ES2230684T3 - STRETCHING OF POLYESTER FILAMENTS. - Google Patents

Abstract

A method for simultaneously stretching a mixture of polyester filaments in the same polyester filament bundle, wherein said mixture is a mixture of filaments of different cross sections, the mixture having polyester filaments including cross sections selected from at least two of the following types of cross sections: serrated oval; trilobular; shaped tape; solid; hollow with multiple cavities; and round, and wherein said polyester is branched chain with between 0.1 and 0.8% molar chain branching.

Description

Stretched polyester filaments.

Field of the Invention

This invention relates to the improved stretching of polyester filaments and, more particularly, to a process for stretching polyester filaments mixed in it beam, especially the stretching of a beam of said filaments mixed, and the resulting stretched beams and filaments and subsequent procedures for these and their products.

Background of the invention

Polyesters have been produced commercially at large scale for processing in shaped items such as fibers, mainly from poly (terephthalate of ethylene). Synthetic polyester threads have been known and have been used commercially for several decades, having been suggested firstly by W. H. Carothers, U.S. Patent No. 2,071,251, and then Whinfield and Dickson suggested poly (terephthalate ethylene) in U.S. Patent No. 2,465,319.

Although many polymers of polyester (including copolymers), the most widely polyester manufactured and used so far for textile fibers has been poly (ethylene terephthalate), which is often referred to as PET homopolymer. PET homopolymer has generally been preferred over other copolymers due to its lower cost, and also because its properties have been completely adequate, or even preferred, for most end uses. You know, without However, the PET homopolymer requires conditions of special dyeing (high temperature that requires pressure supraatmospheric) not required for nylon fibers, for example, so they have been suggested and used commercially copolyesters for various purposes. The PET homopolymer is called often 2G-T, while poly (terephthalate of trimethylene) is called 3G-T (although some have started calling it PTT), and poly (terephthalate from tetramethylene) is called 4G-T, and so successively. Some interest has been shown towards 3G-T, and also towards 4G-T, but 2G-T is the most used polyester polymer up to the moment, so it is mainly discussed below in the present document, but it will be understood that the invention also applies to other polyesters, for example others C 2 -C 4 alkylene terephthalates, such as 3G-T and 4G-T mentioned above, and copolyesters.

Polyester fibers are (1) filaments continuous or (2) fibers that are discontinuous, these being called last often cut fibers, and are manufactured when formed in first place by extrusion in polyester filaments continuous, which are processed in the form of a bundle of filaments of Continuous polyester before becoming cut fibers. A important stage in the processing of such filaments of Continuous polyester has been the "stretched" to increase the orientation of long chain polyester molecules, and thus improving the properties of the filaments. The The present invention relates to improvements in this stage of stretching and to the improved products that result from it.

Mainly, the objective of the producers of synthetic fiber has been repeating the advantageous properties of natural fibers, the most common of which have been the fibers of cotton and wool.

Most polyester cut fiber has It has a round cross section and has been mixed with cotton. Recently, however, United States Patents No. 5,591,523 (DP-6255) and 5,626,961 (DP-6365-A) and the pending application No. 8 / 662,804 (DP-6400) filed on June 12, 1996, and now allowed, which correspond respectively to WO 97/02372, WO 97/02373 and WO 97/02374, whose descriptions are incorporated herein as a reference, they have revealed inventions that refer to beams of polyester that are suitable for conversion into wicks in a combed or wool system and further processing in such systems, finally in textile materials and clothing. The This invention has been made in the direction of that work, of mode described in particular reference to its value in the stretched polyester filaments in beams for processing additional in such systems, but is not reduced to the stretching of such beams and is believed to have the potential to be used more widely when other bundles of filaments are stretched polyester.

As has been disclosed, for example, in the U.S. Patent No. 5,591,523 (DP-6255), sometimes it has been desired to obtain different denier filaments by filament (dpf), so it was surprising what was expressed in the example 1 of that patent: it was possible to spin polyester filaments unstretched that had been denier yarn significantly different on the same spinning machine without adjusting the rate of natural stretch and then subsequently stretch a mixture internal of these filaments spun simultaneously in the same beam at the same natural stretch rate to provide filaments with excellent properties that were different due to their different dpfs (col. 6, lines 15-29). The The present invention extends this surprising discovery and what simultaneously extends other beams mixed filaments beyond the bundles of mixed filaments specified in that patent.

