DE3508955C2 - Process for high-speed spinning and drawing of synthetic yarns - Google Patents

Abstract

Method for producing highly oriented and crystallized smooth yarns made of polyester, polyamides or polypropylene in a one-step process by direct drawing, heat-setting and relaxation after spinning and before winding the yarns at a speed of at least 4500 m/min, wherein the godets and thread deflection elements of the spinning take-off (S1) and drawing system (S2) are arranged axially parallel to one another and are not offset from one another in depth and are wrapped around by the yarns in a meandering manner, and the thread offset from system S1 to system S2 is a maximum of 0.15°, and wherein the speed ratios of the systems S1 and S2 are selected to be high enough that orientation drawing takes place, and wherein at least one heating device is included in or between the system S1 and the winding unit, the dimensions of which have been selected such that the thread dwell time is at least 4 msec and which has a temperature of at least 130°C, and wherein the produced Yarns have a requirement profile which makes them universally usable in smooth yarn processing.

Description

The invention relates to a process for producing highly oriented and crystallized smooth yarns made of polyester, polyamides or polypropylene according to the preamble of claim 1, cf. DE-OS 31 46 054.

The use of a single-stage process with a high winding speed in the range of greater than or equal to 4500 m/min means rapid spinning of the threads corresponding to a high spinning take-off speed of the spinning take-off system S 1.

The roving before entering this spinning take-off system S 1 is not directly accessible in the single-stage process, but must be considered as pre-oriented yarn (POY) due to the speed condition.

The direct drawing of this roving is achieved by applying a speed ratio between the two godet systems of the spinning take-off system S 1 and the drawing system S 2, in each of which there is an adhesion point of the yarns to fix the drawing. The speed ratio is selected to be high enough to achieve a thread tension in the field between S 1 and S 2 that corresponds to the drawing tension and is significantly higher than the thread tension of the roving before entering the system S 1.

Direct heat-setting is achieved by using heating devices, whereby the yarn, which is highly oriented and crystallized after drawing, is exposed to temperatures which essentially lead to a structural stabilization of the yarn after winding and cause a reinforcement of the wound yarn within the limit of less than or equal to 1%.

Relaxation means the application of a speed ratio of the speeds of the winding unit in relation to the system S 2 of less than or equal to 1.0, whereby the stretching tension is reduced to a low level directly in front of the winding unit, so that when detangling devices are used at this point, sufficiently high knot numbers are achieved in the yarn or that an optimal bobbin structure is achieved during winding.

The use of godet and thread deflection elements arranged axially parallel to one another and not offset in depth as spinning take-off (S 1) and drawing system (S 2) excludes multiple wrapping of these systems by the yarns.

The highly oriented and crystallized smooth yarn produced by the one-stage process must essentially meet the same requirements as smooth yarn produced by conventional two-stage processes.

Such a conventional process involves spinning the threads and then winding them, a

Conditioning phase of this spinning yarn and the presentation of the spinning bobbins to a draw-twisting machine, in which the finished flat yarn is produced by drawing and possibly thermosetting and wound onto bobbins. This bobbin yarn is used in further processing such as knitting, knitting and weaving, whereby these and the use of the finished product require certain textile-mechanical and thermal properties and stability of the yarn.

Single-step processes for high-speed spinning and drawing of synthetic yarns are already known from the literature.

For example, high-speed spinning processes are described which cause stretching during spinning and by applying thread tensions that correspond to the stretching tension. These processes are implemented using only two partially wrapped godets (see, for example, DE-OS 24 47 766). However, it has been shown that these yarns are insufficiently stabilized in their thermal behavior. Significant disturbances are found in further processing under tension and temperature. Furthermore, such yarns have insufficient mechanical stability against cyclical loading and unloading. Such stresses occur in the further processing processes. Such yarns perform particularly poorly when used as weft material in the weaving process. In addition to disturbances in fabric production, which lead to quality gradations, the woven fabric itself also shows disturbances caused by irreversible overstretching of the yarns.

This mechanical instability was also observed in nylon yarns produced using the conventional spin-draw process with multiple wraps. In this process, the draw ratio could not be set high enough to achieve a sufficiently high modulus in the yarn. Rather, the level of the draw ratio was limited by the occurrence of draw defects, in particular thread breaks and fluff in the yarn.

