Patent Application
20180313006
Embodiments of the present invention relate to flame resistant fabrics for inclusion into protective garments for military and electrical applications.
Protective garments are designed to protect the wearer from hazardous environmental conditions the wearer might encounter. Such garments include those designed to be worn by military personnel, as well as firefighters and other rescue personnel and industrial and electrical workers.
Standards have been promulgated that govern the performance of such garments (or constituent fabrics of such garments) to ensure that the garments sufficiently protect the wearer in hazardous situations.
GL-PD-07-12, Rev. 8 (Purchase Description: Cloth, Flame Resistant, Nov. 26, 2014, incorporated herein by reference) and MIL-PRF-EFRCE (Purchase Description: Uniform, Enhanced Flame Resistant Combat Ensemble (EFRCE) Blouse and Trouser, September 2015, incorporated herein by reference) are military purchase descriptions that set forth the performance requirements for fabrics used in flame resistant garments for the army (GL-PD-07-12) and marines (MIL-PRF-EFRCE).
Both purchase descriptions (GL-PD-07-12 and MIL-PRF-EFRCE) include color requirements for military fabrics. More specifically, both address the color shades and camouflage patterns to which the fabrics must be colored, depending on the environment in which the uniforms are intended to be worn. GL-PD-07-12, section 3.6.1; MIL-PRF-EFRCE, sections 3.3.2 and 3.3.4. GL-PD-07-12 identifies the following three camouflage patterns:
Both purchase descriptions set forth colorfastness requirements for fabrics bearing each of the different colors shades and patterns to ensure that the fabrics retain the desired shade of color after laundering and environmental exposures (e.g., light, perspiration, etc.). GL-PD-07-12, section 3.6.3 and Table I (Class 1), Table LA (Class 2), and Table I.B (Class 3); MIL-PRF-EFRCE, section 3.3.5 and Tables I and II.
The purchase descriptions both also contain spectral or near infrared reflectance requirements (“IR requirements”) to help ensure that fabrics complying with such IR requirements provide better camouflage in the infra-red wavelengths of light used by most night-vision devices. GL-PD-07-12, section 3.8 and Table II (Class 1), Table II.A (Class 2), and Table II.B (Class 3); MIL-PRF-EFRCE, section 3.3.7 and Table III (Cloth Type I), Table IV (Cloth Type II), and Table V (Cloth Type V). In other words, the camouflage fabrics blend into the background when viewed using night vision equipment.
Many occupations can potentially expose an individual to electrical arc flash and/or flames. Workers who may be exposed to accidental electric arc flash and/or flames risk serious burn injury unless they are properly protected. To avoid being injured while working in such conditions, these individuals typically wear protective garments constructed of flame resistant materials designed to protect them from electrical arc flash and/or flames. Such protective clothing can include various garments, for example, coveralls, pants, and shirts. Standards have been promulgated that govern the performance of such garments (or constituent layers or parts of such garments) to ensure that the garments sufficiently protect the wearer in hazardous situations. Fabrics from which some such garments are constructed, and consequently the resulting garments as well, are required to pass a variety of safety and/or performance standards, including ASTM F 1506 (Standard Performance Specification for Flame Resistant and Arc Rated Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards, 2015 edition, incorporated herein by reference).
ASTM F 1506 requires that the garments and/or individual layers or parts thereof pass a number of different performance tests. Table 1 of ASTM F 1506 sets forth requirements for woven fabrics, including (among others) strength requirements (e.g., tensile strength, tear strength), colorfastness and laundry shrinkage requirements, and thermal protective requirements (e.g., minimal char length and afterflame requirements). As indicted in Table 1, such requirements may differ depending on the weight of the woven fabric tested. Table 2 of F 1506 sets forth the same property requirements for knitted fabrics.
