EP0643159A1 - Process for the production of spandex fibres containing a combination of polydimethylsiloxane and ethoxylated polydimethylsiloxane - Google Patents

Abstract

The invention relates to a spinning process, in particular to a dry-spinning process, for producing elastane (spandex) fibres by adding to the elastane spinning solution, before spinning, 0.8 to 2% by weight of polydimethylsiloxane having a viscosity of 50 to 300 cSt and 0.2 to 0.6% by weight of ethoxylated polydimethylsiloxane having a viscosity of 20 to 150 cSt.

Description

The invention relates to a spinning process, in particular a dry spinning process, for producing elastane fibers, in which the elastane spinning solution contains 0.8 to 2% by weight of polydimethylsiloxane with a viscosity of 50 to 300 cSt and 0.2 to 0.6% by weight before spinning. -% ethoxylated polydimethylsiloxane with a viscosity of 20 to 150 cSt can be added.

Elastane fibers are fibers that consist of at least 85% by weight of segmented polyurethanes. The elastic and mechanical properties of such fibers are achieved by using, for example, polyurea polyurethanes made from aromatic diisocyanates to produce the elastane fibers. Such elastanes are usually produced by spinning solutions using the wet spinning or preferably the dry spinning method. Suitable solvents in both processes are polar solvents, e.g. Dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide and preferably dimethylacetamide.

Commercial yarns made from such fibers have been known for many years. The most important area of application for these fibers is the elasticizing function for laundry, corsetry and bathing material as well as the use in garters, Sock edges or elastic bands. By far the largest amount of elastane filament yarns are processed on warp knitting and Raschel machines for the large areas of bathing and bodice wear. For this purpose, up to 1500 threads are wound side by side on a warp beam on an "expander warping system" with constant, controlled stretching. A chain, consisting of several warp beams, is then processed together with one or more chains of non-elastic base yarns (eg polyamide) to a wide product. By dyeing and finishing these goods, fabrics containing elastane with elastane fiber content of max. approx. 20% manufactured, which not only receive color and appearance, but also their final textile technology and mechanical (elastic) properties through these downstream processes.

It is only at this stage of the production that it turns out that the textile goods, when they are dyed in a uniform color, often have visible, strip-like irregularities which render the textiles unusable or only usable to a limited extent. The causes of this streaking are assumed to be irregularities in the thickness or stretching force of the elastane threads used, the exact assignment of the cause being very difficult since the undesired streaking can only be recognized after a large number of process steps have been carried out.

The object of this invention is to provide improved elastane fibers which, after processing on warp knitting machines in dyed and finished textile fabrics, produce a significantly lower streakiness without impairing the processability in the intermediate steps required for the manufacture of the goods.

Surprisingly, it was found that this goal can be achieved by prior to spinning the polyurethane-urea solution into this solution, a mixture of polydimethylsiloxane (PDMS) with a viscosity of 50 to 300 cSt and ethoxylated polydidimethylsiloxane and then carries out the spinning process.

• A) von 0,8 bis 2 Gew.-% Polydimethylsiloxan einer Viskosität von 50 bis 300 cSt und
• B) von 0,2 bis 0,6 Gew.-% ethoxyliertes Polydimethylsiloxan mit einer Viskosität von 20 bis 150 cSt,

jeweils gemessen bei 25°C mit einem Kugelfallviskosimeter, zugesetzt werden, wobei sich die angegebenen Gewichtsprozente auf den Gehalt der Siloxane in der fertigen Faser beziehen. Eine Viskosität von 50 cSt beim eingesetzten PDMS darf hierbei auf keinen Fall unterschritten werden, da sonst der erwünschte Effekt nicht mehr auftritt. Die einsetzbaren ethylenoxidmodifizierten Polydimethylsiloxane haben bevorzugt folgende allgemeine Formel: I

wobei PE der einbindige Rest CH₂CH₂-CH₂O(Eo)_mZ ist.The invention relates to a process for the production of elastane fibers from polyurea polyurethanes by dry spinning or wet spinning with the steps of spinning, removing the spinning solvent, preparing, optionally twisting and winding the spun fibers, characterized in that the spinning solution before spinning

