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[0001] This non-provisional application claims the benefit under Title 35, U.S.C. §119(e) of co-pending U.S. provisional application serial No. 60/229,242, filed, Aug. 30, 2000; co-pending U.S. provisional application serial No. 60/229,708, filed, Aug. 31, 2000; co-pending U.S. provisional application entitled WOVEN FABRICS FORMED FROM INTIMATE BLENDS OF GREATER THAN ONE TYPE OF FIBER, by Charles A. Howland, filed, Aug. 20, 2001, serial No. 60/313,835; and co-pending U.S. provisional application entitled FABRICS FORMED FROM INTIMATE BLENDS OF GREATER THAN ONE TYPE OF FIBER, by Charles A. Howland, filed, Aug. 22, 2001, serial number not yet assigned, each incorporated herein by reference.
[0002] The present invention is directed to methods for improving the dyeabiity, printability, and/or puncture resistance of fabrics comprising high tenacity fibers having a tensile breaking strength of at least about 10 g/Denier, and fabrics produced by or treated by the methods.
[0003] A wide variety of natural and synthetic fabrics are known in the prior art for constructing sportswear, rugged outerwear, protective clothing, etc. (for example, gloves, aprons, chaps, pants, boots, gators, shirts, jackets, coats, socks, shoes, undergarments, vests, waders, hats, gauntlets, etc.). Typically, vestments designed for use as rugged outerwear have been constructed of relatively loosely-woven fabrics made from natural and/or synthetic fibers having a relatively low strength or tenacity (for example, cotton, polyesters, polyacrylics, polypropelene, etc.), with each fiber having a tensile strength or tenacity of less than about 8 g/Denier (gpd)), more typically less than about 5 gpd, and in some cases below about 3 gpd. While such materials can have a variety of beneficial properties, for example, dyeability, breathability, lightness, comfort, and in some instances, abrasion-resistance, such low-strength, low cover materials typically have poor puncture, tear, and cut resistance. Although the fabric design has a great deal to do with the performance of the materials.
[0004] In addition, a variety of high-strength materials for producing yarns and fabrics have also been employed in the prior art for applications involving ballistic armor, industrial, military, or law enforcement protective gear, and the like to provide enhanced puncture, cut, and tear resistance. Such materials have typically been fabricated from continuous filament yarns consisting of filaments of polymeric materials having a tensile strength or tenacity greater than about 10 g/Denier, and more typically greater than 15 g/Denier (referred to hereinafter as “high strength,” “high tensile strength,” “high tenacity,” or “performance” materials or fibers). One popular class of polymers for producing such fabrics are the para-aramids, for example, KEVLAR™, TWARON™, and TECHNORA™. Other examples of high strength materials utilized in the prior art for fabricating ballistic and protective fabrics include liquid crystal polyesters (e.g. VECTRAN™), ultra-high molecular weight polyethylenes (e.g. SPECTRA™), and poly (p-phenylene-2,6-benzobisoxazole) (PBO)(e.g. ZYLON™). However, fabrics fabricated from such high-strength materials have typically been limited in use to industrial, military, or police applications involving the formation of puncture-resistant and/or antiballistic devices, shields, body armor, and similar articles. The fabrics constructed from the above-mentioned high strength materials have not been typically employed for fabricating articles of clothing for use as rugged outerwear or sportswear, for example, for use in clothing and other articles of apparel designed for activities such as hiking, hunting, fishing, gardening, participation in contact sports, etc.
[0005] There are a variety of reasons why puncture-resistant materials constructed from the above-mentioned high strength materials in forms in which they are typically available have not been typically employed in fabrication of rugged outerwear and other vestments designed and produced for use as casual, sporting, or outdoor outerwear. To begin with, each of the above-mentioned materials tends to be difficult or essentially impossible to dye, color, or print effectively, thereby substantially limiting the color and design options of the articles of apparel constructed from such materials. In addition, the above-mentioned materials, while having outstanding tensile strength characteristics, often have relatively poor abrasion resistance, which is undesirable in articles of clothing designed for use as rugged outerwear or sportswear. Also, filaments of such materials can be difficult to form into small diameter, light weight yarns. Typical yarn sizes commercially available greatly exceed the size and weight of commercially available yarns formed of natural or synthetic non-high tenacity materials, thereby limiting the ability to form lightweight woven fabrics and articles of apparel from such commercially available high tenacity yarns. Finally, the above-mentioned high tenacity materials tend to be very expensive and more difficult to process and weave into fabrics having characteristics desirable or suitable for use as rugged outerwear (with the notable exception of high puncture, cut, and tear resistance) than the more typically employed natural and/or synthetic materials mentioned above having a lower tensile strength.
[0006] There remains a need in the art to provide fabrics, fabric systems, and yarns/fiber bundles useful and economical for constructing rugged outerwear and recreational articles of apparel having a higher degree of puncture, tear and cut resistance than typically available, which puncture, tear and cut resistance is useful to prevent against injury to a wearer due to typically-encountered assaults while participating in use of outerwear, for example, exposure to thorns, snake bite, sharp branches, etc., while also maintaining certain, or essentially all, of the desirable properties of currently-employed non-high tenacity fiber-based fabrics, for example, dyability, printability, comfort, abrasion resistance, low cost, softness, quietness, breathability, light weight, etc. The present disclosure describes inventive fabrics, fabric constructions, and fabric systems, which can, in certain embodiments include one or more high tenacity fiber types, providing enhanced puncture, cut, and/or tear resistance, while also retaining some or all of the desirable aesthetic, comfort, and wearability characteristics of conventional rugged outerwear fabrics.
[0007] A variety of methods of improving the dyeability and printability of fabrics comprising or consisting essentially of high tenacity fibers having a tensile breaking strength of at least about 10 g/Denier are disclosed. Such methods can result in fabrics, yarns, and/or fiber bundles having an improved ability to be dyed and/or printed with a printed pattern (e.g., a camouflage pattern), when compared to typical high tenacity fiber-based fabrics known in the prior art. The fabrics can have dyeability characteristics enabling them to be dyed with a variety of commercially relevant fabric dyes, such that the fabrics, after exposure to the dyes, are characterized by an essentially visually uniform dyed color density. In one embodiment, a dyeable fiber bundle, which can be utilized to form dyeable yarns and fabrics, which comprises at least about 5% of high tenacity fibers having a tensile breaking strength of at least about 10 g/Denier is disclosed. Also disclosed is a method for pre-washing roll stock of fabrics comprising or consisting essentially of high tenacity fibers in order to improve the level of cut, puncture, or tear resistance of the fabrics subsequent to the pre-wash and before assembly of the fabrics into articles of apparel. A variety of fabrics including high tenacity fibers having a tensile breaking strengths of at least about 10 g/Denier, as produced by or treated by such methods are also disclosed.
[0008] In one aspect, an article is disclosed. The article comprises a fiber bundle formed of a plurality of fibers, at least about 5% of the plurality of fibers comprising fibers having a tensile breaking strength of at least about 10 g/Denier. The fiber bundle is constructed such that upon exposure to a fabric dye, the fabric bundle is dyed to an essentially visually uniform color density.
[0009] In another aspect, a series of methods are disclosed. In one embodiment, a method is disclosed comprising the step of dyeing a fiber bundle formed of a plurality of fibers, at least about 5% of a plurality of fibers comprising high tenacity fibers having a tensile breaking strength of at least about 10 g/Denier, with a fabric dye to form a dyed fiber bundle having an essentially visually uniform dye color density.
