Method for the spinning and winding of polyester
filaments using a spinning additive, polyester
filaments obtained by the spinning method, draw
texturing of the polyester filaments and bulked
polyester filaments obtained by draw texturing
The present invention relates to processes for spinning and winding POY polyester filaments not less than 90% by weight, based on the total weight of the polyester filament, polyb utylene terephthalate (PBT) and/or polytrimethylene terephthalate (PTMT), preferably PTMT, b y using spinning additives and also to the POY polyester filaments ob tainab le b y the process. The present invention further also relates to processes for draw texturing the spun and wound polyester filaments and also to the b ulky polyester filaments ob tainab le thereby.
The production of continuous polyester filaments and especially of polyethylene terephthalate (PET) filaments in a two-step process is already known. In this process, the first step comprises spinning and winding flat POY filaments which are fully drawn and heatset or draw-textured to bulky filaments in a second step.
An overview of this field is given b y the b ook Synthetische Fasern by F. Fourn6 (1995), published by Hanser, Munich. However, only the production of PET fibers is described and no unified spinning technology is presented, only an overview describ ing the most diverse features.
Fib er production from various spinnab le polymers, including polypropylene, polyamides, polyester, etc., forms part of the subject matter of DE-A 38 19 913. However, only the production of PET fibers is described

in the examples, as is discernible from the temperature at which the polymer is processed.
The problem with producing continuous polytrimethylene terephthalate (PTMT) or polyb utylene terephthalate (PBT) filaments is that POY filaments, not only directly after spinning and in winding b ut also for several hours after winding, in the course of storage at room temperature, exhibit a considerable tendency to shrink, which leads to yarn shortening. The package is compressed as a result, so that, in the extreme case, the package will shrink solid onto the winding mandrel and can no longer be removed. Furthermore, the package will develop a so-called saddle with hard edges and a waisted center portion. As a result, textile data of the filaments, for example the Uster value, become less uniform and prob lems develop when unwinding the packages. Such problems do not arise in the processing of PET fibers.
It is further ob served that, in contradistinction to PET filaments, POY PBT or PTMT filaments age fast in the course of storage. Structure hardening occurs and causes the b oiloff shrinkage to decrease to such a large extent that aftercrystallization can be detected. Such PBT or PTMT filaments are only partially suitable for further processing in that they lead to defects in draw texturing and to a significant reduction in the breaking strength of the textured yarn.
These differences between PET on the one hand and PBT and PTMT on the other are attrib utab le to structural and property differences, as reported for example in Chemical Fib ers Int., p. 53, vol. 50 (2000} and discussed at the 39th International Manmade Fib re Congress at Dornb irn from September 13 to 15. It is accordingly b elieved that different chain formations

are responsible for the property differences.
The first approaches to solving these prob lems are describ ed in WO 99/27168 and EP 0,731,196 Bl. WO 99/27168 discloses a polyester fiber which is at least 90% by weight polytrimethylene terephthalate and has a b oiloff shrinkage b etween 5% and 16% and a b reaking extension of 20% to 60%. The polyester fiber described in WO 99/27168 is produced by spinning and drawing. The maximum spinning takeoff speed reported is 2 100 m/min. The process is uneconomical because of the low spinning speed. In addition, the polyester fibers obtained are, as the reported parameters document, highly crystalline and hence only partially suitab le for draw-texturing processes.
EP 0,731,196 Bl describ es a process for spinning, drawing and winding a synthetic yarn by subjecting the yarn to a heat treatment after drawing and b efore winding to reduce its tendency to shrink. Synthetic fib ers which can b e used include polytrimethylene terephthalate fib ers. In EP 0,731,196 Bl, the heat treatment is effected b y the synthetic yarn b eing guided in close vicinity to b ut essentially contactlessly along an elongate heating surface. The application of a heat treatment adds to the cost of the process and, what is more, provides synthetic yarns of high crystallinity which are only partially suitab le for draw-texturing processes.
The article b y Dr. H.S. Brown and H.H. Chuah; "Texturing of textile filament yarns b ased on polytrimethylene terephthalate" Chemical Fib ers International, Volume 47, Feb r. 1997, p. 72-74 describ es the draw texturing of POY polytrimethylene terephthalate filaments at texturing speeds of 450 m/min and 850 m/min. According to this disclosure, the

