Abstract:
A composite seam system including a narrow weld bead joining two panels of fabric and a seam tape applied thereon. The applied seam tape comprises a top layer, a reinforcing layer and an adhesive layer melted through the reinforcing layer and connecting the top layer to the fabric panels over the weld bead. The narrow weld bead and the small seam allowance of the fabric panels it joins allows the seam tape to be secured over the weld bead to the fabric panels while lying in a flat plane. The use of a narrow reinforcing layer of woven polyester, nylon or non-woven ultra-fine fibrous material in the seam tape allows the seam tape to be flexible enough to move with the fabric it joins, reducing the incidence of tape edge abrasion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is a continuation of U.S. application Ser. No. 10/906,392, filed Feb. 17, 2005, which claims the benefit of U.S. Provisional Patent Application No. 60/578,760, filed Jun. 9, 2004. The entire content is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Garments designed for the outerwear market can be divided into several main categories including hard shell and soft shell garments respectively. In general, hard shell garments may be distinguished by the inclusion of a waterproofing barrier such as an applied coat of urethane. While soft shell garments can include tightly woven fabrics giving the garment a measure of water repellency, they are generally not completely waterproof. Fleeces having soft fabric which is generally of a knit construction are also used in the outerwear market, and these too are normally not waterproof to the degree that hard shell garments are. Because hard shell garments are used during athletic and outdoor activities, it is desirable that they be light, rugged, have good waterproof characteristics and feature a moisture transfer membrane or the like for moisture management. In addition, from the manufacturer&#39;s point of view it is desirable that these garments be relatively simple to manufacture. 
         [0003]    The method of joining panels of fabric to assemble a complete garment can be just as important to that garment&#39;s overall characteristics as the type of fabric used in that garment. While several prior art methods exist for forming seams in hard shell garments, each has its drawbacks. Simple threaded stitching, while commonly used in the garment industry, is problematic in hard shell garments because a completed stitch leaves a bulky seam in the otherwise lightweight fabric of a hard shell garment. Furthermore, the passage of the needle through the fabric of the garment compromises the waterproof nature of the fabric, necessitating the application of a seam tape secured with an adhesive over the stitched seam to ensure a waterproof seal. 
         [0004]    However, gluing a length of seam tape over the stitched seam creates a new problem. Namely, a sewn and taped seam tends to be rather stiff. The differential in stiffness between the taped seam formed by this process and the lightweight fabric joined by the sewn and taped seam leads to a phenomenon known as edge abrasion. 
         [0005]    Because the region of the seam is much bulkier than the fabric panel which it joins, it causes a region of wear to build up just at the point where the fabric panel meets the taped seam. The continual flexing of the loose fabric against the stiff edge of the taped seam and any external abrasion causes the fabric to wear through at that point, reducing the life of an otherwise serviceable garment. 
         [0006]    Alternatively, manufacturers have employed adhesives to join panels of fabric in a “stitchless” garment. Typically, what is known as a lap seam is made when two pieces of fabric are precut and overlapped. The pieces are secured with an adhesive applied in the area of overlap, which in some instances may require heating to fully interlock with the fibers of the fabric pieces. 
         [0007]    However, the fabrics used in hard shell garments are usually either very tightly woven and/or have a durable water repellent (“DWR”) finish applied to the fabric surface to provide waterproofing for the fabric. A fair amount of adhesive must be applied to find purchase and make a bond of sufficient strength with a fabric having such a weave or finish, making the overall seam that much stiffer once the adhesive has solidified. As such, this method of stitchless garment construction can create an even stiffer seam than that of the sewn and taped seam described above, and so garments constructed with this process can suffer from the problem of edge abrasion to an even greater degree. Also, some fabrics cannot be reliably bonded in this manner and can fail in use. 
       SUMMARY OF THE INVENTION 
       [0008]    In an ideal shell garment the region of the seam, while maintaining the waterproof nature of the panels of fabric joined thereby, is no more stiff than these panels. As such, the garment as a whole is able to flow and flex evenly while worn and areas of wear do not concentrate along the seams. When a lap glued seam or seam tape secured with a large amount of adhesive is employed, the garment diverges considerably from this ideal. The present composite seam system features a lighter, softer seam construction having significantly less bulk which reduces the tape edge abrasion problem considerably. 