The spinning-stretching process according to US patent 42 37 187 uses two partially wrapped yarns, whereby the yarn is already stretched in the spinning-cooling area. The speed difference of the godets is limited to 0.5 - 2% overfeed. Orientation stretching is not carried out between the godets. According to the patent claim, the yarn produced in this way undergoes a residual stretching in a separate process of at least 1.3 in order to achieve a sufficiently low elongation at break of 45%. The spun yarn produced according to the patent is characterized by elongations at break of 45 - 70%, which are too high for direct further processing for some purposes, e.g. as a cop replacement material.

The German specification 22 04 535 describes a conventional high-speed spinning stretching process between godets with auxiliary rollers. To fix the stretching and fixing tensions, the threads are wrapped around the godet systems four times. Due to this multiple wrapping, the godet systems are necessarily offset from one another and not arranged parallel to the axis.

In the German patent application 31 46 054, the disadvantage of auxiliary rollers for thread laying is discussed in detail in connection with a spinning-stretching process. The solution to the process led to a partially wrapped godet in relation to the inlet godet system. In relation to the take-off godet system, multiple wrapping with 2 - 5 thread wraps is used. The godet systems are then necessarily offset from one another and not arranged parallel to one another. The use of a maximum of one partial wrap in the inlet godet system limits the thread tension ratios and thus the maximum stretch ratio that can be used in order to avoid the stretching point slipping in this system. Furthermore, this system requires that the surface quality of the godet be kept exactly constant and that it be coordinated with the ratios of stretching and spinning tension. For example, the use of a preparation in the blow shaft area, which is so important for thread uniformity, is excluded. In order to maintain high tension conditions, a chrome-plated godet surface must be used, but this is not suitable for reliable production due to its tendency to abrasion. For this reason, plasma-coated godets are usually used, which then inevitably have a lower coefficient of friction and limit the tension conditions that can be used.

The invention is therefore based on the object of specifying an economical method for producing highly oriented and crystallized smooth yarns made of polyester, polyamides or propylene in a one-step process, whereby the yarns should have a requirement profile which makes them universally usable in the smooth yarn processing processes, and whereby the production method enables a particularly gentle treatment of the yarn, which has a positive effect on the yield of full bobbins and the thread purity.

The solution of the stated problem is achieved in the method described at the outset by the characterizing measures of claim 1.

Preferably, the wrap angle around each godet is at least 90° and a maximum of 270°. The number M or N of godets or deflection elements for each of the systems S 1 and S 2 is preferably selected so that their total wrap angle and the total number of godets and deflection elements M + N is less than or equal to 10, where

F[deep]VS = ratio of the thread tensions in the drawing field F[deep]V (cN) to that in the spinning take-off field F[deep]S (cN) before entering the system S 1,

F[deep]VA = ratio of the yarn tensions in the drafting field F[deep]V (cN) to that after the system S 2 and before the winding unit F[deep]A (cN),

In = natural logarithm to base c.

Preferably the speed ratios are:

Between the godets of system S 1: R 1 = 1.0 to 1.06

(R 1 = 1, if S 1 only consists of

a galette)

Between the inlet godet of S 2

and the outlet godet of S 1: R 2 = 1.06 to 2.0

Between the godets of system S 2: R 3 = 1.06 to 0.92

(R 3 = 1, if S 2 only consists of

a galette)

The total stretch ratio, which results from the partial speed ratios, R = R 1 x R 2 x R 3 x R 4, is preferably between R = 1.06 to 1.84.

Preferably, the bobbin shrinkage of the wound yarn is at least 1.5% lower in absolute terms than that of a yarn without temperature application and the modulus of the yarn in the lower region of the stress-strain diagram is comparable to that of conventionally produced bobbin yarn.

A significant advantage of the invention is the cost-effectiveness of the process. Conventional spin-stretching machines for spin-stretching processes can only process a limited number of threads in one stretching unit. The necessary dwell times on heated godets and the fixing of the stretching tension require multiple wrapping around the godets. As a result, a thread offset of approx. 1 - 2° is absolutely necessary to maintain minimum distances between the various thread layers. The deflection of the thread after it has run off the godet as shown in Fig. 1 is referred to as the small alpha thread offset.

Conventional spinning and stretching machines therefore limit the number of threads per stretching unit to 4 - 8 threads, depending on the titre. When using economical spinning systems with 8 - 16 threads per position, 2 stretching units per position were therefore necessary. According to the method according to the invention, the number of threads per stretching unit is no longer limited. In the stretching unit according to the invention, at least twice as many threads or even threads from several spinning units can be processed in one stretching unit.