lower texturing speed of -950 m/min is more suitable for polytrimethylene terephthalate filaments, since fibers having better material properties are obtained in this case. The b reaking strength of the polytrimethyiene terephthalate fib ers is reported as 26.5 cN/tex
(texturing speed 450 m/min) and 29.15 cN/tex {texturing speed 850 m/min) and the breaking extension as 38.0%
(texturing speed 50 m/min) and 33.5% (texturing speed 850 m/min).
WO 01/04393 describes PrMT filaments having a boiloff shrinkage in the range from 3 to 40%. However, this value is determined immediately after the filaments have been formed. This value decreases to below 20% in the course of A weeks of storage under standard conditions, as documented by the accompanying figure 1.
Figure 1 describes the change in the boiloff shrinkage for three PTMT POY bobbins as a function of the storage time under standard conditions. The three b ob b ins investigated had different initial values. Bobbins #16 and 17, having a high initial value of > 40%, have a b oiloff shrinkage after 4 weeks of ab ove 30% and preferab ly of ab ove 40%. However, when the initial boiloff shrinkage value is less than 40%, it is evident from bobbin 18 that the boiloff shrinkage value will drop to below the critical value of 30% after a storage time of 4 weeks.
The boiloff shrinkage is a measure of the ———— processibiiity and the crystallinity of the fibers. The fib ers describ ed in WO 01/04393 comprise plastics having a comparatively high crystallinity, which are significantly more difficult to process and can only be processed at a lower draw ratio and/or at a lower texturing speed.

It is an ob ject of the present invention to provide a process for spinning and winding POY polyester filaments not less than 90% by weight, based on the total weight of the filaments, PBT and/or PTMT whereby POY polyester filaments are simple to produce and wind up. More particularly, the POY polyester filaments shall have b reaking extension values in the range of 90%-165%, a high utiifornvity with regard to filament parameters and also a low crystallinity.
It is a further ob ject of the present invention to provide an economical industrial process for spinning and winding POY polyester filaments. The process of the invention shall permit very high spinning takeoff
speeds, preferably above 2200 m/rain, and high yarn weights on the package of more than 4 kg.
It is yet a further object of the present invention to improve the storability of the POY polyester filaments obtainable by the process of the invention. They shall
be storable for a prolonged period, for example 4
weeks. Ideally, the package shall not compact in the
course of storage, especially shall not shrink solid on
the winding mandrel and form a saddle having hard edges
and waisted center portion, so that there shall be no
problems unwinding from the package.
According to the invention, the POY polyester filaments shall b e simple to further process in a drawing or draw-texturing operation, especially at high texturing
speeds, preferably above 450 m/min. The filaments ob tainab le b y draw texturing shall have excellent material properties, for example a high b reaking strength of more than 26 cN/tex and a high b reaking extension of more than 30% for HE filaments or more than 36% for SET filaments.

These and other objects not explicitly mentioned but readily derivable or apparent from the related matters discussed herein at the beginning are achieved b y a process for spinning and winding that comprises all the features of the present invention. Advantageous modifications of the process according to the invention are also protected. The POY polyester filament obtainable by the spinning process is described in an independent product claim. The draw texturing of the POY polyester filaments and bulky filaments obtainable by the draw texturing are also claimed in subsidiary claims.
The present invention accordingly provides a process for producing and winding POY filaments not less than 90% by weight, based on the total weight of the polyester filament, polybutylene terephthalate (PBT) and/or polytrimethylene terephthalate (PTMT), preferably PTMT, characterized in that it comprises
a) setting the spinline extension ratio in the range from 70 to 500.
b) passing the filaments directly upon exit from the spinneret through a quench delay zone 3D mm to 200 mm in length,
c) quenching the filaments to below the solidification temperature,
d) converging the filaments at a distance between 500 mm and 2 500 mm from the underface of the spinneret,
e) setting the yam tension above and between the takeoff godets between 0.05 cN/dtex to 0.20 cN/dtex,
f) taking the yam up at a yam tension between 0.025 cN/dtex to 0.15 cN/dtex,
g) setting the takeup spef hfi/p"" "> '">n m/miri and 6

