KR20030043790A - Method for the spinning and winding of polyester filaments, polyester filaments obtained by the spinning method, draw texturing of the polyester filaments and bulked polyester filaments obtained by draw texturing - Google Patents

Abstract

Production of preoriented and melt spun polyester filaments comprising 90 wt.% of polybutylene terephthalate (PBT) of the total polyester filament weight and/or polytrimethylene terephthalate (PTMT) involves setting the spin draft, cooling directly and bundling together at a gap of 500-2500 mm. Production and winding of preoriented and melt spun polyester filaments comprising at least 90 wt.% of polybutylene terephthalate (PBT) of the total polyester filament weight and/or polytrimethylene terephthalate (PTMT) and is preferably wholly of PTMT. The spin draft is set at 70-500. The filaments are cooled directly on leaving the spinneret for a length of 30-200 mm, to a temperature below the setting point, and bundled together at a gap of 500-2500 mm from the under side of the spinneret. The filament tension before and between the godet rollers is 0.05-0.20 cN/dtex. The filament winding speed is 2200-6000 m/min. The polyester contains a polymer additive to increase its stretch, mixed in at a rate of 0.05-2.5 wt.% of the total filament weight. Independent claims are included for: (1) preoriented polyester filaments which, after four weeks of storage, have a stretch to break of 90-165%, a boiling shrinkage of at least 30%, a normal uster of =1.1%, a double refraction of 0.030-0.058, a density of =1.35 g/cm 3> and preferably =1.33 g/cm 3>, a variation coefficient of the shearing load and stretch to break of =4.5%; and (2) a bulked polyester filament, where the POY yarns are passed through a draw texturizing unit at a speed of at least 500 m/min. with a drafting ratio of at least 1:1.35 to give a bulked filament yarn with a shear strength of >=26 cN/tex and a stretch to break of >=30% or >=36%.

Description

FIELD OF THE SPINNING AND WINDING OF POLYESTER FILAMENTS, POLYESTER FILAMENTS OBTAINED BY THE SPINNING METHOD, DRAW TEXTURING OF THE POLYESTER FILAMENTS AND BULKED POLYESTER FILAMENTS OBTAINED BY DRAW TEXTURING}

The production of continuous polyester filaments, in particular polyethylene terephthalate (PET) filaments, by a two step process is already known. In this process, the first step involves spinning and winding of the fully drawn flat POY filament and in the second step, it is heat-fixed or stretch-textured to make bulky filaments.

An overview of this area is given by the book Synthetische Fasern (1995) by F. Fourne, published by Hanser, Munich. However, only the products of PET fibers are described and no uniform spinning technique emerges, only the outline describes the various features.

Fiber products of various spinnable polymers, including polypropylene, polyamide, polyester, and the like, form part of the subject matter of DE-A 38 19 913. However, as can be seen at the temperature at which the polymer is processed, only products of PET fibers are described in the examples.

A problem with the production of continuous polytrimethylene terephthalate (PTMT) or polybutylene terephthalate (PBT) filaments is that the POY filament is stored at room temperature immediately after winding and after several hours after winding, as well as It also tends to shrink in the middle, which causes shortening of the yarn. As a result, the package will be compressed, and in extreme cases the package will shrink and harden on the winding mandrel and not loosen therefrom. Moreover, the package will develop a form with a hard edge called a saddle and a concave central portion. As a result, the textile data of the filament, for example the Uster value, becomes less uniform and causes problems when unpacking. The only solution is to limit the weight of the package to less than 4 kg. Such a problem does not arise in the processing of PET fibers.

It is also observed that unlike PET filaments, Partially Oriented Yarn (POY) PBT or PTMT filaments rapidly age during storage. Hardening of the structure occurs and this causes the boiloff shrinkage to decrease so much that aftercrystallization is detected. Such PBT or PTMT filaments are only partially suitable for further processing in that they cause defects in stretch texturing and a significant reduction in the cut strength of the textured yarn. The result is a decrease in texturing speed or a decrease in draw ratio.

The difference between PET on one hand and PBT and PTMT on the other side is reported in, for example, the chemical fiber Int., P. As discussed at the meeting, it contributes to differences in structure and properties. Therefore, the difference in properties is believed to be due to different chain formation.

The first approach to solve this problem is described in WO 99/27168 and EP 0,731,196 B1. WO 99/27168 discloses polyester fibers having at least 90% by weight of polytrimethylene terephthalate and having an evaporation shrinkage between 5% and 16% and a cut elongation of 20% to 60%. Polyester fibers disclosed in WO 99/27168 are produced by spinning and drawing. The maximum spin takeoff speed reported is 2100 m / min. This process is uneconomical because of the low spinning speed. Moreover, the polyester fibers obtained are very crystalline, as reported in the parameters document, and are only partially suitable for the draw-texturing process.

