Fabric and article having fire resistance, cut resistance, and elastic recovery and method of making same

Abstract

A flame and cut resistant fabric, and a glove or other article comprising the fabric, the fabric comprising: (a) at least one first yarn comprising at least 50 weight percent of heat resistant polymeric fibers, wherein at least 30 weight percent of the polymeric fibers present in the at least one first yarn are cut resistant heat resistant polymeric fibers having a cut resistance of 500 grams force or more according to ASTM F2992-15; and (b) at least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing staple fibers and a core comprising at least one continuous elastic filament, wherein 60 to 95 weight percent of the at least one second yarn is halogenated self-extinguishing fibers and the halogenated self-extinguishing fibers are in contact with the at least one continuous elastic filament, the second yarn being free or substantially free of inorganic fibers; the fabric having a maximum afterflame time of two seconds or less and a weight loss of 5 weight percent or less when tested according to NFPA-2112-2018.

Description

Background Technology

[0001] 1. Technical Field. This invention relates to yarns and fabrics suitable for protective clothing, which have fire-resistant and close-fitting properties as well as cut-resistant properties.

[0002] Related field description. Twisted yarns and fabrics with cut resistance and elastic recovery, methods of manufacturing them, and their use in protective clothing are disclosed in U.S. Patent No. 6,952,915.

[0003] Yarns comprising modified polyacrylonitrile fibers, para-aramid fibers, and meta-aramid fibers (which can be used to produce fabrics with arc and flame protection properties) are disclosed, for example, in U.S. Patent Nos. 7,065,950 and 7,348,059. These yarns may further comprise, as optional components, 2 to 15 weight percent of abrasion-resistant fibers such as nylon and / or 1 to 5 weight percent of an antistatic component.

[0004] Yarns and fabrics possessing a combination of fire resistance and elastic recovery properties are described, for example, in U.S. Patent Nos. 5,069,957; 5,527,597; and 5,694,981. These existing solutions utilize yarns made by covering the elastic core yarn with a robust, protective fiber outer covering made of fire-resistant fibers. In other words, these references describe protecting the elastic core by structurally shielding it from flames using another fiber in the same yarn.

[0005] As used herein, the terms "structural shielding" and "structural shield" refer to the covering fibers that, when exposed to flame, simply char and remain in place within the yarn, covering any elastic filaments in the core, and thus providing a structural barrier between the flame and the elastic core. As imparted in these patents, these yarns are equipped with a robust, protective fiber outer covering made of fire-resistant fibers that physically protects the elastic core yarn from degradation or melting when exposed to extreme temperatures and fire.

[0006] Unfortunately, in many cases, the fibers that provide sufficient structural shielding for the outer fiber covering are also tend to be stiffer, and therefore fabrics made from such yarns may not be as comfortable as desired. This ultimately results in protective clothing that is not as comfortable as hoped, and it is well known that workers often do not wear their protective gear if it is not comfortable enough, thus putting themselves at risk.

[0007] Furthermore, any solution protecting the elastic core should meet current protective clothing standards. Specifically, the recent NFPA 2112-2018, "Standard on Flame-Resistant Clothing for Protection of Industrial Personnel Against Short-Duration Thermal Exposures from Fire," specifies the minimum design, performance, testing, and certification requirements and test methods for flame-resistant clothing, shrouds, hoods, balaclavas, and gloves used in areas with a risk of short-duration thermal exposure from fire. This standard requires that the fabric used in the clothing have an afterflame time not exceeding 2 seconds. Afterflame time is the time (in seconds, accurate to 0.2 seconds) during which a sample continues to burn after the burner has extinguished the flame.

[0008] The standard imposes even stricter requirements on flame-resistant gloves, stipulating that the material consumed during the flame-resistance test should not exceed 5.0% of the original weight of the sample. In other words, after applying a specified 12-second flame to the sample according to the procedure in the standard, the fabric weight loss should be 5.0% or less.

[0009] Therefore, there is a need for a yarn and / or fabric that has a combination of fire resistance and elastic recovery properties as well as cut resistance, specifically comprising an elastic core yarn, meeting NFPA 2112-2018 standards; and further utilizing fibers with a textile feel to potentially provide more comfortable protective clothing. Summary of the Invention

[0010] This invention relates to a flame-resistant and cut-resistant fabric, and gloves or other articles comprising the fabric, the fabric comprising:

[0011] (a) At least one first yarn comprising at least 50% by weight of heat-resistant polymer fibers based on the total weight of the first yarn, wherein at least 30% by weight of the polymer fibers present in the at least one first yarn are cut-resistant and heat-resistant polymer fibers having a cut resistance of 500 g / L or higher according to ASTM F2992-15; and

[0012] (b) At least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament.

[0013] Based on the total weight of the second yarn, 60 to 95% by weight of the at least one second yarn is halogenated self-extinguishing fiber, and the halogenated self-extinguishing fiber is in contact with the at least one continuous elastic filament, and the second yarn contains no or substantially no inorganic fibers.

[0014] When tested according to NFPA-2112-2018, the fabric has a maximum afterflame time of two seconds or less and a weight loss of 5% or less. Detailed Implementation

[0015] This invention relates to yarns and fabrics suitable for protective clothing, which possess fire-resistant and close-fitting properties, and further provide cut resistance. The unique combination is achieved by combining elastic materials, self-extinguishing fibers, and highly heat-resistant polymer fibers in a manner that provides high fire resistance in the yarn or fabric while limiting fabric consumption during combustion.

[0016] Specifically, the present invention relates to a flame-resistant and cut-resistant fabric, the fabric comprising:

[0017] (a) At least one first yarn comprising at least 50% by weight of heat-resistant polymer fibers based on the total weight of the first yarn, wherein at least 30% by weight of the polymer fibers present in the at least one first yarn are cut-resistant and heat-resistant polymer fibers having a cut resistance of 500 g / L or higher according to ASTM F2992-15; and

[0018] (b) At least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament.

[0019] Based on the total weight of the second yarn, 60 to 95% by weight of the at least one second yarn is halogenated self-extinguishing fiber, and the halogenated self-extinguishing fiber is in contact with the at least one continuous elastic filament, and the second yarn contains no or substantially no inorganic fibers.

[0020] When tested according to NFPA-2112-2018, the fabric has a maximum afterflame time of two seconds or less and a weight loss of 5% or less.

[0021] "Flame-resistant and cut-resistant fabric" means a knitted or woven fabric that is both "flame-resistant" and "cut-resistant". For the fabric, the descriptive term "flame-resistant" means that, when tested according to ASTM 6143-15, the char length of the fabric is equal to or less than 4 inches (100 mm). "Cut-resistant fabric" means that the fabric has at least a minimum level of cut resistance, and typically, according to ASTM F2992-15, the cut resistance of a cut-resistant fabric is at least 200 g / m². In some preferred embodiments, the fibers and yarns described herein can provide a flame-resistant and cut-resistant fabric with a cut resistance of at least 500 g / m² according to ASTM F2992-15. However, it should be understood that in some other embodiments, other fibers or yarns that do not necessarily provide cut resistance but can provide other desired qualities to the fabric may be incorporated into the fabric, provided that the flammability requirements described herein for what is considered a "flame-resistant" fabric are met and the fabric maintains a minimum cut resistance of at least 200 g / m² according to ASTM F2992-15.

