JP2014526621A - Poly (trimethylene arylate) fiber, method for making the same, and fabric made therefrom - Google Patents

Abstract

  Fine denier poly (trimethylene arylate) spun drawn fibers are characterized by a high degree of denier uniformity. Further disclosed is a method of making uniform fine denier yarn at a spinning speed of 4000-6000 m / min. The poly (trimethylene arylate) fibers herein contain from 0.1 to 3% by weight of polystyrene dispersed therein. Fabrics made from the fibers are also disclosed.

Description

  The present invention relates to a process for spinning poly (trimethylene arylate) fibers, the resulting fibers, and uses thereof.

  Poly (trimethylene arylate), in particular poly (trimethylene terephthalate) (also called 3GT, Triexta or PTT) has recently received much attention as a fiber-forming polymer useful in textiles. PTT fibers have excellent physical and chemical properties. Continuously textured polyester yarns made from partially oriented polyester yarns (POY) or spun drawn yarns (SDY), mostly polyethylene terephthalate (PET), such as knitted fabrics and woven fabrics and non-woven fabrics such as spunbond PET Widely used commercially in many textile applications. The textile term “yarn” refers to a bundle of individual fibers. For example, shirts and blouses are often made from yarns made up of bundles of 30-40 filaments.

  Polyester yarns, including both PET and PTT yarns, are made by a so-called melt spinning process and are said to be “melt spun”. Melt spinning is a process in which a polymer is melted and extruded from the so-called spinneret holes. In a typical textile application, the spinneret is provided with a plurality (often 30-40) of holes, each hole having a diameter of about 0.25 mm. Thereby, a large number of filaments are extruded from a single spinneret. These filaments are combined to form a bundle called a yarn.

  The polyester yarn can be used in any combination with or without other types of yarn. Thus, polyester yarn can make up the entire fabric, or it can constitute warp, weft or fill in a woven fabric, or, for example, cotton, wool, rayon, acetate, other polyesters, spandex It can also be used as one of two or more yarns in a yarn blend with and / or combinations thereof.

  U.S. Pat. No. 6,284,370 to Fujimoto et al. Discloses a method of making 1-2 dpf PTT fibers, where the first roll is heated to 30-80 ° C. and the second roll is Heated to 100-160 ° C., the stretch ratio imposed between the first roll and the second roll was in the range of 1.3-4. In 13 examples and 11 counterexamples, Fujimoto never heated the first roll to a temperature higher than 60 ° C, except for one counterexample. In all examples, the temperature of the first roll was in the range of 50-60 ° C.

  Ding U.S. Pat. No. 7,785,507 discloses a method for making 2-3 dpf PTT fibers, where the first godet is heated to 85-160 ° C. and the second godet is 125 The draw ratio heated between ˜195 ° C. and imposed between the first roll and the second roll was in the range of 1.1-2. Ding teaches that the first godet temperature of 75 ° C. caused excessive line breakage. The Uster result was about 0.90 to 0.95%. In all examples, the temperature of the first godet was 90 ° C. or higher.

  US Pat. No. 6,287,688 to Howell et al. Describes the production of textured PTT yarns that exhibit increased stretchability, luxurious bulk and improved feel compared to PET yarns. Howell et al. Describe the production of partially oriented PTT yarns at spinning speeds up to 2600 m / m. In contrast, PET is melt-spun on a daily basis at several times the speed. For cost reasons, it is highly desirable to be able to spin PTT yarns at speeds faster than 2600 m / min.

  US Pat. No. 6,923,925 to Chang et al. Describes a composition comprising PTT containing about 2% polystyrene (PS) that can be melt spun into a spun drawn yarn at a speed of up to 5000 m / min. Things are disclosed. Chang et al. Are completely silent with respect to the denier uniformity (denier CV) of the yarn so produced, and also with respect to the temperature of the godet roll used to make the spun drawn yarn.

  PTT's low denier spin-drawn filament yarns can be spun at commercially feasible spinning speeds and have sufficient denier uniformity to have particular utility in making high quality fabrics and garments. is necessary.

  In a first aspect, the present invention provides a filament comprising a composition comprising 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate) based on the total weight of the polymer in the composition. The filament is characterized in that the denier per filament is 3 or less, the denier coefficient of variation is 2.5% or less, and the birefringence is at least 0.055.

  In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  In another aspect, the present invention provides a novel method for forming a drawn drawn filament characterized by having a denier per filament of 3 or less and a coefficient of variation of denier of 2.5 or less. Contains from 0.1 to 3% by weight (based on the total weight of the polymer) of polystyrene dispersed in poly (trimethylene arylate) from an orifice having a cross-sectional shape where a continuous filamentary extrudate is formed. Extruding the polymer melt; quenching the extrudate to solidify into continuous filaments; and filaments in a first driven roll that is heated to a temperature in the range of 70-100 ° C. and rotated at a first rotational speed. After winding the filament, the filament is wound around the second driven roll that is heated to a temperature in the range of 100 to 130 ° C. and rotates at the second rotational speed. And winding the filament around a take-up roll at a linear speed of at least 4,000 meters / minute (m / minute), wherein the ratio of the first rotational speed to the second rotational speed is 1. A spun drawn filament with a denier per filament of 3 or less and a denier coefficient of variation of 2.5% or less is formed.

  In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  In another aspect, the invention provides a filament comprising a composition comprising 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate), based on the total weight of the polymer in the composition. The filament is characterized in that the filament has a denier per filament of 3 or less, a denier coefficient of variation of 2.5% or less, and a birefringence of at least 0.055.

  In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

1 is a schematic view of one embodiment of melt supply to a spinneret according to the present invention. FIG. 1 is a schematic view of an embodiment of a spinning method according to the present invention. 1 shows a loom suitable for producing a woven fabric of the present invention. It is the schematic of the spinning machine used in an Example. It is a graph of an experimental result, shows the effect of the temperature of the first godet on the denier coefficient of variation, and compares the result obtained using the spinning machine # 2 with the result obtained using the spinning machine # 1.

  In one aspect, the present invention relates to a filament comprising a composition comprising 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate) based on the total weight of the polymer in the composition. The filament has a denier per filament (dpf) of 3 or less, a denier coefficient of variation (denier CV) of 2.5% or less, and a birefringence of at least 0.055.