EP 0,731,196 B1 describes processes for spinning, stretching and winding synthetic yarns which reduce their tendency to shrink by heat treating the yarns after stretching and before winding. Synthetic fibers that can be used include polytrimethylene terephthalate fibers. In EP 0,731,196 B1 the heat treatment is carried out by the synthetic yarn being guided very closely along the extended heating side but never in contact with the heating side. The application of heat treatment increases the cost of the process and furthermore provides the synthetic yarn with high crystallinity which is only partially suitable for the draw-texturing process.

H.S., International Chemical Fibers, Vol. 47, pp. 72-74. Dr. Brown and H.H. Chuah's thesis; "Texturing of woven filament yarns based on polytrimethylene terephthalate" describes the stretching texturing of POY polytrimethylene terephthalate filaments at texturing speeds of 450 m / min and 850 m / min. According to this disclosure, a low texturing rate of 450 m / min is more suitable for polytrimethylene terephthalate filaments because fibers with better physical properties are obtained. The cut strength of the polytrimethylene terephthalate fiber is 26.5 cN / tex (texturing speed 450 m / min), 29.15 cN / tex (texturing speed 850 m / min), and the cut elongation of the fiber is 38.0% (texturing speed 450 m / min) and It is reported as 33.5% (texturing speed 850 m / min).

WO 01/04393 describes PTMT filaments with evaporative shrinkage in the range of 3-40%. However, this value is determined as soon as the filament is formed. This value drops below 20% during storage for 4 weeks under standard conditions as shown by the accompanying figure 1.

The invention relates to the spinning of POY polyester filaments comprising at least 90% by weight of polybutylene terephthalate (PBT) and / or polytrimethylene terephthalate (PTMT), preferably PTMT, based on the total weight of the polyester filaments The winding process and the POY polyester filament obtained by the said process are related. The invention also relates to a process of stretching texturing spun and wound polyester filaments and the bulky polyester filaments obtained thereby.

1 is a graph depicting the change in evaporation shrinkage for three PTMT POY bobbins as a function of storage period under standard conditions.

2 is a schematic of the force-extension diagram of PTMT POY.

1 shows the change in evaporation shrinkage for three PTMT POY bobbins as a function of storage period under standard conditions. The three bobbins examined had different initial values. Bobbins # 16,17 with a high initial value greater than 40% have an evaporation shrinkage of at least 30%, preferably at least 40% after 4 weeks. However, when the initial evaporation shrinkage value is less than 40%, as shown by bobbin 18, after 4 weeks of storage the evaporation shrinkage value will drop below the threshold value of 30%.

2 is a schematic of the force-extension diagram of the PTMT POY. For the same cut elongation, Fig. 2a) shows a diagram with a natural draw ratio (NDR) of at least 15% according to the invention, and Fig. 2b) shows a diagram with NDR = 0%. Evaporation shrinkage is a measure of the processability and crystallinity of the fiber. The fibers described in WO 01/04393 comprise plastics with relatively high crystallinity, which are difficult to process and can only be processed at low draw rates and / or low texturing speeds.

It is an object of the present invention to provide a process for spinning and winding POY polyester filaments in which at least 90% by weight of the total weight of the filaments is PBT and / or PTMT, in which the production and winding of POY polyester filaments is simple. More particularly, the POY polyester filaments should have cut elongation values ranging from 90% to 165%, high uniformity for filament parameters, and low crystallinity.

It is also an object of the present invention to provide an economical industrial process for spinning and winding POY polyester filaments. The process of the invention preferably allows very high spinning initial rates of greater than 2200 m / min, high yarn weight of packages of 4 Kg or more.

It is also an object of the present invention to improve the shelf life of POY polyester filaments obtained by the process of the present invention. The filament should be able to be stored for an extended period of time, for example four weeks. Ideally, the package should not shrink and harden on the winding mandrel to form a saddle with a hard edge and a concave center portion, so that there is no problem when unwinding the filament from the package.

According to the invention, the POY polyester filaments should be simple to process in a draw or draw-texturing action, preferably at higher texturing speeds, preferably above 450 m / min. The filaments obtained by stretch texturing must have excellent physical properties, for example, cutting strengths above 26 cN / tex and high cutting elongation above 30% for HE filaments or above 36% for SET filaments.

Other objects, which are not directly mentioned, but which are inferred or apparent from the relevant issues discussed at the outset, are achieved by a process for spinning and winding that includes all the features of claim 1. Advantageous variations of the process according to the invention are protected by the dependent claims accompanying the claim 1. POY polyester filaments obtained by the spinning process are described in the independent claim of the article. Stretch texturing of POY polyester filaments is claimed in method claim 6, and claims 7 and 8 of the article relate to bulky filaments obtained by stretch texturing.