         [0009]    The present composite seam system may be used to join various types of hard shell fabrics. In alternative embodiments, the present composite seam system may be used to join synthetic woven fabrics, non-woven fabrics, or knit fabrics including fleeces. In alternative embodiments, these fabrics may be provided with water resistant or waterproof laminates or coatings, and may include a tricot scrim laminated to the face of the fabric. 
         [0010]    In one embodiment, the layered fabrics to be joined in the composite seam are first secured to each other with a weld bead. The weld bead is used to tack the two panels of fabric in place for the later application of a length of seam tape, and/or to protect the edges of the fabric panels from wear once the taped seam is in place. Because the edges of the two joined fabric panels are joined by the weld bead and any seam allowance remaining thereafter is located beneath the taped seam, the edges of the fabric are subjected to very little wear and thus maintain their integrity. Shell garments seamed with just a glued lap joint are prone to experiencing abrasion and unraveling of the exposed edges of their fabrics. 
         [0011]    In another embodiment, the composite seam system includes a very narrow sonic weld bead joining two panels of fabric, and a seam tape applied thereon. The applied seam tape comprises a top layer, a reinforcing layer and an adhesive melted through the reinforcing layer and connecting the top layer to the fabric panels over the sonic weld bead. The narrow sonic weld bead and the small seam allowance of the fabric panels it joins allows the seam tape to be secured over the sonic weld bead to the fabric panels while lying in a flat plane. This, coupled with the inelasticity of the seam tape across its width provides a completed seam that evenly transfers force through the seam tape from one fabric panel to the next without allowing a substantial portion of that force to be transferred to the sonic weld bead. 
         [0012]    The inelasticity of the seam tape is dependent in part on the materials comprising the reinforcing layer used in between the sonic weld bead and the top layer. This reinforcing layer can be a woven polyester, nylon or non-woven ultra-fine fibrous material sufficiently inelastic across its width to prevent the tape from stretching when subjected to a transverse load. 
         [0013]    In an exemplary embodiment of the present composite seam system, the seam tape used has the same modulus of elasticity both across its width and along its length. In an alternative embodiment, the seam tape is provided with a lower modulus of elasticity along its length than across its width. This will allow the seam tape to stretch along its length. The seam tape may need to bend around corners and/or pass through angles when being applied to the garment, and a seam tape that had no give along its length would be difficult to apply under these circumstances. 
         [0014]    The narrow sonic weld bead, small seam allowance, and the materials used in the seam tape provide a relatively thin seam tape that is less stiff, which accordingly reduces the incidence of tape abrasion for the completed seam. 
         [0015]    In another embodiment, a composite seam system used for joining two pieces of fabric includes two pieces of fabric fused together at a seam and a seam tape laid over the seam and covering a portion of each of the two pieces of fabric. The seam tape in turn comprises a reinforcing layer, a top layer laid over the reinforcing layer, and an adhesive bonded to the top layer and passing through fibers of the reinforcing layer to attach to the two pieces of fabric. In an alternative embodiment, the seam tape is dimensionally stable so as to take up substantially the full load applied across the seam. For example, the seam tape comprises a top layer and an adhesive secured to the top layer, wherein the seam tape is dimensionally stable. The seam may also be a sonic weld bead, e.g., less than about one millimeter in width. 
         [0016]    In another embodiment, the invention includes a particularly narrow seam tape as described herein, for example between about six to about eleven millimeters wide. In yet another embodiment, the invention includes a seam tape as described herein having a reinforcing layer below a top layer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a cross-sectional longitudinal view of a prior art seam tape; 
           [0018]      FIG. 2  is a cross-sectional end view of a seam tape for use with the present composite seam system; 
           [0019]      FIG. 3  is an isometric view of the seam tape of  FIG. 2 ; 
           [0020]      FIG. 4  is an isometric view of the present composite seam system showing a seam tape securing two fabric panels; 
           [0021]      FIG. 5  is an isometric view of an alternative embodiment of a seam tape for use in the present composite seam system. 
           [0022]      FIG. 6  is an isometric view of a further alternative embodiment of a seam tape for use in the present composite seam system. 
