METHOD FOR PRODUCING A CRIMPED COMPOSITE THREAD

Abstract

The invention relates to a method and to a device for producing a crimped composite thread. The crimped composite thread includes a first polymer melt and a second polymer melt. The first polymer melt and the second polymer melt are arranged next to one another, in particular side-by-side, in portions in such a way that a composite thread is formed. The first polymer melt and the second polymer melt each have a different material property so that self-crimping of the composite thread is initiated by means of an active crimping initiation. Additionally, there is a system for producing a crimped composite thread from a bulk continuous filament yarn for carpet yarn using the method and the device.

Claims

1. Method for producing a crimped composite thread, wherein the crimped composite thread has a plurality of composite filaments from a first polymer melt and a second polymer melt, wherein the first and the second polymer melt are arranged next to one another, side-by-side, in portions in such a way that a composite thread is formed, wherein the first polymer melt and the second polymer melt each have a different material property so that self-crimping of the composite thread is initiated open-loop and/or closed-loop controlled by an active crimping initiation at a predetermined point in the method.

2. Method according to claim 1, wherein the active crimping initiation of self-crimping is mechanically initiated by applying a predetermined tension variable to the composite thread, wherein a predetermined tensile stress is applied to the composite thread.

3. Method according to claim 1, wherein the active crimping initiation of self-crimping is thermally initiated by heating, wherein a predetermined temperature variable is applied to the composite thread.

4. Method according to claim 1, wherein the composite thread is configured to be trilobal in shape, and/or each trilobal portion has in each case a first, a second and/or a third polymer melt.

5. Method according to claim 1, wherein the first polymer melt has a different viscosity than the second polymer melt.

6. Method according to claim 1, wherein the tensile stress on the composite thread is initiated by means of a drafting unit, wherein a tensile stress, in the range from 1 to 4.5 cN/dtex, which reaches a predetermined threshold value that initiates self-crimping is applied to the composite thread by means of the drafting unit, wherein the variable of the threshold value determines the degree of self-crimping.

7. Method according to claim 1, wherein the tensile stress which, for initiating self-crimping, is applied to the composite thread by means of a drafting unit is greater than a tension which is applied to the composite thread for drafting by a drafting unit.

8. Method according to claim 1, wherein self-crimping of the composite thread is initiated by means of heating by means of a heating installation, wherein self-crimping is initiated at a predetermined temperature variable in the composite thread, at a temperature variable in the range from 100 to 150 C., wherein the variable of the temperature determines the degree of self-crimping.

9. Method according to claim 1, wherein the first polymer melt and the second polymer melt are extruded in a melt-spinning device and spun so as to form a plurality of composite filaments which are cooled so as to form a partially crystalline structure and are converged at a convergence point so as to form a composite thread which is drafted in a first drafting device so as to form a preliminary drafted composite thread, wherein self-crimping in the composite thread is initiated in subsequent steps by applying a predetermined tension variable and/or a predetermined temperature variable so that a crimped composite thread is formed.

10. Method according to claim 1, wherein the active crimping initiation of self-crimping of the composite thread is initiated before and/or after compression-crimping, wherein the composite thread during compression-crimping is compressed in the thread running direction in a compression-crimping installation, wherein the compression of the composite thread initiates crimping.

11. Device for producing a crimped composite thread, which is specified for carrying out a method for producing the crimped composite thread, in which the crimped composite thread has a plurality of composite filaments from a first polymer melt and a second polymer melt, wherein the first and the second polymer melt are arranged next to one another, side-by-side, in portions in such a way that a composite thread is formed, wherein the first polymer melt and the second polymer melt each have a different material property so that self-crimping of the composite thread is initiated open-loop and/or closed-loop controlled by an active crimping initiation at a predetermined point in the method, and wherein the device has an installation for the active initiation of self-crimping of the composite thread.

12. Device according to claim 11, wherein the installation for the active initiation of self-crimping has a drafting device for generating tensile stress in the composite thread, and/or has a heating installation for generating an increase in temperature in the composite thread.

13. System for producing a crimped composite thread from a bulk continuous filament yarn for carpet yarn, which is specified for carrying out a method for producing the crimped composite thread, in which the crimped composite thread has a plurality of composite filaments from a first polymer melt and a second polymer melt, wherein the first and the second polymer melt are arranged next to one another, side-by-side, in portions in such a way that a composite thread is formed, wherein the first polymer melt and the second polymer melt each have a different material property so that self-crimping of the composite thread is initiated open-loop and/or closed-loop controlled by an active crimping initiation at a predetermined point in the method.