The present invention thus provides for the production and winding of POY filaments comprising at least 90% by weight of polybutylene terephthalate (PBT) and / or polytrimethylene terephthalate (PTMT), preferably PTMT, of the total weight of the polyester filaments It provides a process for:

a) setting the draw ratio of the spinning line in the range of 70 to 500,

b) as soon as the filament exits the spinneret, passes through a 30 mm to 200 mm long quench delay zone,

c) cool the filament below the solidification temperature,

d) converge the filament at a distance between 500 mm and 2500 mm from the bottom face of the spinneret,

e) the yarn tension is set between 0.05 cN / dtex and 0.20 cN / dtex, preferably 0.15 cN / dtex, above and between the starting godets,

f) wound yarn with a yarn tension between 0.025 cN / dtex and 0.15 cN / dtex,

g) a step of setting the winding speed between 2200m / min and 3500m / min.

This unpredictable process provides POY polyester filaments that retain their excellent properties even after four weeks of storage at standard conditions. No significant drop in the uniformity value of the yarn due to aging is observed, nor shrinkage of the spun fiber on the bobbin.

At the same time, the process of the present invention has the following additional advantages.

The present invention is simple and economical to implement on a large industrial scale. More particularly, the process allows spinning and winding at high starting speeds of at least 2200 m / min and allows for the production of packages having a high yarn weight of at least 4 Kg.

The process of the invention makes it possible to omit the use of spinning additives. As a result, polyester filaments can be obtained particularly economically.

In addition, the POY polyester filaments obtainable by this process can be processed on a simple, economical and large industrial scale by stretching or stretching texturing operations. In this operation, the texturing can be performed at speeds in excess of 450 m / min.

Thanks to the high uniformity of the POY polyester filaments obtainable by the process, good package formation is simply achieved which ensures further processing of the POY polyester filaments and uniform and substantially defect free dyeing.

The filaments obtained by the stretching texturing have high cutting strength of 26 cN / tex or higher and high cutting elongation of 30% or more for HE filament and 36% or more for SET filament.

The present invention provides a process for the production and winding of POY polyester filaments having at least 90% by weight of polybutylene terephthalate (PBT) and / or polytrimethylene terephthalate (PTMT), based on the total weight of the filaments. Polybutylene terephthalate (PBT) and / or polytrimethylene terephthalate (PTMT) are known to those skilled in the art. Polybutylene terephthalate (PBT) is obtained by polycondensation of the same molar amount of 1,4-butanediol as terephthalic acid, and polytrimethylene terephthalate is obtained by polycondensation of terephthalic acid with the same molar amount of 1,3-propanediol Obtained. Also conceivable are mixtures of the two polyesters. According to the invention, PTMT is preferred.

The polyester may be homopolymers or copolymers. Useful copolymers are in particular repeating units of conventional comonomers, such as ethylene glycol, diethylene glycol, tri, as well as PTMT and / or PBT repeat units, based on all repeat units of polyester. Copolymers comprising ethylene glycol, 1,4-cyclohexanedimethanol, polyethylene glycol, isophthalic acid and / or adipic acid. However, for the purposes of the present invention, polyester homopolymers are preferred.

The polyesters of the present invention may be added in conventional amounts of additional additives such as catalysts, stabilizers, antistatic agents, antioxidants, flame retardants, dyes, dye adsorption improvers, light stabilizers, organic phosphites, optical brighteners and matting agents. May be included as a mixture. The polyester preferably comprises 0 to 5% by weight of additives based on the total weight of the filaments.

The polyester may further comprise a small fraction of branching components, preferably up to 0.5% by weight based on the total weight of the filaments. Preferred branching components according to the invention are polyfunctional acids such as trimellitic acid, or pyromellitic acid, or trivalent to hexavalent alcohols such as trimethylolpropane, pentaerythritol, dipentaerythritol, glycerol Or hydroxyacids thereof.

Polyesters useful in the present invention are preferably capable of being formed thermoplastic and can be spun and wound into filaments. In this description, particularly advantageous polyesters have a limited viscosity number in the range from 0.70 dl / g to 0.95 dl / g.

In the process of the present invention, the melt or melt mixture of polyester is pumped into a spinneret pack by a spin pump at a constant rate calculated by a known formula such that the required linear density of the fiber is obtained, so that the die plate of the pack Extruded through holes in the plate to form molten filaments.

The melt can be prepared, for example, from polymer chips in an extruder, in which case it is preferred that the chips are first dried such that the moisture content is below 30 ppm, in particular below 15 ppm.

Generally referred to as spinning temperature, the temperature of the melt measured above the spinning pump depends on the melting point of the polymer or polymer blend used. The spinning temperature is preferably located in the range given by the following formula (1).

Formula 1:

T _m + 15 ° C ≤ T _Sp ≤T _m + 45 ° C

Where T _m is the melting point of the polyester [° C]

T _Sp is the spinning temperature [° C.].

Characterized parameters serve to limit hydrolysis and / or thermal viscosity decomposition, which is preferably very low. In the context of the present invention, viscosity decomposition smaller than 0.12 dl / g, in particular smaller than 0.08 dl / g, is preferred.

Melt homogeneity has a direct impact on the properties of the spun filament. It is therefore desirable to use a static mixer with at least one element installed below the spinning pump to homogenize the melt.