• A) from 0.8 to 2 wt .-% polydimethylsiloxane with a viscosity of 50 to 300 cSt and
• B) from 0.2 to 0.6% by weight of ethoxylated polydimethylsiloxane with a viscosity of 20 to 150 cSt,

each measured at 25 ° C. with a falling ball viscometer, the percentages by weight based on the content of the siloxanes in the finished fiber. The viscosity of the PDMS used must not fall below 50 cSt, otherwise the desired effect will no longer occur. The usable ethylene oxide-modified polydimethylsiloxanes preferably have the following general formula: I

where PE is the monovalent radical CH₂CH₂-CH₂O (Eo) _m Z.

In this formula, Eo = ethylene oxide and Z is either hydrogen or a C₁-C₆ alkyl radical. x, y and m are integers greater than or equal to 1, which are preferably chosen so that formula (I) does not exceed the molecular weight of 4,000.

Products of this type are manufactured, for example, by Union Carbide under the trade name Silwet®. Particularly suitable for the use according to the invention are those types which have a viscosity of 20 and 150 cSt and a molecular weight of approximately 600 to 4000. Unless expressly stated otherwise, all molecular weight data relate to the number average (M _n ).

The spinning of pure polydimethylsiloxane (PDMS) is generally known. It is described, for example, in DE-A-3 912 510, which describes the production of elastanes by a special spinning process, namely a dry spinning process for the production of coarse titer elastane fibers with the introduction of superheated steam. Silicone oils are mentioned among other possible additives as flow improvers. U.S. Patent 4,973,647 also mentions silicone oil spinning. Nothing in the document says anything about the effects of the oil after further processing. There is no mention of a special combination of oils with certain properties.

The spinning of amylsiloxane-modified polydimethylsiloxane oils, which is not the subject of the invention, is known from the document DE-AS 1 469 452.

None of these publications gives an indication of whether the spinning of pure or modified PDMS could influence or improve the fiber properties, in particular the optical uniformity of elastic warp-knitted fabrics made from these elastane fibers.

It is also known to apply mixtures of polydimethylsiloxane and polyether-modified PDMS to the finished spun elastane thread by dipping, spraying or using a roller (see JP 57 128 276 or JP 03 146 774).

The application of such preparation oils serves to improve the drainage properties of the elastane fibers in warping and knitting processes. The spinning of the mixtures is not mentioned in these documents. There is also no indication that mixtures, in particular those with the compositions according to the invention, spun into the elastane fibers bring about an improvement in the optical properties of the warp-knitted fabric obtained.

The polyurea polyurethanes are produced by methods known per se. The synthetic structure of the fiber raw materials according to the prepolymer process has proven particularly useful, with a long-chain diol in the solvent or in the melt being reacted with a diisocyanate to form a prepolymer in the first process step in such a way that the reaction product contains isocyanate end groups.

Polyester diols and polyether diols are preferred as diols. Mixtures of polyester and polyether diols are also suitable. The diols generally have a molecular weight of 1000 to 6000.

Suitable polyester diols are, for example, dicarboxylic acid polyesters which can contain both several different alcohols and several different carboxylic acids. Mixed polyesters of adipic acid, hexanediol and neopentyl glycol in a molar ratio of 1: 0.7: 0.43 are particularly suitable. Suitable polyesters preferably have a molecular weight of 1000 to 4000.

Suitable polyether diols are e.g. Polytetramethylene oxide diols, preferably with molecular weights from 1000 to 2000.

