AND WOVEN FABRICS CONTAINING SAME

FIELD OF THE INVENTION

The present invention relates generally to conformable microporous fibers, and more specifically, to conformable microporous fibers having a node and fibril structure that are highly breathable. Woven fabrics containing the conformable microporous fibers are also provided.

BACKGROUND OF THE INVENTION

Waterproof, breathable garments are well-known in the art. These garments are often constructed from multiple layers in which each layer adds a certain functionality. For example, a garment could be constructed using an outer textile layer, a waterproof, breathable film layer, and an inner textile layer. The outer and inner textile layers provide protection to the breathable film layer. However, the addition of outer and inner fabric layers not only adds weight to an article of apparel, it also results in materials having the potential for a high water pick-up on the outer surface. The pick-up of water by the outer fabric layer permits for thermal conductivity and the passage of the temperature of the water through the fabric and to the wearer. This may be detrimental in cases where the wearer is in a cold environment and the cold is transported to the body of the wearer. In addition, water pick-up may lead to condensation on the inside of the garment, making the wearer feel wet. Further, the color of the outer fabric may become discolored or darken upon water pick-up, thus reducing the aesthetic appearance of the garment. Also, depending on the outer fabric, there may be a long dry time associated with the fabric itself, forcing the wearer to endure the disadvantages associated with the water pick-up for a longer time. Additionally, the fibers associated with conventional fabrics used in the inner and outer layer are constructed of multifilament fibers, which permit water and/or contaminants between the filaments, Additionally, because multifilament fibers are loosely packed for breathability in the fabric, water can undesirably fill the space between the fibers.

Thus, there exists a need in the art for a fiber to make woven fabrics for use in garments that is highly breathable, has a high water entry pressure, and has a low water pick-up.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a woven fabric that includes warp and weft expanded polytetrafluoroethylene (ePTFE) fibers that have a microporous structure of nodes and fibrils, where the width of the ePTFE fiber is greater than the width allotted to the ePTFE fiber based on the end count or pick count of the woven fabric. This difference in width causes the ePTFE fiber to fold upon itself to conform to the weave spacing provided between the crossovers of the warp and weft fibers. The ePTFE fibers may be monofilament fibers. The ePTFE fibers may have a density less than about 1 .2 g/cm ³ , an aspect ratio greater than about 15, and a substantially rectangular cross sectional configuration. Advantageously, the ePTFE woven fabric possesses both a high moisture vapor transmission and a high water entry pressure. In particular, the woven fabric has a moisture vapor transmission rate greater than about 1 0,000 g/m ² /24 hours and a water entry pressure greater than about 1 kPa. Thus, the woven fabric is highly breathable, has a low water pick-up, and is highly water resistant.

It is another object of the present invention to provide a woven fabric that includes a plurality of warp and weft fibers where each of the warp and weft fibers include expanded polytetrafluoroethylene fibers that have a density less than about 1 .2 g/cm ³ and a substantially rectangular cross sectional

configuration. The ePTFE fibers may be monofilament fibers. At least one of the warp and weft ePTFE fibers may have an aspect ratio greater than about 15. In at least one exemplary embodiment, the width of the ePTFE fibers is greater than the number of picks per inch of the woven fabric. Further, the woven fabric has an average stiffness less than about 300 g and a water pick-up less than 30 gsm. The warp fibers and weft fibers may have a fluoroacrylate coating to render the woven fabric oleophobic. A fiuoropolymer membrane, or other functional membranes or protective layer, may be affixed to the woven fabric on a side opposing the fluoroacrylate coating. In some embodiments, a textile may be affixed to the fluoropolymer membrane to form a laminated article. In other embodiments, a fluoropolymer membrane and/or a textile may be affixed to the woven fabric without the application of a coating.

It is a further object of the invention to provide a woven fabric that includes warp and weft fibers of expanded polytetrafluoroethylene fibers having an aspect ratio greater than about 15 and a substantially rectangular cross- section configuration. The woven fabric has a water entry pressure greater than about 1 kPa and a moisture vapor transmission rate greater than about 10,000 g/m ² /24 hours. The ePTFE fibers may be monofilament fibers. Additionally, the fibers may have a pre-weaving thickness less than about 100 microns, a pre- weaving width less than about 4.0 mm, and a pre-weaving density less than about 1 .0 g/cm ³ . Further, the ePTFE fibers have a node and fibril structure where the nodes are interconnected by fibrils that define passageways through the fiber. The fibrils may have a length from about 5 microns to about 120 microns.

It is yet another object of the invention to provide a woven fabric that includes warp and weft fluoropolymer fibers where at least one of the warp and weft fluoropolymer fibers is in a folded configuration along a length of the fiber. In at least one exemplary embodiment, the fluoropolymer fibers are ePTFE fibers that have a density less than about 1.2 g/cm ³ and have a substantially rectangular configuration. In exemplary embodiments, the ePTFE fibers have a pre-weaving density less than about 0.85 g/cm ³ . The woven fabric has a moisture vapor transmission rate greater than about 10,000 g/m ² /24 hours and a water entry pressure greater than about 1 kPa. In addition, the woven fabric has a tear strength of at least 30 N and an average stiffness of less than about 300 g. In at least one exemplary embodiment, the width of the fluoropolymer fiber is greater than the width allotted to the fluoropolymer fiber in the woven fabric based on the end count or pick count of the woven fabric.

It is also an object of the present invention to provide a woven fabric that includes conformable warp and weft fluoropolymer fibers where at least one of the warp and weft fibers have a node and fibril structure that form passageways through the fiber. The fibrils may have a length from about 5 microns to about 120 microns. In at least one embodiment, the fluoropolymer fibers are ePTFE fibers that have a pre-weaving density less than about 1.0 g/cm ³ , and in other embodiments, less than about 0.85 g/cm ³ . The conformability of the fiber permits the fiber to curl and/or fold upon itself to conform to weave spacing provided between the crossovers of the warp and weft fibers in a woven configuration. Additionally, a functional membrane or protective layer, such as a fluoropolymer membrane, may be affixed to the ePTFE woven fabric. In some embodiments, a textile is affixed to the fluoropolymer membrane to form a laminated article.

It is yet another object of the present invention to provide a

monofilament fiber that includes expanded polytetrafluoroethylene. The ePTFE monofilament fiber has a density less than or equal to 1.0 g/cm ³ , a thickness less than about 100 microns, a width less than about 4.0 mm, an aspect ratio greater than about 15, and a substantially rectangular cross-section configuration. In addition, the fiber has a tenacity greater than about 1 .6 cN/dtex and a break strength of at least about 1.5 N. The ePTFE monofilament fiber may have thereon a fluoroacrylate coating, or other oleophobic treatment, Additionally, the ePTFE monofilament fibers have a node and fibril configuration where the nodes and fibrils define passageways through the fiber, The fibril length may be from about 5 microns to about 120 microns. Further, the ePTFE monofi lament fiber is conformable such that in a woven configuration, the ePTFE

monofilament fiber folds upon itself to conform to weave spacing provided between the crossovers of the warp and weft fibers in the woven fabric. Such ePTFE monofilament fibers are utilized in exemplary embodiments of the invention to form woven fabrics that may ultimately be used in an article that demands high moisture vapor transmission and high water entry pressure {i.e., high breathability and high resistance to water).

It is an advantage of the present invention that even when the ePTFE fiber is tightly woven, the ePTFE woven fabric is highly breathable and has a high water entry pressure. It is another advantage of the present invention that the ePTFE fibers may be tightly woven into a woven fabric that is highly breathable yet possesses a low air permeability.

It is also an advantage of the present invention that the woven fabric is quiet, soft, and drapable.

It is yet another advantage of the present invention that the high aspect ratio of the ePTFE fibers enables low weight per area fabric, easier and more efficient reshaping, and can achieve high water resistance in a woven fabric with less picks and ends per inch.

It is a feature of the present invention that the ePTFE fibers curl and/or fold upon themselves to conform to the weave spacing provided between the crossovers of the warp and weft fibers in the woven fabric.

It is also a feature of the present invention that woven fabrics constructed from the ePTFE fibers have a flat or substantially flat weave and a

corresponding smooth surface.