  In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  In one embodiment, the filaments herein are continuous filaments. In an alternative embodiment, the filaments herein are staple filaments. In one embodiment, the plurality of filaments herein are combined to form a multifilament yarn. The multifilament yarn thus formed is suitable for texturing and for final use in textile applications where fine denier yarn such as shirts, blouses, lingerie, socks, etc. is desirable.

  The multifilament yarns herein are useful for forming knitted fabrics, woven fabrics, and nonwoven fabrics by methods known in the art.

  In alternative embodiments, the filaments herein are also suitable for use in various types of nonwoven structures. The filaments herein can be arranged in a random or semi-random web to form a filament nonwoven. In a further embodiment, the filament nonwoven comprises a plurality of continuous filament strands herein. In an alternative further embodiment, the filament nonwoven comprises a single continuous filament strand. In an alternative embodiment, the filament nonwoven comprises a plurality of staple filaments made from the filaments herein. A filament nonwoven fabric for the purposes of the present invention is a nonwoven fabric whose basic structural elements are not single filament segments but single filament segments arranged randomly or semi-randomly.

  In another aspect, the present invention provides a novel method for forming a spun drawn filament, wherein the denier per filament is 3 or less and the coefficient of variation of denier is 2.5% or less. The method includes 0.1 to 3 weight percent (based on the total weight of the polymer) of polystyrene dispersed in poly (trimethylene arylate) from an orifice having a cross-sectional shape that forms a continuous filamentary extrudate. A step of extruding a polymer melt containing, a step of rapidly cooling the extrudate to solidify into continuous filaments, and a first driven roll that is heated to a temperature in the range of 70-100 ° C. and rotates at a first rotational speed. After winding the filament, the filament is wound around the second driven roll that is heated to a temperature in the range of 100 to 130 ° C. and rotates at the second rotation speed. And winding the filament onto a take-up roll at a linear speed of at least 4,000 meters / minute (m / minute), wherein the ratio of the first rotational speed to the second rotational speed is 1.75. Within the range of ~ 3.

  As demonstrated in the examples presented below, a yarn denier that is 3 dpf or less when the first godet is set above 70 ° C. when spun at a speed of 4,000 m / min or more. The CV is significantly lower than the denier CV of an equivalent composition yarn spun at the same speed when the first godet is set at a commercially typical temperature of 60 ° C.

  The term “denier coefficient of variation” (denier CV) refers to the coefficient of variation of denier as determined by the Uster Yarn Evenness tester available from Uster Technologies. The so-called “Uster tester” measures the variation of denier along the length of a single continuous strand of fiber or yarn. Denier CV is a standard statistical parameter and represents a value obtained by dividing the standard deviation of denier by the average denier determined from the Uster tester.

  In the present invention, unless otherwise stated, concentrations are stated in weight percentage units. In particular, the concentration of polystyrene blended with the poly (trimethylene terephthalate) or other poly (trimethylene arylate) herein is expressed as a weight percent of polystyrene relative to the total weight of polymer in the composition. Shall be understood.

  Where a numerical range is provided herein, it is to be understood to encompass the endpoints of the range, unless specifically stated otherwise. Numeric values should be understood to have the precision of the number of significant digits provided, as described in ASTM E29-08. For example, number 3 shall be understood to encompass a range of 2.5 to 3.4, while number 3.0 shall be understood to include a range of 2.95 to 3.04.

  For purposes of the present invention, unless otherwise stated explicitly, the description will be for embodiments where the poly (trimethylene arylate) is poly (trimethylene terephthalate) (PTT). The extension of the present invention to other poly (trimethylene arylates) is by adjusting the concentration by weight appropriate to the molecular weight difference of the specific arylate monomer units contained, assuming that the degree of polymerization is equal. Shall be done.

  Both polystyrene and PTT homopolymers and copolymers are suitable for use in the present invention. For the purposes of the present invention, the term “copolymer” shall be understood to encompass not only dipolymers but also terpolymers, tetrapolymers and the like. The term “copolymer” shall be understood to include any number of monomers polymerized together. In practice, the majority of applications are limited to homopolymers, dipolymers, and terpolymers.

  In one embodiment, the filament comprises a composition comprising 97-99.9 wt% PTT and 3-0.1 wt% polystyrene (PS). In another embodiment, the filament comprises a composition comprising 70-99.5 wt% PTT, 3-0.5 wt% PS, and optionally up to 29.5 wt% other polyester. In another embodiment, the filament comprises a composition comprising 98-99.5 wt% PTT and 2-0.5 wt% PS.

  In one embodiment, the filament consists essentially of a composition consisting essentially of 97-99.9 wt% PTT and 3-0.1 wt% polystyrene (PS). In another embodiment, the filament consists essentially of a composition consisting essentially of 70-99.5 wt% PTT, 3-0.5 wt% PS, and optionally up to 29.5 wt% other polyester. Become. In another embodiment, the filament consists essentially of a composition consisting essentially of 98-99.5 wt% PTT and 2-0.5 wt% PS.

  Suitable PTT polymers are formed by the condensation polymerization of 1,3-propanediol and terephthalic acid or dimethyl terephthalate. One or more suitable comonomers for copolymerization therewith are linear, cyclic, and branched aliphatic dicarboxylic acids or esters having 4 to 12 carbon atoms (eg, butanedioic acid, Pentanedioic acid, hexanedioic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid and their corresponding esters); aromatic dicarboxylic acids having 8-12 carbon atoms, other than terephthalic acid or esters, or Esters (eg, isophthalic acid and 2,6-naphthalenedicarboxylic acid); linear, cyclic, and branched aliphatic diols having 2 to 8 carbon atoms (other than 1,3-propanediol), such as Ethanediol, 1,2-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl 1,3-propanediol, 2-methyl-1,3-propanediol, and 1,4-cyclohexanediol; and aliphatic and aromatic ether glycols having 4 to 10 carbon atoms, such as hydroquinone bis It is selected from the group consisting of (2-hydroxyethyl) ether or poly (ethylene ether) glycol (including diethylene ether glycol) having a molecular weight of less than 460. The comonomer is usually present in the PTT copolymer at a level in the range of 0.5 to 15 mol% and can be present in an amount up to 30 mol%.

  The PTT can contain small amounts of other comonomers that are selected so as not to significantly affect the properties. Such other comonomers include, for example, sodium 5-sulfoisophthalate at a level in the range of 0.2 to 5 mole percent. Very small amounts of trifunctional comonomers, such as trimellitic acid, can be incorporated for viscosity control. PTT can be blended with up to 30 mole percent of other polymers. Examples include polyesters prepared from other diols such as those listed above.

