KR20140093992A - Process for preparing bicomponent fibers comprising poly(trimethylene terephthalate) - Google Patents

Abstract

A process for producing a spiral-wound bicomponent fiber from two poly (trimethylene terephthalate) materials which differ in their intrinsic viscosity is disclosed. One material is characterized by an intrinsic viscosity of ≤ 0.7 dL / g. The relatively low intrinsic viscosity allows for the adoption of low melting temperatures, without significant degradation of the properties or processability of bicomponent fibers, accompanied by a decrease in the incidence of acrolein.

Description

PROCESS FOR PREPARING BICOMPONENT FIBERS COMPRISING POLY (TRIMETHYLENE TEREPHTHALATE) <br> <br> <br> Patents - stay tuned to the technology PROCESS FOR PREPARING BICOMPONENT FIBERS COMPRISING POLY (TRIMETHYLENE TEREPHTHALATE)

The present invention relates to a melt spinning process for the production of bicomponent fibers comprising poly (trimethylene terephthalate).

Melt spun bicomponent fibers are well known in the art. They are particularly useful in the art to form high bulk fibers and yarns in particular. Bicomponent fibers are formed when two or more melt streams comprising different polymers are combined in a spinneret to form a single fiber. Crimped fibers can be made from bicomponent fibers having a side by side or eccentric sheath / core structure when the two polymers making up the two components differ in shrinkage properties have. When such as-spun bicomponent fibers are typically treated by heat treatment to cause shrinkage of the fibers, a different degree of shrinkage causes the fibers to take on a spiral shape, thereby creating a crimp configuration. The two components of the polymer may be chemically distinct, such as bicomponent fibers where one component is poly (ethylene terephthalate) and the other component is poly (trimethylene terephthalate) (PTT). Alternatively, the two components may be the same chemically, but with different physical properties related to shrinkage.

U.S. Patent No. 7,147,815 (Chang et al.) Includes a second composition comprising a first fiber component comprising a first composition comprising a first poly (trimethylene terephthalate) (PTT) and a second PTT Wherein the first and second PTTs differ from each other by an intrinsic viscosity of from 0.03 to 0.5 dL / g. Chang employs PTT materials characterized by an IV ranging from 0.86 to 1.01 dL / g. The window has the advantage of adopting a melting temperature of up to 270 ° C to reduce the content of IV of 0.86 dL / g IV to 0.70 dL / g in the melt stream of one component in order to achieve high crimp contraction Teach.

JP 2000256918A (Yoshimura et al.) Discloses a process for producing a three-functional copolymer having one side comprising (A) at least 85 mol% of poly (trimethylene terephthalate) and the other side of (B) At least 85 mol% of poly (trimethylene 30 terephthalate) copolymerized with the monomer; (C) has an inherent viscosity of not less than (A), and the other side contains (C) 85 mol% or more of poly (trimethylene terephthalate) which is not copolymerized with the 3-functional comonomer. 0.15 to 0.30 less) discloses a core-sheath type or a parallel type bicomponent fiber.

In one aspect, the present invention provides a bicomponent fiber consisting essentially of a first poly (trimethylene terephthalate) fiber component and a second poly (trimethylene terephthalate) fiber component, wherein the bicomponent fiber is> 2.2 Characterized in that the first fiber component and the second fiber component are arranged in relation to one another in a configuration suitable for the occurrence of crimp in the bicomponent fiber, characterized by a molecular weight distribution representing the polydispersity index of the fibers and an intrinsic viscosity in the range of 0.72 to 0.84 do.

The present invention relates to a process for producing a first poly (trimethylene terephthalate) material, characterized by melting a first poly (trimethylene terephthalate) material characterized by an intrinsic viscosity of? 0.7 dL / g to form a first molten stream characterized by a melting temperature below 250 ° C, 1 the melt stream is characterized by a lower intrinsic viscosity of less than 0.03 dL / g less than the intrinsic viscosity of the first material; Characterized in that a second poly (trimethylene terephthalate) material, characterized by an intrinsic viscosity of> 0.7 dL / g, is melted to form a second molten stream, wherein the difference between intrinsic viscosities of the first and second molten streams &Gt; 0.1 dL / g; Providing the first and second melt streams to a spinneret to contact the first melt stream with the second melt stream therein; Extruding molten fibers from the spinneret; And forming a solid bicomponent fiber characterized by a first component and a second component disposed relative to each other in a configuration suitable for forming the crimps by quenching the molten fibers, And the like.