It is another feature of the present invention that the ePTFE fibers have a substantially rectangular cross-section configuration, particularly prior to weaving. BRIEF DESCRIPTIONS OF FIGURES

The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a scanning electron micrograph (SEM) of the top surface of an exemplary ePTFE fiber taken at 1 OOOx magnification according to one exemplary embodiment of the invention;

FIG. 2 is a scanning electron micrograph of a side of the ePTFE fiber depicted in FIG. 1 taken at l OOOx magnification;

FIG. 3 is scanning electron micrograph of the top surface of a 2/2 woven twill fabric of the fiber depicted in FIG. 1 taken at 150x magnification;

FIG. 4 is a scanning electron micrograph of a side of the woven fabric depicted in FIG. 3 taken at 150x magnification; FIG. 5 is a scanning electron micrograph of the top surface of the 2/2 woven twill fabric depicted in FIG. 3 having thereon a fluoroacrylate coating taken at 150x magnification;

FIG. 6 is a scanning electron micrograph of a side of the woven fabric depicted in FIG. 5 taken at 150x magnification;

FIG. 7 is a scanning electron micrograph of the top surface of the 2/2 woven twill fabric illustrated in FIG. 5 having laminated thereto an ePTFE membrane taken at 150x magnification;

FIG. 8 is a scanning electron micrograph of a side of the article depicted in FIG. 7 taken at l OOx magnification;

FIG. 9 is a scanning electron micrograph of a side of the fabric depicted in FIG. 7 taken at l OOOx magnification;

FIG. 10 is a scanning electron micrograph of the top surface of the woven fabric illustrated in FIG. 5 laminated to a textile taken at 150x magnification according to another exemplary embodiment of the invention;

FIG. 1 1 is a scanning electron micrograph of a side of the article depicted in FIG. 10 taken at l OOx magnification;

FIG. 12 is a scanning electron micrograph of a side of the article depicted in FIG, 10 taken at 500x magnification;

FIG. 13 a scanning electron micrograph of the top surface of a woven fabric having laminated thereto an ePTFE membrane and a textile according to an exemplary embodiment of the invention taken at 150x magnification;

FIG. 14 is a scanning electron micrograph of a side of the article depicted in FIG. 13 taken at l OOx magnification;

FIG. 15 is a scanning electron micrograph of a side of the article depicted in FIG. 13 taken at 300x magnification;

FIG. 16 is a scanning electron micrograph of the top surface of a plain woven fabric according to one exemplary embodiment of the invention taken at 150x magnification;

FIG, 17 is a scanning electron micrograph of a side of the fabric depicted in FIG. 16 taken at 250x magnification; FIG. 18 is scanning electron micrograph of the top surface of the plain woven fabric illustrated in FIG. 16 having thereon a fluoroacrylate coating taken at 150x magnification;

FIG. 1 is a scanning electron micrograph of a side of the woven fabric depicted in FIG. 18 taken at 250x magnification;

FIG. 20 is a scanning electron micrograph of the top surface of the woven fabric depicted in FIG. 16 having laminated thereto an ePTFE membrane and a textile taken at 150x magnification according to an exemplary

embodiment of the invention;

FIG. 21 is a scanning electron micrograph of a side view of the article depicted in FIG. 20 taken at 250x magnification;

FIG. 22 is a scanning electron micrograph of the top surface of an exemplary ePTFE fiber taken at l OOOx magnification according to another exemplary embodiment of the invention;

FIG. 23 is a scanning electron micrograph of a side of the ePTFE fiber depicted in FIG. 22 taken at l OOOx magnification;

FIG. 24 is a scanning electron micrograph of the top surface of a 2/2 twill fabric of the ePTFE fiber depicted in FIG. 22 taken at 150x magnification;

FIG. 25 is a scanning electron micrograph of a side of the fabric depicted in FIG. 24 taken at 200x magnification;

FIG. 26 is a scanning electron micrograph of the top surface of the woven twill fabric depicted in FIG. 16 having thereon a fluoroacrylate coating taken at 150x magnification;

FIG. 27 is a scanning electron micrograph of a side of the fabric depicted in FIG. 26 taken at 200x magnification;

FIG. 28 is a scanning electron micrograph of the top surface of an exemplary ePTFE fiber according to a further embodiment of the invention taken at l OOOx magnification;

FIG. 29 is a scanning electron micrograph of a side of the fiber depicted in FIG. 28 taken at l OOOx magnification;

FIG. 30 is a scanning electron micrograph of the top surface of a 2/2 twill woven fabric of the ePTFE fiber illustrated in FIG. 26 taken at 150x magnification; FIG. 31 is a scanning electron micrograph of a side of the fabric depicted in FIG, 30 taken at 150x magnification;

FIG. 32 is a scanning electron micrograph of the top surface of a high density comparative ePTFE fiber taken at l OOOx magnification;

FIG. 33 is a scanning electron micrograph of a side of a woven fabric of the fiber depicted in FIG. 32 taken at l OOOx magnification;

FIG. 34 is a scanning electron micrograph of the top surface of a 2/2 twill woven comparative fabric utilizing a comparative high density ePTFE fiber taken at 150x magnification;

FIG. 35 is a scanning electron micrograph of a side of the fabric depicted in FIG. 34 taken at 150x magnification;

FIG. 36 is a scanning electron micrograph of a top surface of an exemplary fiber taken at l OOOx magnification;

FIG. 37 is a scanning electron micrograph of a side of the fiber depicted in FIG. 36 taken at 1 OOOx magnification;

FIG. 38 is a scanning electron micrograph of the top surface of a woven fabric of the fiber shown in FIG. 36 taken at 150x magnification;

FIG, 39 is a scanning electron micrograph of a side of the fabric depicted in FIG. 38 taken at 150x magnification;

FIG, 40 is a schematic illustration depicting a side view of exemplary fibers folding into a folded configuration to fit into the space allotted to the fiber in the woven configuration;

FIG. 41 is a schematic illustration depicting a top view of exemplary fibers folding into a folded configuration to fit into the space allotted to the fiber in the woven configuration;

FIG. 42 is a scanning electron micrograph of the top surface of an exemplary plain weave fabric with a 40 X 40 thread count taken at 150x magnification;

FIG. 43 is a scanning electron micrograph of a side of the woven fabric depicted in FIG. 42 taken at 150x magnification;

FIG. 44 is a scanning electron micrograph of a side of the woven fabric depicted in FIG. 42 taken at 300x magnification; FIG 45 is a scanning electron micrograph of a side of the woven fabric depicted in FIG. 42 taken at 400x magnification;

FIG. 46 is a scanning electron micrograph of the top surface of a comparative non-porous ePTFE fiber taken at l OOOx magnification;

FIG. 47 is a scanning electron micrograph of a side of the fiber depicted in FIG. 46 taken at l OOOx magnification;

FIG. 48 is a scanning electron micrograph of a woven fabric of the fiber depicted in FIG. 46 taken at 150x magnification;

FIG. 49 is a scanning electron micrograph of a side of the woven fabric of FIG. 48 taken at 150x magnification;

FIG. 50 is a scanning electron micrograph of the top surface of a comparative woven fabric of a comparative high density ePTFE fiber taken at 150x magnification;

FIG. 51 is a scanning electron micrograph of a side surface of the woven fabric illustrated in FIG. 50 taken at 150x magnification; and

FIG. 52 is a scanning electron micrograph illustrating gap width measurements.

DEFINITIONS

The terms "monofilament fiber" and "monofilament ePTFE fiber" as used herein are meant to describe an ePTFE fiber that is continuous or substantially continuous in nature which may be woven into a fabric.

The terms "fiber" and "ePTFE fiber" as used herein are meant to include monofilament ePTFE fibers as well as a plurality of monofilament ePTFE fibers, such as, for example, fibers in a side-by-side configuration, in a bundled configuration, or in a twisted or otherwise intermingled form.

The term "conformable" and "conformable fiber" as used herein are meant to describe fibers that are capable of curling and/or folding upon themselves to conform to weave spacing provided between the crossovers of the warp and weft fibers and as determined by the number of picks per inch and/or ends per inch of the warp and weft fibers.

"High water entry pressure" as used herein is meant to describe a woven fabric with a water entry pressure greater than about 1 kPa. The phrase "low water pick-up" as used herein is meant to denote a woven fabric having a water pick-up less than about 50 gsm.

The term "substantially rectangular configuration" as used herein is meant to denote that the conformable, microporous fibers have a rectangular or nearly rectangular cross section, with or without a rounded or pointed edge (or side).

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to conformable microporous fibers having a node and fibril structure and woven fabrics produced therefrom. A polymer membrane and/or a textile may be laminated to the woven fabric to produce a laminated article. The woven fabric concurrently possesses high moisture vapor transmission (i.e., highly breathable), high water entry pressure, and low water pick-up. The woven fabric can be colorized, such as, for example, by printing. In addition, the woven fabric is quiet, soft, and drapable, making it especially suitable for use in garments, gloves, and in footwear applications, It is to be noted that the terms "woven fabric" and "fabric" may be used interchangeably herein. In addition, the terms "ePTFE fiber" and "fiber", may be

interchangeably used within this application.

The conformable fibers have a node and fibril structure where the nodes are interconnected by fibrils, the space between which defines passageways through the fibers. Also, the conformable fibers are microporous. Microporous is defined herein as having pores that are not visible to the naked eye. The node and fibril structure within the fiber permits the fiber, and fabrics woven from the fiber, to be highly breathable and allow for the penetration of colorants and oleophobic compositions. Also, the matrix provided by the nodes and fibrils allows for the inclusion of desired fillers and/or additives.

It is to be appreciated that with respect to the conformable, microporous fibers; reference is made herein with respect to expanded polytetrafluorethylene (ePTFE) fibers for ease of discussion, However, it is to be understood that any suitable conformable fluoropolymer having a node and fibril structure may be used interchangeably with ePTFE as described within this application. Non- limiting examples of fluoropolymers include, but are not limited to, expanded PTFE, expanded modified PTFE, expanded copolymers of PTFE, fluorinated ethylene propylene (FEP), and perfluoroalkoxy copolymer resin (PFA). Patents have been granted on expandable blends of PTFE, expandable modified PTFE, and expanded copolymers of PTFE, such as, but not limited to, U.S. Patent No. 5,708,044 to Branca; U.S. Patent No. 6,541 ,589 to Baillie; U.S. Patent No.

