WO2011056467A2

WO2011056467A2 - Nylon -- cotton fabric having high durability and breathability

Info

Publication number: WO2011056467A2
Application number: PCT/US2010/053729
Authority: WO
Inventors: Osman Mohammad; Martin Townson
Original assignee: Invista Technologies S.A.R.L.
Priority date: 2009-10-28
Filing date: 2010-10-22
Publication date: 2011-05-12
Also published as: WO2011056467A3

Abstract

Included are light weight NYCO fabrics having high durability and breathability made from nylon staple fibers having a denier per filament of about 1.0 to 3.0, a tenacity T at break of at least about 6.0, and a load-bearing capacity, T₇, of greater than about 2.5, including greater than 3.2. Such nylon staple fibers may be produced by preparing tows of nylon filaments, drawing and annealing such tows via a multi-stage drawing and annealing operation and then cutting or otherwise converting the drawn and annealed tows into the desired high strength nylon staple fibers.

Description

NYLON - COTTON FABRIC HAVING HIGH

DURABILITY AND BREATHABILITY

Cross-Reference to Related Application

[0001] This application claims priority to U.S. Provisional Application No. 61/255,700, filed on October 28, 2009, which is entirely incorporated herein by reference.

Field of the Invention

[0002] The invention relates to a nylon-blend fabrics such as nylon- cotton (hereinafter "NYCO") light weight fabric that has improved durability and breathability over traditional NYCO fabrics. Such fabric can be produced by using a nylon fiber having a tenacity of at least about 6 grams per denier, and a load bearing capacity of at least about 2.5 grams per denier measured as tenacity at 7% elongation (hereinafter "T₇"). A polyamide filament, such as nylon 6,6, can be inserted into the fabric to improve durability, such as tear strength. Tensile, tear strength, and abrasion resistance are improved, while breathability is increased and weight is decreased. Applications for such fabric include, for example, military apparel such as combat uniforms or other rugged use apparel.

Background of the Related Technology

[0003] Temperate combat uniforms are manufactured from polyester-cotton blends. As conflicts have moved to desert environments, new lighter weight, more air permeable polyester- cotton uniforms have been developed and introduced. Such uniforms, however, do not have the necessary durability levels for desert conditions. For example, existing fabrics use 300-400 decitex yarns that result in a weight of 200 - 250 grams / meter². This fabric may be too heavy and dense for some military applications. On the opposite end, Seafield Textiles in Ireland uses 300-400 decitex yams in a more open construction that results in a sub 200 grams / meter² fabric. This fabric, however, has shown poor abrasion resistance. [0004] U.S. Patent Publication No. 2006/0183390 discloses a lightweight, permeable polyamide fabric with high tear strength for use in bedding or furniture covers. Tear strength is achieved by weaving the fabric with a particular rip stop texture. U.S. Patent Publication No. 2002/1224904 discloses a puncture resistant fabric comprising woven fabrics with unique, densely woven structures. U.S. Patent Application No. 5,759,207 discloses a flat duck cotton-thermoplastic fiber blend fabric for use in obtaining low laundry shrinkage apparel. A flat duck fabric is a compact, firm, heavy and plain weave fabric with a warp of two single yarns woven as one and a filing of either single or plied yarn. Such fabric is commonly worn by welders.

Summary of the Invention

[0005] The prior NYCO fabrics are deficient in that there is no lightweight NYCO fabric that yields high durability and breathability. Prior NYCO fabrics have generally proven satisfactory for military or other rugged apparel use, however, military personnel are continually looking for improved fabrics that may be abrasion resistant, breathable, higher in strength, lighter in weight, lower in cost and/or more comfortable but still highly durable or even of improved durability. Therefore, a lightweight, high durability and breathable fabric for military use, or similar rugged applications, is needed.

[0006] One approach to such NYCO fabrics of improved abrasion resistance, durability, breathability, and weight could involve preparation of NYCO fabrics, wherein the nylon staple fibers used in the fabric have high load bearing capacity, which would result in improved abrasion resistance and durability in comparison with fabrics currently used. Such nylon staple fibers can have a tenacity at break (T) of at least about 6 grams per denier, and a load bearing capacity (T₇) of at least about 2.5 grams per denier. Another approach to achieving increased durability is to incorporate a polyamide fiber in filament form, such as nylon 6,6, into the NYCO fabric, thereby improving tear strength. Such filaments may be woven into a fabric which is otherwise comprised of yarns of blended staple fibers such as such as nylon-cotton staple.

[0007] Nylon staple fibers can be produced in a variety of ways. For example, Thompson in U.S. Patent Nos. 5,093,195 and 5,01 1 ,645 discloses nylon staple fiber preparation wherein nylon 6,6 polymer, having for example a formic acid relative viscosity (RV) of 55, is spun into filaments which are then drawn, annealed, cooled and cut into staple fiber having a tenacity at break, T, of about 6.8-6.9, and a load- bearing capacity, T₇, of from about 2.75 to 3.2. (Both of these Thompson patents are incorporated herein by reference in their entirety.).

[0008] Given the foregoing considerations, some aspects are directed to a lightweight NYCO fabric having high durability and breathability. The resulting NYCO fabrics can be woven from textile yarns in both a warp and weft (fill) direction wherein said textile yarns woven in at least one direction comprise blended yarns including nylon staple such as blended yarns including nylon staple fibers blended with cotton staple fibers in a weight ratio of cotton staple fibers to nylon staple fibers ranging from 20:80 to 80:20; and wherein said nylon staple fibers have a denier per filament of from about 1.0 to about 3.0, a tenacity of at least 6.0 grams per denier, and a load-bearing capacity of greater than 2.5 grams per denier, including greater than 3.2 grams per denier up to about 5.0 grams per denier or greater, measured as tenacity (T₇) at 7% elongation, wherein said fabric further comprises at least one filament, fiber or yarn that provides increased tear strength such as textured nylon filament, non-textured nylon filament (i.e., flat nylon filament), textured polyester filament, or non-textured polyester filament, among others in either the warp direction, weft direction, or both.

[0009] In another aspect, a light weight NYCO fabric having high durability and breathability is disclosed. The resulting NYCO fabrics can be woven from textile yarns in both a warp and weft (fill) direction wherein said textile yarns woven in both directions comprise blended yarns including nylon staple such as blended yarns including nylon staple fibers blended with cotton staple fibers in a weight ratio of cotton staple fibers to nylon staple fibers ranging from 20:80 to 80:20; and further characterized in that the yarns woven in the weft (fill) direction comprise nylon staple fibers having a denier per filament of from .3 to 2.0 and the yarns woven in the warp direction comprise nylon staple fibers having a denier per filament of from 2.5 to 3.0, wherein said fabric further comprises at least one fiber or yarn that provides increased tear strength such as textured nylon filament, non-textured nylon filament (i.e., flat nylon filament), textured polyester filament, or non-textured polyester filament, among others in either the warp direction, weft direction, or both.