&Lt; 1 >
1 is a schematic diagram of a bicomponent fiber spinning configuration suitable for the process of the present invention.
2,
Figure 2 is a schematic view of a device suitable for use in drawing, annealing, and winding bicomponent fibers produced during the process of the present invention.
3,
Figure 3 is a schematic view of a resin melting and feeding system suitable for use in the process of the present invention.

When a range of values is provided herein, it is intended to include the endpoints of that range unless specifically stated otherwise. The numerical values used herein have the precision of the number of significant digits provided in accordance with the standard protocol in chemistry for the significant digits as outlined in ASTM E29-08 Section 6. For example, number 40 includes the range of 35.0 to 44.9, while number 40.0 includes the range of 39.50 to 40.49.

As used herein, "bicomponent fibers" refers to fibers that have a fiber cross-section, for example, a parallel, eccentric core, or other pair of cross- &Lt; / RTI &gt;

Unless otherwise indicated, reference to "poly (trimethylene terephthalate)" (PTT) is intended to include homopolymers and copolymers containing more than 70 mol% of trimethylene terephthalate repeating units.

PTT is prepared by polycondensation of dimethyl terephthalate, or the corresponding diacid and 1,3-propanediol. A suitable copolyester can be prepared by adding a third reactant to the polymerization reaction. The third component may be an additional diastereomer or diacid, or an additional glycol. The comonomer is typically present in the copolyester at a level in the range of from about 0.5 to about 15 mole percent, and may be present in an amount up to 30 mole percent. Preferably, the PTT is a homopolymer.

Suitable PTTs may contain minor amounts of other comonomers, and such comonomers are typically chosen such that they do not have significant deleterious effects on the properties. These other comonomers include 5-sodium-sulfoisophthalate, for example, at levels ranging from about 0.2 to 5 mole%. For example, a very small amount of a trifunctional comonomer, such as trimellitic acid, for viscosity control.

The molecular weight of the PTT can be determined by any of a variety of methods. One such method which is commonly employed in the art of polyester polymers is the measurement of the so-called intrinsic viscosity (IV). The IV of the polymer is determined by extrapolating the measured solution viscosity of the polymer to the zero concentration of the polymer. The intrinsic viscosity thus determined was determined by the Mark-Houwink equation as described in Polymer Chemistry, 5 ^th ed., By Charles E. Carrahar, Marcel Dekker (2000) (M _w ). There are some discrepancies in the art regarding the notation "IV" in solution viscosity of the polymer. It is understood in the art that in some cases "IV" refers to the so-called "logarithmic viscosity &quot;, which is related to intrinsic viscosity but not to intrinsic viscosity. For purposes of the present invention, the abbreviation "IV " will always refer to the intrinsic viscosity.

Another way to determine the molecular weight is by so-called size-exclusion chromatography (SEC). Suitable methods for performing SEC on the polymers of the present invention are provided below. SEC has the advantage of defining the overall molecular weight distribution, while the intrinsic viscosity defines a single point in its distribution. The ratio of weight average molecular weight (M _w) to number average molecular weight (M _n) is known as the polydispersity index (PDI) of the polymer, which is an index of the molecular weight distribution width. It is known that the polycondensation reaction, such as those employed in the manufacture of PTT, exhibits a PDI of about 2.0 ± 0.1.

The intrinsic error in the molecular weight crystals referred to herein, whether by SEC or IV, was about 3%.

