Abstract:
A family of composite fabrics is disclosed, such fabrics comprising a relatively thick, contoured textile substrate or base onto which is applied a coating to provide an upholstery fabric having a unique appearance and texture. Surface contours, and in some cases portions of the underlying base fabric over which the coating is applied and subsequently removed through processing-induced abrasion, tend to be visible through breaks in the opaque coating, thereby imparting to the composite a decorative, three-dimensional quality.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to and benefit of U.S. Provisional Patent Application Ser. No. 60/547,243, filed on Feb. 23, 2004, which is hereby incorporated by reference herein. 
     
    
     SUMMARY OF THE INVENTION  
       [0002]     This disclosure relates to a family of composite fabrics comprising a relatively thick, contoured textile substrate or base onto which is applied a coating to provide an upholstery fabric having a unique appearance and texture. Surface contours, and in some cases portions of the underlying base fabric over which the coating is applied and subsequently removed through processing-induced abrasion, tend to be visible through breaks in the opaque coating, thereby imparting to the composite a decorative, three-dimensional quality. In one embodiment, the coated fabric undergoes a dyeing step in which coating material is selectively abraded from the protruding elements of the contoured fabric surface as part of the dyeing step. In another embodiment, the coating is abraded in a separate step, prior to the dyeing step. In either case, the resulting composite fabric has a contoured surface in which the coating largely obscures the underlying base fabric except in places where the coating material has been abraded away. If the coating and the dyeing step involve different colors, a multi-colored effect is obtained. In any case, the resulting composite fabric presents a unique combination of hand and appearance, and one that facilitates repeatable color matches.  
         [0003]     Optionally, one or more additional fabrics or substrates may be attached to the base, on the surface opposite to the coated surface, thereby constructing a multi-layered sheet composite. Such optional additions may provide physical integrity, stability while cutting, padding, etc., to the composite fabric and perhaps better adapt the composite fabric to various upholstery applications, as, for example, in automotive and other transportation applications, interior furnishing applications for domestic or hospitality markets, etc.  
         [0004]     Details of various embodiments and variations of such composite fabrics, and methods for making such fabrics, are explained below, with the aid of the accompanying drawings and definitions. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     The content of  FIGS. 1 through 3 , as referenced in the description that follows, is summarized below.  
         [0006]      FIG. 1  diagrammatically depicts an exemplary contoured base fabric (with an optional backing layer  40 ) prior to the application of a suitable coating composition.  FIG. 1A  depicts the fabric of  FIG. 1  following the application of a suitable coating composition.  FIG. 1B  shows a detail of an edge portion of the coated base fabric of  FIG. 1A .  
         [0007]      FIGS. 2A through 2D  depict, in cross-section, two other exemplary contoured and coated base fabrics; in  FIG. 2A , the fabric was not treated with a chemical finish prior to coating, and the coating has not yet been abraded.  FIG. 2B  shows exemplary results of abrasively treating the fabric of  FIG. 2A —the coating has been occasionally abraded away from around some of the “peak” areas of the contoured face of base fabric  20 .  FIG. 2C  shows a base fabric  20  that was treated with a chemical finish  20  prior to coating.  FIG. 2D  shows exemplary results of abrasively treating the fabric of  FIG. 2C ; the coating  30  has been abraded away to a greater degree from around most of the “peak” areas of the contoured face of the base fabric  20 .  
         [0008]      FIGS. 3A and 3B  are process flow diagrams depicting steps, including alternative and optional steps, by which the fabric exemplified in  FIGS. 1, 1A ,  2 B, and  2 D may be manufactured. In each of the  FIGS. 3A and 3B , dotted lines indicate actions or steps that are individually optional. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0009]     As used herein, the following terms shall have the indicated meanings, unless express language or context otherwise dictates.  