[00010] In yet another aspect, a light weight NYCO fabric having high durability and breathability is disclosed. The resulting NYCO fabrics can be woven from textile yarns in both a warp and weft (fill) direction wherein said textile yams woven in at least one direction comprise blended yarns including nylon staple such as blended yarns including nylon staple fibers blended with cotton staple fibers in a weight ratio of cotton staple fibers to nylon staple fibers ranging from about 20:80 to 80:20; and further characterized in that said nylon staple fibers are made from nylon having a formic acid relative viscosity (RV) of from 45 to 100, said nylon fibers further having a denier per filament of from 1.0 to 3.0, a tenacity of at least 6.0 grams per denier and a load-bearing capacity of greater than 2.5, grams per denier, including greater than 3.2 grams per denier, up to 5.0 or greater, measured as tenacity (T₇) at 7% elongation, wherein said fabric further comprises at least one fiber or yarn that provides increased tear strength such as textured nylon filament, non-textured nylon filament (i.e., flat nylon filament), textured polyester filament, or non-textured polyester filament, among others in either the warp direction, weft direction, or both.

[00011] In the resulting NYCO fabrics, the yarns used in the warp and weft directions, respectively, may be differentiated by other physical properties or performance specifications. For example, a fabric may be constructed with yarns in the warp direction that have relatively higher abrasion resistance, but lower tensile strength, as compared to yarns used in the weft direction.

Brief Description of the Drawings

[00012] FIGs 1A and 1 B illustrate the weave pattern of Fabric 1 showing a light weight NYCO fabric in a 2/2 twill pattern with 2 picks of textured nylon 6,6 filament.

[00013] FIGs 2A and 2B illustrate the weave pattern of Fabric 2 showing a light weight NYCO fabric in a plain rip stop 3/3 warp / weft weave with a weft nylon 6,6 filament weave pattern.

[00014] FIGs 3A and 3B illustrate the weave pattern of Fabric 3 showing a light weight NYCO fabric with a square center rib/weft direction textured nylon 6,6 filament weave pattern.

[00015] FIGs 4A and 4B illustrate the weave pattern of Fabric 4 showing a light weight NYCO fabric with a weft direction textured nylon

6,6 filament weave pattern.

[00016] FIGs 5A and 5B illustrate the weave pattern of Fabric 5 showing a light weight, true ripstop NYCO fabric with a warp and weft direction textured nylon 6,6 filament weave pattern.

[00017] FIGs 6A and 6B illustrate the weave pattern Fabric 6, a heavy weight, true ripstop NYCO fabric with a warp and weft direction textured nylon 6,6 filament weave pattern.

[00018] FIGs 7A and 7B illustrate the weave pattern of Fabric 7, a heavy weight, true ripstop NYCO fabric with a warp and weft direction textured nylon 6,6, filament weave pattern.

[00019] FIGs 8A and 8B illustrate the weave pattern of Fabric 8, a heavy weight, 2/2 twill NYCO fabric with a warp and weft direction textured nylon 6,6, filament weave pattern.

[00020] FIGs 9A and 9B illustrate the weave pattern of Fabric 9, a heavy weight, 2/2 twill NYCO fabric with 2 pick weft direction textured nylon 6,6, filament weave pattern. Detailed Description of the Invention

[00021] As used herein, the terms "durable" and "durability" refer to the propensity of a fabric so characterized to have suitably high grab and tear strength as well as resistance to abrasion for the intended end use of such fabric, and to retain such desirable properties for an appropriate length of time after fabric use has begun.

[00022] As used herein, the term blend or blended, in referring to a spun yarn, means a mixture of fibers of at least two types, wherein the mixture is formed in such a way that the individual fibers of each type of fiber are substantially completely intermixed with individual fibers of the other types to provide a substantially homogeneous mixture of fibers, having sufficient entanglement to maintain its integrity in further processing and use.

[00023] As used herein, cotton count refers to the yarn numbering system based on a length of 840 yards, and wherein the count of the yarn is equal to the number of 840-yard skeins required to weigh 1 pound.

[00024] As used herein, the at least one fiber or yarn that provides increased tear strength can include flat nylon filament, textured nylon filament, non-textured nylon filament (i.e., flat nylon filament), textured polyester filament, or non-textured polyester filament, among others. Wherever the term "textured nylon filament" is used, it is understood that it can be replaced by another suitable filament yarn.

[00025] Some aspects are based on the preparation of improved NYCO fabrics having certain specified characteristics woven from certain nylon and cotton yarns. The nylon and cotton yarns can also be blended with at least one other fiber, also referred to as a companion fiber; alternatively, the cotton fibers can be partially or fully replaced by one or more companion fibers, depending on the desired characteristics of the fabric. In other words, the term NYCO as used herein may also include another nylon blended yarn. The other fibers may be one or more fibers selected from the group consisting of cellulosics such as cotton or rayon, modified cellulosics such as FR rayon or FR-treated cellulose, animal fibers such as wool, polyester, fire resistant (FR) polyester, FR nylon, m-aramid, p-aramid, modacrylic, novoloid, melamine, polyvinyl chloride, antistatic fiber, PBO (1 ,4- benzenedicarboxylic acid, polymer with 4,6-diamino-1 , 3- benzenediol dihydrochloride), PBI (polybenzimidazole), and combinations thereof. The nylon staple fibers can also provide an increase in strength and/or abrasion resistance to yarns and fabrics. This is especially true for combination with relatively weaker fibers such as cotton and wool. Each of these said other fibers listed hereinabove in this paragraph can also be included as a companion yarn, in addition to the NYCO yarn in any of the fabrics disclosed herein.

[00026] The specific characteristics of the nylon staple fibers prepared and used herein include formic acid RV of the nylon used to make the fiber, fiber denier, fiber tenacity and fiber load-bearing capacity defined in terms of fiber tenacity at 7% elongation.

[00027] Realization of the desired nylon staple fiber material herein is also based on the use of staple fiber manufactured from nylon polymeric material having certain selected properties. The nylon polymer itself which is used for the spinning of nylon filaments can be produced in conventional manner. Nylon polymer suitable for use in the process and filaments of this invention consists of synthetic melt spinnable or melt spun polymer. Such nylon polymers can include polyamide homopolymers, copolymers, and mixtures thereof which are predominantly aliphatic, i.e., less than 85% of the amide-linkages of the polymer are attached to two aromatic rings. Widely-used polyamide polymers such as poly(hexamethylene adipamide) which is nylon 6,6 and poly(E-caproamide) which is nylon 6 and their copolymers and mixtures can be used in accordance with some aspects of the disclosed NYCO fabric. Other polyamide polymers which may be advantageously used are nylon 12, nylon 4,6, nylon 6,10, nylon 6,12, nylon 12,12, and their copolymers and mixtures. Illustrative of polyamides and copolyamides which can be employed in the process, fibers, yarns and fabrics of this invention are those described in U.S. Patent Nos. 5,077,124, 5,106,946, and 5,139,729 (each to Cofer et al.) and the polyamide polymer mixtures disclosed by Gutmann in Chemical Fibers International, pages 418-420, Volume 46, December 1996. These publications are all incorporated herein by reference. Further, nylons or polyamides include poly(hexamethylene adipamide) (nylon 6,6); polycaprolactam (nylon 6); polyenanthamide (nylon 7); nylon 10; poly(12-dodecanolactam) (nylon 12); polytetramethylene- adipamide (nylon 4,6); polyhexamethylene sebacamide (nylon 6,10); poly(hexamethylene dodecanamide) (nylon 6,12); the polyamide of dodecamethylenediamine and n-dodecanedioic acid (nylon 12,12), PACM-12 polyamide derived from bis(4-aminocyclohexyl)methane and dodecanedioic acid, the copolyamide of 30% hexamethylene diammonium isophthalate and 70% hexamethylene diammonium adipate, the copolyamide of up to 30% bis-(P-amidocyclo- hexyl)methylene, and terephthalic acid and caprolactam, poly(4- aminobutyric acid) (nylon 4), poly(8-aminooctanoic acid) (nylon 8), poly(hapta-methylene pimelamide) (nylon 7,7), poly(octamethylene suberamide) (nylon 8,8), poly(nonamethylene azelamide) (nylon 9,9), poly(decamethylene azelamide) (nylon 10,9), poly(decamethylene sebacamide(nylon 10,10), poly[bis(4-amino-cyclohexyl)methane-1 ,10- decanedicarboxamide], poly(m-xylene adipamide), poly(p-xylene sebacamide), poly(2,2,2-trimethylhexamethylene pimelamide), poly(piperazine sebacamide), poly(1 1-amino-undecanoic acid) (nylon 11 ), polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, and poly(9-aminononanoic acid) (nylon 9) polycaproamide. Copolyamides can also be used.