The die plate temperature, which depends on the spinning temperature, is adjusted by the plate's second heating system. Useful second heating systems include, for example, radiation beams heated by "Diphyl" or additional convection or radiation heaters. The temperature of the die plate is typically equal to the spinning temperature.

The temperature increase at the die plate can be obtained through the pressure gradient of the spinneret pack. Known origin, for example, K. Riggert's "Fortschritte in der Herstellung von Polyester-Reinfenkordgarn" Chemiefasern 21, page 379 (1971), describes a temperature increase of about 4 ° C. for every 100 bar pressure drop.

Loose filter media, in particular through steel sand having an average particle size between 0.10 mm and 1.2 mm, preferably between 0.12 mm and 0.75 mm and / or from metal fabrics or nonwovens having fineness of up to 40 μm It is also possible to adjust the die pressure by using a filter disc.

In addition, the pressure drop at the die hole also contributes to the overall pressure. The die pressure is preferably set between 80 and 450 bar, in particular between 100 and 250 bar.

The elongation ratio i _Sp of the spinline, i.e. the ratio of the starting speed to the extrusion rate, is calculated from the density of the polymer or polymer mixture, spinneret hole diameter and the filament linear density via Equation 2 below according to US Patent 5,250,245.

Formula 2:

i _Sp = 2.2510 ⁵ · (δ · π) D ² (cm) / dpf (den)

(here

δ is the density of the melt for ^{PTMT = 1,12g / cm 3 [g} / cm 3];

D is the spinneret hole diameter [cm]

dpf is denier per filament [den].)

For the purposes of the present invention, the radial line stretch ratio is between 70 and 500, preferably between 100 and 250.

The ratio of length / diameter of the spinneret hole is preferably chosen to be between 1.5 and 6, in particular between 1.5 and 4.

The extruded filament passes through the cooling delay zone. The cooling delay zone is formed as a recess just below the spinning pack, in which the filaments emanating from the spinning holes are protected from the direct action of the cooling gas and the elongation or cooling of the spinning line is delayed. An active portion of the recess is constructed as an extension of the radiation pack into the radiation beam so that the filaments are surrounded by the heated wall. The passive portion is formed by the insulating layers and the frame not heated. For a total length of 30 to 200 mm, preferably 30 to 120 mm, the length of the active recess is between 0 and 100 mm and the length of the inactive part is between 20 and 120 mm.

As an alternative to the active recess, a reheater may be installed below the radiation beam. In contrast to the active recess, this zone of circular or rectangular cross section comprises at least one heating system independent of the radiation beam.

In the case of a radially porous cooling system around the spinning line, the cooling delay can be achieved using cylindrical shrouds.

The filament is then cooled below the solidification temperature. For the purposes of the present invention, the solidification temperature is the temperature at which the melt goes into the solid state.

In the context of the present invention, it has been determined that it is particularly advantageous to cool the filaments to a temperature at which the filaments are substantially no longer tacky. It is particularly advantageous to cool the filaments below their crystallization temperature, and more advantageously to cool them below their glass transition temperature.

Means for cooling or cooling the filaments have been known from the prior art. Particularly useful is the use of cooling gases, in particular cooling air, according to the invention. The temperature of the cooling air is preferably in the range of 12 ° C to 35 ° C, particularly in the range of 16 ° C to 26 ° C. The speed of the cooling air is advantageously in the range of 0.20 m / sec to 0.55 m / sec.

The filaments can be cooled using a single end system comprising, for example, a single cooling tube with a perforated wall. Cooling of each individual filament is obtained through an active cooling air supply or using the self-suction effect of the filament. As an alternative to individual tubes, it is also possible to use well known crossflow cooling systems.

In a particular embodiment of the cooling and spinning line extension zone, the filaments emerging from the delay zone are exposed to cooling air in a zone 10 to 175 cm long, preferably 10 to 80 cm long. Zones of 10 to 40 cm length are particularly suitable for filaments having a winding line density of 1.5 dtex or less per filament, and zones of 20 to 80 cm length are particularly suitable for filaments having a linear density between 1.5 and 9.0 dtex per filament. The filament and the accompanying air are then jointly controlled at a rate of 0.2-20: 1, preferably 0.4-5: 1, in the ratio of the velocity of air to the radiating line velocity at the start, to control the compression of the cross section The conveying direction is made to a specific dimension, passing through the channel with a reduced cross section.

After the filaments have cooled to a temperature below the solidification point, they converge to form a bundle of yarns. Suitable distances from the lower face of the spinneret according to the invention to the point of convergence can be achieved by conventional online measuring methods of yarn speed and / or yarn temperature, for example a laser Doppler anemometer from TSI of Germany or a type IRRIS 160 infrared camera from Goratec of Germany Can be determined using. The suitable distance is in the range of 500 to 2500 mm, preferably in the range of 500 to 1800 mm. The filaments having a linear density upon spinning of 4.5 dtex or less are preferably converged into the multifilament bundle at a distance of 1500 mm or less, and thicker filaments are preferably converged at a larger distance.

