JP2013540915A - Arc-resistant garment containing multilayer fabric laminate and method of making the same - Google Patents

Abstract

  The present invention relates to a protective garment and a method of making such a garment, the garment having use in an environment where electric arcing is possible, the garment comprising a first layer of flame resistant woven fabric. (Comprising a first flame retardant fiber that forms the outer surface of the garment and made from a synthetic polymer comprising halogen) and a second layer of flame resistant woven fabric (a second made from a synthetic polymer). The first flame retardant fiber has a pyrolysis temperature that is at least 70 ° C. lower than the second flame retardant fiber. And the fabrics in the first and second layers are different, and the first layer is positioned on the garment so that it is closer to the potential electric arc environment than the second layer.

Description

  The present invention relates to a multilayer fabric laminate having improved arc performance and a protective garment containing the multilayer fabric laminate.

  US Pat. No. 7,065,950 and US Pat. No. 7,348,059 (assigned to Zhu et al.) Describe a blend of modacrylic / aramid fibers for use in arc and flame protection fabrics and garments. Disclose. Arc resistant garments are used in situations where life can be at risk. Thus, any garment structure that can provide improved arc protection can reduce the chance of injury and potentially save lives.

  The present invention relates to a protective garment having use in an environment where electric arc is possible, the garment comprising a first layer of flame resistant woven fabric (from a synthetic polymer which forms the outer surface of the garment and comprises halogen). Arc-resistant multilayer comprising a first flame-retardant fiber made) and a second layer of flame-resistant woven fabric (comprising a second flame-retardant fiber made from a synthetic polymer) The first flame retardant fiber has a pyrolysis temperature that is at least 70 ° C. lower than the second flame retardant fiber, and the fabrics in the first layer and the second layer are different from each other. The layer is positioned on the garment so that it is closer to a potential electric arc environment than the second layer.

The present invention also relates to a method of making a protective garment having use in an environment where electric arc is possible,
i) providing a first flame resistant woven fabric comprising a first flame retardant fiber made from a synthetic polymer comprising a halogen;
ii) providing a second flame resistant woven fabric comprising a second flame retardant fiber made from a synthetic polymer, wherein the first flame retardant fiber is at least 70 than the second flame retardant fiber. The first flame resistant woven fabric and the second flame resistant woven fabric have different pyrolysis temperatures, and different processes;
iii) a step of combining the first flame resistant woven fabric and the second flame resistant woven fabric to form an arc resistant multilayer fabric laminate, wherein the first flame resistant woven fabric and the second flame resistant woven fabric are: A separate fabric layer with no shared weft or warp yarns, and
iv) A process for forming an arc resistant garment from an arc resistant multi-layer fabric laminate, wherein the first flame resistant woven fabric forms the outer surface of the garment and is more likely to be an electric arc than the second layer. Positioning the garment closer to a certain environment.

2 is an atmospheric thermogravimetric scan illustrating how the pyrolysis temperature of a fiber can be measured. 2 is an atmospheric thermogravimetric scan illustrating how the pyrolysis temperature of a fiber can be measured.

  The present invention relates to protective garments having use in environments where electrical arcing is possible. A potential electric arc environment means any situation in which an operator may be exposed to an electric arc that can cause injury or death.

  The present invention relates to a protective garment having an arc-resistant multilayer fabric laminate comprising at least two flame-resistant fabric layers having different compositions. The first flame resistant fabric layer comprises a first flame retardant fiber that forms the outer surface of the garment and contains a synthetic polymer comprising a halogen. The second flame resistant fabric layer comprises a second flame retardant fiber containing a synthetic polymer. Further, the first flame retardant fiber and the second flame retardant fiber have different compositions, and the first flame retardant fiber is pyrolyzed at least 70 ° C. lower than the pyrolysis temperature of the second flame retardant fiber. Have temperature.

  The different fabric compositions provide a directional multi-layer fabric laminate, wherein the multi-layer fabric laminate is in an environment where the first flame resistant fabric layer is more likely to be an electric arc than the second flame resistant fabric layer. It is positioned in the clothing so that it is close.

  This type of protective clothing includes protective coats, jackets, jumps used by professional workers (eg, electricians, process control professionals, and other professionals who may work in an electric arcing environment). Suits, coveralls, hoods and the like. In a preferred embodiment, the protective garment is a coat or jacket (including a three-quarter-length coat typically used on the garment and other protective equipment required for electrical panel or substation work).

  In a preferred embodiment, the protective garment has an arc rating of at least category 2 or greater as measured by either of two types of category grading systems commonly used for arc ratings. The National Fire Protection Association (NFPA) has four different categories, with category 1 having the lowest performance and category 4 having the highest performance. Based on the NFPA 70E system, categories 1, 2, 3, and 4 correspond to heat fluxes through the fabric of 4, 8, 25, and 40 calories / square centimeter, respectively. The National Electric Safety Code (NESC) also has a system that ranks into three different categories, with Category 1 having the lowest performance and Category 3 having the highest performance. Based on the NESC scheme, categories 1, 2, and 3 correspond to heat fluxes through the fabric of 4, 8, and 12 calories / square centimeter, respectively. Thus, a fabric or garment having a category 2 arc rating can withstand a heat flux of 8 calories / square centimeter as measured by a series of standard methods ASTM F1959 or NFPA 70E.

