US20060093816A1

US20060093816A1 - Polymer filaments having profiled cross-section

Info

Publication number: US20060093816A1
Application number: US11/253,920
Authority: US
Inventors: Richard Shoemaker; Ronald Steele
Original assignee: Invista North America LLC
Current assignee: Invista North America LLC
Priority date: 2004-10-28
Filing date: 2005-10-19
Publication date: 2006-05-04

Abstract

The present invention is directed to a multi-filament yarn formed at least in part from filaments having cross-sectional zigzag shape with a 180 degree axis of symmetry. The filaments have a denier per filament generally in the range of about 0.1 to about 4.0. Fabrics made from yarns formed with the filaments have high moisture wicking, soft hand, and a silk-like lustrous appearance.

Description

CONTINUITY DATA

This invention claims priority to Provisional Application No. 60/622,744 filed Oct. 28, 2004, now pending.

FIELD OF THE INVENTION

This invention relates to synthetic polymer filaments having a five-legged zig-zagged profiled cross section normal to the longitudinal axis of the filament and a 180 degree axis of symmetry.

BACKGROUND OF THE INVENTION

Textile fibers or filaments from synthetic polymers, particularly polyamide polymers like nylon 6,6, nylon 6, and multi-filament yarns melt-extruded from the same polyamide polymers, are produced for many apparel uses. The most common cross-sectional (taken longitudinally to the long axis of the filament) shape for each filament comprising the multi-filament yarns is circular. However, many variations on the individual filament cross-sectional shapes exist. These include a “dogbone” cross-sectioned filament commercially available from Invista, S. á. r.l. (of Wichita, Kans. and Wilmington, Del. USA) and known as TACTEL® Diabolo. A bi-lobal filament cross-sectional shape is disclosed in U.S. Patent Application Number 2002-0034903-A1 (Shoemaker, et al.). Other known shapes include tri-lobed or even 6-lobed, disclosed in Japanese Kokoku patent document 01-20243 (Nihon Ester KK). Another multi-lobal cross-sectioned fiber, available from Invista, S. á. r. L. and known as Coolmax™, is shown in U.S. Pat. No. 5,152,014. A seven-legged zigzagged cross-section fiber was disclosed in U.S. patent application Ser. Nos. 10/376,236 and 10/882,578 (Shoemaker, et. al.)
Filaments with cross-sectional shapes other than circular provide multi-filament yarns for fabrics and garments with varied visual aesthetics including those known in the art as glitter, sparkle, matt appearance, and increased opacity or cover. Lighter fabric weight and fabric flatness are also achieved through variations in the individual filament cross-sectional shape. Many synthetic fibers used in apparel fabrics contain profiled cross-sections which enhance the ability of filaments to absorb or wick moisture.
Moisture wicking, which refers to the capillary movement of water through or along the fibers, is considered a desirable feature in apparel fabrics as it improves comfort to the wearer by spreading moisture away from the skin so that it can evaporate more readily. In addition, combinations of cross-sections, denier per filament (dpf), and finish preparations applied to filaments and fabrics have been developed to enhance the ability of filaments to absorb or wick moisture. For example, “two-sided” fabrics have been developed to help move moisture from the inside to the outside of the fabric due to the surface chemistry. Typically, the two-sided fabrics have fine denier per filament (dpf) filaments primarily on the outside, and coarser dpf filaments primarily on the inside. Although this “two-sided” fabric is readily accomplished in weft knit fabrics through knitting construction, there is room for further improvement in wicking through optimum shape of the individual filaments. In addition, warp knit and woven fabrics are difficult and expensive to construct in a manner to maintain filament location primarily on one side or the other. Therefore, especially in wovens and warp knits, a filament that provides superior moisture wicking is needed to improve wearer comfort, especially for active wear.
There is a continuing need to provide multifilament synthetic yarns that provide enhanced moisture wicking properties to fabrics as well as a soft fabric hand and silk-like luster for apparel.

