Patent Application
20160237594
This disclosure relates to flame resistant fiber blends, and to flame resistant yarns, flame resistant fabrics, and flame resistant garments and apparel formed of such flame resistant fiber blends, including safety garments and apparel.
Individuals working in environments where there is a risk of flash fire need to wear flame resistant protective apparel. Example occupations include, but are not limited to, petrochemical and gas workers, industrial workers, and fire service personnel who seek to wear flame resistant apparel underneath their turnout gear or as a stand-alone garment for use in applications outside structural firefighting.
Individuals working near energized electrical equipment are exposed to potential risk from electric arc flash hazards that can occur from an arc flash event. Electrical arcs are formed in air when potential difference (i.e., voltage) between two electrodes causes atoms in the air to ionize and become able to conduct electricity.
In general, this disclosure relates to flame resistant fiber blends, and to flame resistant yarns and flame resistant fabrics formed of such flame resistant fiber blends, and to flame resistant garments and apparel, e.g. safety apparel and garments formed thereof.
In one aspect of the disclosure, a flame resistant fiber blend comprises: a plurality of modacrylic flame resistant fibers comprising a first weight percentage of the fiber blend; a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second percentage of the fiber blend, wherein the second weight percentage is greater than the first percentage; and a plurality of second flame resistant fibers comprising a third weight percentage of the fiber blend.
Preferred implementations of this aspect of the disclosure may include one or more of the following additional features. The flame resistant fiber blend comprises: 20 wt % to 45 wt % of modacrylic flame resistant fibers; 40 wt % to 75 wt % of non-flame resistant hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers. The non-flame resistant hydrophilic/absorbent fibers are selected from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. The second flame resistant fibers comprise p-aramid fibers. The first weight percentage is between about 20 wt % and about 45 wt %, and the second weight percentage is between about 40 wt % and about 75 wt %. The third percent is between about 5% and about 30%.
In another aspect of the disclosure, a flame resistant composite fabric comprises: a first flame resistant fabric layer; a second flame resistant fabric layer; and a barrier layer bonding together the first flame resistant fabric layer and the second flame resistant fabric layer, wherein at least one of the first flame resistant fabric layer and the second flame resistant fabric layer is formed of a fiber blend comprising: a plurality of modacrylic flame resistant fibers comprising a first weight percentage of the fiber blend, a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second weight percentage of the fiber blend, wherein the second weight percentage is greater than the first weight percentage; and a plurality of second flame resistant fibers comprising a third weight percentage of the fiber blend; and the composite layer is capable of withstanding temperature of 500° F. for at least 5 minutes without substantial change in the dimensional integrity of the flame resistant composite fabric.
Preferred implementations of this aspect of the disclosure may include one or more of the following additional features. At least one of the first flame resistant fabric layer and the second flame resistant fabric layer is formed of a fiber blend comprises: 20 wt % to 45 wt % of modacrylic flame resistant fibers; 40 wt % to 75 wt % of hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers. The non-flame-resistant hydrophilic/absorbent fibers are selected from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulosic fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. The second flame resistant fibers comprise p-aramid fibers. The first weight percentage is between about 20 wt % and about 45 wt %, and the second weight percentage is between about 40 wt % and about 75 wt %. The third weight percent is between about 5 wt % and about 30 wt %. The flame resistant composite fabric may be incorporated in a fabric garment. The second (outer) flame resistant fabric layer is a woven layer, knit layer, laminate layer, or combinations thereof.
In another aspect of the disclosure, a flame resistant composite fabric comprises: a first flame resistant fabric layer; a second flame resistant fabric layer; and a barrier layer bonding together the first flame resistant fabric layer and the second flame resistant fabric layer, wherein at least one of the first flame resistant fabric layer and the second flame resistant fabric layer is formed of a fiber blend comprising: a plurality of modacrylic fibers comprising a first weight percentage of the fiber blend, a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second weight percentage of the fiber blend, wherein the second weight percentage is greater than the first weight percentage; and a plurality of second flame resistant fibers comprising a third weight percentage of the fiber blend; and wherein the flame resistant composite fabric offers protection from electric arc flash hazards and/or from flash fire hazards in accordance with one or more of the following Nation Fire Protection Association standards: NFPA 70E (2012 Ed.), NFPA 1975 (2009 Ed.), NFPA 1977 (2011 Ed.), NFPA 1951 (2007 Ed.), and NFPA 2112 (2012 Ed.).
Preferred implementations of this aspect of the disclosure may include one or more of the following additional features. At least one of the first flame resistant fabric layer and the second flame resistant fabric layer is formed of a fiber blend comprising: 20 wt % to 45 wt % of modacrylic fibers; 40 wt % to 75 wt % of hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers. The non-flame-resistant hydrophilic/absorbent fibers are selected from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulosic fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. The second flame resistant fibers comprise p-aramid fibers. The first weight percentage is between about 20 wt % and about 45 wt %, and the second weight percentage is between about 40 wt % and about 75 wt %. The third weight percent is between about 5 wt % and about 30 wt %. The flame resistant composite fabric may be incorporated in a fabric garment. The second flame resistant fabric layer is a woven layer, a knit layer, a laminate layer, or combinations thereof. The flame resistant composite fabric may be incorporated in a fabric garment.