For the purposes of the present invention, it is advantageous for all surfaces in contact with the spun filament to be woven, especially with low-friction materials. This substantially prevents cutting of the filament and provides a high quality filament yarn. The low friction surface of "TriboFil" in the specification of Ceramtec of Germany is particularly suitable for this purpose.

The filaments converge into a lubricator pin that supplies the amount of spin finish required for the yarn at a uniform rate. Particularly suitable oil supply pins are characterized by inserts, yarn ducts with oil insert orifices and outlets. The insert is like a funnel to prevent contact with yet dry filaments. The point of contact of the filament takes place inside the yarn duct after the spinning finish has been supplied. It is adapted to the line density of the yarn duct and oil insertion orifice or yarn and the number of filaments. Particularly suitable are widths and orifices of 1.0 mm to 4.0 mm. The outlet of the lubricator fin is preferably formed as a homogenization zone, and includes an oil reservoir. Such oilers can be obtained from Ceramtec, Germany or Goulston, USA.

Uniformity of oil application is very important in the present invention. Uniformity can be determined using a Rosa meter, for example by the method described in Chemiefasern / Textilindustrie, 42/94 November 1992, page 896. Such a process preferably provides a standard deviation value of less than 90 digits, in particular less than 60 digits, for the application of oil. For the application of oil a standard deviation value of less than 45 digits, in particular less than 30 digits, is particularly preferred for the purposes of the present invention. Standard deviation values of 90 or 45 digits correspond to a coefficient of variation of approximately 6.2% or 3.1%, respectively.

Since gas bubbles can cause significant fluctuations in the application of oil, it is desirable for the purposes of the present invention to design the spin finish line and pump to be self-degassing to prevent gas bubbles. Do.

According to the invention, the filaments are preferably entangled sufficiently before the yarns are wound. In the context of the present invention, it has been found that jets with closed yarn ducts are particularly suitable, as the jet system prevents yarn rubbing in the feed slot even at low yarn tension and high air pressure. Entangling jets are preferably installed between the bars and the escape tension of the yarn is controlled through different speeds of the insert and outlet bars. The escape tension of the yarn should not exceed 0.20 cN / dtex and should essentially be between 0.05 cN / dtex and 0.15 cN / dtex. Entangled air pressure is between 0.5 and 5.5 bar, or up to 3.0 bar for winding speeds of 3500 m / min.

The yarn is preferably entangled with a node count of at least 10 n / m. Maximum nodule spacing less than 100 cm and nodule count variation values below 100% are particularly advantageous. The use of air pressures above 1.0 bar is advantageous in providing nodule numbers of 15 n / m or more, which is characterized by high uniformity with a coefficient of variation not greater than 70% and a maximum nodule spacing of 50 cm. In practical use, LD type systems from Temco, Germany, dual systems from Slack & Parr, USA, or polyjets from Heberlein have been found to be particularly useful.

The speed of the circumference of the first bar portion is called the starting speed. An additional bar system may be employed before the yarn is wound in the winding assembly for forming a package (bobbin) on the formers.

A stable, defect free package is the basic prerequisite for yarn free winding and ideal processing without ideal bonding. Therefore, in the context of the present invention, winding tensions in the range of 0.025 cN / dtex to 0.15 cN / dtex, preferably in the range of 0.03 cN / dtex to 0.08 cN / dtex, are employed.

An important parameter in the process according to the invention is the tension of the yarn set above the starting bar and between the starting bar. As will be seen in the future, this tension consists mainly of Hamana's actual orientation tension, the friction tension on the yarn guide and the lubricator, and the yarn-air friction tension. For the purposes of the present invention, the yarn tension between the starting bar and between the starting bar is in the range of 0.05 cN / dtex to 0.20 cN / dtex, preferably in the range of 0.08 cN / dtex to 0.15 cN / dtex.

Extremely low tension below 0.05 cN / dtex does not provide the required degree of partial orientation. When the tension exceeds 0.20 cN / dtex, this tension will induce a memory effect leading to deterioration of the parameters of the yarn during winding and storage of the bobbin.

According to the present invention, the tension is adjusted by the distance of the lubricator from the jet spinneret, the friction surface, and the length of the gap between the lubricator and the starting bar. This length is advantageously less than 6.0 m, preferably less than 2.0 m, and the spinning system and the starting machine are installed in a parallel configuration such that the yarns have a straight path.

Geometrical parameters also describe the adjustment time of the yarn between the convergence point and the winding point. Rapid relaxation during this period affects the quality of the package being molded. The defined adjustment time is preferably chosen to be between 50 and 200 ms.

The winding speed of the POY according to the invention is between 2200 m / min and 3500 m / min. The process according to the invention is advantageously carried out by controlling the environment of the yarn package so that the temperature is below 45 ° C., in particular between 12 ° C. and 35 ° C., and the relative humidity is between 40 and 85%. POY is preferably stored at a temperature of 45 ° C. or lower before further processing. It is further advantageous that the POY package is stored for at least 4 hours at a temperature of 12-35 ° C., 40-85% relative humidity before further processing.

