EP1115926A1

EP1115926A1 - Threads made of polymer blend fibers or filaments based on polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate, and the use thereof

Info

Publication number: EP1115926A1
Application number: EP99947344A
Authority: EP
Inventors: Claudia Fritz; Peter Hirt; Wilhelm Oppermann; Winfried Schuler; Karl-Heinrich Wiese
Original assignee: Deutsche Institute fuer Textil und Faserforschung Stuttgart
Current assignee: Deutsche Institute fuer Textil und Faserforschung Stuttgart
Priority date: 1998-09-14
Filing date: 1999-09-14
Publication date: 2001-07-18
Also published as: DE19944029C2; AU6082999A; WO2000015886A1; DE19944029A1

Abstract

The invention relates to threads made of polymer blend fibers or filaments comprising the blend components: 1) polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) and 2) polytrimethylene terephthalate (PTT) in a blend ratio 1):2) ranging from approximately 5:95 to 95:5, especially ranging from approximately 10:90 to 90:10. The inventive threads are characterized in that the fibers or filaments of the threads have breaking elongations ranging from 15 to 35 % after one or several drawing processes and, after elongation cycles-fiber-tests with 5 % total elongation, they have smaller permanent elongations εR than the permanent elongation εR calculated for the first elongation cycle using the equation εR [%] = 0.61 (0.59/100) • X, calculated for the fifth elongation cycle using the equation εR [%] = 0.69 (0.67/100) • X and calculated for the tenth elongation cycle using the equation εR [%] = 0.67 (0.65/100) • X. In these equations, the variable x represents the weight percentile portion of PTT ranging from approximately 5 to 95 % in the PET-PTT blend fibers or filaments or PBT-PTT blend fibers or filaments. The threads exhibit a) no twisting, b) a protection against twisting with a metric twist coefficient α ranging from 0.2 to 10, or c) with a standard twist, a twist coefficient α of up to 130. The standard specification DIN 53832 is valid for the twist coefficient α, α = (t/m•∑(dtex))/100 is defined, t/m represents the number of twists per meter, and dtex represents the fineness of the fibers or filaments. The invention also relates to advantageous uses of these threads especially for producing carpets, knitted fabrics, woven fabrics, nonwoven fabrics, or felts. The threads are advantageous in that a low level of permanent elongation results after cyclical elongation strains and they do not have a tendency to snarl or frizz.

Description

Yarns made from polymer blend fibers or filaments based on polyethylene, polybutylene and polytrimethylene terephthalate and their use

The invention relates to yarns made from polymer blend fibers or filaments, comprising the blend components 1) polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) and 2) polytrimethylene terephthalate (PTT) in a mixing ratio of 1): 2) of about 5:95 to 95: 5, in particular from about 10:90 to 90:10, and their use as undyed or dyed yarns for textile fabrics, in particular carpets, knitted fabrics, fabrics, nonwovens or felts.

The syntheses of PET and PBT have been known for a long time and are carried out on an industrial scale using the DMT and the preferred TPA process. The necessary spinning technologies and knowledge of the fiber properties are also state of the art.

Due to the newer synthetic routes to 1,3-propanediol by Shell Chemical Comp. (USA), Degussa AG (DE), the PTT is more accessible on a large industrial scale as a fiber raw material. The synthesis of the PTT is similar to that of the PET and PBT. More recent information on the PTT fiber properties can be found in W. Oppermann et al. (Lecture, "fibers of polytrimethylene terephthalate", 34th Internat. DORNBIRN-MFC (A), 20.- 22.09.1995) and H. Chuah (Chemical Fibers International 46 (1996), 424-428) to the fin ^¬. EP 0 746 648 B1 discloses the pressure-free and carrier-free dyeability of PTT fibers with disperse dyes in an aqueous liquor.