In another aspect of the disclosure, a flame resistant yarn for use in apparel comprises: a plurality of modacrylic flame resistant fibers comprising a first weight percentage of the yarn; a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second percentage of the yarn, wherein the second weight percentage is greater than the first percentage; and a plurality of second flame resistant fibers comprising a third weight percentage of the yarn.
Preferred implementations of this aspect of the disclosure may include one or more of the following additional features. The flame resistant yarn comprises: 20 wt % to 45 wt % of modacrylic fibers; 40 wt % to 75 wt % of hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers. The non-flame-resistant hydrophilic/absorbent fibers are selected from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof.
In still another aspect of the disclosure, flame resistant fabric for use in apparel comprises: a plurality of modacrylic flame resistant fibers comprising a first weight percentage of the fabric; a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second percentage of the fabric, wherein the second weight percentage is greater than the first percentage; and a plurality of second flame resistant fibers comprising a third weight percentage of the fabric.
Preferred implementations of this aspect of the disclosure may include one or more of the following additional features. The flame resistant fabric comprises: 20 wt % to 45 wt % of modacrylic flame resistant fibers; 40 wt % to 75 wt % of hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers. The non-flame-resistant hydrophilic/absorbent fibers are selected from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. The fabric has a char length according to ASTM D6413 of less than 4 inches. The flame resistant fabric stops burning within no more than 2 seconds after removal of an external flame source according to ASTM D6413. The flame resistant fabric has an average arc resistance rating according to ASTM F 1959 of at least 4 calories per tested sample. The flame resistant fabric has an average arc resistance rating according to ASTM F 1959 of at least 1.0 calorie per fabric ounce per square yard. The flame resistant fabric has a heat and thermal shrinkage resistance according to ISO 17493 of less than about 10% shrinkage in both the length and width directions. The flame resistant fabric complies with the requirements of NFPA 2112 (2012 Ed.) for liner fabrics. The flame resistant fabric complies with the requirements of NFPA 1977 (2011 Ed.) for thermal liner fabrics.
In still another aspect of the disclosure, a flame resistant garment comprises: a plurality of modacrylic flame resistant fibers comprising a first weight percentage of the garment; a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second percentage of the garment, wherein the second weight percentage is greater than the first percentage; and a plurality of second flame resistant fibers comprising a third weight percentage of the garment.
Preferred implementations of this aspect of the disclosure may include one or more of the following additional features. The flame resistant garment comprises: 20 wt % to 45 wt % of modacrylic flame resistant fibers; 40 wt % to 75 wt % of hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers. The non-flame-resistant hydrophilic/absorbent fibers are selected from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof.
Implementations of the disclosure can provide one or more of the following advantages.
The flame resistant composite fabrics of the disclosure offer protection against electric arc and/or flash fire hazards.
The flame resistant fabrics of the disclosure have a laminated membrane-film-adhesive structure stabilized by a high level of cross-linking, to reduce thermal shrinking (at 500° F. for 5 minutes).
Alternatively, or in addition, the first and/or second flame resistant fabric layer is a knit or woven fabric where the fiber component(s) will have low shrinkage, e.g. less than about 10% shrinkage in both fabric directions, when exposed to heat (at 500° F. for 5 minutes). Fibers of a few materials such as p-aramid and m-aramid meet this requirement. It will be preferred to use these fibers, or fiber blends, in the stitch yarns of knit fabrics (which controls the dimensional stability when exposed to high heat) or in woven fabrics (warp and fill).
The raised surface of the knit construction (velour, grid, or box pattern) will be made of the same flame resistant fiber blend as the stitch or other flame resistant yarn, e.g. modacrylic fibers, non-flame resistant cellulosic fibers, e.g. cotton fibers, regenerated cellulosic fibers, rayon fibers, etc., and p-aramid fibers, and blends of same, in yarn and fabrics.
Implementations of the disclosure may also provide one or more of the following advantages. A flame resistant fiber blend is provided for use in flame resistant fabrics and flame resistant garments and apparel. The flame resistant fiber blend contains an intimate mixture of modacrylic flame resistant fibers; non-flame-resistant hydrophilic/absorbent fibers, e.g. cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, and combinations thereof; and second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. The amount or weight percentage of each component in the fiber blend is selected to provide the fiber blend with desired properties. For example, the fiber blend is flame resistant and has a high limited oxygen index (LOI). Yarns made from the fiber blend can be used as stitch yarn and/or as loop yarn incorporated in fabrics or garments described in U.S. Pat. No. 6,927,182, the entire disclosure of which is incorporated herein by reference. Fabrics made from the fiber blend can have good integrity when exposed to flame. The fabrics can also endure heavy wearing, e.g., rough abrasion under a military and/or paramilitary body armor, while providing a soft touch to human skin. In addition, the fiber blend can manage water effectively, e.g., by absorbing liquids, such as sweat, from human skin to provide additional comfort or temperature adjustment to the wearer. Selection of the materials also makes the fiber blend cost effective.