ASTM F 1506 requires all fabrics (woven or knitted) to have a char length of 6 inches or less and have a two second (or less) afterflame, when measured pursuant to the testing methodology set forth in ASTM D6413 (Standard Test Method for Flame Resistance of Textiles, 2015 edition, incorporated herein by reference). To test for char length and afterflame, a fabric specimen is suspended vertically over a flame for twelve seconds. The fabric must self-extinguish within two seconds (i.e., it must have a 2 second or less afterflame). After the fabric self-extinguishes, a specified amount of weight is attached to the fabric and the fabric lifted so that the weight is suspended from the fabric. The fabric will typically tear along the charred portion of the fabric. The length of the tear (i.e., the char length) must be 6 inches or less when the test is performed in both the machine/warp and cross-machine/fill directions of the fabric. A fabric sample is typically tested for compliance both before it has been washed (and thus when the fabric still contains residual—and often flammable—chemicals from finishing processes) and after a certain number of launderings (e.g., 25 launderings for ASTM F 1506).
The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this patent, all drawings and each claim.
Embodiments of the invention relate to flame resistant fabrics comprising a blend of modacrylic, aliphatic polyamide, and cellulosic fibers. Some embodiments are printed and/or dyed with vat dyes so as to comply with the color requirements (including the color, colorfastness, and IR requirements) set forth in the relevant sections of GL-PD-07-12 and/or MIL-PRF-EFRCE. Some embodiments further include reinforcing yarns that improve the strength of the fabrics. Still other embodiments are flame resistant fabrics for use in electrical applications that comply with some or all of the requirements of ASTM F 1506.
The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.
Some embodiments of the invention include flame resistant fabrics suitable for use in military uniforms. Such embodiments of the fabrics preferably comply with the relevant color requirements (including the color, colorfastness, and IR requirements) set forth in sections 3.6 and 3.8 of GL-PD-07-12 and sections 3.3.2, 3.3.5, and 3.3.7 of MIL-PRF-EFRCE. Moreover, some embodiments of the fabrics are low weight and fast drying, rendering them particularly suitable for hot and hot/humid conditions in that such fabrics manage moisture effectively and dry quickly.
Other embodiments of the invention include flame resistant fabrics that comply with requirements of ASTM F 1506 and thus are suitable for electrical worker applications.
The fabrics may be woven or knitted from a combination of spun yarns containing a blend of different types of fibers. The spun yarns in the fabric may all have the same fiber blend, or the fabric may be formed with spun yarns having different fiber blends.
At least some of the spun yarns are formed of a blend that includes modacrylic fibers. Examples of suitable modacrylic fibers are PROTEX™ fibers available from Kaneka Corporation of Osaka, Japan, SEF™ available from Solutia, PyroTex® available from PyroTex Fibers GmbH, or blends thereof. The modacrylic fibers may constitute 30-80%, inclusive; 35-70%, inclusive; and 40-60%, inclusive, of the fiber blend.
In addition to modacrylic fibers, the blend may also include aliphatic polyamides to increase the fabric strength and abrasion resistance. Nylon or flame resistant (“FR”) nylon, Nylon XF, and Nylon HT are examples of suitable aliphatic polyamides for use in the blend. In some embodiments, aliphatic polyamide fibers (such as nylon and/or FR nylon fibers) constitute 5-50%, inclusive; 10-45%, inclusive; 10-35%, inclusive; 15-30%, inclusive; and 20-30%, inclusive of the fiber blend.
The fiber blend may further include FR or non-FR cellulosic fibers, including, but not limited to, natural and synthetic cellulosic fibers (e.g., cotton, rayon, acetate, triacetate, and lyocell, as well as their flame resistant counterparts FR cotton, FR rayon, FR acetate, FR triacetate, and FR lyocell). Examples of rayon fibers include Viscose™ and Modal™ by Lenzing, available from Lenzing Fibers Corporation. An example of an FR rayon material is Lenzing FR™, also available from Lenzing Fibers Corporation, and VISIL™, available from Sateri. Examples of lyocell fibers include TENCEL™, TENCEL G100™ and TENCEL A100™, all available from Lenzing Fibers Corporation.