After being stored for 4 weeks under standard conditions, the filaments according to the invention have the following properties.

a) cutting elongation between 90 and 165%, preferably between 90 and 135%,

b) evaporation shrinkage of at least 30%, preferably at least 40%,

c) less than 1.1%, preferably less than 0.9%, of normal Uster,

d) birefringence between 0.030 and 0.058,

e) density less than 1.35 g / cm ³ , preferably less than 1.33 g / cm ³ ,

f) a cut load variation coefficient of 4.5% or less, preferably 2.5% or less,

g) a coefficient of cut elongation variation of 4.5% or less, preferably 2.5% or less.

The term "standard conditions" is known to those skilled in the art and is defined through the DIN 53802 standard. Under “standard conditions” according to DIN 53802, the temperature is 20 ± 2 ° C. and the relative humidity is 65 ± 2%.

It is particularly advantageous for the purposes of the present invention that the evaporation shrinkage is between 50 and 65%, as measured immediately after winding, and at least 30%, preferably at least 40%, after storage for 4 weeks under standard conditions. Surprisingly it was determined that POY bobbins produced in this way have excellent additional process properties.

In industrial applications, it should be borne in mind that standard conditions cannot always be observed during the manufacture, storage or transport of POY. However, fibers with low crystallinity can often cause problems with changes in the shape of POY bobbins, draw ratios and / or texturing rates should be reduced and the occurrence of cut ends in subsequent processes increases. Yarns consistent with the above description of evaporative shrinkage are less concerned with such problems than conventional yarns.

It was further determined that the yarns of the present invention preferably exhibit no change in depth of shade on the DTY even after a two month shelf life. If the ambient temperature is below 45 ° C., the color change is within 95 ± 3% after a 20 month storage period.

Moreover, the filaments preferably have a natural draw ratio not less than 15%. It is more preferable that the natural draw ratio is in the range of 18 to 65%. The higher the natural draw ratio, the better the drawability. For the same elongation, higher natural draw rates will result in higher draw rates.

The natural draw ratio is defined as the portion of the plateau in the percent diagram of force-elongation. This parameter is known and determined by the stretch tester in one operation with determination of strength and elongation.

2a) and 2b) are schematic depictions of the parameters of the indicated natural draw ratio (NDR) (although the natural draw ratio in FIG. 2b) is zero. Each diagram is a diagram of the force on the kidney, and the diagram is schematically drawn so that the parameters can be expressed.

It is believed that the natural draw ratio is a measure of fiber orientation, and that the NDR value of less than 15% describes the onset of crystallization of the polyester. Low NDR values are obtained, for example, by heat treating the fibers prior to winding at a temperature at least 8 ° C. above the glass transition temperature of the PES.

Methods of determining the indicated material parameters are well known to those skilled in the art. These methods can be recognized from the technical literature. Although most parameters can be determined in a variety of ways, the following method for determining filament parameters will prove particularly advantageous for the purposes of the present invention.

Intrinsic viscosity is measured at 25 ° C with a Ubbelohde customs viscometer and is calculated using a known formula. The solvent used is a 3: 2 mixture by weight / weight ratio of phenol and 1,2-dichlorobenzene. The concentration of the solution is 0.5 g of polyester per 100 ml solution.

Melting point, crystallization temperature and glass transition temperature are determined using a DSC calorimeter from Mettler, respectively. The sample is initially heated to 280 ° C. for melting and then cooled. DSC measurement is performed at a heating rate of 10 K / min in the range from 20 ° C to 280 ° C. The reported temperature is determined by the processor.

Filament density is determined in a density gradient column at a temperature of 23 ± 0.1 ° C. n-heptane (C ₇ H ₁₆ ) and methane tetrachloride (CCl ₄ ) are used reagents. The result of the density measurement can be used to calculate the degree of crystallinity based on the density D _a of the amorphous polyester and the density D _k of the crystalline polyester. The calculation is described in the literature and in the case of PTMT, for example, the corresponding values are D _a = 1.295 g / cm ³ and D _k = 1.429 g / cm ³ .

Linear density is a known method, where precision reels and weighing materials are determined by means of a weighing mean. The pretension used is advantageously 0.05 cN / dtex for POY and 0.2 cN / dtex for DTY.

Cutting strength and cutting elongation are determined using a Statimat device under the following conditions. Clamped length is 200mm for POY, 500mm for DTY, elongation speed is 2000mm / min for POY, 1500mm / min for DTY, pretension is 0.05cN / dtex for POY, DTY For 0.2 cN / dtex. The maximum cutting load value for determining the cutting strength is divided by the linear density, and the cutting elongation is determined at the maximum load.

