MXPA00008759A - Improving comfort by mixing deniers - Google Patents

Abstract

Comfort properties of fibers of longitudinally-grooved fibers of scalloped-oval cross section are improved by providing such fibers as a mixture of different dpf and using a cationic-dyeable alkali metal sulfonate isophthalate salt copolyester that is also modified with a chain-brancher so that the filaments of different dpf can be drawn simultaneously.

Description

IMPROVEMENT OF COMFORT THROUGH THE MIXTURE OF DENIERS FIELD OF THE INVENTION This invention relates to the improvement of comfort by blending deniers by filament of polyester fibers of scalloped or oval toothed cross section and of dyeable cationic copolyester composition which has been modified with a chain brancher provided by a skill to be stretched simultaneously, and to such stretch process and products from these.

BACKGROUND OF THE INVENTION Polyesters have been produced commercially on a large scale for processing into shaped articles such as fibers, mainly poly (ethylene terephthalate). Synthetic polyester yarns have been known and used commercially for several decades, having been first suggested by. H. Carothers, U.S. Patent No. 2,071,251, and thereafter, U.S. Patent No. 2,465,319. Hinfield and Dickson .REF .: 121836 suggest poly (ethylene terephthalate) which is the most widely manufactured and used synthetic polymer to date for textile fibers and which is often referred to as the PET homopolymer. PET homopolymer has generally been preferred over copolymers, due to its low cost, and also because its properties have been completely adequate, or even preferred, for more end uses. It is known, however, that the PET homopolymer requires special dyeing conditions (high temperature requiring super atmospheric pressure) not required, for nylon fibers, for example, in this way, copolés teres have been suggested. and are used commercially for some purposes, for example, dyeable cationic copolyes such as those which have been described by Griffing and Remington in the U.S. Patent No. 3,018,272 and by Hansen et al., In U.S. Patent Nos. 5,171,309 (DP-6"335) and 5,250,245 (DP-6335-B).

Polyester fibers are either (1) continuous filaments or (2) fibers that are discontinuous, in which the latter are often referred to as cut fiber or cutting fibers, and are made by being first formed by extrusion into continuous filaments of polyester, which are processed in the form of a tow of continuous filaments of polyester before being converted into fibers. . An important state in the processing of continuous filaments of polyester has been the "stretching" to increase the orientation of the long chain polyester molecules, and thereby, improve the properties of the filaments.

Mostly, the goal of synthetic fiber producers has been to replicate the advantageous properties of natural fibers, the most common of which have been cotton and wool fibers. The majority of the polyester cut fibers have been PET polopolyesters of round cross section and have been mixed with cotton. The PET homopolymer is hydrophobic, while cotton absorbs moisture, and cotton fabrics have been preferred over synthetic polymer fabrics by many people, because it is believed that many cotton fabrics have been more comfortable to use than cotton. Most of the fabrics of synthetic polymer fibers, which have been mostly of round cross section as previously stated here. Filaments of round cross section are the looser and more economical synthetic filaments for spinning and dyeing, whereby virtually all synthetic filaments have a round cross section, except for specialty filaments which are more expensive to manufacture and more expensive to dye due to its increased surface area.

For several years, PET cross-section fibers of generally scalloped or oval toothed cross-section running along the length of the fibers have been commercially available from Du Pont de Nemours and Company and have given significant advantages over both cotton and PET homopolymer fibers of round cross section due to the increased comfort properties provided by these polyester fibers having a cross section (not round). Their longitudinal grooves have provided increased benefits in the wick or wet wick over the fibers of round cross section, and the fact that moisture is in the wick along with the fibers instead of being absorbed has been an advantage in contrast to cotton. The additional advantages may, however, be desirable and obtainable in accordance with the present invention.

Recently, U.S. Patent Nos. 5,591,523 (DP-6255) and 5,626,961 (DP-6365-A) and co-pending application No. 08 / 662,804 (DP-6400) filed on June 12, 1996, and now assigned, corresponding respectively to WO 97/02372, WO 97/02373 and WO 97/02374, descriptions of which are hereby incorporated by reference, having disclosed inventions relating to polyester tows which are suitable for conversion to textile fiber ribbons in a system of woolen or worsted woolen cloth or woolen fabric and processed downstream in such systems, eventually in fabrics and clothing. The present invention has been developed in the course of such work and is described with particular reference to its value in stretched polyester filaments in tow. The tows described in U.S. Patent No. 5,591,523 consist essentially of polyester filaments of scalloped cross section or oval toothed with grooves running along the length of the filaments and their mixtures of filaments of higher denier by filament and lower denier. per filament with specified ranges and are suitable for processing in a system of combed wool fabric or yarn or woolen fabric. In addition, for the tow that is suitable for processes in a worsted wool or worsted or woolen fabric system, it may be desirable to provide polyester fibers for processing in a cotton system, as such those that are fully processed in a manner different.

