Abstract:
A knitted textile fabric for use in safety apparel, comprising a first yarn containing modacrylic fibers and a second yarn containing cellulosic fibers. The first and second yarns are intimately interknitted with one another in plated relationship with the modacrylic yarn disposed predominantly at an outer face of the fabric for imparting flame resistant properties and an affinity for high visibility dyes and with the cellulosic yarn disposed predominantly at the opposite face of the fabric for imparting a hand suitable for comfortable body contact with a user&#39;s skin.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to textile fabrics suitable for use in safety apparel. More particularly, the present invention relates to such fabrics which are flame resistant and also have an affinity for high visibility dyes meeting established standards for such. 
         [0002]    Workers in many occupations are exposed to various personal safety hazards which can be mitigated by wearing safety apparel which provides selected properties such as flame resistance and high visibility. Such safety apparel has wide-spread applications across many varied occupations, such as in particular within the construction and manufacturing industries. 
         [0003]    To date, governmental organizations have not promulgated defined minimum standards for such safety apparel. However, private organizations, such as the American National Standards Institute (ANSI), the Safety Equipment Association (ISEA) and the American Society for Testing and Materials (ASTM), have published certain standards for safety apparel. For example, ANSI in conjunction with ISEA has established a standard for the minimum conspicuity of safety apparel used in certain occupational activities so as to be deemed “high visibility”, such standard commonly designated as ANSI/ISEA-107. ASTM has similarly developed a standard for minimum flame resistant in safety apparel, designated as standard ASTM F-1506. 
         [0004]    Until recently, the textile industry considered such standards to be essentially incompatible as the vast majority of textile fiber materials suitable for apparel fabrication which meet the ASTM F-1506 flame resistant standard are incapable of being dyed to a luminescence sufficient to meet the ANSI/ISEA-107 standard for high visibility and, visa-versa, the vast majority of textile fiber materials suitable for apparel fabrication which have a sufficient affinity for luminescent dyeing to meet the ANSI/ISEA-107 standard would not provide flame resistance properties meeting the ASTM F-1506 standard. 
         [0005]    However, it has been discovered that modacrylic fibers have a dye affinity and flame resistance characteristics capable of satisfying both standards and, accordingly, in recent years, textile fabrics have been developed which are composed entirely or predominantly of modacrylic fibers for use in fabricating safety apparel to meet each standard. Representative examples of such fabrics are disclosed in U.S. Pat. Nos. 6,706,650; 6,787,228; and 6,946,412, and U.S. Patent Application Publication No. 20040192134. 
         [0006]    While such modacrylic fabrics satisfy the aforementioned flame resistance and high visibility standards, safety apparel made from such fabrics has thus far achieved only limited acceptance within the apparel industry because such fabrics are stiff, abrasive and otherwise very uncomfortable when worn, particularly when in contact with a wearer&#39;s skin. Accordingly, there is a recognized and yet unmet need within the relevant safety apparel industry for an alternative fabric providing apparel-like hand and comfort properties while still meeting the relevant flame resistance and high visibility standards. 
       SUMMARY OF THE INVENTION 
       [0007]    It is accordingly an object of the present invention to provide a textile fabric which provides flame resistance and high visibility properties so as to be suitable for use in safety apparel but also provides a comfortable hand suitable for direct contact with a wearer&#39;s body. 
         [0008]    The present invention addresses this objective by forming a textile fabric of two different types of yarns integrated into the textile fabric such that one yarn having flame resistance and high visibility properties is disposed predominantly at one face of the fabric while the other yarn having a hand suitable for comfortable body contact with a user&#39;s skin is disposed predominantly at the opposite face of the fabric, whereby the fabric can be fashioned into safety apparel with the first-mentioned face disposed outwardly for flame resistance and high visibility protection and with the other face disposed inwardly towards the wearer&#39;s body to promote comfort by buffering the user&#39;s skin from the outer face of the fabric. 
         [0009]    While many varied embodiments of the fabric utilizing differing yarns and differing fabric constructions are contemplated to be possible, it is considered advantageous that the first yarn or yarns comprise a sufficient content of modacrylic fibers to provide the outer face of the fabric with the requisite flame resistance and affinity for high visibility dyeing so as to meet the currently established standards, ANSI/ISEA-107 and ASTM F-1506, and the other yarn should have a sufficient content of conventional apparel-suitable fibers, e.g., cellulosic, animal hair, silk, polyester, polyamide, acrylic, rayon, and polyimide fibers, so as to provide a comfortable hand to the inner face of the fabric. 