SUMMARY OF THE INVENTION

The present invention relates to a multi-filament yarn formed at least in part from synthetic polymer filaments having five-legged zigzagged cross-sectional shapes (as viewed normal to the longitudinal axis of the filaments).
In one embodiment, the filament cross-section may include at least five contiguous segments in zigzag configuration. Adjacent segments form an angle between about 40 degrees and about 60 degrees. The filament cross-section has a nominal width, a nominal length and a nominal thickness. The ratio of the nominal width to the nominal thickness can be less than about 3, and the indentation to thickness ratio for example can be between about 0.25 and about 0.6. For example, the filament may have a denier per filament between about 0.1 and about 4.0.
The synthetic polymer filament comprises a polyamide synthetic polymer selected from the group consisting of: polyhexamethylene adipamide; polycaproamide; polyenanthamide; nylon 10; polydodecanolactam; polytetramethylene adipamide; polyhexamethylene sebacamide homopolymer; a polyamide of n-dodecanedioic acid and hexamethylenediamine homopolymer; and a polyamide of dodecamethylenediamine and n-dodecanedioic acid.
A yarn may be formed at least in part from the synthetic polymer filament of the invention. Where the yarn is formed from a number of filaments, the synthetic polymer filament of the invention can comprise at least about 50% of the total number of filaments in said yarn. The yarn can have a denier of between about 15 and about 200.
A fabric may be formed with the yarn that includes synthetic polymer filaments according to the invention. A garment may be formed from the fabric made with the inventive yarn. A double-sided fabric may include the yarns that include the fibers or the fibers according to the invention on one side or both sides. A wetting agent may be applied to one side of the fabric to enhance moisture wicking. Suitable wetting agents include hydrophilic polyamide, hydrophilic silicone, and hydrophilic polyester.
The synthetic polymer filament according to the invention can have a cross-section that includes five contiguous segments in zigzag configuration, wherein each segment defines a proximal end and a distal end, wherein a distal end of a first segment is connected to a proximal end of a second segment, wherein a distal end of the second segment is connected to a proximal end of a third segment, wherein a distal end of the third segment is connected to a proximal end of a fourth segment, wherein a distal end of the fourth segment is connected to a proximal end of a fifth segment, and wherein a pivot point is defined along the third segment and the cross-section of the filament is symmetrical when rotated 180 degrees about said pivot point. In this zigzag cross-section configuration, the adjacent segments form an angle between about 40 degrees and about 60 degrees. A yarn may be formed at least in part from the synthetic polymer filament with the zigzag cross-section configuration, and a fabric may be constructed from such yarn or filaments. The fabric may be a double-sided fabric to which a wetting agent has been applied to one side to enhance moisture wicking.
The filaments according to the present invention are especially suitable in making apparel fabrics having a high moisture-wicking capability, combined with a soft hand and a silk-like lustrous appearance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a filament according to the invention having a five-legged zigzagged cross-sectional shapes.
FIG. 2 is a representation of a spinneret plate having four capillaries each comprising 5 slots for making filaments according to the invention having a five-legged zigzagged cross-sectional shapes.
FIG. 3 is a representation of a single spinneret capillary comprising five slots for making filaments having a five-legged zigzagged cross-sectional shapes.
FIG. 4 is a representation of a cross-section of an embodiment of the five-legged zigzagged cross-sectionally shaped filament according to the invention.
FIG. 5 is a photomicrograph of a fabric incorporating yarn formed from a combination of filaments including filaments with the five-legged zigzagged cross section.