14. System as in claim 13 wherein the device has an installation for the active initiation of self-crimping of the composite thread.

15. System as in claim 14 wherein the installation for the active initiation of self-crimping has a drafting device for generating tensile stress in the composite thread, and/or has a heating installation for generating an increase in temperature in the composite thread.

Description

[0060] In the figures:

[0061] FIG. 1 schematically shows a device for producing a crimped composite thread without actively initiated self-crimping;

[0062] FIG. 2 schematically shows a first exemplary embodiment of a device and of a method for producing a crimped composite thread, having actively mechanically initiated self-crimping by means of an additional drafting unit which causes mechanical drafting on the composite thread;

[0063] FIG. 3 schematically shows a second exemplary embodiment of the device and of the method for producing a crimped composite thread, having actively mechanically initiated self-crimping by means of an additional godet pair which is positioned in front of a cooling drum and causes mechanical drafting on the composite thread;

[0064] FIG. 4 schematically shows a third exemplary embodiment of the device and of the method for producing a crimped composite thread, having actively mechanically initiated self-crimping by means of an additional godet pair which is positioned after the cooling drum and causes mechanical drafting on the composite thread;

[0065] FIG. 5 schematically shows a fourth exemplary embodiment of the device and of the method for producing a crimped composite thread, having actively mechanically initiated self-crimping by means of a thread brake which is positioned after the cooling drum and causes mechanical drafting on the composite thread;

[0066] FIG. 6 schematically shows a fifth exemplary embodiment of the device and of the method for producing a crimped composite thread, having actively thermally initiated self-crimping by means of a heating installation which is positioned at the cooling drum and causes a thermal treatment on the composite thread;

[0067] FIG. 7 schematically shows a sixth exemplary embodiment of the device and of the method for producing a crimped composite thread, having actively thermally initiated self-crimping by means of a heating installation which is positioned after the cooling drum and causes a thermal treatment on the composite thread; and

[0068] FIG. 8 schematically shows a block diagram of the method steps for producing a crimped composite thread, wherein self-crimping of the composite thread is initiated mechanically or thermally, or mechanically and thermally, by means of an active crimping initiation.

[0069] FIG. 1 shows a device for producing a crimped composite thread KKF, without actively initiated self-crimping.

[0070] The composite thread KF is usually spun from at least a first polymer melt 80 and a second polymer melt 81 next to one another by means of a melt-spinning device 2, so that the composite thread KF is formed with at least two portions.

[0071] Thereafter, drafting takes place in a drafting step D1 in which orienting the previously randomly arranged chain molecules so as to form oriented chain molecules is performed.

[0072] Mechanically applied crimping can then be caused by means of a compression-texturising installation 22, in that the composite thread KF is compressed in a compression chamber of the compression-texturising installation 22 in such a way that a loop yarn is created, whereby the filaments of the composite thread KF are kinked, this causing texturising, or crimping, of the composite thread KF.

[0073] The composite thread KF can thereafter be deposited onto a cooling drum 12, or cooling roller 12, so that the internal temperature of the composite thread KF is below the glass transition temperature and the texturising previously generated, hereunder also referred to as crimping, is set.

[0074] In the device having the compression-texturising installation 22 shown in FIG. 1, the crimping is formed in step T1, whereby the composite thread KF is compressed so as to form a plug in the compression-texturising installation 22, this leading to crimping of the composite thread KF.

[0075] The device shown in FIG. 1 has a first polymer store 30 in which plastics material chips of a first polymer 80 are stored, and a second polymer store 32 in which plastics material chips of a second polymer 81 are stored.

[0076] The two, or the plurality of, polymers can be of the same polymer type (e.g. two PETs with different proportions of IV and/or TiO.sub.2), or be different polymer types (e.g. PET and PTT). The polymer combination of the composite thread KF is chosen in such a way that self-crimping of the composite thread KF can be initiated by introducing tensile stress and/or temperature into the composite thread KF.

[0077] The plastics material chips of the first and of the second polymer store 30, 32 are in each case separately processed in a first extruder 1.1 and a second extruder 1.2 so as to form a first and a second polymer melt 80, 81, and are supplied by way of a separate melt line 34 to a melt-spinning device 2 by means of a first and a second melt pump 36, 36.