  An electric arc typically involves a current of thousands of volts and thousands of amperes, exposing the garment to strong incident energy. In order to protect the wearer, the garment must prevent this incident energy from being transferred to the wearer. This is most likely to occur when the outer fabric suppresses so-called “break open” while absorbing some of the incident energy. Holes are formed in the fabric during "break open". Accordingly, arc protective garments are designed to avoid or minimize the breaking open of any fabric layer in the garment.

  It has now been found that improved arc performance can be achieved by using a multilayer fabric laminate having at least two flame resistant fabric layers, and when exposed to an arc, a fabric layer that is closer to an electric arc It actually acts as a sacrificial material and opens a break. It is believed that disassembly of the outer fabric provides an energy sink that reduces energy transfer through the multilayer fabric laminate.

  The multilayer fabric laminate includes at least one layer of a first flame resistant fabric and at least one layer of a second flame resistant fabric. In some embodiments, the first flame resistant fabric layer has a basis weight of about 5-9 ounces / square yard and the second flame resistant fabric layer has a basis weight of about 4-8 ounces / square yard. Have. In some embodiments, the first flame resistant fabric layer has a basis weight of about 6.5 to 9 ounces per square yard. In some embodiments, the second flame resistant fabric layer has a basis weight of about 4.5 to 7.5 ounces per square yard. In some embodiments, a multi-layer fabric laminate can include two adjacent layers of a first flame resistant fabric and a layer of a second flame resistant fabric. In some embodiments, the multi-layer fabric laminate can include a layer of a first flame resistant fabric and an adjacent two layers of a second flame resistant fabric. In some other embodiments, a multilayer fabric laminate can include two adjacent first flame resistant fabrics and two adjacent second flame resistant fabrics.

  A flame resistant fabric means that one layer of the fabric has a longitudinal carbonization length of 6 inches or more during testing. Carbonization length is a measure of the flame resistance of a textile fiber. Carbonization is defined as a carbonaceous residue formed as a result of pyrolysis or incomplete combustion. The char length of a fabric under ASTM 6413-99 test conditions is defined as the distance from the end of the fabric directly exposed to the flame to the furthest point of fabric damage visible after applying a specified tear force. The

  Flame retardant fiber means that a fiber or fabric made solely from flame retardant fiber will not support a flame, and that fiber or fabric, as measured by ASTM G-125-00, It means having a limiting oxygen index (LOI) greater than the atmospheric oxygen concentration (ie greater than 21 and preferably greater than 25).

  The term “fabric” refers to a single layer structure that is assembled by weaving warp yarn and weft yarn in a conventional manner on a weaving machine. One preferred embodiment is twill, but plain or satin weave may be used. “Yarn” refers to a collection of fibers spun or twisted together to form a continuous strand that can be used in weaving, knitting, or otherwise made into fiber materials or fabrics. Means. The yarn can be a staple fiber yarn. Staple fiber yarns include yarn spinning techniques (e.g., ring spinning, core spinning, and air spinning including air spinning techniques such as Murata air spinning, which uses air to twist staple fibers) But not limited to these). If single yarns are produced, then they are preferably twisted to form a twisted yarn comprising at least two single yarns before being converted to a fabric. Alternatively, fabrics can be made using multifilament continuous filament yarns, or a combination of multifilament and staple fiber yarns can be used.

  The first flame retardant fiber is present in the woven fabric of the first flame resistant fabric layer in an amount of at least 20% by weight and is usually present in the yarn of the fabric. The first flame retardant fiber contains a synthetic polymer comprising halogen, and is preferably made exclusively from a synthetic polymer comprising halogen. One useful halogen is chlorine, although other halogens can be used.

  In some embodiments, the first flame resistant fabric contains a blend of yarns, or the yarns contain a blend of fibers comprising modacrylic, meta-aramid, and para-aramid fibers. Further, a small amount of antistatic fiber may be contained. In one embodiment, the yarn blend or fiber blend comprises 20-70 wt% modacrylic fiber, 11-64 wt% meta-aramid fiber, 5-15 wt% para-aramid fiber, and 0.5 to 4% by weight of antistatic fibers may be included. If desired, FR rayon, cotton, or wool may be substituted for part of the modacrylic fiber as long as at least 20% of the halogen-containing fiber remains in the first flame resistant fabric. In general, this means that, if desired, these substituted fibers can be present in an amount up to about 50% of the blend.