[0010] In another embodiment, a method is disclosed comprising a step of pre-washing roll stock of a fabric that includes at least one fiber of a first type having a tensile breaking strength of at least about 10 g/Denier. The method further comprising a step of increasing the puncture resistance of the fabric in comparison to the puncture resistance of the fabric prior to treatment in the pre-washing step.
[0011] Other advantages, novel features, and objects of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings, which are schematic and which are not intended to be drawn to scale. In the figures, each identical or nearly identical component that is illustrated in various figures is represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention.
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[0024] The present disclosure describes a variety of fabric systems and novel fabrics, yarns, and fiber bundles for use in forming protective fabrics, especially for use in applications such as sporting apparel and rugged outerwear. The below disclosed fabrics and fabric systems each, preferably, include a puncture, cut, and tear resistant layer (hereinafter referred to as a “puncture-resistant layer) providing protection against commonly encountered hazards, such as thorns, branches, snake bite, sharp rocks, etc. A variety of inventive solutions to the above-mentioned need in the prior art to provide fabrics and fabric systems able to provide enhanced puncture, cut, and tear resistance (for example, similar or essentially identical to that provided by industrial fabrics and materials consisting of high tenacity fibers), while maintaining one or more desirable properties of outerwear fabricated from traditional materials for fabricating such fabrics, such as natural fibers and/or low tenacity synthetic (e.g. dyeability, printability, soft hand, breathability, light weight, abrasion resistance, etc.). In one aspect, the disclosure describes protective fabric layers formed from intimate blends of two or more different fiber types. As discussed below, in certain preferred embodiments, such intimate blend fabrics preferably include at least one fiber type that is a high tenacity fiber having a tensile breaking strength of at least about 10 g/Denier and also include at least one other fiber type that is a non-high tenacity (i.e. with a tensile breaking strength less than about 10 g/Denier) natural or synthetic fiber, for example of the type traditionally employed in the manufacture of rugged outerwear (e.g., cotton, polyester, polyacrylic, polyolefin, etc.). As discussed in more detail below, such intimate blend fabrics can combine the beneficial attributes of each of the fibers comprising the intimate blend to produce, for example, an intimate blend fabric having an increased level of puncture, cut, and tear resistance, while maintaining one or more of the above-mentioned desirable properties of the non-high tenacity fiber-based fabrics.
[0025] In another aspect, the disclosure describes puncture-resistant fabric layers comprising woven fabrics with unique woven structures. For example, in one embodiment, such a fabric layer comprises a high cover factor (defined below) woven fabric comprising a plurality of fill yarns and a plurality of warp yarns, wherein the weight per unit length (in Denier) of the fill yarns is less than that of the warp yarns, or, equivalently, the of the length per unit weight (for example, in Cotton Count or Worsted Count) of the fill yarns is greater than that of the warp yarns. Such a construction is particularly preferred for fabrics consisting essentially of high tenacity fibers. Such high cover, small fill yarn construction enables such fabrics to be woven to have a decreased overall weight per unit surface area and improved tensile balance (explained below). Also disclosed within the context of this aspect of the invention are various preferred techniques for forming lightweight yarns consisting essentially of high tenacity fibers for comprising the small fill yarns and/or warp yarns of the above-described small fill, high cover factor woven fabrics. In other embodiments, beneficial attributes of both the intimate blend fabrics and the high cover and/or small fill woven construction can be combined, or, alternatively, the high cover, small fill construction can be utilized with non-high tenacity fibers to improve the tightness of the weave and puncture, cut, and tear resistance of fabrics woven from yarns consisting of non-high tenacity fibers.
[0026] In yet another aspect, the disclosure describes a variety of embodiments of layered and laminated fabric systems, each, preferably, including a puncture-resistant layer, preferably comprising or consisting essentially of high tenacity fibers, in combination with one or more additional layers providing one or more desirable attributes of an article of apparel for use in, for example, rugged outerwear (e.g., dyeability, printability, soft hand, breathability, abrasion resistance, etc.). In such embodiments, puncture-resistant layers comprising intimate blends and/or high cover/small fill fabrics, as described above and in more detail below, can be utilized, or, in other embodiments, other novel and/or conventionally constructed puncture-resistant layers can be utilized in combination with one or more additional layers to achieve an overall system having a desirable set of performance properties.
[0027] Finally, as described in more detail below, many of the above-mentioned novel fabrics and fabric systems comprising or consisting essentially of high tenacity fibers can have an improved ability to be dyed and/or printed with a printed pattern (e.g., as one example, a camouflage pattern), when compared to typical high tenacity fabrics known in the prior art. Also disclosed is a method for pre-washing fabrics comprising or consisting essentially of high tenacity fibers in order to improve the level of cut, puncture, or tear resistance of the fabrics, subsequent to the prewash and before assembly of the fabrics into articles of apparel.
[0028] Intimate Blend Fabrics, Yarns, and Fiber Bundles
[0029] The present invention provides a number of intimate blend fabrics useful for applications involving articles of apparel utilized for rugged outerwear and sporting wear, in which improved puncture, cut, and tear resistance is desired over typical articles of apparel for such purposes known in the prior art. An “intimate blend fabric” as used herein refers to a fabric including therein at least two different types of fibers, and in some instances a plurality of different types of fibers, wherein the different types of fibers are each present in a single layer of the fabric (or in at least one single layer of the fabric system for fabric systems having multiple layers), such that each fiber type is in direct and intimate contact with fibers of at least one other type within the fabric layer. An “intimate blend” yarn or fiber bundle, similarly refers to a yarn or fiber bundle including therein at least two different types of fibers, and in some instances a plurality of different types of fibers, such that each fiber type is in direct and intimate contact with fibers of at least one other type within the yarn or fiber bundle.
[0030] The term “fiber” as used herein refers to an elongate, individual and essentially monolithic unit of matter, either natural or synthetic, that forms the basic element of a fabric. The term “filament” as used herein refers to a fiber of an indefinite or extreme length. The term “staple fiber” as used herein refers to fibers having a shorter length (less than about 40 inches and typically between about 1 inch and about 4 inches), such fibers either normally having such a length (e.g. many natural fibers) or being cut or stretch broken from filaments. A “fiber bundle” as used herein refers to a plurality of fibers and/or filaments grouped together to form a multi-fiber strand bundle. A “yarn” as used herein refers to any continuous strand of fibers or filaments in a form suitable for knitting, weaving, or otherwise intertwining to form a textile fabric including, but not limited to: a number of fibers twisted together into a single fiber bundle (single ply spun yarn); a number of filaments laid together without twist (a zero-twist yarn); a number of filaments laid together with a degree of twist; a single filament with or without twist (a monofilament yarn); and two or more fiber bundles twisted together (a plied yarn or multi-ply yarn). A “woven fabric” as used herein refers to a fabric characterized by intersecting warp and fill yarns interlaced so that they cross each other at essentially right angles, the term including, but not limited to, well known woven structures such as plain weave (including variations thereof such as basket weaves), twill weaves, and satin weaves.