[0078] The first and the second polymer melt are arranged next to one another, in particular side-by-side, in portions above capillaries so as to form a thread in such a way that a composite thread KF is formed. The composite threads can be combined at a convergence point 44 so as to form a thread F.

[0079] After the convergence point 44, the composite thread KF is preferably guided over a preparation installation 4 and provided with a preparation agent. The preparation agent minimises friction, ensures static discharging, and facilitates transportation of the composite thread KF.

[0080] The thread running direction F runs from the melt-spinning installation 2 towards a take-up winding device 20.

[0081] In a first drafting zone D1, or in a first drafting step D1, the composite threads KF are drawn from the melt-spinning installation 2 by means of an inlet unit 6 having an idler roller 60 and a godet 61, and are drafted by a first drafting unit 8 and a second drafting unit 10, each consisting of one godet pair.

[0082] After the drafting step D1, in a texturising step T1, the composite thread is compressed in a compression-texturising installation 22, as a result of which the composite thread KF is crimped by compression.

[0083] After the texturising step T1, the composite thread KF is guided over a cooling drum 12, whereby the composite thread KF is cooled to a predetermined temperature in a cooling zone C1.

[0084] After the cooling step in the cooling zone C1, relaxing takes place in a relaxing zone R1. In the process, the crimped composite thread KKF is also interlaced by means of an interlacing installation 18 in such a way that entanglement knots are formed in the crimped composite thread KKF, so that the crimped composite threads KKF remain permanently combined and held so as to form an overall thread.

[0085] The relaxing zone R1 has a first relaxing unit 14 and a second relaxing unit 16. The interlacing installation 18 is preferably positioned between the first relaxing unit 14 and the second relaxing unit 16.

[0086] The drafted, texturised and relaxed overall thread is thereafter wound in a take-up winding device 20 so as to form a package for further processing such as, for example, to form a carpet.

[0087] Exemplary embodiments of the device according to the invention and of the method according to the invention for producing a crimped composite thread KKF with actively initiated self-crimping SK are described in FIGS. 2 to 8 hereunder. The features that are relevant for the actively initiated self-crimping SK are in particular described in the description hereunder.

[0088] The crimped composite thread KKF of the exemplary embodiments described in FIGS. 2 to 8 has a proportion of crimping by self-crimping SK, and a proportion of crimping by compression-texturising T1. The proportion of crimping by self-crimping SK is better in terms of quality than the proportion of crimping by compression-texturising T1.

[0089] The features described in FIG. 1 with the same reference signs are also identical in the device according to the invention and in the method according to the invention from FIGS. 2 to 7.

[0090] However, not all features of the exemplary embodiments shown in FIGS. 2 to 8 are required.

[0091] Described in FIGS. 2 to 8 are exemplary embodiments in which the overall crimping of the crimped composite thread KKF includes both compression-crimping T1, formed by the compression-texturising installation 22, as well as actively mechanically or thermally initiated self-crimping SK.

[0092] The mechanically actively initiated self-crimping SK is initiated by means of tensile stress with a predetermined variable, which is applied to the composite thread KF by means of additional godets, this being indicated by the reference sign SK which indicates the position of the mechanical active initiation of self-crimping SK in the respective exemplary embodiments of the device, or in the respective exemplary embodiments of the method, in FIGS. 2 to 5. The variable of the tensile stress can determine the degree of self-crimping SK.

[0093] The thermally actively initiated self-crimping is initiated by an additional heating installation 50 which acts on the composite thread KF, this being indicated by the reference sign SK which indicates the position of the thermal initiation of self-crimping SK in the respective exemplary embodiments of the device, or in the respective exemplary embodiments of the method, in FIGS. 6 to 7. The variable of the temperature can determine the degree of self-crimping SK.

[0094] Self-crimping SK of the composite thread KF can advantageously be initiated at any arbitrary position within the production process, or within the device of FIGS. 2 to 7, depending on where the mechanical and/or thermal activation of self-crimping SK is carried out in the succession of the respective steps.

[0095] In other words, self-crimping SK can be initiated by mechanical and/or thermal activation at a predetermined position with the device. The initiation of self-crimping SK can take place with mechanical and/or thermal means, also by means of the compression-texturising installation 22 as illustrated in the exemplary embodiments in FIGS. 2 to 7. There is no separate compression-texturising T1 by the compression-texturising installation 22 in the process. The compression-texturising installation 22 may also be omitted.