  In one preferred embodiment, the first flame resistant fabric contains a blend of yarns, or the yarns are 40-70% by weight modacrylic fiber, 15-55% by weight meta-aramid fiber, and 5-15. It contains a homogeneous blend of fibers comprising weight percent para-aramid fibers and may contain 0.5 to 3 weight percent antistatic fibers. In some embodiments, a blend of yarns or a homogenous blend of fibers comprises 55-70% by weight modacrylic fiber, 20-40% by weight meta-aramid fiber (meta-aramid is poly (metaphenylene isophthalamide). 5) -10% by weight of para-aramid fiber (para-aramid is poly (paraphenylene terephthalamide)), and 2-3% by weight of carbon core / polyamide sheath antistatic fiber Become. In some embodiments, the first flame resistant fabric contains a blend of yarns, or the yarns are fiber blends consisting essentially of modacrylic fibers, meta-aramid fibers, and para-aramid fibers. And may contain a small amount of antistatic fiber in the amount described above. All percentages described herein are based on the specified ingredients, ie, the total weight of the specified ingredients in the yarn or fiber blend.

  The second flame retardant fiber is present in the woven fabric of the second flame resistant fabric layer and is usually present in the yarn of the fabric. Useful flame retardant fibers include aramid fibers, polybibenzimidazole fibers, or polybenzoazole fibers, or blends of any of these fibers. In a preferred embodiment, the second flame resistant fabric layer contains at least 70% by weight of the above fibers, and the preferred fibers are meta-aramid fibers. In some preferred embodiments, the yarn has at least 75% by weight of meta-aramid fibers. In some embodiments, a suitable maximum amount of meta-aramid fibers is 93 wt% or less, but amounts as high as 100 wt% can be used.

  In some embodiments, the second flame resistant fabric contains a blend of yarns, or the yarn contains a blend of fibers comprising meta-aramid fibers and para-aramid fibers, and a small amount. The antistatic fiber may be contained. One embodiment of this yarn or fiber blend comprises 70-93 wt% meta-aramid fibers and 7-30 wt% para-aramid fibers. The yarn blend or fiber blend may also contain 0.5 to 3% by weight of antistatic fibers. In some preferred embodiments, the yarn blend or fiber blend is 85 to 93 wt% meta-aramid fiber (meta-aramid is poly (metaphenyleneisophthalamide)), and 7 to 15 wt% Of para-aramid fibers (para-aramid is poly (paraphenylene terephthalamide)) and may contain 2-3 wt% carbon core / polyamide sheath antistatic fibers. By adding a small amount of rigid rod or para-aramid fibers to the yarn, the fabric with high content of meta-aramid fibers or other fabrics that have unacceptable flame shrinkage will be resistant to flame shrinkage. Can provide some additional resistance.

  In a preferred embodiment, the second flame resistant fabric contains a blend of yarns, or the yarn contains a homogeneous blend comprising meta-aramid and para-aramid fibers, and a small amount of charge. You may contain prevention fiber. In some embodiments, the second flame resistant fabric contains a blend of yarns, or the yarn contains an intimate blend of fibers consisting essentially of para-aramid and meta-aramid fibers. In addition, a small amount of the antistatic fiber in the amount described above may be contained. All percentages described herein are based on the specified ingredients, ie, the total weight of the specified ingredients in the yarn or fiber blend.

  An antistatic ingredient is an optional ingredient in clothing and is used in these situations that can be dangerous for workers, such as when working with electrical equipment where electrostatic discharge is susceptible to damage or when working near flammable vapors. Can be done. In one embodiment, the antistatic component is present as a fiber in at least some of the yarns in the garment fabric. Specific examples include steel fibers, carbon fibers, or existing fibers incorporating carbon, and can be present in the garment fabric in an amount of 0.5-5% by weight. In some embodiments, the antistatic component is present in the garment fabric in an amount of only 2-3% by weight. US Pat. No. 4,612,150 (assigned to De Howitt) and US Pat. No. 3,803,453 (assigned to Hull) describe particularly useful conductive fibers, where carbon black is thermoplastic. Conductance is provided that is dispersed within the fibers to prevent the fibers from being antistatic. A suitable antistatic fiber is a carbon core / nylon sheath fiber. The use of antistatic fibers provides yarns, fabrics and garments with reduced chargeability, thus reducing the apparent field strength and annoying static electricity.

  In some embodiments, only yarns having the above ratio of the first flame retardant fiber, the second flame retardant fiber and any other fibers and / or antistatic fibers are present in the fabric. In the case of woven fabrics, these yarns are preferably used for both warp and weft yarns of the fabric. If desired, the relative amounts of the first flame retardant fiber and the second flame retardant fiber, and the antistatic fiber described above, vary between the warp and the weft as long as the composition of both yarns is within the above range. It is also possible.

  In one embodiment, both multi-layer fabric laminates, the yarns used to make the first and second flame resistant fabrics, and the fabric itself consist essentially of the fibers described above in the stated proportions. Except for a small amount of antistatic fiber, it does not contain any other additional thermoplastic or flammable fibers or materials. Other materials and fibers (eg, polyamide or polyester fibers, etc.) are believed to provide flammable materials for yarns, fabrics, and garments and affect the protective performance of the garments.