  In one embodiment, the PTT contains at least 85 mol% trimethylene terephthalate repeat units. In a further embodiment, the PTT contains at least 90 mol% trimethylene terephthalate repeat units. In yet a further embodiment, the PTT contains at least 98 mol% trimethylene terephthalate repeat units. In yet a further embodiment, the PTT contains 100 mole% trimethylene terephthalate repeat units.

  In one embodiment, a suitable PTT is characterized by an intrinsic viscosity (IV) in the range of 0.70 to 2.0 dl / g. In a further embodiment, a suitable PTT is characterized by an IV in the range of 0.80 to 1.5 dl / g. In a still further embodiment, a suitable PTT is characterized by an IV in the range of 0.90 to 1.2 dl / g.

In one embodiment, a suitable PTT is characterized by a number average molecular weight ( _Mn ) in the range of 10,000 to 40,000 Da. In a further embodiment, a suitable PTT is characterized by a M _n in the range of 20,000 to 25,000 Da.

In one embodiment, the suitable polystyrene is selected from the group consisting of polystyrene homopolymers, α-methyl-polystyrene, and styrene-butadiene copolymers, and blends thereof. In one embodiment, the polystyrene is a polystyrene homopolymer. In a further embodiment, the polystyrene homopolymer is characterized by a M _n in the range of 5,000 to 300,000 Da. In a further embodiment, M _n of polystyrene homopolymer is in the range of 50,000～200,000Da. In a further embodiment, M _n of polystyrene homopolymer is in the range of 75,000～200,000Da. In yet a further embodiment, the _{Mn of the} polystyrene homopolymer ranges from 120,000 to 150,000 Da. Useful polystyrene can be isotactic, atactic, or syndiotactic. High molecular weight atactic polystyrene homopolymer is preferred.

  Polystyrene useful in the present invention is available from Dow Chemical Co. (Midland, Mich.), BASF (Mount Olive, NJ) and Sigma-Aldrich (Saint Louis, Mo.).

  PTT and PS are melt blended and then extruded in the form of strands and subsequently cut into pellets. Other forms of melt mixing and subsequent grinding into flakes, chips, powders or the like can also be performed. Under some circumstances, after making a pellet containing a first PTT / PS blend having a PS concentration higher than 15%, the pellet is remelted and the remelt is diluted with additional PTT, It may be convenient to form a second melt blend having a PS concentration of 3% or less and extrude the second melt blend into the filaments herein.

  The filament herein includes a composition comprising PTT and PS. In some embodiments, these are just two materials in the blend, which can be 100% by weight in total. In many cases, however, the blend can have other materials as commonly included in polyester polymer compositions for commercial use. Such additives include, but are not limited to, other polymers, plasticizers, UV absorbers, flame retardants, dyes, and the like. Thus, the sum of poly (trimethylene terephthalate) and polystyrene will not be 100% by weight. Other polymers can include, for example, polyamides that impart acid dyeability to the yarn blend. In the example where an additional non-polyester polymer is added, the ratio of the weight percent concentration of polyester to PS remains the same as the composition without other polymers.

  According to the present invention, PS is in the form of particles having an average size of less than 500 nanometers. In one embodiment, the polystyrene is a polystyrene homopolymer at a concentration of 2% or less, and the poly (trimethylene arylate) is a PTT containing at least 98 mol% trimethylene terephthalate monomer units.

  The filament of the present invention is characterized in that dpf is 3 or less, denier CV is 2.5% or less, and birefringence is at least 0.055. Typical physical properties of the filaments herein include toughness greater than 3 grams / denier and elongation at break of 30-70%. In one embodiment, the denier of the filament is 2.5 or less. In another embodiment, the birefringence is at least 0.060.

  In another aspect, the present invention relates to a method for making single or multifilament yarns: (a) making a melt blend consisting essentially of PTT and 0.1 to 3 wt% (wt%) polystyrene (PS). And (b) melt spinning the polymer melt blend so produced to form one or more filaments of PTT containing dispersed PS.

  The filaments of the present invention are conveniently made as spun drawn filaments (ie, filaments that are fully drawn in the spinning process). Completely stretched means that the filament after quenching extends to near its ultimate elongation until breakage. Preferably, spinning includes extruding the polymer blend herein through a spin speed of at least 4,000 m / m from one or more holes in the spinneret. The term “spinning speed” refers to an accumulation speed of the spun fiber in a mechanical winding device or the like.

  The high birefringence of 0.055 or more characteristic of the filaments of the present invention is a direct result of the high degree of drawing applied to the filaments in the spin-draw process. High birefringence is the principle method of distinguishing between spin-drawn filaments and partially oriented spun yarns that are later drawn-textured.

  FIG. 1 is a schematic diagram of one embodiment of a melt spinning machine suitable for use in the present invention. Referring to FIG. 1, PTT is produced in a continuous melt polymerization apparatus 1, from which it is conveyed in a molten form through a transfer line 2 to a counter-rotating twin screw extruder 3, and the twin screw extruder is provided with a mixing zone. It has been. At the same time, the pellets containing PS are fed to the satellite extruder 5 by means of a weight-loss feeder 4 or other pellet feeder means, where the pellets are melted and in the mixing zone of the twin screw extruder 3 or upstream thereof. Then, it is supplied to the twin screw extruder 3 through the transfer line 6 in a molten form. In a twin screw extruder, a PTT / PS melt blend is formed. The resulting melt blend is fed through a transfer line 7 to a spinning block 8 containing a spinneret, from which one or more continuous filaments 9 are extruded.