The conventional spinning-stretching principle of multiple wrapping is based on two requirements:

Firstly, it is the setting of the necessary yarn dwell time on heated godets,

on the other hand, there are the frictional retention forces necessary to build up the stretching tension and to reduce this tension to the level of the winding tension by applying appropriate wrap angles around the godets.

A relationship between stress ratios, the friction coefficient of a wrapped cylindrical pin and the wrap angle for the case of sliding friction is provided by the rope friction equation (Melliand Textilberichte 42/4 (1961) 374 - 379:

S 2/ S 1 = exp (µ x small gamma), where

S 1 = thread tension in front of the friction pin,

S 2 = Thread tension after the friction pin,

µ = friction coefficient of the friction pin,

small gamma = thread wrap angle around the friction pin.

Applying this formula to the wrap angle around godets during the spin-stretching process results in a wrap angle between 36 - 84° for a tension ratio of 1.4 for technically usual friction coefficients in the range µ = 0.23 - 0.54 and an angle of at least 117 - 274° for a tension ratio of greater than or equal to 3.0. These are the yarn angles for the occurrence of sliding friction on the godets. In practice, however, a combination of sliding and static friction occurs on the godets if, as in the process according to the invention, the stretching stresses in the godet systems are to be fixed. In particular, influences and fluctuations of the friction element and the yarn properties and parameters on the friction coefficient µ must be taken into account, so that this generally turns out to be not a constant, but a complex quantity of various influencing factors. In conventional spin-stretching processes, these uncertainties are taken into account by using multiple wraps.

It is surprising that in the method according to the invention the number of godets can be significantly lower than the conversion of the wrap angles of conventional systems. The method according to the invention therefore uses drawing units with godet numbers that correspond approximately to those of conventional units, with the advantage of processing at least twice the number of threads per unit.

A further advantage of the invention results from maintaining a thread offset of less than or equal to 0.15° from system S 1 to system S 2. Surprisingly, this significantly improves the running reliability of the yarn during the manufacturing process and the yarn purity. Due to the absence of the friction force component perpendicular to the thread running direction in comparison to the process with thread offset, the sensitivity of the thread adjustment is clearly significantly reduced and an abrasive effect leading to thread damage is significantly reduced.

There are at least 4% (rel.) fewer thread breaks, based on the same stretch ratio.

Furthermore, the purity of the yarn is considerably better. The number of capillary lint per thread length is almost halved. These effects significantly increase the efficiency of the further processing, which is the prerequisite for the use of such yarns in sensitive processes. The absolute number of faults is therefore determined less by the stretching unit, but essentially limited by the quality of the polymer raw material.

The spinning-stretching process according to the invention with high winding speeds can advantageously be operated with lower demands on the heating devices. While in multiple wrap systems the uniformity of the temperature across the entire godet width plays a central role in ensuring constant thread properties, which makes the previous godet heating systems complex, prone to failure and costly, the process according to the invention can use much simpler inductively heated godets, gas-heated chambers or contact plates. Much shorter dwell times are also necessary than with heated godet systems with multiple wrap.

Basically, the boiling shrinkage of the yarns produced according to the invention is lower than that of a conventional bobbin yarn. By increasing the temperature of the heating device, a further reduction of the boiling shrinkage by a few percent is possible (Fig. 5). At the same time, the shortening of the wound thread is limited to a maximum of 1%, which ensures an excellent bobbin structure. The yarns produced according to the invention prove to be more stable with regard to thermal post-treatment processes than conventional ones.

The stability of the yarns can be characterized by measurement, for example, a high modulus at 10% elongation, a low elongation after loading and a low hot air shrinkage under loading. The method according to the invention takes these requirements for the yarn into account and delivers excellent processing behavior. Errors caused by stretching are greatly reduced and the end quality of the yarns is so excellent that they can be used universally for all smooth yarn processing processes.

In the following, the method according to the invention is discussed with reference to the drawings:

Fig. 1 describes the thread offset small alpha when the thread wraps around two godets.

Fig. 2 shows a spinning-stretching system in simplified form, the design of which corresponds to Example 2.

The melted polymer is pressed at a defined flow rate through spinneret plates (1) that contain the desired number of capillary holes. Up to 16 such nozzle plates are combined in one spinning position. Several spinning positions can be arranged directly next to each other.