Chemical and physical modifications were made at an early stage in order to achieve special property profiles for PET and PBT fibers:

H. Büttner (Angew. Makromol. Chem. 40/41 (1974), 57-70) describes the Modifizie ^¬ tion of PET and PBT as the fiber raw materials for improved dyeability of the fibers. The physical modification of the fibers through the use of polymer mixtures made of PET and PBT is described in detail by R. Gutmann et al. (Chemical fibers / textile industry 37/89 (1987), 144-150; 37/89 (1987), 806-814: 40/92 (1990), 104-109; J. Appl. Polym. Sc.: Appl. Polym. Symp. 47 (1991), 199-221).

Due to their macromolecular structure, textile fibers exhibit both elastic and viscoelastic behavior (flow behavior) when subjected to tensile stresses in the direction of their fiber axis. For the usage properties i.a. the dimensional stability and recovery of the fibers is this behavior in textile fabrics, e.g. of particular importance for carpets.

For the assessment, the fibers are subjected to a single or multiple tensile stress and relief between constant elongation limits - an elongation cycle. The residual strain εR (also called permanent strain) and the elastic strain εi can be determined, whereby the following relationship exists between these strains and the total strain εc used for the respective strain cycle: ER = εσ - εi.

If the elongation information is given as a percentage, this refers to the test length of the fiber equal to 100%, whereby the fiber is under a titer-dependent pretensioning force (here 0.25 cN / tex). Due to the time-dependent relaxation processes in the fibers, after the tensile stress has been released and relieved, waiting times to be defined between the cycles - here: 5 minutes - must be observed before measuring the permanent strains.

The results of such measurements were reported by IM Ward et al. (J. Polym. Sei., Polym.Phys. Ed. 14 (1976), 263-274) for PET, PBT and PTT fibers are discussed and published. The following gradations for the permanent strains are given: PET>PBT> PTT. _ΛÄ „, _oo PCT / EP99 / 06796

WO 00/15886

These differences are interpreted by the molecular conformations in the crystalline and non-crystalline areas of the unmodified fibers. So I.M. Ward et al. in an earlier publication (J. Polym. Sei. Polym. Phys. Ed. 13 (1975), 799) described the reversible expansion of the crystalline regions in the PTT by the rotation of the methylene groups from a gauche-gauche conformation towards a trans-con formation, which is however not reached, explained.

W. Oppermarm (see above) and H also refer to the good recovery of PTT fibers, as evidenced by cyclical elongation stresses between constant tensile force limits. Traub et al. (Chem. Fibers Int. 45, (1995), 110). Further information on elastic elongation in PA 6, PA 6.6 and PET fibers can be found in B. von Falkai ("Synthesefaser". Verlag Chemie. Weinheim 1981, ISBN 3-527-25824-8, p. 449; information on measurement technology on page 409).

The aforementioned information on the residual elongation SR relates to fibers which are produced from unmodified PET, PBT and PTT. Mixtures of PTT with PET and PTT with PBT are addressed in US-A-4,410,473, US-A-4,454,196 and US-A-4,475,330. US Pat. No. 4,475,330 is concerned only with the production of high-twisted yarns using fibers or filaments of the polymers mentioned and their mixtures. that can be realized via a certain fixing process. The in the US

A-4 475 330 described high twisted yarns have the disadvantage that they are unsuitable for fabrics in which no crepe effect is desired. US-A-4 410 473 and US-A-4 454 196 aim to incorporate polymers based on styrene, methyl acrylates or acrylates to produce certain multifilament yarns. Neither of these U.S. patents, nor any other publication, discloses a technical teaching of how to be reduced or maintained at the low level of residual elongation of the PTT fibers while maintaining carrier free dyeability through physical modification, particularly through the use of polymer blends, which affects residual elongation after tensile stress can. The invention is therefore based on the object to provide yarns of the type initially described _^ are available which do not show the described disadvantages of the prior art and have improved properties, particularly excellent repetition after deformations or elongations.