In one aspect, the present invention provides a bicomponent fiber comprising a first poly (trimethylene terephthalate) fiber component and a second poly (trimethylene terephthalate) fiber component, wherein the bicomponent fiber has a molecular weight of> 2.2 Characterized by a molecular weight distribution indicative of an acidity index and an intrinsic viscosity in the range of 0.72 to 0.84 wherein said first fiber component and said second fiber component are disposed relative to each other in a configuration suitable for the occurrence of crimp in said bicomponent fiber .

The molecular weight of the bicomponent fibers herein, indicated by the distribution provided by SEC or indicated by the value of IV, is not precisely predictable by taking into account the molecular weight of the excipient. It is known in the art that the molecular weight of PTT will suffer a thermally induced reduction. The degree of such reduction will depend on, among other factors, the starting molecular weight, the melting temperature, the residence time at that temperature, and the presence of a thermal stabilizer. However, certain features are characteristic of bicomponent fibers.

The bicomponent fibers herein are prepared during a process in which the molecular weight of the two components is different but the analysis by SEC is not so different as to represent the two distinct groups. In the experiments described below , a single molecular weight distribution curve was observed, but the width of the curve was greater than that observed from the single condensation polymer (i.e., the PDI was greater than 2.2).

Likewise, the IV of the feedstock did not completely determine the IV of the irradiated bicomponent fiber. The experiment showed that the IV of the feedstock characterized by an IV of ≤ 0.7 dL / g, under the temperature range of 240 to 250 ° C. according to the process of the present invention, experienced a reduction of less than 4% Because low molecular weight PTT can be processed at very low temperatures.

As a result, the bicomponent fibers herein have one component with a very low IV, which causes the IV of the entire bicomponent fiber to be very low (i.e., in the range of 0.72 to 0.84).

In one embodiment of the bicomponent fibers herein, the first fiber component and the second fiber component are disposed in relation to each other in a parallel configuration within the bicomponent fiber.

In an alternative embodiment, the first fiber component and the second fiber component are disposed relative to each other in an eccentric heartbeat configuration within the bicomponent fiber.

In one embodiment, the bicomponent fiber is a staple fiber. In a further embodiment, the length of the staple fibers is from 1.3 to 15.2 cm (0.5 to 6 inches).

In one embodiment, the bicomponent fibers are crimped.

In one embodiment, the plurality of bicomponent fibers herein are interlaced or entangled in the form of yarns by other methods.

In one embodiment, the bicomponent fibers exhibit orientation. Fiber orientation can be determined by measuring the birefringence of the fiber, a methodology well known in the art. The higher the birefringence of the fiber, the greater the degree of orientation.

In another aspect, the present invention relates to a process for producing a first poly (trimethylene terephthalate) material, characterized by melting a first poly (trimethylene terephthalate) material characterized by an intrinsic viscosity of? 0.7 dL / g to form a first molten stream characterized by a melting temperature below 250 ° C Characterized in that the first molten stream is characterized by a lower intrinsic viscosity of less than 0.03 dL / g less than the intrinsic viscosity of the first material; Characterized in that a second poly (trimethylene terephthalate) material, characterized by an intrinsic viscosity of> 0.7 dL / g, is melted to form a second molten stream, wherein an intrinsic viscosity difference between said first and second molten streams &Gt; 0.1 dL / g; Providing the first and second melt streams to a spinneret to contact the first melt stream with the second melt stream therein; Extruding molten fibers from the spinneret; And forming the solid bicomponent fibers characterized by a first component and a second component disposed relative to each other in a configuration suitable for forming crimps by quenching the molten fibers. .

In one embodiment of the process herein, the first component and the second component are disposed relative to each other in a parallel configuration.

In an alternative embodiment of the process herein, the first component and the second component are disposed relative to each other in an eccentric heartbeat configuration.

In one embodiment of the process herein, the first reagent is characterized by an IV in the range of 0.60 to 0.68.

In one embodiment, the second reagent is characterized by an IV of > 0.8 dL / g. In a further embodiment, the second reagent is characterized by an IV of > 0.9 dL / g.

In one embodiment of the process herein, the first molten stream is at a temperature in the range of 240 to 245 占 폚.