Polyester or / and polyether diols can also be used in combination with diols which contain tertiary amino groups. For example, N-alkyl-N, N-bis-hydroxyalkylamines are particularly suitable. The following are examples of components:
4-tert-butyl-4-azaheptanediol-2,6,4-methyl-4-azaheptanediol-2,6,3-ethyl-3-azapentanediol-1,5,2-ethyl-2-dimethylaminomethyl-1,3 propanediol, 4-tert-pentyl-4-azaheptanediol-2,6, 3-cyclohexyl-3-azapentanediol-1,5, 3-methyl-3-azapentanediol-1,5, 3-tert-butylmethyl-3-azapentanediol -1.5 and 3-tert-pentyl-3.azapentanediol-1.5.

In the synthesis of the elastane raw materials, the customary aromatic diisocyanates are optionally used in a mixture with small proportions of aliphatic diisocyanates. Particularly useful results are obtained with the following diisocyanates:
2,4-tolylene diisocyanate and corresponding isomer mixtures, also 4,4'-diphenylmethane diisocyanate or corresponding isomer mixtures. It is of course possible to use mixtures of aromatic diisocyanates.

Another embodiment of the synthesis of elastane raw materials according to the invention consists in mixing polyester and polyether polyurethane prepolymers and then converting them into polyurea polyurethanes in a known manner. The mixing ratio of polyester and polyether diols, which is favorable for the respective technical purpose, can easily be determined by preliminary tests.

In polyurea-polyurethane synthesis, the desired urea groups are introduced into the macromolecules through a chain extension reaction. The macro-diisocyanates synthesized in the prepolymer stage are usually reacted in solution with diamines. Suitable diamines are e.g. Ethylene diamine, tetramethylene diamine, 1,3-cyclohexane diamine, isophorone diamine and mixtures of these diamines. By using a small amount of monoamines, e.g. Diethylamine or dibutylamine, the desired molecular weight can be adjusted during chain extension. The chain extension itself can be carried out using CO₂ as a retardant.

A mixture of polyester and polyether polyurethane ureas can also be carried out after the elastane synthesis has been completed.

The reactions described are usually carried out in an inert polar solvent such as dimethylacetamide, dimethylformamide or the like.

The silicone oils are introduced by the process according to the invention in concentrations of 0.8 to 2% by weight, based on the polydimethylsiloxane or 0.2 to 0.6% by weight, based on the ethoxylated polydimethylsiloxane. The weight ratio of PDMS to ethoxylated PDMS in the finished phase is preferably from 1: 1 to 5: 1. The concentration data mean the oil content in the finished spun elastane filament. The oils are introduced using a master batch in which the oils are dispersed in the solvent together with other spinning aids, such as, for example, a non-stick agent, for example dimethylacetamide. This master batch is then mixed into the spinning solution using a static or other mixer. The concentration of both silicone oils together in the base batch is preferably from 15 to 22% by weight.

The elastane filaments are then produced from the spinning solution obtained by the wet spinning or dry spinning process, preferably the dry spinning process. Fibers produced by the method according to the invention preferably have a single titer of 10 to 160 dtex. Multifilament fibers consisting of 3 to 5 coalesced individual capillaries are particularly preferred. They preferably have a titer of approximately 33 to 55 dtex.

After leaving the spinning shaft, the fibers can be provided with a conventional external preparation, which ensures processing in the subsequent warping and knitting processes.

The elastane fibers obtainable by the process according to the invention are a further subject of the invention.

The test method described below was used to show that the elastane threads produced according to the invention bring about a significantly better uniformity of the knitted flat fabric than those which were produced by a standard method.

Description of the test procedure

In the first step, 1340 threads of diter 45 are tied on an elastane warping machine (type DSE 50/30 from Karl Mayer, Oberhausen) with a pre-stretching of 156% and a final stretching of 40% on two part warp beams (TKBs).

In the second step, an elastic warp knit fabric is made from these partial warp beams together with two TKBs made of polyamide dtex 44/10 from SNIA. A warp knitting machine of the type HKS 2 / E 32 (from Karl Mayer, Oberhausen) used. The thread run-in values are 59.0 cm for the elastane and 160.0 cm for the polyamide.

The warp-knitted fabric produced in this way is then relaxed on a steaming table with a vibration device, the differences in stitch density and fabric width contained in the raw fabric being largely compensated for.