         [0010]     Contoured, locally contoured, or local contouring, as those terms are used herein, shall refer to undulations, depressions, or other sources of surface relief that cause the face or back of a fabric to be non-planar, i.e., to deviate from a smooth planar surface over a relatively localized area, for example, within an area or region of perhaps one or several square centimeters, so as to impart a three-dimensional pattern to the surface of the fabric. Typically, but not necessarily, the contour is replicated regularly throughout the fabric. However, for example, a logo desirably may be reproduced only in selected areas. The depth of contouring (i.e., the maximum difference in elevation or base fabric thickness between high and low contour features, respectively referred to as “peaks” and “valleys”) is intended to be greater than that normally associated with the slightly textured surface common to regular woven or knitted flat fabrics. In such flat woven and knit fabrics, the crossover points of the yarns create the largest “contours” of the fabric, with a depth of contouring measured (as if viewed in cross-section) from the top of the bottom yarn (in the “valley”) to the top of the crossover yarn (on the adjacent “peak”). For example, in a flat woven fabric, it is the elevation change in going from the top of a fill yarn to the top of a warp yarn on the adjacent fill yarn. In contrast, the fabrics discussed for use herein have surface contours that are created periodically, for example, by means of specific construction (use of larger and smaller yarns), using specific fabric formation methods capable of creating topographically patterned (i.e., non-planar) constructions, or with finishing techniques.  
         [0011]     Thickness T, as used to describe a base fabric, shall refer to the uncompressed thickness of the base fabric (i.e. the distance separating the parallel planes that define, respectively, the uppermost surface of the face—the elevation of the highest peak—and the back of the fabric). As shown in  FIGS. 2B and 2D , T 1  refers specifically to the maximum uncompressed thickness of the base and T 2  refers to the minimum uncompressed thickness of the base—measured at the bottom of the deepest valley—in situations where the base is locally contoured.  
         [0012]     The composite shown in  FIG. 1  is comprised of a relatively thick substrate or base  20 , having a contoured face. Optionally, a backing member  40  comprised of, for example, a back coating, an attached scrim, an attached non-woven substrate, or a relatively thin layer of open- or closed-cell foam may be attached to the back of the base  20  in order to give the composite physical integrity, stability while cutting, or necessary weight, to establish a desired barrier for the rear surface of the composite, or to provide some other desirable attribute. Details of each of these components, along with (1) preferred embodiments, (2) process steps in manufacture, and (3) options and alternatives, are discussed below.  
         [0000]     Base Fabric  
         [0013]     Base fabric or substrate  20  may be constructed using any of a wide variety of textile materials, depending upon the desired characteristics of the composite and the selected technique used for constructing the base fabric. For example, fibers or yarns comprised of commonly available materials such as nylon, polyester, polypropylene, or cellulosic materials (e.g., rayon, cotton, etc.) may be used, as well as various engineered materials such as those marketed by Dupont (e.g., Nomex®, Kevlar®, etc.). Possible constructions of base fabric  20  include various types of weaving and knitting, as well as the use of non-woven constructions, as discussed below. Most commonly, base fabric  20  will have a non-pile surface; however, base fabric  20  may have a pile surface that is subsequently contoured or patterned (e.g., via optional Step  70 , also discussed below).  
         [0014]     Looking at  FIG. 3A , Blocks  58  through  64  outline several possible steps by which a suitable base fabric may be constructed. Beginning at optional Step  58 , the selected yarn (or yarns, if different types are used) optionally may be dyed, as where accent yarns in the final product are required or where yarns particularly suited to solution dyeing (e.g., polypropylene) are used. However, in general, it should be emphasized that any such step would be supplementary to the dyeing step of Step  74  following coating, which step is considered a characteristic part of the process disclosed herein.  
         [0015]     Step  60  represents the fabric formation step in which the base fabric is generated. As indicated in  FIG. 3A , this step may involve various forms of knitting, weaving, or the generation of a non-woven substrate. The objective of this step is to form a fabric having a thickness that exceeds most single-component fabrics, and that provides for sufficiently deep contouring to provide the desired visual effect in the completed composite fabric. Generally, the bases contemplated herein will have a minimum uncompressed thickness (indicated at T 1  in  FIGS. 2B and 2D ) not less than about 0.3 mm to about 1.0 mm, with practical maximum thicknesses falling within the range of about 1.0 mm to about 10.0 mm. In many cases, bases in which T 1  falls within the range of about 0.5 mm to about 5.0 mm have been found to be preferable. Although not shown, any slitting or similar operations known by those skilled in the art to be necessary to provide the fabric in the desired form is implicit in Step  60 .  