[0022] Flame-retardant fabrics provide thermal protection from thermal events, while cut-resistant fabrics provide mechanical protection from objects such as knives and sharp edges. In addition to being flame-retardant, this fabric exhibits an afterflame time of two seconds or less and a weight loss of 5% or less when tested according to NFPA-2112-2018.

[0023] Furthermore, comfort and good fit and flexibility are generally important or desirable for any product made from such fabrics (such as protective gloves). "Good fit and flexibility" means, for example, that the gloves conform well to the shape of the wearer's hand, and that people can pick up and manipulate small objects while wearing the gloves. Flame-resistant and cut-resistant fabrics as described herein are highly flame-resistant and cut-resistant, while also providing a soft, flexible, and close-fitting garment. Protective clothing made from such fabrics is very comfortable and effectively protects against a variety of threats.

[0024] The flame-retardant and cut-resistant fabric is made of at least one first yarn and at least one second yarn, wherein the at least one first yarn provides heat-resistant polymer fibers, and the at least one second yarn provides at least one continuous elastic filament covered by halogenated self-extinguishing fibers in contact with the at least one continuous elastic filament. The fabric is then manufactured using the at least one first yarn and the at least one second yarn.

[0025] In some embodiments, the at least one first yarn and the at least one second yarn are twisted together to form a ply twisted yarn. In some embodiments, the ply twisted yarn consists of only one type of first yarn and only one type of second yarn. In other embodiments, the ply twisted yarn consists of only one type of first yarn and multiple types of second yarn; and in other embodiments, the ply twisted yarn consists of multiple types of first yarn and only one type of second yarn. Similarly, in some embodiments, the ply twisted yarn consists of multiple types of first yarn and multiple types of second yarn. Finally, in some embodiments, the ply twisted yarn includes at least one first yarn and at least one second yarn; other yarns made of any number of fibers may be included in the ply twisted yarn, provided that the final fabric meets the performance criteria discussed herein.

[0026] In some other embodiments, at least one first yarn and at least one second yarn are used in a co-knitted weft insertion structure. “Weft insertion” refers to a knitting method in which at least one second yarn is introduced into a knitted structure comprising at least one first yarn (such as when manufacturing an elastic cuff in a knitted glove).

[0027] In some other embodiments, at least one first yarn and at least one second yarn may be used in the fabric in a parallel relationship to each other. As used herein, the term "parallel" means that the individual yarns generally exist side-by-side adjacent to each other in the fabric, and that the yarns are independent and separate from each other, and they are not plyed or twisted together. In knitted fabrics, this type of parallel arrangement in the fabric is also referred to as a type of co-knitted fabric. In a co-knitting manufacturing process, co-knitting is formed by knitting the ends of two separate yarns together (i.e., knitting them together) on a single knitting machine. This structure and process keeps the two distinct yarns close together in the fabric, maintaining their parallel relationship. The process may advantageously include the step of knitting the ends of the yarns during knitting to position one end primarily on the first surface of the garment and the other end primarily on the second surface of the garment. This allows the generally more comfortable end to be positioned primarily on the inside of the garment and the other end primarily on the outside.

[0028] The present invention also relates to a glove or other article comprising a flame-resistant and cut-resistant fabric including all embodiments described herein, the flame-resistant and cut-resistant fabric comprising:

[0029] (a) At least one first yarn comprising at least 50% by weight of heat-resistant polymer fibers based on the total weight of the first yarn, wherein at least 30% by weight of the polymer fibers present in the at least one first yarn are cut-resistant and heat-resistant polymer fibers having a cut resistance of 500 g / L or higher according to ASTM F2992-15; and

[0030] (b) At least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament.

[0031] Based on the total weight of the second yarn, 60 to 95% by weight of the at least one second yarn is halogenated self-extinguishing fiber, and the halogenated self-extinguishing fiber is in contact with the at least one continuous elastic filament, and the second yarn contains no or substantially no inorganic fibers.

[0032] When tested according to NFPA-2112-2018, the fabric has a maximum afterflame time of two seconds or less and a weight loss of 5% or less.

[0033] The at least one first yarn comprises at least 50% by weight of heat-resistant polymer fibers based on the total weight of the first yarn, wherein at least 30% by weight of the polymer fibers present in the at least one first yarn are cut-resistant and heat-resistant polymer fibers having a cut resistance of 500 gf or higher according to ASTM F2992-15.

[0034] "Heat-resistant polymer fiber" refers to a fiber made from a synthetic organic polymer that retains 90% of its original fiber weight when heated to 500°C in air at a rate of 20°C / min. Preferred heat-resistant polymer fibers have a yarn toughness of at least 3 g / denier (2.7 g / dtex). Heat-resistant polymer fibers include para-aramid fibers, aromatic polyamide copolymer fibers, polyindole fibers, polybenzazole fibers, polybenzimidazole fibers, polyimide fibers, and mixtures thereof. Preferred heat-resistant polymer fibers are para-aramid fibers, and preferred para-aramid fibers are poly(p-phenylene terephthalamide) fibers.

[0035] At least one first yarn comprises at least 50 weight percent of heat-resistant polymer fibers based on the total weight of the first yarn. In some embodiments, at least one first yarn comprises at least 60 weight percent of heat-resistant polymer fibers based on the total weight of the first yarn. In some embodiments, at least one first yarn comprises 60 to 85 weight percent of heat-resistant polymer fibers based on the total weight of the first yarn, and in some other embodiments, at least one first yarn comprises 60 to 80 weight percent of heat-resistant polymer fibers based on the total weight of the first yarn. In some embodiments, at least one first yarn comprises 100 weight percent of heat-resistant polymer fibers based on the total weight of the first yarn.

[0036] At least 30% by weight of the polymer fiber present in at least one of the first yarns is a cut-resistant and heat-resistant polymer fiber having a cut resistance of 500 g / cm or higher according to ASTM F2992-15. The cut resistance of the fiber is determined by measuring the cut resistance of a fabric made of 100% woven or knitted fiber at 345 g / m² (10 oz / cm yard) and then measuring the cut resistance (in g / cm) according to ASTM F2992-15.

[0037] Cut-resistant and heat-resistant polymer fibers with a cut strength of 500 g / m or higher according to ASTM F2992-15 include para-aramid fibers, aromatic polyamide copolymer fibers, polyindole fibers, polybenzimidazole fibers, and mixtures thereof. Preferred cut-resistant and heat-resistant polymer fibers are para-aramid fibers, and more preferably, poly(p-phenylene terephthalamide) fibers. If the heat-resistant polymer fiber has sufficient cut resistance, the cut-resistant and heat-resistant polymer fiber in at least one first yarn may be the same as or different from the heat-resistant polymer fiber in at least one first yarn.