DETAILED DESCRIPTION OF THE INVENTION

The cross-sectional shape of the filaments of the invention is a five-legged zigzagged shape having a 180-degree axis of symmetry as represented in FIG. 1. The five-legged zigzagged shape includes an upright “W” with a fifth additional leg. The 180 degree axis of symmetry means that when the cross-section is rotated 180 degrees about its center point P, the rotated cross-sectional shape is identical to the initial cross-sectional shape prior to rotation. The center point P shown in FIG. 1 is for reference in this description and would not be visible in this manner on a filament according to the invention.
The filament cross-sectional shape may comprise five contiguous segments originating from a first free end 1 a of the cross-sectional shape and traversing through the five segments (10, 20, 30, 40, and 50) to free end 5 of the fifth segment 50. The first segment 10 connects to the second segment 20 at a first vertex 1 b formed at the junction of the first segment 10 with the second segment 20. The second segment 20 connects to the third segment 30 at a second vertex 2 formed at the junction of the second segment 20 with the third segment 30. The third segment 30 connects to the fourth segment 40 at a third vertex 3 formed at the junction of the third segment 30 with the fourth segment 40. Finally, the fourth segment 40 connects to the fifth segment 50 at a fourth vertex 4 formed at the junction of the fourth segment 40 with the fifth segment 50. The cross-section terminates at second free end 5. In this configuration, the adjacent segments form an angle between about 40 degrees and about 60 degrees.
The filaments of the invention can comprise a synthetic thermoplastic polymer. More particularly the filaments of the present invention may comprise of homopolymers and copolymers of melt-spinnable polymers. For example, melt-spinnable polymers include polyamides, such as polyhexamethylene adipamide (nylon 6,6); polycaproamide (nylon 6); polyenanthamide (nylon 7); nylon 10; polydodecanolactam (nylon 12); polytetramethylene adipamide (nylon 4,6); polyhexamethylene sebacamide homopolymer (nylon 6,10); a polyamide of n-dodecanedioic acid and hexamethylenediamine homopolymer (nylon 6,12); and a polyamide of dodecamethylenediamine and n-dodecanedioic acid (nylon 12,12).
Fiber-forming polymers useful in accordance with the invention include at least one polyamide. The polymer can be a polyamide such as nylon 6, nylon 6,6, or a combination thereof. For example, the polyamide is nylon 6,6.
The polymers and resultant filaments, yarns, and apparel articles of the present invention can comprise conventional additives, which are added during the polymerization process or to the formed polymer or article, and may contribute towards improving the polymer or fiber properties. Examples of these additives include antistatics, antioxidants, antimicrobials, flameproofing agents, dyestuffs, light stabilizers, polymerization catalysts and auxiliaries, adhesion promoters, delustrants, such as titanium dioxide, matting agents, organic phosphates, and combinations thereof.
The polymers and resultant filaments, yarns, fabrics and apparel articles of the present invention can be treated on their surface with permanent or semi-permanent hydrophilic treatments or finishes. These treatments generally improve the moisture wicking property of the fabrics and apparel articles. Suitable surface treatments useful in the present invention include hydrophilic polymeric compositions, such as polyamides made with hydrophilic segments, such as poly(hexamethylene adipamide)-poly[poly(oxyethylene) adipamide] copolymers [CAS No. 92717-79-8], such as described in U.S. Pat. No. 4,468,505 incorporated herein by reference in its entirety; hydrophilizing silicone microemulsions, such as “Sandotor HV Liquid”, which is commercially available from Clariant; hydrophilic copolyesters, such as a copolyester containing both polyoxyethylene diester and alkylene diester segments; and certain nonionic surfactants, such as those described in Canadian Patent No. 1,234,656. These surface treatments vary in their ability to improve water wicking performance and vary in their durability or resistance to removal by washing. This variability in performance depends on several factors, including the composition of the treated fiber, the amount of wicking treatment applied to the fiber, and the resistance of the treatment to washing.
The poly(hexamethylene adipamide)-poly[poly(oxyethylene) adipamide copolymers have been found to be useful to treat articles of the present invention. The polymers are composed of polyoxyethylene adipamide segments and poly(hexamethylene adipamide) segments. The poly(oxyethylene) adipamide segments are formed from the reaction of a poly(oxyethylene) diamine [CAS No. 65605-36-9] with adipic acid. The poly(oxyethylene) diamine can include minor amounts, for example, less than 25 mol % oxypropylene groups with the oxyethylene groups.
The polyoxyethylene adipamide segments have high affinity for water and impart hydrophilic character to the copolymer and thus to the treated fiber, while the poly(hexamethylene adipamide) segments have low water solubility and thus impart permanence to the treatment on the fiber. These adipamide copolymers are especially useful when the polymer used in the substrate to be treated is nylon 6, nylon 6,6, or combinations thereof, and are for use when the polyamide is nylon 6,6.
The length of each of the polyoxyethylene adipamide and poly(hexamethylene adipamide) segments may be varied. Increasing the length of the polyoxyethylene adipamide segments increases the water wicking property of the treatment while simultaneously increasing its water solubility and thus decreasing its durability to washing. Increasing the length of the poly(hexamethylene adipamide) segments decreases its water solubility and thus increases its durability of the treatment to washing.