Summary of the Invention

According to one aspect of the invention, it is provided a procedure to simultaneously stretch a mixture of polyester filaments in the same polyester filament bundle, wherein said mixture is a mixture of section filaments different cross-sections, including mixing filaments of polyester that have cross sections selected from at minus two of the following types of cross sections: oval toothed trilobular; loop-shaped; solid; hollow with multiple cavities; and round, and in which said polyester is of branched chain with between 0.1 and 0.8% molar of branching chain. Molar% is conventionally calculated as weight molecular chain branching unit divided by weight molecular of the polymer repeat unit per 100, being The repeating unit for 2G-T terephthalate ethylene by way of example.

According to another aspect of the invention, provides a mixture of polyester filaments, wherein said mixture is a mixture of filaments of cross sections different, including mixing polyester filaments that have selected cross sections of at least two of the following types of cross sections: serrated oval; trilobular; shaped tape; solid; hollow with multiple cavities; and round, and in which said polyester is chain branched with between 0.1 and 0.8% molar of chain branching, and in which the contraction per test is between 0.5 and 3%. Such mixtures may be in the form of stretched threads and stretched beams of continuous filaments, and subsequent products of mixtures of polyester filaments that result from these, including mixtures of fiber cut in various forms, including threads, and materials textiles and clothing as well as the threads themselves, and they understand that the resulting mixtures of polyester fibers they can also be mixed with other fibers, such as other polymers synthetics, including polyamides (nylon of various types) and polyolefins, for example, and / or natural fibers, such as cotton and wool.

According to another aspect of the invention, provides a mixture of polyester filaments, obtainable by simultaneously stretch a mixture of polyester filaments in the same beam of polyester filaments, wherein said mixture is a mixture of filaments of different cross sections, including mixing polyester filaments that have sections cross-sections selected from at least two of the following types of cross sections: serrated oval; trilobular; shaped like headband; solid; hollow with multiple cavities; and round, and in the that said polyester is branched chain with between 0.1 and 0.8% chain branching molar, and in which the contraction by It is between 0.5 and 3%.

The terms "filament" and "fiber" are used in this document, and generally are not intended to be mutually exclusive; sometimes, however, these terms general are modified, as in terms like "filament continuous "and" cut fiber ".

Significantly, as will be explained in relation with stress strain curves in the Examples, I don't know found no natural stretch rate when stretched simultaneously according to the invention. In addition, it was not experienced no neck stretch compared to our experience when homopolymer filaments are stretched 2G-T.

Brief description of the drawings

Figure 1 is an enlarged photograph of cross sections of mixed filaments according to the invention as explained below in this document in greater detail.

Figures 2 to 6 are deformation curves by Average tension of single filaments for use in mixtures according to invention, as described more specifically below in the present document.

Detailed description

It would be redundant to repeat what has already been disclosed in the art. As indicated, the preparation of polyester polymers and the spinning of filaments from them has been disclosed in the art. The stretching of polyester filaments has also been revealed in many backgrounds that originate in those of Marshall and Thompson in Nature, Vol. 171 (January 3, 1953), pages 38-39, " Drawing Synthetic Fibers ", in J. Applied Chem., 4 (April 1954), pages 145-153 " The Drawing of Terylene ", and in Proc. Roy Soc. (London), Vol. A221, pages 541-557, " The Cold Drawing of High Polymers ". As indicated hereinabove, the present invention was made during the work in the drawing of polyester filaments in bundles that were being developed for combing and processing wool, so that much of the detailed description herein refers to said filaments and beams, but the inventive concept has a wider application.

As indicated, the essence of the invention is the use of branched chain polyester polymer to manufacture polyester filaments that stretch according to the procedure of the invention to provide filament mixtures according to the invention. The use of chain ramifiers (ie intermediate multifunctional polyester trainers that have more than two required functional groups that are required for the polymerization, such as a glycol and a dibasic acid, both being difunctional) has been disclosed in the art as MacLean et al., United States Patents Nos. 4,092,229 and 4,113,704, Mead et al. in U.S. Patent No. 3,335,211, Oxford et al., WO 92 / 13,120, Duncan, U. S. SIR document H1275, DuPont (Broaddus et al.) EPA2 294.912, Reese, US Patents United Nos. 4,833,032, 4,966,740 and 5,034,174, Goodley et al. in the U.S. Patent No. 4,945,151, and referred technique and cited in said specification, such as Vaginay, Patent of United States No. 3,576,773. Some of this background used different terminology, as viscosity additives, because the materials were added to improve spinning capacity, or by other reasons. Much of this prior art referred to spinning High speed continuous filament threads such as threads feed for stretch-texturing, so that those continuous filaments were oriented for spinning, in place of amorphous, such as those that are more suitable for stretching in the form of a beam for conversion into cut fiber, which is preference and special interest according to the present invention. Low contraction of filament mixtures according to the invention distinguish our stretched filaments from the filaments of major shrinkage manufactured by high speed spinning to make yarn-oriented filaments for use as threads feed for stretch-texturing, often referred to as POY. The contraction is the contraction by referred to at the bottom of the Col 6 of Knox United States Patent No. 4,156,071, and it is measured in the manner described there by Knox.