[0096] The invention comprises a method and a device for producing a very intensely self-crimping composite thread KF from at least two, or a plurality of, polymers 80, 81. The activatable self-crimping SK of the composite thread KF improves the quality of crimping. Moreover, polymer melt 80, 81 can be effectively saved in the process, as a result of which a composite thread KKF with improved crimping quality can be produced with less material.

[0097] Particularly effective crimping of the composite thread KF is possible by means of the devices described hereunder, whereby a smaller quantity of the respective polymer melt is simultaneously required in the process.

[0098] FIG. 2 shows a first exemplary embodiment of the method and of the device for producing a crimped composite thread KKF which by means of active crimping initiation is animated to self-crimping SK its composite thread KF.

[0099] The components and features with the identical reference signs from FIG. 1 correspond to the components and features of the exemplary embodiments of the device and of the method for producing a crimped composite thread KKF described in FIGS. 2 to 7 hereunder, whereby the crimped composite thread KKF had actively activatable self-crimping SK.

[0100] The features and devices of the method according to the invention and of the device according to the invention are described in particular hereunder, said features and devices potentially also being part of the device of FIG. 1 and having new features and components of the installations for initiating the actively activatable self-crimping SK.

[0101] The method shown in FIG. 2, and the device shown, additionally has a second drafting zone D2 for initiating self-crimping SK. The drafting zone D2 additionally has a third drafting unit 40 which has an idler roller 60 and a godet 61, like the inlet unit 6 which only draws the composite thread KF from the melt-spinning device 2 in the thread running direction F.

[0102] A further embodiment is shown drawn with dashed lines in FIG. 2, whereby the second drafting zone has a third and a fourth drafting unit 40.1 and 40.2.

[0103] The third, and the fourth, drafting unit 40.1, 40.2 are adjusted in such a manner that a predetermined tensile stress acts on the composite thread KF, said tensile stress causing corresponding self-crimping SK of the composite thread KF.

[0104] In order for the self-crimping property to be effective, a first polymer melt 80 and a second polymer melt 81 with different viscosities are in each case supplied at different flow rates to the melt-spinning installation 2 by way of the first and the second extruder 1.1 and 1.2 and the associated melt lines 34, said melt-spinning installation 2 by way of its capillaries and spinning nozzles then generating a side-by-side composite thread KF which has the properties of activatable self-crimping SK

[0105] FIG. 3 schematically shows a second exemplary embodiment of the device and of the method for producing a crimped composite thread KKF with actively mechanically initiated self-crimping SK by means of an additional godet pair 42 positioned in front of the cooling drum.

[0106] The godet pair 42 is able to be assigned to a third drafting unit 42, and has a first and a second godet 71, 72. The third drafting unit 42 is positioned in a second drafting zone D2 for carrying out a second drafting step D2, which causes additional mechanical drafting on the composite thread KF and leads to self-crimping SK being initiated.

[0107] The crimped composite thread KKF in the thread running direction F in the relaxing zone R1 is thereafter additionally compression-crimped T1 in the compression-texturising installation 22, and thereafter cooled in a cooling step C1 at the cooling drum 12.

[0108] In further steps, the self-crimped and the compression-crimped composite thread KKF is relaxed in a first relaxing unit 14 and a second relaxing unit 16, and is provided with entanglement knots in an interlacing installation 18. The interlacing installation 18 is positioned between the first and the second relaxing unit 14, 16.

[0109] The first relaxing unit 14 and the second relaxing unit 16 each have an idler roller 60 and a godet 61.

[0110] The godets 71, 72, 61 can be heated and/or not heated. In this way, further temperature-controlling is possible in the method and can be closed-loop controlled so as to correspond to the polymers used and preferably be performed according to the degree of crimping, right down to room temperature.

[0111] Initiating self-crimping SK in the composite thread KF at the respective position can optionally also be activated and initiated by way of the heated godets 71, 72 and 61.

[0112] The activated self-crimping SK by mechanical drafting can be provided with associated sensors which detect the tensile stress introduced into the composite thread KF and the initiated self-crimping SK in such a way that it is possible to closed-loop control self-crimping and the degree of self-crimping SK.