In an environment where additional thermal protection is desired, 1-4 layers of a thin flame resistant insulation fabric is sandwiched between a first flame resistant fabric and a second flame resistant fabric, and a multilayer fabric laminate as defined herein. It can be part of As such a heat insulating nonwoven fabric, it is formed from a lightweight (0.5 to 3.0 oz / yd ² ) needle punched nonwoven fabric, a hydroentangled nonwoven fabric, or a card processing, air raid, or wet laid cut fiber web by another method. The consolidated non-woven fabric can be mentioned. Such a fabric preferably has a basis weight of 1-2 oz / yd ² . A fabric containing flame retardant fibers is particularly suitable. A suitable flame resistant fabric is Nomex® E89, a spunlace nonwoven material made from a blend of meta-aramid staple fibers and para-aramid staple fibers, and E.I., Wilmington, Delaware. I. Available from du Pont de Nemours & Company. The E89 fabric has a nominal thickness of 19 mils (0.48 mm) and a basis weight of 1.5 oz / yd ² (50.5 g / m ² ). In one preferred embodiment, all layers of the fabric within the multilayer fabric laminate are stitched only at the edges and / or on the garment, allowing for maximum flexibility of the fabric layers within the multilayer fabric laminate. Join together.

  In some embodiments, the multi-layer fabric laminate has a total basis weight of 11 to 25 ounces per square yard. In some preferred embodiments, the total basis weight of the multilayer fabric laminate is 11 to 20 ounces per square yard.

  In some preferred embodiments, the multilayer fabric laminate is normalized to basis weight of at least 2.0 calories / square centimeter / ounce / square yard (0.247 joules / square centimeter / gram / square meter). Has an arc resistance. In some embodiments, the arc resistance normalized to basis weight is preferably at least 2.2 calories / square centimeter / ounce / square yard (0.272 joules / square centimeter / gram / square meter).

  One fiber useful as the first flame retardant fiber is modacrylic fiber. Modacrylic fiber means an acrylic synthetic fiber made mainly from a polymer comprising acrylonitrile. This polymer is preferably a copolymer comprising 30 to 70% by weight of acrylonitrile and 70 to 30% by weight of a halogen-containing vinyl monomer. The halogen-containing vinyl monomer is, for example, at least one monomer selected from vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide and the like. Examples of copolymerizable vinyl monomers are acrylic acid, methacrylic acid, salts or esters of such acids, acrylamide, methyl acrylamide, vinyl acetate and the like.

  A suitable modacrylic fiber is a copolymer of acrylonitrile and vinylidene chloride, the copolymer further having one or more antimony oxides to improve flame retardancy. As such useful modacrylic fibers, the fibers disclosed in U.S. Pat. No. 3,193,602 having 2 wt% antimony trioxide, an amount of at least 2 wt%, preferably no more than 8 wt% US Pat. No. 5,208, having fibers disclosed in US Pat. No. 3,748,302, and 8-40 wt% antimony compound, made with various antimony oxides present in , 105 and U.S. Pat. No. 5,506,042 (but not limited to). Among the yarns, modacrylic fibers provide flame retardant carbonized fibers with a LOI typically at least 28, depending on the amount of antimony derivative added.

  In addition, other fibers can be present in the first flame retardant fabric layer, including aramid fibers, flame retardant rayon fibers, cotton fibers, wool fibers, and mixtures of these fibers. Can be mentioned. These are usually either in the form of a mixture with, for example, modacrylic fibers, or as separate threads with only one fiber, or as separate threads with a mixture of various fibers, usually Present in the yarn of the fabric.

  As used herein, “aramid” refers to a polyamide in which at least 85% of the amide (—CONH—) linkages are directly attached to two aromatic rings. Additives can be used with aramids, in fact up to 10% by weight of other polymeric materials can be blended with aramids, or copolymers with as many as 10% other diamines instead of aramid diamines Alternatively, it has been found that copolymers having as many as 10% other diacid chlorides can be used in place of the aramid diacid chloride. Suitable aramid fibers are described in “Man-Made Fibers--Science and Technology”, Volume 2, entitled “Fiber-Forming Aromatic Polymers”, p. 297, W.H. Black et al., Interscience Publishers, 1968. Aramid fibers are disclosed in U.S. Pat. No. 4,172,938, U.S. Pat. No. 3,869,429, U.S. Pat. No. 3,819,587, U.S. Pat. No. 3,673,143. , U.S. Pat. No. 3,354,127, and U.S. Pat. No. 3,094,511. Meta-aramid is an aramid in which the amide bonds are in the meta position relative to each other, and para-aramid is an aramid in which the amide bonds are in the para position relative to each other. Examples of meta-aramid include poly (metaphenylene isophthalamide), and examples of para-aramid include poly (paraphenylene terephthalamide). Among the yarns, meta-aramid fibers typically provide para-aramid fibers having a LOI of at least about 27 to flame retardant fibers having a LOI of at least about 25.