Implementations of fiber blends, yarns, and fabrics of the disclosure, at different levels of flame resistant properties, will include relatively higher weight percentage of hydrophilic/absorbent fibers like cellulosic fibers, cotton fibers, regenerated cellulosic fibers, etc., e.g. as compared to the weight percentage of modacrylic fibers. Relatively higher cellulosic fiber content, i.e. higher than modacrylic, will enhance the comfort level of the user, especially during higher levels of physical activity, as well as in high humidity and/or warm ambient conditions. The modacrylic fibers, even at a percentage as low as 20 wt %, in combination with cellulosic fibers at up to 70 or 75 wt % of the fiber blend, will still have sufficiently high LOI, e.g. higher than 28, to be considered as inherent flame resistant (“FR”). In other implementations, the non-flame resistant hydrophilic/absorbent fibers may be replaced, in part or in whole, with flame resistant (FR) cellulosic fibers, e.g. such as Lenzing™ FR treated regenerated cellulosic fibers, or with wool fibers, which by their nature have LOI of 24 to 26.
Implementations of flame resistant fabrics formed of flame resistant fiber blends of this disclosure will have different textile constructions, including, but not limited to, woven, knit, including circular knit and warp knit, non-woven, and combinations thereof, such as in laminates with or without a breathable or other membrane.
Other aspects, features, and advantages of this disclosure are in the description, drawings, and claims.
Like reference symbols in the various drawings indicate like elements.
This disclosure relates to flame resistant fiber blends, and to flame resistant yarns, flame resistant fabrics, e.g. composite fabrics, and flame resistant apparel and other garments, e.g. safety apparel and other garments formed of such fiber blends. For example, a garment having the form of a zippered jacket garment 10 is shown in
The flame resistant fiber blends can include a blend of modacrylic flame resistant fibers, available, e.g., from Kaneka Americas Holding, Inc., of Osaka, Japan (trademarks Protex®C and/or Protex®M) and from Formosa Chemicals & Fibre Corp., of Taipei, Taiwan; non-flame resistant hydrophilic/absorbent fibers, e.g. cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, regenerated cellulose fibers (trademark Tencel®), lyocell regenerated cellulosic fibers, wool fibers, and combinations thereof; and second flame resistant fibers, e.g. para-aramid (p-aramid) fibers and meta-aramid (m-aramid) fibers, both available, e.g., from E.I DuPont de Nemours and Company, Inc., of Wilmington, Del. (trademarks (e.g., Kevlar® and Nomex®, respectively), polyamide-imide fibers (classified in the meta-aramid family), available, e.g., from SwicoFil AG, of Emmenbruecke, Switzerland (trademark Kermel®), polyarylate fibers, PBI (polybenzimidazole) fibers, melamine fibers, available, e.g. from Basofil Fibers, LLC, of Enka, North Caroline, USA (trademark Basofil®); FR rayon fibers, available, e.g., from Lenzing Aktiengesellschaft, of Lenzing, Austria (trademark Lenzing™), FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. Optionally, the fiber blend can also include flame resistant and/or non-flame resistant antistatic fibers. The flame resistant fiber blend can be made into flame resistant yarn, which in turn can be knitted or woven into flame resistant composite fabrics, e.g. for use in apparel. For example, the flame resistant composite fabrics are made into safety garments to provide arc protection and flame resistance.
The disclosure also relates to composite fabrics formed of the fiber blends, which include, e.g., a face fabric (an outer fabric layer) made from a flame resistant (or inherently flame resistant) woven or knit fabric that is permanently bonded with flame resistant chemistry (e.g., adhesive and additive) to an inner fabric (inner fabric layer) made from a flame resistant woven or knit fabric. The resulting composite meets the flame resistant testing requirements for wearer protection from electric arc flash. Through the selection of materials and processes, the resulting composite can also be adapted to provide a wide range of air permeability.
As used herein, “aramid” fibers refers to a polyamide wherein at least 85% of the amide (—COHN—) linkages are attached directly to two aromatic rings. Suitable aramid fibers are described in Man-Made Fibers—Science and Technology, Volume 2, section titled: “Fiber-Forming Aromatic Polyamides”, page 297, W. Black et al., Interscience Publishers, 1968, the entire disclosure of which is incorporated herein by reference. Aramid fibers are also described in U.S. Pat. Nos. 4,172,938; 3,869,429; 3,819,587; 3,673,143; 3,354,127; and 3,094,511, the entire disclosures of all of which are also incorporated herein by reference. P-aramids are those aramids having the amid linkages in the para-position relative to each other, while m-aramids are those aramids having amid linkages in the meta-position relative to each other.