[0031] As one example, in one construction, an intimate blend fabric can comprise a woven fabric having a plurality of fill yarns and a plurality of warp yarns, wherein at least one of the fill yarns comprises fibers of a first type and wherein at least one of the warp yarns comprises fibers of a second fiber type. In such constructions, a variety of possibilities for weaving together fill yarns and warp yarns formed of the first and second fiber types, respectively, is possible; for example, each of the fill yarns can consist essentially of fibers of the first type and each of the warp yarns can consist essentially of fibers of the second type. Alternatively, yarns consisting essentially of fibers of the first type and yarns consisting essentially of fibers of the second type can be alternated in each of the warp and fill directions such that some yarns of the fill are yarns consisting essentially of fibers of the first type, other yarns of the fill are yarns consisting essentially of fibers of the second type, some yarns in the warp are yarns consisting essentially of fibers of the first type and other yarns in the warp are yarns consisting essentially of fibers of the second type. In such a configuration the yarns could individually alternate, be grouped into groups of two, three, four, etc., or be interwoven in any other of the wide variety of possible permutations, which would be readily envisioned by those of ordinary skill in the art.
[0032] In other embodiments, the fabric can comprise a woven fabric, in which some, or each, of the yarns in one or both of the fill and warp directions can comprise a plied yarn formed of two or more individual fiber bundles twisted together to form the plied yarn. In such embodiments, an intimate blend fabric can be formed by forming one or more of a first fiber bundle comprising or consisting essentially of fibers of a first type with one or more of a second fiber bundle comprising or consisting essentially of fibers of a second type into an intimate blend plied yarn, which is subsequently woven to form the intimate blend fabric. As should be readily understood, for intimate blends involving more than two types of fibers, in each of the above-mentioned constructions additional yarns and/or fiber bundles including a third, fourth, fifth, etc. fiber type could be included and blended together and/or with the above-mentioned yarns and fiber bundles to form a more complex intimate blend fabric.
[0033] In one particularly preferred embodiment, the intimate blend fabrics are produced from a plurality of yarns, at least one of which, and preferably at least each of those in the warp or fill direction (in a woven fabric), or in other embodiments, each of which in both the warp and fill directions, are formed of fiber bundles that comprise fibers of at least a first fiber type and a second fiber type. In such embodiments, the fiber bundles themselves, which form or are used to form one or more of the yarns utilized to construct the fabric layer, for example by weaving, can comprises an intimate blend of two or more different fiber types.
[0034] As discussed in more detail below, preferred embodiments of the intimate blend fabrics involve fabric layers constructed of two or more different types of fibers, most preferably where at least one fiber type is a high tenacity fiber having a tensile breaking strength of at least about 10 g/Denier and at least one other fiber type is a natural or synthetic fiber having a tensile breaking strength of less than about 10 g/Denier. In preferred embodiments, the non-high tenacity fibers are selected based on their possessing one or more desirable properties, for example, dyability, printability, softness, flexibility, the ability to improve the spinnability of staple fibers into fiber bundles/yarns, etc.
[0035] “High tenacity fibers” as used herein are those having a tensile breaking strength of at least about 10 g/Denier, more preferably at least about 15 g/Denier, in some embodiments at least about 20 g/Denier, in other embodiments at least about 25 g/Denier and in yet other embodiments at least about 30 g/Denier. Such high tenacity fibers are known in the art, but have typically been limited in use to industrial protective articles or antiballistic material. In addition, typically fabrics made from such materials have been made essentially entirely from fibers consisting essentially of the high tenacity materials. In addition, woven fabrics made from such materials have typically been woven from yarns comprising fibers in the form of continuous filaments formed of the high tenacity materials. An exemplary list of high tenacity fibers useful in the context of the present invention includes, but is not limited to, fibers formed of para-aramids (e.g., KEVLAR™, TWARON™, and TECHNORA™), liquid crystal polyesters (e.g., VECTRAN™), ultra high molecular weight polyethylenes (e.g., SPECTRA™), and poly (p-phenylene-2,6-benzobisoxazole)(PBO) (e.g., ZYLON™).
[0036] “Non-high tenacity fibers” as used herein are natural or synthetic fibers having a tensile breaking strength of less than about 10 g/Denier, preferably less than about 8 g/Denier, in some embodiments less than about 5 g/Denier, and in yet other embodiments less than about 3 g/Denier. Potentially useful non-high tenacity fibers within the context of the present invention include, but are not limited to, fibers formed of materials such as polyamides (e.g., nylon), cellulosic materials (e.g., cotton), polyesters, acrylic polymers, and polyolefins. An exemplary, but non-limiting, list of articles of apparel and rugged outerwear that can be advantageously constructed from the intimate blend fabric layers provided according to the invention include, for example, gloves, aprons, chaps, pants, boots, gators, shirts, jackets, coats, socks, shoes, undergarments, vests, waders, hats, gauntlets, etc.
[0037] As mentioned above, one important purpose for including high tenacity fibers in some intimate blend fabrics according to the invention is to increase the puncture, cut, and/or tear resistance of materials used for rugged outerwear/sportswear, when compared to fabrics made of the non-high tenacity materials typically employed in the prior art. Accordingly, while, in some embodiments, the intimate blends can comprise non-woven fabrics, for example, knitted or felted fabrics (felts), in preferred embodiments the intimate blend fabric layers comprise a woven fabric, and in some preferred embodiments comprise a tightly woven fabric having a high cover factor. In preferred embodiments, an intimate blend woven layer provided according to the invention has a fill yarn cover factor (explained below) of at least about 75% of full and a warp yarn cover factor of at least about 100% of full, or a round packed (explained below) fill yarn cover factor of at least about 65% of full and a round packed warp cover factor of at least about 35% of full. A detailed description of the fabric geometry, calculation of various cover factors, and methods of construction of densely woven fabrics having high cover factors, as discussed herein, can be found in commonly owned U.S. Pat. Nos. 5,565,264 and 5,837,623, commonly owned International Patent Application Serial No. PCT/US00/28796 having an International Publication Number of WO 01/29299, co-pending U.S. patent application Ser. No. 09/691,491, and U.S. Provisional Application Serial No. 60/229,708, each incorporated herein by reference.
[0038] Any of the below described inventive fabric layers, including intimate blend fabric layers, can be used as single layers, be stacked and/or bonded into multiple layer structures, and/or can be layered/laminated with other fabric or non-fabric layers, for example a water impermeable, breathable membrane barrier layer, as discussed in more detail below. The inventive fabrics can also be coated with a variety of high or low modulus polymeric coatings to increase puncture, cut, and/or tear resistance. Such coatings and techniques for their application are described in detail in the above-mentioned commonly owned U.S. Pat. Nos. 5,565,264 and 5,837,623, commonly owned International Patent Application Serial No. PCT/US00/28796 having an International Publication Number of WO 01/29299, and co-pending U.S. patent application Ser. No. 09/691,491.
[0039] A wide variety of well known weaving processes and equipment can potentially be utilized for forming the high cover factor, tightly woven fabrics, including the intimate blend fabrics, preferred according to some embodiments of the invention. Because the preferred fabrics are tightly or densely woven as described above and in more detail below, in order to improve weavability and decrease yarn breakage, in preferred embodiments, wherein yarns comprising spun or otherwise bundled staple fibers are utilized for forming the intimate blend fabrics according to the invention, it is preferred that the yarns be formed from more than one fiber bundle plied together with a relatively high level of secondary twist, as described below, and/or that the yarns be formed from single fiber bundles having a relatively high primary twist level, as also described below. In addition, the weavability of the yarns and fiber bundles disclosed herein (and/or the spinnability of the staple fibers to form fiber bundles/yarns) can, in some cases, be improved by one or more of the following: increasing the length of the individual staple fibers; decreasing the size per unit length (Denier) of individual staple fibers used for spinning fiber bundles/yarns; forming intimate blend fiber bundles/yarns including staple fibers (e.g., cotton, or micro denier nylon or polyester staple fibers) which can improve the spinnability and integrity of the spun fiber bundles/yarns; and/or through use of any of a variety of well-known polymeric or non-polymeric sizing agents to stabilize and increase the mechanical integrity of the fiber bundles/yarns.