In the further process, hot air fixation is carried out on a tensioning frame in the non-prewashed state for 40 seconds at 195 ° C. and an advance of 8%. The fixing width is 100 cm.

In a separate tenter frame, the fixed goods are cold wound on perforated dyeing trees.

• A) Für die Farbe Weiß:
  2,0 g/l Blankit IN (Fa. BASF AG; techn. Natriumdithionit)
  2,0 % Blankophor CLE fl. (Fa Bayer AG; optischer Aufheller für Polyamid, Elastan)
  0,3 ml/l Essigsäure
  Vor Zugabe aller Hilfsmittel wird der verschlossene Apparat zunächst ohne Flottenzirkulation mit Wasser gefüllt (gute Entlüftung). Die Zugabe der zuvor erwähnten Hilfsmittel erfolgt, nachdem die Zirkulationspumpe eingeschaltet und der vorgesehene Druck von 2,2/2,0 bar eingestellt ist. Das Aufheizen der Flotte erfolgt bei 1°C pro Minute, wobei bis 80°C die Flottenrichtung Außen/Innen gewählt wird und ab 80°C die Flotte von Innen nach Außen gepumpt wird. Nach Erreichen der vorgesehenen Endtemperatur von 90°C beträgt die weitere Behandlungszeit noch 45 Minuten. Anschließend wird indirekt abgekühlt bis auf 70°C, danach durch Zulauf von frischem, kaltem Wasser kontinuierlich gespült bis auf Raumtemperatur und abschließend noch einmal mit frischem Wasser gespült.
• B) Für die Farbe Blau:
  Die Vorgehensweise im Baumfärbeapparat entspricht weitgehend der für die Farbe Weiß, ausgenommen folgende Änderungen der Färbemittelzusammensetzung:
  0,90 % Telon Lichtblau RR 182 % (Fa. Bayer AG; Säurefarbstoff)
  0,05 % Telon Echtorange AGT 200 % (Fa. Bayer AG; Säurefarbstoff)
  2,00 g/l Natriumacetat
  1,50 % Levegal FTS (Fa. Bayer AG; Egalisiermittel, Mischung aus Sulfonat und Polyglykolether-Derivat)
  0,30 ml/l Essigsäure
  Färbezeit 60 min bei 98°C.
  Nach der Färbung werden die Färbebäume mit der nassen Ware dem Foulard vorgelegt, bei der Foulardpassage durch Spülwasser gefahren und gleichmäßig abgequetscht.
  Die anschließende Zwischentrocknung erfolgt im Siebtrommeltrockner bei 120°C mit einer Laufgeschwindigkeit von ca. 7 m/min. Im Auflauf des Siebtrommeltrockners wird die Ware abgetafelt.
  Die zwischengetrocknete Ware wird abschließend im Spannrahmen bei einer Temperatur von 150°C mit einer Warengeschwindigkeit von 10 m/min und einer Voreilung von 5 % fertig gespannt, wobei eine glatte Fertigware in vorgeschriebener Warenbreite resultiert, die im Spannrahmenauslauf aufgewickelt wird.

The coloring is done in the tree dyeing machine, either in white or in blue, following the following standard recipes:

• A) For the color white:
  2.0 g / l blankite IN (from BASF AG; technical sodium dithionite)
  2.0% Blankophor CLE fl. (Bayer AG; optical brightener for polyamide, elastane)
  0.3 ml / l acetic acid
  Before adding all auxiliary materials, the closed apparatus is first filled with water without circulation of the liquor (good ventilation). The aids mentioned above are added after the circulation pump is switched on and the intended pressure of 2.2 / 2.0 bar is set. The liquor is heated at 1 ° C. per minute, the liquor direction being up to 80 ° C. Outside / inside is selected and the liquor is pumped from inside to outside from 80 ° C. After reaching the intended final temperature of 90 ° C, the further treatment time is 45 minutes. The mixture is then cooled indirectly to 70 ° C., then rinsed continuously by adding fresh, cold water to room temperature and finally rinsed again with fresh water.
• B) For the color blue:
  The procedure in the tree dyeing machine largely corresponds to that for the color white, except for the following changes in the colorant composition:
  0.90% Telon light blue RR 182% (Bayer AG; acid dye)
  0.05% Telon Echtorange AGT 200% (Bayer AG; acid dye)
  2.00 g / l sodium acetate
  1.50% Levegal FTS (Bayer AG; leveling agent, mixture of sulfonate and polyglycol ether derivative)
  0.30 ml / l acetic acid
  Dyeing time 60 min at 98 ° C.
  After dyeing, the dyeing trees with the wet goods are presented to the foulard, passed through rinse water in the foulard passage and squeezed out evenly.
  The subsequent intermediate drying takes place in a sieve drum dryer at 120 ° C with a running speed of approx. 7 m / min. The goods are unloaded in the casserole of the screen drum dryer.
  The intermediate-dried goods are finally stretched in the stenter at a temperature of 150 ° C at a speed of 10 m / min and a lead of 5%, resulting in a smooth finished product in the specified width, which is wound up in the stenter outlet.

The assessment of the optical uniformity is carried out by an optical inspection of the finished dyed goods both in transmitted light and in reflected light and is assessed using a grading scale (test grade), which ranges from 1 to 9. This grading scale is valid for all elastane finenesses. Grades from 1 to 3 can only be achieved with coarser titles (> dtex 80). For the dtex 45 described here, grade 4 represents a very even product, grade 5 only corresponds to good uniformity, grade 6 corresponds to a satisfactory uniformity, which is still excellent.

If a product is rated with grade 7, it can only be used as a special item, goods with grades from 8 to 9 are not for sale.

Examples

The following examples demonstrate the more favorable optical uniformity of colored knitwear made with elastanes according to the invention.

The superiority of the elastane fibers of the invention (see Examples 1, 3, 5 and 7 according to the invention) becomes clear in comparison to fibers which differ in composition only in terms of the spinning of the mixtures of polydimethylsiloxane and ethoxylated polydimethylsiloxane (examples: 2, 4 , 6, 8 and 9).

In all examples, the knitwear was made from an elastane polymer made from a 2000 molecular weight polyester diol consisting of adipic acid, hexanediol and neopentyl glycol, capped with methylene bis (4-phenyl diisocyanate) ("MDI") and then capped with chain extension of a mixture of ethylenediamine (EDA) and diethylamine (DEA).

The elastane polymer for each of the examples was made using essentially the same procedure.

In all cases, 49.88 parts by weight of 2000 molecular weight polyester diol were mixed with 1.00 part by weight of 4-methyl-4-azaheptanediol-2.6 and 36.06 parts by weight of dimethylacetamide (DMAC) and 13.06 parts by weight of MDI at 25 ° C Heated at 50 ° C. and held at this temperature for 110 minutes in order to obtain an isocyanate-capped polymer with an NCO content of 2.65% NCO.

In Examples 1 and 2, after cooling, 100 parts of the capped polymer were cooled down to 25 ° C. and quickly mixed in to a solution of 1.32 parts by weight of EDA, 0.03 parts by weight of DEA in 189.05 parts of DMAC that a spinning solution of the polyurethane-urea in DMAC with a solids content of 22.5% was formed.

By adding hexamethylene diisocyanate (HDI), the molecular weight of the polymer was adjusted so that a viscosity of 70 Pa.s / 25 ° C and an inherent viscosity η _inh. of 1.4 dl / g resulted.

For the remaining examples, the chain extension was carried out as follows: 100 parts of the capped polymer were cooled down to 20 ° C. and then this solution was diluted with 59.85 parts by weight of DMAC. This solution was then mixed intensively in a continuous reactor with a mixture of 1.23 parts by weight of EDA, 0.08 parts by weight of DEA and 60.72 parts by weight of DMAC, so that a spinning solution of polyurethane-urea in DMAC with a solids content of approx. 30% and a viscosity of 50 Pa.s / 50 ° C with an inherent viscosity η _inh. of 1.4 dl / g.