In some embodiments, synthetic cellulosic fibers are included in the fiber blend. In one embodiment, FR or non-FR lyocell fibers are included in the blend. In some embodiments, non-FR cellulosic fibers (such as non-FR lyocell fibers) constitute 10-60%, inclusive; 10-55%, inclusive; 10-50%, inclusive; 10-45%, inclusive; 10-40%, inclusive; and 20-40%, inclusive, of the fiber blend. In other embodiments, FR cellulosic fibers (such as FR lyocell fibers) constitute 10-80%, inclusive; 15-75%, inclusive; 15-65%, inclusive; 15-50%, inclusive; 20-40%, inclusive; 10-40%, inclusive; and 15-35%, inclusive, of the fiber blend.
In one specific, non-limiting embodiment, the fiber blend includes a blend of modacrylic, nylon, and cellulosic fibers (e.g., synthetic cellulosic fibers such as lyocell fibers). For example, in one embodiment the spun yarns are formed from a fiber blend having approximately 30-80% modacrylic fibers, approximately 10-60% cellulosic fibers (e.g., synthetic cellulosic), and approximately 5-50% nylon fibers. In yet another embodiment, the spun yarns are formed from a fiber blend having approximately 35-70% modacrylic fibers, approximately 10-50% cellulosic fibers (e.g., synthetic cellulosic), and approximately 10-40% nylon fibers. For example, in still another embodiment the spun yarns are formed from a fiber blend having approximately 40-65% modacrylic fibers, approximately 10-40% cellulosic fibers (e.g., synthetic cellulosic), and approximately 15-40% nylon fibers. The cellulosic fibers (such as lyocell) and nylon fibers used in these blends can be FR or non-FR. The spun yarns of these embodiments are devoid of additional inherently flame resistant fibers, such as aramid fibers. The same types of modacrylic fibers, cellulosic fibers, and nylon fibers need not be used in the blend. Rather, multiple types of each may be blended together.
The cellulosic fibers are provided in the blend to increase the comfort and moisture management of the fabric. In some embodiments, however, it may be desirable (but not required) to use lower levels of cellulosic fibers to help reduce fabric drying time. In some embodiments, the cellulosic fibers constitute less of the fiber blend than the nylon fibers.
Given the flammable nature of non-FR nylon and non-FR synthetic cellulosic fibers (at least as compared to FR fibers), it may be advisable in some embodiments to ensure that the modacrylic fibers constitute more of the fiber blend than each of the non-FR nylon and non-FR lyocell fibers. The modacrylic fibers control and counteract the flammability of the non-FR nylon and non-FR lyocell fibers to prevent them from burning. It may be preferable in some embodiments to ensure that the modacrylic fibers constitute more of the fiber blend that the non-FR nylon and non-FR lyocell fibers combined. In some embodiments, the fiber blend is devoid of other FR fibers typically used in FR fabrics to impart FR properties to the fabrics, such as, but not limited to, aramid fibers such as meta- and para-aramid fibers.