[0040] In general, the terms “tightly woven” or “high cover” or “high cover factor” as used herein to describe certain preferred embodiments of woven fabric layers refers to a fabric layer having a cover factor of at least about 75% of full in the fill (as measured between two warp ends) and a cover factor of at least about 100% in the warp (as measured at the center of the fill yarn where there can be effective overlap of the warp yarns on opposite sides of the fill yarn, thus leading to warp cover at the fill crossing potentially greater than 100% of full ). “Cover factor” or “cover” as used herein, (except when modified by the prefix “round packed,” see below) refers to the fraction, expressed as a percentage, of the total area of a fabric occupied by fibers as measured in the woven fabric. The above-mentioned cover factor is expressed as a percent of full coverage (i.e., 100% of the total area) occupied by yarns such as would occur if the yarns were laid out in a single layer, side by side, and in contact with each other). “Cover factor” as used herein can be calculated, for a unit length of fabric, as the sum of each of the measured widths of the yarns (see sentence below for a description of appropriate yarn width for warp and fill) in a given cross-section, divided by the total width of the fabric cross-section (see also U.S. Pat. No. 5,565,264). When calculating the cover factor in the warp, the appropriate yarn width utilized is simply the width of each warp yarn as measured at the fill crossing; however, when calculating the cover factor in the fill by this method, because there is a warp yarn positioned between each of the fill yarns due to the crimp in the woven structure, the effective yarn width which is used in the calculation is equal to the sum of the widths of a fill yarn and a warp yarn, as measured between the fill crossings
[0041] In some preferred embodiments, the high cover fabrics, including high cover intimate blend fabrics, are densely woven to have a fill yarn cover factor of at least about 80%, in other embodiments at least about 85%, and in yet other embodiments at least about 88%. In certain preferred embodiments, the high cover fabrics, including high cover intimate blend fabrics, are densely woven to have a warp yarn cover factor of at least about 110%, in other embodiments at least about 120%, in other embodiments at least about 130%, in other embodiments at least about 140%, in other embodiments at least about 145%, and in yet other embodiments at least about 150%.
[0042] An alternative way of calculating and expressing the weave density of the woven fabrics used herein is by determining the degree of surface area occupied based on the “round packed cover factor.” The “round packed cover factor” as used herein refers to a measure of cover calculated as discussed immediately below. The round packed cover factor is calculated essentially as described in the above paragraphs, except instead of using the actual measured yarn widths in the woven fabrics in the calculation, the width of a hypothetical round cross-section monofilament yarn of the same overall weight per unit length (Denier) is used. To determine the appropriate yarn diameter, the weight per unit length of the actual yarn is divided by the density or specific gravity of the material forming the yarn fibers (or an appropriate average density/specific gravity for a yarn comprising more than one fiber type) and the diameter is then calculated from the resulting cross-sectional area by assuming the yarn is a single filament with a round cross-section. The “round packed cover factor” is then determined as number of yarns in a cross-section of a given length of fabric multiplied by the width/diameter per yarn, as calculated above, divided by the length of the cross-section. This calculation is done for both the warp and fill directions. As above, the appropriate fill yarn width/diameter for this calculation should be based upon the sum of the width/diameter of a warp yarn plus a fill yarn. Note that the maximum theoretical round packed cover factor as calculated above would be 100% of full (i.e. when the number of yarns per unit length is high enough that the hypothetical yarns (i.e. with a diameter based on the round shape/monofilament assumption) when laid out side-by-side in a single layer would be in contact with their neighbors. A “high cover factor” fabric as the term is used herein can also be characterized by a round packed cover factor of at least about 65% of full for the fill yarns and at least about 35% of full for the warp yarns.
[0043] In some preferred embodiments, the high cover fabrics, including high cover intimate blend fabrics, are densely woven to have a round packed fill yarn cover factor of at least about 70%, in other embodiments at least about 80%, in other embodiments at least about 90%, and in yet other embodiments at least about 95%. In certain preferred embodiments, the high cover fabrics, including high cover intimate blend fabrics, are densely woven to have a warp yarn round packed cover factor of at least about 40%, in other embodiments at least about 50%, in other embodiments at least about 60%, and in yet other embodiments at least about 70%.
[0044] Referring now to
[0045] As discussed above, there are many permutations for providing an intimate blend woven fabric according to one aspect of the invention. For example, in one embodiment, the fiber bundles comprising warp yarns
[0046] In some embodiments, and preferably, at least one of the yarns includes at least one fiber bundle comprising fibers of at least a first fiber type and a second fiber type (and, if desired, a third, fourth, fifth, etc. fiber type). Such intimate blend fiber bundles and yarns can be interspersed with other intimate blend yarns of the same or different fiber composition and/or with yarns consisting essentially of fibers of a single fiber type, depending on the desired material properties of the overall fabric. In some preferred embodiments, each of the yarns forming the intimate blend fabrics is itself comprised of one or more fiber bundles, each of which can be an intimate blend of at least two different fiber types.
[0047] As one example, fabric
[0048] For intimate blend fabrics, such as
[0049] Essentially, any of the well known methods for spinning cut and/or stretch-broken staple fibers can potentially be utilized for producing spun yarns/fiber bundles, including intimate blend yarns/fiber bundles, according to the invention. For example, for staple fibers having a staple length of between about 1 inch and about 2 inches, the well known Cotton System spinning techniques can be utilized to form twisted yarns comprising a single fiber bundle and/or plied yarns comprising two or more twisted fiber bundles. For staple fibers between about 2 inches and about 4 inches, the well known Worsted System spinning techniques can be utilized for forming the spun yarns/fiber bundles according to the invention. In addition, stretch broken staple fibers having very long staple lengths, e.g., about 20-40 inches, can also be used to form intimate blend yarns; however, the use of such long staple fibers is generally less preferred than the use of shorter staple fibers as in the above-mentioned Cotton and Worsted spinning systems when forming intimate blend fiber bundles. When using long stretch-broken staple fibers for forming intimate blend yarns, it is preferred that each fiber bundle consist essentially of essentially a single fiber type, with the intimate blend yarn formed of two or more such fiber bundles plied together to form a plied yarn (e.g., as illustrated in
[0050] It is generally desirable when constructing articles of apparel for use as rugged outerwear that the woven fabrics utilized be formed of yarns having a relatively small weight per unit length and overall cross-sectional diameter, in order to enable the fabrics to be constructed with a desirably low weight per unit coverage surface area, a desirable degree of flexibility and softness, etc. However, typical prior art high tenacity fibers, either in continuous filament form or staple fiber form, cannot typically be successfully spun or formed into fiber bundles having a weight per unit length of less than about 100 Denier (for continuous filament yarns) or a length per unit weight of greater than about 50 Cotton Count (for yarns consisting essentially of spun high tenacity staple fibers). With respect to yarns formed of only high tenacity staple fibers spun using Cotton System spinning, a reason why yarns having a length per unit weight of greater than about 50 Cotton Count, or equivalently a weight per unit length of less than about 106 Denier, are not generally preferred for weaving fabric, especially high cover factor woven fabric, according to the invention, is that typical minimum Denier per fiber/filament of commercially available high tenacity fibers is relatively high, ranging typically form about 0.5 Denier per fiber to about 5 Denier per fiber. Accordingly, small diameter, light yarns that consist entirely of short staple lengths of such high tenacity fibers will typically have too few individual fibers present in a cross section of the yarn to enable the yarn to be successfully woven, especially densely woven into a high cover factor fabric, without failure of breakage of the yarn. Accordingly, it is advantageous, according to the invention, to form intimate blend fiber bundles from spun staple yarns that include fibers of high tenacity materials, as described above, in combination with staple fibers of other materials, for example, cotton, or low tenacity synthetic materials, which are available in fiber weights having a Denier per filament substantially below that typically available for high tenacity fibers. For example, in some preferred embodiments, high tenacity staple fibers are intimately blended with more spinnable fibers, for example micro denier polyester or nylon staple fibers or cotton, having a small Denier per filament and providing a higher level of interfiber shear than typical high tenacity-material fibers. By forming yarns/fiber bundles from high tenacity fibers in combination with such small, high interfiber shear-creating low tenacity fibers, the number of filaments in an intimate blend yarn/fiber bundle cross-section can be increased for a given yarn/fiber bundle weight and diameter, which, in turn, can lead to the ability to spin finer yarns/fiber bundles, especially when utilizing Cotton System spinning, and improve fabric weight, hand, softness, and overall performance.