Evaporation shrinkage is determined by treating the filament skein in tension without water for 10 ± 1 minutes at a temperature of 95 ± 1 ° C. The skein is prepared by winding at a pretension of 0.05 cN / dtex for POY and 0.2 cN / dtex for DTY. The length measurement of the skein before and after the heat treatment is performed at 0.2 cN / dtex. The difference in length is used to calculate evaporation shrinkage in a known manner.

Birefringence is determined as the method described in DE 19,519,898, the disclosure of which is hereby incorporated by reference.

The crimp parameters of the textured filaments are measured using a Texturmat device from Stein of Germany according to DIN 53840 Part 1 at a release temperature of 120 ° C.

Normal aster values are determined using a 4-CX aster tester and are reported as the aster% value. The test speed is 100 m / min and the test time is 2.5 minutes.

The POY according to the invention is simple for further processing, in particular for stretching texturing. In the present invention, the stretching texturing is preferably performed at a texturing speed of at least 500 m / min, particularly preferably 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. For example, it may be particularly advantageous to draw texturing on a high temperature heater type machine, such as Barmag's AFK machine.

The bulky filaments produced in this way show a low defect count and excellent color depth and color uniformity when dyed with a disperse dye (Terasil Navy) without carrier at a boiling point of 95 ° C.

Bulky SET filaments produced according to the present invention have a cut strength of at least 26 cN / dtex and a cut elongation of 36% or more. In the case of bulky HE filaments obtained without heat treatment in the second heater, the cut strength is preferably at least 26 cN / dtex and the cut elongation is at least 30%.

The bulk and elastic behavior of the filaments according to the invention is excellent.

The present invention is not limited to these embodiments, and embodiments according to the present invention will be described in more detail.

Examples 1 and 2

Spinning and winding

Melt viscosity (measured at 2.4Hz and 255 ° C) 325 Pa.s, intrinsic viscosity of 0.93dl / g, melting point of 227 ° C, crystallization temperature of 72 ° C and glass transition temperature of 45 ° C, 11ppm moisture It was rolled at 130 ° C. to dryness and dried.

The chips are melted in a Barmag 3E4 extruder, bringing the melt to 255 ° C. The melt is fed to a spinning pump along a production line containing Sulzer's SMX static mixer with 15 elements and an inner diameter of 15 mm. The amount transferred of the melt is 63 g / min, which is combined with a residence time of 6 minutes and the metered amount from the spin pump to the spinneret pack is 30.7 g / min. Various winding speed settings are used. An element of Fluitec's HD-CSE type static mixer with an internal diameter of 10 mm is installed below the spinning pump but above the point of entry into the spinneret pack. The second heating system for the production line and the spin block, including the pump and spinneret pack, was set at 255 ° C. The spinneret pack includes 30-mm height 350-500 μm steel sand, and a 20 μm nonwoven filter and a 40 μm fabric filter as filter media. The melt is extruded through an 80 mm diameter spinneret plate with 34 holes having a diameter of 0.25 mm and a length of 1.0 mm. The pressure of the die is 120 bar.

The cooling delay zone is 100 mm long, 30 mm made of heated walls and 70 mm made of insulated and unheated frames. The molten filaments are cooled through air flowing horizontally with respect to the spin line over a length of 1500 mm. Cooling air has a temperature of 18 ° C., a relative humidity of 80%, and a flow rate of 0.35 m / sec. The filaments solidify at a distance of about 800 mm below the spinneret.

A yarn lubricator located at a distance of 1050 mm from the spinneret is used to apply the spin finish before the ends converge. The lubricator has a TriboFil surface and an insertion opening with a diameter of 1 mm. The amount of spin finish applied is 0.40% based on the mass of the fibers.

The converged spinning line is then fed to the winding machine. The distance between the refueling price and the first departure bar is 3.2m. The adjustment time is 144 ms or 168 ms depending on the speed. Yarn is wrapped in a S shape by a pair of bags. Temco entanglement jets are located between the bars, which are operated using an air pressure of 1.5 bar. Consistent with the speed setting, the winding speed of the Barmag SW6 winder is set such that the tension of the winding yarn is 5 cN. Room conditions are adjusted to 24 ° C., 60% relative humidity, resulting in an environment of yarn package of about 34 ° C.

In the context of the test, the starting speed is 2940 m / min (Example 1) or 2506 m / min (Example 2). Table 1 shows the different experimental parameters and Table 2 shows the properties of the obtained POY filaments. In both settings, 10 kg bobbin weight is producible and can be easily removed from the winding mandrel.