The processing of the cotton system is carried out on a polyester fiber of cut fibers and, of course, on cotton, which is a natural fiber of similar length to the fiber of polyester fiber. The cut fiber is usually sold and packaged in compacted bundles or bales, as opposed to processing in a combed wool or woolen cloth or wool fabric system. The bundles or bullets are opened and the fibers are transported from a pneumatic or mechanical system to a card. The card separates the tassels of fibers, aligns them in a network of paralyzed fibers which are formed in a continuous tape as those left in the card. The tapes can then be mixed with other fibers such as cotton in a stretch structure, and passed through one or more additional stretch structures to improve mixing and overall final uniformity. The tape is then spun into yarns in a spinning system, such as an open-end spinning structure, an air-jet spinning structure or a ring spinning structure. In some cases, the stretch structure belt is converted into a roving frame to further reduce the weight of the belt, before being spun into yarns in a ring spinning structure, to make the yarn a size (cont. ) and appropriate level of turns before the formation of the fabric.

As for example, it has been described in US Pat. No. 5, 591,523 (DP-6255), the filaments (cross-section generally festooned or serrated and) of different denier per filament (dpf) are desired, and so surprisingly it is expressed in Example 1 of such a patent, that it is possible to spin without stretching homopoly (ethylene terephthalate) (modified with tetraethyl orthosilicate) filaments that have been significantly different denier yarns on the same spinning machine without adjusting the natural stretch ratio and then subsequently stretching an intimate mixture of these yarns spun simultaneously into the same tow at the same ratio of stretching, to provide filaments with excellent properties that were different due to their differing dpfs (column 6, lines 15-29). The present invention expands on this surprising finding and extends in the simultaneous stretching of mixed filament packages that were not specified in the patent.BRIEF DESCRIPTION OF THE INVENTION In accordance with one aspect of the invention, there is provided a blend of cross-section copolyester fibers generally festooned or oval toothed with grooves running along the length of the fibers, said cationic copolyester is dyeable by ratio of the presence of from about 1 to about 2.5 mole% of an alkali metal salt of a 5-sulphonic isophthalic acid, and they are branched chain with about 0.05 to about 0.8 mole% of a chain brancher, and said mixture is a mixture of fibers having an upper denier per filament and fibers having a lower denier per filament, wherein said upper denier per filament is at least 1.2 times said lower denier per filament; such mole% is conventionally calculated as the molecular weight of the dyeable cationic salt unit or the chain brancher unit, respectively, divided by the molecular weight of the polymer repeat unit 100 times, the repeat unit for 2G- T is ethylene terephthalate, by way of example. Such fiber blends can be in the form of cut fiber (cut) blends in various forms, including yarns, and fabrics and dresses as well as the yarns themselves, and it will be understood that blends of the polyester fibers may also be present. in mixtures with other fibers, such as those of other synthetic polymers, including polyamides (nylon of various types) and polyolefins ,. for example, and / or of natural fibers, such as cotton, in any of such forms.

The terms "filament" and "fiber" are used inclusively herein, and are not generally proposed to be mutually exclusive; sometimes, however, these general terms are modified, as in terms such as "continuous filament" and "cut fiber".

According to another aspect of the invention, there is provided a stretching process of a blend of copolyester fibers of generally scalloped or oval toothed cross section, with grooves running along the length of the fibers, said copolyester is dyeable cationic because of the presence of about 1 to about 2.5 mole% of an alkali metal salt of a 5-sulphonic isophthalic acid, and is branched chain with about 0.05 to about 0.8 mole% of the chain brancher, and said mixture is a mixture of fibers having an upper denier per filament and fibers having a lower denier per filament, wherein said upper denier per filament is at least 1.2 times said lower denier per filament.

Preferably, the upper denier is at least 1.5 times the lower denier.

Significantly, as will be explained in relation to the stress and strain curves in the Examples, there has been no stretching experienced in contrast to the experience when the filaments of the 2G-T homopolymer are stretched.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an enlarged photograph of a fiber mixture according to the invention, showing its cross sections, as explained hereinafter in more detail.

Figures 2 and 5 are stress and strain curves of individual filaments, as described more specifically in Examples I and III hereinafter.

Figures 3, 4 and 6 provide the data showing the improvement in Moisture Transport (Wick Ratio) and Dry Ratio for blending fabrics according to the invention, in contrast to denier fiber yarn fabrics individual, as explained in more detail in the Examples hereinafter.