7,531 ,61 1 to Sabol et al:, U.S. Patent Application No. 1 1/906,877 to Ford; and U.S. Patent Application No. 12/410,050 to Xu et al. The fibril length of the ePTFE fibers ranges from about 5 microns to about 120 microns, from about 10 microns to about 100 microns, from about 15 microns to about 80 microns, or from about 15 microns to about 60 microns,

Additionally, the ePTFE fibers have a substantially rectangular configuration. At least FIGS. 4, 6, 12, 14, 17, 19, 21 , 27, 30, 39, 43, 44, 45 of this application depict exemplary ePTFE fibers having substantially rectangular configurations. As used herein, the term "substantially rectangular

configuration" is meant to denote that the fibers have a rectangular or nearly rectangular cross section. That is, the ePTFE fibers have a width that is greater than its height (thickness). It is to be noted that the fibers may have a rounded or pointed edge (or side). Unlike conventional fibers that must be twisted prior to weaving, the ePTFE fibers can be woven while in a flat state without having to first twist the ePTFE fiber. The ePTFE fibers may be advantageously woven with the width of the fiber oriented so that it forms the top surface of the woven fabric. Thus, woven fabrics constructed from the inventive ePTFE fibers have a flat or substantially flat weave and a corresponding smooth surface. The smooth, planar surface of the fabric enhances the softness of the woven fabric.

In addition, the ePTFE fibers used herein have a low density. More specifically, the fibers have a pre-weaving density less than about 1 .0 g/cm ³ . In exemplary embodiments, the fibers have a pre-weaving density less than about 0.9 g/cm ³ , less than about 0.85 g/cm ³ , less than about 0.8 g/cm ³ , less than about 0.75 g/cm ³ , less than about 0.7 g/cm ³ , less than about 0.65 g/cm ³ , less than about 0.6 g/cm ³ , less than about 0,5 g/cm ³ , less than about 0.4 g/cm ³ , less than about 0.3 g/cm ³ , or less than about 0.2 g/cm ³ , Processes used to make a fabric, such as weaving, fold the ePTFE fibers and may increase the density of the fibers while preserving breathability through the woven fabric. As a result, the fibers may have a post-weaving density less than or equal to about 1 .2 g/cm ³ . The low density of the fiber (both pre- and post-weave) also enhances the breathability of the fiber.

Additionally, the fibers may have a weight per length of about 50 dtex to about 3500 dtex, from about 70 dtex to about 1000 dtex, from about 80 dtex to about 500 dtex, from about 90 dtex to about 400 dtex, from about 100 dtex to about 300 dtex, or from about 100 dtex to about 200 dtex. It is to be appreciated that a lower dtex provides a lower weight/area fabric, which enhances the comfort of a garment formed from the fabric. In addition, the low denier of the ePTFE fiber enables the woven fabric to have a high pick resistance. Pick resistance is referred to as the ability of a fabric to resist the grasping and moving of individual fibers within the fabric. In general, the finer the fiber (e.g., lower denier or dtex) and tighter the weave, a better pick resistance is achieved.

The ePTFE fibers also have a height (thickness) (pre- or post- weaving) less than about 200 microns. In some embodiments, the thickness ranges from about 20 microns to about 150 microns, from 20 microns to about 100 microns, from about 20 microns to about 70 microns, from about 20 microns to 50 microns, from about 20 microns to 40 microns, or from about 26 microns to 36 microns. The ePTFE fibers may have a pre- or post- weaving height (thickness) less than 100 microns, less than 75 microns, less than 50 microns, less then 40 microns, less then 30 microns, or less than 20 microns. The fibers also have a width (pre- or post- weaving) less than about 4.0 mm. In at least one exemplary embodiment, the fibers have a pre- or post- weaving width from about 0.5 mm to about 4.0 mm, from about 0.40 mm to about 3.0 mm, from about 0.45 mm to about 2.0 mm, or from about 0.45 mm to about 1 .5 mm. The resulting aspect ratio (i.e. , width to height ratio) of the ePTFE fibers is greater than about 10. In some embodiments, the aspect ratio is greater than about 15, greater than about 20, greater than about 25, greater than about 30, greater than about 40, or greater than about 50. A high aspect ratio, such as is achieved by the ePTFE fibers, enables low weight per area fabrics, easier and more efficient reshaping, and can achieve high water resistance in a woven fabric with less picks and ends per inch. Further, the ePTFE fibers have a tenacity greater than about 1 ,4 cN/dtex. In at least one embodiment of the invention, the ePTFE fibers have a tenacity from about 1.6 cN/dtex to about 5 cN/dtex, from about 1 .8 cN/dtex to about 4 cN/dtex, or from about 1 .9 cN/dtex to about 3 cN/dtex. Additionally, the ePTFE fibers have a fiber break strength of at least about 1.5 N. In one or more embodiments, the ePTFE fibers have a fiber break strength from about 2 N to about 20 N, from about 2 N to about 15 N, from about 2 N to about 10 N, or from about 2 N to about 5 N.

The ePTFE fibers described herein may be used to form a woven fabric having warp and weft fibers interwoven with one another in a repeating weave pattern. Any weave pattern, such as, but not limited to, plain weaves, satin weaves, twill weaves, and basket weaves, may be used to form the ePTFE fibers into a woven fabric. The ePTFE fiber may be woven flat without folds or creases when the width of the ePTFE fiber is less than the allotted space provided for the fiber based on the number of the picks per inch and/or ends per inch. Such a fiber, when loosely woven, includes visible gaps between the crossovers (intersections) of the warp and weft fibers. As such, the fabric is highly breathable but is not water resistant. Such large gaps in the fabric may be acceptable in applications where, for example, the water resistance is to be provided by another layer or in situations where general areal coverage is desired and water resistance is not critical.

In other embodiments, the fiber is more tightly woven, such as when the width of the ePTFE fiber exceeds the allotted space in the woven fabric based on the number of picks per inch and/or ends per inch. In such a fabric, there is no, or substantially no, gaps between the crossovers. The width of the ePTFE fiber may be greater than 1 times, greater than about 1 .5 times, greater than about 2 times, greater than about 3 times, greater than about 4 times, greater than about 4.5 times, greater than about 5 times, greater than about 5.5 times, or greater than about 6 times (or more) the space provided to the fibers based on the number of picks per inch and/or ends per inch. In other words, the ePTFE fibers are woven tighter than the width of the ePTFE fiber. In such embodiments, the ePTFE fibers begin the weaving process in a substantially rectangular configuration. However, due to the larger size of the fiber compared to the space provided by the picks per inch and/or ends per inch, the ePTFE fibers curl and/or fold upon themselves to conform to the weave spacing determined by the number of picks per inch and/or ends per inch of the warp and weft fibers. Generally, the folding or curling occurs in the width of the fiber such that the width of each individual fiber becomes smaller as the folding or curling of the fiber occurs. The fibers are thus in a folded configuration along a length of the fiber.

The conformability of the ePTFE fibers is schematically depicted in FIGS. 40 and 41. In FIGS. 40 and 41 , the fibers 10 are to be positioned in space (S) in a woven fabric. As shown in FIGS. 40 and 41 , the widths (W) of the fibers 10 are larger than the space (S) allotted for the fibers 10 in the woven fabric. In order to fit into the space (S) allotted for the fibers 10, the fibers 10 fold or curl into a folded configuration 15, such as is illustrated in FIG. 40.

The "foldability" or "folded configuration" of the ePTFE fibers is evidenced by a line 20 extending along the length of the fibers, as is shown in at least FIGS. 3, 5, 7, 10, 13, 16, 18, 20, 24, 26, 30, and 38. FIGS. 44 and 45, which are cross-section SEMs of an exemplary woven fabric, illustrate the conformability of the ePTFE fibers, as these figures clearly depict the folding (and/or curling) of the fiber upon itself. FIG. 41 depicts a top schematic view of the fibers in a curled configuration. The fibers may fold upon themselves in the warp and/or the weft direction. As shown in FIG. 41 , the fibers conform to fit into space (S). In a fabric including warp and weft fibers, at least one of the warp and weft fibers is in a folded configuration along, or substantially along, a length of the fiber. Thus, the ePTFE fibers fold and/or curl to a smaller width in the woven fabric. As one prophetic example, in a 88 ppi X 88 epi woven fabric and an ePTFE fiber width of 1 mm, the ePTFE fiber will fold upon itself to produce a folded width 3.5 times less than its original width in order to accommodate the space provided in the weave configuration {e.g. 88 ppi divided by 25.4 mm/1 inch is 3.5 picks per mm).

The conformability of the ePTFE fiber allows larger sized ePTFE fibers to be utilized in smaller weave spacing. Increasing the number of picks per inch and/or ends per inch compared to the width of the fiber reduces or even eliminates gaps between where the warp and weft fibers intersect. Such tightly woven fabrics are concurrently highly breathable and water resistant (e.g., have a high water entry pressure). It is to be appreciated that the fabric breathes not only through whatever gap may be present but also through the ePTFE fiber itself. Even when there are no gaps present, the woven fabric remains breathable. In contrast, conventional woven fabrics, when tightly woven, become non-breathable.

Not wishing to be bound by theory, it is believed that the conformability of the ePTFE fiber as well as the node and fibril structure enables the woven fabric to achieve many, if not all, of the features and advantages described herein. For example, the nodes of the ePTFE fiber help the fiber to maintain an "open" configuration of the fibrils when the fiber is woven. The open pores of the ePTFE fibers greatly enhance the breathability of the woven fabric. The fineness of the pores prevents water into the fiber structure while maintaining high breathability, As discussed previously, the conformability of the ePTFE fibers permits for the fibers to be woven in a tight configuration to render the woven fabric water resistant yet breathable.