This object is achieved according to the invention by yarns made from polymer blend fibers, comprising the blend components polyethylene terephthalate (PET) and polytrimethylene terephthalate (PTT) in a weight ratio of from about 5:95 to about 95: 5, preferably from about 10:90 to about 90:10, characterized in that are that the fibers or filaments of the yarns have an elongation at break of 15 to 35% after one or more stretching processes and that after elongation cycle fiber tests with 5% total elongation have smaller residual elongations SR than those for the first elongation cycle due to the Equation ε _R [%] = 0.61 - (0.59 / 100) • X, for the fifth stretch cycle by the equation ε _R [%] = 0.69 - (0.67 / 100) • X and for the tenth strain cycle using the equation ε _R [%] = 0.67 - (0.65 / 100) • X calculated residual elongation S _R , where in these equations the variable X represents the percentage by weight of the PTT of about 5 to 95% in the PET-PTT blend fibers or filaments or PBT-PTT blend fibers or filaments, the yarns a) having no twist, b) a protective twist with a metric twist factor α of 0.2 to 10 or c) with standard twist having a twist factor α up to 130 , where the rotation coefficient α according to DIN 53832 as α = (t / m • ) / 100 is defined, with t / m the number of twists per meter and dtex the fineness of the fibers or filaments. The "twist parameter" K used in US-A-4,475,330 is defined as K = (t / m) • 95 x α (see dtex Römpp Chemie Lexikon, 9th edition, vol. 6, p. 4538).

The invention also relates in particular to yarns of the type described above, which are characterized in that the fibers or filaments after stretching cycle fiber tests, in a change from 5% to 10% total stretch, have smaller residual strains ε _R than those for the first Strain cycle through the equation ε _R [%] = 3.36 - (3.34 / 100) • X, for the fifth stretch cycle using the equation « _R [%] = 4, 16 - (4, 14/100) • X and for the tenth Elongation cycle by the equation ε _R [%] = 4.42 - (4.40 / 100) • X calculated residual elongation ε _R , where in these equations the variable X is the weight percentage of the PTT of about 60 to 95% in the PET -PTT blend fibers or filaments or PBT-PTT blend fibers or filaments.

Particularly advantageous yarns of the type described above with the blend components polybutylene terephthalate (PBT) and polytrimethylene terephthalate (PTT) are characterized in that the fibers or filaments after the first, fifth and tenth

Elongation cycle fiber test with 5% and / or 10% total elongation have residual strains ε _R that are less than 0.1%.

The features a), b) and c) described above and then the fibers or filaments on the basis of which the yarns are produced according to the invention are first to be explained in more detail below:

If characteristic a) is fulfilled, i.e. there is no twist, then this leads to the fact that, compared to the prior art according to US Pat. No. 4,475,330 which has been found to be relevant above, textile fabrics made therefrom have no creping effect and that there is no tendency to curl or crimp in the yarns and twists .

The same advantage arises when feature b) is fulfilled, i.e. a protective rotation with a metric rotation coefficient of 0.2 to 10 is set, the rotation coefficient α being defined in accordance with DIN 53832 α = (t / m •> ldtex) / 100, where t / m is the number of rotation per meter and dtex the Fineness of the fibers or filaments mean, "dtex" is determined in accordance with the standard specification DIN 53812, part 1.

A feature α) in the range from about 0.5 to 8, in particular from about 1 to 5, is particularly preferred for feature b) required for feature c), it is to be understood that a rotation coefficient α of up to 130 is selected here. The range from about 30 to 110, in particular from about 35 to 90, is preferred. In connection with fabrics, it is preferred that the weft threads have a twist e of 30 to 70 and the warp threads have a twist α of 80 to 130.

Particularly preferred yarns according to the invention are produced on the basis of the methods or filaments described by their production by melt spinning with subsequent preparation application. Melt spinning is carried out in the manner described later, the same also applies to the preparation order.