As used herein, “non-flame resistant hydrophilic/absorbent” fibers is used to refer to cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, wood pulp fibers, etc. Hydrophilic/absorbent fibers absorb moisture, and fabric formed of a combination of hydrophilic cellulosic fibers and modacrylic fibers can advantageously exhibit both wicking and moisture transport properties.
As used herein, “flame resistant treated cotton” and “flame resistant (FR) treated cotton blends” such as 88/12, as used herein, refer to cotton/nylon or 100% cotton containing fabrics that have been treated with flame resistant chemistry to impart flame resistance. These fabrics have in effect been “treated” to impart FR performance. The two common approaches to treating such fabrics are to bind phosphorus based chemistry to cellulose via use of an ammoniation chamber or via thermal treatment conducted on a thermosol finishing range. As used herein, a “thermosol finishing range” refers to a heated oven that employs dry heat at temperatures ranging from about 175° C. to 230° C. to perform thermosoling. “Thermosoling” as used herein is a process of chemically treating fabrics in which a chemical is diffused and fixed inside the fibers by means of dry heat.
As used herein, the term “flame resistant fabric” refers to a desired protective layer that has been woven, knitted or otherwise assembled using one or more different types of yarn that are either inherently flame resistant or are treated in fabric form to make them flame resistant. As used herein, the term “flame resistant composite fabric” refers to composite fabric created via bonding two or more layers of flame resistant fabric together without the use of sewing, stitch-bonding, quilting, or other processes that utilize a stitch or interlace yarn to combine two or more fabric layers.
The fiber blend can include, e.g., between about 20 wt % and about 45 wt % of modacrylic fibers. The modacrylic fibers are good flame resistant material, having a high resistance to chemicals and solvents, and a high LOI value, e.g. 32-34. In addition, modacrylic fibers are soft and flexible. These fibers can bend easily and have a relatively softer touch to human skin, e.g. as compared to p-aramid and m-aramid fibers. Modacrylic fibers are also an economical material. Use of modacrylic fibers in the fiber blend (or the yarn or the fabric) can provide the fiber blend with good flame resistance properties at a relatively low cost.
The modacrylic fibers used in the fiber blend can be Protex C, Protex®M, or a combination of the two materials. Protex®C is relatively finer (having a denier of about 1.7) than Protex®-M (having a denier of about 2.2). The selection of Protex®C, Protex®M or their combination can be made based on the desired properties, e.g., being fine, of the yarn to be made from the fiber blend. In some embodiments, the modacrylic fibers used in the fiber blend can include about 10 wt % to about 90 wt % of Protex®C and about 90 wt % to about 10 wt % of Protex®M.
Suitable non-flame resistant natural fibers or regenerated fibers for use in the fiber blend can include cellulosic fibers, cotton fibers, wool fibers, rayon fibers, viscose fibers, modal fibers, rayon fibers, and others, e.g., lyocell or Tencel® regenerated cellulose fibers, e.g. available from Lenzing Aktiengesellschaft, of Lenzing, Austria. In some implementations, the fiber blend can include between about 40 wt % and/or up to about 75 wt % of non-flame resistant hydrophilic/absorbent fibers, selected e.g. from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. Inclusion of these fibers can improve water management capability of the fiber blend without adversely affecting the flame resistance properties of the fiber blend. For example, the fiber blend can remove excessive liquid sweat from human skin, e.g., by wicking the liquid sweat and/or absorbing the liquid sweat from the skin. In some implementations, the natural or regenerated fibers are hydrophilic. The hydrophilicity of the natural fibers can further facilitate the ability of the fiber blend to manage water, e.g., sweat from human skin.
In some implementations, the fiber blend includes at least about 5% by weight (“wt %”), e.g., at least about 7 wt %, and/or up to about 25 wt %, or even up to 30 wt %, e.g., up to about 17 wt %, or 18 wt %, of second flame resistant fibers, e.g. selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. For example, p-aramid fibers are a high strength material and can provide a yarn made out of the fiber blend with strength, e.g., tensile strength as well as abrasion resistant. In addition, the p-aramid fibers can provide fabric integrity when the fabric is exposed to flame. For example, the p-aramid fibers restrict (or inhibit) the fiber blend (in the yarn or in the fabrics) from carbonizing and disintegrating and keeps the fabric integral. Furthermore, the p-aramid fibers can provide toughness to the fabric for use in heavy wear or rough abrasion, e.g., rough abrasion under military or paramilitary body armor. In some implementations, the flame resistant composite fabric used at different portions of apparel has different percentages of the p-aramid fibers (or Kevlar). For example, in a garment to be worn by military or para-military personnel, the garment portions where body armor is located or carried may include a higher percentage, e.g., 10 wt % to 15 wt % of the p-aramid fibers, than portions where no body armor is located or carried, which can include, e.g., 8 wt % to 12 wt % of the p-aramid fibers. In some implementations, multiple layers (e.g., knitted layers) of the fiber blend can be used, e.g., laminated, into the fabrics for use in a garment. As an example, the outermost layer can include a high percentage of the p-aramid fibers to protect the garment made from the laminated fabrics from rough abrasion.