[0038] Therefore, it should be understood that cut-resistant and heat-resistant polymer fibers are both heat-resistant polymer fibers as previously defined and cut-resistant fibers as previously defined. Furthermore, at least one first yarn can be 100% cut-resistant and heat-resistant polymer fibers. That is, it should be understood that such a yarn having 100% cut-resistant and heat-resistant polymer fibers therefore has at least 50% by weight heat-resistant polymer fibers and at least 30% by weight cut-resistant and heat-resistant polymer fibers. It should also be understood that at least one first yarn may contain fibers that are heat-resistant polymer fibers as defined herein but not cut-resistant fibers as defined herein. Table 1 provides a guide to the possible percentages of non-cut-resistant and heat-resistant (non--CR HR) polymer fibers and cut-resistant and heat-resistant (CH-HR) polymer fibers, giving selected example compositions.

[0039] Table 1

[0040]

[0041]

[0042] Therefore, it should be understood that at least 30% by weight of the polymer fibers present in at least one first yarn are cut-resistant and heat-resistant polymer fibers as defined herein. In some embodiments, the cut-resistant and heat-resistant polymer fibers are present in at least one first yarn in an amount of 50% to 100% by weight, based on the total amount of polymer fibers in the at least one first yarn. In some other embodiments, the cut-resistant and heat-resistant polymer fibers are present in at least one first yarn in an amount of 80% to 100% by weight, based on the total amount of polymer fibers in the at least one first yarn. In other embodiments, the cut-resistant and heat-resistant polymer fibers are present in at least one first yarn in an amount of 80% to 95% by weight, based on the total amount of polymer fibers in the at least one first yarn.

[0043] In addition to the various example percentages of cut-resistant and heat-resistant polymer fibers and non-cut-resistant and heat-resistant polymer fibers shown in Table 1, in some embodiments, at least one first yarn further comprises other synthetic or organic fibers or filaments that are not heat-resistant polymer fibers; that is, they do not meet the definition of heat-resistant polymer fibers provided herein. Essentially any type of fiber may be included, provided that the final fabric meets the composition and performance criteria discussed herein. Specifically, the composition of at least one first yarn comprises at least 50 weight percent of heat-resistant polymer fibers based on the total weight of the polymer fibers in the first yarn, and wherein at least 30 weight percent of the polymer fibers are cut-resistant and heat-resistant fibers; and the final fabric is a flame-retardant fabric as defined herein, and has a maximum afterflame time of two seconds or less and a weight loss of 5 weight percent or less when tested according to NFPA-2112-2018. Preferably, the fibers or filaments that are not heat-resistant polymer fibers are organic fibers, and in some embodiments are polymer-organic fibers. Furthermore, in some embodiments, if present, the fibers or filaments that are not heat-resistant polymer fibers are synthetic or organic staple fibers.

[0044] In some preferred embodiments, at least one first yarn may further comprise flame-retardant fibers. "Flame-retardant fibers" means a fabric made solely from this fabric that has a char length of 4 inches or less and a afterburning time of 2 seconds or less according to a vertical burning test of ASTM D6143-99; however, the fabric does not meet the cut resistance standards for cut-resistant and heat-resistant polymer fibers previously described herein. Suitable flame-retardant fibers include meta-aramid fibers, wherein the preferred meta-aramid is poly(m-phenylene isophthalamide). Other potentially useful flame-retardant fibers may include blends of meta-aramid and flame-retardant treated (FR) cellulose, FR cotton, FR lyocell fibers, or mixtures thereof. In some embodiments, at least one first yarn contains 30 to 70% by weight of flame-retardant fibers based on the total weight of polymer fibers in the first yarn. In some other preferred embodiments, at least one first yarn contains 50 to 70% by weight of flame-retardant fibers based on the total weight of polymer fibers in the first yarn.

[0045] Both the heat-resistant polymer fiber and the cut-resistant heat-resistant polymer fiber in at least one first yarn are short fibers, preferably having a length of about 2 to 20 cm, more preferably about 3.5 to 6 cm. Both the heat-resistant polymer fiber and the cut-resistant heat-resistant polymer fiber in at least one first yarn are short fibers, preferably having a diameter of 5 to 25 micrometers and a linear density of 0.5 to 7 dtex. Furthermore, in some embodiments, if present, the flame-retardant fiber or the fiber or filament that is not a heat-resistant polymer fiber is a short fiber with dimensions similar to the aforementioned ranges for the heat-resistant polymer fiber and the cut-resistant heat-resistant polymer fiber.

[0046] In some embodiments, based on the total weight of the first yarn, at least one first yarn comprises at least 50 weight percent of heat-resistant polymer fibers, and wherein at least 30 weight percent of the polymer fibers present in the at least one first yarn are cut-resistant and heat-resistant polymer fibers having a cut resistance of 500 g / m or higher according to ASTM F2992-15. The at least one first yarn further has a sheath / core structure, wherein the sheath comprises cut-resistant and heat-resistant polymer fibers, and the core comprises inorganic fibers. When an application desires or requires excellent cut resistance, it is preferable to add at least one inorganic fiber to the yarn. The use of a sheath / core structure is advantageous because the short sheath fibers provide a covering and shield the inorganic filaments in the core from direct frictional contact with the skin, resulting in improved comfort in fabrics containing sheath / core yarns.

[0047] In some embodiments, when inorganic fibers are present in at least one first yarn, the inorganic fibers are present in an amount of 15 to 40 weight percent of the total weight of the first yarn. Similarly, based on the total weight of the first yarn, the maximum amount of heat-resistant polymer fibers in these core-sheath first yarns is 85 weight percent when inorganic fibers are present. In some preferred embodiments, the core-sheath yarn has 60 to 80 weight percent of heat-resistant polymer fibers in the sheath and 20 to 40 weight percent of organic fibers in the core. Preferably, the inorganic fibers in the core are steel or tungsten. Preferably, the fibers in the core are present as one or more continuous filaments.

[0048] Sheath fibers can be wrapped or spun around an inorganic filament core. Specifically, this can be achieved by known means, such as conventional ring spinning, which includes those that modify conventional processes such as those utilizing COTSON technology; core-spun spinning such as DREF spinning; air-jet spinning using so-called core insertion with Murata (now Muratec) jet spinning; free-end spinning, etc. Preferably, short fibers are bonded around the inorganic filament core at a density sufficient to cover the core. The degree of coverage depends on the spinning process used; for example, core-spun spinning such as DREF spinning (disclosed, for example, in U.S. Patent Nos. 4,107,909; 4,249,368; and 4,327,545) provides better coverage than ring spinning. Conventional ring spinning provides only partial coverage of the central core, but even partial coverage can provide sufficient sheath / core coverage. The sheath may also include fibers of some other material, to a degree tolerable due to a reduction in cut resistance caused by that other material.

[0049] For example, in its simplest practical application, the incorporation of at least one inorganic filament as a core in this embodiment of the first yarn can be achieved by passing a heat-resistant and cut-resistant roving, sliver, or aggregate of fibers and optionally non-heat-resistant fibers through multiple sets of drafting rollers to cause the drafted fiber bundle to be ring-twisted into a single yarn. At least one inorganic filament is typically fed from a bobbin through a set of feed rollers and subsequently into the short fibers before the last set of drafting rollers. Since the inorganic core filaments are not elastomers, they do not need to be excessively tensioned during yarn insertion; only sufficient tension is applied to the sheath and core, as is conventionally used.