The invention also relates to the use of the specified polymer blend fibers in the form of undyed or dyed fibers or filaments for the production of the yarns according to the invention, the usual procedure being for textile fabrics, in particular carpets, knitted fabrics, fabrics, nonwovens or felts. Turned up

Yarns with a twist greater than 300 m ^"1 are excluded. The fibers or filaments used to manufacture the yarns according to the invention can be dyed with dispersion dyes without pressure and carrier-free at temperatures of about 70 ° C. of the dyeing liquor, high-temperature (HT) dyeings It should also be noted that the yarns according to the invention differ from those described in US Pat. No. 4,475,330, particularly in connection with those yarns which are based on the combination PET / PTT.

The invention will be explained in more detail below using examples, including 14 tables and 2 figures: Examples

1. Production of the Fibers from Polymer Blends by a Melt Spinning Process Mixing and Drying the Granules:

Granulate mixtures of PET with PTT and PBT with PTT were produced in the following weight ratios (data in% by weight):

PET / PTT-PBT / PTT

Speak mixture speak

100/0 100/0

90/10 90/10

70/30 70/30

50/50 50/50

30/70 30/70

10/90 10/90

0/100 0/100

Tab. 1: Composition of the granulate mixtures for blend fibers

The following granules were used: PET: Type 51, Hoechst, η _re ι 1.84; PBT: Type 1100 S, Nylstar, η _re ι = 2.13 PTT: pilot product, Degussa, ηrei = 2.21.

All relative solution viscosities given here result from measurements in the solvent system phenol / tetrachloroethane 1: 1 (m / m) with polymer concentrations of lg / 100 ml in Ubbelohde viscometers (size la, K ~ 0.05) at 20 ° C. The Hagenbach corrections were taken into account both for the solutions and for the solvent. The granulate mixtures were mixed in a 100 dm ³ tumble dryer from Henkhaus at rotational speeds of 6 revolutions / minute during the drying preceding the spinning process. The granulate mixtures were dried at 105 ° C. for 1 hour, then at 160 ° C. for 10 hours, at a final pressure of 0.08 mbar. The dryer was then cooled to room temperature within 12 hours. The pressure equalization took place with pure nitrogen. The water content of the dried polymers was <0.005%.

Melting spinning:

The polymer mixtures were spun at temperatures between 295 ° C. (pure PET) and 265 ° C. (pure PBT and PTT) using a Blaschke spinning extruder (0 30 mm, L / D = 25) through a 24-hole nozzle. To improve melt homogenization, the screw tip was equipped with a dynamic mixing part, the Maddock / Le Roy system and the adjoining cylinder area with two static mixing elements, the Sulzer system. The polymer melt was metered in the spinning head by means of a spinning pump and then filtered in front of the spinneret. The winding took place after preparation with traversing at a frequency-controlled winding speed of 3500 m / min.

An aqueous emulsion of 10% Dryfi RIL and 1.5% Ukanol R (from the company Schill and Seilacher, Böblingen) was used as the spin preparation. The spinning titers were between 94 and 105 dtex. This corresponds to a fineness of 3.9 to 4.4 dtex per single filament.

PET / PTT spinning temperature PBT / PTT spinning temperature

[% PTT] [° C] [% PTT] [° C]

0 295 0 265

10 295 10 265

30 280 30 265 50 275 50 267

70 272 70 270

90 270 90 270

100 265 100 265

Tab. 2: Spinning temperatures of the polymer mixtures made of PET and PTT as well as PBT and PTT

Draw: The staple fibers obtained in this way were drawn using a Zinser (Ebersbach / Fils) drawing system which has three heatable godets and two heating rails in between. The drawing factors were chosen so that the drawn fiber has about 25% elongation at break Stretching factors were between 1.45 (PET) and 1.32 (PTT) or 1.2, (PBT / PTT blends), the stretching speeds at V = 200 to 250 m / min. The stretching titers were between 65 and 70 dtex, what a delicacy of

Corresponds to 2.7-2.9 dtex per single filament.