[00028] The fabric weave patters illustrated in FIGs 1-5 will be described in more detail.

[00029] FIGs 1A and 1 B disclose a light weight, durable, and breathable NYCO fabric (Fabric 1 ) having a warp cover factor of from about 10 to about 30, and preferably about 20.5, a weft cover factor of from about 7 to about 15, including about 12.2, and a total fabric cover factor of from about 17 to about 45, including about 32.7. The weft yarn further comprises a polyamide textured filament with a decitex of from about 50 to about 440, including about 240; and filaments per yarn from about 30 to about 140, including about 68. The polyamide textured filament can be nylon 6,6. The resulting NYCO fabric has a design pattern that can be characterized as 2/2 twill with 2 picks of polyamide filament, with a fabric weight of from about 160 g/m² to about 190 g/m², including about 175 g/m²; and a finished thread count per centimeter of from about 40 to 50 ends, and from about 5 to 35 picks, including about 40-42 ends and about 25 picks.

[00030] FIGs 2A and 2B disclose a lightweight NYCO fabric (Fabric

2) having high durability and breathability. The resulting NYCO fabric has a warp cover factor of from about 10 to about 30, and preferably about 20.5, a weft cover factor of from about 7 to about 15, including about 12.2, and a total fabric cover factor of from about 17 to about 45, including about 32.7. The weft yarn further comprises a polyamide textured filament with a decitex of from about 50 to about 440, including about 240; and filaments per yarn from about 30 to about 140, including about 68. The polyamide textured filament can be nylon 6,6. The resulting NYCO fabric has a design pattern that can be characterized as 3/3 warp and weft rip-stop, with a fabric weight of from about 160 g/m² to about 190 g/m², including about 175 g/m²; and a finished thread count per centimeter of from about 40 to 50 ends, and from about 15 to 35 picks, including about 40-42 ends and about 25 picks.

[00031] FIGs 3A and 3B disclose a lightweight NYCO fabric (Fabric

3) having high durability and breathability. The resulting NYCO fabric has a warp cover factor of from about 10 to about 30, including about 20.5, a weft cover factor of from about 7 to about 15, including about 12.2, and a total fabric cover factor of from about 7 to about 45, including about 32.7. The weft yarn further comprises a polyamide textured filament with a decitex of from about 50 to about 440, including about 240; and filaments per yarn from about 30 to about 140, including about 68. The polyamide textured filament can be nylon 6,6. The resulting NYCO fabric has a design pattern that can be characterized as a rip stop fabric with square center rib with a weft direction polyamide, textured filament, with a fabric weight of from about 160 g/m² to about 190 g/m², including about 175 g/m²; and a finished thread count per centimeter of from about 40 to 50 ends, and from about 15 to 35 picks, including about 40-42 ends and about 25 picks.

[00032] FIGs 4A and 4B disclose a lightweight NYCO fabric (Fabric

4) having high durability and breathability. The resulting NYCO fabric has a warp cover factor of from about 10 to about 30, including about 20.5, a weft cover factor of from about 7 to about 15, including about 12.2, and a total fabric cover factor of from about 17 to about 45, including about 32.7. The weft yarn further comprises a polyamide textured filament with a decitex of from about 50 to about 440, including about 240; and filaments per yarn from about 30 to about 140, including about 68. The polyamide textured filament can be nylon 6,6. The resulting NYCO fabric has a design pattern that can be characterized rip stop fabric with a weft direction polyamide, textured filament, with a fabric weight of from about 160 g/m² to about 190 g/m², including about 175 g/m²; and a finished thread count per centimeter of from about 40 to 50 ends, and from about 15 to 35 picks, including about 40-42 ends and about 25 picks.

[00033] FIGs 5A and 5B disclose a lightweight NYCO fabric (Fabric

5) having high durability and breathability. The resulting NYCO fabric has a warp cover factor of from about 10 to about 30, including about 20.5, a weft cover factor of from about 7 to about 15, including about 12.2, and a total fabric cover factor of from about 17 to about 45, including about 32.7. The weft and warp yams further comprise a polyamide textured filament with a decitex of from about 50 to about 440, including about 240; and filaments per yarn from about 30 to about 140, including about 68. The polyamide, textured filament can be nylon 6,6. The resulting NYCO fabric has a design pattern that can be characterized as a rip stop fabric with warp and weft direction polyamide, textured filament, with a fabric weight of from about 160 g/m² to about 190 g/m², including about 175 g/m²; and a finished thread count per centimeter of from about 40 to 50 ends, and from about 15 to 35 picks, including about 40-42 ends and about 25 picks. [00034] The resulting NYCO fabrics comprise both cotton staple fibers and nylon staple fibers in a weight ratio of cotton to nylon fibers that ranges from about 20:80 to 80:20, including about 48:52. The warp yarn has a cotton count of from about 10 to about 80, including about 25. The weft yarn has a cotton count of from about 10 to about 80, including about 25. The warp and weft yarns are one ply or multiple plies. The nylon polymer staple fibers in the NYCO fabric can comprise nylon polymer having a formic acid RV of from 45 to 100, including from 55 to 100, from 46 to 65; from 50 to 60; and from 65 to 100, which have a denier per filament of from 1.0 to 3.0, a tenacity of at least 6.0 grams per denier and a load bearing capacity of greater than 2.5, including greater than 3.2 grams per denier, measured at T₇. Alternatively, in such fabrics the NYCO yarns woven in the weft direction can comprise nylon staple fibers having a denier per filament of from about 1.3 to about 2.0, including from about 1.55 to about 1.8, from about 1.6 to about 1.8, and from about 1.55 to about 1.75, and the NYCO yarns woven in the warp direction comprise nylon staple fibers having a denier per filament of from about 2.5 to about 3.0, including from about 2.3 to about 2.7. Further, the NYCO yams woven in the weft or warp direction can have a tenacity of greater than 6.0 grams per denier and a load bearing capacity of from greater than about 2.5 including greater than 3.2 grams per denier, measured at T₇. This can result in a NYCO fabric having a 5 to 7 times increase in abrasion resistance over existing NYCO fabrics, while still maintaining light weight and high breathability.