In some implementations, the fiber blend comprises 20 wt % to 45 wt % of modacrylic flame resistant fibers; 40 wt % to 75 wt % of non-flame resistant hydrophilic/absorbent fibers; and 5 wt % to 30 wt % of second flame resistant fibers, as discussed above. Fiber blends having such components (and the yarns or fabric layers containing or made of the fiber blends) can have a low shrinkage, e.g. less than about 10% shrinkage in both fabric directions, when exposed to heat at 500° F. for 5 minutes and low flammability.
In some implementations, the fiber blend includes up to between about 5% and/or up to about 30 wt % of m-aramid fibers, e.g., Nomex®. The m-aramid fibers can provide good thermal, chemical, and radiation resistance, and have good flame resistant properties and low thermal shrinkage, e.g. less than about 10% shrinkage in both fabric directions, when exposed to heat (at a temperature of 500° F. for 5 minutes). For example, the m-aramid fibers, e.g., super flame resistant m-aramid fibers, have a high limiting oxygen index (LOI) of about 37 to about 44. Also, the m-aramid fibers are strong fibers and can provide the fabric made of the fiber blend with a reasonable abrasion resistance. The m-aramid fibers have good strength retention when exposed to heat, as well as good stress-strain property at temperatures above the melting points of other synthetic fibers.
In some implementations, the fiber blend forming at least one of the first flame resistant fabric layer and/or the second flame resistant fabric layer, e.g. both of the first and second flame resistant fabric layers, is formed of an intimate fiber blend comprising: a plurality of modacrylic fibers comprising a first weight-percentage (“wt %”) of the fiber blend; a plurality of non-flame resistant hydrophilic/absorbent fibers comprising a second weight-percentage of the fiber blend, wherein the second weight-percentage is greater than the first weight-percentage; and a plurality of second flame resistant fibers comprising a third weight-percentage of the fiber blend. The non-flame resistant hydrophilic/absorbent fibers are selected, e.g., from among: cellulosic fibers, cotton fibers, regenerated cellulosic fibers, rayon fibers, Tencel® regenerated cellulose fibers, lyocell regenerated cellulosic fibers, wool fibers, viscose fibers, modal fibers, and combinations thereof. The second flame resistant fibers are selected from among p-aramid fibers, m-aramid fibers, polyamide-imide fibers, polyarylate fibers, PBI (polybenzimidazole) fibers, Basofil® melamine fibers, FR rayon fibers, FR cellulosic fibers, FR treated cotton fibers, FR regenerated cellulosic fibers, and combinations thereof. The first weight-percentage is between about 20 wt % and about 45 wt %, and the second percentage is between about 40 wt % and about 75 wt %. The third weight-percent is between about 5 wt % and about 30 wt %.
The fiber blend can also include about 1 wt % to about 5 wt % of antistatic fibers to reduce or eliminate static electricity on the surface of the flame resistant composite fabrics. Suitable antistatic fibers can include carbon fibers or synthetic fibers containing carbon or silver. The antistatic fibers may be flame resistant or non-flame resistant, as desired.
Examples of formulations of intimate fiber blends of the disclosure described above, i.e. comprising modacrylic fibers, non-flame resistant hydrophilic/absorbent cellulosic fibers, and second flame resistant fibers, include, without limitation:
*30% Protex® V Blend (90% modacrylic fibers with 10% polyarylate (aromatic polyethylene) fibers)
**35% Protex® V Blend (84% modacrylic fibers with 16% polyarylate (aromatic polyethylene) fibers)
The fiber blend described above can made into yarns using commonly known methods, such as yarn spinning techniques including ring spinning, core spinning, and air jet spinning, or higher air spinning techniques such as Murata air jet spinning. The yarn can be incorporated in a knit, e.g., circular knit or warp knit, or a woven construction. A circular knit construction can include, for example, single jersey or double knit. The yarn can also be incorporated in a plaited construction that includes terry sinker loop finished double face or single face, plain loop, or pillar terry loop. For example, the terry sinker loop is in a plaited construction or a reverse plated construction. In some implementations, the yarn is used in warp knitting, such as double needle bar knitting (Raschel knitting) or tricot (plain or mesh). In additional to being used as a stitch yarn, the yarn can also be used as a pile yarn (e.g., in a fleece, velour, or high pile). The yarn can be used in a raised surface and/or a stitch. The high pile yarn can be made using double needle bar knitting (Raschel knitting) or cut loop circular knit. For example, the loops of the loop circular knit can be cut on a knitting machine or after the knitting as part of the finishing process. Various knit constructions and woven constructions are described in U.S. Pat. No. 6,927,182, the entire disclosure of which is incorporated herein by reference. The yarn can be used in three-end fleece and in two-end fleece.
