Abstract:
A family of composite fabrics is disclosed, such fabrics comprising a relatively thick textile substrate or base to which is attached a sheer fabric, and a method for making same. Contours or three-dimensional patterns associated with the surface of the base to which the sheer fabric is attached are visible through the sheer fabric, imparting to the composite a decorative, three-dimensional quality that is both original and desirable.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to and benefit of U.S. Provisional Patent Application Ser. No. 60/547,242, 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 textile substrate or base to which is attached a sheer fabric, and a method for making same. Contours or patterns associated with the surface of the base to which the sheer fabric is attached are visible through the sheer fabric, imparting to the composite a decorative, three-dimensional quality that is both original and desirable. Additionally, it has been found that, by the addition of the sheer fabric, such composite generally resists certain kinds of abrasion, as compared with the base alone.  
         [0003]     Optionally, one or more additional fabrics or substrates may be attached to the base, on the surface opposite that to which the sheer fabric is attached, thereby constructing a multi-layered sheet composite. Such optional additions may provide dimensional stability, 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 4 , as referenced in the description that follows, is summarized below.  
         [0006]      FIGS. 1 and 1 A diagrammatically depict two embodiments of a composite fabric constructed in accordance with the description herein. In  FIG. 1 , the base fabric  20  is contoured; in  FIG. 1A , the base fabric  20 A is planar, but has been patterned to appear contoured. Both  FIGS. 1 and 1 A can be said to involve base fabrics that appear to exhibit local contouring—in the case of  FIG. 1A , the appearance is deceptive.  
         [0007]      FIGS. 2A through 2C  depict, in cross-section, three exemplary composite fabrics of the kind described herein.  FIGS. 2A and 2C  generally correspond to the embodiments depicted in  FIGS. 1 and 1 A, respectively.  
         [0008]      FIGS. 3A and 3B , and  FIGS. 4A through 4C , are process flow diagrams depicting steps, including alternative and optional steps, by which the fabric exemplified in  FIGS. 1 through 2 C may be manufactured.  FIGS. 3A and 3B  are directed to the formation of the base fabric component, including any additional layer or component added to the back of the base fabric;  FIGS. 4A through 4C  are directed to the formation of the sheer fabric component and the attachment of the sheer fabric to the face of the base fabric. In each of these Figures, 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 producing topographically patterned (i.e., non-planar) constructions (e.g., circular knitting, tricot knitting, or the other processes set forth in  FIG. 3A ), or with finishing techniques such as those set forth in  FIG. 3B .  
         [0011]     Sheer fabric, as the term is used herein, shall refer to fabric having a relatively low weight and a relatively open construction, allowing it to readily transmit light. When placed in contact with the face of a base fabric, a sheer fabric permits at least portions of the face of the base fabric to be seen through the sheer fabric under appropriate lighting conditions.  
         [0012]     The terms “face” and “back” shall refer to respective opposing surfaces of the base or sheer substrates. As shown in  FIGS. 2A through 2C , the face of base fabric  20  is the upper-most surface  22 , with which the sheer fabric  30  is associated. The back  24  of base  20  is the lower surface of the base, to which any optional back coating or other type of supporting or stabilizing structure may be attached, as by adhesive layer  42 . The face of sheer fabric  30  is the upper-most surface depicted in  FIGS. 2A through 2C ; the back of shear fabric  30  is that surface shown in the Figures to be in contact with adhesive layer  32 .  
         [0013]     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. 2A and 2B , T 1  refers specifically to the maximum uncompressed thickness of the base (i.e., peak-to-back thickness) and T 2  refers to the minimum uncompressed thickness of the base—measured at the bottom of the deepest valley to the back—in situations where the base is locally contoured.  
         [0014]     The composite shown in  FIG. 1  is comprised of a relatively thick substrate or base  20 , having a contoured face  22  to which is attached a sheer covering fabric  30 . 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 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  
         [0015]     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.).  
         [0016]     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. This step is generally recommended in cases where a substantially uniform base fabric color is desired, or where yarns particularly suited to solution dyeing (e.g., polypropylene) are used. Where a multi-tone effect to complement the contoured surface is desired, the yarn dye step may serve to define one of the colors in a multi-tone color scheme created by one or more optional dyeing or patterning steps (see Step  70 ) following Step  60 .  
         [0017]     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, for those embodiments in which the base fabric is actually contoured (rather than merely being patterned to give the appearance of being contoured, as explained below), 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. 2A through 2C ) 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 these skilled in the art to be necessary to provide the fabric in the desired form is implicit in Step. 60 .  
         [0018]     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.  
         [0019]     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 or melting (e.g., Step  70 A, as, for example, is disclosed in commonly assigned U.S. Pat. No. 5,148,583, hereby incorporated by reference), 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, hereby incorporated by reference), yarn deformation, as by, for example, embossing (Step  70 C), and yarn melting or degradation (e.g., Steps  70 F through H). 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.  