The suitable length of the polyoxyethylene adipamide segment is also determined to an extent by commercial availability of the poly(oxyethylene) diamine. Poly(oxyethylene) diamines with molecular weights of 600, 900, and 2000 are available from Huntsman Corporation, and hence are especially useful. They are known as XTJ-500, XTJ-501, and XTJ-502.
The relative amount of each of these segments to each other in the treatment composition may also be varied in any desired ratio. Increasing the proportion of polyoxyethylene adipamide segments increases the water wicking property of the treatment while simultaneously increasing its water solubility and thus decreasing its durability to washing. Conversely, increasing the proportion of the poly(hexamethylene adipamide) segments decreases its water solubility and thus increases its durability to washing. Balancing the relative amounts and lengths of the polyoxyethylene adipamide and poly(hexamethylene adipamide) segments in the copolymer can be done to maximize the water wicking performance while maintaining suitable durability to repeated washing. An example of the copolymer for the present invention employs poly(oxyethylene) diamines of molecular weight between about 900 and about 2000 with weight percentages of nylon 6-6 ranging from about 18-22%. The polymers can be made as described in U.S. Pat. No. 4,468,505.
These copolymers can be dissolved in any suitable solution when used in the present invention. A system has been found to be a solution of 1,2-propanediol and water. This combination provides a solution that may be either applied to fabrics by itself or in combination with other processing agents as described below. The amount of poly(hexamethylene adipamide)-poly[poly(oxyethylene) adipamide] copolymer in the solution may range from about 0.1% to about 40% by weight. The range for example is from about 8% to about 15%. At higher percentages of copolymer, the solution has a tendency to gel. Lower percentages are acceptable, but are less economical. For application to fabric, the solution may be further diluted with water to facilitate the application of only the desired amount of finish without over-application.
1,2-propanediol is used to facilitate dissolution of the copolymers in water. An amount of 1,2-propanediol is approximately equal in weight to the hydrophilic polyamide copolymer. More 1,2-propanediol may be used (e.g. 1.5 times the weight of copolymer), but may lengthen the drying time required in the application process. Less 1,2-propanediol may be used (e.g. 0.5 times the weight of copolymer), but reduces the solubility of the hydrophilic polyamide copolymer. The use of 1,2-propanediol is preferred over ethanol as taught in U.S. Pat. No. 4,468,505 because it is not flammable, it is less toxic, less carcinogenic, less of it may be used, and it has a higher boiling point and so is less fugitive.
Hydrophilic copolyesters are also useful hydrophilic agents in the present invention. Hydrophilic copolyesters include copolyesters containing both polyoxyethylene diester and alkylene diester segments. They may be simple copolyesters, i.e., they may contain only polyoxyethylene diester and polyalkylene diester segments, the copolyester being derived from a single polyethylene oxide, diester and glycol. Polyethylene oxides of various molecular weights, dimethyl terephthalate, and ethylene glycol are the most common raw materials for these copolymers, mainly because of cost and availability. Numerous variations on the comonomers used to prepare these simple hydrophilic copolyesters are possible. These copolymers are disclosed in U.S. Pat. No. 3,416,952, incorporated herein by reference in its entirety. Examples of these copolymers include “ZELCON” 5126 [CAS No. 9074-67-3], which is commercially available from Stepan Company, and “MILEASE” T [CAS No. 9016-88-0], which is commercially available from Imperial Chemical Industries, Limited, London, England. Both “ZELCON” 5126 and “MILEASE” T are sold in an aqueous dispersion form containing up to 85% water.
These permanent or semi-permanent hydrophilic treatment compositions previously described may be applied to the fabric or fiber by any suitable means such as wiping, painting, dipping, foaming, feeding at the nip of a roller, spraying, or other means. The composition is typically applied at a minimum level of at least 0.1% weight of solids on fiber, at least 0.5% weight of solids on fiber, to achieve water wicking and durability. Application at higher levels will improve hydrophilic character. After drying or removal of the solvent, a durable hydrophilic coating remains on the fabric or fiber surface. This coating causes water placed on the surface to rapidly wet the fabric and to move along the fiber length and through the fabric layer.
Other additives that may be applied on the fibers, for example, during spinning and/or drawing processes include antistatics, slickening agents, adhesion promoters, antioxidants, antimicrobials, flameproofing agents, lubricants, and combinations thereof. Moreover, such additional additives may be added during various steps of the process as is known in the art.
Filaments of the present invention having the five-legged zigzagged cross-section can be mixed with filaments of other cross-sections, e.g. circular cross-section, and/or polymers to form yarns. FIG. 5 is a microphotograph of a yarn comprising a plurality of filaments with the five-legged zigzagged cross section 110 and filaments with a larger dpf and varying cross section 120. The filaments 110 have indentations 80 along their longitudinal length which serve as channels to direct moisture.