000 m/mln h) and using a polyester which contains 0.05% b y
weight to 2.5% by weight, based on the total weight of the filament, of additive polymer extensibility enhancer in admixture.
This unforeseeable process provides POY polyester filaments which maintain their excellent material properties even after 4 weeks of storage under standard conditions. No significant worsening in the uniformity values of the yarn due to aging and no shrinkage of the spun fiber on the bobbin are observed.
At the same time, the process of the invention has a number of further advantages. These include:
=:> The process of the invention is simple and
economical to practice on a large industrial scale. More particularly, the process permits spinning and winding at high takeoff speeds of at least 2 200 m/min and the production of packages holding high yarn weights of more than 4 kg.
=> The use of spinning additives makes it possible to achieve takeoff speeds of up to 6 000 m/min. The equipment can be operated particularly economically as a result.
=> The POY polyester filaments ob tainab le b y the process can thus be further processed in a drawing or draw-texturing operation simply, economically and on a large industrial scale. In the operation, the texturing can be carried out at speeds above 'SO m/min,
Owing to the high uniformity of the POY polyester filaments obtainable by the process, it is simple

to achieve good package build to ensure uniform and sub stantially defect-free dyeing and further processing of the POY polyester filament.
=> The filaments obtainable by the draw texturing have a high brea}cing strength of more than 26 cN/tex and a high breaking extension of more than 30% for HE filaments and more than 36% for SET filaments.
The present invention provides a process for producing and for winding POY polyester filaments not less than 90% by weight polybutylene terephthalate (PBT) and/or polytrimethylene terephthalate (PTMT), b ased on the
total weight of the filament. Polybutylene terephthalate (PBT) and/or polytrimethylene terephthalate (PTMT) are known to one skilled in the art, Polybutylene terephthalate (PBT) is obtainable by polycondensation of terephthalic acid with equimolar
amounts of 1,4-butanediol and polytrimethylene
terephthalate is ob tainab le b y polycondensation of
terephthalic acid with equimolar amounts of
1,3-propanediol. Mixtures of the two polyesters are
also conceivab le. According to the invention, PTMT is
preferred.
The polyesters may be homopolymers or copolymers.
Useful copolymers include especially copolymers which,
as well as PTMT and/or PBT repeat units, contain up to
15 mol%, b ased on all the repeat units of the
polyesters, of repeat units of customary comonoraers,
for example ethylene glycol, diethylene glycol,
triethylene glycol, 1,4-cyclohexanedimethanol,
polyethylene glycol, isophthalic acid and/or adipic
acid. For the purposes of the present invention,
however, polyester homopolymers are preferred.
The polyesters of the invention may include customary

amounts of further additives as admixtures, such as catalysts, stab ilizers, antistats, antioxidants, flame retardants, dyes, dye uptake modifiers, light stab ilizers, organic phosphites, optical b righteners and delusterants. Preferably, the polyesters include 0 to 5% by weight of additives, based on the total weight of the filament.
The polyesters may further include a small fraction, preferably up to 0.5% by weight, based on the total weight of the filament, of b rancher components. Preferred b rancher components according to the invention include polyfunctional acids, such as trimellitic acid, or pyromellitic acid, or tri- to hexavalent alcohols, such as trimethylolpropane, pentaerythritol, dipentaerythritol, glycerol or corresponding hydroxyacids.
In the context of the present invention, the PBT and/or PTMT are admixed with 0.05% b y weight to 2.5% by weight, based on the total weight of the filament, of additive polymers as extensib ility enhancers. Particularly useful additive polymers for the purposes of the invention include the hereinb elow specified polymers and/or copolymers:


B = styrene or C]__3-aikyl-substituted styrenes,
the copolymer consisting of 60 to 98% by weight of A and 2 to 40% by weight of B, preferably of 83 to 98% by weight of A and 2 to 17% by weight of B, and more preferably of 90 to 98% by weight of A and 2 to 10% by weight of B (sum total = 100% by weight).
A copolymer containing the following monomer units:

the copolymer consisting of 15 to 95% by weight of C and 2 to 80% by weight of D, preferably of 50 to 90% by weight of C and 10 to 50% by weight of D and more preferably of 70 to 85% of C and 15 to 30% by weight of D, the sum total of C and D being

100% by weight.
i. A copolymer containing the following monomer units:
E = acrylic acid, methacrylic acid or CHo =
CR-COOR' , where R is an H atom or a CH3 gr'oup and R' is a C]_-15-alkyl radical or a C5_]_2 -cycloalkyl radical or a Cg_]_4-aryl radical,

H = one or more ethylenically unsaturated
monomers which are copolymerizab le with E and/or with F and/or G and are selected from

the group consisting of a-methylstyrene, vinyl acetate, acrylic esters, methacrylic esters other than E, vinyl chloride, vinylidene chloride, halogen-sub stituted styrenes, vinyl ethers, isopropenyl ethers and dienes,
the copolymer consisting of 30 to 99% by weight of E, 0 to 50% by weight of F, >0 to 50% by weight of G and 0 to 50% by weight of H, preferably of 45 to 97% by weight of E, 0 to 30% by weight of F, 3 to 40% by weight of G and 0 to 30% by weight of H and more preferably of 60 to 94% by weight of E, 0 to 20% by weight of F, 6 to 30% by weight of G and 0 to 20% by weight of H, the sum total of E, F, G and H being 100% by weight.

1 0
where R-'- and R are substituents consisting of the
optional atoms C, H, 0, S, P and halogen atoms and
the sum total of the molecular weights of R-*- and R
9
is at least 40. Exemplary monomer units include
acrylic acid, methacrylic acid and CH2 = CR~COOR', where R is an H atom or a CH3 group and R' is a C
2__;L5-all15 n/m, which are characterized b y high uniformity in that the coefficient of variation is not more than 70% and the maximum nodeless gap is 50 cm. In actual service, systems of the LD type from Temco/Germany, the double system from Slack & Parr/USA or Polyjet from Heb erlein have b een found to b e particularly useful.
The circumferential speed of the first godet unit is referred to as takeoff speed. Further godet systems can b e employed b efore the yarn is wound up in the wind assembly to form packages (bobbins) on formers.
Stable, defect-free packages are a basic prerequisite for defect-free winding of the yarn and for an ideally defect-free further processing. Therefore, in the context of the present invention, the takeup tension employed is in the range of 0.025 cN/dtex - 0.15 cN/dtex and preferably in the range of 0.03 cN/dtex -0.08 cN/dtex.
An important parameter of the process according to the invention is the yarn tension setting above and between the takeoff godets. As will be known, this tension is made up essentially of Hamana's actual orientation tension, the frictional tension on the yarn guides and the oiler and the yarn-air frictional tension. For the purposes of the present invention, the yarn tension above and between the takeoff godets is in the range from 0.05 cN/dtex to 0.20 cN/dtex and preferably in the

range between 0.08 cN/dtex and 0.15 cN/dtex.
An excessively low tension below 0.05 cN/dtex no longer provides the desired degree of partial orientation. When the tension exceeds 0.20 cN/dtex, this tension will induce a memory effect in the course of winding and storing the bobbins that leads to a deterioration in yarn parameters.
The tension is controlled according to the invention by the distance of the oiler from the jet spinneret, the frictional surfaces and the length of the gap b etween oiler and takeoff godet. This length is advantageously not more than 6.0 ra and preferably less than 2.0 m, the spinning system and the takeoff machine being disposed in such a way by parallel construction as to ensure a straight yarn path.
The geometric parameters also describe the conditioning time of the yarn between converging point and takeup. The fast relaxation during the period has an effect on the quality of package build. The conditioning time so defined is preferably chosen to be between 50 and 200 ms.
The takeup speed of the POY is between 2 200 m/min and 6 000 m/min according to the invention. It is preferable to choose a speed between 2 500 m/min and 6 000 m/min. It is particularly preferab le for the polymer blends to be wound up at speeds in the range from 3 500 m/min to 6 000 m/min.
Advantageously, the process according to the invention is carried out by adjusting the environment of the yarn
package to b e at a temperature <45°C, especially between 12 and 35°C, and a relative humidity of 40 -85%. It is further advantageous to store the POY