  FIG. 2 shows one suitable configuration for melt spinning in accordance with the present invention. 34 filaments 22 (not all 34 filaments are shown) are extruded from the hole spinneret 21. The filament passes through the cooling zone 23, is formed into a yarn bundle, and passes through the finishing applicator 24. The cooling zone includes an air quench zone where air strikes the yarn bundle at a rate of 40 feet / minute at room temperature and 60% relative humidity. The air quenching zone is for so-called cross-air quenching (air flows across the yarn bundle) or so-called radial quenching (air source is in the center of the converging filament and flows radially outwards over 360 °) Can be designed for. Radial quenching is a more uniform and effective quenching method. After finishing applicator 24, the yarn is connected to a separator roll and set to 60-100 ° C (in one embodiment, 70-100 ° C), a first driven godet roll 25, also known as a supply roll. Moved to. The yarn is wound 6 to 8 times around the first godet roll and separator roll. The yarn is transferred from the first godet roll to a second driven godet roll, also known as a draw roll, connected to the second separator roll and set at 110-130 ° C. The yarn is wound 6 to 8 times around the second godet roll and separator roll. The speed of the drawing roll is 4000 to 6000 m / min, and the ratio of the drawing roll speed to the supply roll speed is in the range of 1.75 to 3. The yarn is transferred from the draw roll to a third driven godet roll 27 connected to a third separator roll, which is operated at room temperature and at a speed 1-2% faster than the roll speed of the second godet roll. The yarn is wound 6-10 times around the third roll pair. The yarn passes from the third roll pair through the interlace nozzle 28 and then is moved to a hoisting device 29 that is operated at a speed consistent with the output of the third roll pair.

  Referring to FIG. 2, in accordance with the process herein, the quenched filaments are drawn on the first godet roll so that the extruded filament is drawn down by the first godet roll prior to quenching. It is wrapped around the circumference at least once (but preferably multiple times). Downstream of the first godet roll, the filament is at least once around the second godet roll so that the second godet exerts a drawing force on the portion of the filament between the first godet roll and the second godet roll. Wrapped (but preferably multiple times). In the embodiment shown in FIG. 2, the filaments move from a second godet roll to a third godet roll that operates at a rate 1-2% faster than the second (stretched) godet roll and acts as a let-down roll. Oriented. The filament is directed from the third godet to the winding device. The speed at which the filament is wound around the winding device is described as the spinning speed. In a typical installation, the hoisting device is a tension-controlled hoisting device.

  According to the present invention, the first godet roll is heated to a temperature in the range of 70-100 ° C, and the second godet roll is heated to a temperature in the range of 100-130 ° C. The first godet roll is driven at a first rotational speed, and the second godet roll is driven at a second rotational speed. According to the present invention, the ratio of the second rotational speed to the first rotational speed (stretch ratio) is in the range of 1.75-3.

  In one embodiment, each of the plurality of filaments of the present invention is individually extruded from a multi-hole spinneret. The so extruded filaments are combined to form a yarn. Typically, yarns are tied together by applying some agitation, twisting, or both of extruded filaments, or thread lines, to cause entanglement of the filaments. The yarn so formed comprises a plurality of filaments, each filament having a dpf of 3 or less, a denier CV of 2.5% or less, and a birefringence of at least 0.055. . In one embodiment, the denier of the filament is 2.5 or less. In another embodiment, the birefringence is at least 0.060. Typical yarns include 34, 48, 68, and 72 filaments, but the number of filaments that are combined to make the yarn is in no way limited.

  The yarns formed according to the present invention are not limited to those composed of a plurality of filaments according to the present invention, but may contain other filaments as well. For example, yarns formed in accordance with the present invention can contain other polyesters and polyamides, other filaments of polyacrylates, and other filaments as may be desired. The other filament may be a staple fiber.

  Yarns formed in accordance with the present invention (which can be formed by the spin-draw process described above) are false twisted as commonly practiced to provide textile-like aesthetics to continuous polyester fibers. Suitable for use as supply yarn for. Although there are several types of texturing devices (all well known in the art), the texturing process comprises: a) providing a yarn package as formed according to the spinning process described above; (b) Unwinding the yarn from the package; (c) passing the end of the yarn through a frictional twisting element or false twisting spindle; and d) rotating the spindle, thereby heating the yarn upstream of the rotating spindle with heating. Twisting and unwinding upstream downstream of the rotating spindle and (e) winding the yarn around the package.

  The present invention allows increased productivity in spinning fine denier (3 dpf or less) spin-drawn PTT yarn. The filaments of the present invention and their yarns were made at spinning speeds 30-70% higher than the maximum spinning speed achievable with neat PTT. The resulting yarn has an elongation and toughness that is within 20% of the elongation and toughness of a PTT multifilament yarn that differs from the yarn of the present invention only in that it does not contain PS (and is not necessarily spun at about 3000 m / min). Features. Thus, yarns consisting essentially of the filaments of the present invention are useful in various types of textile applications, with only the fine tuning required by the textile machinery used. The resulting yarn is useful under the same or similar conditions as used for PTT yarns made at 3000 m / min without PS, especially in making textured yarns, fabrics and carpets It is.

  In the filaments of the present invention, PTT is a continuous phase, or “matrix”, and PS is a discontinuous phase dispersed within the PTT matrix. In one embodiment, the size of the PS particles dispersed in the PTT matrix is 500 nm or less. In a further embodiment, the size of the PS particles dispersed in the PTT matrix is 200 nm or less.

  Beneficial features of the present invention include the ability to spin fine denier high strength and tough spun drawn PTT yarns at spinning speeds of 4000 m / min or higher. These beneficial features depend on both the fine particle size of the PS and the volume homogeneity of the dispersion of the PS in the PTT, which in turn depends on the application of a sufficiently high shear melt mixing. There is no threshold particle size at which the spinning performance and / or physical properties of the spun yarn are suddenly reduced. Rather, the performance gradually decreases as the PS particle size increases. For particle sizes in the range of 500 nm or more, the denier CV gradually increases. Similarly, there is no specific threshold of homogeneity for particle distribution in the PTT matrix. The better the uniformity of dispersion, the more uniform the resulting spun filament. One particularly valuable benefit of the present invention is the production of spin-drawn yarns characterized by a denier CV of less than 2.5%. Low denier CV is particularly important in making fine denier yarns for textile applications. Denier CV below 2.5% unless the process in which PS is dispersed in PTT is characterized by sufficient shear force to ensure particle size less than 500 nm and sufficiently high uniformity of dispersion Is very unlikely.

  The amount of shear force applied to the melt depends on the rotational speed of the mixing element, the viscosity of the melt, and the residence time of the melt in the mixing zone. If the shear force is too low, the PS will not disperse from the beginning or will tend to agglomerate rapidly into droplets of a size larger than 500 nm.

