CN115244235A - Flame retardant fabrics with increased strength - Google Patents

Abstract

Embodiments relate to flame resistant fabrics formed from a plurality of spun body yarns and rupture bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric. In some embodiments, the rupture prevention body comprises at least two relatively tough yarns, and the relatively tough yarns comprise an aramid spun core and a sheath.

Description

Flame retardant fabrics with increased strength

Cross Reference to Related Applications

This application claims the benefit of U.S. provisional application No. 62/950,193, filed on 12/19/2019, the entire contents of which are incorporated herein by reference.

Technical Field

Embodiments of the present invention relate to flame resistant fabrics formed from a plurality of spun body yarns and a ripstop extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric. In some embodiments, the rupture prevention body comprises at least two relatively tough yarns, and the relatively tough yarns comprise a core and a sheath.

Background

Protective garments are designed to protect the wearer from hazardous environmental conditions that the wearer may encounter. Such garments include those designed to be worn by firefighters and other rescue personnel, industrial and electric workers, and military personnel.

High tenacity flame retardant fabrics have been developed for military and other applications. Examples of such fabrics are disclosed in U.S. patent No. RE42,309, which is incorporated herein by reference in its entirety. One particular fabric currently on the market (sold under the trade name Defender M Ripstop) is a plain weave fabric formed from spun body yarns having a blend of flame retardant rayon, para-aramid and nylon fibers (specifically, 65% flame retardant rayon/25% para-aramid/10% nylon). Of particular concern in fabric design for military applications is fabric durability as defined by tensile (i.e., breaking) strength and tear strength. Ripstop yarns have been incorporated into these woven fabrics to enhance the strength of such fabrics. For example, the Defender M Ripstop fabric comprises a Ripstop formed from two body yarns. More specifically, two body yarns are woven one at a specific interval in both the warp and weft directions. In this way, the fabric is formed entirely of the same yarns, but is constructed in a manner that imparts strength to the fabric.

However, the high concentration of rayon fibers in the fabric can adversely affect the strength of the fabric. More specifically, rayon fibers weaken when exposed to water and moisture. Therefore, the body yarns that function as an anti-burst function are less able to impart strength to the fabric after such exposure. Accordingly, there is a need for fabrics that better maintain their strength properties after exposure to water and moisture while maintaining flame retardancy and cost effectiveness.

Disclosure of Invention

The terms "invention", "present invention" and "present invention" as used in this patent are intended to refer broadly to all subject matter of this patent and the appended patent claims. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the appended patent claims. The embodiments of the invention covered by this patent are defined by the appended claims, not this summary. This summary is a high-level overview of aspects of the invention and introduces some concepts that are further described below in the detailed description. 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.

In some embodiments, the flame resistant fabric has a warp direction and a weft direction. The flame resistant fabric comprises a plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric. The fabric may also include a plurality of rupture prevention bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric. In some embodiments, each rupture prevention body comprises at least two relatively tough yarns, and each relatively tough yarn comprises a core and a sheath. In some embodiments, the core comprises 100% aramid spun yarn and the sheath comprises a sheath fiber blend.

In some embodiments, the flame resistant fabric has a warp direction and a weft direction. The flame resistant fabric comprises a plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric, wherein in some embodiments, the body yarn fiber blend comprises 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber. The fabric may also include a plurality of rupture prevention bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric. In some embodiments, each burst preventer comprises at least two relatively tough yarns formed from a core and a sheath. In some embodiments, the core comprises 100% aramid staple fiber yarn and the sheath comprises a sheath fiber blend comprising 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber. In some embodiments, 5-25 body yarns are inserted between adjacent rupture prevention bodies in at least one of the warp or weft directions.

