Fabrics made from high performance polymer fibers may utilized in a variety of commercial and private end-uses ranging from composites and aircraft to body armor and armored vehicles. Performance textiles are also used across the market to provide fabrics and designs that can withstand heat, abrasions, stains, discolorations, and other environmental assaults. Antiballistic articles or fabrics woven for life protection are used to repel and trap ammunition, shrapnel, or hand driven sharp objects such as knives, awls, shanks and the like. These antiballistic fabrics are typically layered, cut, and stitched in a pattern to construct protective soft armor such as vests, or may be used in the construction of armored vehicles and helmets.
High performance fabrics may be woven in patterns such as plains, twills, baskets, and satins. The warp and fill yarn interlace at right angles, are typically light weight, and preferably have floats extending over multiple yarns. Patterns such as twill and satins have shown improved ballistic performance due in part to the longer floats of a looser weave. For instance, when a projectile hits a protective vest or other article of protective material, the resulting back face deformation is typically reduced in a looser weave than when compared to a plain weave. The main goal of protective armor is to prevent fatalities and minimize damage, injury and blunt force trauma to the person(s) being protected; therefore, it is most desirable utilize a fabric that results in less back face deformation. However, using these type of weaves represents a challenge to armor manufacturers during layering and cutting patterns due to looseness of the fabric structure, fraying, and distortion that causes yarn interlacing to deviate from right angle interlacing. The yarns of these fabrics are not secured as well within the fabric layer and therefore tend to fray and fall apart along the cut edges more easily. For these reasons, these weaving patterns are not widely used in the high performance fabric industry. Although the performance characteristics of the fabric may be enhanced by these particular weaves, the difficulty in handling poses a large problem.
When using a tighter weave, such as a plain weave, the handleablility during fabric construction may be improved over that of a looser weave; however, the performance characteristics may not be up to par for a particular end-use. Furthermore, high performance fabrics constructed from a plain weave or a tight construction may not conform as easily to a particular shape or curvature. When designing vests or other clothing, this characteristic translates to clothing that does not conform as well to a person's body and tends to be very uncomfortable to wear. When military personnel and law enforcement wear antiballistic clothing, maintaining maneuverability is essential; these articles should provide protection, not distraction. Therefore, it would be beneficial to design a high performance fabric of a lower weight and improved comfort that can bend and conform more easily to accommodate both men and women of varying body types and sizes, as well as maintaining the high quality performance characteristics required of these articles.
Given the problems and disadvantages associated with the current art, it would be advantageous to provide a weaving pattern and process that results in a fabric having the handleablility of a tighter weave with the performance characteristics of a looser weave. This fabric would maintain shape and construction during the manufacturing of an end-use product, yet still possess the advantages resulting from the longer float of a looser weave. A further advantage would be improved tightness and stabilization of the fabric, particularly when the fabric is cut and sewn together to form a desired system, yet the fabric may still conform easily to a variety of shapes and curvatures. The weave pattern and process of the present invention provides stability of fabric structure without compromising the quality and performance characteristics of the end-use product.
The present invention consists of a weave pattern and method that provides stability to high performance fabrics, such as fabrics used for life protection (i.e. antiballistic) and composite use. This weave pattern and method is not restricted to high performance fabrics, however, and may be applied to the construction of any type of fabric where improved handleablilty is desired. This invention consists of adding an additional set of yarn in the warp direction, such that there are two sets of warp yarns per fill yarn alternating throughout the structure of the fabric. Set one may consist of any known weave pattern such as plain, twill, basket, satin, or another pattern. Set two is preferably a plain weave in the warp direction, alternating over and under each fill yarn, but may be any weave variation provided it is inserted in the fabric such that it interrupts the pattern of set one.
This introduction of a second set of warp yarn locks the fill yarns in place, subsequently interlocking and stabilizing the fabric pattern. This stabilization increases tensile strength, tightness, stiffness, and also improves the handling and cutting of the fabric by resulting in decreased fraying and fiber loss during product construction. Also, the fabric maintains proper shape and form due to the 90 degree interlacing of warp and fill yarns. This interlacing is maintained and does not suffer from the distortion that may be found in looser weaves with a longer float. In this way, the fabric may have the enhanced performance characteristics of a looser weave in combination with the enhanced handleability of a tighter weave.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
The ratio range of warp set one to warp set two is preferably 2:1 to 5:1, more preferably 2:1 to 3:1, most preferably 2:1. For example: in a 2:1 ratio, there would be two yarns of warp set one, followed by one yarn of warp set two, followed by two yarns of warp set one, followed by one yarn of warp set two, and so on. In a 3:1 ratio, there would be three yarns of warp set one, followed by one yarn of warp set two, followed by three yarns of warp set one, followed by one yarn of warp set two, and so on. If a ratio below 2:1 is used, the resulting fabric weave would most likely mimic the qualities of a typical plain weave without the added advantages of a loose weave. Similarly, if a ratio greater than 5:1 is used, the handelablility of the resulting fabric may decrease beyond an advantageous extent, thus negating the favorable construction qualities obtained through the introduction of warp set two.