[0113] FIG. 4 schematically shows a third exemplary embodiment of the device and of the method for producing a crimped composite thread KKF with actively mechanically initiated self-crimping SK by means of an additional godet pair 42.1, or 42.2, which is positioned after the cooling drum 12 and causes mechanical drafting on the composite thread KF. The additional godet pair 42.1, or 42.2, defines a second drafting zone D2. The drafting zone D2 may also have only one godet pair 42.1.

[0114] The godet pair 42.1, illustrated by dashed lines, is optional.

[0115] The respective godet pair 42.1, or 42.2, can also be heated so that thermal activation of self-crimping SK of the composite thread KF is also possible besides the mechanical activation of self-crimping SK.

[0116] The second drafting zone D2 subdivides the relaxing zone R into a first relaxing zone R1 and into a second relaxing zone R2.

[0117] The first relaxing zone R1 has the compression-texturising installation 22 and the cooling drum 12, which are disposed behind one another in the thread running direction F.

[0118] The first relaxing zone R2 has the first relaxing unit 14 and the second relaxing unit 16 and the interlacing installation 18. The interlacing installation 18 in the thread running direction F is positioned between the first relaxing unit 14 and the second relaxing unit 18.

[0119] FIG. 5 schematically shows a fourth exemplary embodiment of the device and of the method for producing a crimped composite thread KKF with actively mechanically initiated self-crimping SK by means of a thread brake 90 which is positioned after the cooling drum 12 in the thread running direction F and causes mechanical drafting on the composite thread KF, thus activating and initiating self-crimping SK.

[0120] The exemplary embodiment shown in FIG. 5 is identical to the exemplary embodiment shown in FIG. 4, with the exception that a thread brake 90 for initiating mechanical self-crimping SK is provided instead of the godet pair 42.1, or 42.2, in the second drafting zone D2.

[0121] FIG. 6 schematically shows a fifth exemplary embodiment of the device and of the method for producing a crimped composite thread KKF with actively thermally initiated self-crimping SK by means of a heating installation 50 which is positioned at the cooling drum 12 and causes a thermal treatment on the composite thread KF.

[0122] The heating installation 50 incorporates into the composite thread a predetermined temperature in the range from 100 to 150 C., which causes initiation of self-crimping SK. The variable of the incorporated temperature can also determine the degree of self-crimping SK. The heating installation 50 can be provided with associated sensors which detect the temperature incorporated into the composite thread KF and the initiated self-crimping SK in such a way that it is possible to closed-loop control self-crimping and the degree of self-crimping SK.

[0123] FIG. 7 schematically shows a sixth exemplary embodiment of the device and of the method for producing a crimped composite thread KKF with actively thermally initiated self-crimping SK by means of a heating installation 50 which in the thread running direction F is positioned after the cooling drum 12 and causes a thermal treatment on the composite thread KF.

[0124] The heating installation 50 can be provided with associated sensors which detect the temperature incorporated into the composite thread KF and the initiated self-crimping SK in such a way that it is possible to closed-loop control self-crimping and the degree of self-crimping SK.

[0125] The exemplary embodiments shown in FIGS. 6 and 7 are identical to the exemplary embodiment shown in FIG. 4, with the exception that a heating zone H1 for initiating self-crimping SK is provided instead of the second drafting zone D2.

[0126] The exemplary embodiments proposed here, and the drafting zones D2 and heating zones H1 shown therein for initiating self-crimping SK, can also be combined with one another. In this way, the method and the device may also have a drafting zone D2 and a heating zone H1.

[0127] FIG. 8 schematically shows a block diagram of the method steps for producing a crimped composite thread KKF, whereby self-crimping SK of the composite thread KF is initiated mechanically or thermally, and/or mechanically and thermally, by means of active crimping initiation.

[0128] In a particularly preferred exemplary embodiment of the method, the first polymer melt 80 and the second polymer melt 81 are extruded in the melt-spinning device 2 in step S1, and in step S2 spun so as to form a plurality of composite filaments.

[0129] The number of capillaries in the melt-spinning device 2 determines the number of composite filaments.

[0130] In step S3, the plurality of composite filaments are cooled so as to form a partially crystalline structure. Cooling can be carried out by transverse and/or radial cooling in suitably specified cooling ducts, with air guided transversely to and/or in the thread running direction F.

[0131] In step S4, the plurality of composite filaments are combined at the convergence point 44 so as to form a composite thread KF.