DETAILED DESCRIPTION OF THE INVENTION It may be redundant to repeat that it has already been described in the art. As indicated, the preparation of the polyester polymers and the filament spinning therefrom has been described generally in the art. The stretching of polyester filaments has also been described in many references dating back to those by 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. Seo (London), Vol. A221, pages 541-557"The Cold Drawing of Hig Polymers." The polyester fiber blends of generally festooned or oval toothed cross section running along the length of the fibers that have already been described in US Pat. No. 5,591,523, such blends are of higher denier and lower denier as . specify here According to the present invention, the copolyester fibers should be a mixture of fibers having an upper denier per filament and lower denier fibers per filament, wherein said upper denier per filament should be at least 1.2 times said lower denier per filament. filament; denier by filament is often referred to as a dpf here later. The denier mixture according to the invention (sometimes referred to hereinafter as dual or double denier) provides improved comfort in fabrics as described hereinafter in contrast to fabrics of single denier fiber yarns such as those of scalloped cross section or oval teeth While the invention is not limited to any theory, it is believed that dual denier fibers are allowed to improve wicks with water due to the greater amount of separation between adjacent fibers to which they are not packed in this way closely together as they can be. the fibers of the same cross section but of the same dpf because the fibers of the present invention are not all of the same dpf Improvings have been demonstrated in the Examples hereinafter with varying proportions of the upper and lower dpf fibers and proportions varying from higher to lower: preferably, however, the upper: lower ratio should also not be wide, especially not more than about 5: 1. For the quantities of the upper and lower fiber, these can be calculated on the basis of relative numbers or relative weights of the fibers, as can be seen in Example 2 below, a n of Light filament number: Heavy of 2: 1 (with a dpf ratio of 1: 2) gives significant improvements in WTV (Water Vapor Transmission) and% of Moisture in the fabrics on the Number Proportions of the filaments Lightweight : Heavy that were almost 4: 1 and higher, thus smaller proportions of numbers are generally preferred, preferably of about 3: 1 or less, while recognizing that other considerations, such as the dpf ratio, may also affect such results, including the twists of the threads and the construction of fabrics. Example 2A, however, has shown that even a Lightweight: Heavy Weight Ratio of 10.5 to 1 gives a significant improvement in WVT and% Moisture after 2 hours over the comparison of single dpf. The examples indicate a so-called "nominal denier" for convenience, because many people do not use it in terms of yarn, tow or other bundles of fibers with denier blends, the "denier nominal" is the total denier of packages of fibers divided by the total number of fibers by the tow in filaments, yarns and other fiber bundles referred to herein. Recently, textile operators have shown an increased interest in lower dffs that are available from natural fibers, such as cotton, including an interest especially in subdenier fibers. Textile operators have generally preferred to. textile fibers, dpfs of less than about 3 dpf (3.3 dtex), but the invention is also applicable to copolyester fiber blends of any dpf.

For the cross sections of the fibers, any cross-section in a generally scalloped or oval toothed manner is applicable. U.S. Patent No. 5,591,523 mainly discloses such cross sections with 4 grooves running along the length of the fibers, the cross section fibers having 4 grooves have been described by Gorrafa in US Pat. No. 3, 914,488 more than 20 years ago, and by others, including Franklin and Clark et al., Some 10 years later in US Patents Nos. 4,707,467, and 4,634,625, respectively. The fibers of cross sections, scalloped or oval toothed, having 6 to 8 slots, are described in US Pat. No. 5,626,961 and in application No. 08 / 778,462, filed January 3, 1007, and now referenced, (Aneja DP-6365-A and Roop 'DP-6550), respectively, and such cross sections of scalloped or oval toothed fibers are also contemplated as being suitable in accordance with the present invention. Mixtures of cross sections may also be expected to provide increased comfort, especially mixtures of scalloped or oval cross sections, with numbers that differ from the slots, and are contemplated in accordance with the present invention. The aspect ratios of the cross sections of the scalloped or oval toothed fibers should generally be at least 1.3: 1 to provide sufficient difference of the round fibers. As the aspect ratio is increased, the benefit of the cross section, scalloped or oval toothed decreases, so aspect ratios of up to about 3: 1 are generally preferred, it is understood that this may depend on other factors, such as the number of slots. Similarly, a cross section, festooned or oval toothed, whose grooves are not "located on the minor axis of the oval, are generally preferred, for some purposes (different from a peanut type of cross section, for example). The proportions of the grooves here are calculated as the minimum thickness of a cross section of the filament (i.e., at least, the lower part of the groove on opposite sides of the cross section divided by the maximum thickness of the cross section at a adjacent bulge of the cross section, for example, d? / b? and d2 / b2 as described in the Patent U.S. No. 5,626,961, referred to herein above).

Polyester fibers only specifically described and exemplified in U.S. Patent Nos. 5,591,523 (Aneja DP-6255) and 5,626,961 (Aneja DP-6365-A); Co-pending applications Nos. 08 / 662,804 (Aneja DP-6400) and 08 / 778,463 (Roop DP-6550), and WO 97/02372, 97/02373 and 97/02374, all referred to hereinafter, were of PET homopolymers modified with a chain brancher. In contrast to such modified PET homopolymers, the fibers of the pre invention are of a dyeable cationic copolyester composition according to the pree of about 1 to about 2.5 mole% of an alkali metal salt of a 5-sulfonic isophthalic acid. Dyeable cationic copolyes have been described in the art, for example, by Griffing and Remington in U.S. Patent No. 3,018,272, and by Hanet al. in U.S. Patent Nos. 5,171,309 (DP-6335) and 5,250,245 (DP-6355-B), descriptions of which are herein incorporated herein by reference :. Such cationic copolyester compositions stainable for the fibers according to the pre invention should also be modified with from about 0.05 to about 0.8 mole% of a chain brancher, provided by a capacity to stretch the filamentary mixtures of dpfs which differ simultaneously from according to the pre invention, and also, if desired, spin dpfs that differ through different capillary holes in the same rows as described hereinafter in Example V. The amount of chain brancher is preferably at least about 0.2. and preferably up to about 0.3 mole% in accordance with the pre invention. The use of chain branders (ie, intermediates that form multi-functional polyesters, which have the requirement of more than two functional groups that are required for polymerization, such as glycol and a dibasic acid, both of which are difunctional) have been described in the art as as in MacLean et al., U.S. Patent Nos. 4,092,299 and 4,113,704, Mead. et al. in U.S. Patent No. 3,335,211, Oxford et al. WO / 92/12, 120, Duncan, U.S. SIR H1275, DuPont (Broaddus et al.) EPA2 294,912, Reese, U.S. Patent Nos. 4,833,032, 4,966,740 and 5,034,174, Goddley et al, in U.S. Patent No. 4,945,151, and relating to the art and cited herein, such as Vaginay, U.S. Patent No. 3,576.73. Some of these references use different terminology, such as viscosity builders, because the materials were added to increase the performance of the yarn, or for other reasons. Many of these previous techniques related to high-speed spun yarns, such as yarns fed for the formation of the stretch texture, as well as those continuous filaments that are oriented in the yarn, preferably amorphous, as they have been general preferred to date for stretching in the form of tow for conversion into cutting fibers, which are of special interest and preference in accordance with the pre invention. A low shrinkage of from about 0.5 to about 3% of the filament blends according to the invention distinguish our drawn filaments from the filaments of higher shrinkages made by spinning at high speed to make filaments oriented towards yarn to be used as yarns. fed for the formation of stretched textures, often referred to as POY. This shrinkage is the shrinkage boil which refers to the lower part of Knox's col 6 of US Pat. No. 4,156,071, and can be measured in the manner described here by Knox. As indicated, U.S. Patent No. 5,591,523 and WO 97/02372 have already described in Example I, the simultaneous stretching of a tow of homopoly (ethylene terephthalate) (modified co-orthosilicate of tetraethyl) blended dp filaments and It was surprising that these may be accompanied to give strands that were satisfactory and with no dark dyes.