The filaments of the present invention are formed by any suitable spinning method, which may vary based upon the type of polymer used. Generally, the melt-spinnable polymer is melted and the molten polymer is extruded through a spinneret capillary orifice having a design corresponding to the desired five-legged zigzagged cross-section of the present invention. The extruded fibers are then quenched or solidified with a suitable medium, such as air, to remove the heat from the fibers leaving the capillary orifice. After quenching, the filaments are converged, interlaced, and wound as a multifilament bundle.
The spinneret capillary used to produce the filaments of the present invention can be any suitable capillary capable of producing the five-legged zigzagged cross-section described above. One suitable spinneret capillary plate is represented in FIG. 2, which shows four rows of slot openings, with each row having five slots spaced apart from one another and angled in a zigzag configuration. The spinneret plate diagrammatically represented by FIG. 2 is capable of forming four (4) identical filaments of the five-legged zigzagged cross-sectional shape.
A single row of spinneret capillary slots is represented in FIG. 3. An angle θ formed by any pair of adjacent slot segments is between about 20° and 60° of arc. Moreover, referring to FIG. 3, the slot segments may have any length (L), for example, from about 0.130 mm to about 130 mm, for example between about 0.25 mm to about 0.50 mm, and any width (D), such as between about 0.025 mm to about 0.40 mm, for example about 0.075 mm to about 0.130 mm.
The spinneret capillaries, through which the molten polymer is extruded, represented by FIG. 3, are cut to produce the desired cross-section of the present invention. The capillaries or spinneret bore holes may be cut by any suitable method, such as by laser cutting, as described in U.S. Pat. No. 5,168,143, herein incorporated by reference, drilling, Electric Discharge Machining (EDM), and punching, as is known in the art. The capillary orifice is cut using a laser beam.
The dimensions for filaments of one embodiment are further defined with reference to a filament shown in FIG. 4. In FIG. 4, the width (A), the maximum thickness (B) and the minimum thickness (b) of the cross section of the spun filaments are represented. As shown in FIG. 4, the filament cross-section is shaped such that indentations 50 are disposed opposite each vertex. The maximum thickness (B) is measured as the distance between two sequential vertexes (such as 1 b and 2), while the minimum thickness (b) is measured as the distance between two sequential indentations 50. The indentation-to-thickness ratio (ITR) of the filament cross-section, which is important in determining the moisture wicking ability of the filament, is given by the equation ITR=1−b/B.
The filaments according to the invention have a cross-sectional width (A) ranging between about 28 and 42 microns, and for example between about 28 and 35 microns. For filaments having a denier per filament of about 3, the maximum thickness (B) is between about 12 and 15 microns, and the minimum thickness (b) is between about 5 and 10 microns. The spun filament has a ratio of A/B of less than 3, and an indentation to thickness ratio (ITR) of between about 0.25 and 0.60. For example, the ITR is between about 0.40 and 0.60, which indicates that the indentations 50 (FIG. 4) are deeper and will provide superior moisture movement along the length of the filament.
The filaments can be formed into any type of yarn, for example, fully drawn yarns or partially oriented yarn, as used, for example, in texturing feed yarns. Accordingly, in one embodiment, the filaments are spun as a fully drawn yarn, for example, a yarn having an orientation of about 35 to about 50% elongation to break, which may be immediately used in manufacturing fabrics and apparel articles. Optionally, however, the filaments of the present invention may be textured, also known as “bulked” or “crimped,” according to known methods. In an embodiment of the invention, the filaments may be drawn as a partially oriented yarn, for example, a yarn having an orientation of about 55 to about 75% elongation to break, and then textured by techniques, such as by draw false-twist texturing, air-jet texturing, gear-crimping, and the like.
The filaments of the invention can be processed into a multifilament fiber or yarn having any desired denier, filament count, and denier per filament (dpf). The yarn formed from the filaments of the present invention typically has a total denier between about 10 and about 300 denier, and for example, between about 20 and about 150 denier. The filaments of the present invention also typically have a denier per filament between about 0.1 to about 4 dpf, and for example, between about 0.9 to about 3.0. In one embodiment, the dpf is less than about 2.9, or less than about 2.5. The five-legged zigzagged cross-section filaments can be mixed with other filaments, for example, having a dpf above or below about 4.
The yarns of the present invention may further be formed from a plurality of different filaments having different dpf ranges. In such case, the yarns should be formed from at least one filament having the multilobal cross-section of the present invention. Each filament of a yarn containing a plurality of different filaments has the same or different dpf, and each dpf is between about 0.1 to about 4 dpf, and for example, between about 0.9 to about 3.0.