[0051] In view of the above, to provide a tightly packed, mechanically stable yarn, for embodiments including one or more yarns comprising an intimate blend fiber bundle, and especially yarns comprising a single intimate blend fiber bundle, it is preferred that the yarn be characterized by a primary twist multiplier of at least about 2.7, in other embodiments of at least about 3, in other embodiments of at least about 4, in other embodiments of at least about 4.5, and in yet other embodiments of at least about 5. In some embodiments, for example those embodiments including yarns comprising an intimate blend fiber bundle having a fiber of a first type comprising a high tenacity material and a fiber of the second type comprising a low tenacity, non-high tenacity material, as discussed above, preferably, the fiber of the second type has a weight per unit length less than the fiber of the first type. Preferably, when forming intimate blend fiber bundles from spun staple fibers, as discussed above, the weight per unit length of the non-high tenacity fiber will be less than that of the high tenacity fiber. Also preferably, in some such embodiments, the weight per unit length of the high tenacity fiber does not exceed about 5 Denier per fiber, more preferably does not exceed about 2.5 Denier per fiber, even more preferably does not exceed about 1.5 Denier per fiber, in other embodiments does not exceed about 1 Denier per fiber, and in yet other embodiments does not exceed about 0.5 Denier per fiber. Also preferably, in some such embodiments, the non-high tenacity fiber intimately blended with the high tenacity fiber in the intimate blend fiber bundle has a weight per unit length that does not exceed about 1.2 Denier per fiber, more preferably does not exceed about 0.8 Denier per fiber, more preferably does not exceed about 0.5 Denier per fiber, more preferably does not exceed about 0.25 Denier per fiber, and more preferably does not exceed about 0.1 Denier per fiber.
[0052] In preferred embodiments, as discussed above, relatively small diameter, lightweight fiber bundles/yarns are desirable for forming the fabrics according to the invention. In some preferred embodiments, wherein the fabric includes one or more yarns formed of an intimate blend fiber bundle, such fiber bundle includes within any given cross-section of the fiber bundle along its length between about 60 and about 100 fibers. In preferred embodiments, the intimate blend fiber bundles formed of a plurality of spun staple fibers and used for forming at least some yarns of certain inventive fabrics have a length per unit weight exceeding about 50 Cotton Count and a weight per unit length less than about 106 Denier, in other preferred embodiments have a length per unit weight exceeding about 60 Cotton Count and a weight per unit length less than about 89 Denier, in other preferred embodiments have a length per unit weight exceeding about 70 Cotton Count and a weight per unit length less than about 76 Denier, in other preferred embodiments have a length per unit weight exceeding about 80 Cotton Count and a weight per unit length less than about 66 Denier, and in yet other preferred embodiments have a length per unit weight exceeding about 85 Cotton Count and a weight per unit length less than about 63 Denier.
[0053] Referring now to
[0054] Referring now to
[0055] For example, as illustrated in the cross-sectional view of
[0056] High Cover Factor/Small Fill Yarn Fabrics
[0057] The present invention also provides woven fabric constructions for high cover factor woven fabrics yielding more lightweight and flexible fabrics than those typically available utilizing prior art woven constructions. Such constructions, as disclosed below, are particularly useful for forming woven fabrics from yarns consisting essentially of high tenacity fibers or filaments; however, such constructions can also be beneficial in the context of intimate blend fabrics, such as those discussed above, or high cover factor, densely woven fabrics consisting essentially of non-high tenacity fibers.
[0058] High cover factor woven fabrics formed from high tenacity para-aramid fibers and filaments are known from commonly owned U.S. Pat. Nos. 5,837,623 and 5,565,264. However, as described below, prior art constructions of high cover factor fabrics, and especially those formed of high tenacity fibers or filaments, are typically characterized by warp yarns that are smaller in size than the fill yarns of the fabrics (i.e., the weight per unit length of the warp yarns is less than the weight per unit length of the fill yarns or, equivalently, the length per unit weight of the warp yarns is greater than the length per unit weight of the fill yarns).
[0059]
[0060]
[0061]
[0062] In some preferred embodiments of the inventive fabrics having fill yarns with a weight per unit length less than the weight per unit length of warp yarns of the fabric, the fabric has a fill yarns cover factor of at least about 80%, in other embodiments at least about 85%, and in other embodiments at least about 88%. In some preferred embodiments, the fabric can have a warp yarn cover factor of at least about 110%, in other embodiments at least about 120%, in other embodiments at least about 130%, in other embodiments at least about 140%, in other embodiments at least about 145%, and in yet other embodiments at least about 150%.