[00035] The nylon used in the disclosed NYCO fabrics can be prepared in a variety of ways as is known in the prior art. Nylon polymer used in the preparation of nylon staple fibers has conventionally been prepared by reacting appropriate monomers, catalysts, antioxidants and other additives, such as plasticizers, delustrants, pigments, dyes, light stabilizers, heat stabilizers, antistatic agents for reducing static, additives for modifying dye ability, agents for modifying surface tension, etc. Polymerization has typically been carried out in a continuous polymerizer or batch autoclave. The molten polymer produced thereby has then typically been introduced to a spin pack wherein it is forced through a suitable spinneret and formed into filaments which are quenched and then formed into tows for ultimate processing into nylon staple fiber. As used herein, spin pack is comprised of a pack lid at the top of the pack, a spinneret plate at the bottom of the pack and a polymer filter holder sandwiched between the former two components. The filter holder has a central recess therein. The lid and the recess in the filter holder cooperate to define an enclosed pocket in which a polymer filter medium, such as sand, is received. There are provided channels interior to the pack to allow the flow of molten polymer, supplied by a pump or extruder to travel through the pack and ultimately through the spinneret plate. The spinneret plate has an array of small, precision bores extending there through which convey the polymer to the lower surface of the pack. The mouths of the bores form an array of orifices on the lower surface of the spinneret plate, which surface defines the top of the quench zone. The polymer exiting these orifices is in the form of filaments which are then directed downwards through the quench zone.

[00036] The extent of polymerization carried out in the continuous polymerizer or batch autoclave can generally be quantified by means of a parameter known as relative viscosity or RV. RV is the ratio of the viscosity of a solution of nylon polymer in a formic acid solvent to the viscosity of the formic acid solvent itself. Determination of RV is described in greater detail in the Test Methods section hereinafter. RV is taken as an indirect indication of nylon polymer molecular weight. For purposes herein, increasing nylon polymer RV is considered synonymous with increasing nylon polymer molecular weight.

[00037] One method for preparing nylon staple fibers having high load bearing capacity, for example about 2-5 -3.2 grams per denier T₇, useful in producing the inventive fabrics disclosed herein is the process described by Thompson in U.S. Patent No. 5,093,195 and U.S. Patent No. 5,01 1 ,645. In accordance with this process, multiplicity of melt spun and subsequently quenched nylon filaments are arranged into a tow which is first cold drawn between a set of feed rolls and a set of draw rolls, followed by annealing the resulting drawn tow by heating it to a temperature of about 145°C to about 200°C, and then cooling it to less than about 80°C while maintaining the drawn tow under a controlled tension throughout both said heating and said cooling steps as the tow is advanced by a further set of rolls.

[00038] As nylon molecular weight increases, its processing becomes more difficult due to the increasing viscosity of the nylon polymer. Accordingly, continuous polymerizers or batch autoclaves are typically operated to provide nylon polymer for eventual processing into staple fiber wherein the nylon polymer has an RV value of about 60 or less.

[00039] High molecular weight nylon polymer, i.e., nylon polymer having RV values of greater than 70-75 and up to 140 or even 190 and higher can be advantageous. High RV nylon polymer of this type has improved resistance to flex abrasion and chemical degradation. Accordingly, such high RV nylon polymer is especially suitable for spinning into nylon staple fiber which can advantageously be used for the preparation of papermaking felts. Procedures and apparatus for making high RV nylon polymer and staple fiber therefrom are disclosed in U.S. Patent No. 5,236,652 to Kidder and in U.S. Patent Nos. 6,235,390, 6,605,694, 6,627,129 and 6,814,939 to Schwinn and West. All of these patents are incorporated herein by reference in their entirety.

[00040] In accordance with one embodiment of a method for preparing staple fiber that can exhibit both increased load bearing capacity, for example greater than 2.5 grams per denier, including greater than 3.2 grams per denier T₇, and improved abrasion resistance, nylon polymer which is melt spun into tow-forming filaments through one or more spin pack spinnerets and quenched will have an RV value ranging from 45 to 00, including from 55 to 100, from 46 to 65; from 50 to 60; and from 65 to 100. Nylon polymer of such RV characteristics can be prepared, for example, using a melt blending of polyamide concentrate procedure such as the process disclosed in the aforementioned Kidder '652 patent. Kidder discloses certain embodiments in which the additive incorporated into the polyamide concentrate is a catalyst for the purpose of increasing the formic acid relative viscosity (RV). Higher RV nylon polymer available for melting and spinning, such as nylon having an RV of from 65 to 100, can also be provided by means of a solid phase polymerization (SPP) step wherein nylon polymer flakes or granules are conditioned to increase RV to the desired extent. Such solid phase polymerization (SPP) procedures are well-known and disclosed in greater detail in the aforementioned Schwinn/West '390, '694, "129 and '939 patents.

[00041] Nylon polymer material prepared as hereinbefore described and having the desired RV characteristics may be fed to a spin pack, for example via a twin screw melter device. In the spin pack the nylon polymer is spun by extrusion through one or more spinnerets into a multiplicity of filaments. For purposes herein, the term "filament" is defined as a relatively flexible, macroscopically homogeneous body having a high ratio of length to width across its cross-sectional area perpendicular to its length. The filament cross section can be any shape, but is typically circular.

[00042] Each individual spinneret position may contain from 100 to 1950 filaments in an area as small as 9 inches by 7 inches (22.9 cm x 17.8 cm). Spin pack machines may contain from one to 96 positions, each of which provides bundles of filaments which eventually get combined into a single tow band for drawing/downstream processing with other tow bands.

[00043] After exiting the spinneret(s) of the spin pack, the molten filaments which have been extruded through each spinneret are typically passed through a quench zone wherein a variety of quenching conditions and configurations can be used to solidify the molten polymer filaments and render them suitable for collection together into tows. Quenching is most commonly carried out by passing a cooling gas, e.g., air, toward, onto, with, around and through the bundles of filaments being extruded into the quenching zone from each spinneret position within the spin pack. [00044] One suitable quenching configuration is cross-flow quenching wherein the cooling gas such as air is forced into the quenching zone in a direction which is substantially perpendicular to the direction that the extruded filaments are travelling through the quench zone. Cross-flow quenching arrangements are described, among other quenching configurations, in U.S. Patent Nos. 3,022,539, 3,070,839, 3,336,634, 5,824,248, 6,090,485, 6,881 ,047 and 6,926,854, all of which patents are incorporated herein by reference.

[00045] In a staple fiber preparation process discussed herein, the extruded nylon filaments used to eventually form the desired nylon staple fibers should be spun, quenched and formed into tows with both positional uniformity and uniformity of quenching conditions which are sufficient to permit use of draw ratios that provide an eventual staple fiber T₇ tenacity greater than 2.5 grams per denier or, under certain conditions, even greater than 3.2 grams per denier. Positional uniformity includes both within-position uniformity and position-to- position uniformity, and becomes more critical the higher the desired draw ratio and associated T₇.