  The melt mixing process can be carried out both batchwise and continuously. So-called high shear mixers, as commonly used in the polymer compounding art, are suitable. Examples of suitable commercially available high shear batch mixers include, but are not limited to, Banbury mixers and Brabender mixers. Examples of continuous high shear mixers include, but are not limited to, a co-rotating twin screw extruder and a Farrel continuous mixer. A counter-rotating twin screw extruder is also suitable. In general, a suitable high shear mixer is one that can provide a minimum shear rate of 50 / s (preferably 100 / s) to the polymer melt. After melt mixing, the resulting blend can be pelletized for later feeding to the spinning machine, or the melt blend can be fed directly to the spinning machine. Another useful method is to bind the polymer melt. An example of this method is to provide the PTT melt from the continuous polymerizer to the first stage of the twin screw extruder and feed the PS melt from the satellite extruder to the mixing zone of the twin screw extruder, thereby melting Would form a blend. Alternatively, the unmelted polymer can be dry mixed, such as by tumbling, before being fed to a twin screw extruder for melt mixing.

  An average particle size greater than 500 nm is not preferred from the viewpoint of good fiber spinning performance. Furthermore, the spinning of filaments that are uniform along a single warp and between warps is clearly dependent on the homogeneity of the volume distribution of the PS particles. While not limiting the scope of the invention in any way, it is assumed that in its actual melting process, the PS particles melt and form molten droplets that are dispersed within the molten PTT matrix.

  The temperature in the melt mixer must be above the melting point of both PTT and PS and below the lowest decomposition temperature of any of the materials. The specific temperature may depend on the specific attributes of the polymer used. In a typical implementation, the melting temperature is in the range of 200 ° C to 270 ° C.

  In one embodiment, the concentration of PS in the PTT / PS blend pellet is in the range of 0.5-1.5%.

  As shown in FIG. 1 and as is generally true for polymer fiber melt spinning, the polymer melt is fed to the spinneret through a transfer line. The melt flow from the extruder to the transfer line is in a turbulent state. However, the spinneret feed must be laminar to achieve a uniform flow through the plurality of holes in the spinneret. Within the transfer line, the melt flow transitions from turbulent flow to laminar flow.

  Filament spinning can be accomplished using conventional equipment and procedures that are widely used commercially. In practice, for fine denier filament spinning of 3 dpf or less, a PS concentration higher than 3% is found to result in a decrease in the mechanical properties of the fiber so produced. Furthermore, at 5% PS, it is found that fine denier filaments cannot be melt spun at all.

  Prior to melt spinning, the polymer blend pellets are preferably dried to a moisture level of less than 30 ppm to avoid hydrolysis during melt spinning. Any means for drying known in the art is sufficient. In one embodiment, a closed loop hot air dryer is used. Usually, PTT / PS blends are dried for 6 hours with dew points below 130 ° C and -40 ° C. The PTT / PS polymer blend thus dried is melt spun into fibers at 250-265 ° C.

  In a typical melt spinning process, one embodiment of which is described in detail below, dry polymer blend pellets are fed to an extruder, which melts the pellets and provides the resulting melt to a metering pump To do. The metering pump delivers a volumetrically controlled polymer flow through the transfer line to the heated spin pack. The pump must provide a pressure of 10-20 MPa to drive its flow through a spin pack containing filtration media (eg, sand bed and filter screen) to remove any particles larger than a few micrometers. Don't be. The mass flow rate through the spinneret is controlled by a metering pump. At the bottom of the pack, the polymer exits into the air quench zone through a plurality of small holes in a thick metal plate (spinneret). Although the number of holes and their dimensions can vary greatly, typically a single spinneret hole has a diameter in the range of 0.2-0.4 mm. Spinning is advantageously achieved at a spinneret temperature of 235-295 ° C, preferably 250-290 ° C.

  Typical flow rates through holes of that size tend to be in the range of 1-5 g / min. A number of cross-sectional shapes are used for the spinneret holes, but a circular cross-section is most common. Usually, the line speed is controlled by a highly controlled rotating roll system in which the spun filaments are wound. The diameter of the filament is determined by the flow rate and the winding speed, and does not depend on the size of the spinneret hole.

  The properties of the filaments thus produced are determined by the dynamics of the threadline, particularly in the region known as the quench zone between the exit from the spinneret and the freezing point of the filament. The specific design of the quench zone, the air flow across the emerging yet viable filament, has a huge impact on the properties of the quenched filament. Both cross-flow type quenching and radiant quenching are generally used. After quenching or solidification, the filament moves at the take-up speed, which is usually 100 to 200 times faster than the exit speed from the spinneret hole. Thus, significant acceleration (and elongation) of the thread line occurs after emerging from the spinneret hole. The amount of orientation frozen in the spun filament is directly related to the stress level in the filament at the freezing point.

  The melt spun filaments produced thereby are collected to match the desired end use. For example, in the case of filaments intended to be converted into staple fibers, a plurality of continuous filaments can be combined into a tow, and the tow is collected in a so-called pidding can. Filaments intended for use in a continuous form, such as texturing, are typically wound on a yarn package attached to a tension-controlled winding device. According to the invention, the accumulation rate is at least 4,000 m / min.

  Texture processing imparts crimp by twisting, heat setting, and untwisting through a process commonly known as false twisting. These multifilament yarns (also known as “bundles”) contain the same number of filaments as the spun drawn yarns from which they are made. Thus, they preferably contain at least 10 and even more preferably at least 25 filaments, usually containing up to 150 or more, preferably up to 100, more preferably up to 80 filaments. can do. The yarn usually has a total denier of at least 1, more preferably at least 20, preferably at least 50, more preferably at most 250, and at most 1,500. The filament is preferably at least 0.1 dpf, more preferably at least 0.5 dpf, more preferably at least 0.8 dpf, and most preferably at most 3 dpf.

  PTT staple fibers are obtained by melt spinning a PTT / PS blend into filaments at a temperature of 245-285 ° C., quenching the filaments, drawing the quenched filaments, crimping the drawn filaments, It can be made by cutting into staple fibers having a length of 0.2 to 6 inches (0.5 to 15 cm). One preferred process includes: (a) providing a polymer blend comprising PTT and 0.1-3% PS; and (b) melt spinning the melt blend into a filament at a temperature of 245-285 ° C. (C) quenching the filament, (d) stretching the quenched filament, and (e) 8-30 crimps / inch (3-12 inches) using a mechanical crimper. Crimping the drawn filaments at a crimp level of (crimp / cm); (f) relaxing the crimped filaments at a temperature of 50-120 ° C .; and (g) relaxing the filaments. Cutting into staple fibers having a length of preferably 0.2 to 6 inches (0.5 to 15 cm). In one preferred embodiment of this process, the drawn filaments are annealed at 85-115 ° C. prior to crimping. Preferably, the annealing is performed with tension using a heated roller. In another preferred embodiment, the drawn filaments are not annealed before crimping. Staple fibers are useful in making textile yarns and textiles or nonwovens, and can also be used for fiber fill applications and carpet manufacturing.