[0050] At least one of the first yarns in the sheath / core yarn form typically comprises 15-50% by weight of inorganic filaments, wherein the overall linear density of the sheath / core yarn is 100 to 5000 dtex. Depending on the specific application or the required or desired level of cut protection, the core containing inorganic fibers can be a monofilament or a multifilament, and is preferably a single metal filament or several metal filaments. Metal filaments refer to filaments or threads made of ductile metals such as stainless steel, copper, aluminum, bronze, tungsten, etc., or metal fiber structures commonly referred to as "microsteel." Stainless steel is a preferred metal. Metal filaments are typically continuous threads. Available metal filaments have diameters from 1 to 150 micrometers, and preferably from 25 to 75 micrometers.

[0051] In some embodiments, the inorganic fiber is a glass filament. It can be one or more glass filaments, such as 110 dtex (100 denier) glass filaments. However, glass is less preferred because its cut resistance / linear density is lower than that of metal, and it is even more critical if the yarn is used for gloves, sleeves, etc. (where the fabric comes into contact with the skin), that the glass is essentially covered by a short fiber sheath to minimize skin irritation. Therefore, in many embodiments, the inorganic fiber is a metal filament.

[0052] Similarly, it should be understood that for these sheath / core yarns, the cut-resistant heat-resistant polymer fibers are both heat-resistant polymer fibers as previously defined and cut-resistant fibers as previously defined. It should also be understood that at least one first yarn may contain fibers that are heat-resistant polymer fibers as defined herein but not cut-resistant fibers as defined herein. Table 2 provides a guide to the possible percentages of total heat-resistant (CH-HR) polymer fibers and total inorganic filaments in at least one first yarn, gives selected example compositions, and further provides possible percentages indicating the possible amounts of non-cut-resistant heat-resistant (non-CRHR) polymer fibers and cut-resistant heat-resistant (CH-HR) polymer fibers.

[0053] Table 2

[0054]

[0055] At least one second yarn has a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament, wherein 60 to 95% by weight of the at least one second yarn is halogenated self-extinguishing fiber based on the total weight of the second yarn, and the halogenated self-extinguishing fiber is in contact with the at least one continuous elastic filament, and the second yarn contains no or substantially no inorganic fibers.

[0056] At least one second yarn has a sheath / core structure, wherein the sheath of a halogenated self-extinguishing short fiber contacts and covers the core of at least one continuous elastic filament. It is believed that the halogenated self-extinguishing short fiber provides an active fire-extinguishing covering for the core of at least one continuous elastic filament. This differs from a covering fiber that provides a “structural shield” for the core, i.e., the covering fiber simply chars and remains in place when exposed to flame, and thus provides a structural barrier between the flame and the elastic core. Alternatively, the sheath of the halogenated self-extinguishing short fiber decomposes in the presence of high heat flux (such as in a flame), releasing halogen gases that displace local oxygen in the yarn and hinder combustion of the core of at least one continuous elastic filament. Therefore, it is believed that the halogenated self-extinguishing short fiber should not only cover the core but also be in direct contact with it to locally displace oxygen on the surface of the core of at least one continuous elastic filament.

[0057] The sheath of halogenated self-extinguishing short fibers can be wrapped or spun around at least one continuous elastic filament. This can be achieved by known means, such as conventional ring spinning, which includes those that modify conventional processes such as those utilizing COTSON technology; core-spun spinning such as DREF spinning; air-jet spinning using so-called core insertion with Murata (now Muratec) jet spinning; free-end spinning, etc. Preferably, the short fibers are bonded around the core of at least one continuous elastic filament at a density sufficient to cover the core. The degree of coverage depends on the process used in spinning; for example, core-spun spinning such as DREF spinning (disclosed, for example, in U.S. Patent Nos. 4,107,909; 4,249,368; and 4,327,545) provides better coverage than ring spinning. Conventional ring spinning only provides partial coverage of the central core, but even partial coverage is assumed herein to be a possible sheath / core structure.

[0058] It is believed that the fire extinguishing effect of halogenated self-extinguishing short fibers is sufficient when, based on the total weight of the second yarn, at least 60 to 95% by weight of at least one second yarn is halogenated self-extinguishing fiber. In some embodiments, it is desirable that at least 80 to 95% by weight of at least one second yarn is halogenated self-extinguishing fiber based on the total weight of the second yarn. The sheath may also include fibers of other materials to a degree that allows for tolerable reduction in fire extinguishing effectiveness due to these other materials.

[0059] Halogenated self-extinguishing fibers include those made from halogenated polymers. A particularly preferred type of halogenated self-extinguishing fiber is a fiber made from a modified polyacrylonitrile polymer. "Modified polyacrylonitrile polymer" means, preferably, that the polymer is a copolymer comprising 30 to 70 weight percent acrylonitrile and 70 to 30 weight percent a halogenated vinyl monomer. The halogenated vinyl monomer is at least one monomer selected from, for example, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, etc.

[0060] In some embodiments, the modified polyacrylonitrile copolymer is one of acrylonitrile in combination with vinylidene chloride. In some embodiments, the modified polyacrylonitrile copolymer further comprises one or more antimony oxides. In some preferred embodiments, the modified polyacrylonitrile copolymer comprises less than 1.5 weight percent of one or more antimony oxides, or the copolymer is completely antimony-free. Polymers with very low antimony content and antimony-free polymers can be manufactured by limiting the amount of any antimony compound added to the copolymer during manufacturing or by completely eliminating any antimony compound. Representative methods for modifying polyacrylonitrile polymers (including those that can be modified in this way) are disclosed in U.S. Patent No. 3,193,602 (with 2 weight percent of antimony trioxide); U.S. Patent No. 3,748,302 (manufactured with various antimony oxides present in amounts of at least 2 weight percent and preferably no more than 8 weight percent); and U.S. Patent Nos. 5,208,105 and 5,506,042 (with 8 to 40 weight percent of antimony compounds). In some embodiments, the modified polyacrylonitrile polymer has a LOI of at least 26. In a preferred embodiment, the modified polyacrylonitrile polymer has an LOI of at least 26 and is also antimony-free.

[0061] The halogenated self-extinguishing short fibers in at least one second yarn are preferably short fibers having a length of about 2 to 9 cm, more preferably about 3.5 to 6 cm. The halogenated self-extinguishing short fibers in at least one second yarn are preferably short fibers having a diameter of 5 to 25 micrometers and a linear density of 0.5 to 7 dtex.

[0062] The fabric contains at least one second yarn with a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament. The halogenated self-extinguishing fibers are in contact with the at least one continuous elastic filament, thereby eliminating the need for the entire surface of the elastic filament to be practically completely covered by the short fiber sheath.

[0063] In some embodiments, preferably at least 90% of the core is covered by the sheath, as observed under a microscope, where the yarn is in a relaxed state; that is, where the sheath-core yarn is observed without tension. The actual coverage of the core may depend on the degree of yarn tension; however, it is believed that the modified polyacrylonitrile fibers provide their shielding benefits as long as they are in contact with the elastic core.