[0063] In some preferred embodiments, the weight per unit length of fill yarns
[0064] In preferred embodiments, at least one yarn of fabric
[0065] The above-described high cover factor, small fill yarn constructions can be formed via any of a wide variety of known weaving methods using essentially conventional fabric weaving equipment known to those of ordinary skill in the art. The primary modification to standard weaving techniques for forming puncture-resistant fabrics having conventional constructions (i.e., having a fill yarn weight per unit length exceeding the warp yarn weight per unit length) being that the inventive high cover factor, small fill yarn constructions require a greater number of warp yarn insertions per unit length of fabric in the machine direction and, accordingly, a longer time required to weave a given length of fabric. However, any potential loss of value due to increases in weaving time required to form the high cover factor, small fill fabrics provided according to the invention can be more than offset by the improved properties of the woven fabrics having the inventive construction, when compared to those prepared according to prior art constructions (especially for fabrics woven from yarns consisting essentially of high tenacity fibers). For example, for a given level of fill cover factor and warp cover factor and for a similar level of puncture, cut, and tear resistance, a high cover factor, small fill yarn fabric produced according to the invention utilizing yarns consisting essentially of para-aramid high tenacity fibers can have a weight reduction per unit area of up to about 60% or more, a reduction in fabric stiffness of up to about 75% or more, and a reduction in fabric thickness of up to about 50% or more, when compared to conventional constructions, for example as illustrated in
[0066] Another advantage of the inventive construction for providing high cover factor woven fabrics, in which the weight per unit length of the fill yarn is less than the weight per unit length of the warp yarn, is that such fabrics typically can have more balanced tensile properties, in comparison to more conventional designs in which the fill yarns have a weight per unit length equal to or exceeding the weight per unit length of the warp yarns. The greater degree of balance in tensile properties of the high cover, small fill fabrics is a result of the warp yarns having, in general, a lower degree of crimp (i.e., excess length in comparison to the overall length of the fabric in the machine direction), when compared to conventional designs wherein the warp yarns are woven around relatively larger diameter fill yarns (i.e., equal to or larger in size than the diameter of the warp yarns for systems in which the warp yarns and fill yarns are formed of materials having a similar density or specific gravity). For the small fill yarn constructions provided according to the invention, in addition to having, in general, a lower degree of warp crimp owing to the relatively smaller diameter of the fill yarns, because the smaller fill yarns, in many cases, are more flexible than in conventional designs (i.e., because, typically, they can be smaller in diameter) some of the warp crimp will be distributed to the fill yarns after weaving. Accordingly, constructions provided according to the present aspect of the invention can provide woven fabrics in which the degree of crimp is more evenly matched between the warp yarns and the fill yarns, thus leading to the above-mentioned more balanced tensile properties in each of the warp and fill directions. In general, the more highly crimped the yarn is in the woven fabric, the lower will be the ratio of actual tensile breaking strength per cross-sectional area of the yarn to the theoretical maximum tensile breaking strength per cross-sectional area of the fibers forming the yarn. Accordingly, the inventive high cover factor, small fill construction can, in many embodiments, result in a conversion efficiency of the tensile strength of the fibers forming in the fabric (i.e., the ratio of the actual tensile breaking strength of the fabric along a given direction to the theoretical maximum tensile strength of the fibers) substantially higher than typically achievable for the above-described conventional constructions.
[0067] As discussed above with regard to intimate blend fabrics, typically, high tenacity yarns consisting essentially of high tenacity fibers, such as para-aramids, are characterized by a relatively large denier per filament/fiber and a relatively low degree of inter-fiber shear, thus making formation of yarns having small weights per unit length difficult when utilizing conventional high tenacity yarn forming techniques. In some embodiments, the small fill, high cover factor fabrics provided according to the invention are be formed from yarns consisting essentially of continuous filament high tenacity fibers. Theoretically, since the mechanical integrity of such yarns is not strongly dependent on the number of individual fibers per yarn or the inter-fiber shear, such continuous filament yarns could be utilized to weave fabrics having yarns, for example small fill yarns, having a weight per unit length of, for example, 30 Denier or less. However, currently continuos filament high tenacity yarns having a weight per unit length of less than about 100 Denier are not readily available in commercial quantities.
[0068] Alternatively, yarns comprising or consisting essentially of high tenacity fibers can be formed from staple fibers via spinning. In one such embodiment, a well-known Cotton System spinning technique, which comprises necking down a carded web of staple fibers each having a length of between about 1 inch and about 2 inches, can be utilized. For embodiments involving yarns formed from a single fiber bundle consisting essentially of high tenacity staple fibers spun utilizing a Cotton System spinning technique, it is preferred that such yarn, when used as a fill yarn, have a length per unit weight of at least about 50 cotton count and, when used as warp yarns have a length per unit weight of at least about 50 cotton count and furthermore be plied with at least one other like fiber bundle to form a two-ply warp yarn. Alternatively, a Worsted Spinning system technique utilizing staple fibers having a length of between about 2 inches and about 4 inches can be utilized to produce high tenacity yarns having a length per unit weight greater than the above-mentioned values for the Cotton Spinning system spun yarns, since with the Worsted Spinning system techniques, the increased length of the staple fibers improves the stability and strength of the lighter yarns. As discussed above in the context of intimate blend yarns and fabrics, for embodiments involving yarns formed from spun staple fibers, it is preferred that the fiber bundles have a relatively high degree of primary twist to improve their stability, and, for embodiments where the yarns comprise two or more fiber bundles plied together, that the plied yarns be characterized by a relatively high level of secondary twist. For example, in preferred embodiments, fiber bundles formed of spun staple fibers are characterized by a primary twist multiplier of at least about 2.7, in other embodiments at least about 3, in other embodiments at least about 3.5, in other embodiments at least about 4, and in yet other embodiments at least about 5. For embodiments involving yarns comprising two or more plied fiber bundles, it is preferred that such yarns have a secondary ply twist of at least about ¼ that of the level of primary twist of the fiber bundles, in other embodiments of at least about ½ that of the level of primary twist of the fiber bundles, and in other embodiments of at least about the same as the level of primary twist of the fiber bundles. Such high twist, while being preferred and useful for yarns formed from either or both of high tenacity and non-high tenacity fibers, are especially preferred for embodiments involving yarns and fiber bundles consisting essentially of spun high tenacity staple fibers. In addition to, or in place of the relatively high twist multipliers mentioned above, the spun fiber bundles and/or yarns can be stabilized via use of one or more adhesive sizing agents, for example an adhesive sizing agent comprising a water soluble coating, such as, one or more of those selected from the list including, but not limited to, polyvinyl alcohol (PVA), polyacrylic acid (PAA), and starch.
[0069] For embodiments of high cover factor, small fill woven fabrics comprising high tenacity fibers and including fill yarns having a weight per unit length of less than about 100 Denier and/or warp yarns having a weight per unit length less than about 200 Denier, it is preferred that the yarns be formed from stretch broken fibers having a relatively long staple length (e.g., 20 inches-40 inches), continuous filament fibers, or be formed of one or more fiber bundles comprising an intimate blend of the high tenacity fibers in combination with finer, more spinnable, natural and/or low tenacity synthetic fibers (preferably with at least 5% of the total fibers of the intimate blend fiber bundle being high tenacity fibers, especially for intimate blend fiber bundles comprising the small yarns), thereby providing a relatively high level of interfiber shear (such fibers and yarns being described in detail above with regard to intimate blend fabrics).
[0070] Layered/Laminated Fabric Systems
[0071] Another aspect of the present invention involves provision of various multi-layer fabric systems including therein a puncture-resistant layer in combination with one or more additional layers providing one or more desirable features or attributes of a fabric for use as an article of apparel, especially sporting apparel or apparel for use as rugged outerwear. As described in more detail below, the puncture-resistant layer can, in preferred embodiments, comprise a fabric, for example either a woven fabric or a non-woven fabric (such as a knitted or felted fabric (felt)). In some preferred embodiments, the puncture-resistant layer can comprise a woven fabric that is a high cover factor fabric, as previously defined, and/or that comprises or consists essentially of high tenacity fibers. In some embodiments, the puncture-resistant layer can comprise one or more layers of an intimate blend fabric, as described above, and/or a high cover factor, small fill yarn fabric, also as described above. In other embodiments, the puncture-resistant layer can comprise one or more layers of a conventional woven fabric consisting essentially of high tenacity fibers, for example as illustrated previously in
[0072] Referring now to
[0073] In some preferred embodiments, breathable barrier layer
[0074] In some embodiments, microporous or monolithic membrane layer
[0075] In alternative embodiments, as mentioned above, microporous or monolithic membrane layer
[0076] As mentioned above, puncture-resistant layer
[0077] Because, typically, microporous or monolithic membrane layer
[0078] Referring now to
[0079] As discussed above in the context of
[0080] Referring now to
[0081]
[0082] As mentioned above, in preferred embodiments, liner/shell layer
[0083] As mentioned previously, in some embodiments, puncture-resistant layer
[0084] Referring now to
[0085] In some preferred embodiments, layer
[0086] Dyeability/Printability of Fabrics Comprising High Tenacity Fibers and Pre-Washing of Fabrics Comprising High Tenacity Fibers to Increase Puncture Resistance and Flexibility
[0087] Dyeability and printability are important attributes of fabrics for use in rugged outerwear applications. In order to be appealing to consumers of rugged outerwear apparel products, the quality, consistency, and variety of colors available must be high. In addition, printed and/or dyed patterns, such as camouflage patterns, are especially useful and desirable for rugged outerwear applications. As discussed above in the context of intimate blend fabrics, fabrics constructed of natural fibers, for example, cotton, and/or many synthetic, non-high tenacity fibers, for example, polyamides, polyesters, acrylic polymers, polyolefins, typically utilized in constructing conventional rugged outerwear, often have excellent dyeability and/or printability characteristics. In contrast, typical prior art fabrics constructed from high tenacity fibers, such as the high tenacity fibers and materials discussed previously, are not readily dyeable and do not, typically, yield fabrics, upon dyeing, having an essentially visually uniform color density of the dyed color. Typically, in order to form fabric materials of a color different from the base color of the high tenacity fiber material forming the fabric, in prior art techniques, a dye or coloring agent was added directly to the high tenacity polymeric material itself prior to extrusion to form fibers or filaments, which fibers or filaments were subsequently formed into yarns and fabrics. However, such pre-fiber formation dyeing can be expensive, lacks flexibility, is not suitable for pattern dyeing or printing, and is typically only useful for colors that are darker than the base color of the high tenacity material forming the high tenacity fibers (e.g., para-aramid and liquid crystalline polyester have a base color of gold/yellow).