In some embodiments, the flame resistant fabric has a warp direction and a weft direction and comprises a plurality of spun body yarns provided in both the warp and weft directions of the fabric. In some embodiments, the spun body yarn is formed from a body yarn fiber blend comprising 50-80% FR rayon fiber, 15-40% para-aramid fiber, and 5-20% nylon fiber. The fabric may also include a plurality of rupture prevention bodies extending between at least some of the spun body yarns in both the warp and weft directions of the fabric. In some embodiments, at least some of the plurality of rupture prevention bodies are formed from two relatively tough yarns comprising a core and a sheath. In some embodiments, the core comprises 100% para-aramid staple fiber yarn and the sheath comprises a sheath fiber blend comprising 50-80% FR rayon fiber, 15-40% para-aramid fiber, and 5-20% nylon fiber. In some embodiments, the body yarn fiber blend and the sheath fiber blend are substantially identical, 10-20 body yarns are inserted between adjacent ripstop bodies in the warp and weft directions of the fabric, and the fabric has a weight between 5-7 ounces per square yard, inclusive.

Detailed Description

The subject matter of embodiments of the present invention is described with specificity herein to meet statutory requirements, but the 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 present or future technologies. The description should not be construed as implying any particular order or arrangement among or between various steps or elements unless and except when the order of individual steps or elements is explicitly described.

Flame resistant fabrics formed from a plurality of flame resistant body yarns forming the fabric body and a plurality of relatively tough yarns provided at discrete locations within the fabric body are disclosed to help impart strength to the fabric. Embodiments of the present invention replace the ripstop body yarn with a different yarn that is less susceptible to degradation or weakening when exposed to water and moisture and therefore is able to continue to impart the necessary strength after such exposure.

Embodiments of the fabrics disclosed herein are those that conform to GL-PD-07-12, rev. 9 (R) ((R))Purchase Description: Cloth, Flame Resistant2016, incorporated herein by reference) and MIL-PRF-32635:Cloth, Flame Resistant(2019, incorporated herein by reference) flame retardant, both of which require the fabric to pass many different performance tests, including meeting thermal protection requirements of having a char length of 4 inches (or less) and an after flame of 2 seconds (or less) when measured according to the test method set forth in ASTM D6413-standard test method for flame retardancy of textiles (vertical test) (2015 edition, incorporated herein by reference in its entirety).

To test the char length and after flame, the fabric samples were hung vertically on the flame for 12 seconds. The fabric must self-extinguish within 2 seconds (i.e., it must have an afterflame of 2 seconds or less). After the fabric self-extinguishes, a specified amount of weight is attached to the fabric and the fabric is lifted so that the weight hangs from the fabric. The fabric typically tears along the charred portion of the fabric. The tear length (i.e., char length) must be 4 inches or less when tested in both the machine direction/warp direction and the cross-machine direction/weft direction of the fabric. The flexibility of the fabric samples is usually tested before cleaning (and therefore when the fabric still contains residual and often flammable chemicals from the finishing process) and after a certain number of washes.

The body yarn comprises a spun yarn composed of one or more flame resistant materials. In some embodiments, the body yarns are formed from intrinsic FR staple fibers or staple fibers that have been treated to be flame resistant. Exemplary FR and non-FR materials that can be used to form the body yarn of the present invention include, but are not limited to, aramids (including para-aramids and meta-aramids); polybenzimidazole ("PBI"); polybenzoxazole ("PBO"); modified polyacrylonitrile fibers; poly {2, 6-diimidazo [4,5-b:40; ultra-high molecular weight ("UHMW") polyethylene; UHMW polypropylene; polyvinyl alcohol; polyacrylonitrile; a liquid crystalline polymer; glass; nylon; carbon; silk; a polyamide; a polyester; and natural and synthetic celluloses (e.g., cotton, rayon, acetate, triacetate, and lyocell Fibers, and their flame retardant counterparts FR cotton, FR rayon, FR acetate, FR triacetate, and FR lyocell), TANLON "Fibers (available from shanghai tenlon Fibers limited), wool, melamine (e.g., BASOFIL @, available from BASOFIL Fibers), polyetherimides, polyethersulfones, pre-oxidized acrylic, polyamide-imide Fibers such as KERMEL Fibers, polytetrafluoroethylene, polyvinylchloride, polyetheretherketone, polyetherimide Fibers, polyvinyl chloride Fibers (polychlal), polyimides, polyimide amides, polyolefins, polyacrylates, and any combinations or blends thereof.