After the preparation of the polymers described in the previous section, a stock of additives was added to them. This stock batch consisted of 58.72 parts by weight of DMAC, 10.32 parts by weight of Cyanox® 1790 (American Cyanamid; stabilizer), 5.16 parts by weight of Tinuvin® 622 (Ciba Geigy; stabilizer), 25.80 parts by weight of 30% spinning solution and 0.009 part by weight of the dye Makrolexviolett® B (Bayer AG). This stock batch was metered into the spinning solution in such a way that the content of Cyanox® 1790 in the finished thread was 1% by weight and the content in Tinuvin® 622 was 0.5% by weight, based on the solids of the fiber polymer.

A second stock batch was mixed into this spinning solution, consisting of 30.94 parts by weight of titanium dioxide type RKB 2 (Bayer AG), 44.52 parts by weight of dimethylacetamide and 24.53 parts by weight of 22% spinning solution, in such a way that a titanium dioxide content of 0.05% by weight, based on the polyurethane-urea polymer, resulted in the finished thread.

Further stock batches were now mixed into this spinning solution. They consisted of 4.4 parts by weight of magnesium stearate, 32.3 parts by weight of DMAC, 41.2 parts by weight of 30% spinning solution and proportions of polydimethylsiloxane and ethoxylated polydimethylsiloxane, which were chosen so that the percentages given in Examples 1 to 9 in the finished fiber resulted.

Example 1: Additive content in the finished fiber

0.3% by weight magnesium stearate
0.3% by weight of Silwet® L 7607 (Union Carbicle; ethoxylated PDMS)
1.0% by weight of Baysilonöl® M 100 (Bayer AG) with a viscosity of 100 cST

Example 2 (comparison): Additive content in the finished fiber

0.3% by weight magnesium stearate without polydimethylsiloxane
0.3% by weight of Silwet® L 7607
In Examples 1 and 2, the spinning solution was spun dry by means of spinnerets in a typical spinning apparatus of 5 m in length to filaments with a titer of 11 dtex, 4 individual filaments in each case being combined to form coalesced filament yarns of 44 dtex and wound up at 330 m / min .

As can be seen from Table 1, by spinning a mixture of polydimethylsiloxane and ethoxylated polydimethylsiloxane according to the invention, a clear improvement in the optical uniformity, expressed by a grade improvement of 0.76 points, is achieved. Table 1 Improvement of optical uniformity according to the invention example Number of exams Test grade (average) Remarks 1 12th 5.04 According to the invention, viscosity of the PDMS: 100 cSt 2nd 10th 5.80 Comparison, without spun PDMS

Example 3: Additive content in the finished fiber

0.3% by weight magnesium stearate
0.3% by weight Silwet® L 7607 (Union Carbide)
1.0% by weight of Baysilonöl® M 100 (Bayer AG) with a viscosity of 100 cST

Example 4 (comparison): Additive content in the finished fiber

0.3% by weight magnesium stearate
0.3% by weight Silwet® L 7607 (Union Carbide)
In the case of Examples 3 and 4, the spinning solution was spun dry in a spinning apparatus of 10 m in length to filaments with an individual titer of 11 dtex, 4 individual filaments being combined to form coalesced filament yarns of 44 dtex and wound up at 500 m / min.