         [0016]     Following fabric formation Step  60 , the resulting fabric optionally may be subjected to various appropriate face finishing operations, such as napping, sanding, brushing, or the like, as signified in optional Step  62 . The appropriately face-finished fabric then may be optionally subjected to a heat setting step, depicted at  64 , to stabilize the base fabric&#39;s width, shrinkage characteristics, etc., as desired.  
         [0017]     The local contouring of base fabric  20  can be imparted as part of the fabric formation process of Step  60  (e.g., jacquard weaving, dobby weaving, circular knitting, tricot knitting, or Raschel knitting, etc), or can be imparted or enhanced during a subsequent step (such as depicted at optional step  70  in  FIG. 3B ), in which a base fabric that may have been formed with insufficient contouring, or that was formed with a planar surface (e.g., no local contouring) is treated to establish such a locally contoured surface. Individual processes associated within Step  70 , as listed in  FIG. 3B , include localized yarn shrinkage or melting by heated fluid streams (e.g., Step  70 A, as, for example, is disclosed in commonly assigned U.S. Pat. No. 5,148,583), yarn dislocation by high velocity fluid streams (e.g., Step  70 B, as, for example, is disclosed in commonly assigned U.S. Pat. No. 5,235,733), yarn deformation, as by, for example, embossing (Step  70 C), and yarn melting or degradation (e.g., Steps  70 E through G). This collection of techniques is intended to be non-exclusive—it is contemplated that two or more may be used on the same base fabric, and that other conventional processes may readily be used or adapted for use in providing local contouring to base fabric  20  as may occur to those skilled in the art. Fabrics that emerge from Step  60  as locally contoured may also be subjected to one or more of the processes of Step  70  if additional or enhanced contouring is desired.  
         [0018]     The depth of contouring (i.e., the difference in fabric thickness measured at various lateral locations across the face of fabric  20 ) is dependent upon a number of factors, including the initial depth of the base fabric  20  and the visual effect to be achieved with the resulting coated fabric. Typically, this difference in thickness or elevation (diagrammatically depicted in  FIGS. 2B and 2D  as ΔT) will be at least 0.2 mm, and more typically will lie within the range of about 0.5 mm to about 1.5 mm, but could easily be greater, e.g., as much as a centimeter or more, if the base fabric is sufficiently thick and extreme contouring is necessary or desired. For example, if the composite is to be used in applications where sound absorption is important, deep contouring adapted to increase surface area or to accommodate sounds of specific short wavelengths may be used.  
         [0019]     Referring to  FIGS. 2A and 2B , it is contemplated that T 1  have a value that is at least 0.3 mm or greater, and preferably 1.0 mm or greater, with T 2  ranging in value from perhaps 90% of the value of T 1  to perhaps 10% (or less) of T 1 , so long as base  20  maintains sufficient physical integrity to allow for manufacture. It is also contemplated that T 2  could, in fact, be 0%, indicating the case where the base fabric is perforated with holes that extend the entire distance T 1  and that would likely be occluded by the coating.  
         [0020]     Following such contouring step  70 , a chemical finish or treatment optionally may be applied (optional Step  72 ) to the base fabric. In a preferred embodiment, such treatment is comprised of the application (e.g., by spraying, coating, or other conventional means appropriate to the characteristics of the base fabric and the finish) of a fluorochemical that will tend to reduce the degree to which any subsequently applied coating composition (see Step  73 ) adheres to the “peaks” or areas of maximum thickness of base fabric  20 , to be discussed below.  