  In some embodiments, the meta-aramid fiber has a minimum crystallinity of at least 20%, more preferably at least 25%. For illustrative purposes to facilitate final fiber formation, a practical upper limit of crystallinity is 50% (however, a higher percentage is considered appropriate). Generally, the crystallinity will be in the range of 25-40%. Examples of commercially available meta-aramid fibers having this degree of crystallinity include E.I., Wilmington, Delaware. I. Nomex® T450 available from du Pont de Nemours & Company.

  The crystallinity of the meta-aramid fiber can be measured by one of two methods. The first method is used for fibers that are completely free of voids, and the second method is used for fibers that are not completely free of voids.

The crystallinity (%) of meta-aramid in the first method is determined by first generating a linear calibration curve for crystallinity using a good essentially void-free sample. For samples with no such voids, the specific volume (1 / density) can be directly related to crystallinity using a two-phase model. The density of the sample is measured with a density gradient tube. A meta-aramid film determined to be amorphous by x-ray diffraction was measured and found to have an average density of 1.3356 g / cm ³ . The density of the fully crystalline meta-aramid sample was then determined from the x-ray unit cell dimensions and determined to be 1.4699 g / cm ³ . Once these 0% and 100% crystallinity endpoints have been established, the crystallinity of an experimental sample with no voids of known density can be determined from this linear relationship.

式中、ｌ（１６５０ｃｍ^-1）は、その点でのメタ−アラミド試料のラマン強度である。この強度を用いて、実験試料の結晶化度（％）を式から計算する。 Many fiber samples are not free of voids at all, so Raman spectroscopy is a preferred method for determining crystallinity. Since the Raman measurement is not affected by the amount of voids, the crystallinity of any form of meta-aramid is measured using the relative strength of carbonyl group stretching at 1650-1 cm, regardless of the presence or absence of voids. be able to. To achieve this, the linear relationship between crystallinity and the stretching strength of the carbonyl group at 1650 cm −1 (normalized to the strength of the ring stretching mode at 1002 cm −1) It was constructed using a sample (the crystallinity of the sample is predetermined and known from the above density measurements). Using the Nicolet model 910 FT-Raman spectrometer (Raman Spectrometer), the following empirical relationship depending on the density calibration curve was constructed in terms of crystallinity (%).

Where l (1650 cm ⁻¹ ) is the Raman intensity of the meta-aramid sample at that point. Using this intensity, the crystallinity (%) of the experimental sample is calculated from the equation.

  Meta-aramid fibers are only spun out of solution, cooled, built with very low crystallinity when dried using temperatures below the glass transition temperature without additional heating or chemical treatment. . Such fibers have a crystallinity (%) of less than 15% when the fiber crystallinity is measured using the Raman scattering method. These fibers with low crystallinity are considered amorphous meta-aramid fibers that can be crystallized through heating or chemical means. Crystallinity can be increased by heat treatment at or above the glass transition temperature of the polymer. Such heat is typically applied by contacting the fiber with a heated roll under tension for a time sufficient to impart the desired amount of crystallinity to the fiber.

  The crystallinity of m-aramid fibers can be increased by chemical treatment, and in some embodiments this includes methods of coloring, dyeing, or pre-dying the fibers prior to incorporation into the fabric. Several methods are described, for example, in US Pat. No. 4,668,234, US Pat. No. 4,755,335, US Pat. No. 4,883,496, and US Pat. No. 096,459. Dyeing aids known as dye carriers may be used to increase dyeing of aramid fibers. Useful dye carriers include aryl ethers, benzyl alcohol, or acetophenone.

  By flame retardant rayon fiber is meant rayon fiber having one or more flame retardants and having a fiber tensile strength of at least 2 grams / denier. Cellulose or rayon fibers containing silicon dioxide as a flame retardant in the form of polysilicic acid have a low fiber tensile strength, so such fibers are specifically removed. In addition, while such fibers are good carbon formers, relative to their performance, their vertical combustion performance is inferior to fibers containing phosphorus compounds or other flame retardants.

  Rayon fibers are known in the art and are generally man-made fibers made of regenerated cellulose and further have regenerated cellulose where the substituents are substituted for up to 15% of the hydroxyl group hydrogens. They include yarns made by the viscose method, the copper ammonia method, and the now obsolete nitrocellulose and saponified acetate methods, but in a preferred embodiment, the viscose method is used. Generally, rayon is obtained from wood pulp, cotton linter, or other plant matter dissolved in a viscose spinning solution. The solution is extruded into an acid-salt coagulation bath and drawn into continuous filaments. These groups of filaments may be formed into yarns or cut into staples and further processed into staple spun yarns. Examples of the rayon fibers used in the present specification include fibers known as lyocell fibers.

  A flame retardant chemical substance is added to the spinning solution, the flame retardant substance is spun into rayon fiber, the rayon fiber is coated with the flame retardant substance, and the rayon fiber is brought into contact with the flame retardant substance. The flame retardant can be incorporated into the rayon fiber by absorbing the flame retardant material or by any other method of incorporating the flame retardant into or mixing with the rayon fiber. In general, rayon fibers containing one or more flame retardants are given the name “FR” meaning flame retardants. In a preferred embodiment, the FR rayon has a flame retardant incorporated by spinning.