The threads emerging from the nozzle plates are cooled in a blowing shaft (2). After the threads have solidified, they are guided over a preparation device (3) and thread guides before they are led into the actual drawing unit. The drawing unit consists of the spinning take-off (S 1) and drawing system (S 2) as well as one or more winding units (4) for winding the threads. A heating device H is optionally provided between the systems S 1 and S 2 or between the system S 2 and the winding unit (example no. 7, 10, 11 and 16).

In the case of example no. 2, system S 1 consists of two driven unheated godets, while system S 2 consists of three heated driven godets that run at a higher speed in accordance with the stretch ratio. The process-relevant thread tensions are measured at the indicated points using an electronic thread tension meter.

Fig. 3 shows force-strain diagrams for a cop yarn produced conventionally in a two-stage process and a POY produced by the high-speed spinning process without godet stretching. The modulus parameter, reference force at 10% elongation (T 10), is defined on the basis of the figure.

Fig. 4 shows the influence of the variation of the stretch ratio on the force-elongation behavior. At a stretch ratio of 1.30, a cop-like stretch of about 40% is achieved. However, the modulus is low at T 10 = 19 cN/tex, so that this yarn is preferably used for the manufacture of knitted articles in the clothing sector. By increasing the stretch ratio, a desired higher value of T 10 can be achieved.

Fig. 5 shows the influence of the variation of the temperature of the system S 2 according to Example 2 on the shrinkage properties (boiling shrinkage, hot air shrinkage) of the yarn. At temperatures greater than or equal to 130°C, a noticeable reduction in these values occurs, while at the same time the thread shortening after winding is reduced to such an extent that stable bobbins with good bobbin structure can be produced.

The thread characteristics given for the description of the invention and in the examples were determined using the following measuring methods:

Titer

Measuring device: Yarn weight, pre-tension = 0.1 g/dtex

Strand weight G(g)

Strand length L = 50 m

Titre (dtex) = G x 10 000/L

Tear strength, elongation at break, T 10

Measuring device: TEXTECHNO Statimat II from Stein

Clamping length = 500 mm

Pre-tension = 0.1 g/dtex

average tear time = 20 +/- 2 sec

Breaking load and reference force are divided by the titre and given as tear strength and T 10 value according to Fig. 3.

Uster

Measuring device: Uniformity tester, model C, from Zellweger AG, Uster/Switzerland

Material speed = 100 m/min

Measuring range = 12.5%

Sensitivity = half inert or normal

Diagram feed = 5 cm/min

Cooking shrinkage

Measurement on the strand of total titre 2500 dtex,

Initial length under load of 500 g/2500 dtex = L[deep]V

Residence time in boiling water = 10 min,

and then 2 hours of conditioning (without load),

Strand length under above load after thermal treatment = L[deep]N

Cooking shrinkage (%) =

Hot air shrink

Measurement on the strand of total titre 2500 dtex,

Initial length under load of 500 g/2500 dtex = L[deep]V

Drying cabinet treatment at a temperature of 160 +/- 1°C and a dwell time of 20 min and subsequent conditioning for 30 min (without load),

Strand length under above load after thermal treatment = L[deep]N

Hot air shrinkage (%) =

Hot air shrinkage under load

Measurement as for hot air shrinkage, but oven treatment under a load of 0.2 g/dtex.

Permanent elongation at 2.0 g/dtex

Measuring device: TEXTURMAT from Stein,

Measurement on the strand of total titre 2500 dtex,

Measurement of the initial length under load of 2.5 g/2500 dtex (L[deep]V) Loading of the strand with a load weight corresponding to 2.0 g/dtex for a time of 10 sec

Measurement of strand length after treatment with a load of 2.5 g/2500 dtex (L[deep]N)

Permanent elongation (%) =

example 1

Under this designation, the properties of a nylon 6 cops yarn produced conventionally using the two-stage process are shown in the table as a comparative example.

Example 2

Nylon-6 polymer with a relative viscosity of n[low]rel = 2.40 was melted at 270°C in an extruder and spun at a rate of 38.9 g/min per die plate with 24 holes, each hole having a diameter of 0.25 mm.

In the subsequent blowing shaft, the melt threads were cooled by means of cross-flowing air at a speed of 0.5 m/sec. At a distance of 1500 mm from the nozzle plate, the cooled threads were treated with an oil/water emulsion using preparation nozzles, in such a quantity that the oil content of the wound thread was 0.6%.