In one embodiment of the process herein, the intrinsic viscosity difference between the first and second melt streams is > 0.2 dL / g.

According to the process of the present invention, a first material, typically a commercially available 0.32 cm (1/8 ") pellet, is characterized by an IV of &lt; 0.7. The lower limit for IV of a suitable first material, The ratio of the two components, the temperature of the low IV component, etc. During the spinning, after processing, or during normal use, when the lower IV component undergoes breakage or cracking, the IV lower limit I crossed.

Suitable poly (trimethylene terephthalate) is available from E.I. children. Is available from DuPont de Nemours &amp; Company under the trade name Sorona (R).

During fiber spinning, the PTT in the melt phase undergoes a high shear force in the spinneret that forms the fibers, leading to further high shear as the fibers are drawn during quenching. In order to enable maintenance of mechanical integrity during these harsh treatments, the polymer should have a sufficiently high molecular weight. For this reason, Chang et al., Op. Cit. ], PTT fibers comprising bicomponent fibers are formed from PTT materials generally characterized by an IV of 0.86 or greater.

It is known in the art that melt processing of PTT can lead to the production of acrolein (C ₃ H ₄ O-prop-2-ene), a toxic by-product. Experiments were performed to determine the effect of processing temperature on the rate of acrolein formation. The results show that during the residence time of 5 minutes, the amount of acrolein produced from the PTT melt increased by a factor of 10 when the temperature was raised from about 240 ° C to about 280 ° C.

In the practice of the process of the present invention it was found that bicomponent fibers having good physical properties could be produced when one of the ingredients was characterized by an IV of &lt; 0.7 dL / g. In addition, a material having a relatively low IV of? 0.7 dL / g is melted and processed at a melting temperature in the range of 240 to 250 占 폚, preferably 240 to 245 占 폚, and 1 It has been confirmed that it is possible to emit smoothly and controllably with four components. Chang et al., Op. cit .], can not be stably radiated into the fiber at temperatures in the range of 240 to 250 ° C.

Chang et al., Op. Cit. ] Is achieved by applying IV to a much higher polymer at 270 [deg.] C (high enough to cause significant polymer degradation at IV) (involving a high incidence of acrolein). The resulting PTT has a very high carboxyl end group for the low IV content of the present invention.

The low melting temperature, which is characteristic of the process herein, offers several benefits, including: a) the IV remains substantially unchanged during the process due to the low temperature, thereby providing improved process control; b) can be induced from a lower molecular weight, with the production of acrolein being greatly reduced for processes requiring IV to be heated to about 270 ° C in order to achieve a sufficiently low IV for the lower component And other improvements in processability.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of an extruder, a pump block, and a radiation block making up a suitable bicomponent fiber emitter extrusion system. The radiator includes two polymer extrusion systems labeled W for the " West "system and E for the" East "system. Geographical notation "East" and "West" are not given meaning. This is a convention that is simply adopted for the distinction between two otherwise almost identical systems. In Figure 1, a Ktron KCLK 720 weight loss feeder (1 W / 1E) was used to melt the polymer pellets into a Werner and Pfleiderer co-rotating 28 mm twin screw extruder (2W / 2E) Supply. The thus formed molten stream is supplied to the pump block 4W / 4E. Each pump block is provided with an associated ballast pump (3W / 3E) and a metering pump (5W / 5E). A ballast pump is used to direct some (or all) molten streams to waste while the remaining molten streams are processed through a metering pump. The ballast pump is a 1.32 cc / rev Zenith gear pump. Each metering pump speed is adjusted to provide a larger or smaller throughput rate. By adjusting the relative pump speed in the east and west extruders, the relative concentration of each polymer component in the radiated fiber can be adjusted. The Westmeter pump (5W) is a 3.30 cc / rev Zenith gear pump. The East meter pump (5E) is a 1.98 cc / rev Zenith gear pump. A single radiation block 9 provided with two spinning streams from each metering pump and provided with a spinning pack consisting of a depression, a cyclic two-component filtration pack 10 and a spinnerette 11, Converge to the inside. In the following example, the filter pack 10 consisted of one 50 mesh filter screen, three 200 mesh filter screens, and about 20 milliliters of a 10/25 glass chip. The two-component merging-post spinneret 11 of 7.9 cm (3.12 inches) diameter included 34 pairs of holes (not shown) arranged in two circular arrays. Each hole was 0.63 mm in diameter x 4.24 mm in length. The thermocouple (7W / 7E) located at the exit of the extruder was used to determine the melt stream temperature in the examples. The pack pressure can be controlled by optimizing the temperature of the molten stream in the pump block (6W / 6E) and the radiation block.