  FR rayon has a high moisture content, which provides a comfort element to the fabric. It is believed that the yarn should have at least 10% by weight FR rayon to provide the fabric with appreciable comfort. In addition, higher FR rayon proportions may provide even more comfort, but if the amount of FR rayon exceeds about 30% in the yarn, the fabric may negate any comfort improvement. There is a possibility of having a problem that adversely affects performance. In some preferred embodiments, the FR rayon fibers are present in the yarn in an amount of 15-25% by weight.

  The FR rayon fibers can contain one or more various commercially available flame retardants including specific phosphorus compounds such as, for example, Sandolast 9000® available from Sandoz. Although various compounds can be used as a flame retardant, in a preferred embodiment, the flame retardant is based on a phosphorus compound. Useful FR rayon fibers are available from Daiwabo Rayon Co., Ltd., Japan, under the name DFG “Flame-retardant viscose rayon”. Another useful FR rayon fiber is available from Lenzing AG under the name Viscose FR (also known as Lenzing FR® available from Lenzing Fibers, Austria).

  Cotton fiber is a well-known natural fiber made of almost pure natural cellulose. As obtained from plants, cotton fibers have a fiber length of about 0.375 to 2 inches. Wool fiber refers to the well-known natural fiber, usually sheep, lamb, or Angora or Cashmere goat fleece. The name can also be used for hair from camels, alpaca, llamas and / or vicuna.

  Polybibenzimidizole fiber (PBI) is polybibenzimidazole as made by the methods disclosed in US Pat. No. 2,895,948 and US Reissue Pat. No. 26,065. It means a fiber comprising a polymer. Polybibenzimidazole fibers can be made by known methods such as those disclosed in US Pat. No. 3,441,640 and US Pat. No. 4,263,245. One useful polybibenzimidazole polymer is a poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole) polymer. One commercially available PBI polymer is prepared from tetra-aminobiphenyl and diphenylisophthalate.

  By polybenzoazole fiber is meant a fiber containing homopolymers and copolymers of polybenzoxazole (PBO), polybenzothiazole (PBT), and polybenzimidazole having a LOI greater than 21. Suitable polybenzoazole homopolymers and copolymers are described in US Pat. No. 4,533,693 (to Wolfe et al., Aug. 6, 1985), US Pat. No. 4,703,103 (1987). Granted to Wolfe et al. On Oct. 27, 1992, U.S. Pat. No. 5,089,591 (granted to Gregory et al. On Feb. 18, 1992), U.S. Pat. No. 4,772,678 (1988). Granted to Sybert et al. On Sep. 20, 1992), U.S. Pat. No. 4,847,350 (granted to Harris et al. On Aug. 11, 1992), and U.S. Pat. No. 5,276,128 ( It can be prepared by a known procedure such as the procedure described in Rosenberg et al. On Jan. 4, 1994). Polybenzoimidazole also includes polybenzobisimidazole, polybenzothiazole also includes polybenzobisthiazole, and polybenzoxazole includes polybenzobisoxazole.

  The first flame retardant fiber of the first flame resistant fabric has a thermal decomposition temperature that is at least 70 ° C. lower than the thermal decomposition temperature of the second flame resistant fabric of the second flame resistant fabric. As used herein, the “pyrolysis temperature” of a fiber is the first major decomposition temperature measured in the atmosphere by Thermogravimetric Analysis (TGA) and is a modified weight loss of TGA analysis. loss) (% weight loss / ° C.) defined as the temperature at the starting point measured using a scan. The starting point is measured using the TA Systems Universal Analysis software program. The start point is defined as the extrapolation start point of any transition determined by data analysis. Alternatively, this can be shown schematically. The starting point is the first large differential peak or shoulder 1 in the differential weight scan, as shown in FIG. 1 (with a scan representing the modacrylic fiber of one embodiment) and the above in the modified weight scan. It is determined by drawing tangent lines 2 and 3 corresponding to the peaks. The intersection of these two tangents provides point 4, which is the first major pyrolysis temperature as defined herein. Similarly, as defined herein, the initial major pyrolysis temperature of one embodiment of Nomex® meta-aramid fiber is shown by the scan displayed in FIG. Using the first large differential peak or shoulder 5 in the differential weight scan, tangents 6 and 7 corresponding to the above peaks are drawn on the modified weight scan, and the intersection of these two tangents is the first at point 8. Provides the main pyrolysis temperature. TGA measurements were performed on a TA Systems Q500 TGA under default Hi Res conditions (sensitivity 1.0 / resolution 4.0). In order to eliminate the influence of moisture in the analysis, the 100% Y axis is set at 150 ° C. As measured by this method, modacrylic has a pyrolysis temperature where modacrylic is about 225-275 ° C., while metaphenylene isopthalamide is about 400-475 ° C. The first large differential peak or shoulder is the differential weight deviation from the 0.0 baseline of at least 20%.