Examples of para-aramid materials 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 materials include NOMEX (available from DuPont), CONEX (available from Teijin), and Kermel (available from Kermel). An example of a suitable modacrylic material is a PROTEX ™ material, available from Kaneka Corporation of Osaka, japan. Examples of PIPD materials include M5 (Dupont). An example of a UHMW polyethylene material includes a polymeric material, VECTRAWM (available from Kuraray). Examples of suitable rayon fiber materials are Lenzing's Viscose ™ and Modal ™ chambers, available from Lenzing Fibers Corporation. One example of an FR rayon fiber material is the Lenzing FR system, also available from Lenzing Fibers Corporation. Examples of lyocell materials include TENCEL G100 ™ and TENCEL AlOO @, both available from Lenzing Fibers Corporation.

In some embodiments, the body yarn is a blend of at least rayon, aramid, and nylon fibers, such as 50-80% FR rayon fibers, 15-40% aramid fibers (e.g., para-aramid fibers), and 5-20% nylon fibers. In some embodiments, the body yarn is of the same blend as the body yarn in Defender M Ripstop fabric (specifically 65% FR rayon/25% para-aramid/10% nylon). In other embodiments, the body yarn has a blend of 70% FR rayon, 20% para-aramid, and 10% nylon. Other fibers may be included in the body yarn. Each end of the body yarn may be formed from a single body yarn, or multiple body yarns may be plied or otherwise combined to form an end.

In addition to the body yarns, relatively tough yarns are provided in discrete, crack-resistant locations within the fabric. As known in the art, "tenacity" is a property related to the ability of a material (in this case a yarn) to resist breakage. The term "relatively tough" is used herein to describe a yarn that has a higher tenacity than the remaining yarns of the fabric (i.e., the body yarns).

The relatively tough yarn may be any type of yarn including, but not limited to, spun yarns, filament yarns, stretch broken yarns, and core spun yarns. In some embodiments, the relatively tough yarn is free of filament yarns. Materials that can be used in the relatively tough yarn include, but are not limited to, the same fibers as described above for the body yarn. The relatively tough yarns may comprise any combination of FR/non-FR materials, so long as the overall fabric is flame retardant and/or meets applicable or desired criteria for flame retardant fabrics (e.g., GL-PD-07-12, rev. 9). Each end of the relatively tough yarn may be formed from a single yarn, or multiple yarns may be combined, coupled, or covered (i.e., plied twisted, wound, sheath-core, wrapped, etc.) to form the end.

In some embodiments, the relatively tough yarn comprises aramid (e.g., para-aramid) content to impart the necessary strength to the fabric. For example, in one embodiment, the relatively tough yarn comprises 100% aramid (e.g., para-aramid) spun yarn. While the 100% aramid staple yarn alone can form a relatively tough yarn, in other embodiments it is plied with another yarn to form a relatively tough yarn. For example, in one embodiment, 100% aramid staple yarn is plied with the body yarn to form a yarn of relative hand.

In yet another embodiment, the relatively tough yarn is a spun yarn having a blend of flame resistant staple fibers such as those disclosed above. In a more specific embodiment, the relatively tough yarn is a spun yarn formed from a blend of aramid and FR rayon fibers (e.g., a 50/50 blend).

In yet another embodiment, the relatively tough yarn is a core spun yarn having a core yarn around which a plurality of individual staple fibers are spun to form a fiber sheath around the core yarn. For example, staple fibers may be spun around a core yarn using a Dreher spinning procedure or an air jet spinning process. The core yarn and staple fibers may be one or more of the various materials identified above. In one embodiment, the core yarn is a 100% aramid (e.g., para-aramid) spun yarn. The fiber sheath may be formed from the same fiber blend as the body yarn. In another embodiment, the fibrous sheath is formed from a blend of different fibers, such as a blend of FR rayon and nylon (e.g., a 90/10 blend).