Treatments may be provided to impart one or more desired functionality, such as, but not limited to, oleophobicity to the woven fabric. When provided with an oleophobic coating, such as, but not limited to, a fluoroacrylate olephobic coating, the woven fabric has an oil rating greater than or equal to 1 , greater than or equal to 2, greater than or equal to 3, greater than or equal to 4, greater than or equal to 5, or greater than or equal to 6 when tested according to the Oil Rating Test described herein. Coatings or treatments, such as a fluoroacrylate coating, may be applied to one or both sides of the woven fabric, and may penetrate through or only partially through the woven fabric. It is to be understood that any functional protective layer, functional coating, or functional membrane, such as, but not limited to, polyamides, polyesters, polyurethanes, cellophane, non-fluoropolymer membranes that are both waterproof and breathable may be attached or otherwise affixed or layered on the woven fabric, The woven fabric may be colored by a suitable colorant composition.

The ePTFE fiber has a microstructure where the pores of the ePTFE fiber are sufficiently tight so as to provide water resistance and sufficiently open to provide properties such as moisture vapor transmission and penetration by coatings of colorants. The ePTFE fiber has a surface that, when printed, provides a durable aesthetic. Aesthetic durability can be achieved in some embodiments with colorant coating compositions that comprise a pigment having a particle size that is sufficiently small to fit within the pores of the ePTFE fiber and/or within the woven fabric. Multiple colors may be applied using multiple pigments, by varying the concentrations of one or more pigments, or by a combination of these techniques. Additionally, the coating composition may be applied in any form, such as a solid, pattern, or print. A coating composition can be applied to the woven fabric by conventional printing methods. Application methods for colorizing include but are not limited to, transfer coating, screen printing, gravure printing, ink-jet printing, and knife coating.

Unlike conventional woven fabrics, the ePTFE woven fabric is able to breathe through the fibers forming the fabric (i.e. , the ePTFE fibers) as well as through the gaps formed between the ePTFE fibers during weaving. As discussed above, the ePTFE fibers have a node and fibril construction that forms passageways through the fibers that make the ePTFE fiber breathable. When the ePTFE fiber is woven, the node and fibril structure maintain open passageways. Thus, even when the ePTFE fiber is tightly woven such that there are no gaps or substantially no gaps formed in the woven structure, the ePTFE woven fabric maintains its high breathability. The ePTFE woven fabrics have a moisture vapor transmission rate (MVTR) that is greater than about 3000 g/m ² /24 hours, greater than about 5000 g/m ² /24 hours, greater than about 8000 g/m ² /24 hours, greater than about 10000 g/m ² /24 hours, greater than about 12000 g/m ² /24 hours, greater than about 15000 g/m ² /24 hours, greater than about 20000 g/m ² /24 hours, or greater than about 25000 g/m ² /24 hours when tested according to the moisture vapor transmission rate (MVTR) Test Method described herein. As used herein, the term "breathable" or "breathability" refers to woven fabrics or laminates that have a moisture vapor transmission rate (MVTR) of at least about 3000 grams/m ² /24 hours. Moisture vapor transmission, or breathability, provides cooling to a wearer of a garment, for example, made from the woven fabric. The woven fabrics also have an air permeability that is less than about 500 cfm, less than about 300 cfm, less than 100 cfm, less than about 50 cfm, less than about 25 cfm, less than about 20 cfm, less than about 15 cfm, less than about 10 cfm, less than about 5 cfm, less than about 3 cfm, and even less than about 2 cfm. It is to be understood that low air permeability correlates to improved windproofness of the fabric.

ePTFE woven fabrics described herein have a water pick-up less than or equal to about 50 g/m ² , less than or equal to 40 g/m ² , less than or equal to about 30 g/m ² , less than or equal to about 25 g/m ² , less than or equal to about 20 g/m ² , less than or equal to about 15 g/m ² , or less than or equal to about 10 g/m ² and a water entry pressure of at least about 1 kPa, at least about 1.5 kPa, at least about 2 kPa, at least about 3 kPa, at least about 4 kPa, at least about 5 kPa, or at least about 6 kPa. The ePTFE fibers restrict the entry of water into the woven fabric (into, e.g., the fiber structure and through the gaps of the woven fabric), thus eliminating problems associated with conventional woven fabrics that absorb water, which, in turn, makes the fabrics heavier, and permits for thermal conductivity of the temperature of the water through the fabric. Such thermal conductivity may be detrimental in cases where the wearer is in a cold environment and the cold is transported to the body of the wearer.

Additionally, the woven fabrics are thin and lightweight, which permits the end user to easily carry and/or transport articles formed from the woven fabrics. The woven fabrics may have a weight from about 50 g/m ² to about 500 g/m ² , from about 80 g/m ² to about 300 g/m ² , or from about 90 g/m ² to about 250 g/m ² . Additionally, the woven fabrics may have a weight per unit area of less than about 1000 g/m ² , less than about 500 g/m ² , less than about 400 g/m ² , less than about 300 g/m ² , less than about 200 g/m ² , less than about 150 g/m ² , or less than about 100 g/m ² . Further, the woven fabrics may have a height (thickness) from about 0.05 mm to about 2 mm, from about 0, 1 mm to about 1 mm, from about 0.1 mm to about 0.6 mm, from about 0.1 mm to about 0,5 mm, from about 0, 1 mm to about 0,4 mm, from about 0, 15 mm to about 0,25 mm, or from about 0, 1 mm to about 0.3 mm. The thinness of the woven fabric enables articles formed from the woven fabric to be folded compactly. The thin and light weight features also contributes to the overall comfort of the wearer of the garment, especially during movement of the wearer as the wearer experiences less restriction to movement.

Further, the woven fabrics have a soft hand and are drapable, making them suitable for use in garments, gloves, and footwear. The woven fabric has an average stiffness less than about 1000 g, less than about 500 g, less than about 400 g, less than about 300 g, less than about 250 g, less than about 200 g, less than about 150 g, less than about 100 g, and even less than about 50 g. It was surprisingly discovered that in addition to a soft hand, the woven fabrics demonstrated a reduction in noise associated with bending or folding the woven fabric. It was further discovered that even with the addition of a porous polymer membrane, as discussed hereafter, the noise was reduced, particularly when compared to conventional ePTFE laminates.

The woven fabrics are also resistant to tearing. For example, the woven fabric has a tear strength from about 10 N to about 200 N (or even greater), from about 15 N to about 150 N, or from about 20 N to about 100 N as measured by the Elemendorf Tear test described herein. Such a high tear strength enables the woven fabric to be more durable in use.

In at least one embodiment, a porous or microporous polymer membrane is laminated or bonded to the woven fabric. Non-limiting examples of porous membranes including expanded PTFE, expanded modified PTFE, expanded copolymers of PTFE, fluorinated ethylene propylene (FEP), and perfluoroalkoxy copolymer resin (PFA). Polymeric materials such as polyolefins (e.g. , polypropylene and polyethylene), polyurethanes, and polyesters are considered to be within the purview of the invention provided that the polymeric material can be processed to form porous or microporous membrane structures. It is to be appreciated that even when the inventive woven fabric is laminated or bonded to a porous or microporous membrane, the resulting laminate remains highly breathable and substantially maintains the breathability of the woven fabric, In other words, the porous or microporous membrane laminated to the woven fabric does not affect, or only minimally affects, the breathability of the woven fabric, even when laminated.

The microporous membrane may be an asymmetric membrane, As used herein, "asymmetric" is meant to indicate that the membrane structure includes multiple layers of ePTFE within the membrane where at least one layer within the membrane has a microstructure that is different from the microstructure of a second layer within the membrane. The difference between the first

microstructure and the second microstructure may be caused by, for example, a difference in pore size, a difference in node and/or fibril geometry or size, and/or a difference in density.

In a further embodiment, a textile may be attached to the microporous membrane or directly to the woven fabric. As used herein, the term "textile" is meant to denote any woven, nonwoven, felt, fleece, or knit and can be composed of natural and/or synthetic fiber materials and/or other fibers or flocking materials. For example, the textile may be comprised of materials such as, but not limited to cotton, rayon, nylon, polyester, and blends thereof. The weight of the material forming the textile is not particularly limited except as required by the application. In exemplary embodiments, the textile is air permeable and breathable.

Any suitable process for joining the membrane and/or the textile to the woven fabric (and textile to the membrane) may be used, such as gravure lamination, fusion bonding, spray adhesive bonding, and the like. The adhesive may be applied discontinuously or continuously, provided that breathability through the laminate is maintained. For example, the adhesive may be applied in the form of discontinuous attachments, such as by discrete dots or grid pattern, or in the form of an adhesive web to adhere layers of the laminate together.

The ePTFE woven fabric is suitable for use in various applications, including but not limited to garments, tents, covers, bivy bags, footwear, gloves, and the like. The woven fabric is concurrently highly breathable and water resistant. These advantageous features are achieved, at least in part, due to the high aspect ratio of the ePTFE fiber. The ePTFE woven fabric can be used alone, or it can be used in conjunction with a fluoropolymer membrane and/or textile. The surface of the ePTFE woven fabric can be colorized, for example, by printing. Additionally, the surface of the ePTFE fabric and/or the ePTFE fiber can be coated with an oleophobic coating composition to provide oleophobicity. It should be appreciated that the benefits and advantages described herein equally apply to knitted fabrics and articles as well as the woven fabrics and articles discussed herein.

TEST METHODS

It should be understood that although certain methods and equipment are described below, any method or equipment determined suitable by one of ordinary skill in the art may be alternatively utilized.