  Although the present invention will be described primarily with reference to multifilament yarns, it should be understood that the priorities described herein are also applicable to monofilaments.

  Filaments can be circular, or octalobal, delta, sunburst (also known as the sun), scalloped oval, trilobal, tetra-channel (also known as 4-channel), It can also have other shapes such as scalloped ribbons, ribbons, stars. These can be solid, hollow or multi-hollow.

  In another aspect, the invention provides a filament comprising a composition comprising 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate), based on the total weight of the polymer in the composition. The filament is characterized in that the filament has a denier per filament of 3 or less, a denier coefficient of variation of 2.5% or less, and a birefringence of at least 0.055. In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  In one embodiment, the filaments are bundled into yarn and the fabric is a woven fabric. In an alternative embodiment, the filaments are bundled into at least one yarn and the fabric is a knitted fabric. In yet another embodiment, the fabric is a nonwoven fabric, and in a further embodiment, the fabric is a spunbond fabric.

  In one definition, a nonwoven fabric is a fabric that is not woven or knitted. Woven and knitted structures are characterized by a regular pattern of meshed yarns made either by interlacing (woven fabric) or looping (knitted fabric). In either case, the yarn follows a regular pattern that is repeated many times from one side of the fabric to the other and in the opposite direction. The integrity of the woven or knitted fabric is formed by the structure of the fabric itself.

  In nonwovens, most commonly, the filaments are laid down in a random pattern and bonded together by chemical or thermal means rather than mechanical means. One commercially available example of a non-woven fabric produced by such means is Sonara® spunbond polyester available from DuPont Company. In some cases, the nonwoven fabric does not include interlacing or looping and the fibers are staggered from one side to the other as described in US Pat. No. 6,579,815 to Popper et al. Can be produced by laying down the layers of fibers in a complex three-dimensional topological arrangement.

  The woven fabric is made of a plurality of yarns that are interlaced orthogonally to each other. Yarns parallel to the length of the fabric are called "warp yarns" and yarns orthogonal to the direction are called "filling" or "wefts". Each warp is called a “warp” (end). As seen in any fabric or clothing store, the specific method by which the yarn is interlaced, the denier of the yarn, both the tactile and visual beauty of the yarn itself, the density of the yarn, and the ratio of warp to weft By changing, you can achieve a huge variation of beauty. In general, the structure of the woven fabric imparts a certain amount of rigidity to the fabric, and the woven fabric generally does not stretch as much as the knitted fabric.

  In the woven fabric of the present invention, at least a portion of the warp comprises 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate) based on the total weight of the polymer in the composition. A filament containing filaments, wherein the filament has a denier per filament of 3 or less, a denier coefficient of variation of 2.5% or less, and a birefringence of at least 0.055. To do. In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  In one embodiment, both the warp and the weft include a yarn comprising the filaments herein. In one embodiment, the warp includes at least 40% (by number) of yarns comprising the filaments herein and at least 40% (by number) of cotton yarns. In one embodiment, the warp comprises at least 80% (by number) of yarns comprising the filaments herein and the weft comprises at least 80% cotton. Generally, greater physical requirements are imposed on warps than wefts.

  Woven fabrics are manufactured on a loom as they have been manufactured for thousands of years. Although the loom has undergone major changes, the basic principles of operation remain the same. FIG. 3a is a schematic view of an embodiment of a loom and is shown in a side view. A warp beam 31 composed of a plurality (often hundreds) of parallel warp yarns 32 is arranged as a supply device for the loom. The warp beam 31 is shown in front view in FIG. 3b. FIG. 3a shows a loom with two harnesses. Each of the harnesses 34a and 34b is a frame that holds a plurality (often hundreds) of so-called “hooks”. Referring to FIG. 3 c, which shows a front enlarged view of the harness 34, each ridge 311 is a vertical wire with a hole 312 in it. The harness is arranged to move up and down, and when one moves up, the other moves down. A portion 33a of the warp is passed through a hole 312 in the heel 311 of the upper harness 34a, and another portion 33b of the warp is passed through a hole in the heel of the lower harness 34b, so that there is a gap between the warps 33a and 33b. Can be opened. In a loom of the type shown, the shuttlecock 36 is propelled by means not shown (usually a wooden paddle) and moves or reciprocates left and right as the harness moves up and down. The shuttlecock has a bobbin for the weft yarn 37. When the shuttlecock moves through the gap between the warp yarns, the weft yarn 37 is unwound. The so-called “lead” or “筬” 35 is a frame that holds a series of vertical wires, through which the warp passes freely. FIG. 3d shows a front view of the lead 35, in which a vertical wire 313 and a space 314 through which the warp passes are drawn. The thickness of the vertical wire 314 determines the warp spacing and thereby the warp density in the cross direction of the fabric. The lead plays a role of pushing the newly inserted weft to the right in the figure and pushing it into a predetermined position of the fabric 38 being formed. The fabric is wrapped around the fabric beam 310. The roll 39 is a guide roll.

  The winding of the warp beam is usually done by attaching as many yarn packages or spools as the desired number of warp yarns to a so-called creel, each warp being fed to the warp beam through a series of precise guides and tensioners, and then warp beam It is an accurate operation that is rolled up all at once.

  The particular pattern of interlacing, the warp to weft ratio, determines the type of woven fabric produced. Basic putters include plain weave, oblique weave, and satin weave. Many other more decorative textile patterns are also known.

  Knitting is the process by which a fabric is made by looping one or more yarns together. Knitted fabrics tend to be more elastic and elastic than woven fabrics. Knitted fabrics tend to be less durable than woven fabrics. There are numerous knitting patterns and knitting styles, as in the case of textiles. According to the present invention, in one embodiment, the fabric herein comprises 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate), based on the total weight of polymer in the composition. A filament comprising a yarn comprising a filament comprising a composition comprising: a filament having a denier per filament of 3 or less, a denier coefficient of variation of 2.5% or less, and a birefringence of at least 0.055 It is characterized by being. In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  Also contemplated in the present invention is a garment sewn from the fabric of the present invention. The garment herein includes a filament comprising a filament comprising a composition comprising 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate), based on the total weight of the polymer in the composition. The filament is characterized by having a denier per filament of 3 or less, a denier coefficient of variation of 2.5% or less, and a birefringence of at least 0.055. In one embodiment, the poly (trimethylene arylate) is poly (trimethylene terephthalate).