[0064] In some embodiments, 5 to 40% by weight of the total weight of at least one second yarn is at least one continuous elastic filament. In some embodiments, the ring-spun second yarn has a core comprising at least one elastic filament and partially covered with halogenated self-extinguishing short fibers. In some preferred embodiments, the core of the elastic filament accounts for 5 to 25% by weight of the total sheath / core yarn with a linear density of 100 to 1500 dtex.

[0065] As used herein, "a core comprising at least one continuous elastic filament" means a core formed of or containing filaments of an elastomer, preferably having the ability to rapidly return to its original length after repeated stretching, even up to at least twice its original length. Preferred elastic cores include polyurethane-based yarns, such as spandex or elastic fibers; however, any fiber generally possessing stretch and recovery properties can be used. Suitable well-known elastic yarns also include those marketed under trademarks. and Products for sale.

[0066] Preferred continuous elastic filaments are spandex fibers. As used herein, “spandex” has its usual definition, namely, a man-made fiber in which the fiber-forming material is a long-chain synthetic polymer consisting of at least 85% by weight of segmental polyurethane. Segmental polyurethanes of the spandex type are those described, for example, in U.S. Patent Nos. 2,929,801; 2,929,802; 2,929,803; 2,929,804; 2,953,839; 2,957,852; 2,962,470; 2,999,839; and 3,009,901.

[0067] In some methods of manufacturing spandex elastic filaments, coalescing jets are used to fix the spandex filaments immediately after extrusion. It is also known that dry-spun spandex filaments become sticky immediately after extrusion. Grouping a set of these sticky filaments together and using a combination of coalescing jets produces a coalesced multifilament yarn, which is then typically coated with silicone or other finishing agents before winding to prevent sticking to the packaging. This coalesced group of filaments is actually a large number of tiny individual filaments adhered to each other along their length, which is superior in many respects to a single spandex filament of the same linear density.

[0068] The elastic filaments in the elastic monofilament yarn are preferably continuous filaments and may exist in the second yarn as one or more individual filaments or as one or more bundled filament groups. However, it is preferred to use only one bundled filament group in the preferred elastic monofilament yarn. Whether present as one or more individual filaments or as one or more bundled filament groups, the linear density of the relaxed elastic filament is typically between 17 and 560 dtex (15 to 500 denier), and the preferred linear density range is 44 to 220 dtex (40 to 200 denier).

[0069] Preferably, before being incorporated into the short fibers, at least one continuous elastic filament is incorporated into the second yarn under tension by pulling or stretching it using a feed speed of at least one continuous elastic filament that is slower than the final second yarn speed. This pulling can be described as the draw ratio of the continuous elastic filament, which is the final second yarn speed divided by the feed speed of the continuous elastic filament.

[0070] Typical draw ratios range from 1.5 to 5.0, with 1.5 to 3.50 being preferred. Low draw ratios result in less elastic recovery, while very high draw ratios make the yarn difficult to work with and the fabric too tight and uncomfortable. The optimal draw ratio also depends on the weight percent content of the elastic core. Tensioners can also be used to tighten and stretch elastic fibers, but are less preferred due to the difficulty in reproducing and controlling tension and stretch. The optimal draw ratio for each fabric is ultimately determined based on the desired fit and feel.

[0071] For example, in its simplest practical application, at least one continuous elastic filament can be incorporated into a second yarn of halogenated self-extinguishing staple fibers by passing a roving, sliver, or assembly of halogenated self-extinguishing staple fibers through multiple sets of drafting rollers to allow the drafted fiber bundle to be ring-twisted into a single yarn. The at least one continuous elastic filament is typically fed from a bobbin through a set of feed rollers and subsequently into the staple fibers before the last set of drafting rollers. The relative surface speed of the feed rollers relative to the drafting rollers, which is slower, is increased or decreased to determine the amount of elastic stretch and tension in the final ring-twisted single yarn using conventional techniques.

[0072] In some embodiments, the sheath of at least one second yarn may further comprise heat-resistant polymer fibers as previously described herein. In some other embodiments, the sheath of at least one second yarn may further comprise cut-resistant and heat-resistant polymer fibers as previously described herein.

[0073] In some embodiments, the sheath of at least one second yarn may further comprise flame-retardant fibers. "Flame-retardant" fibers mean fabrics made solely from this fabric that have a char length of 4 inches or less and an afterburning time of 2 seconds or less according to a vertical burning test of ASTM D6143-99. Suitable flame-retardant fibers include aramid fibers, with meta-aramid fibers being particularly preferred; preferred meta-aramids are poly(m-phenylene isophthalamide). Potentially useful flame-retardant fibers include meta-aramids, polyamide-imides, flame-retardant treated (FR) cellulose, FR cotton, FR lyocell fibers, or mixtures thereof. In some embodiments, based on the total weight of the polymer fibers in at least one second yarn, at least one second yarn preferably has 5% to up to 35% flame-retardant fibers. Furthermore, in some embodiments, based on the total weight of the polymer fibers in at least one first yarn, at least one first yarn preferably has 5% to up to 35% flame-retardant fibers.

[0074] The second yarn may contain any number of fibers, provided that the second yarn and the final fabric meet the performance criteria discussed herein.

[0075] If used in the second yarn, the heat-resistant polymer fiber, cut-resistant heat-resistant polymer fiber, or flame-resistant fiber is preferably a short fiber, preferably having a length of about 2 to 20 cm, more preferably about 3.5 to 6 cm. Furthermore, if used in the second yarn, the heat-resistant polymer fiber, cut-resistant heat-resistant polymer fiber, and flame-resistant fiber are preferably short fibers, preferably having a diameter of 5 to 25 micrometers and a linear density of 0.5 to 7 dtex.

[0076] In some embodiments, the sheath of at least one second yarn may further comprise antistatic fibers known in the art or fibers capable of reducing charge accumulation in the yarn or the resulting fabric. In some preferred embodiments, the sheath of at least one second yarn comprises at least 1-5 weight percent of antistatic fibers based on the total weight of at least one second yarn. Preferred antistatic fibers are those that function by the presence of carbon in the fiber (as a carbon coating or carbon particles); particularly antistatic fibers that help eliminate charge accumulation but are not considered conductive in a practical sense. In some embodiments, aramid fibers containing carbon particles are preferred.

[0077] In a preferred embodiment, the second yarn contains no or substantially no inorganic fibers. The cut resistance benefits of any inorganic fibers are provided by the first yarn, eliminating the need for additional inorganic fibers in the second yarn for most intended applications.

[0078] In some embodiments, the twisted yarn is formed from at least one first yarn and at least one second yarn. The twisted yarn is made by twisting at least two separate monofilaments together. The phrase "twisting at least two separate monofilaments together" means twisting two monofilaments together rather than one yarn completely covering another. This distinguishes the twisted yarn from a cover yarn or wrapped yarn (where the first monofilament is substantially or completely wrapped around the second monofilament, such that ideally only the first monofilament is exposed on the surface of the resulting cover yarn).