Fiber Weight per Length

A 45 meter length of fiber was obtained using a skein reel. The 45 meter length was then weighed on a scale with precision to 0.0001 grams. This weight was then multiplied by 200 to give the weight per length in terms of denier (g/9000m). This value was then multiplied by 10 and divided by 9 to give the weight per length in terms of dtex (g/10,000m).

Fiber Width

Fiber width was measured in a conventional manner utilizing a 1 Ox eye loop having gradations to the nearest 0.1 mm. Three measurements were taken and averaged to determine the width to the nearest 0.05 mm.

Fiber Thickness

Fiber thickness was measured utilizing a snap gauge accurate to the nearest 0.0001 inch. Care was taken to not to compress the fibers with the snap gauge. Three measurements were taken and averaged and then converted to the nearest 0.0001 mm.

Fiber Density

Fiber density was calculated utilizing the previously measured fiber weight per length, fiber width and fiber thickness using the following formula:

Fiber Density (g/cm ³ ) = Fiber wt per length (dtex)

Fiber Width (mm) * Fiber Thickness (mm) * 10,000 Fiber Break Strength

The fiber break strength was the measurement of the maximum load needed to break (rupture) the fiber. The break strength was measured by a tensile tester, such as an Instron ^® Machine of Canton, MA. The Instron ^® machine was outfitted with fiber (horn type) jaws that are suitable for securing fibers and strand goods during the measurement of tensile loading. The cross- head speed of the tensile tester was 25.4 cm per minute. The gauge length was 25.4 cm. Five measurements of each fiber type were taken with the average reported in units of Newtons.

Fiber Tenacity

Fiber tenacity is the break strength of the fiber normalized to the weight per length of the fiber, Fiber tenacity was calculated using the following formula:

Fiber tenacity (cN/dtex) = Fiber break strength (N) * 100

Fiber weight per length (dtex)

Fabric and Membrane Thickness

The fabric and membrane thicknesses were measured by placing either the membrane or textile laminate between the two plates of a Mitutoyo 543- 252BS Snap Gauge. The average of the three measurements was used. It is to be appreciated that the thickness of the fabric and/or the membrane may be determined by any suitable method as determined by one of skill in the art.

Matrix Tensile Strength (MTS) of Membrane

Matrix Tensile Strength of the membrane was measured using an Instron ^® 1 122 tensile test machine equipped with flat-faced grips and a 0.445 kN load cell. The gauge length was 5.08 cm and the cross-head speed was 50.8 cm/min. The sample dimensions were 2.54 cm by 15,24 cm. To ensure comparable results, the laboratory temperature was maintained between 68°F (20 °C) and 72°F (22.2 °C ) to ensure comparable results. Data was discarded if the sample broke at the grip interface. For longitudinal MTS measurements, the larger dimension of the sample was oriented in the machine, or "down web," direction. For the transverse MTS measurements, the larger dimension of the sample was oriented perpendicular to the machine direction, also known as the "cross web" direction. Each sample was weighed using a Mettler Toledo Scale Model AG204. The thickness of the samples was then measured using a Kafer FZ1000/30 snap gauge. The samples were then tested individually on the tensile tester. Three different sections of each sample were measured. The average of the three maximum load (i.e., the peak force) measurements was used.

The longitudinal and transverse MTS were calculated using the following equation:

MTS = (maximum load /cross-section area)*(bulk density of PTFE)/ density of the porous membrane), where the bulk density of PTFE is taken to be 2.2 g/cm ³ .

The average of three cross-web measurements was recorded as the longitudinal and transverse MTS.

Density of Membrane

To calculate the density of the membrane, measurements from the

Matrix Tensile Testing were used. As mentioned above, the sample dimensions were 2.54 cm by 15.24 cm. Each sample was weighed using a Mettler Toledo Scale Model AG204 and then the thickness of the samples was taken using a Kafer FZ1000/30 snap gauge. Using this data, a density of the sample can be calculated with the following formula:

m

P

w * l * t

where: p = density (g/cm ³ )

m = mass (g)

w = width (1.5 cm)

1 = length (16.5 cm)

t = thickness (cm)

The reported results are the average of three calculations. Gurley Air Flow of Membrane

The Gurley air flow test measures the time in seconds for 100 cm ³ of air to flow through a 6.45 cm ² sample at 12.4 cm of water pressure. The samples were measured in a Gurley Densometer Model 4340 Automatic Densometer. When multiple tests are performed on the same sample, care must be taken to ensure that the edges of the test areas do not overlap. (The compression that occurs to the material along the edges of the test area when it is clamped to create a seal during a Gurley test can affect the air flow results.) The reported results are the average of three measurements.

Moisture Vapor Transmission Rate Test - (MVTR)

The MVTR for each sample fabric was determined in accordance with the general teachings of ISO 15496 except that the sample water vapor transmission (WVP) was converted into MVTR moisture vapor transmission rate (MVTR) based on the apparatus water vapor transmission (WVPapp) and using the following conversion.

MVTR = (Delta P value * 24) / ( (1 /WVP) + (1 + WVPapp value) )

To ensure comparable results, the specimens were conditioned at 73.4 ± 0.4°F and 50 ± 2% rH for 2 hrs prior to testing and the bath water was a constant 73.4 ^o F ± 0.4°F.

The MVTR for each sample was measured once, and the results are reported as g/m ² /24 hours.

Mass/Area

In order to measure mass per area, fabric samples were prepared having an area of at least 100 cm ² . A Karl Schroder 100 cm ² circle cutter may be used. Each sample was weighed using a Mettler Toledo Scale Model AB204. The scale was recalibrated prior to weighing specimens, and the results were reported in grams per square meter (gsm). For membrane samples, the reported results are the average of three measurements. For printed laminate samples, the reported data is the result of a single measurement. Oil Rating Test

Oil rating of both membranes and laminates were measured. Tests were conducted following the general teachings of AATCC Test Method 1 18-1997. The oil rating number is the highest number oil which does not wet the material within a test exposure time of 30 ± 2 seconds. The reported results are the average of three measurements.

SEM Sample Preparation Method

Cross-section SEM samples were prepared by spraying them with liquid nitrogen and then cutting the sprayed samples with a diamond knife in a Leica ultracut UCT, available from Leica Microsystems, Wetzlar, Germany.

Fibril Length Measurement

The surface SEM images were used to measure fibril length. A magnification was chosen to enable the viewing of multiple fibrils, including a clear view of the points where fibrils attached to nodes. The same magnification was used for each sample that was measured. Since these node and fibril structures were irregular, 15 different fibrils, randomly distributed across each image, were identified for measurement.

To measure each fibril accurately, lines were drawn with the cursor so that they were perpendicular to the fibril on both ends where the fibril attaches to the node. The distance between the cursor drawn lines were measured, and recorded for each fibril. The results for each surface image of each sample were averaged. The reported value for fibril length represents the average of 1 5 sample measurements on the SEM image.

Liquid roof Test (Suter) and Water Pick-Up

Liquidproof testing and water pick-up was conducted as follows.

Laminates were tested for liquidproofness by using a modified Suter test apparatus with water serving as a representative test liquid. Water is forced against a sample area of about 4¼ inch (10.8 cm) diameter sealed by two rubber gaskets in a clamped arrangement. Samples are tested by orienting the sample so that the outer film surface of the sample is the surface against which water is forced. The water pressure on the sample is increased to about 0.7 psi (6.94.81 KPa) by a pump connected to a water reservoir, as indicated by an appropriate gauge and regulated by an in-line valve. The test sample was positioned at an angle, and the water was recirculated to ensure that water, not air, contacted the lower surface of the sample. The surface opposite the outer film surface of the sample was observed for a period of 3 minutes for the appearance of any water which would be forced through the sample. Liquid water seen on the surface was interpreted as a leak.

A passing (liquidproof) grade was given in cases where no liquid water is visible on the sample surface within 3 minutes. A sample was deemed

"liquidproof as used herein if it passed this test. Samples having any visible liquid water leakage, e.g. in the form of weeping, pin hole leak, etc. were not considered liquidproof and failed the test.

To determine water pick up the sample was weighed before and after the test. The difference in grams was converted to grams per square meter from a 10,8 cm diameter circle sample, thereby providing the weight increase picked up from water. The reported results are the average of three measurements.

Gap Between Fibers Measurement

Surface SEM images were used to measure the gap between fibers. A magnification was chosen to enable the viewing of at least ten fiber crossovers, including a clear view of the gaps where the fibers overlap. For each gap, the distance (D) between the fibers, at the crossovers 30 as shown in Figure 52, was measured to the nearest micrometer in the warp direction. This distance (D) was measured and averaged for at least ten crossovers within the field of view. It is to be noted that only two crossovers 30 are depicted in FIG. 52, and are for purposes of illustration only. Also, for each gap, the distance (D') orthogonal to the direction corresponding to distance between the fibers at the crossovers 30 was measured to the nearest micrometer in the fill direction. This distance D' was measured and averaged for at least ten crossovers within the field of view. The average gap distance (D) in the warp direction and the average gap distance (D') in the fill direction were reported, with the larger value reported first. Water Entry Pressure (WEP

Water entry pressure provides a test method for water intrusion through membranes and/or fabrics. A test sample is clamped between a pair of testing plates. The lower plate has the ability to pressurize a section of the sample with water, A piece of pH paper is placed on top of the sample between the plate on the non-pressurized side as an indicator of evidence for water entry. The sample is then pressurized in small increments, waiting 10 seconds after each pressure change until a color change in the pH paper indicates the first sign of water entry. The water pressure at breakthrough or entry is recorded as the Water Entry Pressure. The test results are taken from the center of test sample to avoid erroneous results that may occur from damaged edges.