A preferred ratio of 2:1 is illustrated in
Warp set one, warp set two, and the fill yarn may consist of the same or different materials, sizes, and numbers of fibers. For example, the fill yarn and warp set one may be made from fibers of a first material such as an aramid, while warp set two may be made from fibers of a second material such as ultra high molecular weight polyethylene (UHMWPE); the resulting fabric being composed of both aramid and UHMWPE fibers. Alternatively, the fill yarn and both sets of warp yarn may all be fibers of a first material; the resulting fabric being composed of all aramid fibers or all UHMWPE, for example.
Preferred fibers include, but are not limited to, high tenacity polymer fibers, such as various aramid fibers, high performance polyethylene fibers, and the like. Due to their remarkably high tensile strength-to-weight ratio, such fibers have many applications such as body armor. Specific high tenacity fibers suitable for the composite material of the present invention include but are not limited to Kevlar®, a para-aramid synthetic fiber; Twaron, another para-aramid fiber with roughly the same chemical structure; terephthaloyl chloride (TCI), an aramid fiber closely related to para-aramids; and ultra high molecular weight polyethylene (UHMWPE) such as commercially known Dyneema® and Spectra®. Other suitable materials include polybenzobisoxazole fibers (PBO), glass, quartz, heat resistant aramid fiber products such as Nomex® and Protera® fabrics, fiberizable inorganic ceramic materials such as silicon carbide, carbon, graphite, mullite, aluminum oxide and piezoelectric ceramic materials. Non-limiting examples of suitable fiberizable organic materials include cotton, cellulose, natural rubber, flax, ramie, hemp, sisal and wool. Non-limiting examples of suitable fiberizable organic polymeric materials include those formed from polyamides (such as nylon and aramids), thermoplastic polyesters (such as polyethylene terephthalate and polybutylene terephthalate), acrylics (such as polyacrylonitriles), polyolefins, polyurethanes and vinyl polymers (such as polyvinyl alcohol).
Warp set one and warp set two may be the same denier, although it is preferred that set two be a smaller denier than set one. In a typical woven fabric, the weave is balanced because the weight of the warp yarn and fill yarn are the same; however, by introducing a second set of warp yarn into the fabric, the weave may become slightly unbalanced due to having more warp yarns than fill yarns. This unbalance could be remedied by adding more fill yarns; however this additional fill yarn may increase in the weight of the fabric. One goal in manufacturing high performance fabrics is to keep the fabric weight as low as possible; therefore, a lower weight fabric is desirable. For this reason, it is preferred to use a smaller denier for the second warp set to minimize any additional weight of the resulting fabric. By using a smaller denier for warp set two, this second set can serve to interlock the fill yarns and stabilize the pattern of set one without adding much additional weight to the final fabric itself.
A preferred practical denier range for warp set one is 400-1500 denier. The denier of warp set two depends on the denier of set one, although a preferred practical denier range for set two is 100-400 denier. The fill yarn denier is typically the same as the denier of warp set one, however it may be a different denier if so desired. The fabric weight depends on the denier of set one and set two and the number of yarns per inch. Additionally, the fabric weight of ounces per square yard is based on warp set one, warp set two, and fill yarn construction; typically, the added fabric weight due to the addition of set two preferably will not increase by 20% of the weight of warp set two.
Warp set one determines the weave pattern of the overall fabric, while warp set two interlocks the weave of the fill yarn with warp set one. For example, if the fill yarn and warp set one are woven in a 2/2 basket weave, but warp set two is woven with the fill yarn as plain weave, the overall pattern of the fabric remains 2/2 basket, with the plain weave of set two interrupting the 2/2 basket weave and interlocking the basket pattern. Warp set two is preferably woven into the fabric as a plain weave, although it may be any other desired weave useful for a particular application. Plain weave is preferred for set two due to the over-under-over-under pattern that results in more interlocking of the fill yarn, and a plain weave can typically be cut without unraveling or loss of construction.
Although specific fibers, combinations of fibers, weave patterns, combinations of weave patterns, and specific denier ranges, etc. are discussed herein, it is to be understood that these examples do not limit the present invention to just the described embodiments. It is noted that any person skilled in the art of high performance fabrics would know what types of fibers, weaves, weights, deniers, etc. may be suitable for a particular product and would be capable of making the appropriate substitutions and combinations thereof.