As can be seen from Table 2, this modified spinning process also achieved a significant improvement in optical uniformity by 0.56 points by the procedure according to the invention. Table 2 Improvement of the optical uniformity according to the invention with a modified spinning process: example Number of exams Test grade (average) Remarks 3rd 64 5.50 According to the invention, viscosity of the PDMS: 100 cSt 4th 25th 6.06 Comparison, without spun PDMS

Example 5: Additive content in the finished fiber

0.3% by weight magnesium stearate
0.3% by weight of Silwet® L 7607
1.0% by weight of Baysilonöl® M 100 with a viscosity of 300 cST

Example 6: (comparison)

0.3% by weight magnesium stearate
0.3% by weight of Silwet® L 7607
0.75% by weight of Baysilonöl® M 100 with a viscosity of 100 cST

Example 7:

0.3% by weight magnesium stearate
0.3% by weight of Silwet® L 7607
1.5% by weight of Baysilonöl® M 100 with a viscosity of 100 cST

Example 8: (comparison)

0.3% by weight magnesium stearate
0.3% by weight of Silwet® L 7607
1.0% by weight of PDMS containing amylsiloxane

Example 9: (comparison)

0.3% by weight magnesium stearate without ethoxylated polydimethylsiloxane
1.0% by weight of Baysilonöl® M 100 with a viscosity of 100 cST
In the test series for Examples 5 to 9, the spinning solution was also dry spun by means of spinnerets in a spinning apparatus of 10 m in length to filaments with a titer of 11 dtex, 4 individual filaments each being combined into coalesced filament yarns of 44 dtex, which were combined with 500 m / min were wound up.

The results are summarized in Table 3. Table 3 Improvement of the optical uniformity according to the invention compared to spinning not according to the invention: example Number of exams Test grade (average) Remarks 5 1 4.83 According to the invention, viscosity of the PDMS: 300 cSt 6 3rd 5.25 According to the invention, viscosity of the PDMS: 100 cSt but concentration reduced to 0.75% 7 1 4.50 According to the invention, viscosity of the PDMS: 100 cSt but concentration increased to 1.5% 8th 3rd 5.58 Comparison, PDMS replaced by PDMS containing amylsiloxane 9 * * Comparison with spun PDMS, viscosity 100 cSt but without ethoxylated PDMS * No textile fabric was produced from this part of the test, since the warping led to permanent threading which continuously led to thread breaks.

In this series, too, the significant improvement in optical uniformity by 0.42 to 1.08 note points can be seen when the spinning additives according to the invention are used.

Claims (9)

Process for the production of elastane fibers from polyurea-polyurethanes by dry spinning or wet spinning with the steps spinning, removing the spinning solvent, preparation, optionally twisting and winding the spun fibers, characterized in that the spinning solution before spinning A) from 0.8 to 2% by weight of polydimethylsiloxane with a viscosity of 50 to 300 cSt and B) from 0.2 to 0.6% by weight of ethoxylated polydimethylsiloxane with a viscosity of 20 to 150 cSt, each measured at 25 ° C with a falling ball viscometer, the percentages by weight based on the content in the finished fiber. A method according to claim 1, characterized in that the elastane fibers are produced by dry spinning. Process according to claims 1 and 2, characterized in that the weight ratio of polydimethylsiloxane to ethoxylated polydimethylsiloxane in the finished fiber is 1: 1 to 5: 1. Process according to claims 1 to 3, characterized in that the number average molecular weight of the ethoxylated polydimethylsiloxane is from 600 to 4,000. Process according to Claims 1 to 4, characterized in that the ethoxylated polydimethylsiloxane has one of the general formula (I)

is, in the PE the monovalent radical -CH₂CH₂-CH₂O (Eo) _m Z, in which Z is hydrogen or a C₁-C Alkyl-alkyl radical and Eo is an ethylene oxide unit and X, Y and m are independently of one another greater or equal for a whole number 1 and are chosen so that the molecular weight of 4,000 is not exceeded. Process according to claims 1 to 5, characterized in that the polydimethylsiloxanes A) and B) in the form of a 15 to 22% by weight stock solution in the spinning solvent, based on the proportion of A) + B), are added to the spinning solution. Process according to claims 1 to 6, characterized in that the individual titer of the spun threads is from 10 to 160 dtex. Process according to claims 1 to 7, characterized in that the spun fibers are multifilament fibers with 3 to 5 capillaries and have a total titer of 30 to 60 dtex. Elastane fibers obtainable from a process according to claims 1 to 8.