Figure 2 illustrates a cross flow melt-spinning device suitable for use in the process of the present invention. The quenching gas 21 passes through the hinge baffle 28 and through the screen 25 through the plenum 24 into the zone 22 below the spinneret surface 11 to cause the still- Resulting in a substantially laminar gas flow across the drawn fibers 26. The baffle 28 has a hinge on its top so that its position can be adjusted to change the flow of the quenching gas across the zone 22. The spinneret surface 11 is recessed by a distance A above the top of the zone 22 so that the quenching gas is not contacted until after a predetermined delay to the fibers that have just been spun while the fibers are heated by the sides of the depressions . In the following example, the so quenched fiber was transferred from the spinneret through the baffle 27 to a roll array on the lower floor (see FIG. 3). The finish is now applied to the solid fibers by contacting them with the finish roll 210.

3, the fibers 26 are routed from the finish rolls around the drive rolls 31, around the idler rolls 32, and then back around the heated rolls 33. The temperature of the roll 33 may range from about 50 캜 to about 70 캜. The fibers are then conveyed to a heated draw roll 34. The temperature of the roll 34 may range from about 50 캜 to about 170 캜, preferably from about 100 캜 to about 120 캜. The fibers are then transferred from the rolls 34 to a heated roll 35 and after any unheated rolls 36 (which adjust the yarn tension for satisfactory winding) windup (37). The draw ratio (the speed of (34) divided by the speed of (33)) ranges from about 1.4 to about 4.5, preferably from about 3.0 to about 4.0. It is not necessary to apply significant tension between pairs of rolls 33 or between pairs of rolls 34 (beyond what is needed to hold the fibers on the roll). In addition, heat treatment can be performed using a heating chamber such as one or more other heated rolls, steam jet, or "hot chest ". The heat-treatment is carried out by a roll 35 of FIG. 3, which heats the fibers at a substantially constant length, for example, at a temperature in the range of from about 110 DEG C to about 170 DEG C, preferably from about 120 DEG C to about 160 DEG C .

The duration of the heat-treatment depends on the yarn denier; It is important that the fiber can reach a temperature substantially equal to the temperature of the roll. If the heat-treating temperature is too low, the crimp may decrease under tension at high temperatures and shrinkage may increase. If the heat-treatment temperature is too high, the operability of the process becomes difficult due to frequent fiber breaks. It is desirable to avoid the loss of fiber crimp by maintaining the fiber tensions substantially constant at this point during the process, so that the speeds of the heat-treating rolls and pulling rolls are substantially the same.

Alternatively, the feed roll may not be heated and the draw can be performed by a draw-jet and a heated draw roll (which also heat-treats the fibers).

Optionally an interlaced jet can be placed between the draw / heat-process roll and the take-up part.

Finally, the fibers are wound. A typical winding speed in the production of the inventive product is about 2,500 meters per minute (mpm). The range of usable winding speed is about 2,000 mpm to 6,000 mpm.