Tear Strength

This test is designed to determine the average force required to propagate a single-rip tongue-type tear starting from a cut in woven fabric. A Thwing- Albert Heavy Duty Elmendorf Tearing Tester (MA1227) was used. After the instrument was calibrated and the correct pendulum weight was selected, a blinking asterisk on the left side of the display will indicate the instrument is ready for testing. The pendulum was raised to the starting position. The specimen was placed in jaws and clamped using the air clamp located on the lower right side of instrument. The air pressure was between 414 KPa and 621 KPa. The specimen was centered with the bottom edge carefully against the stops. The upper area of the specimen should be directed towards the pendulum to ensure a shearing action. The test was performed until a complete tear was achieved. The digital readout was recorded in Newtons. This was repeated until a set (1 warp and 1 weft). The reported results are the average of the measurements for one set.

Stiffness

A Thwing Albert Handle-O-Meter with a 1 OOOg beam and ¼" slot width was used to measure the hand (stiffness). A 4" x 4" sample was cut from the fabric. The specimen was placed face up on the specimen platform. The specimen was lined up so that the test direction is perpendicular to the slot to test the warp direction. The START/Test button was pressed until a click is heard, then released. The number appearing on the digital display after a second click is heard was recorded. The reading will not return to zero but will show the peak reading of each individual test. The specimen was turned over and tested again, recording the number. Then the specimen was turned 90 degrees to test the fill direction, recording the number. Finally, the specimen was turned over and tested again, recording the number. The 4 recorded numbers were added together (1 Warp Face, 1 Warp Back, 1 Fill face, 1 Fill Back) to calculate the overall stiffness of the specimen in grams. The results were reported for one sample.

Air Permeability - Frazier Number Method

Air permeability was measured by clamping a test sample in a gasketed flanged fixture which provided a circular area of approximately 6 square inches (2.75 inches diameter) for air flow measurement. The upstream side of the sample fixture was connected to a flow meter in line with a source of dry compressed air. The downstream side of the sample fixture was open to the atmosphere.

Testing was accomplished by applying a pressure of 0.5 inches of water to the upstream side of the sample and recording the flow rate of the air passing through the in-line flowmeter (a ball-float rotameter).

The sample was conditioned at 70°F (21 , 1 °C) and 65% relative humidity for at least 4 hours prior to testing.

Results are reported in terms of Frazier Number which is air flow in cubic feet/minute/square foot of sample at 0.5 inches water pressure.

Examples

Example la

A fine powder PTFE resin (Teflon 669 X, commercially available from E.I. du Pont de Nemours, Inc., Wilmington, DE) was obtained. The resin was blended with Isopar ^® K in the ratio of 0.184 g/g by weight of powder. The lubricated powder was compressed in a cylinder and allowed to dwell at room temperature for 18 hours. The pellet was then ram extruded at a 169 to one reduction ratio to produce a tape of approximately 0.64 mm thick. The extruded tape was subsequently compressed to a thickness of 0.25 mm. The compressed tape was then stretched in the longitudinal direction between two banks of rolls. The speed ratio between the second bank of rolls and the first bank of rolls, hence the stretch ratio was 1 ,4: 1 with a stretch rate of 30 %/sec. The stretched tape was then restrained and dried at 200 °C. The dry tape was then expanded between banks of heated rolls in a heated chamber at a temperature of 300 °C to a ratio of 1 ,02: 1 at a stretch rate of 0.2 %/sec, followed by an additional expansion ratio of 1 .75: 1 at a stretch rate of 46%/sec, followed by an additional expansion ratio of 1 ,02: 1 at a stretch rate of 0,5 %/sec. This process produced a tape with a thickness of 0.24 mm.

This tape was then slit to create a cross-section of 1.78 mm wide by 0.24 mm thick and having a weight per length of 3494 dtex. The slit tape was then expanded over a heated plate set to 390 °C at a stretch ratio of 6.25 : 1 with a stretch rate of 65 %/sec, This was followed by further expansion across a heated plate set to 390°C at a stretch ratio of 2.50: 1 with a stretch rate of 66 %/sec. This was followed by a further expansion across a heated plate set to 390°C at a stretch ratio of 1 .30: 1 with a stretch rate of 23 %/sec. This was followed by running across a heated plate set to 390°C at a stretch ratio of 1.00: 1 for a duration of 1.6 seconds, resulting in an amorphously locked expanded PTFE fiber.

The final amorphously locked ePTFE fiber measured 172 dtex and had a rectangular cross-section and possessed the following properties: width = 1 ,0 mm, height = 0.0356 mm, density = 0.48 g/cm ³ , break strength of 3.51 N, tenacity of 2.04 cN/dtex, and fibril length = 53.7 microns.

A scanning electron micrograph (SEM) of a side of the resulting fiber taken at l OOOx magnification is shown in FIG. 1 . FIG. 2 is a scanning electron micrograph of the top surface of the fiber taken at 1 OOOx magnification.

The fiber was then used to create a woven fabric, The weaving pattern was 2/2 twill using a thread count of 88x88 threads/inch. The woven fabric had the following properties: thickness = 0.20 mm, MVTR = 27860 g/m ² /24 hours, water pick-up = 13 gsm, hand = 71 g, tear strength - 75.6 N, WEP = 5.38 kPa, air permeability = 0.81 cfm, and oil rating = <1. A scanning electron micrograph of the surface of the fabric taken at 150x magnification is depicted in FIG. 3, A scanning electron micrograph of a side view of the fabric taken at 150x magnification is shown in FIG. 4. The length and width of the gaps between the warp and weft fibers were less than 0.01 mm. The fabric had a weight of 135 g/m ² .

A fiber (172 dtex) was removed from the woven fabric and dimensional measurements were taken of its conformed state post-weaving in order to demonstrate the conformability of the fiber. The fiber was determined to have a post-weaving folded width of 0.30 mm, a post-weaving folded height of 0.0699 mm, a post-weaving aspect ratio of 4.3, and a post-weaving density of 0.82 g/cm ³ . The pre-woven width to the post-weaving folded width ratio was 3.3 to 1.

Example lb

A fluoroacrylate coating was applied to the woven fabric of Example 1 a in order to render it oleophobic while preserving the porous and microporous structure.

The resulting oleophobic woven fabric had the following properties: thickness = 0.20 mm, MVTR = 21206 g/m ² /24 hours, water pick-up = 1 1 gsm, hand = 131 g, tear strength = 63.8 N, WEP = 6.1 1 KPa, air permeability = 1 .72 cfm, and oil rating = 6. A scanning electron micrograph of surface of the woven fabric taken at 150x magnification is shown in FIG. 5. A scanning electron micrograph of a side view of the fabric taken at 150x magnification is shown in FIG. 6. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 158 g/m ² .

Example lc

An amorphously locked ePTFE membrane was obtained having the following properties: thickness = 0.04 mm, density = 0,47 g/cc, matrix tensile strength in the strongest direction = 105.8 MPa, matrix tensile strength in the direction orthogonal to the strongest direction = 49.9 MPa, Gurley = 16.2 s, MVTR = 64168 g/m /24 hours. The woven fabric of Example l b was laminated to the ePTFE membrane in the following manner. The fabric and the ePTFE membrane were bonded together by applying a dot pattern of a melted polyurethane adhesive to the membrane. While the polyurethane adhesive dots were molten, the fabric was positioned on top of the adhesive side of the membrane. This construct (article) was allowed to cool,

The resulting article had the following properties: thickness = 0.22 mm, VTR = 12845 g/m ² /24 hours, water pick-up = 12 gsm, hand = 1 96 g, tear strength = 46.19 N, and oil rating = 6. A scanning electron micrograph of the top surface of the article taken at 150x magnification is presented in FIG. 7. A side view of the article taken at l OOx magnification is shown in FIG. 8. A side view of the article taken at lOOOx magnification is shown in FIG. 9. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 192 g/m ² .

Example Id

The woven fabric of Example l b was laminated to a plain weave nylon textile (weight of 18 g/m ² , 150 ends per inch, and 109 picks per inch, 17 dtex (5 filaments) in the following manner. The fabric and the textile were bonded together by applying a dot pattern of a melted polyurethane adhesive to the fabric. While the polyurethane adhesive dots were molten, the textile was positioned on top of the adhesive side of the fabric. This construct was allowed to cool.

The resulting article had the following properties: thickness = 0.25 mm, MVTR = 14407 g/m ² /24 hours, water pick-up = 54 gsm, hand = 288 g, tear strength = 43.18 N, WEP = 5.72; KPa, air permeability = 0.86 cfm, and oil rating = 6. A scanning electron micrograph of the top surface of the article taken at 150x magnification is presented in FIG. 10. A scanning electron micrograph of a side view of the article taken at l OOx magnification is shown in FIG. 1 1 . A scanning electron micrograph of a side view of the article taken at 500x magnification is shown in FIG. 12. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 192 g/m ² . Example le

A laminated article was constructed in the following manner. The membrane and the textile as described in Example la were bonded together by applying a dot pattern of a melted polyurethane adhesive to the membrane.

While the polyurethane adhesive dots were molten, the textile was positioned on top of the adhesive side of the fabric. This construct was allowed to cool. Next, the fabric was bonded to the membrane by applying a dot pattern of a melted polyurethane adhesive to the membrane. While the polyurethane adhesive dots were molten, the fabric was positioned on top of the membrane. This construct was allowed to cool.