packages at 12 to 35°C and a relative humidity of 40-85% for at least 4 hours prior to further processing.
After 4 weeks of storage under standard conditions, the filament according to the invention has
a) a b reaking extension b etween 90% and 165%, preferably between 90 and 135%,
b) a boiloff shrinkage of at least 30%, preferably
>40%,
c) a normal Uster b elow 1.1%, preferab ly b slow 0.9%,
d) a birefringence between 0.030 and 0.058,
e) a density of less than 1.35 g/cmf preferably less than 1.33 g/cm-,
f) a breaking load coefficient of variation <4.5%, preferably <2,5% and
g) a breaking extension coefficient of variation < 4.5%, preferably £2.5%
The term "standard conditions" is known to one skilled in the art and defined via the DIN 53802 standard. Under "standard conditions" as per DIN 53802, the temperature is 20±2°C and the relative humidity 65±2%.
It is additionally particularly advantageous for the purposes of the present invention for the b oiloff shrinkage to b e b etween 50 and 65% when measured directly after windup and to b e at least 30% and
preferably >40% after 4 weeks of storage under standard conditions. It has been determined that, surprisingly, POY bobbins produced in this way have excellent further processing properties.
Methods for determining the indicated material parameters are well known to those skilled in the art.

They are discernib le from the technical literature. Although most of the parameters can b e determined in various ways, the following methods for determining the filament parameters will prove particularly advantageous for the purposes of the present Invention:
The intrinsic viscosity is measured at 25''C in an
Ub b elohde capillary viscometer and calculated b y the
familiar formula. The solvent used is a 3:2 w/w mixture
of phenol and 1,2-dichlorobenzene. The concentration of
the solution is 0.5 g of polyester per 100 ml of
solution.
The melting point, the crystallization temperature and the glass transition temperature are each determined using a DSC calorimeter from Mettler. The sample is initially heated to 280°C to melt it and then quenched. The DSC measurement is done in the range from 20°C to 280''C at a heating rate of 10 K/min. The reported temperatures are determined by the processor.
Filament density is determined in a density gradient column at a temperature of 23±0.1°C. The reagent used is n-heptane (C7HX6) and tetrachloromethane (CCI4}. The result of the density measurement can b e used to calculate the crystallinity on the basis of the density of the amorphous polyester D and the density of the
crystalline polyester D]. The calculation is described in the literature and for PTMT for example the corresponding values are Dg = 1.295 g/cm and Dj =
1.429 g/cm3.
Linear density is determined in a known manner using a precision reel and weighing means. The pretension used is advantageously 0.05 cN/dtex for POY and 0.2 cN/dtex for DTY.

Breaking strength and breaking extension are determined on a Statimat apparatus under the following conditions: the clamped length is 200 mm for POY and 500 mm for DTY, the rate of extension is 2 000 mm/min for POY and 1 500 mm/min for DTY and the pretension is 0.05 cN/dtex for POY and 0.2 cN/dtex for DTY. The maximum breaking load values are divided b y the linear density to determine the breaking strength, and breaking extension is determined at maximum load.
Boiloff shrinkage is determined b y treating filament skeins in water at 95±1°C for 10+1 min in a tensionless state. The skeins are prepared b y reeling at a pretension of 0.05 cN/dtex for POY and 0.2 cN/dtex for DTY; the length measurement of the skeins b ef ore and after the thermal treatment is carried out at 0.2 cN/dtex. The difference in length is used to calculate the boiloff shrinkage in a known manner.
Birefringence is determined by the method described in DE 19,519,898, the disclosure of which is explicitly incorporated herein by reference.
The crimp parameters of the textured filaments are measured in accordance with DIN 53840 Part 1 using a Texturmat apparatus from Stein/Germany at a development temperature of 120°C.
The normal Uster values are determined using a 4-CX
Uster tester and are reported as Uster % values. The
testing speed is 100 m/min and the testing time 2.5
min.
The POY according to the invention is simple to further process, especially draw texture. In the present invention, draw texturing is preferably carried out at a texturing speed of at least 500 m/min and particularly preferab ly at a texturing speed of at