The filaments of the present invention may be used to make fabrics and garments. Any known suitable method of making fabrics and garments may be used. For example, wovens, warp knitting, circular knitting, hosiery knitting, and laying a staple product into a non-woven fabric are suitable for making fabrics and garments. In an embodiment, two-sided fabrics are made using the filaments of the present invention on primarily one side of the fabric. Any other type of yarn may be used to make up the other side of the fabric, and such other yarn has a different wicking ability. Suitable yarns for the other side of the two-sided fabric may be made up of polyamides, polyesters, polyolefins, and natural fibers, such as cotton, wool, silk, rayon, and combinations thereof. The two-sided fabrics may be made by methods known in the art. For example, the fabrics may be knitted using the multifilament yarn having five-legged zigzagged cross-sections of the present invention on one side and another yarn on the other side. Suitable methods of making the two-sided fabrics include warp knitting and plating the yarns. The two-sided fabrics have the benefit of allowing moisture to be drawn away from the body. Generally, the higher dpf fabric is used on the inside of a garment, and the lower dpf fabric is used on the outside of the garment. However, the five-legged zigzagged cross-section multifilament yarns of the present invention may be used on either side of the two-sided fabric. For example, the five-legged zigzagged cross-section multi-filament yarns of the present invention may be used on the outside of the fabric and treated with a finishing agent, such as a hydrophilic agent as described above. In another embodiment, a different yarn, such as cotton, may be used to form the outside of the fabric with the five-legged zigzagged multi-filament yarns on the inside.
In another embodiment, the yarn is formed from at least about 50%, for example at least about 80%, of the filaments of the present invention based on the total number of filaments, and such yarn is processed into a fabric or garment. In yet another embodiment, the yarn, fabric, or garment formed from the filaments of the present invention is combined with a permanent or semi-permanent hydrophilic wetting agent as described above. The fabrics are useful to make any type of apparel article, including swimwear, active wear, and ready-to-wear garments.
Any desired additional agent may be applied directly to the fabrics or garments. Examples of these additives include antistatics, antioxidants, antimicrobials, flameproofing agents, dyestuffs, light stabilizers, polymerization catalysts and auxiliaries, adhesion promoters, delustrants, such as titanium dioxide, matting agents, organic phosphates, permanent or semi-permanent hydrophilic wetting agent, and combinations thereof. For example, a suitable wetting agent is added to fabrics made using the multifilament yarns of the present invention. Suitable wetting agents for application directly to the fabric include hydrophilic agents, as described above.
The fabrics made using the filaments and yarns of the present invention have been found to exhibit excellent moisture wicking properties, soft hand, and silk-like high luster. The moisture wicking of the yarns of the invention is determined by known methods, such as by a vertical wicking test or a horizontal wicking test. The vertical wicking test may be conducted by knitting the yarns into tubes, and then either scouring or treating the tubes with any desired agent and allowing the treated tubes to air dry. The tubes are then cut into 1 inch (25.4) wide strips about 8 inches (203 mm) long and suspended vertically above water with 3 inches (75 mm) in the water and 5 inches (125 mm) above the water. Observations of the height of the water being wicked up the strips are conducted visually at predetermined times, such as at 1 minute, 5 minutes, 10 minutes, 20 minutes and 30 minutes.
The yarns of the present invention have a tenacity suitable for use in apparel. Tenacity is measured on an Instron equipped with two grips, which hold the yarns at the gauge lengths of 10 inches. The yarn is then pulled by the strain rate of 10 inch/minute, the data are recorded by a load cell, and stress-strain curves are obtained. Tenacity is the breaking strength (in grams) divided by the yarn's denier. Both partially oriented yarns and fully drawn yarns of the present invention can have a tenacity of between about 2 to about 8, for example between about 3 to about 6 grams per denier.
The elongation-to-break of the yarn can be measured using any known apparatus. For example, one method involves pulling to break on an Instron Tester TTB (Instron Engineering Corporation) with a Twister Head made by the Alfred Suter Company and using 1-inch×1-inch (25 mm×25 mm) flat-faced jaw clamps (Instron Engineering Corporation). Samples typically about 10-inches in length are subjected to two turns of twist per inch at a 60% per minute rate of extension at 65% Relative Humidity and 70° F. (21° C.). The elongation to break for both fully drawn yarns and partially oriented yarns of the present invention was between about 30% to about 80%, for example between about 40% to about 60%.
The boil off shrinkage of the yarn may be measured using any known method. For example, it may be measured by suspending a weight from a length of yarn to produce a 0.1 gram/denier load on the yarn and measuring its length (L₀). The weight is then removed and the yarn is immersed in boiling water for 30 minutes. The yarn is then removed, loaded again with the same weight, and its new length recorded (L_f). The percent shrinkage (S) is calculated by using the formula:
Shrinkage(%)=100(L ₀ −L _f)/L ₀
A low shrinkage is highly desirable for most textile purposes. The yarns of the present invention have a shrinkage less than about 10%, typically less than about 7%, for example less than about 6%.
The invention will now be illustrated by the following non-limiting examples.

