the invention relates to an improved dry spinning process of polyurethane elastomer fibers using superheated steam as the spinning medium, characterized in that Polyurethane urea elastomers which have been produced by diamine chain extension of NCO prepolymers, from their solutions in dimethylformamide or (preferably) dimethylacetamide via a spinneret hot at least 100 ° C at spinning solution temperatures in the nozzle of at least 100 ° C, preferably 105 to 125 ° C, in a heated spinning shaft of at least 160 ° C shaft wall temperature, for example 160 to 238 ° C, preferably 170 to 230 ° C, and in particular 175 to 225 ° C, and in the case of shaft diameters up to 28 cm at least 20 kg / h, preferably 25 to 50 kg / h, particularly preferably 30 to 45 kg / h, superheated steam of greater than 250 ° C., preferably 275 to 400 ° C., in particular 280 to 325 ° C (measured
• polyurethane urea elastomer threads can be spun with excellent economy, spinning shaft performance and quality.
• these polyurethane urea elastomer threads surprisingly do not show the sharp decrease in extensibility and undesirably high module values of the threads in comparison to the usual spinning speeds (for example of about 200 m / min), but surprisingly rather an increase in the elongation at break compared to similar spinning conditions in hot air (if such a spinning is possible at all with hot air).
• One of the causes may be the interaction between water (steam) and the polyurea hard segments in the PUH elastomers at the high spinning temperatures, while the residual solvent contents remaining at the same time have a reduced solvation effect, but this is only a tentative interpretation of the unexpected results.
• the steam spinning process according to the invention is very particularly advantageous for coarser titers (about ⁇ 500 dtex, preferably ⁇ 1000 dtex) and for relatively coarser filament individual titers (from about 10 to 25 dtex of the weak in the final state of the elastomer filament yarns glued ("coalesced") single filaments (see literature).
• coarse titers about ⁇ 500 dtex, preferably ⁇ 1000 dtex
• relatively coarser filament individual titers from about 10 to 25 dtex of the weak in the final state of the elastomer filament yarns glued ("coalesced") single filaments
• the take-off speed can be increased to at least twice (!)
• the take-off speed for example from about 250 to 280 m / min to 500 to 600 m / min and thus with at least twice the shaft capacity
• the same type of spinning equipment shaft length equal, shaft diameter equal, spinning hot air media quantity approximately the same, spinning solution temperature identical
• the same PUH elastomer solutions are spun without the thread characteristics being undesirably changed if a sufficient amount is overheated Steam is used as hot spinning medium instead of hot air.
• the residual content of spinning solvent dimethylacetamide compared to hot air is from about 1.5 to 3% by weight or higher, to ⁇ 1.5% by weight, mostly even ⁇ 1.0% by weight, although the spinning performance was increased considerably and although high filament single titer or total titer was spun.
• the method according to the invention is particularly suitable for medium and coarse titers (approx. 250 to 560 dtex; or> 560 dtex, in particular> 800 dtex) and in particular for thicker single filaments, e.g. ⁇ 8 dtex, advantageous because threads with a low residual solvent content are obtained even under these difficult conditions.
• the process according to the invention is also of great advantage for the fine titer elastomer threads, whereby it turns out to be essential to spin such fine titer at relatively high temperatures - without risk of decomposition of the solvents dimethylformamide and especially dimethylacetamide - and thus to achieve economical production performance and a substantially increased spinning speed .
• This is particularly the case with spinning processes, where 4, 8, 16 or even 24 thread groups (for example each of 3 to 6 individual filaments) from a single dry spinning shaft.
• the new process also enables product-saving and ecologically better spinning conditions to be achieved.
• All diamine chain-extended, segmented PUH elastomers are suitable as polyurethane urea elastomer threads. They are made from NCO prepolymers with about 1.5 to 4% by weight of the NCO end groups and diamines as chain extenders. Aliphatic, cycloaliphatic or araliphatic diamines or their mixtures are used as diamines in the narrower sense, e.g.
• Monoamines can also be used in small amounts as chain terminators / chain regulators.
• the diamines in the broader sense also include hydrazine and dihydrazide compounds, e.g. Carbodihydrazide, hydrazide semicarbazide, semicarbazide carbazine ester and the like. Links.