However, in other embodiments other fibers are added to the fiber blend of the spun yarns, including, but not limited to, additional inherently FR fibers and/or non-inherently FR fibers (FR or non-FR). Exemplary suitable FR and non-FR fibers include, but are not limited to, para-aramid fibers, meta-aramid fibers, polybenzoxazole (“PBO”) fibers, polybenzimidazole (“PBI”) fibers, poly{2,6-diimidazo [4,5-40; 50-e]-pyridinylene-1,4(2,5-dihydroxy)phenylene} (“PIPD”) fibers, ultra-high molecular weight (UHMW) polyethylene fibers, UHMW polypropylene fibers, polyvinyl alcohol fibers, polyacrylonitrile (PAN) fibers, liquid crystal polymer fibers (e.g., aromatic polyesters such as VECTRAN), glass fibers, polynosic rayon fibers, carbon fibers, silk fibers, polyamide fibers, polyester fibers, aromatic polyester fibers, TANLON™ fibers (available from Shanghai Tanlon Fiber Company), wool fibers, melamine fibers (such as BASOFIL™, available from Basofil Fibers), polyetherimide fibers, polyethersulf one fibers, pre-oxidized acrylic fibers, polyamide-imide fibers such as KERMEL™, polytetrafluoroethylene fibers, polyvinyl chloride fibers, polyetheretherketone fibers, polyetherimide fibers, polychlal fibers, polyimide fibers, polyamide fibers, polyimideamide fibers, polyolefin fibers, polyacrylate fibers, and any combination or blend thereof. In some embodiments, however, embodiments of the fabrics contemplated herein are devoid of any and/or all of these additional inherently FR fibers and/or non-inherently FR fibers (FR or non-FR).
Examples of para-aramid fibers include KEVLAR™ (available from DuPont), TECHNORA™ (available from Teijin Twaron BV of Arnheim, Netherlands), and TWARON™ (also available from Teijin Twaron BV). Examples of meta-aramid fibers include NOMEX™ (available from DuPont), CONEX™ (available from Teijin), and APYEIL™ (available from Unitika). An example of a polyester fiber is DACRON® (available from Invista™). An example of a PIPD fiber includes M5 (available from Dupont). An example of melamine fibers is BASOFIL™ (available from Basofil Fibers). An example of PAN fibers is Panox® (available from the SGL Group). Examples of UHMW polyethylene materials include Dyneema and Spectra. An example of a liquid crystal polymer material is VECTRAN™ (available from Kuraray).
Moreover, anti-static fibers, anti-microbial fibers, and/or stretch fibers may also be added to the blend.
The spun yarns can be formed in conventional ways well known in the industry. The spun yarns can comprise a single yarn or two or more individual yarns that are twisted, plied, or otherwise combined together.
The spun yarns can subsequently be used to form fabrics in a variety of ways, all well known in the industry. The yarns can be knitted or woven. In one embodiment, the fabric is formed as a plain weave fabric or a twill weave (e.g. 2×1 twill) fabric that comprises a plurality of body yarns. However, it will be appreciated that other configurations could be used including, for instance, a rip-stop weave, sateen weave, etc.
Some embodiments of the present invention incorporate into the fabric reinforcing yarns intended to enhance the strength properties (tensile, tear, etc.) of the fabric. The reinforcing yarns may be spun yarns (such as, but not limited to, those described above), continuous filament yarns, stretch broken yarns, and combinations thereof. The reinforcing yarns may be of any size (i.e., of any cotton count or denier). The reinforcing yarns may be formed from a variety of different materials, including, but not limited to, polyamides (e.g., nylon), high density polyethylene, rayon (FR or non-FR), polyester, aramids (meta-aramid and para-aramid), as well as the other inherently FR fibers and/or non-inherently FR fibers (FR or non-FR) identified above. In some embodiments, the reinforcing yarns are nylon continuous filament yarns.
In some embodiments, the body of the fabric is formed of spun yarns (such as those described above) and the reinforcing yarns are provided in one or both of the machine/warp and cross-machine/fill directions of the fabric. In some embodiments, the reinforcing yarns are provided in both the machine/warp and cross-machine/fill directions of the fabric so as to create a grid-like pattern. The occurrence of the reinforcing yarns may be the same or different in each fabric direction. The reinforcing yarns may be provided in isolation or may be combined, coupled, or covered (i.e., plied, ply twist, wrapped, coresheath, coverspun, etc.) with one or more other yarns (or staple fibers).