Experimental parameters Experimental parameters Example 1 Example 2 Departure speed [m / min] 2940 2506 Winding speed [m / min] 2926 2500 Radiation Line Elongation Rate 178 152 Yarn tension -1 from above [cN] 14 10 Bar to 1 (maximum value) [cN] 11 7.5 -2 from above [cN / dtex] 0.13 0.08 Bar to 2 (maximum value) [cN / dtex] 0.10 0.06 Yarn Tension1 [cN] 5.0 5.0 Yarn Tension 2 [cN / dtex] 0.048 0.041

1: absolute value

2: based on linear density

Properties of PTMT POY Filament 1 Properties Example 1 Example 2 Linear density [dtex] 105 123 Cutting strength [cN / dtex] 23.4 20.7 Cutting kidneys [%] 98 127 Normal Uster [%] 0.9 0.76 Evaporative shrinkage [%] 46 33 Birefringence10 ³ Δn 52 43 density [g / cm ³ ] 1.320 1.318 Cutting load CV [%] 2.2 1.9 Cutting kidney CV [%] 2.2 1.9

CV: coefficient of variation

1: Value measured after 4 weeks of storage under normal conditions

Stretch Texturing

PTMT filament bobbins are stored for 4 weeks under the standard conditions defined in DIN 53802 before being passed on to the Barmag FK6-S-900 stretch texturing machine. Experimental parameters for stretch texturing to produce SET filaments are summarized in Table 3 and the properties of bulky SET filaments by the stretch texturing results are summarized in Table 4.

Texturing defects were determined using Barmag's UNITENS system at the following limit values: UP / LP = 3.0cN, UM / LM = 6.0cN.

Experimental Parameters of Stretch Texturing Experimental parameters Example 1 Example 2 speed [m / min] 700 700 Elongation ratio 1: 1.48 1: 1.65 D / Y ratio 2.1 2.1 Temperature of heater 1 [℃] 155 155 Temperature of heater 2 [℃] 160 160 Texturing Defects [n / 10 km] 0 0 Yarn tension F ¹ _{, on} assembly [cN] 20 20 F ² , under assembly [cN] 19 18 F ² -CV [%] 1.2 1.3

F ² -CV: is the coefficient of variation of F ²

Properties of Stretched Textured Filaments Properties Example 1 Example 2 Linear density [dtex] 78 82 Cutting strength [cN / tex] 27.7 29.0 Cutting kidneys [%] 39.4 39.9 Dyeability Uniformity Uniformity Crimp rigidity [%] 85 87 Crimp shrinkage [%] 24.5 25

The bulk behavior can be changed by coldly operating the second heater, ie by producing so-called HE filaments. The crimp shrinkage then increases by about 47%. The cut elongation then decreases by 33%.

The present invention relates to the spinning of POY polyester filaments comprising at least 90% polybutylene terephthalate (PBT) and / or polytrimethylene terephthalate (PTMT), preferably PTMT, by weight based on the total weight of the polyester filaments And a POY polyester filament obtained by the winding step and the step. The invention also makes use of spun and wound polyester filaments in a stretch texturing process and the bulky polyester filaments obtained thereby.

Claims (8)

At least 90% by weight of polybutylene terephthalate (PBT) and / or polytrimethylene terephthalate (PTMT), based on the total weight of the polyester filament, is produced and wound up to produce a POY polyester filament comprising PTMT As a method, a) setting the stretching ratio of the spinning line in the range of 70 to 500, b) passing the filament through a quench delay zone 30 mm to 200 mm long as soon as it exits the spinneret, c) cooling the filament below a solidification temperature, d) converging the filaments at a distance between 500 mm and 2500 mm from the bottom face of the spinneret, e) setting the yarn tension between 0.05 cN / dtex and 0.20 cN / dtex between the starting godets and above the starting bar, f) winding the yarn with a yarn tension between 0.025 cN / dtex and 0.15 cN / dtex, and g) a method of producing and winding POY polyester filament, comprising the step of setting the winding speed between 2200 m / min and 3500 m / min. The process of claim 1 wherein PBT and / or PTMT are used, which have a limiting viscosity value from 0.7 dl / g to 0.95 dl / g. A method according to claim 1 and / or 2, wherein the winding step is carried out by setting the ambient environment of the yarn package to a temperature of 45 ° C. or less. The POY polyester filament of claim 1, wherein the POY bobbin is stored for at least 4 hours at 12-35 ° C. and 40-85% relative humidity prior to subsequent processing. How to wind up by. POY polyester filament obtainable by the process claimed in at least one of the preceding claims, after the filament has been stored for four weeks under the standard conditions defined in DIN 53802, a) cutting elongation between 90% and 165%, b) evaporation shrinkage of at least 30%, c) less than 1.1% of normal Uster, d) birefringence between 0.030 and 0.058, e) density less than 1.35 g / cm ³ , preferably less than 1.33 g / cm ³ , f) cutting load variation coefficient of less than 4.5%, g) POY polyester filament, having a coefficient of cut elongation variation of 4.5% or less. A process for the production of bulky polyester filaments, wherein the filament of claim 5 is treated in a draw-texturing machine at a speed of at least 500 m / min and a draw ratio of at least 1.35: 1 to yield a bulky yarn. Production method. A bulky polyester SET filament obtainable by the method of claim 6, wherein the cut strength of the filament is at least 26 cN / dtex and the cut elongation is at least 36%. A bulky polyester HE filament obtained by the method of claim 6, wherein the cut strength of the filament is 26 cN / dtex or more, and the cut elongation is 30% or more.