least 700 m/min. The draw ratio is preferably at least 1.35:1 and especially at least 1.40:1. It will b e particularly advantageous to draw texture on a high temperature heater type machine, for example an AFK machine from Barmag.
The bulky filaments produced in this way exhibit a low numb er of defects and on dyeing at the b oil with a disperse dye without carrier an excellent depth of shade and uniformity of color.
Bulky SET filaments produced according to the invention preferab ly have a b reaking strength of more than 26 cN/tex and a breaking extension of more than 36%. In the case of bulky HE filaments, which are obtainable without thermal treatment in a second heater, the breaking strength is preferably more than 26 cN/tex and the breaking extension more than 30%.
The b ulk and elasticity b ehavior of the filaments according to the invention is excellent.
Illustrative embodiments of the invention will now be more particularly described without the invention being limited to these examples.
Examples 1 to 3

Spinning and winding
PTMT chips having an intrinsic viscosity of 0.93 dl/g, a melt viscosity of 325 Pa s (measured at 2.4 Hz and 255''C), a melting point of 227°C, a crystallization temperature of 72°C and a glass transition temperature of 45°C were tumble dried at 130°C to a water content of 11 ppm.
The chips were melted in a 3E4 extruder from Barmag, so that the temperature of the melt was 255''C. This melt had added to it various amounts of Plexiglas 7N polymethyl methacrylate from Rohm Gmb H/Germany as an extensibility enhancer which had beforehand been dried to a residual moisture content of less than 0.1%.
For this purpose, the additive polymer was melted in a melting extruder, fed using a gear wheel metering pump to the feed means and fed from there through an injection nozzle in the flow direction into the polyester component. The two melts were homogenized and finely dispersed in an SMX static mixer from Sulzer having 15 elements and an internal diameter of 15 mm.
The melt viscosity of the Plexiglas 7N was 810 Pa s (2.4 Hz, 255°C), as a result of which the ratio of additive and polyester melt viscosities was 2.5:1.
The transported amount of melt was 63 g/min coupled with a residence time of 6 min, and the amount metered from the spinning pump to the spinneret pack was adjusted so that the POY linear density was about 102 dtex. Various takeup speed settings were used. One element of an HD-CSE type static mixer from Fluitec having an internal diameter of 10 mm had been installed below the spinning pump, but above the point of entry into the spinneret pack. The secondary heating systems fot the product line and the spin b lock, which

contained the pump and the spinneret pack, had been set to 255°C. The spinneret pack contained 350-500 pm steel sand 30 mm in height and also a 20 \im nonwoven filter and a 40 pm woven filter as filter media. The melt was extruded through an 80 mm diameter spinneret plate containing 34 holes 0,25 ram in diameter and 1.0 mm in length. The die pressure was about 120-140 bar.
The quench delay zone was 100 mm in length, made up of 30 ram in heated walling and 70 mm in insulation and unheated frame. The molten filaments were quenched with air flowing horizontally against the spinline over a length of 1500 mm. The quenching air had a flow rate of 0.35 m/sec, a temperature of 18°C and a relative humidity of 80%. The filaments became solid at about 800 mm below the spinneret.
A yarn oiler positioned at a distance of 1 050 mm from the spinneret was used to apply spin finish to the ends before converging. The oiler had a TriboFil surface and an inlet opening 1 mm in diameter. The amount of spin finish applied was 0.4 0%, based on fiber weight.
The converged spinline was then fed to the winding machine. The distance between the oiler and the first takeoff godet was 3.2 m. The conditioning time was between 105 and 140 ms. A pair of godets was S-wrapped by the yarn. Situated between the godets was a Temco entangling jet, which was operated using an air pressure of 1.5 bar. In line with the speed setting, the takeup speed of the Barmag SW6 winder was set in such a way that the takeup yarn tension was 5 cN. The room conditions were adjusted to 24°C and 60% relative humidity so that a temperature of about 34''C ensued in the environment of the yarn package.
A significant increase in productivity was obtained for