The drawing unit with 5 godets corresponded to that of Fig. 2, whereby all godets were driven by motors and 2 godets with the same speed formed the spinning take-off system S 1 and 3 godets formed the drawing system S 2. The speed of S 1 was set at a constant 4282 m/min. The speed of S 2 was 5566 m/min, corresponding to a drawing ratio of 1:1.30. The winding speed was 5065 m/min, corresponding to a relaxation of 1:0.91. To heat the threads, the godet system S 2 was heated to a temperature of 180°C. In addition, the threads were passed through air turbulence nozzles directly before winding, by means of which a knotting of 20 knots/m was set in the yarn.

The measured thread tensions and textile-physical properties of the threads can be found in the table. The running properties and thread purity were excellent. The T 10 value is slightly lower than that of the cop yarn in example 1. However, the shrinkage behavior of the threads is more favorable than that of the cop yarn. These threads are preferably used in warp knitting.

Fig. 5 shows the corresponding shrinkage values for varying the temperature of system S 2. At temperatures greater than or equal to 130°C, extremely low shrinkage values and a stable bobbin structure without noticeable thread shortening on the bobbin are achieved.

Example 3 - 6

As in example 2, but the speeds of S 2 and the winder were increased step by step to increase the stretch ratio R 2. This resulted in a sharp increase in the thread tension in the stretching field F[deep]V. Since the tension F[deep]A could not be increased at the same time to achieve a good package build, correspondingly enlarged systems S 1 and S 2 were used. The corresponding wrap angles can be found in the table. In each case, the stretching was fixed in the systems S 1 and S 2.

With good running properties, high T 10 values that exceeded those of the cop yarn could be achieved. These yarns proved to be extremely stable and are preferred for woven goods with high requirements, e.g. sporting goods.

Example 7

As example 4, but instead of the godet heating of S 2, a heating plate of 400 mm length was used between system S 1 and S 2, as sketched in Fig. 2.

Example 8 - 9

Example 8 as Example 3, but the winder speed was reduced to set a lower relaxation of 1 : 0.86, i.e. R 4 = 0.86.

Due to the high tension ratio F[deep]VA = 11.1, constant stretching was not achieved. Only the use of an additional godet in system S 2 led to a stable stretching process (Example 9).

However, the high relaxation resulted in a significant reduction in the T 10 value. At the same time, the yarn elongated by more than 2% during the hot air shrinkage measurement and the irreversible elongation increased to more than 1%. Such specifications are considered inadmissible for suitable further processing behavior.

Example 10

Nylon 6 polymer as in the previous examples was melted in an extruder at a temperature of 266°C and spun at a rate of 23.2 g/min per spinneret plate having 10 holes, each hole having a diameter of 0.25 mm.

In the subsequent blowing shaft, the melt threads were cooled by means of cross-flowing air at a speed of 0.45 m/sec. At a distance of 1500 mm from the nozzle plate, the cooled threads were exposed to an oil/water emulsion using preparation nozzles, as in the previous examples.

The drawing unit with 5 godets corresponded to that of Fig. 2 and Example 2. The parameters set can be seen in the table. To heat the threads, a heating plate 400 mm long was installed instead of the godet system S 2 according to the system S 2. The running properties of this yarn type were also excellent.

Example 11

As in example 10, but the thread-air friction in the cooling area was increased by installing the preparation device at a distance of 3.5 m from the spinneret plate. This meant that the threads passed through the blowing and spinning shaft more openly. Due to the higher spinning tension that was created, the tension ratio F[deep]VS was reduced to 1.45, so that the system S 1 could be reduced by one godet.

Example 12 - 13

A conventional spinning and drawing system was used, in accordance with the specification 22 04 535. Systems S 1 and S 2 each consisted of just one godet with an associated, non-driven auxiliary roller. Both systems were wrapped several times by the threads, with S 1 wrapping five times and S 2 wrapping six times.

Under otherwise identical spinning conditions as in Example 10 and the same draw ratio, less favourable values of T 10 and/or hot air shrinkage under load and permanent elongation were measured in the threads. Almost twice as much fluff was measured and the number of full bobbins was

4% lower. When the stretch ratio was increased in Example 13, the textile-physical properties of the threads became more favorable, but the thread purity deteriorated drastically.