[0088] As mentioned above, the present invention provides a number of fabrics and fabric systems comprising high tenacity fibers, which have improved dyeability and printability characteristics over the above-mentioned prior art fabrics. For example, in the multi-layer/laminate systems described above, one or more layers of puncture-resistant fabrics comprising or consisting essentially of high tenacity fibers can be combined with one or more layers of fabrics comprising or consisting essentially of non-high tenacity fibers of a class that are highly dyeable and printable (e.g., cotton fibers, polyamide fibers, polyester fibers, polyacrylic fibers, polyolefin fibers, etc.).
[0089] In particular, the above-described intimate blends can provide both desirable levels of cut, tear, and puncture resistance, owing to their containing one or more types of high tenacity fibers in their structure, in addition to excellent dyeability and printability, owing to their also containing a plurality of highly printable and dyeable fibers, in preferred embodiments. Therefore, in one aspect, the present invention provides an intimate blend fiber bundle formed of a plurality of fibers, at least 5% of which are high tenacity fibers, where the fiber bundle also includes a plurality of dyeable fibers, for example, natural and/or synthetic non-high tenacity fibers of the types described previously, such that upon exposure of the fiber bundle to a fabric dye, the fiber bundle becomes dyed to an essentially visually uniform color density.
[0090] Essentially any of the above-mentioned high tenacity materials and fiber types for use in forming intimate blends can be utilized, together with more printable, dyeable fiber types, to yield such a dyeable fiber bundle. Such fiber bundles can be constructed and formed as described above in the context of the discussion of intimate blends and can be formed into single-ply and/or multi-ply yarns and woven into intimate blend fabrics, also as described previously. Any of a wide variety of well known fabric dyes able to dye the dyeable, non-high tenacity fibers of the intimate blend can be utilized for dyeing the intimate blend fiber bundles and fabrics, including, for example, cationic dyes, anionic dyes, and polyester dyes. Significantly, because many natural and synthetic materials for forming the dyeable, non-high tenacity fibers utilized in the intimate blends can have a base color significantly lighter than the base color of the high tenacity fibers, it is possible to dye the intimate blend fiber bundles, yarns, and fabrics to have a visually uniform color density that is lighter in color than the undyed color of the high tenacity fibers within the intimate blend. As mentioned above, for such dyeable intimate blends, it is preferred that at least about 5% of the fibers forming an intimate blend fiber bundle be high tenacity fibers, in other embodiments, at least 10% of the fibers are high tenacity fibers, in other embodiments at least 20%, in other embodiments at least 50%, in other embodiments at least 65%, in other embodiments at least 75% and in yet other embodiments at least 85% of the fibers are high tenacity fibers.
[0091] The pre-washing of roll stock of a fabric before forming the fabric into an article of apparel is well known and widely practiced in the art for materials formed of natural fibers, for example in denim processing. Previously, however, such pre-wash methods have been typically limited to use in cotton or cotton-blend material applications. It has been found, within the context of the present invention, that such pre-wash methods can have a strong effect on the flexibility and/or puncture resistance of fabrics comprising or consisting essentially of high tenacity fibers, for example, of the types discussed previously. Accordingly, in one aspect, the invention provides a method of pre-washing roll stock of a fabric that includes at least one high tenacity fiber to increase the puncture resistance of the fabric. Such a pre-wash method can also be employed for essentially any of the above-mentioned high cover factor puncture-resistant fabrics discussed previously to increase puncture resistance and/or flexibility including, for example, intimate blend fabrics and high tenacity fabrics consisting essentially of high tenacity fibers.
[0092] A variety of well known pre-wash techniques utilized for cotton or cotton-blend material can potentially be utilized in the context of the present invention to perform the inventive pre-wash method of increasing the puncture resistance and/or flexibility of fabrics comprising high tenacity fibers. In general, such a pre-washing method will comprise a step of saturating the fabric with an aqueous solution of a surfactant, followed by subjecting the fabric to mechanical flexing and agitation. The duration of the pre-wash will, as will be apparent to those of ordinary skill in the art, depend on the mechanical intensity of the flexing and agitation imparted by the particular washing equipment employed. In one embodiment, wherein the mechanical flexing and agitation is performed within a commercial drum washing machine, a typical duration of the mechanical flexing and agitation step of the pre-wash method would range from about 1 hour to about 5 hours. Optimal conditions and agitation times for increasing the puncture resistance and flexibility of fabrics comprising high tenacity fibers will, as will be apparent to those of ordinary skill in the art, depend upon the particular materials and construction of the fabrics undergoing the pre-wash treatment. The determination of selection of such parameters is best determined for a given fabric via routine experimentation and optimization involving the adjustment of parameters and exposure times followed by subsequent testing of the pre-washed materials for puncture resistance and bending stiffness (utilizing well-known ASTM testing methods). Conditions which yield a desirable and/or maximal increases in the above properties in comparison to the material prior to the pre-wash would constitute preferred operating conditions for performing the pre-wash method for a given fabric.
[0093] As one example, for an embodiment of an intimate blend fabric woven of cotton warp yarns and fill yarns formed of an intimate blend of cotton, polyester, and para-aramid fibers, the fabric is preferably washed at a full boil with a detergent/surfactant with the pH adjusted to 9-10. This wash liquor and conditions are preferably selected to de-size the fabric (i.e. remove or reduce the quantity of any sizing agents present in the fabric). The material can be run open width or as a rope if the process is open with the tension adjusted to be low. The material can then be rinsed with boiling water and dried open width on steam drums or with many other known textile drying systems. The drying process preferably is performed under a low tension to allow for maximum shrinkage. The wash process time can be selected and adjusted by trial and error to determine the point were the material reaches the desired level of improvement of puncture resistance and flexibility. Under such preferred conditions, the pre-washing step can increase the puncture resistance of a fabric comprising high tenacity fibers by at least about 5%, in other embodiments by at least about 10%, in other embodiments by at least about 15%, in other embodiments by at least about 20%, and in yet other embodiments by at least about 25%, while decreasing the bending stifftess of the fabric by at least about 5%, in other embodiments by at least about 10%, in other embodiments by at least about 15%, in other embodiments by at least about 20%, and in yet other embodiments by at least about 25%.