[00046] Both types of positional uniformity can be improved by carefully controlling temperature of the nylon polymer fed to the spin pack, as opposed to simply monitoring temperature of the heat exchange medium used to heat the polymer supply lines and pack wells. U.S. Patent No. 5,866,050, incorporated herein by reference, discloses a method to better control nylon polymer temperature and refers to the importance of having a uniform polymer temperature. The specific method disclosed in order to achieve this result involves a first temperature control arrangement for heating the spin pack to a first predetermined reference temperature greater than the predetermined polymer inlet temperature such that the temperature across a polymer filter holder and the spinneret plate in the spin pack is substantially uniform. A plate assembly having at least one polymer flow passage therein is disposed between the outlet of the pump and the inlet of the spin pack. A second temperature control arrangement for independently controlling the temperature of the plate assembly to a second predetermined reference temperature is provided.

[00047] Remelting of the polymer, e.g., in a twin screw melter, rather than feeding polymer from a continuous polymerization (CP) operation, can also help provide polymer to the spin pack and quench chimney(s) at a uniform controlled temperature. A twin screw melter has the ability to measure and control polymer temperature at various position-to- position locations prior to delivery to the spinneret versus a continuous polymerization unit which only measures heat exchange medium temperature at similar locations prior to the spinneret/pack. Polymer made from a continuous polymerizer also is known to contain gel which is degraded or cross-linked polymer. Gel can cause downstream drawing issues in terms of broken filaments. It is well known that use of a twin screw melter has been found to reduce the amount of gel versus a polymer supply from a CP unit. This is an example of features of the polymer supply which enable the extruded filaments to be made more uniformly and drawn at higher ratios.

[00048] Spin center position-to-position filament bundle uniformity can also affect downstream draw processing. Sources of position-to- position filament bundle uniformity problems start with the machine and quench medium design. Use of fewer spin positions can facilitate improvements in position-to-position uniformity. Spin machines having 20 or fewer spinneret positions are easier to control with respect to maintenance of constant quench medium pressure along the length of the spin machine duct work, versus for example, 40 or even 96 positions. Fewer positions coupled with having the quench medium duct work reduced in length by approximately 50% from conventional practice allows for provision of a more uniform, non-turbulent quench medium supply to the spin center.

[00049] Another design feature of the spin center which facilitates uniform filament production relates to the quench medium filtering system. An improved quench air filter system, upstream of the spin center, continually monitors the pressure drop across the filters to control post filter air flow and pressure. Air flow and pressure are functions of the product spun.

[00050] Other design features of the spin center which can provide improved position-to-position filament uniformity is to have the pack spinneret positioned exactly in the center of the quench chimney. All of these design features improve the position-to-position uniformity of the product being spun on the machine and contribute to improvements in the downstream drawing performance of tows formed from the filaments which are spun and quenched.

[00051] Within-position filament uniformity has the largest effect on downstream processing of tows and on obtaining the desired resulting staple fiber properties. Numerous prior art references discuss the problems encountered in obtaining filaments with uniform properties made at higher throughputs and using high filament density melt spinning processes. U.S. Patent No. 4,248,581 mentions the quenching of filaments in a uniform manner and the difficulties associated with cross-flow quench. These same issues are also discussed in the '539, '839, '634, '248; '485, Ό47 and '854 patents hereinbefore referenced. Overcoming such within-position problems associated with uniformity of quenching conditions within the quenching zone is an important factor in permitting utilization of generally higher draw ratios in the subsequent drawing/annealing stage of the process herein.

[00052] In some cross-flow quenching operations, quench air is forced through the molten polymer filament bundles from one side of a rectangular filament array. Issues which can arise from this type of filament quenching are that the rows of filaments closest to the air flow quench first or quicker while the rows of filaments further from the air flow quench at a later time. It is also well-known that the quench air gets pulled with the filaments' downward movement and heated as it moves through the filament array or bundle. This contributes to uneven quenching of the molten filaments. Such uneven, non uniform quench can cause crystallization differences between the front, middle and back filaments. If this crystallization difference is large enough, it can cause fibers in the filament bundles to draw more or less. In other words, those filaments fully quenched early in the quench chimney versus later may not draw to the same ratio. This, in turn, can lead to excessive filament breaks when the tows formed from such nonuniform filaments are drawn at higher draw ratios or can limit the draw ratio that can be used due to inoperability of the draw machine.

[00053] As noted in the publication Ziabicki; "Fundamentals of Fibre Formation", (J Wiley &Sons), 1976, p196 ff and p 241 , the cooling conditions directly below the nozzle package are decisive for the thread quality. Ziabicki further points out that in the case of cross-flow quench, velocity measurements indicate that the bundle of threads exerts a considerable resistance to the quench air flow. Thus, the velocity of the air past the bundle is considerably reduced. This effect may stem from the fact that the blow air flows around the bundle instead of flowing through the same. Ziabicki also discloses that even more dramatic effects are observed in temperature distribution. The differences in air temperature measured before and beyond the bundle as well inside the bundle, can be substantial. He cites another study in which the structure and mechanical properties of filaments taken from various parts of the bundle were related to the range of air temperature in the individual parts of the bundle. Ziabicki concludes that the consequence of non-uniform structure is, as a rule, variation of yield stress and stress-strain characteristics. The consequence of this effect is that if material subjected to drawing consists of differing structure, the effective draw ratio in various sections will also be different.

[00054] Turbulent quench medium flow such as eddy currents can cause molten filaments to come in contact with one another and stick. These stuck fibers can also lead to downstream filament breakage problems.

[00055] To minimize problems of the foregoing types, the quenching zone or chamber used may be designed and configured such that all of the filament bundles are exposed to substantially the same quenching conditions during the same time frame. An important factor in creating such uniform quenching conditions within the quenching zone relates to provision of controlled and uniform flow of the cooling gas, e.g., air, during its introduction into, flow through, and exit from the quenching zone or chamber.

[00056] A number of features can be used to improve the uniformity of quench air flow. Baffles can be positioned in the chimney to prevent air flowing around the bundle versus through the bundle. These baffles can be adjusted to also prevent eddy currents or turbulent air in the chimney that would normally result in stuck, molten filaments. Perforations in the chimney doors or tubes can also be used to better control turbulence of the quench medium. U.S. Patent Nos. 3,108,322, 3,936,253 and 4,045,534, incorporated herein by reference, disclose the use of baffles and perforations in chimney quench systems to improve quench and reduce stuck filaments.

[00057] Another modification that can be used to improve positional uniformity is use of a monomer collection device that allows for positional adjustment as well as adjustment in terms of overall vacuum pulled across the machine. Such a device is disclosed in U.S. Patent No. 5,219,585. A suitable monomer collection device can also have a larger rectangular opening that can be used to pull additional air if needed though the bundle but controlled to prevent filaments from leaving the bundle.