The flame resistant fabrics described herein may comprise body yarns and relatively tough yarns in any combination or orientation. For example, in some examples of the invention, the fabric may be a woven fabric comprising a warp direction and a weft direction. The body yarns are typically provided in both the warp and weft directions. However, the relatively tough yarns may be contained in only the warp direction, only the weft direction, or both the warp and weft directions to form a grid pattern within the fabric. Any desired weave (e.g., plain, twill) or knit (e.g., single, double, plain, interlock) pattern may be used.

The relatively tough yarns may be located in the fabric in any desired ratio relative to the body yarns. The number of relatively tough yarns used for the ripstop, as well as the frequency of ripstops within the fabric, may depend on the desired strength properties of the fabric, and may be the same or different in the warp and/or weft direction and/or between fabrics. Any number of relatively tough yarns greater than one may be used in each ripstop, and the number of relatively tough yarns in each ripstop need not be the same throughout the fabric. By way of example only, two relatively tough yarns, three relatively tough yarns, four relatively tough yarns, etc. may be used for the rupture prevention body. The ripstop may be provided for every 40 body yarns, 35 body yarns, 30 body yarns, 25 body yarns, 20 body yarns, 15 body yarns, 10 body yarns, 5 body yarns, 4 body yarns, 3 body yarns, 2 body yarns, and 1 body yarn in either or both of the warp and weft directions. The frequency of providing the rupture prevention bodies may be the same or different (1) in one direction of the fabric and/or (2) in different directions of the fabric. In some embodiments, at least two relatively tough yarns but less than 4 relatively tough yarns form a ripstop and between 5 and 30 body yarns, inclusive, are provided between adjacent ripstops in one or both directions of the fabric; between 5 and 25 body yarns, inclusive; between 5 and 20 body yarns, inclusive; between 5 and 15 body yarns, inclusive; between 5 and 10 body yarns, inclusive; between 10-30 body yarns, inclusive; between 10-25 body yarns, inclusive; between 10-20 body yarns, inclusive; and between 10 and 15 body yarns, inclusive.

In some embodiments, the fabrics disclosed herein have an open area of 2 to 12 ounces per square yard ("osy"), inclusive; 3-10 osy, inclusive; 3-9 osy, inclusive; 3-8.5 osy, inclusive; 4-8 osy, inclusive; 4-7.5 osy, inclusive; 4-7 osy, inclusive; 5-7 osy, inclusive; 5.5-7 osy, inclusive; or 6-7 osy, inclusive. In some embodiments, the fabric has a weight of 6 to 7 osy, inclusive, and/or less than or equal to 7 osy and/or less than or equal to 6.5 osy.

Specific non-limiting embodiments of the invention are as follows:

fabric 1 ("IF 1") of the present invention:6.5 An osy woven fabric formed from: (1) A spun body yarn having a fiber blend of 70% FR rayon/20% para-aramid/10% nylon, and (2) a relatively tough yarn that is a core spun yarn having a single 30 cotton count (english) 100% para-aramid spun core yarn and a fiber sheath of 70% FR rayon/20% para-aramid/10% nylon. Providing the body yarn and the relatively tough yarn in both the warp and fill directions, the ratio of body yarn to relatively tough yarn in the warp direction being 19 and the ratio of body yarn to relatively tough yarn in the fill direction being 10, means that the ripstop of two relatively tough yarns follows 19 body yarns in the repeat pattern across the warp direction and 10 body yarns in the repeat pattern across the fill direction. The warp and weft densities were 69 ends/inch and 59 picks/inch, respectively.

Fabric 2 ("IF 2") of the present invention:6.5 An osy woven fabric formed from: (1) A spun body yarn having a fiber blend of 70% FR rayon/20% para-aramid/10% nylon, and (2) a relatively tough yarn that is a core yarn having a single 30 cotton count (english) 100% para-aramid spun core yarn and a fiber sheath of 90% FR rayon/10% nylon. The body yarns and the relatively tough yarns are provided in both the warp and fill directions, with a ratio of body yarns to relatively tough yarns of 19 in the warp direction and a ratio of body yarns to relatively tough yarns of 10 in the fill direction (as described above for fabric 1 of the present invention). The warp and weft densities were 69 ends/inch and 59 picks/inch, respectively.