[0094] The function and advantage of these and other embodiments of the present invention will be more fully understood from the examples below. The following examples are intended to illustrate the benefits of the present invention, but do not exemplify the full scope of the invention.
[0095] Intimate Blend Fiber Bundle Fabrics
[0096] The table below summarizes the characteristics and relative performance of six tightly woven intimate blend fabrics. The fabrics were each woven with essentially the same construction utilizing yarns formed from single fiber bundles spun using a Cotton System spinning method. The fiber bundles forming the yarns for each of the illustrated fabrics had the same fiber count as measured in the cross section of the bundle. The fiber bundles were intimate blends of a first, high tenacity fiber type (Fiber TABLE 1 Light Denier Cotton System Yarn with Constant Fiber Count in Cross Section Fiber 1 Fiber 2 Blend Staple Spinning Size Puncture Abrasion Cut Para Nylon 50/50 1.5-2″ Cotton 57/1 cc Good Good Good Aramid 1.2 dpf System (90d) 1.5 dpf Para Poly- 50/50 1.5-2″ Cotton 72/1 cc Good Fair Good Aramid ester System (70d) 1.5 dpf 0.8 dpf Para Poly- 75/25 1.5-2 Cotton 61/1 cc Very Poor Very Aramid ester System (94d) good good 1.2 dpf 0.8 dpf Para Poly- 25/75 1.5″2″ Cotton 83/1 cc Fair Fair Fair Aramid ester System (62d) 1.5 dpf 0.8 dpf Para Combed 50/50 1.5-2″ Cotton 57/1 cc Good Good Good Aramid Cotton System (90d) 1.5 dpf long staple Para Combed 20/80 1.5-2″ Cotton 50/1 cc Good Fair Fair Aramid Cotton System (105d) 1.5 dpf long staple Liquid Poly- 50/50 1.5-2″ Cotton 50/1 cc Very Very Very Crystal ester System (105d) good good good Poly- 0.8 dpf ester 5 dpf
[0097] Para-aramid/Polyester/Cotton Intimate Blend Fabric
[0098] The fabric of the present example was designed to be well suited for general sports wear applications. In particular the fabric has excellent resistance to puncture by thorns and other sharp objects. The use of the fabric in conjunction with a breathable barrier membrane, in a multi-layer system, is very effective as the cut and puncture resistance of this material protects the membrane from damage.
[0099] This fabric can protect against snakebite and has a needle puncture resistance (measured by the penetration test described in detail in commonly owned U.S. Provisional Patent Application Serial No. 60/229,708) greater than 2 lbs. for a multi-layer fabric with two layers of the fabric of the present example.
[0100] This fabric is very soft and has good aesthetics in use. The design can allow for cost effective dying and the combination of cotton with the para aramid gives a very aesthetic surface to the fabric. In many applications the use of durable water repellent layer(s) in combination with the intimate blend fabric is advantageous.
[0101] The fiber bundles comprising the yarns of the fabric were formed from combed ring spun long staple fibers. The overall intimate blend fabric construction design was roughly 15% para aramid by weight.
[0102] Detailed Design of the Fabric:
[0103] Warp: 110 warp yarns per inch. Warp yarns were formed of cotton staple fibers with a two-ply construction, each fiber bundle of the plied yarn having a length per unit weight of approximately 60 Cotton Count (i.e. a 60/2 construction).
[0104] Fill: 70-80 fill yarns per inch. Each yarn comprising a fill pick was an intimate blend 3-ply construction of the above-mentioned 60/2 cotton plied fiber bundles twisted together with a 70/1 (i.e. single fiber bundle of approximately 70 Cotton Count) intimate blend fiber bundle formed of microdenier polyester and para aramid fibers in a 20%/80% (polyester/para aramid) blend.
[0105] Round Packed Cover Factors: 60-65% in the warp; 85-95% in the fill.
[0106] Comparison of High Cover Factor, Small Fill Fabrics to Conventional High Cover Factor Fabric Constructions
[0107] Each of the woven fabrics in examples 9-11 below listed in Table 2 was prepared from yarns consisting of liquid crystalline polyester (VECTRAN™) high tenacity fibers and woven to provide essentially the same warp and fill cover factors. Each of the below constructions could also be made from intimate blend yarns and/or non-high tenacity fiber-based yarns if desired. Examples 12 and 13 are prophetic. Example 9 fabric was constructed to have a conventional construction with a ratio of fill yarn size to warp yarn size of 2/1. Example 10 fabric was constructed to have a conventional construction with a ratio of fill yarn size to warp yarn size of 1/1. Example 11 fabric was constructed with a small fill construction according to the invention, with a ratio of fill yarn size to warp yarn size of ½. Examples 12 and 13 are similarly constructed with a small fill construction according to the invention, with a ratio of fill yarn size to warp yarn size of ½. As can be seen, each of the small fill designs is significantly lighter than either of the conventional designs.
TABLE 2 High cover factor, high tenacity fabric constructions Warp Fill Count Count Fill Warp Ex- Warp Fill (yarns (yarns Cover Cover Weight am- Size Size per per Factor Factor (oz/ ple (Denier) (Denier) inch) inch) (%) (%) sq. yd) 9 200 400 110 65 85 140 7.2 10 200 200 110 77 85 140 5.75 11 200 100 110 90 85 140 4.75 12 150 75 130 110 85 140 4 13 100 50 160 135 85 140 3.2
[0108] High Tenacity Felts for Providing Cut Resistant Layers for Multi-layer and Laminate Fabric Systems
[0109] The following felted fabric layers are constructed from high tenacity fibers utilizing an air laid web manufacturing technique felts with random fiber positioning. The felts are consolidated as indicated and their cut performance is tested using the ASTM F-1790 test, and their puncture performance is tested using a standard needle puncture test utilizing an INSTRON™ force measurement machine with a 0.05 inch diameter hand sewing needle in conformance with ASTM D-1342.
TABLE 3 Felts for cut-resistant layers in multi-layer/laminate fabric systems Staple Length Bonding Cut Puncture Fiber type (inches) Entangling Adhesive Calendering Weight performance performance Para- 1.5 Needle None None 3-6 oz Good Good Aramid UHMW PE 1.5 Needle Low melt Yes 3-5 oz Good Fair sheath LC 1.5 Needle Soft Yes 3-6 oz Good Good Polyester urethanes
[0110] While several embodiments of the invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and structures for performing the functions and/or obtaining the results or advantages described herein, and each of such variations or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art would readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that actual parameters, dimensions, materials, and configurations will depend upon specific applications for which the teachings of the present invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described. The present invention is directed to each individual feature, system, material and/or method described herein. In addition, any combination of two or more such features, systems, materials and/or methods, provided that such features, systems, materials and/or methods are not mutually inconsistent, is included within the scope of the present invention. In the claims, all transitional phrases or phrases of inclusion, such as “comprising,” “including,” “carrying,” “having,” “containing,” “formed of,” “made of” and the like are to be understood to be open-ended, i.e. to mean “including but not limited to.” Only the transitional phrases or phrases of inclusion “consisting of” and “consisting essentially of” are to be interpreted as closed or semi-closed phrases.