PROOF PROCEDURES Most of the procedures that were used are well known and / or described in the art. To avoid any doubt, the explanations of the procedures that were used are given in the following paragraphs.

Units Measurements were made using conventional US textile units, including denier, which is a metric unit. To suggest prescriptive practices elsewhere, the dtex and CPcm equivalents of the DPF and CPI measurements are given in parentheses after the current measurements. For tensile or voltage measurements (MOD, for initial module, and TEN for tenacity), however, the current measurements in gpd have been converted to g / dtex and the latter are given in the Tables, while the stress curves and deformations in the Figures show original metric tensile values on the Y axis.

Instron. The average strain strain curves were obtained as follows as an average of 10 individual filaments of each type taken from the tow packages. Ten samples of each type of filament were separated from the bundles of tow using an amplified lamella (LUXO Iluminated Magnifier). The denier by filament (DPF) of each sample filament was measured in a VIBROSCOPE (HP Model 201C Audio Oscillator). The sample filaments were mounted one at a time in an INSTRON (Model 1122 or 1123) and the behavior of stresses and deformations was measured. Ten breaks were recorded for each type of filament, and the average of the 10 samples was recorded for each type of filament, thus, as will be easily understood, the values read from a strain and strain curve of an individual filament they do not necessarily correlate with the tensile properties calculated and listed as an average in the Tables.

The dimensions for the cross sections of the fibers were obtained using the following procedure. A fiber specimen is mounted on a Hardy microtome (Hardy US Department of Agriculture circa 378, 1933) and divided into thin sections in accordance with the methods essentially as described 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 in a state of super FIBERQUANT video microscope system (Vashaw Scientific Co., 3597 Parkway Lane, Suite 100, Norcross, Georgia 30092) and presented in the super FIBERQUANT CRT under modifications as necessary. The image of a "thin individual ection of a fiber and s-" my "in the critical dimensions of the fiber is selected.This process is repeated for each filament in the review field to general a set of statistically significant sample, and the averages are given here.

The aspect and slot proportions were calculated as described in the application (DP-6585-A) filed on December 17, 1997, by Anderson et al.

Relative Viscosity (LRV) It is the __ viscosity of the polymer dissolved in a HFIP solvent (hexafluoro-isopropanol containing 100 ppm of 98% reactive grade sulfuric acid). The viscosity measuring device is a capillarity viscometer obtainable from a number of commercial suppliers (Design Scientific, Cannon, etc.). The relative viscosity in centistokes was measured in 4.75% by weight of polymer solution in HFIP solvent at 25 ° C compared to the viscosity of the pure HFIP solvent at 25 ° C. The H2S04 used for the measurement of LRV destroys the crosslinked bonds, specifically of silicone in the case of the chain linker tetraethyl orthosilicate.

Acid-free Relative Viscosity (NRV) It is the viscosity of the polymer similarly dissolved, measured and compared in the solvent of hexafluoro isopropanol but without some sulfuric acid. Since the acid is not present, the crosslinks are left intact when the NRV is measured.

Delta RV (? RV) It is the expression we have used here to define the difference between the NRV and the LRV measured as described above, and that it expresses the amount of cross-links destroyed by the acid when measuring the LRV. * The performance properties for measuring wicking proportions, drying and water vapor transmission were measured on fabrics made as follows. The 1.5 inch cut length (38 mm) cut fiber was converted to 30/1 ce, as of 22/1 ce, as indicated, and such yarn is woven into a single, supplied, machine jacket 48 of cut 22. The woven fabric is washed for 10 minutes at 160 ° F (71 ° C) with an aqueous solution containing 30 grams of Merpol HSC and 30 gms of tetrasodium pyrophosphate, rinsed at room temperature for 5 minutes, stained for 20 minutes. minutes at 220 ° F (104 ° C) at 15 psi (1 kg / cm2) at 69 gallons (260 liters) Klauder, on a Weldon dyeing machine, Giles Model 25 PW beck with 3% GBR Blue Sevron OWF 200% , 4% OWF carrier (Intercarrier 9P), 5% sodium sulfate OWF and 25 ml acetic acid, rinsed until it became clear, dried in a homemade laundry type dryer (Kenmore) for 10 minutes at approximately 150 ° F (65 ° C), and pressed with a dry iron (heated to a permanent pressure operation).