[0079] In a preferred embodiment, the twisted yarn is made of at least two single yarns, the first single yarn being (a) at least one first yarn comprising at least 50 weight percent of heat-resistant polymer fibers based on the total weight of the first yarn, and wherein at least 30 weight percent of the polymer fibers present in the at least one first yarn are cut-resistant heat-resistant polymer fibers having a cut resistance of 500 g / m or higher according to ASTM F2992-15, the at least one first yarn further having a sheath / core structure, wherein the sheath comprises cut-resistant heat-resistant polymer fibers and the core comprises inorganic fibers; and the second single yarn being (b) at least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament, wherein 60 to 95 weight percent of the at least one second yarn is halogenated self-extinguishing fiber based on the total weight of the second yarn, and the halogenated self-extinguishing fiber is in contact with the at least one continuous elastic filament, the second yarn containing no or substantially no inorganic fibers. Each single yarn may have some twist.

[0080] In some embodiments, the twisted yarn made of two single yarns has a linear density of 200 to 3000 dtex. Individual short fibers in either single yarn may have a linear density of 0.5 to 7 dtex, with a preferred linear density range of 1.5 to 3 dtex. The twisted yarn and the single yarns constituting those twisted yarns may include other materials, provided that the function or properties of the yarn or the fabric made from it are not affected for the desired application.

[0081] Ply-twisted yarns can be made from single yarns by the method disclosed in Prickett’s U.S. Patent No. 6,952,915, and the ply-twisted yarns can have a wide range of ply twists disclosed therein.

[0082] The twisted yarn can then be combined with other identical or different twisted yarns to form a yarn bundle to form a fabric, or a single twisted yarn can be used to form the fabric, depending on the desired fabric requirements. For example, two or more of the described twisted yarns can be combined to form a yarn bundle, which can be fed into the knitting machine with or without twisting. Alternatively, the yarn bundle can be made from one or more of the described twisted yarns with one or more different single yarns to impart the desired properties to the final fabric. Since modern knitting machines can knit fabrics from multiple twisted yarn feeds, the twisted yarn bundle fed into the machine does not need to be twisted, although it can be twisted if necessary.

[0083] When a coreless yarn is unavailable, at least one first yarn used in the preferred twisted yarn is preferably a ring-spun single 420 dtex (380 denier, equivalent to 14 cotton yarn count) yarn. This yarn has a poly(p-phenylene terephthalamide) (PPD-T) staple fiber sheath, with a cut length of 3.8 cm (1.5 inches) and a filament density of 1.7 dtex / filament (1.5 denier / filament).

[0084] At least one second yarn used in the preferred twisted yarn is a ring-spun single 330 dtex (295 denier, equivalent to 18 cotton yarn count) yarn. This yarn has a modified polyacrylonitrile staple fiber sheath that at least partially covers the elastic core filament, the modified polyacrylonitrile staple fiber having a cut length of 4.8 cm (1.89 inches) and a filament density of 1.7 dtex / filament (1.5 denier / filament). The elastic core is a 78 dtex (70 denier) spandex polymerized filament yarn with a draw ratio of 3.0 (approximately 200% elongation). In some preferred embodiments, approximately 92% by weight of the second yarn consists of modified polyacrylonitrile staple fibers, and 8% by weight of the second yarn is the elastic core.

[0085] The present invention also relates to a cut-resistant woven or knitted fabric made of a yarn or yarn bundle comprising at least one first yarn and at least one second yarn. The present invention further relates to a cut-resistant woven or knitted fabric made of a ply-twisted yarn or a yarn bundle comprising ply-twisted yarn, wherein the ply-twisted yarn comprises at least one first yarn and at least one second yarn, as described herein.

[0086] Specifically, the present invention relates to a cut-resistant woven or knitted fabric made of a twisted ply yarn, the twisted ply yarn being made of at least two single yarns, the first single yarn being (a) at least one first yarn containing at least 50% by weight of heat-resistant polymer fibers based on the total weight of the first yarn, and wherein at least 30% by weight of the polymer fibers present in at least one first yarn are cut-resistant and heat-resistant polymer fibers, according to ASTM F2992-15, the cut-resistant and heat-resistant polymer fiber has a cut resistance of 500 g / m or higher; and the second yarn is (b) at least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing short fibers and a core comprising at least one continuous elastic filament, wherein, based on the total weight of the second yarn, 60 to 95% by weight of the at least one second yarn is halogenated self-extinguishing fiber, and the halogenated self-extinguishing fiber is in contact with the at least one continuous elastic filament, the second yarn being free of or substantially free of inorganic fibers; and the fabric having a maximum afterflame time of two seconds or less and a weight loss of 5% or less when tested according to NFPA-2112-2018.

[0087] In some embodiments, the first single yarn comprises at least one first yarn, the at least one first yarn further having a sheath / core structure having a sheath comprising cut-resistant and heat-resistant polymer fibers and a core comprising inorganic fibers.

[0088] At least one first yarn and at least one second yarn work synergistically together in the yarn and fabric. At least one continuous elastic filament incorporated into the yarn provides improved stretch and recovery, while heat-resistant short fibers provide structure in flame, and heat-resistant and cut-resistant organic short fibers and inorganic filaments (if present) provide excellent cut resistance to the yarn and fabric. Fabrics made from such yarns are soft, comfortable, non-abrasive, and cut-resistant.

[0089] The twisting of the first and second yarns is preferred because it helps keep the elastomer yarn stretched and prevents it from looping when relaxed. However, acceptable fabrics can be produced if the sheath / core elastic yarn is bundled with other yarns (without twisting) and co-fed into a knitting or weaving apparatus with good tension control. When the bundle consists of twisted yarns, yarn tension control during knitting and weaving is less important.

[0090] The preferred fabric is a knitted fabric, and any suitable knit pattern is acceptable. Cut resistance and comfort are affected by the tightness of the knit and the tightness can be adjusted to meet any specific need. A very effective combination of cut resistance and comfort has been found in, for example, single-knit fabrics and terry knit patterns for many cut-resistant articles. The fabric has a density of approximately 4 to 30 oz / yd. 2 Preferred 6 to 25 oz / yd 2 The basis weight, with fabrics at the high end of the basis weight range providing more heat and cut protection.

[0091] Test methods

[0092] Afterflame and weight loss are determined according to NFPA 2112-2018, "Standard for fire-resistant clothing to protect industrial workers from short-term heat exposure in a fire," specifically the procedure outlined in Section 8.8 of that standard.

[0093] The determination of “heat-resistant polymer fibers” as discussed in this article can be achieved using the standard practice for general techniques of Thermogravimetric Analysis (TGA) Coupled With Infrared Analysis (TGA / IR) as described in ASTM E2105-2016. This involves analyzing whether the synthetic organic polymer retains 90 percent of its original fiber weight by heating the sample in air to 500°C at a rate of 20°C / min.

[0094] Example

[0095] Knitted fabrics made from twisted yarn

[0096] Examples of twisted yarns and knitted fabrics made from these yarns are shown in Examples 1, 2, and 3, as well as Comparative Example A, and are summarized in Table 6.

[0097] Example 1

[0098] Twisted elastic yarn is prepared by twisting the first yarn and the second yarn together.

[0099] The first yarn is a 14-count cotton core-sheath yarn spun on a ring spinning machine, consisting of a para-aramid fiber sheath and a 50-micron stainless steel core. The para-aramid fiber is a 2-inch poly(p-phenylene terephthalamide) staple fiber.