In one embodiment, the present invention also relates to a method of making a protective garment having use in an environment where electric arc is possible,
i) providing a first flame resistant woven fabric comprising a first flame retardant fiber made from a synthetic polymer comprising a halogen;
ii) providing a second flame resistant woven fabric comprising a second flame retardant fiber made from a synthetic polymer, wherein the first flame retardant fiber is at least 70 ° C lower than the second flame retardant fiber Having a pyrolysis temperature, the first flame resistant woven fabric and the second flame resistant woven fabric are different steps;
iii) a step of combining the first flame resistant woven fabric and the second flame resistant woven fabric to form an arc resistant multilayer fabric laminate, wherein the first flame resistant woven fabric and the second flame resistant woven fabric are: A separate fabric layer having no shared weft or warp yarns, and
iv) A process for forming an arc resistant garment from an arc resistant multi-layer fabric laminate, wherein the first flame resistant woven fabric forms the outer surface of the garment and is more likely to be an electric arc than the second layer. Positioning the garment closer to a certain environment.

  The first woven fabric and the second woven fabric include actually manufacturing individual yarns using the above-described fibers in various ratios described above, and then weaving the above-described fabrics from these yarns. It can be provided in a variety of different ways.

  In a preferred embodiment, the individual yarns are made from a homogeneous blend of staple fibers. “Homogeneous blend” means that the various staple fibers in the composition form a relatively uniform mixture. If desired, other staple fibers can be incorporated into this relatively uniform mixture of staple fibers. Blending can be accomplished by a number of methods known in the art, in which multiple bobbins of continuous filaments are creeled and simultaneously cut two or more types of filaments. A method of forming a blend of chopped staple fibers, or a method involving opening and blending various fibers with an opener, blender, and card after unpacking a bale of different staple fibers, Alternatively, a method of forming a sliver of a mixture of various staple fibers and then further processing it to form a mixture, such as in a card forming a sliver of a mixture of fibers, is included. Other methods of making a homogeneous fiber blend are possible as long as the various types of different fibers are distributed relatively uniformly throughout the blend. Yarns formed from blends have a relatively uniform mixing of staple fibers as well. In general, in the most preferred embodiment, the individual staple fibers are not present in an amount such that fiber knots or slabs and other large defects due to poor fiber opening of the staple fibers impair the quality of the final fabric. It is opened or separated to a standard degree in fiber processing to make useful fabrics. As previously described herein, the yarns are combined and woven together on a conventional weaving machine to form a single layer woven structure of the first or second woven fabric in a preferred embodiment. The glige fabric can be completed as desired.

  The first flame resistant woven fabric and the second flame resistant woven fabric can be combined to form an arc resistant multilayer fabric laminate. One convenient way of forming a multilayer fabric laminate is to provide a layer of one fabric on a flat surface such as a cutting table and then cover the fabric with a layer of the other fabric. If desired, multiple layers of either the first flame resistant woven fabric or the second flame resistant woven fabric can be used in the multilayer fabric laminate, or one or more layers of flame resistant thermal insulation fabric (eg, A layer of flame resistant insulation fabric, etc. already described herein) is laid between the first flame resistant fabric and the second flame resistant fabric as long as they do not impair the final garment or the desired properties of the garment. Or can be inserted.

  Since the first flame resistant woven fabric will ultimately form the outer surface of the final garment, the first flame resistant woven fabric is combined to form a multilayer fabric laminate, the first flame resistant woven fabric being a multilayer Care should be taken when forming the outer surface of the fabric laminate. In some embodiments, the second flame resistant woven fabric forms the opposite outer surface of the multilayer fabric laminate. However, in some other embodiments, the opposite outer surface of the multilayer fabric laminate may be another fabric. For example, the opposite outer surface may be a soft fabric that will eventually become the inner lining of the protective garment. This is because the surface of this multilayer fabric laminate is closer to the wearer inside the garment.

  The first flame resistant fabric and the second flame resistant fabric are combined as separate and distinct fabric layers (ie, there are no shared warp or weft yarns that can weaken either layer). Thereby, the first flame resistant woven fabric is completely a sacrificial layer and the second flame resistant woven fabric is completely a thermal protection layer. In addition, this provides a space to provide an additional fabric layer between the first flame resistant fabric and the second flame resistant fabric, if desired.

  Arc resistant garments are made from arc resistant multilayer fabric laminates. The first flame resistant woven fabric forms the outer surface of the garment and is positioned within the garment that is closer to an environment that may have an electric arc than the second flame resistant woven fabric layer when worn.

  The garment can be formed in a number of ways. For example, after forming the above-mentioned multi-layered cloth laminate on a cutting table, the laminate is produced in protective patterns (eg, coats, jackets, coveralls, jumpsuits, hoods, etc.) for each predetermined pattern. It can be cut into a suitable fabric shape. Alternatively, such fabric shapes are obtained by forming a multilayer fabric laminate from individually cut fabric shapes and laying up each layer of the fabric described above. The shape of the multilayer fabric laminate is stitched with the first flame resistant fabric of the multilayer fabric laminate (which is the outer surface of the garment in use) that forms the outer surface of the final garment to form the desired garment. By doing so, the first flame resistant woven fabric is positioned in the garment closer to the potential electric arc environment than the second flame resistant woven layer.