The resulting dyeing and finished fabrics were evaluated by aesthetics, "sides" and covers and also by their performance properties, as follows.

Moisture Transport (Wick Ratio) The capacity of a material to move water by the action of capillarity. Specimens suspended vertically from the woven fabrics were submerged to a given depth in the water. At specified time intervals, the distance the water has traveled to the specimen was measured and reported. Four specimens of 1 inch x 7 inches (2.5 cm x 18 cm) with the largest parallel dimensions with the column or machine direction from a sample were conditioned at 70 +/- 2 ° F (21 ° C) and 65 +/- 2% relative humidity for a minimum of 16 hours. One end of the long direction of each specimen was sheared on a support rack in a vertical position so that the other (free) end is placed in a container, where it reaches a depth of 1.8 inches- (4.6 cm) ) is distilled, the water is demineralized at 70 +/- 2 ° F (21 ° F), while simultaneously starting to time. The height that the water reached above the water level in the container was measured at 0.1 inches closer (0.3 cm) at intervals of 0, 5, and 30 minutes. The average height (in inches) was reported at each time interval (in minutes) of all specimens for each of the samples.

Dry Ratio It is the capacity of a material to evaporate water. The fabric specimens were saturated in water and weighed at specified time intervals while drying. The loss of water over time was measured and recorded. Three specimens of 4 inches x 6 inches (10 cm x 15 cm) were conditioned at 70 +/- 2 ° F (21 ° C) and 65 +/- 2% relative humidity for a minimum of 24 hours. Samples were weighed and recorded as dry weight. The specimens were immersed in a 250 ml laboratory beaker filled with regular tap water for 10 minutes with frequent agitation to remove the air bubbles. The specimens were removed from the laboratory beaker and the excess water was removed by hand squeezing and staining between the paper towels gave the wet weight equal to twice the dry weight. The specimens are then hung up while they start timing. Their weights were recorded at 20 minute intervals for 120 minutes. The percent moisture was calculated as: Humidity (%) = [(wet weight - dry weight) / (dry weight] x 100 Average humidity (%) was reported at each time interval (in minutes) of all specimens for each sample. Thus, the "Dry Ratio" was recorded at the% Humidity that was retained, a% lower Humidity indicating a faster Dry Ratio, which is generally preferred.

Water Vapor Transmission It is the flow of water dispersed in the air (humidity) through a material which occurs when the humidity on both sides of the material is different. The specimens are mounted in a cup with water, and the complete assembly is weighed before and after 24 hours in a controlled atmosphere. The weight gained or lost is calculated as the change in weight per unit area of the specimen (g / 24 hours / sq m). The method used is the same as that of the ASTM E-96 Standard Test Methods for Water Steam Transmission of Materials with the following exceptions. A relative humidity of 55% is used instead of 50%. Only the Water Method was used (and not the Desiccant Method).

Frequency of Frundy or Wavy It was measured as the number of puckers or crimps per inch (CPI) after puckering or crimping of the tow. The gathered or wavy. It was presented by numerous peaks and basins in the fiber. Ten filaments were removed from the tow packages and randomized and placed (one at a time) in a relaxed state in fasteners of a fiber length measuring device. The fasteners are manually operated and initially moved in close enough together to prevent fiber narrowing while being placed in the fastener. One end of a fiber is placed in the left bracket and the other end in the right bracket of the measuring device. The left fastener is rotated to move any twist in the fiber. The support of the right bra is moved slowly and evenly to the right (extending the fiber) until all the little tension has been removed from the fiber but without the removal of any fastener. Using an illuminated amplifier, the number of peaks on the upper and lower sides of the fiber were counted. The support of the right bra is then moved slowly and evenly to the right until all the puckering or ripples together have disappeared. Care is taken not to shake the fiber. This length of the fiber is recorded. The frequency of puckering or undulation for each filament is calculated as: Total number of peaks 2 x Filament length (not puckered or wavy The average of the 10 measurements of all the fibers were recorded by CPI (shirred or crimped per inch), the metric equivalent is CPcm.

CTU (purplish or corrugation socket) It was also measured in the tow and is. a measure of the length of the extended tow, thereby removing the ruffled or wavy, divided by the unexpected length (ie, as puckered or wavy), expressed as a percentage, as described in Anderson, et al., U.S. Patent No. 5,219,582.

Product Defects They were classified here into three categories: - 1) Equivalent Fabric Defect (EFD) 2) Dark Tissue Defects (DDD) 3) Fragmentation (SPL).