EXAMPLES

Vertical Wicking Test

A sample of fabric is prepared with the following dimensions: 1 inch (25 mm) wide and 8 inches long. The sample is suspended vertically above water with three (3) inches (75 mm) of the fabric sample in the water and five (5) inches (125 mm) of the fabric sample above the water. The height of water wicking up the strip, up to five (5) inches (125 mm), is measured as a function of time. Observations are made at 1 minute, 5 minutes, 10 minutes, and 30 minutes. The test is stopped when the water wicking on the fabric is five (5) inches (125 mm).

Example A

An 80 denier-26 filaments five-legged, zigzagged cross-section yarn is spun at a temperature of 290° C. The yarn is spun from nylon 6,6, having a relative viscosity (RV) of between 45 and 47. The spinnerets are in a configuration of three ends per pack having the five-legged zigzagged cross-section. The nylon 6,6 is drawn at a draw ratio of 1.6× and spun at a windup speed of 5000-5200 meters per minute. Known spin and secondary spin finishes are used. The tenacity of the filaments is 3.7 grams per denier, and the yarn has an elongation to break of 42%. The yarn a cross-sectional shape is substantially that presented in FIG. 4. A photomicrograph of the yarn is shown in FIG. 5.
The yarn is combined with spandex (40 denier) in fabric. The fabric is circular knit, tricot knit or woven. Such fabric, when treated with a known hydrophilic finish exhibits vertical wicking behavior, which is superior to the comparative examples. A control nylon yarn is combined with spandex for comparison. The control yarn has a trilobal cross-setion.
While the invention has been described in connection with one or more embodiments, variations within the scope of the invention will likely occur to those skilled in the art. Thus, it is understood that the invention is covered by the following claims.

Claims

1. A synthetic polymer filament, comprising:

a cross-section that includes at least five contiguous segments in zigzag configuration, said cross-section having a nominal width, a nominal length and a nominal thickness.

2. The synthetic polymer filament of claim 1, wherein adjacent segments form an angle between about 40 degrees and about 60 degrees.