Tab. 3: Parameters in the stretching process

2. Textile mechanical properties of the undrawn and drawn fibers and measurement of the residual strains ε _R on these fibers

These data were measured after the fibers had been adapted to the standard climate of 65% relative atmospheric humidity at 20 ° C in accordance with DIN 53802-20 / 65 using a tensile testing machine in accordance with DIN 51211 Part 1 from Textechno of the type Statimat M. The initial fineness of the fibers is determined by weighing 100 m of fiber each. For this purpose, the fibers are drawn off the spool using a L 232 winder from Zweigle. 200 mm / min is selected as the clamping length and 200 mm / min as the deformation speed. The jaws are made of Vulkolan and anodized aluminum; the air pressure for generating the clamping pressure is 7 bar. 30 measurements are carried out per sample and the mean value is formed.

The mechanical properties of the staple and hidden fibers are listed below:

Tab. 4: Staple fibers of the PET / PTT blends

Tab. 5: Staple fibers of the PBT / PTT blends

Tab. 6: Drawn fibers of the PET / PTT blends

Tab. 7: Drawn fibers of the PBT / PTT blends

The residual elongations of the fibers were measured on the Statimat M tensile testing machine from Textechno with the following parameters:

Clamping length: 250 mm

Test speed: 50 mm / min

Readjustment speed: 250 mm / min

Preload: 3 cN (0.025 cN / tex)

Jaws: Vulkolan

Number of cycles: 10

Waiting time after relieving: 5 minutes

Number of tests: 2, with averaging

FIG. 1 shows the schematic tensile force F-strain cycle according to DIN 53835 part 3, ie the schematic representation of a strain cycle with the strains shown: εo - total strain εu - elastic strain ε _R - residual strain The following residual strains were found for the PBT / PTT blended fibers:

Tab. 8: Residual strains εR of the PBT / PTT blend fibers after 5% and 10% total stretch εc after the 1st, 5th and 10th cycle.

In contrast to the following PET / PTT blend fibers, the residual strains εR for the 5% and 10% total elongation cycles of the PBT / PTT blend fibers prove to be independent of the composition of the blend. The results of the residual elongation determinations from the tensile stress strain for the PET / PTT blend fibers are contained in Tables 9 and 10:

Tab. 9: Residual strains εR of the PET / PTT blend fibers after 5% total elongation εo after the 1st, 5th and 10th cycle

Tab. 10: Residual elongations R of the PET / PTT blend fibers after 10% total elongation εc after the 1st, 5th and 10th cycle As can be seen from the measurement results, surprisingly, a very pronounced decrease in the residual elongation R occurs in the stretched PET / PTT blend fibers from as little as 10% by weight of PTT. This decrease in the residual elongation values R is far more pronounced than it corresponds to a decrease proportional to the percentage by weight of the PTT in the PET / PTT blended fibers. Figure 2 illustrates this fact graphically. The residual strains R of the PET / PTT blend fibers found after 5% total stretch after the ♦ 1st cycle, ■ 5th cycle, Δ 10th cycle (- line) and a course proportional to the composition (- - - lines) are shown. These exceptionally low residual strains are particularly advantageous in applications where good elasticity or repetition is important, such as in carpets, knitted fabrics and fabrics.

3. Coloring tests with the PET / PTT and PBT / PTT blend fibers

Substrates:

The use of fiber flake has the disadvantage that the fibers can knot and then can no longer be washed around uniformly by the dye liquor. The uneven dyeings obtained from this cannot be used to determine the dye content. The dyeing tests were therefore carried out using knitted fabrics made from drawn fibers. A circular knitting machine of the Elba type from the Lucas machine factory was used to manufacture the knitted fabrics.