The first two defects (EFD and DDD) are fibers and agglutinates that stain darker than normal fibers. The DDDs have a diameter of less than 4X the diameter of the normal (stretched) fiber. The EFDs have a diameter 4X or normal fiber diameter. Both defects could be larger than 0.25 inches (6.35 mm). The samples are. processed through a top roller of card type. The tapes are stained light blue and. they are examined visually under an illuminated amplified foil.

Fibers that stain darker than the volume of the samples are removed, classified as EFDs or DDDs and counted. Each type of defect is reported as defect numbers per 0.1 pound (0.045 kg) of tapes. Ribbons are fibers of exaggerated size or agglutinated fibers. To be classified as fragments, this defect can also be greater than 0.25 inches (6.35 mm) but its total diameter could be greater than 0.0025 inches (0.0635 mm). The fragments are concentrated in the waste of smooth strips when a fragment sample is processed through a flat card. The smooth strip waste is visually examined against a black background. The fragments are removed, classified by size, counted and expressed in a weight of the base sample. More details are given in U.S. Patent No. 5,591,523.

The invention will be further illustrated in the following Examples; all parts, percentages and proportions are by weight unless otherwise indicated, the polymer entries by weight are calculated with respect to the weight of the polymer.

EXAMPLE 1 The upper (heavy) denier filaments of the copolyester were made of ethylene terephthalate copolymerized with 2.08 mole% of sodium 5-sul phisophthalate dimethyl and 0.20% by weight of tetraethyl orthosilicate, and containing 0.3% by weight of titanium dioxide and having relative viscosities of 10.5 LRV and 12.9 NRV as well as 2.4? RV. The filaments of approximately 4.6 dpf (5.1 dtex) were spun by melting at 274 ° C from this copolyester, being extruded at a rate of 41.6 lbs / hr (18.9 Kg) and coiled in coils. The shape of the capillary hole was three diamonds joined together as described in application No. 08 / 662,804 (DP-6400) filed on June 12, 1996, by Aneja and as shown in Figure 2 thereof, for thus elaborate scalloped or oval toothed cross-section filaments with 4 grooves similar to those described herein. The filaments were spun from a row containing 450 such capillaries at a removal rate of 1500 ypm (about 1370 meters / minute), and rapidly cooled as described by Anderson, et al., In U.S. Patent No. 5,219,582 to provide a package of 450 filaments of a total denier 2070 (2300 dtex).

The lower denier (light) filaments of the same copolyester and cross-section, scalloped or oval toothed 4-slit, but approximately 2.6 dpf (2.9 dtex) were similarly spun by fusion, but extruded at a rate of 79.3 lbs. / hr / 36 kg / hr), and spun from a row containing 1506 capillaries to provide 1506 filaments of total coil denier of approximately 3.910 (4350 dtex).

The properties for both types of filaments are given in Table IA and the stress and strain curves are shown in the Figure 2, -the dotted lines are for light filaments and the continuous lines for heavy filaments.

TABLE IT Twenty lower denier filament coils (78,312 denier (87,013 dtex) (30,120 number of light filaments) and 22 upper denier filament coils (45,540 denier (50,600 dtex), 9900 number of heavy filaments) formed a nominal mixing ratio of 60% light / 40% heavy by denier and 75% light / 25% heavy by number of filaments combined in a nasa to form a mixed dpf tow for simultaneous stretching The tow was stretched to a stretch ratio of 2.7X in stretch by water spray at 85 ° C. The tow was then passed through a packing gland and subsequently relaxed at 123 ° C to give a tow of approximately 50,000 denier (55,555 dtex) of an intimate mixture of nominal denier of approximately 1.4 dpf (1.6 dtex) but containing three times as much of the light fibers as of the heavy fibers, but in a quantity of 60/40 by weight of light filaments (approx. 1 dpf and 1.1 dtex) and approximately 40% heavy (approximately 2 dpf and 2.2 dtex) with a finishing level of 0.20% OWF, and the product was scrutinized for product defects. The properties of the stretched fiber are given in Table IB.

TABLE IB The defect levels of the Product Quality were all zero in defects, so it is clear that the quality of the product was not adversely impacted by the simultaneous stretching of a mixture of different deniers such as copolyester fiber yarns. In addition, the performance of the stretching machine was not reduced by the breaking of the filaments or the wrapping in rolls.

The tows were cut to a fiber length of 1.5 inches (38 mm) and the mixed denier fibers were converted to threads (30/1 ce) and the fabric as described to a fabric that was tanned and finished, thus its comfort / performance and other characteristics may be evaluated and compared with a similar fabric made from the Comparison A product as described hereinafter.

COMPARISON A In contrast, the filaments of cross section and approximately 3.2 dpf (3.6 dtex) were spun by similarly melting from this same copolyester, being extruded at a rate of 92.4 Ibs / hour (41.9 kg / hr), from a position spinning machine 14 but otherwise, essentially as described for the heavy denier filaments of Example 1 to give a total denier tow of approximately 67,500 (75,000 dtex).

The tow was stretched, shirred and relaxed essentially as for Example 1, but at a stretch ratio of 2.6X to give a stretched tow of approximately 29,500 deniers (32,800 dtex) of filaments, all of 1.4"dpf similar (1.6 dtex) The properties of both filaments as they are spun and stretched are given in Table IC.

TABLE IC This tow of individual denier filaments was also cut into fibers, converted into yarns that were woven into a woven fabric that was finished and finished.