A flame resistant composite fabric made of the yarn can include one or more layers, e.g., laminated layers, of the knit or woven constructions. An example of such a flame resistant composite fabric can be the composite fabric 20 of
In some implementations, the flame resistant fiber blend can be rendered hydrophilic for use, e.g., in fabrics adjacent to human skin. A fiber blend is rendered hydrophilic when the fiber blend is made relatively less hydrophobic, e.g. during processing, as compared to the fiber blend before processing. In some implementations, a yarn made from the fiber blend or a fabric made from the yarn can be processed to be hydrophilic (or relatively less hydrophobic than before being processed). Suitable processing methods can include adding to the fiber blend, the yarn, or the fabric a material such as low molecular weight polyester. For example, the low molecular weight polyester can be added in a dye bath that is used to dye the yarn or the fabric. Suitable low molecular weight polyesters are described, e.g., in U.S. Pat. No. 5,312,667, the entire disclosure of which is incorporated herein by reference.
The fiber blend, yarn, or fabric that is rendered hydrophilic can be used as an inner fabric layer of a garment. As a result, transfer of perspiration from the surface of the inner fabric layer to an outer fabric layer is enhanced because liquid moisture can be transported along the surface fibers of the inner fabric by capillary action. In some implementations, the outer layer of the laminate can be made hydrophobic and/or oleophobic by reducing its surface energy, for example, by depositing particles on the surface of the outer layer to resemble a lotus effect.
The flame resistant composite fabric has an air permeability of about 0 ft3/ft2/min to about 200 ft3/ft2/min, tested according to ASTM D-737 under a pressure difference of ½ inch of water across the flame resistant composite fabric. The entire disclosure of ASTM D-737 is incorporated herein by reference. The air permeability of the flame resistant composite fabric can be controlled via the selection of materials used for the first and second flame resistant fabric layers 21, 22, and the flame resistant barrier layer 23.
Referring to
In some cases, the first (inner) flame resistant fabric layer 21 can define one or more raised inner surface regions, i.e. facing towards the wearer, in the form of a pattern, such as grid, box, etc., selected to generate a channeling effect, e.g. as described in U.S. Pat. No. 6,927,182, the entire disclosure of which is incorporated herein by reference.
Referring still to
Other examples of suitable flame resistant fabrics that can be used as the first (inner) flame resistant fabric layer and/or the second flame resistant (outer) fabric layer are described in U.S. Pat. No. 6,828,003, issued Dec. 7, 2004, the entire disclosure of which is incorporated herein by reference.
As mentioned above, the flame resistant barrier layer 23 is positioned between and permanently bonds the first and second flame resistant fabric layers 21, 22. The flame resistant barrier layer 23 includes an adhesive 24 capable of withstanding exposure to a temperature of 500° F. for 5 minutes without changing the integrity of the composite fabric 20 such as by delamination, separation, shrinking, cracking, etc., as described in the ISO 17493 “Clothing and equipment for protection against heat—Test method for convective heat resistance using a hot air circulating oven” test method requirements, the entire disclosure of which is incorporated herein by reference. Suitable adhesives may include adhesives with low shrinkage at high temperatures, cross-linked adhesives, thermosetting adhesives (1, 2, or 3 component). The adhesive 24 may, in one form, be applied by means of transfer coating from release paper at between 0.25 oz/yd2 and 2.5 oz/yd2. In another form, the adhesive may be applied by means of a solvent bath.
The adhesive 24 can be inherently flame resistant, such as a polyvinyl chloride (PVC) based adhesive. Alternatively, or in addition, the adhesive 24 can include one or more chemical additives selected from brominated aromatic chemical (e.g., decabromodiphenyl oxide (DBDPO), penta bromo phenyl, etc.), antimony trioxide, and blends thereof, which result in the creation of a flame resistant composite fabric suitable for protection from electric arc and flash fire hazards. In some embodiments, for example, the flame resistant barrier layer 23 includes a polyurethane-based adhesive with an additive system that consists of a blend of DBDPO and antimony trioxide.
Alternatively, or in addition, the adhesive 24 can include a base polymer (e.g., acrylic, polyurethane, etc.) and a cross-linking agent, such as melamine. A relatively high level of cross-linking agent will turn the thermoplastic polymer binder/adhesive to a very stable chemical that may resemble thermosetting polymer.
Air permeability can be provided and controlled by applying the adhesive 24 as a continuous layer, and then mechanically modifying the layer of adhesive such as by crushing or stretching. For example, referring to
Still referring to
Alternatively, and still referring to
Alternatively, foamed adhesive can be used to provide air permeability. Referring now to
The adhesive 34 can be inherently flame resistant, such as a polyvinyl chloride (PVC) based adhesive. Alternatively, or in additional, the adhesive 34 can include one or more chemical additives selected from brominated aromatic chemical (e.g., decabromodiphenyl oxide (DBDPO), penta bromo phenyl, etc.), antimony trioxide, and blends thereof, which result in the creation of a flame resistant composite fabric suitable for protection from electric arc and flash fire hazards. In some embodiments, for example, the barrier layer 33 consists of a polyurethane-based adhesive that includes flame resistant additives that consist of a blend of DBDPO and antimony trioxide.