As indicated, U.S. Patent No. 5,591,523 and WO 97/02372 have already disclosed in Example I simultaneous stretching of a dpf polyester filament beam mixed and it was surprising that this could be achieved to provide stretched filaments that were satisfactory and without dark coloring defects. Said procedure and the filaments stretched resulting from mixed dpf, all cross section Serrated oval, have already been disclosed in this specification. In addition, U.S. Patent No. 5,629,961 and the document WO 97/02373 have disclosed filaments of oval cross section improved toothed with 6 slots, and have incorporated the disclosure of United States Patent No. 5,591,523, as did the WO 97/02374 and allowed the United States request no. 08 / 662,804. It follows that this application has to do particularly with additional aspects of the concept of invention that are not covered in these previous patents and patent applications. These additional aspects are mentioned now; particularly, mixtures of section filaments different cross-sections that are not completely sectional serrated oval transverse, such as a cross section that is round while the other cross section is not round, by trilobular example, tape-shaped or even serrated oval; mixtures of more than one different non-round cross section, like any mixture of said cross sections not round; mixtures of solid filaments and filaments with one or more longitudinal cavities, often referred to as a cavities as a hollow filament, but also as filaments with multiple cavities with, for example, 3 or 4 cavities, or with 7 cavities, such as it is disclosed, for example, in US Pat. Nos. 3,745,061, 3,772,137 and 5,104,725, and technique to which it is done reference and is cited in said descriptive reports; as long as refers to the terminology in this document, said filaments with longitudinal cavities are included herein document within the concept of "non-round" filaments given that their previous behavior during stretching (when they were made of 2G-T homopolymer without branching string) has differed from the behavior of round filaments (solids) (similarly made without chain branching); also mixtures of dpfs filaments that differ, even when they are of the same cross section (not all of section serrated oval transverse as mentioned earlier in the this document), but also of a different cross section and of different dpf; said dpf differences may be such that a major dpf is at least 1.1X a minor dpf, or major differences, as at least 1.2X, 1.3X or 1.5X or more.

As will be seen in the examples later in the In this document, it is difficult to predict dpfs and properties of the stretched filaments that are obtained by stretching mixtures of filaments according to the invention.

The invention is further illustrated in the following examples, which, for convenience, refer to combed system processing, as explained above in the present document. All parts and percentages are in weight unless otherwise indicated. Contractions for The products for all the examples were in the range between 1% and 1.5%.

Most test procedures are well known and / or described in the art. To avoid doubts, the following explanation of the procedures is provided that They were used in the following paragraphs.

Instron The mean strain deformation curves were obtained in the following manner as an average of 10 individual filaments of each type taken from the beam. Ten samples of each type of filament were separated from the beam using a magnifying lens (LUXO Illuminated Amplifier). The denier per filament (DPF) of each filament sample was measured in a VIBROSCOPE (Audio Oscillator Model 210C HP). The sample filaments were mounted one at a time on an INSTRON (Model 1122 or 1123) and the strain deformation behavior was measured. Ten ruptures were recorded for each type of filament, and the average of the 10 samples for each type of filament was recorded so that, as will be readily understood, the value readings of a strain strain curve of an individual filament are not they necessarily correlate with the tensile properties calculated and presented on average in the Tables.

Units . The measurements were made using conventional textile units from the United States, including denier, which is a metric unit. To comply with the mandatory practices at another site, the dtex and CPcm equivalents of the DPF and CPI measures are given in parentheses after the current measures. For tensile measurements (MOD, for initial modules, and TEN, for toughness), however, current measurements in gpd have become g / dtex and the latter have been given in the Tables, while deformation curves by tension in the Figures show the original metric tensile values on the Y axis.