Example

Test Methods

Measurement of crimp contraction

Each fiber was formed with about 5000 +/- 5 total denier (5550 dtex) of tufts with tareles at a tension of about 0.1 gpd (0.09 dN / tex). The tresses were then folded in two to halve the length of the tresses to accommodate the interior of the oven used for heatsetting. Folded tufts were hooked in their mid-section and conditioned for at least 16 hours at 21 +/- 1 DEG C (70 +/- 1 DEG F) and 65 +/- 2% relative humidity. Subsequently, the folded tuft was hooked substantially perpendicularly on the rack from the hook in its mid-section and the weight of 1.5 mg / den (1.35 mg / dtex) was applied to the bottom of the tuft through two loops of folded tufts. The weighed tufts were then heated in an oven for 5 minutes to 121 DEG C (250 DEG F), then the racks and tufts were collected and allowed to cool for 5 minutes and then weighed 1.5 mg / den for the remainder of the test And conditioned for at least 2 hours at 21 +/- 1 DEG C (70 DEG F +/- 1 DEG F) and 65% +/- 2% relative humidity. The length of the tufts was measured to within 1 mm and recorded as "Ca". Then, a weight of 1000 grams was placed on the bottom of the tufts, allowed to reach equilibrium, and the length of the tufts was measured within 1 mm and recorded as "La ". The crimp contraction "CCa" value (%) was calculated according to the following equation:

CCa = 100x (La-Ca) / La

Determination of IV

The intrinsic viscosity (IV) was determined using the Goodyear R-103b method.

Determination of molecular weight distribution

The molecular weight distribution was determined by employing size exclusion chromatography (SEC), a technique well known in the art, for use in determining the molecular weight distribution. The polydispersity index (PDI) was determined as PDI = M _w / M _n , where M _w is the weight average molecular weight and M _n is the number average molecular weight (determined from SEC).

Textile Manufacturing

Three grades of Sorona (R) poly (trimethylene terephthalate) resin pellets were obtained from Wilmington, Del. children. Was obtained from E.I DuPont de Nemours and Company. The first grade was characterized by an IV of 1.02 dL / g, the second with an IV of 0.96 dL / g, and the third with an IV of 0.66 dL / g. In preparation for melt spinning, each grade was dried in a vacuum oven under nitrogen at 84.6 ㎪ (25 inch mercury) vacuum and at a temperature of 120 캜 for 15 hours. The so-dried resin pellets were transferred directly to the nitrogen-purged feed hopper (Figure 1) of the spinner.

The melt-spun bicomponent filaments were air-quenched. 1, quenching air 1 was supplied at room temperature and impinged on a thread line 6 extruded at 0.12 m / sec as measured at 0.61 meters below the spinneret.

Comparative Example A

After drying the 1.02 IV cattle or (R) pellets were added to an extruder of both described above. Both extruders were set the same and the heating profiles in the nine zones were 180/240/250/250/255/255/250/255/255 ° C. The temperature of the melt stream measured at the outlet of the extruder was 256 占 폚.

The speed of both the east and west metering pumps (5W5E in Fig. 1) was set at 14.4 g / min. The speed of both ballast pumps was set at 6.6 g / min. Referring to Fig. 3, the yarn was wound six times around an unheated supply roll / separator roll 31/32 operated at a linear speed of 796 m / min. Thereafter, the yarn was wound around the 65 ° C drawing roll 33 which was also operated at a linear speed of 796 m / min 5 times. Then, the yarn was wound around the heat treatment roll 34 operated at a linear velocity of 150 DEG C and 2550 m / min 9 times. Then, the yarn was wound 9 times around an unheated letdown roll 35 operated at a linear speed of 2550 m / min. Subsequently, the yarn was wound six times around an additional set of unheated letdown rolls 36 operated at a linear speed of 2550 m / min. Yarn was collected on a cardboard tube at a linear velocity of 2480 m / min at a Barmag SW6 2s 600 spindle (Barmag AG, Germany).

Table 1 shows the results for the fibers prepared in Comparative Example A (CE A) using the method described in the fiber making section. The properties of the fibers made from two identical molten streams are shown in Table 1. The properties of the fibers (CE A-1) formed from a single melt stream, run at the same rate as described for one component of the two component fibers, are also shown in Table 1. The term " n / a "means" not applicable ".

Both IV and molecular weight distributions were determined for the fibers in question so emitted. Crimp contraction, and CCa were also measured. A very low CCa value was obtained for this comparative example.