So that the stretching titers and thus the fiber diameters of the fibers to be dyed are comparable, different spinning titers were chosen because of the different stretching factors. After knitting, the fibers were washed on a circular knitting machine to remove the preparation applied during knitting. Pretreatment:

The knitted fabrics were washed as follows to remove the spin finish:

Apparatus: Mathis LAB Jumbo Jet with washing drum temperature: 30 ° C

Duration: 60 min

Wash liquor: 1 g / 1 Kieralon EDB from Bayer AG. Fleet ratio: 1:10

To avoid shrinkage during dyeing and to improve the dimensional stability of the knitted fabrics, they were thermally fixed at 180 ° C. for one minute. The tensions in the fiber that arise during stretching are relaxed.

Dyes: Two disperse dyes were selected that differ significantly in their diffusion coefficient:

CI Disperse Blue 139 (mono azo dye resolin navy blue GLS from Bayer AG): D = 0.8 • 10 ^"10 cm ² s ^{" 1}

CI Disperse Red 60 (antrachinone dye Resolin Red FB from Bayer AG): D = 3.4 "10 ^ cn s ^{" 1}

For the quantitative determination of the dye absorption, the extinction coefficient of the pure dye must be known. The cleaning of the above-mentioned disperse dyes is carried out by E.M. Schnaith (dissertation 1979, Uni. Stuttgart) presented in detail.

The dyeing temperatures were varied between 70 and 130 ° C. The dyeing was always started at 35 ° C and the heating rate was chosen so that the dyeing temperature after 45 min. was achieved. After a dyeing time of 60 min. was with a cooling rate of 1 K / min. cooled to a bath temperature of 40 ° C. Staining conditions: Apparatus: Ahiba Polymat staining time: 60 min. Fleet ratio: 1:50

Liquor: 0.4 g / 1 dye (2% color) 0.75 g / 1 Avolan IS from Bayer AG 1-2 drops of 30% acetic acid (to adjust pH 5-6)

Reductive post-treatment:

The dyeings were reductively treated to remove the dye that had deposited on the fiber surface. The heating rate of the reduction liquor was 2

K / min. , the cooling rate 1 K / min.

Reduction conditions: Apparatus: Ahiba Polymat

Temperature: 70 ° C

Duration: 20 min.

Fleet ratio: 1:50

Liquor: 2 g / 1 sodium dithionite 4 ml / 1 32.5% by weight sodium hydroxide solution

0.75 g / 1 Levegal HTN from Bayer AG

Dye absorption:

To determine the dye absorption, the fibers dyed at different temperatures were extracted with chlorobenzene. The extracts were diluted to a defined volume and the extinctions of the solutions were determined with the aid of a UV-VIS spectrophotometer of the Lambda 7 type from Perkin Elmer in Lake Constance. From the extinction of the extraction solution at the characteristic wavelength. CI Disperse Blue 139 at 604 nm, CI Disperse Red 60 at 516 nm the dye content can be determined using the corresponding calibration line. The applied dyeing process with evaluation was developed by HJ.L. Traub described in detail (dissertation, University of Stuttgart, 1994).

The maximum determinable dye uptake is about 95% of the maximum possible dye uptake, since the fiber samples are reductively aftertreated before extraction. The dye adhering to the fiber surface is reductively destroyed and the maximum determinable dye content is thereby reduced.

Tab. 11: Dye absorption (Disperse Blue 139) of the PET / PTT mixtures depending on the dyeing temperature (maximum: 4.4 g / kg)

Table 12: Dye absorption (Disperse Blue 139) of the PBT / PTT mixtures depending on the dyeing temperature (maximum: 4.4 g / kg)

Tab. 13: Dye absorption (Disperse Red 60) of the PET / PTT mixtures depending on the dyeing temperature (maximum: 5.9 g / kg)

Tab. 14: Dye absorption (Disperse Red 60) of the PBT / PTT mixtures depending on the dyeing temperature (maximum: 5.9 g / kg) It is surprisingly clear from the dye uptake for the disperse dyes Disperse Blue 139 and Disperse Red 60 by the PET / PTT and PBT / PTT blend fibers that these blend fibers produce relatively higher pressureless and carrier-free dyeings at dyeing temperatures in the range from 70 to 100.degree Dye uptake can be achieved than with pure PBT and PTT fibers. The maximums of the dye uptake are in the mixing ranges of 30-70% and almost reach the high temperature dye uptake values.