The resulting article had the following properties: thickness = 0.26 mm, MVTR = 8708 g/m ² /24 hours, water pick-up = 1 1 gsm, hand = 526 g, tear strength = 37.78 N, and oil rating = 6. A scanning electron micrograph of the top surface of the article taken at 150x magnification is shown in FIG. 13. A scanning electron micrograph of a side view of the article taken at l OOx magnification is shown in FIG. 14. A scanning electron micrograph of a side view of the article taken at 300x magnification is shown in FIG. 15. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 216 g/m ² .

Example 2a

A woven fabric was constructed in the same manner as described in Example l a with the exception that the weave pattern was a plain weave. The woven fabric had the following properties: thickness = 0.15 mm, MVTR =

21336 g/m ² /24 hours, water pick-up = 4 gsm, hand = 83 g, oil rating = <1 , WEP = 3.13 KPa, air permeability = 0.44 cfm, and tear strength = 36,3 N. A scanning electron micrograph of the top surface of the fabric taken at 150x magnification is shown in FIG. 16. A scanning electron micrograph of a side view of the article taken at 250x magnification is shown in FIG, 17. The length and width of the gaps between the fibers were about 0.01 mm and 0.01 mm, respectively. The fabric had a weight of 142 g/m ² . A fiber (172 dtex) was removed from the woven fabric and dimensional measurements were taken of its conformed state post-weaving in order to demonstrate the conformability of the fiber. The fiber was determined to have a post-weaving folded width of 0.25 mm, a post-weaving folded height of 0.0736 mm, a post-weaving aspect ratio of 3.4, and a post-weaving density of 0.94 g/cm ³ . The pre-woven width to the post-weaving folded width ratio was 4.0 to 1.

Example 2b

The woven fabric of Example 2a was rendered oleophobic in the same manner as described in Example lb.

The oleophobic woven fabric had the following properties: thickness = 0.16 mm, MVTR = 13265 g/m ² /24 hours, water pick-up = 7 gsm, hand = 141 g, tear strength = 30.3 N, WEP = 4.01 KPa, Air permeability = 0.49 cfm, and oil rating = 6. A scanning electron micrograph of the top surface of the fabric taken at 150x magnification is presented in FIG. 18. A scanning electron micrograph of a side view of the fabric taken at 250x magnification is shown in FIG. 19. The length and width of the gaps between the fibers were about 0.01 mm and 0.02 mm, respectively. The fabric had a weight of 158 g/m ² .

Example 2c

An oleophobic laminated article was constructed in the following manner. The membrane and the textile were bonded together by applying a dot pattern of a melted polyurethane adhesive to the membrane. While the polyurethane adhesive dots were molten, the textile was positioned on top of the adhesive side of the fabric. This construct was allowed to cool. Next, the fabric was bonded to the membrane by applying a dot pattern of a melted polyurethane adhesive to the membrane. While the polyurethane adhesive dots were molten, the fabric was positioned on top of the membrane. This construct was allowed to cool.

The resulting article had the following properties: thickness = 0.24 mm, MVTR = 8274 g/m ² /24 hours, water pick-up = 10 gsm, hand = 465 g, tear strength = 20.59 N, and oil rating = 6. A scanning electron micrograph of the top surface of the article taken at 150x magnification is presented in FIG. 20. A scanning electron micrograph of a side view of the article taken at 250x magnification is shown in FIG. 21. The length and width of the gaps between the fibers were about 0.01 mm and 0,03 mm, respectively. The fabric had a weight of 214 g/m ² .

Example 3a

A tape was produced in the same manner as described in Example l a. This tape was then slit to create a cross-section of 1 .14 mm wide by 0.24 mm thick and having a weight per length of 2184 dtex. The slit tape was then expanded across a heated plate set to 390°C at a stretch ratio of 6.00: 1 with a stretch rate of 70 %/sec. This was followed by expansion across a heated plate set to 390 °C at a stretch ratio of 2,50: 1 with a stretch rate of 74 %/sec. This was followed by a further expansion across a heated plate set to 390°C at a stretch ratio of 1 ,30: 1 with a stretch rate of 26 %/sec. This was followed by running across a heated plate set to 390 °C at a stretch ratio of 1.00: 1 for a duration of 1.4 seconds resulting in an amorphously locked expanded PTFE fiber.

The amorphously locked ePTFE fiber measured 1 12 dtex and had a rectangular cross-section and possessed the following properties: width = 0.7 mm, height = 0.0356 mm, density = 0.45 g/cm3, break strength of 2.14 N, tenacity of 1 .92 cN/dtex, and fibril length = 57.2 microns.

A scanning electron micrograph of the fiber taken at 1 OOOx

magnification is shown in FIG. 22. A scanning electron micrograph of a side view of the fiber taken at l OOOx magnification is shown in FIG. 23.

The fiber was used to create a woven fabric. The weaving pattern was 2/2 twill and a thread count of 100 xl OO threads/inch. The woven fabric had the following properties: thickness = 0.15 mm, MVTR = 32012 g/m ² /24 hours, water pick-up = 21 gsm, hand = 47 g, oil rating = <1 , WEP = 2.15 Pa, air permeability = 1.17 cfm, and tear strength = 57.8 N. A scanning electron micrograph of the woven fabric taken at 150x magnification is shown in FIG, 24, A scanning electron micrograph of a side view of the fabric taken at 200x magnification is shown in FIG. 25. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 102 g/m ² .

A fiber (1 12 dtex) was removed from the woven fabric and dimensional measurements were taken of its conformed state post-weaving in order to demonstrate the conformability of the fiber. The fiber had a post-weaving folded width of 0.25 mm, a post-weaving folded height of 0.0559 mm, a post- weaving aspect ratio of 4,5, and a post-weaving density of 0.80 g/cm ³ , The pre- woven width to the post-weaving folded width ratio was 2.8 to 1 . Example 3b

The woven fabric of Example 3a was rendered oleophobic in the same manner as described in Example l b. This article had the following properties: thickness = 0.15 mm, MVTR = 20526 g/m ² /24 hours, water pick-up = 15 gsm, hand = 86 g, tear strength = 48.2 N, WEP = 5.45 KPa, air permeability = 1 .85 cfm, and oil rating = 6. A scanning electron micrograph of the fabric taken at 150x magnification is shown in FIG. 26. A scanning electron micrograph of a side view of the fabric taken at 200x magnification is shown in FIG. 27. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 120 g/m ² .

Example 4

A fine powder PTFE resin (Teflon 669 X, commercially available from E.I. du Pont de Nemours, Inc., Wilmington, DE) was obtained. The resin was blended with Isopar ^® in the ratio of 0.184 g/g by weight of powder. The lubricated powder was compressed in a cylinder and placed in an oven at a temperature of 49 °C for 1 8 hours. The pellet was then ram extruded at a 169 to one reduction ratio to produce a tape of approximately 0.64 mm thick. The extruded tape was subsequently compressed to a thickness of 0.25 mm. The compressed tape was then stretched in the longitudinal direction between two banks of rolls. The speed ratio between the second bank of rolls and the first bank of rolls, hence the stretch ratio was 1 .4: 1 with a stretch rate of 30 %/sec. The stretched tape was then restrained and dried at 200 °C. The dry tape was then expanded between banks of heated rolls in a heated chamber at a temperature of 300 °C to a ratio of 1.02: 1 at a stretch rate of 0.2 %/sec, followed by an additional expansion ratio of 1 .75: 1 at a stretch rate of 46%/sec, followed by an additional expansion ratio of 1.02: 1 at a stretch rate of 0.5 %/sec. This process produced a tape with a thickness of 0.24 mm thick.

This tape was then slit to create a cross-section of 1.14 mm wide by 0,24 mm thick and having a weight per length of 2373 dtex. The slit tape was then expanded across a heated plate set to 390 °C at a stretch ratio of 6.00: 1 with a stretch rate of 69 %/sec. This was followed by further expansion across a heated plate set to 390 °C at a stretch ratio of 2.20: 1 with a stretch rate of 32 %/sec. This was followed by a further expansion across a heated plate set to 390 °C at a stretch ratio of 1.40: 1 with a stretch rate of 19 %/sec. This was followed by a further expansion across a heated plate set to 390 °C at a stretch ratio of 1 .20: 1 with a stretch rate of 12 %/sec. This was followed by running across a heated plate set to 390 °C at a stretch ratio of 1 .00: 1 for a duration of 2.1 seconds, resulting in an amorphously locked expanded PTFE fiber.

The final amorphously locked ePTFE fiber measured 107 dtex and had a rectangular cross-section and possessed the following properties: width = 0.45 mm, height = 0.0279 mm, density = 0.85 g/cm ³ , break strength of 3.20 N, tenacity of 3.01 cN/dtex, and fibril length = 16.1 microns.

A scanning electron micrograph of the top surface of the fiber taken at l OOOx magnification is shown in FIG. 28. FIG. 29 is a scanning electron micrograph of a side view of the fiber taken at l OOOx magnification.

The fiber was used to create a woven fabric. The weaving pattern was 2/2 twill and a thread count of 100x100 threads/inch, The woven fabric had the following properties: thickness = 0.13 mm, MVTR = 28497 g/m ² /24 hours, water pick-up = 5 gsm, hand = 72 g, oil rating = < 1 , WEP = 1.96 Pa, Air permeability = 2.4 cfm, and tear strength = 71 .2 N. A scanning electron micrograph of the top surface of the fabric taken at 150x magnification is shown in FIG. 30. A side view of the fabric taken at 150x magnification is shown in FIG. 31. The length and width of the gaps between the fibers were less than 0.01 mm. The fabric had a weight of 93 g/m ² .