       
    
    
       [0023]    Before any embodiment of the invention is explained in detail it is to be understood that the invention is not limited in its application to the exemplary details of construction and arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of alternative embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the terminology used herein is for the purpose of illustrative description and should not be regarded as limiting. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    With reference to  FIG. 1 , a cross-sectional longitudinal view is shown of a prior art seam tape  100  having a polyurethane layer  110  and an adhesive layer  130  secured below it. On the opposite side of the polyurethane layer  110  is provided an adhesive  120 . This adhesive  120  secures a knit tricot layer  140  to the polyurethane layer  110 . While this knit tricot layer  140  provides abrasion resistance for the seam tape  100 , it is rather elastic, having a modulus of elasticity of less than 1,900 psi and so cannot add much strength to a completed seam. 
         [0025]    In contrast,  FIG. 2  shows a seam tape  200  for use with the present seam system. The seam tape  200  is a multi-layer construction and includes a top layer  210 , an adhesive layer  230  and a reinforcing layer  240 . 
         [0026]    The top layer  210  is in various alternative embodiments a urethane laminate, mylar, polyester or any flexible plastic material. The top layer  210  is provided for strength, abrasion resistance, and waterproofing purposes. In an exemplary embodiment, the top layer  210  is between twenty and fifty microns thick. 
         [0027]    Below the top layer  210  is an adhesive layer  230 . In one embodiment, this adhesive layer  230  is chemically bonded and chemically compatible with the top layer  210 . Accordingly, in an exemplary embodiment if the top layer is a urethane laminate, the adhesive layer comprises a thermoplastic urethane layer. In an exemplary embodiment, the adhesive layer  230  is between seventy and one hundred forty microns thick. 
         [0028]    Below the adhesive layer  230  is a reinforcing layer  240 . In various alternative embodiments, the reinforcing layer  240  comprises woven polyester, nylon, kevlar or another material sufficiently inelastic across its width so that the seam tape  200  as a whole exhibits substantially no strain across its width when subjected to loads caused by normal wear. In an exemplary embodiment, the reinforcing layer  240  is between one hundred and one hundred fifty microns thick. In a more particular exemplary embodiment, the reinforcing layer  240  may be a  30   d × 30   d  polyester weave with a count of 96×96 yarns per inch. 
         [0029]    In an alternative embodiment, the reinforcing layer  240  need not be as wide as the other layers of the seam tape  200 . As such, the seam tape  200  can be made even thinner and less stiff at its edges, further reducing the incidence of tape edge abrasion in the present composite seam system. Very narrow seam tapes  200  and reinforcing layers  240  can be used in the present composite seam system. In one embodiment, the seam tape  200  is six millimeters wide and the reinforcing layer  240  is four and a half up to about six millimeters wide. In another embodiment, the seam tape  200  is nine millimeters wide and the reinforcing layer  240  is six up to about nine millimeters wide. In yet another embodiment, the seam tape  200  is eleven millimeters wide and the reinforcing layer  240  is six up to about eleven millimeters wide. 
         [0030]    In an alternative embodiment, the seam tape  200  may be provided with a backing paper  250  covering the reinforcing layer  240  to protect it up until the point at which the seam tape  200  is ready to be applied over a sonic weld bead. At this point the backing paper  250  can be removed and discarded. In an additional alternative embodiment, the seam tape  200  can be provided with a hydrophilic layer  220  on the top layer  210 . This hydrophilic layer  220  is preferably a pattern of material printed on the top layer  210 . This hydrophilic layer  220  creates an uneven surface which helps moisture move along the surface of the seam tape  200 . 
         [0031]    The seam tape  200  is shown before application to a garment. As will be shown in the following figures, the arrangement of the layers of the seam tape  200  changes as the seam tape  200  is bonded with another material. Specifically, heat is applied to the seam tape  200  to melt the adhesive layer  230  causing it to flow through the reinforcing layer  240  and interact with the material to which the seam tape  200  is applied. 
         [0032]    With reference to  FIG. 3 , an isometric view of the seam tape  200  is shown having a top layer  210 , an adhesive layer  230 , and a reinforcing layer  240 , but without the hydrophilic layer  220  or the backing paper  250 . 