These calculated factors shown in
Yarn diameter inch=1.86×103×(Tex/Density)0.5 Aramid density=1.44 g/cm3
Tex=yarn linear density in gm/1000 m
Warp cover (Kw)=ends/inch×(1/warp diameter (measured in inches))
Fill cover (Kf)=picks/inch×(1/fill diameter (measured in inches))
Fabric cover factor=Kw+Kf−(Kw×Kf)
Fabric tightness factor=cover factor/weave factor
The following tables show the results of ballistic testing of a fabric of the present invention. These tests were performed according to the testing specifications for the National Institute of Justice (NIJ) Standard-0101.06. This standard and other detailed technical information can be found in the NIJ Standard-0101.06, Ballistic Resistance of Body Armor (July 2008) which specifies the minimum performance requirements that equipment must meet to satisfy the requirements of criminal justice agencies and the methods that shall be used to test such performance; this document is herein incorporated by reference in its entirety.
Table 1 shows ballistic performance test results from certified test labs. Fabric “A” and fabric “B” are both a 2/2 twill weave of the present invention (comprising a warp set 1 and warp set 2, described herein) tested against a conventional aramid ballistic fabric (comprising only one warp set). Fabric “A” and “B” are a 0.76 psf panel (corner stitched), and the conventional fabric is a 0.77 psf panel. Tests are performed according to the NIJ Standard-0101.06 for level type II and IIIA, and the V50 performance in both greige and water repellant treated fabric is compared. Fabric A of the present invention shows an improvement in V50 values due to the structure of Fabric A, which consists of warp set 1 and warp set 2, as described herein. This inclusion of warp set 2 not only increases the stability and handleablility of Fabric A, but also reduces the number of fabric plies needed in a pack as compared to conventional ballistic fabric. Typically, water repellent treatment reduces the ballistic performance; however, the V50 shown for water repellant-treated fabric “A” remains superior to that of the conventional fabric.
Table 2 shows hybrid pack ballistic performance as tested in certified test labs. Ballistic testing of these packages is carried out according to NIJ Standard-0101.06, V0 level IIIA protocol, and the backface signature (BFS) is measured. The maximum allowable BFS for law enforcement applications is 44 mm. Fabric “A” is a 2/2 twill of the present invention (comprising a warp set 1 and warp set 2, as described herein) tested in a hybrid design with two different unidirectional fiber-based composite laminate products (UD-1 and UD-2) at areal density of 1.26 psf and 1.248 psf respectively. In this hybrid design, Fabric “A” is 40% fabric weight of total pack weight, and the UD products consist of 60% fabric weight of the total pack weight. Fabric “A” shows a good back face signature (BFS) due to observed high engagement of bullets with fabric. Results are shown in table 2, with 44 mm being the maximum allowable BFS. The projectile stopped within the fabric plies, meaning the fabric successfully “engaged” the bullet. This testing demonstrates the fabric performance for law enforcement applications.
The present invention as described hereinafter may be embodied in many different forms and should not be construed as limited to the embodiments set forth. Rather, these embodiments are provided so that this disclosure will be operative, enabling, and complete. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention. One skilled in the art is capable of knowing, for example, which weave patterns, yarn materials, and deniers are preferred for specific high performance fabric uses, composites, etc., as well as what types of substitutions may be appropriate or suitable. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present invention.
Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Unless otherwise expressly defined herein, such terms are intended to be given their broad ordinary and customary meaning not inconsistent with that applicable in the relevant industry and without restriction to any specific embodiment hereinafter described. As used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one”, “single”, or similar language is used. When used herein to join a list of items, the term “or” denotes at least one of the items, but does not exclude a plurality of items of the list.
For exemplary methods or processes of the invention, the sequence and/or arrangement of steps described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be described as being in a sequence or temporal arrangement, the steps of any such processes or methods are not limited to being carried out in any particular sequence or arrangement, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and arrangements while still falling within the scope of the present invention.
Number | Name | Date | Kind |
---|---|---|---|
3252484 | Meyer | May 1966 | A |
3965943 | Goff, Jr. | Jun 1976 | A |
5187003 | Chitrangad | Feb 1993 | A |
5429686 | Chiu | Jul 1995 | A |
6000442 | Busgen | Dec 1999 | A |
6315007 | Mohamed | Nov 2001 | B1 |
6475936 | Chiou | Nov 2002 | B1 |
6854488 | Hay | Feb 2005 | B2 |
7270152 | Ueda | Sep 2007 | B2 |
8141595 | Quigley | Mar 2012 | B2 |
8293665 | Hartert | Oct 2012 | B2 |
20020098759 | Salway | Jul 2002 | A1 |
20080081528 | Carter | Apr 2008 | A1 |
20100124862 | Smith | May 2010 | A1 |
20110183562 | Carter | Jul 2011 | A1 |
20120235433 | Powers | Sep 2012 | A1 |
20140206248 | Vito | Jul 2014 | A1 |
Number | Date | Country |
---|---|---|
2458048 | May 2012 | EP |
Number | Date | Country | |
---|---|---|---|
20160298271 A1 | Oct 2016 | US |
Number | Date | Country | |
---|---|---|---|
62143856 | Apr 2015 | US |