Alternatively, or in additional, the adhesive 34 can include a base polymer (e.g., acrylic, polyurethane, etc.) and a cross-linking agent, such as melamine.
The chemical makeup of the adhesive 34 can help to provide a flame resistant composite fabric that is suitable for protection from electric arc and/or flash fire hazards in accordance with one or more of the following National Fire Protection Association (NFPA) standards: NFPA 70E (2009 Ed.), NFPA 1975 (2009 Ed.), NFPA 1977 (2011 Ed.), NFPA 1951 (2007 Ed.), and/or NFPA 2112 (2012 Ed.). Here, the adhesive 34 is applied as foam at between about 0.3 oz/yd2 and 10 oz/yd2. The foam density (mixing air with adhesive) and the amount of adhesive applied are selected depending on the desired air permeability of the flame resistant composite fabric 30. The flame resistant composite fabric 30 is prepared by first applying foam adhesive 34 on one of the opposed surfaces of fabric layers 31 and 32. Once the adhesive is applied, the other fabric layer is placed upon the adhesive in order to produce the flame resistant fabric composite of the disclosure. The flame resistant composite fabric 30 is then mechanically processed by means of a pair of rollers 39, which apply pressure thereto in an amount between about 10 lbs./in.2 and 150 lbs./in.2 in order to produce a composite having a specific level of air permeability.
Air permeability can also be provided by applying the adhesive, e.g., via rotary printing and/or gravure rolling, in a discontinuous pattern, such as in a dot coating pattern.
The adhesive layers 44 can be inherently flame resistant, such as a polyvinyl chloride (PVC) based adhesive. Alternatively, or in addition, the adhesive layers 44 can include one or more chemical additives selected from brominated aromatic chemical (e.g., decabromodiphenyl oxide (DBDPO), penta bromo phenyl, etc.), antimony trioxide, and blends thereof, which result in the creation of a flame resistant composite fabric suitable for protection from electric arc and flash fire hazards. In some embodiments, for example, the adhesive layers 44 consist of a polyurethane based adhesive that includes a flame resistant additive system that includes a blend of DBDPO and antimony trioxide.
Alternatively, or in addition, the adhesive layers 44 can include a base polymer (e.g., acrylic, polyurethane, etc.) and a cross-linking agent, such as melamine.
The adhesive layers 44 may be applied by means of transfer coating from release paper at a thickness of between 0.25 oz/yd2 and 2.5 oz/yd2. The membrane layer 47 can consist of: film, such as full film; breathable membrane; hydrophobic porous membrane; or non-porous hydrophilic membrane with very high water resistance. Examples of suitable membranes are described, e.g., in U.S. patent application Ser. No. 12/368,225, filed Feb. 9, 2009 (U.S. Patent Publication No. 2009-0197491, published Aug. 6, 2009), U.S. patent application Ser. No. 12/494,070, filed Jun. 29, 2009 (U.S. Patent Publication No. 2009-0260126, published Oct. 22, 2009), and U.S. patent application Ser. No. 11/001,893, filed Dec. 1, 2004 (U.S. Patent Publication No. 2005-0097652, published May 12, 2005), the entire disclosure of each of which is incorporated herein by reference. The membrane layer 47 may be applied by means of transfer coating from release paper at a thickness of between 0.0001 in. and 0.010 in., or directly on the fabric surfaces at a thickness of between 0.0003 in. and 0.010 in.
As shown in
The membrane layer 47 can also be made of electrospun membrane with good water resistance and controlled air permeability. The air permeability can be controlled via the fineness of the electrospun fibers, which may be about 100 nm to about 1,000 nm in diameter. The electrospun membrane can have a weight of about 2 g/m2 to about 15 g/m2. Examples of suitable electrospun membranes are described in U.S. patent application Ser. No. 12/354,986, filed Jan. 16, 2009 (U.S. Patent Publication No. 2009-0186548, published Jul. 23, 2009), the entire disclosure of which is incorporated herein by reference.
The various layers can be bonded together as described using one or more of the adhesive application and bonding processes described in U.S. patent application Ser. No. 12/354,986, filed Jan. 16, 2009 (U.S. Patent Publication No. 2009-0186548, published Jul. 23, 2009) and U.S. patent application Ser. No. 12/368,225, filed Feb. 9, 2009 (U.S. Patent Publication No. 2009-0197491, published Aug. 6, 2009), the entire disclosure of each of which is incorporated herein by reference.
The abrasion performance of fabrics is determined in accordance with ASTM D-3884 “Standard Guide for Abrasion Resistance of Textile Fabrics (Rotary Platform, Double Head Method).”
The arc resistance of the composite fabrics of the disclosure is determined in accordance with ASTM F-1959 “Standard Test Method for Determining the Arc Thermal Performance Value of Materials for Clothing,” the entire disclosure of which is incorporated herein by reference. The flame resistant fabric of the disclosure has an arc resistance rating according to ASTM F 1959 of at least 4 calories per tested sample, e.g. at least 1.0 calorie per fabric ounce per square yard.