[00058] A combination of some or all of the foregoing spinning and quenching features can be employed to ensure spun supply uniformity, i.e., more uniform undrawn fibers in terms of denier per filament, crystailinity, etc. Such fibers can accordingly be drawn more during the drawing/annealing step hereinafter described without an undue incidence of filament breaks. This in turn permits preparation of nylon staple fibers of higher tenacity at 7% elongation and at break.

[00059] The quenched spun filaments which may be formed using at least some of the foregoing uniformity-enhancing techniques can be combined into one or more tows. Such tows formed from filaments from one or more spinnerets are then drawn and annealed, such as by a two stage continuous operation, although single or additional multiple stage operation may also be useful. [00060] Drawing of the tows is generally carried out primarily in an initial or first drawing stage or zone wherein bands of tows are passed between a set of feed rolls and a set of draw rolls (operating at a higher speed) to increase the crystalline orientation of the filaments in the tow. The extent to which tows are drawn can be quantified by specifying a draw ratio which is the ratio of the higher peripheral speed of the draw rolls to the lower peripheral speed of the feed rolls. For a two stage drawing operation, the effective draw ratio is calculated by multiplying the 1^st draw ratio and the 2^nd draw ratio.

[00061] A first drawing stage or zone may include several sets of feed and draw rolls as well as other tow guiding and tensioning rolls such as snubbing pins. Draw roll surfaces may be made of metal, e.g., chrome, or ceramic.

[00062] Ceramic draw roll surfaces have been found to be particularly advantageous in permitting use of the relatively higher draw ratios specified for use in connection with the staple fiber preparation process herein. Ceramic rolls improve roll life as well as provide a surface that is less prone to wrap. An article appearing the International Fiber Journal (International Fiber Journal, 17, 1 , Feb 2002: "Textile and Bearing Technology for Separator Rolls, Zeitz and el.) as well as U.S. Patent No. 4,794,680, both incorporated herein by reference, also disclose the use of ceramic rolls in to improve roll life and reduce fiber adherence to roll surface.

[00063] Particular arrangements of apparatus elements for effecting drawing of the tows are described in the hereinbefore mentioned Hebeler U.S. Patent Nos. 3,044,250, 3,188,790, 3,321 ,448 and 3,459,845, and in Thompson U.S. Patent Nos. 5,093,195 and 5,011 ,645, all of which are incorporated herein by reference. Ceramic rolls can, for example, be installed as some or all of the rolls labeled as Elements 12, 13 and 22 in Figure 2 of the Thompson U.S. Patent No. 5,093,195.

[00064] While the greatest extent of drawing of the tows of filaments herein takes place in an initial or first drawing stage or zone, some additional drawing of the tows may also take place in a second or annealing and drawing stage or zone hereinafter described. The total amount of draw to which the filament tows herein are subjected can be quantified by specifying a total effective draw ratio which takes into account drawing that occurs in both a first initial drawing stage or zone and in a second zone or stage where annealing and some additional drawing may be conducted simultaneously.

[00065] In some processes, the tows of nylon filaments are subjected to a total effective draw ratio of from 2.3 to 5.0, including from 3.0 to 4.0. The draw ratio employed will generally be larger as the denier per filament of the tows becomes larger.

[00066] In an example of one particular process suitable for producing nylon staple to be used in the fabrics disclosed herein, most of the drawing of the tows, as noted hereinbefore, occurs in the first or initial drawing stage or zone. In particular, from 85% to 97.5%, including from 92% to 97%, of the total amount of draw imparted to the tows can take place in a first or initial drawing stage or zone. The drawing operation in the first or initial stage will generally be carried out at whatever temperature the filaments have when passed from the quench zone of the melt spinning operation. Frequently, this first stage drawing temperature will range from 80°C to 125°C.

[00067] From a first or initial drawing stage or zone, the partially drawn tows may be passed to a second annealing and drawing stage or zone wherein the tows may be simultaneously heated and further drawn. Heating of the tows to effect annealing serves to increase crystallinity of the nylon polymer of the filaments. In this second annealing and drawing stage or zone, the filaments of the tows may be subjected to an annealing temperature of from 145°C to 205°C, such as from 165°C to 205°C. The temperature of the tow in this annealing and drawing stage may be achieved by contacting the tow with a steam-heated metal plate that is positioned between the first stage draw and the second stage drawing and annealing operation.

[00068] After the annealing and drawing stage of the process as just described, the drawn and annealed tows are cooled to a temperature of less than 80°C, such as less than 75°C. Throughout the drawing, annealing and cooling operations described herein, the tows may be maintained under controlled tension and accordingly are not permitted to relax.

[00069] After drawing, annealing and cooling, the multifilament tows are converted into staple fiber in conventional manner, for example using a staple cutter. Staple fiber formed from the tows will frequently range in length from 2 to 13 cm (0.79 to 5.12 inches). For example, staple fibers may range from 2 to 12 cm (0.79 to 4.72 inches), from 2 to 12.7 cm (0.79 to 5.0 inches), or from 5 to 10 cm can be formed. The staple fiber herein can optionally be crimped.

[00070] The nylon staple fibers formed in accordance with a process as disclosed herein will generally be provided as a collection of fibers, e.g., as bales of fibers, having a denier per fiber of from 1.0 to 3.0. When staple fibers having a denier per fiber of from 1.6 to 1.8, are to be prepared, a total effective draw ratio of from 3.12 to 3.40, such as from 3.15 to 3.30, can be used in the process herein to provide staple fibers of the requisite load-bearing capacity. When staple fibers having a denier per fiber of from 2.5 to 3.0 or 2.3 to 2.7 are to be prepared, a total effective draw ratio of from 3.5 to 4.0, or from 3.74 to 3.90, may be used in the process herein to provide staple fibers of the requisite load- bearing capacity.

[00071] The nylon staple fibers herein will have a load-bearing capacity of greater than 2.5, such as 2.75 to 3.2 or greater than 3.2 grams per denier, measured as tenacity (T₇) at 7% elongation. The T₇ values of the nylon staple fibers herein will range from 3.3 to 5.0 grams per denier, including from 3.3 to 4.0, from 3.4 to 3.7, and 3.3 to 4.5 grams per denier. The nylon staple fibers of some aspects of the disclosed NYCO fabrics can have a tenacity T at break of at least 6.0 grams per denier, including a tenacity at break of greater than 6.2, 6.4, 6.8 or from 7.0 to 8.0 grams per denier.

[00072] Nylon staple fibers prepared from nylon polymer having an RV value higher than that generally obtained via polymerization in a continuous polymerizer or batch autoclave, and processed in accordance with the spinning, quenching, drawing and annealing procedures described herein, can exhibit suitably high load-bearing capacity as quantified by their T₇ tenacity at 7% elongation values, even at lower draw ratios. When such relatively high RV nylon staple fibers of suitably high load-bearing capacity are blended with cotton staple fibers, textile yarns of suitably high strength can be realized. NYCO fabrics woven from such yarns exhibit the advantages hereinbefore described with respect to abrasion resistance, strength, durability, optionally lighter weight, comfort and/or lower cost.