         [0033]    With reference to  FIG. 4 , an isometric view of the present composite seam system shows a seam tape  420  securing two fabric panels  400 . In an exemplary embodiment, the fabric panels  400  comprise three layers. An outer layer comprises a lightweight rip stop nylon or polyester. This outer layer provides the panel  400  with strength as well as abrasion resistance and water repellency. The outer layer may include a DWR finish to provide water repellency for the fabric panel  400 . 
         [0034]    A middle layer comprises a urethane laminate, a layer of polyester or the like. This middle layer is provided to enable the transport of moisture away from the skin of the user, and for additional waterproofing. An inside layer is preferably provided by a pattern of a hydrophilic material printed on the middle layer. This pattern of hydrophilic material creates an uneven surface which helps moisture move along the inside of the fabric; the side that would contact a user&#39;s skin. Otherwise, this moisture tends to bead up, causing the fabric to feel clammy and stick to a user&#39;s skin. Alternatively this bottom layer can be a lightweight polyester or nylon mesh fabric, or tricot. This layer adds durability while serving the same function of moisture movement. 
         [0035]    The fabric panels  400  as a whole are fairly light. In an exemplary embodiment, the fabric panels  400  are comprised of a material weighing between one and ten ounces per square yard. In an alternative embodiment, the fabric panels  400  are comprised of a material weighing about 1.9 ounces per square yard. In a further alternative embodiment, the fabric panels  400  are comprised of a material weighing about 2.4 ounces per square yard. 
         [0036]    The fabric panels  400  are fused together at their edges by a sonic weld bead  410 . In an exemplary embodiment, a commercially available sonic welder may be used to provide the sonic weld bead  410 . The sonic welder may be used with a head having integral welding and cutting functions. The sonic weld bead  410  is formed as the head of the sonic welder passes high frequency waves through the fabric panels  400  to be joined. These waves vibrate the fabric panels  400 , creating heat through the friction of one fabric panel  400  on the other. The sonic welding process essentially melts or otherwise fuses the edges of the fabrics together. The head of the welder may comprise a wheel having a profile thereon which determines the width of the sonic weld bead  410  made, as well as being made sharper on one side so that extraneous portions of the fabric panels  400  are trimmed off on the waste side of the sonic weld bead  410  at the time the sonic weld bead  410  is made. In an exemplary embodiment of the present invention, the width of the sonic weld bead  410  itself is very small, preferably about one millimeter or less. In a further exemplary embodiment, little or no seam allowance remains beside the sonic weld bead  410  after its formation. 
         [0037]    By this process, the edges of the two fabric panels  400  have been sealed together. The sonic weld bead  410  is not necessarily waterproof, nor is it strong enough alone to hold the fabric panels  400  together under normal wear. Accordingly, a seam tape  420  may be applied over the sonic weld bead  410  to make up for these shortcomings. In addition to ensuring that the cut edges of fabric panels  400  that do still remain along the seam allowance above the sonic weld bead  410  will be hidden under this tape, the sonic weld bead  410  also holds the panels of fabric panels  400  in position during manufacture to allow the seam tape  420  to be properly applied. 
         [0038]    The seam tape  420  may be applied over the sonic weld bead  410  using commercially available machines. As mentioned above, in an exemplary embodiment, the seam tape  420  comprises multiple layers. A top layer  450  is provided of urethane laminate, mylar, polyester or any flexible plastic material for abrasion resistance and to give the seam tape  420  some mechanical stability. The top layer  450  may also have printed thereon a hydrophilic material to aid in moisture transport and to improve the surface feel of the seam tape  420 . 
         [0039]    Beneath the top layer  450  an adhesive layer  430  is applied. The adhesive layer  430  may be chemically bonded to the top layer  450  of the seam tape  420 . In a preferred embodiment, the adhesive layer  430  is chemically compatible with the top layer  450  to aid in this bond. For example, if the top layer  450  were a urethane layer, the adhesive layer  430  may be a thermoplastic urethane (“TPU”) layer. If the top layer  450  were a polyester layer the adhesive layer  430  may comprise a thermosetting polyester. In a further preferred embodiment, the top layer  450 , adhesive layer  430  and the top surface of the fabric panels  400  are all chemically compatible, for example, each may be comprised of urethane based materials. 