[0132] In step S5, the combined composite thread KF is provided with a preparation oil in a preparation installation 4, which improves friction and processing of the composite thread KF and prevents, or at least minimises, static charging of the composite thread KF.

[0133] In a first drafting step D1, preliminary drafting of the composite thread KF by the first drafting device 6, 8, 10 takes place in step S6.

[0134] After drafting, compression-texturising, or compression-crimping T1, by the compression-texturising installation 22 can take place in step S7. In the process, the composite thread KF is crimped by compression T1 and compressed so as to form a plug.

[0135] In step S8, the plug is cooled on the cooling drum 12 in a cooling step C1.

[0136] In step S9, the plug is drafted and relaxed in a relaxing step R1 so as form a composite thread KF that is able to be entangled, and provided with entanglement knots which combine and hold together the filaments of the crimped composite thread KKF for further processing.

[0137] Finally, the relaxed and entangled composite thread KKF is wound so as to form a wound package by means of a take-up winding device 20 in step S10.

[0138] The activation of self-crimping SK by applying a predetermined mechanical tensile stress variable in a second drafting step D2, and/or by applying a predetermined temperature variable in a heating step H1, preferably takes place before, during and/or after cooling step C1.

[0139] Shown in FIGS. 2, 4 and 5 are exemplary embodiments in which, in addition to compression-crimping T1, self-crimping SK of the composite thread KF is activated and initiated by a suitable drafting device 40.2, 42.1, 42.2 in a second drafting step D2 on account of an applied tensile stress variable in the composite thread KF, once the composite thread KF has been cooled on the cooling drum 12 in cooling step C1.

[0140] Shown in FIG. 3 is an exemplary embodiment in which, in addition to compression-crimping, self-crimping SK of the composite thread KF is activated and initiated by suitable drafting devices 42 in a second drafting step D2 on account of an applied tensile stress variable in the composite thread KF, before the composite thread is cooled on the cooling drum 12 in cooling step C1.

[0141] In the exemplary embodiment shown in FIG. 3, compression-crimping T1 additionally takes place by means of the compression-texturising installation 22 before cooling step C1 but after self-crimping SK.

[0142] Shown in FIGS. 6 and 7 are exemplary embodiments in which initiating self-crimping SK is thermally caused in cooling step C1 at the cooling drum 12, and/or after cooling step C1 at the cooling drum 12, by means of heating H1, whereby a predetermined temperature variable is applied to the composite thread by the heating installation 50 which is additionally positioned in the thread run.

[0143] Self-crimping SK can also be initiated and activated at other positions of the device in the thread running direction F, and in other method steps in the production method.

[0144] In an exemplary embodiment not illustrated, the activation of self-crimping SK is only mechanical or thermal, or mechanical and thermal, and no compression-crimping is necessary.

LIST OF REFERENCE SIGNS

[0145] 1 Extruder [0146] 1.1 First extruder [0147] 1.2 Second extruder [0148] 2 Melt-spinning device [0149] 4 Preparation installation [0150] 6 Inlet unit [0151] 8 [0152] 00 First drafting unit [0153] 10 Second drafting unit [0154] 12 Cooling drum [0155] 14 First relaxation unit [0156] 16 Second relaxation unit [0157] 18 Interlacing installation [0158] 20 Take-up winding device [0159] 22 Compression-texturising installation [0160] 30 First polymer store [0161] 32 Second polymer store [0162] 34 Melt line [0163] 36, 36 First melt pump, second melt pump [0164] 40, 40.1 Third drafting unit [0165] 40.2 Fourth drafting unit [0166] 42 Third drafting unit [0167] 42.1 Third drafting unit [0168] 42.2 Fourth drafting unit [0169] 44 Convergence point [0170] 50 Heating installation [0171] 60 Idler roller [0172] 61 Godet [0173] 70 Godet pair [0174] 71, 72 First godet, second godet [0175] 80, 81 First polymer melt, second polymer melt [0176] 90 Thread brake [0177] C1 Cooling zone/cooling step [0178] D1 First drafting zone/first drafting step [0179] D2 Second drafting zone/second drafting step [0180] R1 First relaxing zone/first relaxing step [0181] R2 Second relaxing zone/second relaxing step [0182] F Thread running direction [0183] KF Composite thread, bi-component thread [0184] KKF Crimped composite thread [0185] SK Self-crimping position/self-crimping step [0186] T1 Compression-crimping [0187] H1 Heating zone, heating step