         [0020]     Among the various optional treatments shown at Step  70 , Step  70 E merely involves the application of one or more dyes to the surface of the base fabric in a pattern configuration. This may be achieved through any of several well-known processes, such as by screen-printing or by the application of metered quantities of colorants from individual, computer-controlled dye nozzles such as disclosed in commonly-assigned U.S. Pat. No. 4,202,189. If the base fabric was formed having a locally contoured face, the patterning can be done either in registration with such contours, or in some other configuration that is complementary or aesthetically desirable, as, for example, in a manner that serves to augment or exaggerate the contoured appearance of the base fabric. Alternatively, the patterning can simply be decorative in the ordinary sense. In the case where the base fabric was formed with a planar, non-contoured face (e.g., as depicted in  FIGS. 1A and 2C ), the patterning can be done so as to provide the appearance of a locally contoured surface, through use of shadow and highlight, or through use of trompe l&#39;oeil techniques.  
         [0021]     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 composite fabric. Typically, this difference in thickness or elevation (diagrammatically depicted in  FIGS. 2A and 2B  as ΔT) will be at least 0.2 mm, and more typically will lie within the range of about 0.5 mm to about 2.5 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.  
         [0022]     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  . At the other extreme, T 2  for the non-contoured composite of  FIG. 2C  is 100% of T 1  . Because the visual contouring of the base fabric of  FIG. 2C  is achieved wholly through the application of dye in a pattern configuration (as, for example, by step  70 E), the thickness requirements of base fabric  20  can be less than would otherwise be preferred.  
         [0023]     Following such patterning step  70 , the base fabric optionally may be dyed (if not already dyed in Step  70 E), either a solid color or in a pattern (optional Step  72 ). In optional Step  74 , a chemical finish or treatment optionally may be applied by any appropriate means to provide the base fabric with desired water repellency, anti-microbial properties, etc.  
         [0024]     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, film, open or closed cell foam, or 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.  
         [0025]     The specific process flow presented is exemplary and illustrative only, and is not intended to be limiting in any way. For example, it is contemplated that local contouring (Step  70 ) could occur following bonding (Step  78 ). Similarly, face finishing (Step  62 ) could occur following dyeing (Step  72 ). These specific process step sequence changes could occur independently or together in the same process flow. Other such changes may be readily apparent to those skilled in the art.  
         [0000]     Sheer Fabric  
         [0026]     Construction of the sheer fabric useful for the applications described herein is in accordance with the steps depicted in  FIGS. 4A and 4B . Any suitable fibers or yarns may be used, including those discussed in connection with the construction of the base fabric, so long as such yarns or fibers are appropriate for use in forming a sheer fabric of the kind contemplated herein, i.e., one that generally will provide the desired degree of attachment to the base fabric and that will minimize the degree of opacity resulting from its use as a cover over the contoured portions of the base fabric.  
         [0027]     In optional Step  158  of  FIG. 4A , the yarns used to construct the sheer fabric optionally may be dyed, either uniformly or in a pattern configuration, preferably to match or complement the color of the yarns to be used in the accompanying base fabric. When in place over the face of the base fabric, the sheer fabric will obscure, to a greater or lesser degree, the face of such base fabric, depending upon the color and relatively opacity of the sheer fabric, the color and contour of the base fabric, etc. It is contemplated that, in some applications, sheer fabric may be kept in greige form in order to make the sheer fabric as unobtrusive as possible. However, it is recognized that, for some applications, some degree of opacity may be desirable. By appropriate dyeing of the yarns and careful selection and adjustment of the fabric formation process (discussed below), the degree of opacity may be adjusted accordingly. Typically, sheer fabric  30  is preferably capable of transmitting at least 20% of directly incident light, and, more preferably, capable of transmitting at least 30% to 40% of directly incident light, up to a practical maximum of perhaps 60% to 70%.  
         [0028]     Formation of the sheer fabric is represented at Step  160 . As indicated in  FIG. 4A , and as set forth in corresponding fashion in  FIG. 3A  in connection with the formation of the base fabric, a variety of fabrication methods may be used to form the sheer fabric. It is intended that the choice of yarns and yarn weights, when used to form fabric using, for example, a specifically selected fabrication technique selected from those identified at  160 A through  160 E of  FIG. 4A , will result in a fabric that is relatively light transmissive, and that has a weight perhaps within the range of about 5 gms/m 2  to about 100 gms/m 2  and preferably within the range of about 15 gms/m 2  to about 50 gms/m 2 .  
         [0029]     Following fabric formation step  160 , the sheer fabric optionally may be subjected, in optional Step  162 , to one or more conventional face finishing processes such as napping, sanding, brushing, etc., with care needed to avoid unintended physical damage to the fabric. Following such step, the sheer fabric may be heat set (optional Step  164 ) to provide dimensional stability, etc.  