Curl frequency was measured as the number of folds per inch (CPI) after beam curling. Curly is shown by several peaks and valleys in the fiber. Ten filaments were removed from the beam at random and placed (one at a time) in a relaxed state in fastening systems of a device that measures the length of the fiber. The fastening systems are operated manually and initially moved together close enough to prevent stretching of the fiber while being placed in the restraint system. One end of a fiber is placed in the left holding system and the other end in the right holding system of the measuring device. The left fastening system is rotated to eliminate any rotation in the fiber. The support of the right fastening system moves slowly and carefully to the right (extending the fiber) until the shallow part of the fiber has been removed but without removing any folds. Using an illuminated amplifier, the number of peaks on the upper and lower side of the fiber is counted. The support of the right fastening system then moves slowly and carefully to the right until all the curling has disappeared. Care is taken not to stretch the fiber. This fiber length is recorded. The curling frequency for each filament is calculated as:

\ frac {\ text {Total number of spikes}} {\ text {2 x Filament Length (without crimp)}}

The average of the 10 measures of all 10 fibers is registered for the CPI (folds per inch), being the CPcm metric equivalent.

CTU (Curl Degree) was also measured in the beam and is a measure of the length of the extended beam, to eliminate the curl, divided by the non-extended length (i.e., curly), expressed as a percentage, as described in Anderson et al., U.S. Patent No. 5,219,582.

Values for non-round fiber cross sections were obtained by using the following procedure. A fiber specimen is mounted on a Hardy microtome (Hardy, United States Department of Agriculture around 378, 1993) and divided into thin sections according to procedures as essentially disclosed in "Fiber Microscopy Its Technique and Applications" by JL Sloves ( van Nostrand Co., Inc., New York 1958, No. 180-182). The thin sections are then mounted on a stage of super FIBERQUANT microscope video system (Vashaw Scientific Co., 3597 Parkway Lane, Suite 100, Norcross, Georgia 30092) and displayed on the Super FIBERQUANT CRT with magnifications as necessary. The image of a thin individual section of a fiber is selected and the dimensions of the critical fibers are measured. The relationships are then calculated. This procedure is repeated for each filament in the field of view to generate a set of statistically significant samples, and the averages are provided herein. Aspect ratios and modification ratios for non-round cross sections are provided in Tables in parentheses following the indication of the type of cross section, for example, "OD (1.37)" indicates a serrated oval cross section of relationship 1.37 aspect. Similarly, the hollow contents are given in parentheses after the indication of a hollow cross-section, for example, a 7% hollow content is shown as "Hollow (7%)", measured as described by Aneja et al in the US Pat. United No. 5,532,060.

Relative viscosity (VRL) is the viscosity of the polymer dissolved in HFIP solvent (hexafluoro-isopropanol) containing 100 ppm of 98% reactive sulfuric acid. The viscosity measuring device is a capillary viscometer obtainable from several commercial vendors (Design Scientific, Cannon, etc.). The relative viscosity in square meters per second is measured in a 4.75% by weight solution of polymer in the solvent at 25 ° C. The H 2 SO 4 used to measure VRL destroys crosslinks, specifically silicon in the case of tetraethyl ortho silicate chain branching.

Non-acid relative viscosity (NRV) is the viscosity of polymer dissolved in a similar way, measured and compared in hexafluoro-isopropanol solvent but without any sulfuric acid. Since no acid is present, the crosslinks are left intact when the NRV is measured.

Delta VR (ΔVR) is the expression we have used herein to define the difference between NRV and LRV measured as defined above, and expresses the amount of crosslinking destroyed by the acid when LRV is measured.

Product defects are classified in this document into three categories:

1) Defects of the equivalent textile material (DMTE),

2) Dark dye defects (DCO),

3) Splinters (AST).

The first two defects (DMTE and DCO) are fibers and fiber agglomerations that are dyed darker than fibers normal. DCOs have a diameter less than 4X the fiber diameter (stretched) normal. DMTEs have a diameter 4X the fiber diameter normal or higher Both defects must be greater than 0.25 inches (6.35 mm). Samples were processed through a card Top type rollers. The wick is dyed light blue and visually examine on an illuminated magnifying glass. Fibers that are stained darker than the bulk of the sample is removed, it They are classified as DMTEs or DCOs and are counted. Each type of defect is presented as a number of defects per 0.1 pounds (0.045 kg) of wick. Splinters are agglomerations of fibers or fibers too big. To be classified as a splinter, this defect also must be greater than 0.25 inches (6.35 mm) but its total diameter must be greater than 0.0025 inches (0.0635 mm). The splinters are concentrate on the residue of flat strips when a sample cut It is processed through a flat card. The residue of flat strips It is visually examined against a black background. The splinters are they withdraw, they are classified by size, they are counted, and they are expressed in A sample weight basis.