         [0021]     Generally, repellent fluorochemicals useful in the present invention include any of the fluorochemical compounds and polymers known in the art to impart water- and oil-repellency to fibrous substrates. These repellent fluorochemical compounds and polymers typically comprise one or more fluorochemical radicals that contain a perfluorinated carbon chain having from 3 to about 20 carbon atoms, more preferably from about 6 to about 14 carbon atoms. These fluorochemical radicals can contain straight chain, branched chain, or cyclic fluorinated allcylene groups or any combination thereof. Commercially available examples of repellent fluorochemicals that may be used include, but are not limited to, the Scotchgard™ family of repellent fluorochemicals by 3M, the Zonyl™ family of repellent fluorochemicals by Dupont, the Repearl™ family of repellent fluorochemicals by Mitsubishi International Corporation, such as Repearl® F-8025 or Repearl® F-7000. Other fluorochemicals, such as the Unidyne™ products distributed by Daikin America, Inc. or products distributed by OMNOVA Solutions may also be employed. In addition to fluorochemicals, other repellent chemistry, such as repellent silicones, may also be employed.  
         [0000]     Coating the Face of the Base Fabric  
         [0022]     In Step  73 , the undyed base fabric  20  is coated using any convenient technique (e.g., knife or roll coat) that will accommodate the characteristics of the base fabric and the selected coating composition. However, use of a knife coater has been found to be particularly effective, in that the coating tends to accumulate in the depressions of the contours and is at least partially scraped or otherwise removed from many or most of the countour “peaks” of the base fabric  20 .  
         [0023]     In one preferred embodiment, the coating composition is comprised of a 100% solids silicone coating, such as that distributed by Wacker Chemicals, of Adrian, Mich., as LR3003/10A and LR3003/10B, mixed according to directions. Other types of coatings are contemplated, such as mastics or other materials containing, for example, acrylics, polyurethanes, blocked copolymers, etc., that are individually or in combination capable of providing the necessary viscosity, adhesion, durability, and possibly other desirable characteristics. An example of one such coating is a blocked isocyanate polyurethane, marketed as Impranil®  80  and available from Bayer Chemicals, of Leverkusen, Germany. The selected coating composition may, but need not, contain pigment, depending upon the visual effect desired in the finished fabric. However, in any case, the viscosity of the coating composition, as applied, should be such that the composition flows into the contours of the base fabric, but remains primarily on the contoured surface of the base fabric, i.e., it does not penetrate to a great degree into the underlying structure of the base fabric. Generally, coatings having viscosities within the range of about 80,000 centipoise to about 400,000 centipoise using a Brookfield LV spindle number 4 at 1.5 rpm, and more particularly, between about 200,000 centipoise and about 300,000 centipoise, have been found to produce fabrics having the desirable characteristics described herein. It is contemplated that, depending upon the coating application technology used, the physical construction of the base fabric, the nature of any chemicals previously applied to the surface, and other factors, viscosities falling outside the above-defined ranges may still have the desirable flowable-yet-non-penetrating qualities discussed above. Following application, the coating of choice should be appropriately cured.  
         [0024]     Optional Step  74  provides for use of a separate means to abrade the coated fabric prior to the dyeing step. Such means can comprise use of abrasively coated rolls or other materials, high velocity fluid jets, etching techniques (including laser techniques), sanding, brushing, sand or shot blasting techniques, or other conventional means known to those skilled in the art, including at least some of those described in connection with Step  70 , above. It is also contemplated that washing the coated fabric in a way that causes the fabric to rub against itself or the confines of the washing vessel may produce a desirable degree of coating removal.  
         [0025]     In optional Step  75  in  FIG. 3B , the base fabric carrying the cured coating may be dyed (keeping in mind that, if the base fabric  20  was constructed using dyed yarns, indicated at Step  58 , such dyeing is optional). If abrading Step  74  is used, and coating  30  is already eroded, any suitable dyeing technique may be used. If coating  30  is insufficiently eroded, then use of a jet dyeing technique (or other technique in which the base fabric is tumbled or otherwise manipulated to allow for selective abrasion of the coating) is preferably used. In either case, erosion of the coating  30  allows for preferential dyeing of the underlying fabric base in those areas where the coating has been selectively abraded. If the coating carries a pigment, such dyeing can be in a color that complements or contrasts with the color imparted to the coating.  