[0100] The second yarn is an 18-count cotton core-sheath yarn made by spinning a 2-inch modified polyacrylonitrile short fiber core around a 70-denier spandex core on a ring spinning machine; when the spandex core is incorporated into the core-sheath yarn, it is stretched by 3X.

[0101] The resulting twisted elastic yarn, produced by twisting the first and second yarns together, has a total cotton yarn count of 16 / 2 or 675 denier. The relative amounts of the yarn components are shown in Table 3.

[0102] The resulting twisted elastic yarn was knitted into 13-gauge sleeves on a Shima-Seiki glove knitting machine. The resulting sleeves exhibited excellent hand feel and fit. A fabric sample of the resulting sleeves was subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric had a 0-second afterflame time, and the weight consumed during the test was 4.8%, which is below the maximum afterflame time requirement of 2 seconds and the 5% weight loss limit allowed in the specification.

[0103] Table 3

[0104]

[0105] Example 2

[0106] Repeat the twisted elastic yarn of Example 1, but with the following exceptions.

[0107] The first yarn is a 26-count cotton yarn with a para-aramid fiber sheath and a stainless steel core made of 35-micron stainless steel wire. The second yarn is a 32-count cotton yarn with a modified polyacrylonitrile fiber sheath and a 40-denier spandex core that is stretched 3X during spinning.

[0108] Similar to Example 1, the resulting twisted elastic yarn, produced by twisting the first and second yarns together, has a total cotton yarn count of 29 / 2 or 371 denier. The relative amounts of the yarn components are shown in Table 4.

[0109] The resulting twisted elastic yarn was knitted into 18-gauge sleeves on a Shima-Seiki glove knitting machine. The resulting sleeves exhibited excellent fit characteristics. Fabric samples of the resulting sleeves were washed to remove knitting oils and finishing agents, and subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric had 0 seconds of afterflame, and the weight consumed during the test was 3.3%, which is lower than the maximum afterflame requirement of 2 seconds and the 5% weight loss limit allowed in the specification.

[0110] Table 4

[0111]

[0112] Example 3

[0113] Repeat the twisted elastic yarn of Example 1, but with the following exceptions.

[0114] The first yarn is a 19.5-count cotton yarn with a para-aramid fiber sheath and a stainless steel core, the stainless steel core being made of 45-micron stainless steel wire stretched 3X during spinning. The second yarn is a 32-count cotton yarn with a sheath core and a 40-denier spandex core; however, the sheath is a blend of 82% by weight modified polyacrylonitrile staple fibers and 10% by weight 2-inch cut length meta-aramid staple fibers; specifically, the meta-aramid blend contains 93% by weight poly(m-phenylene isophthalamide) staple fibers, 5% by weight poly(p-phenylene terephthalamide) staple fibers, and 2% by weight carbon core nylon antistatic fibers.

[0115] Similar to Example 1, the resulting twisted elastic yarn, produced by twisting the first and second yarns together, has a total cotton yarn count of 24 / 2 or 439 denier. The relative amounts of the yarn components are shown in Table 5.

[0116] The resulting twisted elastic yarn was knitted into a size 18 sleeve on a Shima-Seiki glove knitting machine. The resulting sleeve has excellent fit characteristics.

[0117] Fabric samples of the produced sleeves were washed to remove knitting oils and finishing agents, and then subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric had a 0-second afterflame time, and the weight consumed during the test was 3.9%, below the maximum afterflame time requirement of 2 seconds and the 5% weight loss limit allowed in the specification.

[0118] Another fabric sample of the produced sleeves was subjected to a flame test according to the fire-resistant glove test method detailed in EN407:2020. It was found that the resulting stretched fabric exhibited 0 seconds of afterflame and 0 seconds of afterglow after exposure to flame for 3 and 15 seconds, respectively, which is below the requirement of 2 seconds of maximum afterflame and 5 seconds of maximum afterglow for achieving the highest level specified in the standard.

[0119] Table 5

[0120]

[0121] *A practical blend of 93wt% meta-aramid fiber, 5wt% para-aramid fiber and 2wt% carbon core nylon antistatic fiber.

[0122] Comparison Example A

[0123] A comparative twisted elastic yarn similar to that in Example 3 was prepared; however, the first yarn, with a para-aramid fiber sheath and a stainless steel core, was made from 1.5-inch poly(p-phenylene terephthalamide) staple fibers and a 45-micron stainless steel core. The second yarn (also a 32-count cotton core-sheath yarn) had a nylon staple fiber sheath of only 1.5 inches in length core-spun around a 40-denier spandex core.

[0124] The resulting 24's-2 count twisted yarn was knitted into a size 18 sleeve on a Shima-Seiki glove knitting machine. The resulting sleeve has excellent fit characteristics.

[0125] However, flame tests were conducted on the produced samples according to the fire-resistant glove test method detailed in EN407:2020. It was found that the resulting stretched fabric exhibited at least 25 seconds of afterflame reactivation after exposure to flame for 3 seconds, exceeding the minimum 20-second maximum afterflame reactivation requirement specified in the standard.

[0126] Because there was too much afterflame even after only 3 seconds of flame exposure, subsequent tests were not conducted, including the 15-second exposure test in EN407 and the 12-second exposure test in NFPA-2112.

[0127] Table 6

[0128]

[0129] Knitted fabric made by knitting two parallel ends together

[0130] Examples of knitted fabrics made by co-knitting yarns by supplying individual ends or individual end bundles to the knitting machine are shown in Example 4 and Comparative Example B, and are summarized in Table 4.

[0131] Example 4

[0132] The first end (2 strands of para-aramid ring-spun yarn, each strand of which is made of 2-inch poly(p-phenylene terephthalamide) staple yarn, wherein each strand of the 2 strands has a cotton yarn count of 16) is knitted together with the second end of the 18-cotton yarn core of Example 1.

[0133] Then, the two ends are knitted together on a size 13 knitting machine to form the sleeve. The resulting sleeve has an excellent hand feel and a close fit.

[0134] Fabric samples of the produced sleeves were washed to remove knitting oils and finishing agents, and then subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric exhibited 0 seconds of afterflame and consumed 2.5% of its weight during the test, which is below the maximum afterflame requirement of 2 seconds and the 5% weight loss limit allowed in the specification.

[0135] Comparison Example B

[0136] One end of a 12-count modified polyacrylonitrile ring-spun yarn made from 2-inch modified polyacrylonitrile staple fibers was co-knitted with one end of an 18-count cotton core-sheath yarn from Example 1. The two ends were co-knitted into a sleeve on a 13-gauge knitting machine. The resulting sleeve has excellent hand feel and a close fit.

[0137] The produced samples were washed to remove knitting oil and finishing agents, and then subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric had an afterflame time of 2.3 seconds, and the weight consumed during the test was 5.8%, exceeding the maximum afterflame time requirement of 2 seconds and the 5% weight loss limit allowed in the specification.

[0138] Table 7

[0139]

[0140] Knitted fabrics made from weft threads

[0141] Examples of knitted fabrics made by weft-knitting yarns are shown in Example 3 and comparative examples B and C, and summarized in Table 4.