         [0030]     As may be apparent, the processing steps for the sheer fabric bear close correspondence with steps used in the preparation of the base fabric. In optional Step  170 , the sheer fabric may be patterned or contoured, using the techniques described above with reference to Step  70  (identified as  170 A through  170 H, respectively corresponding to Steps  70 A through  70 H, discussed above), with appropriate modifications to operating parameters, etc., to accommodate the nature of the sheer fabric. As mentioned above, other techniques that may occur to those skilled in the art may also be used. The sheer fabric optionally may be dyed (optional Step  172 , corresponding to optional Step  72 , above), perhaps in a pattern to enhance or augment the underlying contouring or patterning of base fabric  20 , or to enhance, augment or mitigate the relative opacity of the sheer fabric. The sheer fabric optionally may also be subjected to a chemical treatment or finish (optional Step  174 ), for the purpose of reducing opacity, providing desired stiffness, enhancing surface smoothness or slickness, imparting water repellency or anti-microbial properties, etc.  
         [0000]     Formation of Composite  
         [0031]     Following Step  174 , the sheer fabric moves to Steps  176  and  178 , in which the sheer fabric is glued, bonded, laminated, or otherwise attached to the face of the fully processed base fabric (the base fabric having either undergone or bypassed one or more of the optional processing Steps  62  through  78  of  FIGS. 3A and 3B ). Such attachment may be permanent, as through the use of a conventional adhesive (applied at optional Step  176 ), or may be achieved through the application of a releasable adhesive (also applied at optional Step  176 ), the latter being preferred. if occasional access to the underlying base fabric is desired. In either case, it is preferred that the adhesive used not render the sheer fabric excessively opaque, so as to obscure totally the face of underlying base fabric  20 . Finally, optional Step  180  provides an opportunity for additional patterning or localized contouring of the sheer+base composite that was formed in Step  178 , perhaps using some of the techniques of step  170 , as appropriate. The final composite product is indicated at Step  182 .  
         [0032]      FIGS. 2A and 2B  depict, in cross section, two extremes in the final configuration of the sheer+base composite formed in Step  178 . In  FIG. 2A , the sheer fabric  30  is attached, via adhesive layer  32 , to only the upper-most portions or peaks of the face  22  of contoured base  20 . The visible contoured face of base fabric  20 , when viewed through sheer fabric  30  and adhesive layer  32 , provides the sheer+base composite with a three-dimensional appearance. This effect has been depicted in  FIG. 1 . The addition of optional back layer  40 , perhaps attached via adhesive layer  42 , may provide the sheer+base composite with qualities or properties useful in, for example, automotive upholstery applications. It should be noted that, due to the planar configuration of the sheer fabric and its capacity to present a low-friction surface, the addition of sheer fabric  30  to contoured base fabric  20  results in a significant increase in the ability of the composite fabric to resist the effects of abrasion. Taber abrasion tests, conducted in accordance with ASTM D 3884 on woven base fabrics in which the contouring was achieved by the incorporation of float yarns in the face of the fabric, indicated that use of a sheer fabric resulted in greater than a 100% improvement in Taber abrasion.  
         [0033]     In  FIG. 2B , the sheer fabric  30  is again attached, via adhesive layer  32 , to the face  22  of contoured base  20 . However, in this case sheer fabric  30  has been made to conform to the local contours of the face of base  20 . The three dimensional nature of the composite is now primarily conveyed by the contoured nature of the sheer fabric  30 , which in turn is determined by the contoured nature of the base  20  to which it is attached. As before, the addition of optional back layer  40 , perhaps attached via adhesive layer  42 , may be added to provide additional suitability of the composite for certain applications.  
         [0034]     Again, the addition of sheer fabric  30  to contoured base fabric  20  results in a significant increase in the ability of the composite to resist the effects of abrasion. As before, Taber abrasion tests, conducted in accordance with ASTM D 3884 on woven base fabrics in which the contouring was achieved wholly by the incorporation of float yarns in the face of the fabric, indicated that use of a sheer fabric resulted in greater than a 100% improvement in Taber abrasion.  
         [0035]     It is anticipated that intermediate configurations of sheer fabric on base fabric, in which sheer fabric  30  conforms only partially to the underlying contours of base fabric  20 , may be employed as well.  
         [0036]     It is foreseen that base fabric  20  may not always be locally contoured. As depicted in  FIG. 2C , as well as  FIG. 1A , the face of the base fabric  20  is not substantially contoured, but rather is dyed in a manner that imparts the appearance of a locally contoured surface (by, for example, a pattern that suggests highlights and shadows or by using trompe d&#39;oeil techniques), which may be observed through sheer fabric  30 . While this technique is primarily intended for use with bases having a face that is essentially flat or smooth, it may also be adapted for use with bases having a locally contoured face. In the former case, the dyed pattern can impart a contoured or three-dimensional character to a face that is essentially two dimensional (i.e., flat and smooth); in the latter case, the dyed pattern may be used to enhance and perhaps exaggerate the existing contours of the face of base fabric  20 .  
         [0037]     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.