The reinforcing yarns may be provided at any frequency within the fabric. For example, a reinforcing yarn may be provided every nth end or pick. The frequency at which reinforcing yarns are used (i.e., the value of “n”) can be the same or different (1) within a direction of the fabric and/or (2) in different directions of the fabric. In some embodiments, the value of “n” can be anywhere between 1-60, inclusive; 1-50, inclusive; 1-40, inclusive; 1-30, inclusive; 1-20, inclusive; 1-10, inclusive; and 1-5, inclusive, such that at least (n-1) ends or picks of body yarns are positioned between the adjacent reinforcing yarns that are separated by body yarns.
Moreover, it is also contemplated that two or more reinforcing yarns may be provided directly adjacent each other (i.e., not separated from each other by body yarns) in one or both directions of the fabric. In other words, at least some occurrences of reinforcing yarns in the fabric may include three reinforcing yarns in a row, four reinforcing yarns in a row, five reinforcing yarns in a row, etc.
The frequency of the occurrence of reinforcing yarns as well as the number of reinforcing yarns provided at each such occurrence may depend on the desired strength properties of the fabric as well as the size of the reinforcing yarns. If a larger sized reinforcing yarn is used, only one such yarn inserted every nth end and/or pick may provide sufficient reinforcement to the fabric. Conversely, if a smaller reinforcement yarn is used, two or more ends or picks of such yarns may be desired where reinforcing yarns are provided in the fabric. In some embodiments, the reinforcing yarns comprise 5-40% of the overall fabric weight.
In some embodiments, the fabrics disclosed herein have a weight between 2-12 ounces per square yard (“osy”), inclusive; 2-10 osy, inclusive; 2-9 osy, inclusive; 2-8 osy, inclusive; 2-7 osy, inclusive; 2-6 osy, inclusive; 2-5 osy, inclusive; 2-4 osy, inclusive; 3-10 osy, inclusive; 3-8 osy, inclusive; 3-6 osy, inclusive; and 3-5 osy, inclusive. In some embodiments, the fabric weight is 4-10 osy, inclusive, and/or is less than or equal to 6 osy.
Desired colors may be imparted in a variety of ways and with a variety of dyes to the fabrics disclosed herein. In some embodiments, the fabrics are printable and/or dyeable with vat dyes to colors and/or patterns that enable the fabrics to comply with various military requirements (including, but not limited to, the color, colorfastness, and IR requirements set forth in sections 3.6 and 3.8 of GL-PD-07-12 and/or sections 3.3.2, 3.3.5, and 3.3.7 of MIL-PRF-EFRCE). For example, such fabrics may be printed in compliance with the such color requirements with vat dyes using known printing techniques. In some embodiments, 100% of the fabric surface is vat dye printed. However, other dyes and dyeing/printing methodologies may be used to color the fabrics. Moreover, some embodiments are the fabrics contemplated herein are dyed/printed in a solid shade devoid of pattern.
Fabrics that may not be—but that are capable of being—dyed and/or printed with vat dyes to colors and/or patterns that comply with the color, colorfastness, and IR requirements set forth in sections 3.6 and 3.8 of GL-PD-07-12 and/or sections 3.3.2, 3.3.5, and 3.3.7 of MIL-PRF-EFRCE are intended to be covered by this patent.
The different patterns specified in each purchase description have different color requirements. The relevant sections of each purchase description that govern the color, colorfastness and IR requirements of a particular pattern is set forth below in Table 1 (for GL-PD-07-12) and Table 2 (for MIL-PRF-EFRCE). It will be obvious to one of skill in the art that a fabric printed with a particular pattern need only satisfy the requirements specified for that particular pattern.
Specific, non-limiting examples of fabrics in accordance with embodiments of the invention are described as follows:
Table 3 sets forth performance data for printed versions of the Modacrylic Blend Ripstop, High Strength Modacrylic Blend Ripstop, and High Strength Modacrylic Blend Twill and compares that data against the applicable requirements of GL-PD-07-12, MIL-PRF-EFRCE, and ASTM F 1506.