         [0010]    For example, but without limitation, it is contemplated that the first yarn appearing at the one outer face of the fabric may preferably have a content of modacrylic fibers ranging between twenty percent (20%) and one hundred percent (100%), while the second yarn appearing predominantly at the opposite inner face of the fabric may preferably have an apparel fiber content of at least about fifty percent (50%) and may also optionally include modacrylic fibers. In one particular embodiment of the present fabric, the one outer face yarn comprises approximately ninety percent (90%) modacrylic fibers and approximately ten percent (10%) polyester fibers, while the other inner face yarn comprises approximately fifty percent (50%) cotton fibers and approximately fifty percent (50%) modacrylic fibers. 
         [0011]    The fabric may be formed of any suitable construction by which the first yarns offering flame resistance and high visibility properties are disposed predominantly at the one outer face of the fabric and the second yarns offering comfort properties are disposed predominantly at the opposite inner face of the fabric. One particularly embodiment contemplated by the present invention is a knitted fabric wherein the two yarns are formed in plated relationship, e.g., by circular knitting presenting the first yarn at one fabric face and the second yarn at the opposite fabric face. While such a plated knit fabric construction is presently preferred, the present invention also contemplates various other textile fabric construction methodologies such as a plated warp knitted fabric construction, a so-called bi-ply knitted fabric construction, a so-called spacer-type warp knitted fabric construction, a two-ply woven fabric construction or an alternative woven fabric construction of a pattern presenting warp and weft yarns predominantly at opposite faces of the fabric, such as a twill fabric construction. 
         [0012]    Other features, characteristics and advantages of the present invention are described more fully hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  depicts diagrammatically in elevation the knitted structure of a textile fabric according to one preferred embodiment of the present invention; and 
           [0014]      FIG. 2  depicts diagrammatically in cross-section the knitted structure of the textile fabric of  FIG. 1 , as viewed along section line  2 - 2  thereof. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    Referring now to the accompanying drawings of  FIGS. 1 and 2 , a fragmentary portion of a textile fabric according to the present invention is shown at  10  in a representative embodiment fabricated by circular knitting on a circular knitting machine which may be of any suitable type the fabrication and construction of which is commonly known within the industry and therefore need not be fully described herein. 
         [0016]    Such knitting machines basically include a rotatable needle cylinder with axial needle slots formed at a spacing from one another about the outer circumferential surface of the cylinder. A plurality of knitting needles, typically latch-type needles each having a yarn receiving hook and a closeable latch assembly, are reciprocably disposed within the axial cylinder slots. Stationary needle-actuating cams are positioned outwardly about and adjacent to the needle cylinder. Typically, the knitting machine has multiple knitting stations at which yarn feeding fingers or other feeding instruments are positioned for yarn feeding disposition adjacent the upper end of the needle cylinder to feed yarn to the needles thereat. 
         [0017]    For the knitting of the fabric  10  according to the present invention, the knitting machine is set up at each knitting station to deliver simultaneously two yarns  12 ,  14 , described more fully hereinafter, to each needle via the yarn feeding instruments. As the needle cylinder rotates during operation, the needles are operatively manipulated within the respective slots of the cylinder by the adjacent stationary cams to receive and stitch the yarns  12 ,  14  into interknitted loops extending in circumferential courses and axial wales. The knitting of the fabric  10  proceeds in this fashion for a predetermined number of successive revolutions of the knitting machine sufficient to progressively knit the yarns  12 ,  14  into a continuous seamless length of tubular fabric  10  of a desired length. The simultaneous delivery of both yarns  12 ,  14  to each needle at each knitting station thusly forms the yarns in plated relationship in a single jersey stitch construction throughout the entirety of the fabric  10 . 
         [0018]    As will thus be understood, the resultant knitted structure of the fabric  10  is shown schematically in an enlarged form in the drawings of  FIGS. 1 and 2 . As indicated, each yarn  12 ,  14  is formed identically in plated needle loops  12   n ,  14   n  extending circumferentially about the fabric  10  in courses C and aligned lengthwise along the fabric  10  in perpendicular wales W. In the drawing of  FIG. 1 , the plated relationship of the yarns  12 ,  14  is depicted diagrammatically and schematically by showing the yarns side by side in the same plane, but those persons skilled in the art will recognize and understand that, within the three dimensional structure of the actual fabric  10 , the yarns  12 ,  14  are actually formed in overlying relationship with the yarn  12  disposed predominantly at one face of the fabric  10  while the yarn  14  is disposed predominantly at the opposite face of the fabric  10 , as shown in the cross-sectional view of  FIG. 2 . 