  The production of garments from fabrics is a very well known technique. Fabrication from fabric is usually required by creating a pattern from paper or in computerized form for automated processes, measuring the required piece of fabric, and cutting the fabric Making a fabric piece and then sewing the fabric pieces according to a pattern. The garment may be made from only one or more styles of the fabric of the present invention. Alternatively, the garment may be made by combining one or more styles of the fabric of the present invention with other fabrics.

  The invention is further described in the following specific embodiments, but is not limited thereto.

Test Method Intrinsic Viscosity The intrinsic viscosity (IV) of PTT was determined using Viscotek Forced Flow Viscometer Y900 (Viscotek Corporation, Houston, Tex.). The viscosity was determined by forming a 0.4 g / dl PTT solution in a solvent mixture of 50/50 wt% trifluoroacetic acid and methylene chloride at 19 ° C. according to the procedure of ASTM D-5225-92. These IV measurements were correlated with IV values measured manually in 60/40 wt% phenol / 1,1,2,2-tetrachloroethane according to ASTM D4603-96.

Number Average Molecular Weight The number average molecular weight of polystyrene was determined according to ASTM D5296-97. The same method was used for poly (trimethylene terephthalate) except that the calibration standard was poly (ethylene terephthalate) with a M _w of 44,000 and was a hexafluoroisopropanol solvent.

Toughness and elongation at break The physical properties of filaments and yarns are described in Instron Corp. Tensile Tester Model No. Measured using 1122. More specifically, the elongation at break _Eb and toughness were measured according to ASTM D-2256.

Effect of spinning machine on spinning campaign and results Fiber spinning was carried out in four separate campaigns. As described in more detail below, campaigns # 1, 3, and 4 were run on spinning machine # 2, and campaign # 2 was run on spinning machine # 1.

  The results obtained from Spinner # 1 are interspersed as shown in Table 4 and FIG. 5, and are not considered definitive. In particular, the denier coefficient of variation was higher than the limit specified in the present invention and did not appear to systematically change with the temperature of the first godet.

  FIG. 5 is a graph showing denier CV versus first godet temperature, where the data from campaigns 1, 3 and 4 are all plotted together in a diamond, and the data from campaign # 2 is a triangle. Used in the graph. As shown in Tables 3-6 below, the data points obtained in the three campaigns using Spinner # 2 were not all obtained using the same set of spinning conditions. Nevertheless, as can be seen in FIG. 5, the data from Spinner # 2 shown in diamonds is clear that the first godet temperature in the range of about 75-85 ° C. corresponds to the minimum value of denier CV. Showed a trend. A similar trend was not observed in Campaign # 2 data.

  Denier coefficient of variation is a measure of short range denier variability, which in turn is an indicator of the stability of the melt spinning process. The melt spinning process can be unstable because the spinning composition causes instability. It can also be unstable because the machine is unstable. In this case, it is clear from FIG. 5 that the high denier CV that occurred in Campaign # 2 was a machine performance and design artifact.

  Spinner # 1 was a laboratory built spinner equipped with only the most basic equipment to effect melt spinning. Spinner # 1 was usually used only to obtain the most basic information about whether the experimental composition could be melt spun into fibers. In the campaign # 2 in this specification, the spinning machine # 1 was used because the spinning machine # 2 could not be used on the day when the campaign # 2 was scheduled due to scheduling confusion. Spinner # 2 was a pilot plant spinning line. The conditions there were fully scalable to a full size commercial scale spinning line. This was the spinning line selected to demonstrate the difference in results that is characteristic of the present invention.

  FIG. 4 schematically shows the spinning machine # 2. The dry resin blend pellets were supplied by weight to the single screw extruder 42 by the silo dryer 41. The output of the single screw extruder 42 was supplied directly to the input of a gear pump 43 provided with an overflow port 44 under pressure. The output of the gear pump was fed to a spin pack 46 at six ends (of which four ends were used) via a short (including long) transfer line 45. Each of the four thread lines 47 (one shown) was extruded from its 36-hole spinneret (not shown). Each hole in the spinneret was characterized by a circular cross section of 0.27 mm diameter and a length of 0.50 mm. Each thread line 47 passes through a cross-flow quench air zone 48 of length 1.75 m in Campaign 1 where ambient air flows from one side to the other across the thread line. The ambient air passed through a radial quench air zone 48 of about 1.75 m in length that flowed radially around the threadline to produce an even more uniform filament. Each of the rapidly cooled thread lines is brought into contact with the finishing roll 49, and then wound around the first heating godet (supply roll) 410 and the corresponding first separator roll 411 6 to 8 times. The line was held apart. The thread line was then directed through an interlace nozzle (not shown) to a second heated godet (stretching roll) 412 and a second corresponding second separator roll 413 and to a hoisting device 414. Although not shown, each godet was partially surrounded by a hot chest to maintain temperature. The extruder was provided with three heating zones and an output zone head zone.

  Spinner # 1 and Spinner # 2 were substantially identical with respect to the layout described in FIG. One difference was that the quench air chimney of spinner # 1 was much narrower than its equivalent in spinner # 2.

  In all examples and comparative examples, the average result of four thread lines spun simultaneously under each condition set is reported. After changing the setpoint conditions, the spinning machine was allowed to reach a steady state by running for about 45 minutes before making the test sample. When changing the composition of the polymer, the spinner was purged with PTT containing no PS. When changing the spinneret, the machine was purged between spinning experiments.

Preparation of polymer blends Samples of PS (0.8 and 0.55 wt%) in PTT were made by co-feeding dry PTT and PS to a 30 mm T / S extruder. Sorona® Semi-Dull PTT resin pellets (1.02IV, available from DuPont Company, Wilmington, DE) Polytrimethylene terephthalate in polystyrene (168M KG 2, available from BASF) in the amounts shown in Table 1. Mixed with pellets. Prior to use, the PTT was dried in a 120 ° C. vacuum oven with a nitrogen purge for 14 hours. The two polymers were individually weighted into the fourth barrel section of the Werner & Pfleiderer ZSK-30 counter rotating twin screw extruder. The feed rates used are shown in Table 1 in pounds per hour (pph). The extruder had a 30 mm diameter barrel built with 13 barrel sections, with two kneading zones and three conveying sections arranged in an alternating arrangement, and the extruder had an L / D ratio of 32 . Each barrel section was heated independently. Sections 1-4 were set at 25 ° C, sections 5-13 were set at 210 ° C, and a 3/16 inch strand die was also set at 210 ° C. A vacuum was applied to the barrel segment 8. Table 1 also shows the feed composition, output speed, and melting temperature. The extrudate was quenched in water immediately after exiting the die and then pelletized into 1/8 inch pellets using a standard pelletizer.