All of the testing methodologies referenced throughout this document are hereby incorporated by reference.
With respect to GL-PD-07-12 and MIL-PRF-EFRCE, the Modacrylic Blend Ripstop, High Strength Modacrylic Blend Ripstop, and High Strength Modacrylic Blend Twill surpass almost every required fabric property set forth in the purchase descriptions. For example, these fabrics exceed the tear strength requirements despite being of lighter weights than specified in the purchase descriptions.
Tear strength is a measure of the amount of force required to propagate in a fabric a tear after its initiation. The tear strength of fabrics is measured pursuant to ASTM D1424-09 (Standard Test Method for Tearing Strength of Fabrics by Falling-Pendulum (Elmendorf-Type) Apparatus (2013 edition), incorporated by reference), and the results are reported in pounds force (lbf).
Pursuant to ASTM D1424-09, a slit of a specified size is cut into a fabric sample of a specified size. A clamp positioned on the fabric sample on each side of the slit to support the fabric sample. A weighted pendulum is released and swings down to apply a force to the fabric sample. The amount of force required to propagate the existing tear in the fabric is measured and that amount of force represents the tear strength of the fabric.
The tear strength of fabrics according to embodiments of the invention can be enhanced by inclusion of the reinforcing yarns (such as, e.g., stretch broken and/or filaments yarns, as discussed above) in the fabric. This can be seen, for example, by comparing the tear strength of the Modacrylic Blend Ripstop (devoid of nylon filament yarns) against the stronger High Strength Modacrylic Blend Ripstop and High Strength Modacrylic Blend Twill, which each include nylon filament reinforcing yarns (see Table 3 above).
Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 14 pounds force in one or both of the warp and fill directions. Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 14 pounds force in one or both of the warp and fill directions while being of relatively low weight (6 osy or less). Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 16 pounds force in one or both of the warp and fill directions. Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 16 pounds force in one or both of the warp and fill directions while being of relatively low weight (6 osy or less). Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 19 pounds force in one or both of the warp and fill directions. Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 19 pounds force in one or both of the warp and fill directions while being of relatively low weight (6 osy or less). Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 21 pounds force in one or both of the warp and fill directions. Some embodiments of the fabrics (particularly, but not necessarily, those having reinforcing yarns) have tear strengths greater or equal to 21 pounds force in one or both of the warp and fill directions while being of relatively low weight (6 osy or less).
In some embodiments, inclusion of reinforcing yarns (such as, e.g., stretch broken and/or filaments yarns, as discussed above) in the fabric increases the tear strength of the fabric (in either or both of the warp direction and fill direction) by at least 50%; at least 60%; at least 70%; at least 80%; at least 90%; at least 100%; at least 105%; at least 120%; at least 140%; and/or at least 170%. Such improvement in tear strength can be seen by comparing the tear strength of the fabric formed only with spun body yarns against the tear strength of an otherwise identical fabric that is formed with the same spun body yarns but with reinforcing yarns as well. Such improvement in tear strength can been see, for example, by comparing the tear strength results of the Modacrylic Blend Ripstop against the High Strength Modacrylic Blend Ripstop in Table 3.
The tear strength of the greige fabrics identified in Table 4 were tested. More specifically, four woven fabrics were formed, each with one of the body yarn types identified in Table 4. In other words, the first fabric was formed with body yarns having a 65/25/10 FR rayon/para-aramid/nylon fiber blend. The second fabric was formed with body yarns having a 93/5/2 meta-aramid/para-aramid/anti-static fiber blend. The third fabric was formed with body yarns having a 48/37/15 modacrylic/lyocell/para-aramid fiber blend. The fourth fabric was formed with body yarns having a 55/25/20 modacrylic/nylon/lyocell fiber blend and represents an embodiment of a fabric made pursuant to the present invention.