Both fabrics have the following nominal properties: they weigh approximately 5.53 oz / yd2 (187 g / m2) and the columns x rows per inch of approximately 29 x 35 (approximately 11 x 14 per cm).

The Moisture Transport properties (Wick Ratio) were measured on the fabrics and compared in Figure 3, where the values for the double denier fiber fabrics of Example 1 are plotted as squares in contrast to the values for the Single denier fiber, Comparison A, in which they are traced as diamonds and the weights are plotted against time (in minutes). Figure 3 shows an advantage of the fabric of Example 1 in its improved comfort as reflected by its higher Humidity Transport values, ie, the fabric of the mixed denier product of the invention showed superior Moisture Transport values in contrast with the fabrics of the single denier filament product of Comparison A.

The proportion of the Dry Fabric was measured and compared on a similar basis in Figure 4. Figure 4 confirms the superior comfort provided by the fabric of Example 1, as reflected by an increased Drying Rate for the fabric of the product. of mixed denier of the invention in contrast to the fabric of the single denier filament product of Comparison A.

The fabric of Example 1 also showed the Upper water vapor transmission (3630 gm / 24 hrs / m2) in contrast to that of the fabric of the_ Comparison A (1583 gm / 24 hrs / m2).

EXAMPLE 2 Table II summarizes the Water Vapor Transmission (WVT) values and moisture% values for the fibers prepared essentially as described for Example 1 (some polymer compositions and deniers) but where the Number Ratio ( light / heavy filaments) was varied by adjusting the numbers of upper and lower filament coils of dpf used in the stretched pots.

Thus, for 2: 1 light weight (Point D), they were 2 times as many fibers dpf 1 (light) as 2 fibers dpf (heavy).

TABLE II All double denier fiber fabrics showed improvements in these measurements on the individual Denier Comparison, Point D shows the greatest improvement.

EXAMPLE 3 The denier filaments differing were spun simultaneously from the different positions in the same spinnere machine essentially as described in Example 1, except as follows. The copolyester was made with 2.0 mole% of dimethyl sodium 5-sulfoisophthalate and have relative viscosities of 10.2 LRV and 12.4 NRV (2.2? R). It is melted at 272 ° C. It was extruded at a rate of 80 lbs / hr per position from 15 positions in all. Nine positions (5 positions on one side of the machine and 4 positions on the other) the filaments of lower spinning denier (through 1506 capillaries at each position.) Six filament positions of upper spinning denier (3 positions on each side) through 711 capillaries to each position. All the filaments were spun at a removal rate of 1600 ypm and collected in a can as a sponge which was a mixture of light and heavy denier filaments of the total denier of approximately 56,068 (62,300). The properties of the filaments as yarns are given in Table IIIA, while the stress and strain curves are shown in Figure 5, as in Figure 2.

TABLE IIIA Twenty-six cans of yarn supplied were combined together with amounts to 463,320 total denier filaments of approximately 1.5 million (1.7 million dtex) and stretched, pursed or undulated and subjected to relaxation essentially as for Example 1 to give a size final tow of approximately 650,000 denier (720,000 dtex) containing light and heavy denier filaments, rated nominal denier of 1.4 (1.6 dtex), and a fiber finish level of 0.25% by weight. The stretching properties are given in Table IIIB.

TABLE IIIB Eff Dpf - 14 The product was subjected to scrutiny for the level of product quality defect of EFD, DDD, and SPL, of which all registered zero defects, so it is clear that the quality of the product was not adversely impacted by the simultaneous stretching of the product. a mixture of different denier like spun copolyester fibers. In addition, the performance of the stretch machine was not reduced by the breaking of the fibers or the wrapping in rolls.

The tow was also cut into fibers, converted into 22/1 cb yarns that were woven into a fabric that was dyed and finished, otherwise, as in Example 1, and thus its embodiments / comfort and others. Characteristics of the fabrics may be evaluated as described. The surprising features were the improved performance properties of the dyeing and water vapor permeability ratio of fabrics obtained from denier fibers blended against fabrics made from essentially single deniers, as will now be reported.

COMPARISON B In contrast, filaments of similar cross section and approximately 3.4 dpf (3. "8 dtex) were made from the copolyester which was similar, except that 0.15% by weight of the tetraethyl orthosilicate was used to make the polymer having relative viscosities of 10.3 LRV and 12.9 NRVA, thus the filaments 2.6? RV are extruded at a rate of 92.4 lbs / hour (41.9 kg / hour) from a spinning machine in position 13, each position has a row containing 1506 capillaries, at a removal rate of 1500 ypm. total of tow using 28 cans for the nasa was approximately 1.9 million (2.1 million dtx) .. The tow was stretched to a stretch ratio of 2.5X but otherwise stretched, shirred or rippled and submitted to relax essentially as described by Example 1 to give a stretched tow of approximately 767,000 deniers (852,000 dtex) of 1.4 dpf filaments (1.6 dtex) .The properties of spinning and drawing filament are given in Tala IIIC.