• the NCO prepolymers are made from higher molecular weight diols, e.g. polyesters (including polylactones), polyethers, preferably polyoxytetramethylene diols, polyether esters etc., with a molecular weight of about 1000 to 4000, by reaction with excess amounts (e.g. 1.5 to 2.5 mol) of diisocyanates such as 4,4'-diphenylmethane diiso cyanate (MDI), tolylene diisocyanate or 1,3-cyclohexane diisocyanate, produced in the melt or preferably in solvents.
• diisocyanates such as 4,4'-diphenylmethane diiso cyanate (MDI), tolylene diisocyanate or 1,3-cyclohexane diisocyanate, produced in the melt or preferably in solvents.
• MDI 4,4'-diphenylmethane diiso cyanate
• NCO prepolymers with about 1.5 to 2.9% N
• NCO prepolymer e.g. N-methyldiethanolamine or N-methyl-bis- ( ⁇ -hydroxypropyl) amine.
• the NCO prepolymer (solution) s can be reacted continuously or batchwise with the diamine compounds in highly polar solvents such as dimethylformamide or dimethylacetamide, the NCO / NH2 equivalent ratios being approximately between 0.9 and 1.1.
• the polyurethane urea elastomer spinning solutions generally have viscosities of about 50 to 250, preferably 70 to 180 Pas at room temperature.
• the concentrations are generally between 20 to 35% by weight, preferably 22 to 30% by weight.
• the spinning solutions can contain customary additives and stabilizers, e.g. white pigments such as titanium dioxide (rutile or anatase), zinc oxides of any purity, zinc sulfide, color pigments or dyes, stabilizers and anti-aging agents, UV stabilizers, non-stick agents such as magnesium stearate and / or zinc stearate (e.g. 0.1 to 0.8% by weight - or any mixtures thereof), zinc oxides, optionally containing up to 4% other oxides such as magnesium oxide, or magnesium carbonate, flow improvers such as silicone oils (polydimethylsiloxanes) or soluble polyoxyalkylene / dimethylsiloxane copolymers. Suitable substances are often named here in the literature.
• the elastomer solutions are filtered and fed to the individual spinning chutes. Before being introduced into the spinnerets, the solutions have to be preheated to such an extent that they heat up to at least 100 ° C within the spinnerets, although temperatures of 90 to 95 ° C are sufficient when the solution is supplied and the remaining heat supply exceeds that in the high temperature range ( Spinn Kunststoff / steam / shaft heating) is effective to keep the solution temperature and nozzle surface temperature to over 100 ° C to just below the boiling point of the solvent dimethylformamide / dimethylacetamide, preferably 105 to 135 ° C, it is more reliable to process the solution temperature during the supply Einlie 100 ° C. This can e.g. happen via short preheating sections and circulation via static mixer elements.
• the nozzles to be used are also installed in a preheated state ⁇ 100 ° C to prevent condensation of water vapor during spinning.
• spinning shafts with a length of 5 to 15 m, preferably 7 to 12 m, and diameters of 25 to 70, preferably 27 to 55 cm, are used as spinning shafts.
• the spinning chutes can be heated over their entire length or on partial lengths, if necessary with different temperatures.
• the steam is supplied by a steam heater, which is located at a certain distance from the spinning chimneys. There, in general, somewhat higher temperatures are generated in the steam in order - depending on the insulation / removal etc. - to have the temperatures mentioned on the spinning shaft. The quantities are e.g. certain about pinholes. The temperatures of the steam are determined approximately at the level of the spinnerets.
• the amount of 50 m3 / h superheated steam has a flow rate of 812 m / h (0.225 m / sec).
• the ratio H represents the quotient from the enlarged shaft cross-section to the shaft cross-section of 615 cm2 (28 cm shaft diameter).
• the amount of steam is preferred only to a part of this ratio H, e.g. 0.1 H to 0.8 H (i.e. only a 10% to 80% increase above the amount of steam for the "normal" spinning shaft diameter of 28 cm).
• the increase in the amount of steam is only 0.2 H to 0.6 H.
• the smaller value of x.H is selected especially for the larger shaft diameters.