The fabrics were woven both without reinforcing yarns (i.e., the fabrics only included body yarns) and with identical reinforcing yarns. The break or tensile strength of the body yarns and reinforcing yarns was measured (pursuant to ASTM D5034 (Standard Test Method for Breaking Strength and Elongation of Textile Fabrics (Grab Test) (2013 edition)), and the results were reported in pounds force. Moreover, the tear strength of the fabrics in the fill direction, both with and without reinforcing yarns, was also measured (pursuant to ASTM D1424). The results are graphically represented in Graph 1.
The data demonstrates that the reinforcing yarns were significantly more effective when included in a fabric having weaker body yarns. For example, the first fabric has body yarns that are significantly stronger than those of the fourth fabric. Not surprising, inclusion of the same reinforcing yarns in each of these fabrics increased the overall tear strength of each fabric. However, what is surprising is the efficacy of such reinforcing yarns in fabrics made from weaker yarns. Inclusion of the reinforcing yarns in the fabric with the strongest body yarns (the first fabric) only resulted in a 16% improvement in fabric tear strength. However, inclusion of the same reinforcing yarns in the fabric with the weakest body yarns (the fourth fabric) led to a 57% increase in fabric tear strength. Not only that, the tear strength of the reinforced fabric formed with the weaker yarns actually surpassed the tear strength of the reinforced fabric formed with the strongest yarns.
Embodiments of the fabrics disclosed herein are printable and/or dyeable with vat dyes so as to comply with at least one of the following:
By way only of example, High Strength Modacrylic Blend Twill fabric was vat dye printed with the Class 3, Operational Camouflage Pattern (OCP) pattern specified in GL-PD-07-12, section 3.6.1.3. The colorfastness and near IR reflectance of the fabric was tested and compared against the applicable GL-PD-07-12 requirements for the OCP pattern. Table 5 compares the colorfastness of the High Strength Modacrylic Blend Twill fabric with the OCP pattern against the colorfastness requirements for that pattern (GL-PD-07-12, section 3.6.3 and Table I.B). Table 6 compares the spectral or near IR reflectance of the High Strength Modacrylic Blend Twill fabric with the OCP pattern against the spectral reflectance requirements for that pattern (GL-PD-07-12, section 3.8.3 and Table II.B). The High Strength Modacrylic Blend Twill fabric with the OCP pattern passed all of the applicable colorfastness and near IR reflectance requirements for that pattern.
Fabrics according to some embodiments of the invention are self-extinguishing, exhibit no melt or drip when exposed to a flame or thermal event, and/or have an afterflame of less than or equal to two seconds when tested in accordance with ASTM D6413. While the char lengths of the tested fabrics failed to comply with the requirements of GL-PD-07-12 and MIL-PRF-EFRCE, fabrics according to some embodiments of the invention have a char length of 6 inches or less and of 7 inches or less, when tested pursuant to ASTM D6413.
As evident in Table 3, some embodiments fully comply with the requirements of ASTM F 1506, including exhibiting a char length of 6 inches or less when tested in accordance with ASTM D6413. It is expected that increasing the weight of the fabrics tested would increase the likelihood the fabric complying fully with the requirements of ASTM F 1506.
Embodiments of the flame resistant fabrics disclosed herein can be used to construct the entirety of, or various portions of, a variety of protective garments for use in military applications and/or electrical applications, including, but not limited to, combat uniforms, coveralls, jumpsuits, shirts, jackets, vests, and trousers. Low weight versions (e.g., 6 osy or less) of fabrics disclosed herein may be particularly suitable for inclusion in uniforms for use in hot and hot/humid environments, such as deserts, jungles, and other tropical environments.
Different arrangements of the components described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the invention.
This application claims the benefit of U.S. Provisional Application Ser. No. 62/244,337, filed on Oct. 21, 2015, entitled “Low Cost, Printable Flame Resistant Fabric for Combat Uniforms,” the entirety of which is hereby incorporated by this reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US16/58202 | 10/21/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62244337 | Oct 2015 | US |