Examples 1 to 3

As in CE A, a 1.02 IV Sorona (TM) resin pellet was fed back to the West extruder. However, 0.66 IV SORONA resin pellets were supplied to the yeast extruder. The temperature profiles of the nine heating zones of the extruder were set at 140/200/235/245/245/245/245/245/245 ° C. The temperature of the melt stream measured at the outlet of the extruder was 245 ° C.

A 3.0 draw ratio item was run using a feed roll and a draw roll rotating at 850 m / min. The 3.2 draw ratio items were collected using feed rolls and pull rolls rotating at 796 m / min. A 3.4 draw ratio item was collected using a feed roll and a draw roll rotating at 750 m / min. All other roll speeds and temperatures were kept the same as in Comparative Example 1.

The results for the fibers prepared in Examples 1 to 3 are shown in Table 2.

The properties of the fibers (Ex 1-1 and Ex 1-2) formed separately from each melt stream, run at the same rate as described for each component of the two component fibers, are also shown in Table 2. The extrudates so produced were co-dissolved in trichloroethane and analyzed by SEC.

Example 4

The conditions of Example 3 were repeated except that the extruder profiles were 180/255/255/255/255/255/255/255/255/255 ° C, . The previous line temperature for the melt stream from the West extruder was 256 占 폚.

The properties of the fibers separately formed from each melt stream (Ex 4-1 and Ex 4-2), performed at the same rate as described for each component of the two component fibers, are also shown in Table 3. The extrudates so produced were co-dissolved in trichloroethane and analyzed by SEC.

The results for the fibers prepared in Example 4 are shown in Table 3.

Examples 5 to 7

As shown in Table 4, Example 1 was reproduced, except that the pumping speed of the metering pump was changed. The results for the fibers prepared in Examples 5 to 7 are shown in Table 4.

Claims (12)

(Trimethylene terephthalate) material characterized by an intrinsic viscosity of &lt; = 0.7 dL / g to form a first molten stream characterized by a melting temperature below 250 DEG C, said first molten stream comprising Characterized by a lower intrinsic viscosity of 0.03 dL / g or less than the intrinsic viscosity of the first material; Characterized in that a second poly (trimethylene terephthalate) material, characterized by an intrinsic viscosity of> 0.7 dL / g, is melted to form a second molten stream, wherein the difference between intrinsic viscosities of the first and second molten streams &Gt; 0.1 dL / g; Providing the first and second melt streams to a spinneret to contact the first melt stream with the second melt stream therein; Extruding molten fibers from the spinneret; And a step of quenching said molten fibers to form solid bicomponent fibers characterized by a first component and a second component arranged relative to each other in a configuration suitable for the formation of a crimp, . The process of claim 1, wherein the first fiber component and the second fiber component are disposed in a bicomponent fiber in a side by side configuration with respect to each other. The process according to claim 1, wherein the first fiber component and the second fiber component are disposed about each other in an eccentric sheath / core configuration within the bicomponent fiber. The process according to claim 1, wherein the first material is characterized by an IV in the range of 0.60 to 0.68. The process according to claim 1, wherein the second material is characterized by an IV of > 0.8 dL / g. 6. The process of claim 5, wherein the second material is characterized by an IV of > 0.9 dL / g. The process of claim 1 wherein the first molten stream is at a temperature in the range of from 240 to 245 ° C. The process of claim 1, wherein the difference between intrinsic viscosity of the first and second melt streams is > 0.2 dL / g. 3. The composition of claim 1, wherein the first material is characterized by an intrinsic viscosity in the range of 0.60 to 0.68 dL / g, the second material is characterized by an intrinsic viscosity of > 0.8 dL / g, The difference between the intrinsic viscosity of the stream is > 0.2 dL / g. 10. The process of claim 9, wherein the first molten stream is at a temperature in the range of from 240 to 245 占 폚. 11. The process according to claim 10, wherein the second material is characterized by an intrinsic viscosity of > 0.9 dL / g. The process according to claim 1, further comprising the step of applying a high temperature to bicomponent fibers to generate crimps therein.

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