Example 1

The mixed filaments were melt spun to 282 ° C from chain ethylene terephthalate polymer branched, said filaments being mixed a mixture of light filaments (thinner denier) of oval cross section Toothed (OD) and heavy filament (heavier denier) section round cross. The different filaments were cast spun simultaneously through different capillaries in it row, each containing 1000 capillaries, from polymer containing 0.24% (0.22% mole) of tetraethyl silicate (STE, essentially as described in Mead et al., US Pat. United No. 3,335,211) and having 10.2 · 10-6 of VRL and 15.3 · 10-6 of VNR (therefore 5.1 · 10-6 ΔVR), at a total of 23.68 lbs / h (10.75 kg / h) speed for each row, and spinning in bobbins at 1800 ypm (1650 m / min). The rows had 516 round capillaries, each of a flow area of 0.0003079 square inches (0.199 mm2) to make heavy filaments (round cross section), and 484 capillaries not round each of a flow area of 0.0002224 inches square (0.143 mm2), to make light filaments (section serrated oval transverse). The smallest non-round capillaries they were placed in the five inner rings (of 9) while the larger round capillaries were placed in the four rings outside of the row. The shape of the hole for the capillaries serrated oval was essentially as described in the application of United States No. 08 / 662.804 (DP-6400) and WO 97/02374 referred to above herein document. Molten filamentous currents were inactivated using radially directed air from an inactivating system profiling, as described in Anderson, et al., US Pat. United No. 5,219,582. The resulting filament beam it consisted of a mixture of different cross sections and of minor and major denier filaments with properties indicated in the Table 1A Strain strain deformation curves unique of the two different types of filaments are shown in the Figure 2, the continuous curve being for a smaller filament denier (light) of toothed oval cross section (OD), and being the dashed curve for a larger denier round filament (heavy).

TABLE 1

Filament Kind Shape DPF Mod Have % E_ {B} Light OD (1.37) 1.6 (1.8) 12.2 0.7 170 Heavy Round 2.7 (3.0) 13.8 0.7 131

Sixty-eight coils of the mixed filaments finished spinning to form a beam with a Nominal mixing ratio of 40% serrated oval, lower dpf, and 60% round filaments, of greater dpf. This beam was stretched to a 2.22X stretch rate while spraying with water at 95 ° C. The beam was then passed through a box inverter filler and subsequently relaxed at 145 ° C to provide a final beam size of approximately 74,800 denier (83,100 dtex) of a thorough mixture of curly filaments (10.6 CPI, 4.2 CPcm) of both types of filaments whose properties are presented in the Table IB.

TABLE IB

Shape Mixture DPF Mod Have % E_ {B} lightweight dpf OD (1.24) 40 0.98 (1,1) 28.7 1.1 9 heavy dpf Round 60 1.19 (1,3) 32.0 1.7 12

A conventional finish was applied to provide a level of finish (in fiber) of 0.15%. Denier nominal per filament (i.e. the denier of the total divided beam by the number of filaments) it was 1.1 dpf (1.3 dtex), being approximately 40% of the filaments of oval serrated form (0.98 denier) and the rest 60% round (1.19 denier).

The product was processed and then scrutinized to see Product Defects, DMTE, DCO and AST, all of which recorded zero defects, so it is clear that the quality of the product was not adversely affected by stretching simultaneous of a mixture of different forms and deniers of finished spinning filaments, which was surprising and the opposite of the previous experience in attempts to process filaments mixed and mixed denier made essentially similar to from homopolymers without chain branching, as will describe now.

Comparisons

By comparison, when four mixtures of different filaments of 2G-T homopolymer without no chain branches were stretched similarly in the same beams, significant Product Defects were noticed when the stretched beams were processed and scrutinized, as indicated in Table C2. Stretch rates are indicated as "TE" in Table C2. Each mixture that was stretched together it was a mixture of two types of filaments between four types CA, CB, CC, and CD, whose properties are shown in Table C1. The filaments were spun separately from the homopolymer 2G-T without any chain branching (VRL 20.4 ? 10-6), but otherwise they are essentially as describe for Example 1.