TABLE IIIC The stretched tow from each of Example III and Comparison B were cut into fibers and converted into 22/1 ce yarns, which were woven into fabrics that were dyed and finished, essentially as described. Both fabrics have the following nominal properties: they weigh approximately 6.60 oz / yd2 (324 g / m2) and their columns x rows per inches are approximately 26 x 32 (approximately 10 x 13 per cm). The Dry Proportion properties were measured on the fabrics and compared in Figure 6 where the values for the double denier fiber fabrics of Example III were plotted as solid squares, in contrast to the values for the individual denier fibers. , Comparison B, which are plotted as diamonds (as well as the values for Example IV here below, the moisture content remaining in the fabric (in percent) are plotted against time (in minutes). An advantage of the invention is superior comfort as reflected by the faster Dry Ratio for fabrics of mixed denier products of the invention, which showed a significant improvement over the fabric of Comparison B. The fabric obtained from of the dual denier yarn also showed a higher WVT (1797 g / 24 hrs / m2) versus Comparison B of single denier.

EXAMPLE IV In Table IV, the summary data for the spun fibers essentially as described for Example III, but where% and denier% were identified The number% of light and heavy fibers in a mixture can be adjusted by the variation of the number of capillaries and positions in the spinning machine to make filaments more or less light or heavy For this mixture 85/15 (light / heavy), 11 positions of 1506 capillaries per end were used for thin filaments and 4 positions with 711 capillaries per end for heavy filaments at a yield of approximately 80 lbs / hrs / end (36 kg) at a removal rate of 1800 yp (1650 mpm). The tows were stretched at a stretch ratio of 2.3X and otherwise processed essentially as described for Example III into fibers, yarns and woven fabrics. The fabric obtained from this dual denier yarn showed superior vapor permeability by humidity (1464 g / 24 hrs / m2) against the comparison B of single denier (1232 g / 24 hrs / m2) and the Dry Ratio, showed as open squares in Figure 6, which is. correlates with superior comfort as reflected by these properties TABLE VAT It has surprisingly been found that it is possible to make yarns from two different denier fibers of these polyester esters (ethylene terephthalate copolymer made from sodium 5-sulfoisophthalate dimethyl and modified with tetraethyl orthosilicate) which have been denier yarns significantly different therein spinning machine, and then stretched together (in a single tow) to provide filaments of different dpfs and then eventually resulting fabrics (and dresses) have superior comfort properties that are better than those of fabrics and dresses similarly made from filaments which were all from the same denier as shown in the Examples and Comparisons mentioned above.

EXAMPLE V The blended filaments were spun by melting at 272 ° C from the same copolyester as used in Example III, such blended filaments are a 50/50 blend of light / heavy filaments, both of scalloped or oval cross section, oval and both they were spinned by fusion simultaneously through different capillaries in the same row, each containing 1000 capillaries, at a total rate of 23.68 lbs / hrs (10.75 kg) and wound into coils at 1800 ypm (1650 mpm). The rows have 516 capillaries, each of flow area of 0.0003079 sq in (0.1986 sq mm) to make the heavy filaments and 484 capillaries each flow area of 0.0002224 sq in (0.1435 sq mm) to make the light filaments. The smallest capillaries were located in the five inner rings (of 9) while the largest capillaries were located in the four outer rings of the row. The shape of the hole for the capillaries was used in the aforementioned examples, such as when the spinning conditions remained. The properties of the resulting spun filaments are given in Table VA.

TABLE VA Sixty-eight coils of the filaments mixed as yarns were combined to form a denier tow of approximately 126,000 (140,000 dtex). The tow was stretched, creased or waved and subjected to relaxation essentially as described for Example IV to give an intimate blend of light and heavy denim filaments gathered or crimped with a finish level (in fiber) of 0.20% , its properties are given in Table VB, and its nominal denier per filament (that is, the denier of the total packets of tow divided by the number of filaments) is 1.15 dpf.

TABLE VB.

The product was processed and then subjected to scrutiny for the defects of the product, EFD, DDD, and SPL, of which • all recorded zero defects, as is clear the product quality of this copolyester of the ethylene terephthalate copolymer containing the tetraethyl silicate did not adversely impact the simultaneous stretching of a mixture of different deniers such as spun filaments, which were surprising and contrary to previous experiences in the titration of mixed denier process filaments made essentially of similar dough from the homopolymer without chain brander It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the foregoing, the property contained in the following is claimed as property:

Claims (2)

1. A mixture of copolyester fibers generally cross-sectioned scalloped or oval toothed, with grooves running along the length of the fibers, characterized in that said copolyester is cationic dyeable, for reasons of the presence of about 1 to about 2.5 mole% of an alkali metal salt of a 5-sulphonic isophthalic acid, and being branched chain with about 0.05 to about 0.8 mole% chain brancher, and said mixture is a mixture of fibers having a higher denier per filament and fibers having a lower denier per filament, wherein said upper denier per filament is at least 1.2 times said lower denier per filament.

2. A stretching process of a blend of copolyester fibers of generally scalloped or toothed cross section with grooves running along the length of the fibers, characterized in that said copolyester is cationic dyeable for reasons of the presence of about 1 to about 2.5 mole of an alkali metal salt of an isophthalic 5-sulphonic acid, and being branched chain with about 0.05 to about 0.8 mole% of the chain brancher, and said mixture is a mixture of fibers having an upper denier per filament and of fibers having a lower denier per filament, wherein said upper denier per filament is at least 1.2 times said lower denier per filament.