A fiber (107 dtex) was removed from the woven fabric and dimensional measurements were taken of its conformed state post-weaving in order to demonstrate the conformability of the fiber. The fiber had a post-weaving folded width of 0.25 mm, a post-weaving folded height of 0,0356 mm, a post- weaving aspect ratio of 7.0, and a post-weaving density of 1 .20 g/cm ³ . The pre- woven width to the post-weaving folded width ratio was 1 .8 to 1.

Example 5

A tape was produced in the same way as in Example l a. This tape was then slit to create a cross-section of 4.57 mm wide by 0.236 mm thick and having a weight per length of 7937 dtex. The slit tape was then expanded across a heated plate set to 390 °C at a stretch ratio of 6.00: 1 with a stretch rate of 70 %/sec. This was followed by another expansion across a heated plate set to 390°C at a stretch ratio of 2.50: 1 with a stretch rate of 74 %/sec. This was followed by a further expansion across a heated plate set to 390 °C at a stretch ratio of 1 .30: 1 with a stretch rate of 26 %/sec. This was followed by running across a heated plate set to 390°C at a stretch ratio of 1 .00: 1 for a duration of 1.4 seconds, resulting in an amorphously locked expanded PTFE fiber.

The amorphously locked ePTFE fiber measured 452 dtex and had a rectangular cross-section and possessed the following properties: width = 2.2 mm, height = 0.0406 mm, density = 0.51 g/cm3, break strength of 1 1 .48 N, tenacity of 2.55 cN/dtex, and fibril length = 60 microns. A scanning electron micrograph of the fiber surface taken at l OOOx magnification is shown in FIG. 36. A scanning electron micrograph of a side view of the fiber taken at l OOOx magnification is shown in FIG. 37.

The weaving pattern was a plain weave and had a thread count of 50 x 50 threads/inch (19.7 x 19.7 threads/cm). The ratio of the pre-woven fiber width to the calculated allotted space per fiber within the weave pattern was 4.3 to 1 . The woven fabric had the following properties: thickness = 0.24 mm, MVTR = 14798 g/m ² /24 hours, water pick-up = 15 gsm, hand = 281 g, oil rating = <1 , WEP = 1.86 kPa, air permeability = 2.1 cfm. A scanning electron micrograph of the woven fabric taken at 150x magnification is shown in FIG. 38. A scanning electron micrograph of a side view of the fabric taken at 1 50x magnification is shown in FIG. 39. The length and width of the gaps between the fibers were about 0.04 mm and 0.01 mm, respectively. Scanning electron micrographs of the top surface of the fabric taken at 120x magnification depicting the gap width measurements in the horizontal direction and the gap width measurements in the vertical direction are shown in FIGS. 40 and 41 , respectively. The fabric had a weight of 21 1 g/m ² .

A fiber (452 dtex) was removed from the woven fabric and dimensional measurements were taken of its conformed state post-weaving in order to demonstrate the conformability of the fiber. The fiber had a post-weaving folded width of 0.40 mm, a post-weaving folded height of 0.1524 mm, a post- weaving aspect ratio of 2.6, and a post-weaving density of 0.74 g/cm ³ . The pre- woven width to the post-weaving folded width ratio was 5.5 to 1.

Example 6

A woven fabric was constructed in the same manner as described in Example 5 with the exception that the plain weave pattern had a thread count of 40 x 40 threads/inch (15.7 x 15.7 threads/cm). The woven fabric had the following properties: thickness = 0.25 mm, MVTR = 27846 g/m ² /24 hours, water pick-up = 7 gsm, hand = 71 g, oil rating = <1 , WEP = 1 .69 Pa, and air permeability = 3.87 cfm. A scanning electron micrograph of the top surface of the fabric taken at 150x magnification is shown in FIG. 42. A scanning electron micrograph of a side view of the fabric taken at 150x magnification is shown in FIG. 43. Scanning electron micrographs of side views of the fabric taken at 300x and 400x magnifications are shown in FIGS. 44 and 45, respectively. FIG. 45 clearly depicts the conforming of the fiber to the weave spacing, as the fiber has folded upon itself.

The length and width of the gaps between the fibers were about 0.08 mm and 0.02 mm, respectively. The fabric had a weight of 157 g/m ² .

A fiber (452 dtex) was removed from the woven fabric and dimensional measurements were taken of its conformed state post-weaving in order to demonstrate the conformability of the fiber. The fiber had a post-weaving folded width of 0.50 mm, a post-weaving folded height of 0.1219 mm, a post- weaving aspect ratio of 4.1 , and a post-weaving density of 0.74 g/cm ³ . The pre- woven width to the post-weaving folded width ratio was 4.4 to 1 . Comparative Example 1

An ePTFE fiber by W.L. Gore & Associates (part number VI 1 1776, W.L. Gore & Associates, Inc., Elkton, MD) was obtained. The ePTFE fiber measured 1 1 1 dtex and had a rectangular cross-section and possessed the following properties: width = 0.5 mm, height = 0.01 14 mm, density = 1 .94 g/cm ³ , break strength = 3.96 N, tenacity = 3.58 cN/dtex, and fibril length = indeterminate (no visible nodes to define an endpoint for the fibrils). A scanning electron micrograph of the top surface of the fiber taken at l OOOx magnification is shown in FIG. 32. A scanning electron micrograph of a side view of the fiber taken at l OOOx magnification is shown in FIG. 33.

In order to successfully weave this fiber, it was twisted at 315 turns/meter. This twisted fiber was then woven into a fabric using a 2/2 twill pattern and a thread count of 100x100 threads/inch.

The woven fabric had the following properties: thickness = 0, 12 mm, MVTR = 36756 g/m ² /24 hours, water pick-up = 4 gsm, hand = 102 g, WEP = 0.39 kPa, air permeability = 367 cfm, and oil rating = < 1 . A scanning electron micrograph of the top surface of the fabric taken at 1 50x magnification is shown in FIG. 34. A scanning electron micrograph of a side view of the fabric taken at 1 0x magnification is shown in FIG. 35. The length and width of the gaps between the fibers were about 0.09 mm and 0, 12 mm, respectively. The fabric had a weight of 94 g/m ² .

Comparative Example 2

A non-microporous commercially available ePTFE fiber available from W.L. Gore & Associates (part number V I 12961 , W.L. Gore & Associates, Inc., Elkton, MD) was obtained. The ePTFE fiber measured 457 dtex and had a rectangular cross-section and possessed the following properties: width = 0,6 mm, height = 0.0419 mm, density = 1.82 g/cm ³ , break strength = 18.33 N, tenacity = 4.03 cN/dtex, and fibril length = indeterminate (no visible nodes to define an endpoint for the fibrils). A scanning electron micrograph of the top surface of the fiber taken at l OOOx magnification is shown in FIG. 46. A scanning electron micrograph of a side view of the fiber taken at 1 OOOx magnification is shown in FIG. 47. In order to successfully weave this ePTFE fiber, it was twisted at 1 18 turns/meter. This twisted fiber was then woven into a fabric using a plain weave pattern and a thread count of 50X50 threads/inch.

The woven fabric had the following properties: thickness = 0,21 mm, MVTR = 1 1659 g/m ² /24 hours, water pick-up = 10 gsm, hand = 380 g, WEP = 0.49 kPa, air permeability = 70 cfm, and oil rating = < 1 . A scanning electron micrograph of the top surface of the fabric taken at 150x magnification is shown in FIG. 48. A scanning electron micrograph of a side view of the fabric taken at 150x magnification is shown in FIG. 49. The length and width of the gaps between the fibers were about 0.1 1 mm and 0.08 mm, respectively. The fabric had a weight of 201 g/m ² .

Comparative Example 3

A commercially available ePTFE fiber available from W.L. Gore & Associates (part number V I 12961 , W.L. Gore & Associates, Inc., Elkton, MD) was obtained. The ePTFE fiber measured 457 dtex and had a rectangular cross- section and possessed the following properties: width = 0.6 mm, height = 0.0419 mm, density = 1.82 g/cm ³ , break strength = 18.33 N, tenacity = 4.03 cN/dtex, and fibril length = indeterminate (no visible nodes to define an endpoint for the fibrils). A scanning electron micrograph of the top surface of the fiber taken at l OOOx magnification is shown in FIG. 46. A side view of the fiber taken at l OOOx magnification is shown in FIG. 47.

In order to successfully weave this ePTFE fiber, it was twisted at 138 turns/meter. This twisted fiber was then woven into a fabric using a plain weave pattern and a thread count of 64X64 threads/inch.

The woven fabric had the following properties: thickness = 0.24 mm, MVTR = 7840 g/m ² /24 hours, water pick-up = 9 gsm, hand = 698 g, WEP = 1.12 kPa, air permeability = 26 cfm, and oil rating = < 1 . A scanning electron micrograph of the top surface of the fabric taken at 1 50x magnification is shown in FIG. 50. A side view of the fabric taken at 150x magnification is shown in FIG. 51 . The length and width of the gaps between the fibers were about 0.07 mm and 0.02 mm, respectively, The fabric had a weight of 261 g/m ² . The invention of this application has been described above both generically and with regard to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations of the invention can be made without departing from the spirit or scope of the invention, as defined in the appended claims.