TABLE C1

one

TABLE C2

2

Significant numbers of Defects of Product resulting from stretching said mixed filaments of homopolymer (being CA / CB mixtures of filaments of different deniers, but both oval cross-section toothed relationship of modification 1.7, and CC / CD being mixtures of filaments thereof denier, but being one round and the other cross section serrated oval modification ratio 1.7) contrast with zero of Product Defects obtained from Example 1 and from of other Examples, according to the invention. Deformation curves by tension of unique filaments of these four types of homopolymer, CA, CB, CC and CD, are shown in Figure 3, and are they can contrast with the curves in Figure 2 and in the Figures 4-6 for chain polymer filaments branched. Those in Figure 3 have all flat parts significant that indicate a natural stretch rate for these homopolymer filaments, as is well known. Your rates of Natural stretching are presented as "TDEN" in the Table C1. As can be seen, the natural stretching rates for CC and CD are both 1.9X, that is, both are equal, but the Simultaneous stretching of DC and CD mixtures gave numbers Significant Dark Dye Defects. The curves in the Figure 2 does not show corresponding flat parts; This can explain, in retrospect, why these filaments can be stretch together and provide products without defects Product, as opposed to unsatisfactory experience previous in simultaneous stretching of most sections transversal and / or mixed deniers (because the filaments were of the homopolymer).

Example 2

A mixture of three types of filaments, which have different cross sections but all 7.6 dpf (8.4 dtex), by spinning each type separately to 282 ° C from polyester containing 0.27% STE, 8.9 · 10-6 VRL and 15.4 · 10-6 VRN (6.5 · 10-6 ΔVR), at 1600 ypm (1460 m / min), but being otherwise as described for Example 1, to provide filaments spinning finishes whose properties are provided in Table 2A. The round filaments were extruded at a speed of 85.2 lbs / h (38.7 kg / h) from a row of 520 capillaries. Filaments gaps were extruded at a speed of 80.4 lbs / h (36.5 kg / h) at from a row of 490 capillaries, using a hole shape essentially as described in Figure 5B of the Patent of United States No. 5,356,582. The serrated oval filaments are extruded at a speed of 73.8 lbs / h (33.5 kg / h) from a row of 450 capillaries. The strain deformation curves of Unique filaments of each type are shown in Figure 4, together with a 2C curve which is a strain strain curve for a 6-slot filament described in Example 3 a continued in this document.

TABLE 2A

3

Eleven filament reels were combined round, 11 reels of the hollow filaments and 12 coils of the serrated oval filaments to form a beam that has a Nominal mixing ratio of 34% round filaments, 33% hollow, and 33% serrated oval with a total of yarn denier in total beam of 125,476 (139,418 dtex). This beam was stretched, curled and essentially relaxed as described for Example 1, but at a 3.0X stretch rate to provide a stretched beam of approximately 47,000 denier (52,000 dtex) of a thorough mixture which contains these three curly shaped filaments different (8.4 CPI, 3.3 CPcm, 16.7 CTU) with a nominal dpf of approximately 2.85 (3.2 dtex) whose filament properties are presented in Tala 2B.

TABLE 2B

4

A conventional finish was applied as in the Example 1, and the beam was processed and scrutinized to see Defects of Product. It was surprising, given the previous attempts with conventional filaments, which the resulting wick of this Example of a thorough mix of three different cross sections (round, hollow, and serrated oval), showed no Defect of Product of DMTE, DCO, and AST, despite having been stretched simultaneously.

The perception of a textile material by A consumer can be critical for its commercial viability. The aesthetics of a textile material can be significantly affected by the use of fiber blends of different sections transversal. But previously it has not been possible to stretch simultaneously such mixtures of filaments from conventional homopolymers.

Example 3

In Tables 3A and 3B, the data is summarized for finished filaments of spinning and in a stretched beam of three filaments with different form (same dpf) that were prepared and processed essentially as described in Example 2, but in which the 2C serrated oval shape that has only 4 slots was replaced by 3C filaments having a cross section of 6 slots, according to It is described in US Patent No. 5,626,961 (DP-6365-A). As explained in the Example 2, a stress strain curve has been included for said 6-slot cross section filament in Figure 4 as curve 3C, the filaments being finished spinning round and gaps essentially the same for both Examples 2 and 3.

TABLE 3A

5

TABLE 3B

6

The stretched beam (8.3 CPI, 3.3 CPcm, 19.9 CTU) of 2.85 nominal dpf (3.2 dtex) was processed and showed zero Defects of Product (DMTE, DCO, AST).