Fabric 3 ("IF 3") of the present invention:6.5 An osy woven fabric formed from: (1) A spun body yarn having a fiber blend of 65% FR rayon/25% para-aramid/10% nylon, and (2) a relatively tough yarn that is a core yarn having a single 30 cotton count (english) 100% para-aramid spun core yarn and a fiber sheath of 65% FR rayon/25% para-aramid/10% nylon. The body yarns are provided only in the warp direction. Both body yarns and relatively tough yarns are provided in the fill direction, with a body yarn to relatively tough yarn ratio of 10 in the fill direction, which means that two crack preventers of relatively tough yarns follow 10 body yarns in the repeat pattern across the fill direction. The warp and weft densities were 69 ends/inch and 59 picks/inch, respectively.

The fabrics 1 to 3 of the present invention were tested for tensile and tear strength according to GL-PD-07-12, rev. 9, and compared to Defender M Ripstop fabrics described above. Tensile strength is the force required to break a fabric under load and is measured according to ASTM D5034-09: standard test methods for breaking strength and elongation (Grab test) for textile fabrics (2013 version, incorporated herein by reference). According to this method, the specimen is mounted centrally in the clamp of the stretcher and force is applied until the specimen breaks. Values for breaking force and elongation of the test specimen are obtained from machine scales, dials, auto-recording charts or a computer connected to the testing machine. Results are reported in pounds force (lbf).

Tear strength is a measure of the amount of force required to propagate a tear in a fabric after the tear has started. Tear strength of the fabric was measured according to ASTM D1424-09 (standard test method for tear strength of fabric by drop weight (Elmendorf type) (2013 version), incorporated herein by reference) and the results are reported in pounds force (lbf).

Slits of a specified size were cut in fabric samples of specified size according to ASTM D1424-09. A clamp is positioned on the fabric sample on each side of the slot to support the fabric sample. A weighted pendulum is released and rocked downward to apply a force to the fabric sample. The amount of force required to propagate a tear present in the fabric is measured and represents the tear strength of the fabric.

The test results are reflected in table 1.

TABLE 1

* These requirements are the same for MIL-PRF-32635.

As demonstrated in Table 1, the fabrics 1-3 of the present invention both met the type III requirements of GL-PD-07-12, rev. 9 in terms of tensile and tear strength, and exceeded the tensile and tear strength of Defender M Ripstop control fabrics both wet and dry.

Embodiments of the fabrics disclosed herein may be used by themselves or in combination with other fabrics in the construction of various protective garments and are not limited to use in military applications.

Examples

The following provides a collection of exemplary embodiments, including at least some explicitly enumerated as "embodiments," which provide additional description of various example types in accordance with the concepts described herein. These examples are not meant to be mutually exclusive, exhaustive, or limiting; and the invention is not limited to these illustrative examples but includes all possible modifications and variations within the scope of the issued claims and their equivalents.

Example 1. A flame resistant fabric having a warp direction and a weft direction, the fabric comprising a plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric, and a plurality of ripstop bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric, wherein each ripstop body comprises at least two relatively tough yarns, and wherein each relatively tough yarn comprises a core and a sheath, wherein the core comprises 100% aramid staple fiber yarns, and the sheath comprises a sheath fiber blend.

The flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the core comprises 100% para-aramid spun yarns.

The flame resistant fabric of any one of the preceding or subsequent embodiments or combinations of embodiments, wherein the sheath fiber blend comprises FR rayon fiber, aramid fiber, and nylon fiber.

Embodiment 4 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the sheath fiber blend comprises 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber.

Embodiment 5 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the aramid fiber is a para-aramid fiber.

Embodiment 6 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the body yarn fiber blend and the sheath fiber blend are the same.

The flame resistant fabric of any one of embodiment 7, the preceding or subsequent embodiment or combination of embodiments, wherein the body yarn fiber blend and the sheath fiber blend each comprise 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber.