[0142] Example 5

[0143] The first end (i.e., two strands of para-aramid ring-spun yarn, each strand made of 2-inch poly(p-phenylene terephthalamide) staple fiber yarn, wherein each strand of the two yarns has a yarn count of 16) is co-knitted with the second end (i.e., a modified polyacrylonitrile fiber sheath-spandex core elastic yarn (made by ring spinning 1200 denier core-spun fiber and 440 denier spandex core (stretched 3X during yarn spinning)) to produce a fire-resistant yarn. The elastic core yarn consists of approximately 12% spandex and 88% modified polyacrylonitrile staple fiber.

[0144] On a Shima-Seiki flat knitting machine, a weft insertion technique (introducing modified polyacrylonitrile fiber sheath-spandex core elastic yarn every three stitches) is used to knit the first and second ends together to form a 13-gauge knitted cuff. The resulting sleeve has excellent fit characteristics.

[0145] The produced samples were washed to remove knitting oil and finishing agents, and then subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric exhibited 0 seconds of afterflame and 4% weight loss during the test, which is below the maximum afterflame requirement of 2 seconds and the 5% weight loss limit allowed in the specification.

[0146] Comparison Example C

[0147] In Example 5, the first end of a two-strand para-aramid ring-spun yarn was combined with a different second end, which was a polyester-wrapped rubber elastic cord from Supreme Elastic Corporation. The first and second ends were co-knitted on a Shima-Seiki flat knitting machine to produce an elastic cuff. The elastic cord composition was estimated to be 75% polyester and 25% rubber. The two ends were co-knitted using a weft insertion technique that introduced the polyester-wrapped rubber elastic cord into every three stitches of a 13-gauge knitted sleeve. The resulting sleeve exhibited excellent fit characteristics.

[0148] Fabric samples of the produced sleeves were washed to remove knitting oils and finishing agents, and then subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting fabric had an afterflame time of 43 seconds, and the weight consumed during the test was 9%, exceeding the maximum afterflame time of 2 seconds and the 5% weight loss limits allowed in the specification.

[0149] Comparison Example D

[0150] The four ends of a ring-spun yarn made from 2-inch modified polyacrylonitrile staple fibers (each yarn having a cotton count of 35) are co-knitted with a core-sheath elastic yarn having a modified polyacrylonitrile fiber sheath and a spandex core. The core-sheath elastic yarn is produced by ring spinning a 1200-denier modified polyacrylonitrile staple fiber yarn with a 440-denier spandex core, with the spandex stretched 3X during spinning to produce a core-sheath elastic yarn composed of approximately 12% spandex and 88% modified polyacrylonitrile staple fibers. In a 13-gauge knitted sleeve on a glove knitting machine, the elastic yarn is co-knitted in every three stitches using a weft insertion technique. The resulting sleeve exhibits excellent fit characteristics.

[0151] Fabric samples of the produced sleeves were washed to remove knitting oils and finishing agents, and then subjected to flame testing according to the fire-resistant glove test method detailed in NFPA-2112-2018. It was found that the resulting stretched fabric exhibited 0 seconds of afterflame and consumed 10% of its weight during the test, which is below the maximum afterflame requirement of 2 seconds allowed in the specification but above the 5% weight loss limit.

[0152] Table 8

[0153]

Claims

1. A flame and cut resistant fabric comprising: (a) at least one first yarn comprising at least 50 weight percent of heat resistant polymeric fibers based on the total weight of the polymeric fibers in the first yarn, wherein at least 30 weight percent of the polymeric fibers present in the at least one first yarn are cut resistant heat resistant polymeric fibers having a cut resistance of 500 grams force or more according to ASTM F2992-15; and (b) at least one second yarn having a sheath / core structure having a sheath of halogenated self-extinguishing staple fibers and a core comprising at least one continuous elastic filament, wherein 60 to 95 weight percent of the at least one second yarn is halogenated self-extinguishing fibers based on the total weight of the second yarn, and the halogenated self-extinguishing fibers are in contact with the at least one continuous elastic filament, the second yarn being free of inorganic fibers; wherein the fabric has a maximum afterflame time of two seconds or less and a weight loss of 5 weight percent or less when tested according to NFPA-2112-2018.

2. The fabric of claim 1, wherein, The at least one first yarn has a sheath / core structure having a sheath comprising the cut resistant heat resistant polymeric fibers and a core comprising inorganic fibers.

3. The fabric of claim 1 or 2, wherein, The heat resistant polymeric fibers or the cut resistant heat resistant polymeric fibers are aramid copolymer, para-aramid, polyindole, polybenzimidazole, polyimide, or mixtures thereof.

4. The fabric of claim 3, wherein, The heat resistant polymeric fibers or the cut resistant heat resistant polymeric fibers are para-aramid.

5. The fabric of claim 3, wherein, The para-aramid fibers are poly(paraphenylene terephthalamide).

6. The fabric of claim 1, wherein, The at least one first yarn further comprises cut resistant flame resistant fibers.

7. The fabric of claim 6, wherein, The flame resistant fibers are meta-aramid, polyamide-imide, flame retardant treated (FR) cellulose, FR cotton, FR lyocell, or mixtures thereof.

8. The fabric of claim 7, wherein, The flame resistant fibers are meta-aramid.

9. The fabric of claim 8, wherein, The meta-aramid is poly(metaphenylene isophthalamide).

10. The fabric of claim 1, wherein, 80 to 95 weight percent of the total weight of the at least one second yarn is the halogenated self-extinguishing fibers.

11. The fabric of claim 10, wherein, The halogenated self-extinguishing fibers are modacrylic fibers.

12. The fabric of claim 1, wherein, 5 to 40 weight percent of the total weight of the at least one second yarn is the at least one continuous elastic filament.

13. The fabric of claim 12, wherein, The at least one continuous elastic filament is spandex filament.

14. The fabric of claim 1, wherein, The inorganic fibers are metal filaments.

15. The fabric of claim 1, wherein, The inorganic fibers are glass filaments.

16. The fabric of claim 1, wherein, The sheath of the at least one second yarn further comprises heat resistant polymeric fibers.

17. The fabric of claim 1, wherein, The sheath of the at least one second yarn further comprises cut resistant flame resistant fibers.

18. The fabric of claim 17, wherein, The flame resistant fibers are meta-aramid, polyamide-imide, flame retardant treated (FR) cellulose, FR cotton, FR lyocell, or mixtures thereof.

19. The fabric of claim 18, wherein, The flame resistant fibers are meta-aramid.

20. The fabric of claim 19, wherein, The meta-aramid is poly(metaphenylene isophthalamide).

21. The fabric of claim 1, wherein, The sheath of the at least one second yarn further comprises antistatic fibers.

22. The fabric of claim 1, comprising a cabled twisted yarn of the at least one first yarn and the at least one second yarn.

23. The fabric of claim 1, wherein, The fabric is a knit fabric.

24. The fabric of claim 1, having a co-knit construction of the at least one first yarn and the at least one second yarn.

25. The fabric of claim 24, wherein, The at least one first yarn and the at least one second yarn are in parallel relationship to each other in the co-knit construction.

26. The fabric of claim 24, wherein, The at least one second yarn is a weft yarn in the co-knit construction.

27. An article comprising the fabric of any of claims 1-26.

28. The article of claim 27, which is a glove.

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