Example 4

In Tables 4A and 4B, the data is summarized similarly for filaments in four different ways that prepared essentially as described in Example 2. The Round filaments were extruded at a speed of 70.4 lbs / h (32 kg / h) from a row of 286 capillaries; the filaments trilobular extruded at a speed of 44 lbs / h (20 kg / h) at from a row of 160 capillaries, using a hole shape essentially as described in Figure XI of the Patent of United States No. 2,945,739; serrated oval filaments (4 grooves) were extruded at a speed of 110 lbs / h (50 kg / h) at from a row of 450 capillaries and the hollow filaments are extruded at a speed of 89.4 lbs / h (40.6 kg / h) from a row of 363 capillaries. Strain deformation curves of unique filaments of these different cross sections are shown in Figure 5.

TABLE 4A

7

TABLE 4B

8

Twenty filament coils were combined round (66,924 denier, 74,360 dtex), thirty-five coils of trilobular filaments (64,400 denier, 71,555 dtex), four serrated oval filament coils (20,520 denier, 22,800 dtex), and five reels of hollow filaments (21,054 denier, 23,393 dtex) to form a beam that has a nominal mixing ratio of 39% of round filaments, 37% trilobular, 12% serrated oval and 12% gaps with a total denier of 172,898 (192,108 dtex). The beam is stretched, curled and relaxed essentially as described in the Example 2 to provide a stretched beam of approximately 64,490 denier (71,655 dtex) of a thorough mixture containing these four curly filaments differently (8.9 CPI, 3.5 CPcm, 20 CTU), round, trilobular, serrated oval, and hollow, with a dpf nominal 4.3 (4.8 dtex). The properties of the filaments are presented in Table 4B. The stretched dpfs were significantly different although spun dpfs were very similar, which shows the difficulty of predicting in advance what what will happen when the mixed filaments are stretched jointly.

A conventional finish was applied as in the Example 1. The stretched beam was processed to show zero Defects of Product (DMTE, DCO, AST).

An enlarged photograph of part of this mixture of filaments in Figure "1".

Example 5

In Table 5, the properties of the filaments stretched are similarly summarized for filaments only two strands stretched differently from a beam stretched prepared essentially as described in Example 4 except because only two different cross sections, round and trilobular, were combined in a similar manner, in proportions of 51% round fibers and 49% lobular fibers.

TABLE 5B

9

The curling was measured as 8.9 CPI, 3.5 CPcm and 22.5 CTU The beam was processed to show zero Product Defects (DMTE, DCO, AST), although the dpfs stretched and the properties of the filaments are significantly different from those in the Table 4B. This confirms the difficulty of predicting the behavior of filaments during spinning.

Example 6

The filaments of round cross section, trilobular, and serrated oval of two different deniers (upper dpf called "OD-S" and lower dpf called "OD-I"), essentially spun as described for Example 4 (no hollow filaments were used in this Example); OD-I filaments were extruded at a speed of 75 lbs / h (34 kg / h) from a row of 450 capillaries; the OD-S and the other filaments were as described for Example 4. The yarn denier of the round, trilobular, and OD-S filaments were approximately the same while that of SO-I was 7.9 dpf (8.8 dtex). Properties after finishing spinning are indicated in Table 6A. Strain strain deformation curves Single of both serrated oval types are shown in Figure 6, the continuous line being for a superior denier filament of OD-S, and being the dashed line for a OD-I filament of lower denier.

Twenty filament coils were combined round, thirty-five coils of trilobular filaments and four coils of OD-S filaments (as in the Example 4) with five OD-I filament reels (17,775 denier, 19,750 dtex) to form a beam that has a nominal mixing ratio of 40% round, 38% trilobular, 12% OD-S and 10% OD-I with a beam denier total of 169,619 (188,466 dtex). Part of this beam was stretched, it curled and relaxed essentially as in Example 2 to provide a stretched beam (8.7 CPI, 3.4 CPcm, 14.8 CTU) of approximately 57,018 denier (63,353 dtex) of a thorough mixture containing round, trilobular, oval toothed dpf upper, all 3.9 dpf (4.3 dtex) and oval serrated dpf lower than 2.6 dpf (2.9 dtex) whose filament properties They are listed at the top of Table 6B. Another part of same beam was processed through another route, also using a cooker at 145 ° C, before the filling box inverter, and then relaxed at 145 ° C to provide a stretched beam (11.6 CPI, 3.0 CPcm, 10.7 CTU) of filaments whose properties are presented in the bottom of Table 6B.

TABLE 6A

10

TABLE 6B

eleven

A conventional finish was applied as in the Example 1. Both stretched beams were processed and showed zero Product Defects (DMTE, DCO, AST), again despite the fact that filaments have significantly different properties from those stretched in other examples.