HT dyeings between 100 and 130 ° C only lead to insignificantly higher dye uptake in the entire mixing range X 0% <X <100%. However, these can no longer be carried out in open systems without pressure.

The filament yarns obtained were drawn on the one hand on a drawing system from the Zinser company (Ebersbach / Fils), which has three heatable godets and two heating rails in between. No rotation is given here. On the other hand, the

Stretching was carried out on a stretching system from Dienes Apparatebau (Mühlheim / Ruhr), a protective rotation having a rotation coefficient α of approximately 1 being produced. The stretching factors were chosen so that there is an elongation at break of 25%.

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Claims

claims

1. Yarns made from polymer blend fibers or filaments, comprising the blend components 1) polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) and 2) polytrimethylene terephthalate (PTT) in a mixing ratio of 1): 2) of about 5:95 to 95: 5, in particular about 10:90 to 90: 10, characterized in that the fibers or filaments of the yarns have an elongation at break of 15 to 35% after one or more stretching processes and that, after stretch cycle fiber tests with 5% total elongation, have smaller remaining elongations ε _R , than that for the first stretch cycle by the equation ε _R [%] - 0.61 - (0.59 / 100) • X, for the fifth stretch cycle by the equation ε _R [%] = 0.69 - (0.67 / 100) • X and for the tenth stretch cycle by the equation ε _R [%] = 0.67 - (0.65 / 100) • X the remaining residual strain ε _R , where in these equations the variable X is the percentage by weight of the PTT from about 5 to 95% in the PET-PTT blend Fibers or filaments or PBT-PTT blend fibers or filaments means that the yarns a) no twist, b) a protective twist with a metric twist factor α of 0.2 to 10 or c) with standard twist a twist factor α to to 130, for which the twist factor α is the standard DIN 53832 described above and α = (t / m »NI dtex) / 100, where t / m is the number of twists per meter and dtex is the fineness of the fibers or filaments .

2. Yarns according to claim 1, characterized in that the fibers or filaments after elongation cycle fiber tests, in a change from 5% to 10% total elongation, have smaller remaining elongations ε _R than those for the first elongation cycle by the equation ε _R [ %] = 3.36 - (3.34 / 100) • X, for the fifth stretch cycle by the equation ε _R [%] = 4, 16 - (4, 14/100) • X and for the tenth stretch cycle by the Equation ε _R [%] = 4.42 - (4.40 / 100) • X calculated residual elongation ε _R , in these equations the variable X means the percentage by weight of the PTT of about 60 to 95% in the PET-PTT blend fibers or filaments or PBT-PTT blend fibers or filaments.

3. Yarns according to claim 1 or 2 with the mixture components polybutylene terephthalate (PBT) and polytrimethylene terephthalate (PTT), characterized in that the fibers or filaments after the first, fifth and tenth stretch cycle fiber test with 5% and / or 10% total elongation have remaining residual strains ε _R that are less than 0.1%.

4. Yarn according to at least one of the preceding claims, characterized in that yarns with the feature b) have a twist coefficient in the range from about 0.5 to 8, in particular from 1 to 5.

5. Yarn according to at least one of the preceding claims, characterized in that yarns with the feature c) have a twist coefficient α in the range from about 30 to 110, in particular from about 35 to 90.

6. Yarn according to at least one of the preceding claims, characterized in that the fibers or filaments by melt spinning with subsequent

Preparation order have been produced.

7. Use of the yarns according to at least one of claims 1 to 6 as undyed or dyed yarns for textile fabrics, in particular carpets, knitted fabrics, woven fabrics, nonwovens or felts.

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