Embodiment 8 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the body yarn fiber blend and the sheath fiber blend are the same.

Embodiment 9 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein 5-25 spun body yarns are inserted between adjacent ripstop bodies in at least one of the warp or weft directions.

Embodiment 10 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein 10-20 body yarns are inserted between adjacent rupture guards in at least one of the warp or weft directions.

Embodiment 11 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the plurality of ripstop extends between at least some of the spun body yarns in both the warp and weft directions of the fabric.

Embodiment 12 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the fabric comprises a weight of between 5 and 7 ounces per square yard, inclusive.

The flame resistant fabric of any one of the preceding or subsequent embodiments or combinations of embodiments, wherein the flame resistant fabric is free of filament yarns.

Example 14. A flame resistant fabric having a warp direction and a weft direction, the fabric comprising a plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric, wherein the body yarn fiber blend comprises 50-80% FR rayon fibers, 15-40% aramid fibers, and 5-20% nylon fibers, and a plurality of ripstop bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric, wherein each ripstop body comprises at least two relatively tough yarns, and wherein each relatively tough yarn comprises a core and a sheath, wherein the core comprises 100% aramid staple fiber yarns and the sheath comprises a sheath fiber blend comprising 50-80% FR rayon fibers, 15-40% aramid fibers, and 5-20% nylon fibers, and wherein 5-25 body yarns are inserted between adjacent ripstop bodies in at least one of the warp or weft directions.

The flame resistant fabric of any one of the preceding or subsequent embodiments or combinations of embodiments, wherein the core comprises 100% para-aramid spun yarns.

The flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the 15-40% aramid fibers in the body yarn fiber blend and the sheath fiber blend comprise 15-40% para-aramid fibers.

Embodiment 17 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the body yarn fiber blend and the sheath fiber blend are the same.

Embodiment 18 the flame resistant fabric of any of the preceding or subsequent embodiments or combinations of embodiments, wherein the plurality of antifracture bodies extend between at least some of the spun body yarns in both the warp and weft directions of the fabric.

The flame resistant fabric of embodiment 19 any of the preceding or subsequent embodiments or combinations of embodiments, wherein the fabric comprises a weight of between 5 and 7 ounces per square yard, inclusive.

An flame resistant fabric having a warp direction and a weft direction, the fabric comprising a plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp direction and the weft direction of the fabric, wherein the body yarn fiber blend comprises 50-80% FR rayon fibers, 15-40% para-aramid fibers, and 5-20% nylon fibers, and a plurality of ripstop extending between at least some of the spun body yarns in both the warp direction and the weft direction of the fabric, wherein at least some of the plurality of ripstops are comprised of two relatively tough yarns, and wherein each relatively tough yarn comprises a core and a sheath, wherein the core comprises 100% para-aramid staple fibers, and the sheath comprises a sheath fiber blend comprising 50-80% FR rayon fibers, 15-40% para-aramid fibers, and 5-20% nylon fibers, wherein the body yarn fiber blend and the sheath fiber blend are substantially the same blend, wherein the body yarn blend and the sheath fiber blend are inserted between the warp direction and weft direction of the fabric at a weight of between adjacent ends of the fabric and wherein the ripstop comprises 5-20% nylon fibers, and wherein the weight of the fabric comprises between adjacent ends per ounce fibers.

Different arrangements of the components described above are possible, as well as components and steps not shown or described. Similarly, some features and subcombinations are of utility and may be employed without reference to other features and subcombinations. Embodiments of the present invention have been described for illustrative, but not restrictive, purposes, and alternative embodiments will become apparent to the reader of this patent. Accordingly, the present invention is not limited to the embodiments described above or illustrated in the drawings, and various embodiments and modifications may be made without departing from the scope of the present invention.

Claims (20)

1. A flame resistant fabric having a warp direction and a weft direction, the fabric comprising:

(a) A plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric; and

(b) A plurality of rupture prevention bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric, wherein each rupture prevention body comprises at least two relatively tough yarns, and wherein each relatively tough yarn comprises a core and a sheath, wherein the core comprises 100% aramid staple yarn and the sheath comprises a sheath fiber blend.