Example 14

Under this designation, the textile-physical properties of a polyester cops yarn produced conventionally using the two-stage process are shown in the table as a comparative example.

Example 15

Polyester polymer of viscosity n[tief]intr = 0.67 was melted at a temperature of 297°C in an extruder and spun at a rate of 28.4 g/min per spinneret plate with 24 holes, each hole having a diameter of 0.25 mm.

In the subsequent blowing shaft, the melt threads were cooled by means of cross-flowing air at a speed of 0.42 m/sec. At a distance of 1000 mm from the spinneret plate, the cooled threads were treated with an oil/water emulsion using preparation nozzles, in such a quantity that the oil content of the wound threads was 0.8%.

A conventional spinning and drawing system was used, as in example 12. The two godet systems were wrapped around several times by the threads, as in example 12. Setting the thread offset small alpha = 1° to avoid the threads touching proved to be very difficult and had to be readjusted from time to time. However, the thread path over the godets could not be set to be absolutely smooth under any circumstances. Rather, a fluctuation in the thread positions on the godets occurred in the transverse direction.

Example 16

The spinning conditions were set as in Example 15, but a drawing unit according to the invention was used as in Example 2. The godets of system S 1 were heated to 80°C and a heating plate was installed as heating device H after system S 2. The drawing conditions corresponded to those of Example 15.

Textile-mechanical characteristics of the threads were similar to cops. However, the shrinkage values were significantly lower. The running properties and the yarn purity were also significantly better than when using the drawing unit according to Example 15.

Example 17 - 19

Polyester of another polymer type with a viscosity n[tief]intr = 0.66 was melted at a temperature of 306°C in an extruder and spun at a rate of 25.0 g/min per spinneret plate with 34 holes, each hole having a diameter of 0.25 mm.

In the subsequent blowing shaft, the melt threads were cooled by means of cross-flowing air at a speed of 0.32 m/sec. At a distance of 910 mm from the nozzle plate, the cooled threads were treated with an oil/water emulsion using preparation nozzles, as in the previous example 16.

The stretching unit according to Example 16 was used, but instead of the heating device H, the godets of the system S 2 were used to heat the thread. The temperature of the system S 2 was then varied under constant stretching conditions. The shrinkage values of the threads determined show a strong dependence on the temperature. While excellently low shrinkage values were achieved at a set temperature of 180°C, these were already unacceptably high at a temperature of 100°C.

continuation continuation continuation continuation

Claims (3)

1. Process for producing highly oriented and crystallized smooth yarns made of polyester, polyamides or polypropylene in a one-step process by direct drawing, heat-setting and relaxation after spinning and before winding the yarns at a speed of at least 4500 m/min, wherein godets and thread deflection elements are used as the spinning take-off system and as the drawing system, each of which contains at least one godet driven by a motor, the speed ratio of the drawing system and the spinning take-off system is selected to be so high that orientation drawing takes place with a drawing tension that is at least 40% higher than the spinning tension before the threads enter the spinning take-off system and wherein the dimensions of the heating device causing the heat-setting are selected so that the thread residence time is at least 4 msec and the temperature is at least 130°C, characterized in that the godets and thread deflection elements of the spinning take-off system and the drawing system are arranged axially parallel to one another and are not offset from one another in depth and are meandered around by the yarns, that the thread offset from the spinning take-off system to the drawing system is a maximum of 0.15°, that the drawing tension is more than a factor of 3 higher than the tension between the drawing system and the winding unit and that the speed ratio R 4 between the winding unit and the outlet godet of the drawing system is 1.0 to 0.9. 2. Method according to claim 1, characterized in that the wrap angle around each godet is at least 90° and at most 270°, wherein the number M or N of godets or deflection elements for the spinning take-off system or the drawing system is selected such that their total wrap angle U as a function of the ratios of the thread tension F[deep]VS and F[deep]VA defined in the description and the total number of godets and deflection elements M + N is less than or equal to 10. 3. Method according to one of claims 1 or 2, characterized in that the speed ratios of the godets correspond to the following values: between the godets of the spinning take-off system R 1 = 1.0 to 1.06 Inlet godet of the stretching system to the outlet godet of the spinning take-off system R 2 = 1.06 to 2.0 between the godets of the stretching system: R 3 = 1.06 to 0.92 and the total stretch ratio R = R 1 x R 2 x R 3 x R 4 is between 1.06 and 1.84.