         [0026]     Optional Step  76  provides for the application of a coating to the back of the base fabric. Such coating can be comprised of any of a variety of materials, such as PVA, acrylic emulsions, EVA, various block copolymers, polyurethane, and other common or conventional treatments used to back coat textiles, applied, for example, as a hot melt, or in an aqueous or solvent-based solution. Optional Step  78  provides for the bonding or lamination, again to the back of the base fabric, of an additional layer such as, for example, a scrim, an open or closed cell foam, or a non-woven web. It is contemplated that Steps  76  and  78  may be used individually or together in situations where one or more additional layers are desired on the back of the base fabric, perhaps to give the base fabric additional physical integrity, cutting stability, weight, or bulk, to provide a barrier to moisture or a contaminant, or to assist in subsequent parts molding operations, etc.  
         [0027]      FIGS. 2A through 2D  depict, in cross section, two alternative embodiments of the product resulting from the process described in  FIGS. 3A and 3B .  FIG. 2A  depicts a coated base fabric  20  with no chemical finish having been applied prior to the application of coating  30 . Depending upon the choice of coating material, the coating technique used, and other factors, the relative uniformity in coating thickness may vary, but the difference in coating thickness between the “peaks”  32  and the “valleys”  32 A, as indicated, is relatively insignificant.  
         [0028]      FIG. 2B  depicts the fabric of  2 A following an abrasive dyeing step (or following a separate abrading step and a separate dyeing step). The coating  30  is largely intact in the “valley” areas  32 A, and is present, although in somewhat eroded form, on a significant number—perhaps a majority—of the “peaks,” indicated collectively at  32 . The degree to which the coating  30  is eroded depends upon several factors, including the degree of abrasion experienced by the base fabric  20 , the adhesion properties of the coating  30  in relation to the selected base fabric, and the nature of the contouring.  
         [0029]      FIG. 2C  depicts a fabric similar to that depicted in  FIG. 2A , but on which a chemical finish  28  of the kind discussed above has been applied prior to the coating operation. As discussed above in the case of the fabric of  FIG. 2A , the applied coating  30  is more-or-less uniform in thickness, with some accumulation in the valley portions  34 A of the contoured base fabric  20 . Such insignificant non-uniformity is in contrast to the situation depicted in  FIG. 2D , in which the coated base fabric  20  of  FIG. 2C  has been subjected to an abrasive dyeing step (or a separate abrading step followed by a separate dyeing step), with substantial removal of coating  30  in evidence. In the portion of the fabric shown, the coating  30  (as well as the chemical finish  28 ) on each of the “peak” areas  34  has been removed, leaving the underlying base fabric  20  exposed. The degree and lateral extent to which the coating  30  and perhaps the chemical finish  28  is removed is a function of several variables, including (1) the nature of the coating and coating application techniques used, (2) the nature of the dyeing technique used to dye the coated base fabric (e.g., as when jet dyeing techniques are used, and, as part of the process, the coating is abraded from portions of the contoured surface of the base fabric), (3) the use of a separate processing step, discussed above and shown at  74  in  FIG. 3B , in which the coating is selectively removed through sanding, washing, laser etching, use of abrasively-coated rolls (as described, for example, in commonly assigned U.S. Pat. No. 5,943,745, or the like, (4) the nature of the contour of the base fabric (e.g., sharp “peaks” vs. flat plateau areas), or (5) a combination of the foregoing. It is in areas in which the coating (and, most likely, the underlying chemical finish) has been substantially removed (rather than simply thinned), as shown at  34  in  FIG. 2D , in which optional dyeing step  75 , by imparting the selected dye color to such areas, can have a substantial effect upon the appearance of the overall coated fabric.  
         [0030]     The specific embodiments and parameters presented throughout this description are exemplary and illustrative only, and are not intended to be limiting in any way. It is contemplated that other, substantially equivalent materials, configurations, arrangements, parameter values, and specific functions may be substituted without departing from the spirit of the teachings herein. Therefore, it is not intended that the scope of the development disclosed herein be limited to specific embodiments illustrated and described.