The invention relates to a fabric woven from composite elastic yarns, which comprise inelastic yarns of nylon and cotton and elastic yarns, and inelastic yarns comprising nylon and cotton. The elastic yarns may comprise spandex (or elastane) and more generally polyurea-urethane polymer. LYCRA® brand (from INVISTA® S.à r.l.).of spandex is such a yarn. Other elastic yarns may comprise polyester polymers in the form of bicomponent filaments. The fabric of the invention is suitable for use in the manufacture of garments used for combat uniforms as well as for civilian applications. A fabric comprising about 2% to about 4% by weight of elastic woven with 50 wt. % nylon/50 wt. % cotton yarn has been demonstrated to provide from about 20 to about 50% fabric stretch. Fabric qualities such as breaking strength, tear strength, air permeability and abrasion resistance are maintained or improved over known nylon/cotton fabrics, making the fabric of the invention desirable for applications such as military uniforms and other civilian applications. The invention also relates to methods for preparing such fabrics, and garments made from the stretchable fabrics.
1. Field of the Invention
Combat uniforms have special design and functional needs due to the wide variety of activities that the wearer is engaged in and environments that the wearer is exposed to. Combat uniforms must be designed to provide the wearer a wide range of motion in order for the wearer to perform a variety of activities. Additionally, the fabric used in combat uniforms should provide some protection for the wearer against cold or heat, chemical exposure and should also exhibit good breaking, tear and abrasion resistance for durability as well as air permeability. Further, the fabric must be capable of being dyed for camouflage purposes.
Over time, fabrics and uniform designs have been developed that are advantageous for use as combat uniforms. A particularly useful fabric that has been widely used is NYCO, a 50 wt. % nylon (such as nylon 6,6) and 50 wt. % cotton prepared by spinning the nylon staple fibers with the cotton in such a way that the modulus of the nylon is consistent with that of the cotton.
Due to the qualities of prior known fabric used in combat uniforms, the uniforms typically had to be designed to be loose and baggy on the wearer. Such loose and baggy designs, however, require more fabric than is needed which can have undesirable side effects such as increased overall garment weight. Additionally, a number of wearers of combat uniforms were of the opinion that previous known uniform designs and fabrics had too much fabric to tuck into boots yet did not have enough fabric to allow easy bending of the knees and other body areas such as the back and elbow. Also, uniform designs using Velcro® to hold sleeves in place have been found to be restricting when the wearer reaches for an object.
Studies by Kirk and Ibrahim, Fundamental Relationship of Fabric Extensibility to Anthropometric Requirements and Garment Performance, Textile Research Journal, January 1966 36(1), the disclosure of which is incorporated by reference, measured strain areas of the body in the knee, seat, back and elbows by studying skin stretch at regular intervals. They determined that local skin stretch can vary from 15% to 50% for these body areas.
Based on extent of skin stretch, fabric stretch levels necessary to accommodate skin stretch can be determined. Garment design parameters bear on this determination. For example, conforming body garments require greater fabric stretch levels than looser fitted garments. Factors to be considered include fabric friction, contact points of the garment with the body, fabric stiffness and fabric stretch.
2. Description of Related Art
NYCO fabrics are made with staple yarns of cotton blended with specially engineered nylon staple fibers. NYCO staple yarns and methods of making and using such yarns have been previously disclosed in U.S. Pat. Nos. 3,044,250, 3,188,790, 3,321,448 and 3,459,845 issued to Hebeler; and 5,011,645 issued to Thompson, Jr., the specifications of which are incorporated by reference. The specially engineered nylon fibers have been found to have an equal or superior load-bearing capacity at the break-elongation characteristic of the natural fiber with which it is blended comparable to that of the natural fiber, improving the strength of blends of cotton and the high load-bearing nylon staple. This in turn provides substantial improvement in abrasion resistance and pilling resistance over previously known nylon/cotton blends.
NYCO fabrics continue to be used today for combat uniforms. For example, U.S. Pat. No. 6,805,957, issued to Santos et. al., and U.S. Patent Application Publication No. U.S. 2004/0209051 A1, in the name of Santos et. al. (together, “Santos”), the specifications of which are incorporated by reference, disclose camouflage pattern systems for military and civilian applications as well as techniques for printing the camouflage pattern onto fabric. The preferred fabric disclosed in Santos comprises a NYCO fabric of approximately 50±5% polyamide (nylon type 6,6 manufactured by INVISTA S.à.r.l. as type 420, with a denier per filament of between 1.6-1.8), with the remaining percentage combed cotton. It is also disclosed that other cellulosic fibers, such as Lyocell, can be used instead of cotton. The preferred weave is left-hand twill or twill derivative, although it is disclosed that other weaves may be used. The disclosed weight of the preferred fabric is 6.0-6.6 oz/yd2. (203 g/m2 to 224 g/m2).