Example 7

(Comparative)

Mixed filaments were spun, both section oval transverse toothed from the same row essentially as described in Example 1, but using polymer as described in Example 2, having the 516 large capillaries (located in the four outer rings of the row) an area of 0.0002717 square inch (0.175 mm2) flow to manufacture OD filaments of heavy dpf. Table 7A shows properties at finish spinning obtained from heavy dpf filaments and light.

TABLE 7A

Production / lbs Kind DPF Mod Have % E_ {B} 92 (42) Light (1,3) 3.5 (3.9) 12 0.6 175 Heavy (1.4) 4.6 (5.2) eleven 0.7 291

Thirty-four coils were combined to form a beam with a nominal mixing ratio of 40/60 filaments light / heavy This beam was stretched at a 2.6X ratio but by the rest stretched, curled and relaxed essentially as it described in Example 1 to provide a stretched beam of approximately 56,000 denier (62,000 dtex) of a thorough mixture containing lower and upper denier filaments, with a dpf nominal of approximately 1.85 (2.1 dtex), whose properties of the filaments are presented in Table 7B.

TABLE 7B

% conc. in mixture DPF MOD Have E_ {B} Heavy (1.4) 60 2.2 (2.5) 40 1.8 12 Lightweight (1,3) 40 1.4 (1,6) 42 2.3 fifteen

The conventional finish was applied as in the Example 1. The beam (CPI 9.6, CPcm 3.8) was collected in a box for conventional beam and sent to a factory for processing later, mixing it with wool for conversion in threads and then in textile material, and were processed very successfully, showing Zero Product Defects (DMTE, DCO, AST). This Example 7 is similar to Example 1 of United States Patent No. 5,591,523 in which the filaments of toothed oval cross section of different deniers stretched simultaneously on the same beam, but different in that in this Example 7 both types of filaments were made by spinning through different capillaries in The same row.

The absence of said Product Defects in the bundles of stretched mixed filaments according to the invention is very different from the experience when stretching bundles of filaments comparable polyester homopolymer blends (2G-T) without any chain branching.

Claims (10)

1. A procedure to stretch simultaneously a mixture of polyester filaments in the same filament bundle of polyester, wherein said mixture is a mixture of filaments of different cross sections, having the mixture that includes polyester filaments cross sections selected from at least two of the following types of cross sections: serrated oval; trilobular; shaped tape; solid; hollow with multiple cavities; and round, and in which said polyester is of branched chain with between 0.1 and 0.8% molar of branching chain. 2. The method of claim 1, in the that the filament mixture comprises filaments that have one of the following cross section combinations: oval serrated and round; round, hollow and serrated oval; round, hollow and serrated oval with grooves; round, trilobular, serrated and hollow oval;  round and trilobular; and round, trilobular and serrated oval. 3. The method of claim 1, in the that the polyester filament mixture includes filaments of Different deniers per filament. 4. The method of claim 3, in the that a first filament in the mixture has some deniers per filament that are at least 1.1 times larger than deniers by filament of a second filament. 5. The method of claim 1, in the that the filaments are stretched through capillaries of at least two different cross sections. 6. A mixture of polyester filaments, in the that said mixture is a mixture of filaments of different cross sections, having the mixture that includes filaments polyester cross sections selected from at least two of the following types of cross sections; oval toothed trilobular; shaped tape; solid; hollow with multiple cavities; and round, and in which said polyester is of branched chain with between 0.1 and 0.8% molar of branching chain, and in which the shrinkage per sample is between 0.5 and 3%. 7. The mixture of claim 6, wherein the filament mixture comprises filaments that have one of the following combinations of cross sections: serrated oval and round; round, hollow and serrated oval; round, hollow and oval notched with grooves; round, trilobular, serrated and hollow oval; round and trilobular; and round, trilobular and serrated oval. 8. The mixture of claim 6, wherein said mixture is a mixture of different deniers per filament. 9. The mixture of claim 8, wherein a first filament in the mix has some deniers per filament that they are at least 1.1 times larger than the deniers per filament of A second filament. 10. A mixture of polyester filaments, obtainable by simultaneously stretching a mixture of filaments of polyester in the same beam of polyester filaments, in which said mixture is a mixture of filaments of different sections transversal, having the mixture that includes filaments of polyester cross sections selected from at least two of the following types of cross sections; serrated oval; trilobular; shaped tape; solid; hollow with multiple cavities; and round, and in which said polyester is chain branched with between 0.1 and 0.8% molar of chain branching, and in which the contraction per test is between 0.5 and 3%.