Melt spinning Fiber melt spinning was carried out in four separate spinning campaigns described below. Table 2 shows the spinning parameters held constant during each campaign.

Campaign # 1-spinning machine # 2
The so-prepared PTT / PS blend melt blended pellets were dried in a dry silo at 140 ° C. overnight to reduce the moisture content to less than 50 ppm. The dried melt blend was weight fed to the single screw extruder of FIG. The set point (° C.) of the extruder was 230/255/263 in zones 1 to 3, respectively. The output of the extruder was melted and fed to the spin pack through a gear pump. The spin pack has six spinning positions, four of which have spinnerets, each spinneret has 36 holes, each hole is 0.27 mm in diameter and 0.5 mm in length, circular It had a cross section. Each yarn so produced was a 75 denier 36 filament yarn. The settings for the first godet roll are shown in Table 3. Note that the second godet roll was held at 110 ° C. and 4500 rpm. The quenching air was a cross flow type quenching with an air velocity of 0.35 cm / s.

  The protocol followed was as follows: the second godet roll (stretching roll) was set to 4500 m / min and 110 ° C. and was not changed during the course of the experiment. Next, an experiment was conducted with the first godet roll (feed roll) set to 60 ° C., and the stretch ratio that provides the highest toughness when the elongation at break was adjusted to be in the range of 55 to 65% was identified. Changed the speed. For polymer blend # 2 (0.055% PS), a draw ratio of 2.09 provides maximum toughness when the elongation at break is within the desired range (ie, the feed roll was set at 2150 m / min). It was found to bring. The spinning was then continued at additional feed roll temperatures of 85 and 110 ° C. Following the same procedure for polymer blend # 1 (0.8% PS), the stretch ratio of 2.37 was highest when the elongation at break was in the desired range (ie, feed roll speed = 1900 m / min) Found to provide toughness.

  The results are shown in Table 3.

Campaign # 2-spinning machine # 1
0.80 wt% new melt blend in PTT identical to blend # 1 above. The so-prepared PTT / PS blend melt blended pellets were dried in a dry silo at 140 ° C. overnight to reduce the moisture content to less than 50 ppm. The dried melt blended pellets were weight fed to the single screw extruder of FIG. The set point (° C.) of the extruder was 230/255/263 in zones 1 to 3, respectively. The output of the extruder was melted and fed to the spin pack through a gear pump. The spin pack has six spinning positions, four of which have spinnerets, each spinneret has 36 holes, each hole is 0.27 mm in diameter and 0.5 mm in length, circular It had a cross section. Each yarn so produced was a 75 denier 36 filament yarn. The settings for the first godet roll are shown in Table 4. Note that the second godet roll was held at 110 ° C. and 4500 rpm. The quenching air was a cross flow type quenching with an air velocity of 0.35 cm / s.

  The protocol followed was as follows: the second godet roll (stretching roll) was set to 4500 m / min and 110 ° C. and was not changed during the course of the experiment. Next, an experiment was conducted with the first godet roll (feed roll) set to 60 ° C., and the stretch ratio that provides the highest toughness when the elongation at break was adjusted to be in the range of 55 to 65% was identified. Changed the speed. Following for polymer blend # 1 (0.8% PS), a draw ratio of 2.37 is the highest toughness when the elongation at break is within the desired range (ie, first godet roll speed = 1900 m / min) Found to bring.

  Examples 5 and 6 were performed using a spinneret orifice with a diameter of 0.27 mm. Examples 7 and 8 were carried out using a spinneret orifice with a diameter of 0.32 mm. Other spinning conditions are shown in Tables 2 and 4. The results are shown in Table 4.

Campaign # 3-spinning machine # 2
The same batch of PS / PTT containing 0.80 wt% PS as used in Campaign # 2 was used.

  In these examples, 75 denier / 36 filament yarn was spun and melted using the same spinning machine procedure and settings described for Campaign # 1 above, except that the quench was a radial quench. Spinning was performed. The spinning conditions are shown in Tables 3 and 5. Again, the heating zone of the extruder was set to 230/255/263 ° C., respectively. The diameter of the spinneret was 0.27 mm. The flow rate was controlled at 37.5 g / min. The results are shown in Table 5.

Campaign # 4-spinning machine # 2
A third blend of 0.8% PS in PTT was made in the same manner as blend # 2 above.

  In these examples, melt spinning was performed using the same spinning machine procedure and settings as described for Campaign # 3 except that 75 denier / 72 filament yarn was spun. The spinning conditions are shown in Tables 3 and 6. Again, the heating zone of the extruder was set to 230/255/263 ° C., respectively. The diameter of the spinneret was 0.27 mm. Except as noted in Example 12 and Example 13, the flow rate was controlled at 37.5 g / min. The results are shown in Table 6.

Claims (6)

  A filament comprising a composition comprising from 0.1 to 3 weight percent polystyrene dispersed in poly (trimethylene arylate) based on the total weight of the polymer in the composition, wherein the denier per filament is A filament characterized in that it has a denier coefficient of variation of 2.5% or less and a birefringence of at least 0.055.   The filament according to claim 1, wherein the poly (trimethylene arylate) is poly (trimethylene terephthalate).   The filament of claim 1, wherein the composition comprises 0.5-2 wt% polystyrene dispersed in poly (trimethylene arylate) based on the total weight of the polymer in the composition.   The composition of claim 3, wherein the composition consists essentially of 0.5 to 2 wt% polystyrene dispersed in poly (trimethylene arylate), based on the total weight of the polymer in the composition. Filament.   The filament according to claim 2, wherein the composition comprises 0.5-2 wt% polystyrene dispersed in poly (trimethylene terephthalate) based on the total weight of the polymer in the composition.   3. The composition of claim 2, wherein the composition consists essentially of 0.5-2% by weight polystyrene dispersed in poly (trimethylene terephthalate), based on the total weight of the polymer in the composition. filament.

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