Test Methods

[00073] When the various parameters, properties and characteristics for the polymers, fibers, yarns and fabrics herein are specified, it is understood that such parameters, properties and characteristics can be determined using the following types of testing procedures and equipment:

Nylon Polymer Relative Viscosity

[00074] The formic acid RV of nylon materials used herein refers to the ratio of solution and solvent viscosities measured in a capillary viscometer at 25°C. The solvent is formic acid containing 10% by weight of water. The solution is 8.4% by weight nylon polymer dissolved in the solvent. This test is based on ASTM Standard Test Method D 789. Preferably, the formic acid RVs are determined on spun filaments, prior to or after drawing, and can be referred to as spun fiber formic acid RVs.

Instron Measurements on Staple Fibers

[00075] All Instron measurements of staple fibers herein are made on single staple fibers, taking appropriate care with the clamping of the short fiber, and making an average of measurements on at least 10 fibers. Generally, at least 3 sets of measurements (each for 10 fibers) are averaged together to provide values for the parameters determined. Filament Denier

[00076] Denier is the linear density of a filament expressed as weight in grams of 9000 meters of filament. Denier can be measured on a Vibroscope from Textechno of Munich, Germany. Denier times (10/9) is equal to decitex (dtex). Denier per filament can be determined gravimetrically in accordance with ASTM Standard Test Method D 1577.

Tenacity at Break

[00077] Tenacity at break (T) is the maximum or breaking force of a filament expressed as force per unit cross-sectional area. The tenacity can be measured on an Instron model 1 130 available from Instron of Canton, Mass. and is reported as grams per denier (grams per dtex). Filament tenacity at break (and elongation at break) can be measured according to ASTM D 885.

Filament Tenacity at 7% Elongation

[00078] Filament tenacity at 7% elongation (T₇) is the force applied to a filament to achieve 7% elongation divided by filament denier. T₇ can be determined according to ASTM D 3822.

Yarn Strength

[00079] Strength of the spun nylon/cotton yarns herein can be quantified via a Lea Product value or yarn breaking tenacity. Lea Product and skein breaking tenacity are conventional measures of the average strength of a textile yarn and can be determined in accordance with ASTM D 1578. Lea Product values are reported in units of pounds force. Breaking tenacity is reported in units of cN/tex.

Fabric Weight

[00080] Fabric weight or basis weight of the woven fabrics herein can be determined by weighing fabric samples of known area and calculating weight or basis weight in terms of grams/m² or oz/yd² in accordance with the procedures of the standard test method of ASTM D 3776. Another useful test relating to fabric weight is EN ISO 12127 : 1998.

Fabric Grab Strength

[00081] Fabric grab strength can be measured in accordance with ASTM D 5034. Grab strength measurements are reported in pounds- force in both warp and fill directions.

Fabric Tear Strength

[00082] Fabric tear strength can be measured in accordance with ISO 13937-2:2000 titled Determination of tear force using an Instron tester.

Fabric Abrasion Resistance

[00083] Fabric abrasion resistance can be determined in accordance with ISO 12947-1 :1998 titled Determination of the abrasion resistance of fabrics by the Martindale method using woolen abradant with a 12kPa weight.

Fabric Tensile Strength

[00084] Fabric tensile strength can be determined in accordance with ISO 13934-1 :1999 titled Determination of maximum force and elongation at maximum force using the strip method.

Air Permeability

[00085] Fabric air permeability can be determined in accordance with ISO 9237: 995 tilted Determination of the permeability of fabrics to air.

Thread Count

[00086] Fabric thread count can be determined in accordance with BS EN 1049-2:1994 titled Determination of number of threads per unit length. Fiber Content

[00087] The fiber content can be determined in accordance with Directive 96/73/EC Method 7 titled Methods for the Quantitative Chemical Analysis of Textile Fiber Mixtures.

Cover Factor

[00088] Cover Factor is a number that indicates the extent to which a specified area of the surface of the fabric is covered by one or more set of threads or yarns. Cover factor can be calculated with the following formula: threads/cm x vfex x 10^~1.

[00089] The features and advantages of the present invention are more fully shown by the following examples which are provided for purposes of illustration, and are not to be construed as limiting the invention in any way.

EXAMPLES

[00090] In the examples herein, Fabrics 1 - 9 discussed above were tested for various mechanical properties. Fabrics 6-9, represent a heavy weight version of Fabrics 1 - 5.

[00091] Additionally, nylon staple fibers were produced in accordance with Thompson (U.S. Patent Nos. 5,093,195 and 5,011 ,645) and tested for various mechanical properties. Accordingly, polymerization of a salt resulting from the reaction of hexamethylenediamine and adipic acid was carried out in a continuous polymerizer to yield homopolymer nylon 6,6 (polyhexamethylene adipamide) containing a polyamidation catalyst (i.e., manganous hypophosphite obtained from Occidental Chemical Company with offices in Niagara Falls, N.Y.) in concentration by weight of 16 parts per million. The polymer was then fed to a spin pack for melt spinning through a spinneret into filaments. Filaments extruded through the spinneret were passed through a cross-flow quench zone and then converged into a continuous filament tow. The RV of the extruded filaments was about 55.

[00092] The continuous filament tow was then drawn and annealed by procedures and with apparatus described in U.S. Patent No. 5,093,195. The drawn and annealed tow was then cooled to below 80°C and cut into nylon staple fibers having the characteristics shown in Table 3.

[00093] Fabrics 1-5 were manufactured on a Dobby loom capable of lifting 16 shafts. The warp yarn is sized using a PVA type size, and the percent size was between 12% and 14%. The warp length was 400 meters. A minimum of 2 weft feeders was employed. The ends per centimeter in the loom were 35.8 and the picks per centimeter in the loom were 23.5. The reed specification was 2 ends per dent. The finished size of Fabrics 1-5 is 40 cm x 25 cm.

[00094] Table 1 below provides the fabric construction details for light weight fabrics 1-5, which were made in accordance with this invention and are discussed above, as well as for a comparative light weight 85/15 cotton-polyester Disruptive Pattern Material (DPM) 2/1 twill fabric with ripstop in the weft only, designated Fabric A.

[00095] Table 2 below discloses the Tensile Strength (Newtons), Tear Strength (Newtons), Air Permeability (l/m²/s), and Martindale Abrasion (Rubs) of Fabrics 1 - 5, and the light weight comparative Fabric A which are described above. The data shows that light weight fabrics of some embodiments of the present invention were able to achieve greater than 250,000 Martindale Abrasion rubs.

[00096] The properties of the nylon staple used in manufacturing the fabrics that are characterized in Tables 1 and 2 are shown in Table 3.