         [0019]    In accordance with the present invention, the yarns  12 ,  14  incorporated into the fabrication of the textile fabric  10  are selected to achieve differing physical and chemical properties in the fabric  10  at the opposite faces of the fabric. Specifically, the yarn  12  appearing at one face of the fabric is selected to have a sufficiently high content of a flame resistant material to impart to such face of the fabric flame resistance properties which will comply with prevailing flame resistance standards observed within the textile industry, particularly standard ASTM F-1506 established by the American Society for Testing and Materials. By contrast, the yarn  14  appearing at the opposite face of the fabric is a material of the type ordinarily utilized in apparel fabric to impart to such face of the fabric  10  a satisfactory hand, e.g., non-abrasive, flexible and not stiff, and essentially soft, to be suitable for direct body contact with the skin of a person wearing safety apparel. In this manner, the fabric  10  can be fabricated into safety garments with the face of the fabric predominantly comprised of the yarn  12  as outward face of the garment and with the opposite face of the fabric predominantly comprised of the yarn  14  as the inner face of the garment. 
         [0020]    Various yarns are deemed to be suitable for these purposes. Specifically, the yarn  12  can be selected from any fibrous material exhibiting satisfactory flame resistance or fire retardant properties. The yarns presently considered most preferable for use in safety apparel applications of the fabric  10  are yarns having a modacrylic fiber content, because modacrylic fibers are known to exhibit flame resistant properties and also to have an affinity to receive dyes which will provide high fluorescence and optimally will meet established standards for minimum high visibility conspicuity, such as standard ANSI/ISEA-107 established by the American National Standard Institute. The yarn  14  appearing at the inner face of the fabric  10  may be selected from any known apparel fiber, whether natural or synthetic in origin, and including by way of example but without limitation cotton, other natural cellulosic fibers such as flax, animal hair (wool, alpaca, cashmere, etc.), silk, polyester, polyamide (nylons), acrylic, rayon and polyimide fibers. Cotton is considered to have the most widespread potential application in the yarn  14 , as it is widely available, relatively inexpensive, and is well established to provide a soft comfortable hand pleasing to the vast majority of apparel wearers. 
         [0021]    Importantly, the yarn  12  does not necessarily have to be formed entirely of a flame resistant fiber such as modacrylic, nor does the yarn  14  necessarily need to be formed entirely of an apparel fiber. For example, for safety apparel applications intended to meet both flame resistance and high visibility standards, it is only necessary that the total content of the fabric, including both yarns  12  and  14 , offers sufficient flame resistance to meet such criteria and that the yarn  12  have a sufficient content of fiber having an affinity for high visibility dyes so as to meet such standards. As will be understood, greater flexibility in the selection of yarns and the yarn content will be available in fabrics intended for safety apparel that is not necessarily to be used in applications requiring high visibility dyeing. By way of example, but without limitation, in fabrics wherein modacrylic fibers are utilized to impart the requisite flame resistance properties, the yarn  12  may have a modacrylic content as low as approximately twenty percent (20%) up to as high as one hundred percent (100%), while the yarn  14  may have an apparel fiber content from one hundred percent (100%) down to as low as approximately fifty percent (50%) with the other fiber content being modacrylic or an alternative fiber, including another flame resistant fiber. One particularly suitable embodiment of the present fabric  10  is fabricated of a blended staple fiber spun yarn as the yarn  12  comprised of approximately ninety percent (90%) modacrylic fibers and approximately ten percent (10%) polyester fibers (which may be a flame resistant polyester), and blended staple fiber spun yarn as the yarn  14  comprised of approximately fifty percent (50%) cotton and approximately fifty percent (50%) modacrylic fibers. 
         [0022]    Advantageously, the present invention accordingly provides a fabric  10  having one face which will offer both a high level of flame resistance capable of meeting the ASTM F-1506 standard and also having an affinity for dyeing by high visibility fluorescent dyes capable of meeting the ANSI/ISEA-107 standard, while the yarn  12  which impart these properties are separated from the body of a wearer by the yarn  14  predominantly forming inner face of the fabric  10  which by contrast impart a hand comparable to normal apparel and avoiding the stiffness and abrasiveness of modacrylic fibers. As such, the fabric  10  of the present invention overcomes the disadvantages of known safety apparel fabrics and is expected to achieve a much wider acceptance and use in the safety apparel industry. 
         [0023]    It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes, of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiment, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.