3. The synthetic polymer filament of claim 1, wherein the synthetic polymer filament comprises a polyamide synthetic polymer selected from the group consisting of: polyhexamethylene adipamide; polycaproamide; polyenanthamide; nylon 10; polydodecanolactam; polytetramethylene adipamide; polyhexamethylene sebacamide homopolymer; a polyamide of n-dodecanedioic acid and hexamethylenediamine homopolymer; and a polyamide of dodecamethylenediamine and n-dodecanedioic acid.

4. The synthetic polymer filament of claim 1, wherein a ratio of the nominal width to the nominal thickness is less than about 3.

5. The synthetic polymer filament of claim 1 having a denier per filament between about 0.1 and about 4.0.

6. The synthetic polymer filament of claim 1, having an indentation to thickness ratio between about 0.25 and 0.6.

7. A yarn formed at least in part from the synthetic polymer filament of claim 1.

8. The yarn of claim 7, wherein the yarn is formed from a number of filaments and the synthetic polymer filament of claim 1 comprises at least about 50% of the number of filaments in said yarn.

9. The yarn of claim 7 having a denier of between about 15 and about 200.

10. A fabric formed at least in part from the yarn of claim 7.

11. A garment formed at least in part of the fabric of claim 10.

12. A fabric formed at least in part from the synthetic polymer filament of claim 1.

13. The fabric of claim 12, wherein said fabric is a double sided fabric comprising the synthetic polymer filament of claim 1 on one side of the fabric.

14. The fabric of claim 13, wherein a wetting agent is applied to the one side.

15. The fabric of claim 14, wherein said wetting agent is selected from the group consisting of a hydrophilic polyamide, hydrophilic silicone, and hydrophilic polyester.

16. A synthetic polymer filament, comprising:

a cross-section that includes five contiguous segments in zigzag configuration, wherein each segment defines a proximal end and a distal end, wherein a distal end of a first segment is connected to a proximal end of a second segment, wherein a distal end of the second segment is connected to a proximal end of a third segment, wherein a distal end of the third segment is connected to a proximal end of a fourth segment, wherein a distal end of the fourth segment is connected to a proximal end of a fifth segment, and wherein a pivot point is defined along the fourth segment and the cross-section of the filament is symmetrical when rotated 180 degrees about said pivot point.

17. The synthetic polymer filament of claim 16, wherein adjacent segments form an angle between about 40 degrees and about 60 degrees.

18. The synthetic polymer filament of claim 16, wherein the synthetic polymer filament comprises a polyamide synthetic polymer selected from the group consisting of: polyhexamethylene adipamide; polycaproamide; polyenanthamide; nylon 10; polydodecanolactam; polytetramethylene adipamide; polyhexamethylene sebacamide homopolymer; a polyamide of n-dodecanedioic acid and hexamethylenediamine homopolymer; and a polyamide of dodecamethylenediamine and n-dodecanedioic acid.

19. The synthetic polymer filament of claim 16 having a denier per filament of about 1.0 to about 4.0.

20. The synthetic polymer filament of claim 16 having an indentation-to-thickness ratio between about 0.25 and about 0.6.

21. A yarn formed at least in part from the synthetic polymer filament of claim 16.

22. The yarn of claim 21, wherein the yarn is formed from a number of filaments and the synthetic polymer filament of claim 16 comprises at least about 50% of the total number of filaments in said yarn.

23. The yarn of claim 20 having a denier of between about 16 and about 200.

24. Fabric formed at least in part from the yarn of claim 21.

25. Garment formed from at least in part from the fabric of claim 24.

26. The fabric of claim 24, wherein said fabric is a double sided fabric comprising the synthetic polymer filament of claim 16 on one side of the fabric.

27. The fabric of claim 26, wherein a wetting agent is applied to the one side.

28. The fabric of claim 26, wherein said wetting agent is selected from the group consisting of a hydrophilic polyamide, hydrophilic silicone, and hydrophilic polyester.

29. A synthetic polymer filament, comprising:

a cross-section having multiple segments arranged in a five-legged zigzagged shape including an upright W-shaped portion with an additional leg added to the W shape.