2. The flame resistant fabric of claim 1, wherein the core comprises 100% para-aramid spun yarn.

3. The flame resistant fabric of claim 1, wherein the sheath fiber blend comprises FR rayon fiber, aramid fiber, and nylon fiber.

4. The flame resistant fabric of claim 3, wherein the sheath fiber blend comprises 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber.

5. The flame resistant fabric of claim 3, wherein the aramid fiber is a para-aramid fiber.

6. The flame resistant fabric of claim 1, wherein the body yarn fiber blend and the sheath fiber blend are the same.

7. The flame resistant fabric of claim 1, wherein the body yarn fiber blend and the sheath fiber blend each comprise 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber.

8. The flame resistant fabric of claim 7, wherein the body yarn fiber blend and the sheath fiber blend are the same.

9. The flame resistant fabric of claim 1, wherein 5-25 spun body yarns are inserted between adjacent ripstop bodies in at least one of the warp or weft directions.

10. The flame resistant fabric of claim 9, wherein 10-20 body yarns are inserted between adjacent rupture prevention bodies in at least one of the warp or weft directions.

11. The flame resistant fabric of claim 1, wherein the plurality of ripstop bodies extend between at least some of the spun body yarns in both the warp and weft directions of the fabric.

12. The flame resistant fabric of claim 1, wherein the fabric comprises a weight between 5-7 ounces per square yard, inclusive.

13. The flame resistant fabric of claim 1, wherein the flame resistant fabric is free of filament yarns.

14. A flame resistant fabric having a warp direction and a weft direction, the fabric comprising:

(a) A plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric, wherein the body yarn fiber blend comprises 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber; and

(b) A plurality of ripstop bodies extending between at least some of the spun body yarns in at least one of the warp or weft directions of the fabric, wherein each ripstop body comprises at least two relatively tough yarns, and wherein each relatively tough yarn comprises a core and a sheath, wherein the core comprises 100% aramid staple fiber yarn and the sheath comprises a sheath fiber blend comprising 50-80% FR rayon fiber, 15-40% aramid fiber, and 5-20% nylon fiber,

wherein 5-25 body yarns are inserted between adjacent rupture prevention bodies in at least one of the warp or weft directions.

15. The flame resistant fabric of claim 14, wherein the core comprises 100% para-aramid spun yarn.

16. The flame resistant fabric of claim 14, wherein the 15-40% aramid fibers in the body yarn fiber blend and the sheath fiber blend comprise 15-40% para-aramid fibers.

17. The flame resistant fabric of claim 14, wherein the body yarn fiber blend and the sheath fiber blend are the same.

18. The flame resistant fabric of claim 14, wherein the plurality of ripstop bodies extend between at least some of the spun body yarns in both the warp and weft directions of the fabric.

19. The flame resistant fabric of claim 14, wherein the fabric comprises a weight between 5-7 ounces per square yard, inclusive.

20. A flame resistant fabric having a warp direction and a weft direction, the fabric comprising:

(a) A plurality of spun body yarns each formed from a body yarn fiber blend and provided in both the warp and weft directions of the fabric, wherein the body yarn fiber blend comprises 50-80% FR rayon fiber, 15-40% para-aramid fiber, and 5-20% nylon fiber; and

(b) A plurality of ripstop bodies extending between at least some of the spun body yarns in both the warp and weft directions of the fabric, wherein at least some of the plurality of ripstop bodies consist of two relatively tough yarns, and wherein each relatively tough yarn comprises a core and a sheath, wherein the core comprises 100% para-aramid staple fiber yarn and the sheath comprises a sheath fiber blend comprising 50-80% FR rayon fiber, 15-40% para-aramid fiber, and 5-20% nylon fiber,

wherein:

-the body yarn fiber blend and the sheath fiber blend are substantially identical;

-10-20 body yarns are inserted between adjacent ripstop bodies in the warp and weft direction of the fabric; and

-the fabric comprises a weight between 5-7 ounces per square yard, inclusive.