[00097] Table 4 below provides the fabric construction details for heavy weight fabrics 6-9, which are made in accordance with this invention and are discussed above, as well as a comparative heavy weight 65/35 cotton-polyester twill fabric designated Fabric B. TABLE 4

Fabrics 6-9 Fabric B

Fabric weight Fabric 6 - 230 + 5 g/m² 231

Fabric 7 - 300 + 5 g/m²

Fabric 8 - 230 + 5 g/m²

Fabric 9 - 300 + 5 g/m²

Yarn Blend Ratio (weight%): 52 nylon 6,6 / 48 cotton 65 cotton / 35 polyester

(staple)

Yarn Counts 25/1 CC

Filament Yarn 240 dtex nylon 6,6 None

(textured)

Finished Thread Count/cm Ends: Ends: 43

Fabric 6 - Ends:26/cm,

Fabric 7 - Ends:32/cm,

Fabric 8 - Ends:26/cm,

Fabric 9- Ends:32/cm,

Picks: Picks: 37

Fabric 6 - Picks:16/cm

Fabric 7 - Picks:22/cm

Fabric 8 - Picks: 16/cm

Fabric 9- Picks:22/cm

[00098] Table 5 below discloses the Tensile Strength (Newtons), Tear Strength (Newtons), Air Permeability (l/m²/s), and Martindale Abrasion (Rubs) of Fabrics 6-9 and the heavy weight comparative Fabric B. The data demonstrates that heavy weight fabric of each of the examples that are shown were able to achieve greater than 250,000 Martindale rubs.

[00099] Table 6 discloses the properties of several higher tenacity nylon staple fibers that are also suitable for use in the inventive fabrics of this disclosure.

[00100] Nylon staple fiber of relatively lower and higher T₇ values, respectively, were each ring spun into nylon/cotton blend yarns (20/1 cotton count) with various nylon to cotton staple fiber ratios. Table 7 illustrates the increases in yarn strength that were achieved by utilizing fiber with a higher T₇ value. Use of such yarns with relatively higher load bearing capacity will, in turn, enable the manufacture of fabrics with relatively higher durability.

TABLE 7

Comparison of Nylon Fiber Strength and % Nylon Content to Spun Yarn Stren th 20/1 cc

[00101] Nylon staple fiber of 1.7 dpf and a T of 2.9 was ring spun into 50:50 nylon/cotton blend yarns of two different yarn counts. For comparison, nylon staple fiber of .6 dpf and a higher T₇ of 3.4 was ring spun into comparable nominal 50:50 nylon/cotton blend yarns. The same cotton type and yarn processing equipment was used in preparing all yarns. Such yarns are compared in yarn strength and evenness as shown in Table 8. Evenness is a measure of the variation in denier or diameter along the length of the yarn and is obtained by use of an Uster tester. The measurements reported were obtained with such an Uster tester based on an optical sensor,

[00102] While there have been described what are presently believed to be the preferred aspects of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to include all such changes and modifications as fall within the true scope of the invention.

Claims

1. A nylon/cotton (NYCO) fabric woven from textile yarns in both a warp and weft (fill) direction wherein said textile yarns woven in at least one direction comprise blended cotton staple fibers and nylon staple fibers in a weight ratio of cotton staple fibers to nylon staple fibers ranging from 20:80 to 80:20; and wherein said nylon staple fibers have a denier per filament of from about 1.0 to about 3.0, a tenacity of greater than 6.0 grams per denier, and a load-bearing capacity of greater than 2.5 grams per denier, measured as tenacity (T₇) at 7% elongation, wherein said fabric further comprises at least one type of filament or yarn comprising said filament in either the warp direction, weft direction, or both.

2. NYCO fabric according to Claim 1 , wherein said at least one filament may be either nylon or polyester.

3. The NYCO fabric according to Claim 1 , wherein said at least one filament is optionally textured nylon filament.

4. A NYCO fabric according to any of Claims 1 , 2, or 3, wherein said nylon staple fibers have a tenacity of about 6.8 grams per denier, and a load-bearing capacity of from about 2.75 to about 3.2 grams per denier, measured as tenacity (T₇) at 7% elongation.

5. A NYCO fabric according to Claim 4, wherein said weight ratio of cotton staple fibers to nylon staple fibers is 48:52 and said nylon filament is nylon 6,6.

6. A NYCO fabric according to Claim 5, having a fabric weight of about 200 grams/m² or less.

7. A NYCO fabric according to Claim 5, having a fabric weight of between about 75 grams/m² to about 200 grams/m².

8. A NYCO fabric according to Claim 5, having a tensile strength in the warp direction of from about 850 Newtons to about 960 Newtons, wherein said tensile strength is determined according to ISO 13934- 1 :1999.

9. A NYCO fabric according to Claim 5, having a tensile strength in the weft direction of from about 400 Newtons to about 610 Newtons, wherein said tensile strength is determined according to ISO 13934- 1 :1999.

10. A NYCO fabric according to Claim 5, having a tear strength in the warp direction of from about 50 Newtons to about 85 Newtons, wherein said tear strength is determined according to ISO 13937- 2:2000.

11. A NYCO fabric according to Claim 5, having a tear strength in the weft direction of from about 40 Newtons to about 85 Newtons, wherein said tear strength is determined according to ISO 13937- 2:2000.

12. A NYCO fabric according to Claim 5, having an air permeability of at least 50 l/m²/s, wherein said air permeability is determined according to ISO 9237:1995.

13. A NYCO fabric according to Claim 5, having a Martindale Abrasion of at least 130,000 rubs, wherein Martindale Abrasion is determined according to ISO 12947-1 :1998.

14. A NYCO fabric according to Claim 5, having a tensile strength in the warp direction of at least 850 Newtons to about 2100 Newtons, wherein said tensile strength is determined according to ISO 13934- 1 :1999.

15. A NYCO fabric according to Claim 5, having a tensile strength in the weft direction of at least 420 Newtons to about 1600 Newtons, wherein said tensile strength is determined according to ISO 13934- 1 :1999.

16. A NYCO fabric according to Claim 5, having a tear strength in the warp direction of at least 50 Newtons to about 170 Newtons, wherein said tear strength is determined according to ISO 13937- 2:2000.

17. A NYCO fabric according to Claim 5, having a tear strength in the weft direction of at least 40 Newtons to about 150 Newtons, wherein said tear strength is determined according to ISO 13937- 2:2000.

18. A NYCO fabric according to Claim 1 wherein the yarns woven in the weft direction comprise nylon staple fibers having a denier per filament of from 1.6 to 1.8 and the yarns woven in the warp direction comprise nylon staple fibers having a denier per filament of from 2.3 to 2.7.

19. A NYCO fabric woven from textile yarns in both a warp and weft (fill) direction wherein said textile yarns woven in both directions comprise blended cotton staple fibers and nylon staple fibers in a weight ratio of cotton staple fibers to nylon staple fibers ranging from 20:80 to 80:20; and further characterized in that the yarns woven in the weft (fill) direction comprise nylon staple fibers having a denier per filament of from 1.3 to 2.0 and the yarns woven in the warp direction comprise nylon staple fibers having a denier per filament of from 2.5 to 3.0.

20. A NYCO fabric woven from textile yarns in both a warp and weft (fill) direction wherein said textile yarns woven in at least one direction comprise blended cotton staple fibers and nylon staple fibers in a weight ratio of cotton staple fibers to nylon staple fibers ranging from about 20:80 to 80:20; and further characterized in that said nylon staple fibers are made from nylon having a formic acid relative viscosity (RV) of from 45 to 100, said nylon fibers further having a denier per filament of from 1.0 to 3.0, a tenacity of at least 6.0 grams per denier and a load-bearing capacity of greater than 2.5, grams per denier, measured as tenacity (T₇) at 7% elongation, wherein said fabric further comprises at least one optionally textured nylon filament in either the warp direction, weft direction, or both.