         [0040]    A reinforcing layer  440  is provided below the adhesive layer  430 . Some prior art seam tapes have been provided for waterproofing purposes only, or to the extent that a reinforcement was used it comprised a knit tricot layer located on the outside of the seam tape. Knit tricot is a relatively stretchy material and as such, would not provide the seam tape  420  with the strength necessary to shelter the sonic weld bead  410  from higher transverse tensile forces across the seam tape  420 . To this end, the seam tape  420  comprises a reinforcing layer  440  of woven polyester, nylon, kevlar or another material affording the seam tape  420  a high modulus of elasticity. 
         [0041]    In one embodiment, the seam tape  420  has a modulus of at least 5,000 psi and a breaking strength of at least 15 pounds per linear inch. In another embodiment, the seam tape  420  has a modulus of at least 10,000 psi and a breaking strength of at least 20 pounds per linear inch. As such, the seam tape  420  as a whole exhibits substantially no strain across its width when subjected to loads caused by normal wear. The reinforcing layer  440  allows the seam tape  420  to evenly take up substantially all the load applied across the seam when the two fabric panels  400  are pulled apart, shielding the sonic weld bead  410  from experiencing the majority of this load. 
         [0042]    In an alternative embodiment, the reinforcing layer  440  need not be a woven material, rather it may be comprised of a microfiber material, such as any of the microfiber materials disclosed in U.S. Pat. No. 6,048,810 to Baychar (incorporated herein by reference). 
         [0043]    In an alternative embodiment, the adhesive layer  430  may be provided below the reinforcing layer  440 , which in turn is provided below the top layer  450 . In another alternative embodiment shown in  FIG. 5 , a seam tape  500  includes a reinforcing layer  530  embedded within a top layer  510 . An adhesive layer  520  is below the reinforcing layer  530 . 
         [0044]    In yet another alternative embodiment shown in  FIG. 6 , the seam tape  600  includes a top layer  610  and an adhesive layer  620 . The top layer  610  is comprised of a dimensionally stable oriented polymer of a similar elasticity to the reinforcing layers  440  and  530  of previous embodiments. As such, this embodiment dispenses with the need for a separate reinforcing layer entirely. Alternatively, a separate reinforcing layer can remain and be comprised of the dimensionally stable oriented polymer mentioned above. 
         [0045]    In one embodiment of the present composite seam system, when the seam tape  420  is applied over the fabric panels  400  and heated, the adhesive layer  430  melts and a portion of the adhesive runs through the reinforcing layer  440  and onto or into the surface of the fabric panels  400  to secure thereto and/or interlock therein. In this manner the adhesive layer  430  may provide a contiguous bond between the fabric panels  400  and both the top layer  450  and the reinforcing layer  440 . The bond formed creates a waterproof seal and is sufficiently strong to allow the seam tape  420  to take up substantially all of a transverse load applied across the fabric panels  400 . 
         [0046]    In a preferred embodiment, the seam tape  420  sits flat against the fabric panels  400 . Were the seam tape  420  to sit high on the fabric panels  400  in a domed position, there would be some amount of give to the seam as seam tape  420  flattened out under the application of a tensile load across the seam. This would have the similar effect to providing a highly elastic material for the reinforcing layer  440  such as knit tricot or the like. 
         [0047]    This bit of give to the seam tape  420  could allow a substantial portion of that load to transfer to the sonic weld bead  410  as it took up the slack caused by the high position of the seam tape  420 . This load could potentially cause the sonic weld bead  410  to fail, exposing the edges of the fabric panels  400  joined thereby to abrasion and wear. 
         [0048]    This flat profile is made possible both by the lightweight reinforcing layer  440  and the other materials comprising the seam tape  420 , and by the method used to form the sonic weld bead  410 . In a preferred embodiment, the sonic weld bead  410  is formed by a sonic welder having a head which provides a sonic weld bead  410  of one millimeter or less, and which concurrently trims off substantially all of the seam allowance. In an alternative embodiment for use with heavier fabric panels  400  a two millimeter wide sonic weld bead  410  is provided and a seam allowance of two millimeters is provided to ensure that the sonic weld bead  410  lies flat against the fabric panels  400 .