• the amount of steam is generally reduced to the lowest value necessary for the process set. If the elastomer solution throughput (shaft capacity) and the shaft cross-section are increased at the same time, more steam will tend to be used than if only the shaft cross-section was increased.
• a polyester with terminal hydroxyl groups and an average molecular weight of 2,000 (OH number of 56) was obtained by reacting 10 kg of adipic acid with 8.1 kg of 1,6-hexanediol and 7.1 kg of 2,2-dimethyl-propanediol-1. 3 (neopentyl glycol) prepared in the usual way.
• a homogeneous, clear elastomer solution with a solids content of 22% by weight and a solution viscosity of 92.6 Pas was obtained.
• 4% by weight of titanium dioxide, 0.3% by weight of magnesium stearate and 1% of the silicone oil Baysilon® M100 (Bayer AG) were added to the viscous polymer solution.
• the solution was further treated with 1% Cyanox® 1790 (stabilizer of the formula 2,4,6-tris (2,4,6-trimethyl-3-hydroxybenzyl) isocyanurate).
• a 22% by weight polyurethane urea elastomer solution in dimethylacetamide was spun on a 8.8 m long spinning shaft with an inner diameter of 28 cm from a 96 hole nozzle with a 0.3 mm hole diameter to give elastomer threads with 1200 dtex fineness.
• the threads were drawn off under the spinning shaft on a first godet at 375 m / min, taken over from a second godet at 390 m / min and wound onto bobbins at a winding speed of 450 m / min.
• the spinning shaft (wall heating) temperature was 200 ° C. It was spun with 56 Nm3 / h hot air at 380 ° C. Solution lines and spinning head were preheated to 110 ° C.
• the 22% by weight PUH elastomer solution in dimethylacetamide described above was spun into threads on an 8.8 m long spinning shaft with a cross section of 28 cm from a 96 hole nozzle with a hole diameter of 0.3 mm. 300 cm3 of spinning solution (approx. 100 ° C.) per minute were pressed through the nozzle.
• the speed of godet 1) was 415 m / min, of godet 2) 435 m / min and the winding speed was 500 m / min.
• the spinning shaft temperature (shaft heating) was 200 ° C. It was spun with 40 kg / h superheated steam from 400 ° C (measured on the steam heater / 310 to 320 ° steam temperature near the nozzle). Solution lines and spinning head were preheated to 110 ° C.
• the PUH elastomer solution mentioned was spun in dimethylacetamide with 353 cm 3 of spinning solution at 110 ° C. per minute.
• the speed of godet 1) was 410 m / min, of godet 2) 545 m / min and the winding speed was increased to 600 m / min. It was spun with 45 kg / h steam at 400 ° C (on a steam heater / correspondingly 320 ° near the nozzle).
• the shaft temperature was 225 ° C.
• the speed was increased from godet 1) to 585 m / min, from godet 2) to 610 m / min and the winding speed to 700 m / min and the amount of elastomer solution passed through was increased to 414 cm 3 / min.
• the other spinning parameters were kept unchanged. Threads of 916 dtex fineness were obtained.
• the fiber technology properties largely corresponded to the values from Example 3 / first part of the experiment, the residual spinning solvent content in the threads was only 0.96% by weight, despite the increased spinning performance.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Artificial Filaments (AREA)
• Polyurethanes Or Polyureas (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

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Citations (6)

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• 1989
  • 1989-04-17 DE DE3912510A patent/DE3912510A1/de not_active Withdrawn
• 1990
  • 1990-04-04 US US07/504,491 patent/US5057260A/en not_active Expired - Fee Related
  • 1990-04-04 DE DE59009228T patent/DE59009228D1/de not_active Expired - Fee Related
  • 1990-04-04 EP EP90106457A patent/EP0393422B1/fr not_active Expired - Lifetime
  • 1990-04-04 ES ES90106457T patent/ES2072938T3/es not_active Expired - Lifetime
  • 1990-04-17 JP JP2099471A patent/JP2909137B2/ja not_active Expired - Lifetime
  • 1990-04-17 KR KR1019900005298A patent/KR0154332B1/ko not_active IP Right Cessation

Patent Citations (6)

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