The grab resistance of fabrics is determined in accordance with ASTM D-5034 “Standard Test Method for Breaking Strength and Elongation of Fabrics (Grab Test).”
The limited oxygen index (LOI) of fabrics, determined in accordance with ASTM G-125-00 “Standard Test Method for Measuring Liquid and Solid Material Fire Limits in Gaseous Oxidants,” measures the minimum concentration of oxygen, expressed as a volume percent, in a mixture of oxygen and nitrogen that will just support flaming combustion of a material initially at room temperature under the conditions of ASTM D2863.
The tear resistance of fabrics is determined in accordance with ASTM D-5587-03 “Standard Test Method for Tearing of Fabrics by Trapezoid Procedure.”
The thermal protection performance of fabrics is determined in accordance with NFPA 2112 (2012 Ed.) “Standard on Flame Resistant Garments for Protection of Industrial Personnel Against Flash Fire.” The fabrics or garments comply with NFPA 1977 (2011 Ed.) “Standard on Protective Clothing and Equipment for Wildland Fire Fighting.”
The char length of the composite fabrics of the disclosure is determined in accordance with ASTM D-6413-99 “Standard Test Method for Flame Resistance of Textiles (Vertical Method),” the entire disclosure of which is incorporated herein by reference.
The term “thermal protective performance” (or “TPP”) relates to the ability of a fabric to provide continuous and reliable protection to a wearer's skin beneath a fabric when the fabric is exposed to a direct flame or radiant heat.
A 6-inch square fabric specimen is suspended horizontally in a holder over two Meker burners and a radiant panel. Weighted sensors placed on top of the fabric (contact) and 6 mm away (spaced) measure the amount of time required for heat penetrating through the fabric to reach a temperature necessary to cause a 2nd degree burn. This time is multiplied by the exposure heat flux to yield a TPP rating. The resulting measurement corresponds to the amount of time that passes until the wearer suffers a 2nd degree burn.
The convective heat resistance of fabrics or garments is tested using a hot air circulating oven according to the conditions of ISO 17493. A 15 inch square specimen that has been washed three times is marked for length and width and suspended in an air-circulating oven at 500° F. for five minutes, and the degree of shrinkage is calculated. For determination of heat resistance, the fabric sample is examined for melting, dripping, separation, or ignition.
The fabric specimen formed into a size 42 regular coverall garment with specific trim and pocketing configuration is placed on an instrumented mannequin dressed in cotton underwear. The mannequin is subjected to overall heat and flame exposure for three seconds. Sensors embedded in the mannequin predict whether a 2nd or 3rd degree burn will occur at that location and a percent body rating is calculated. This is a pass/fail test where the fabrics created via this invention pass the ASTM F 1930 standard test with less than 50% predicted body burn.
The flame resistant composite fabrics made of the fiber blend described previously can have good flame resistant properties. For example, the fabrics can have a char length according to ASTM D6413 of less than 4 inches. The char length of the fabrics is measured in a fabric flammability test according to ASTM D6413, in which a fabric sample is suspended vertically above a fixed external flame placed at the lower edge of the fabric sample. The extent of fabric burning (or charring) measured from the edge of the lower fabric sample is the char length of the fabric sample. The fabrics can stop burning, e.g., self-extinguish, within no more than 2 seconds after removal of the external flame source according to ASTM D6413. The flame resistant fabric of the disclosure has an arc resistance rating of at least 4 calories per tested sample, e.g. at least 1.0 calories per fabric ounce per square yard, tested according to ASTM 1959. The heat and thermal shrinkage resistance of the fabrics tested according to ISO 17493 is less than about 10% shrinkage in both the length and width directions. The fabrics comply with the requirements of NFPA 2112 (2012 Ed.) for fabrics and/or the requirements of NFPA 1977 (2011 Ed.) for thermal fabrics.
See above under “Test Methods.”
A number of implementations of the disclosure have been described. It will be understood, however, that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.
This application is a continuation of U.S. patent application Ser. No. 13/571,929, filed Aug. 10, 2012, now pending, which is a continuation-in-part of International Application No. PCT/US2011/056577, filed Oct. 17, 2011, now in National Phase, which is a continuation-in-part of U.S. patent application Ser. No. 13/045,799, filed Mar. 11, 2011, now abandoned, and this application claims priority from U.S. Provisional Application No. 61/451,352, filed Mar. 10, 2011, now expired. U.S. patent application Ser. No. 13/045,799 claims priority from U.S. Provisional Application No. 61/326,369, filed Apr. 21, 2010, now expired. The entire disclosures of all of these applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61326369 | Apr 2010 | US | |
| 61451352 | Mar 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13571929 | Aug 2012 | US |
| Child | 15136470 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2011/056577 | Oct 2011 | US |
| Child | 13571929 | US | |
| Parent | 13045799 | Mar 2011 | US |
| Child | PCT/US2011/056577 | US |