all amounts of additive added. The 10 kg b ob b ins produced were readily removab le from the winding mandrel. The POY yarns obtained were notable for good time constancy of the yarn properties over a storage period of 4 weeks under standard conditions as defined in DIN 53802. The b oiloff shrinkage directly after spinning and winding was found to be in the range of 51-54%. The texturability and the uniformity of dyeing achieved were found to be excellent. The draw ratio to be used was surprisingly high for the POY speeds used.
The other parameters and characteristic data are summarized in tables 1 to 4.



1; measured after 4 weeks of storage under normal conditions

Draw texturing
The PTMT filament bobbins were stored for 4 weeks under standard conditions as defined in DIN 53802 and then presented to a Barmag FK6-S-900 draw texturing machine. The experimental parameters for draw texturing to produce SET filaments are summarized in table 3 and the material properties of the resulting b ulky SET filaments in table 4.
Texturing defects were determined using Barmag's



The co-pending application 157/CHENP/2003 refers to a process for spinning and winding POY polyester filaments not less than 90% by weight, based on the total weight of the polyester filament, polybutylene terephtalate (PBT) and/or polytrimethyle terephtalate (PTMT), preferably PTMT, without using spinning additives and also to POY polyester filaments obtaintable by the process. Further, it also relates to process for draw-texturing the spun and wound polyester bulky polyester filaments obtainable thereby.

We claim:
1. A process for producing and winding POY polyester filaments not less than 90% by weight, based on the total weight of the polyester filament, polybutylene terephthalate (PBT) and preferably polytrimethylene terephthalate (PTMT), preferably PTMT, characterized in that it comprises
a) setting the spinline extension ratio in the range from 70 to 500,
b) passing the filaments directly upon exit from the spinneret through a quench delay zone 30 mm to 200 mm in length,
c) quenching the filaments to below the solidification temperature,
d) converging the filaments at a distance between 500 mm and 2 500 mm from the underface of the spinneret
e) setting the yam tension above and between the takeoff godets between. 0.05 cN/dtex to 0.20 cN/dtex,
f) taking the yam up at a yam tension between 0.025 cN/dtex to 0.15 cN/dtex,
g) setting the takeup speed between 2 200 m/min and 6000 m/min.
h) and employing a polyester which contains 0.05% by weight to 2.5% by weight, based on the total weight of the filament, of additive polymer extensibility enhancer in admixture.
2. The process as claimed in claim 1, wherein that PBT and preferably PTMT having a limitmg viscosity number in the range from 0.7 dl/g to 0.95 dl/g are used.

3. The process as claimed in claim 1 and/or 2, wherein the taking up is effected by setting a temperature < 45°C in the ambience of the yam package,
4. The process as claimed in at least one of the preceding claims, wherein the POY bobbins are stored at 12-35''C and 40-85% relative humidity for at least 4 hours prior to further processing.
5. The process as claimed in at least one of the preceding claims, wherein the take-up speed is set between 2500m/min and 6000 m/min.
6. POY polyester filaments obtainable by a process as claimed in at least one of the preceding claims, wherein it has

a) a breaking extension between 90% and 165%,
b) a boiloff shrinkage of at least 30%.
c) a normal Uster below 1.1%,
d) a birefringence between 0.030 and 0.058.
e) a density of less than 1.35 g/cm preferably less than 1.33 g/cm
f) a breaking load coefficient of variation 54.5% and
g) a breaking extension coefficient of variation