Test Method Default conditions (sensitivity 1 / resolution) at an equilibrium gas purge flow of 60 ml / min and a sample gas purge flow of 40 ml / min under TA Systems Hi-Res® in the atmosphere of TA Instrument Q500 TGA at 40-1000 ° C. In 4), thermogravimetric analysis (TGA) was performed in the atmosphere using ASTM E1131-08.

  The arc resistance of the fabric is measured according to ASTM F-1959-99 “Standard Test Method for Determining the Arc Thermal Performance Value of Materials for Closing”. The Arc Thermal Performance Value (ATPV) of each fabric can be subject to exposure that a person wearing the fabric is equivalent to two burns at such exposure for 50% of the time. It is a measure of energy.

  The fabric's limiting oxygen index (LOI) is measured at room temperature according to ASTM G-125-00 “Standard Test Method for Measuring Liquid and Solid Material Fire Limits in Gas Oxidants”.

  The carbonization length of the fabric is measured according to ASTM D-6413-99 “Standard Test Method for Flame Resistance of Textiles” (Vertical Methods).

  Basis weight was obtained based on FTMS 191A; 5041.

  Fabrics used in the following examples were prepared as follows. Fabric 1 was woven with air spun yarns made from a homogeneous blend of Nomex® type 455 fiber, Kevlar® 29 fiber, and P140 fiber. Nomex® type 455 fiber is non-crystallized poly (m-phenylene isophthalamide) (MPD-I) staple fiber, and Kevlar® 29 fiber is poly (p-phenylene terephthalamide) (PPD- T) Staple fibers and P140 fibers are antistatic staple fibers having a carbon core and a nylon sheath.

  After preparing a sliver blended with a cotton machine with 93 weight percent Nomex® type 455 fiber, 5 weight percent Kevlar® 29 fiber, and 2 weight percent P140 fiber, conventional cotton spinning It was processed into a spun yarn using a system processing and an air spinning machine. The spun yarn so produced was a 15.5 tex (38 cotton count) single yarn. Thereafter, these two single yarns were twisted with a twisting machine to produce a double yarn having a twist number of 12 times / inch.

Double yarn was used for both warp and weft on a shuttle loom to form a plain weave fabric. The gray fabric had a basis weight of 136 g / m ² (4.0 oz / yd ² ). The glige fabric was washed with hot water and then liquid dyed with a basic dye. The basis weight of the finished fabric was nominally 153 g / m ² (4.5 oz / yd ² ).

Fabric 2 was produced in the same manner as Fabric 1, except that the spun yarn was 12.2 tex (30 cotton count) single yarn. Next, as in the case of the fabric 1, two single yarns were twisted with a twisting machine to produce a double yarn having a twist number of 12 times / inch. The resulting gray fabric had a basis weight of 186 g / m ² (5.5 oz / yd ² ). The glige fabric was washed with hot water and then liquid dyed with a basic dye. The basis weight of the finished fabric was nominally 203 g / m ² (6.0 oz / yd ² ).

Fabric 3 was woven with air spun yarn made from a homogeneous blend of Protex® C fiber, Nomex® type 450 fiber, Kevlar® 29 fiber, and P140 fiber. Protex® C fiber is a modacrylic staple fiber of ACN / polyvinylidene chloride copolymer with up to 10% antimony, and Nomex® type 450 fiber is crystallized poly (m-phenyleneisophthalamide) ( MPD-I) staple fibers, and Kevlar® 29 fibers and P140 fibers are similar to fabrics 1 and 2. Blended in a cotton machine with 65% by weight Protex® C fiber, 23% by weight Nomex® type 450 fiber, 10% by weight Kevlar® 29 fiber, and 2% by weight antistatic fiber After the sliver was struck, it was processed into a spun yarn by the same method as for Fabric 1. The spun yarn so produced was a 21 tex (28 cotton count) single yarn. Thereafter, these two single yarns were twisted with a twisting machine to produce a double yarn having a twist number of 10 times / inch. Next, a twin yarn was used for both warp and weft on a shuttle loom to form a 2 × 1 twill fabric having a structure of length 31 × width 16 / cm (length 77 × width 47 / inch). The twill fabric had a basis weight of 203.4 g / m ² (6.0 oz / yd ² ). The glige fabric was washed with hot water and then liquid dyed with a basic dye. The basis weight of the finished twill fabric was nominally 220.3 g / m ² (6.5 oz / yd ² ).

Fabric 4 was produced in the same manner as Fabric 3, except that the twill fabric had a structure of length 31 × width 28 / cm (length 77 × width 70 / inch). The gray fabric had a basis weight of 254 g / m ² (7.5 oz / yd ² ). After washing and dyeing, the fabric had a nominal basis weight of 271 g / m ² (8.0 oz / yd ² ).

Comparative Example A
The fabric 1 was overlapped on the fabric 3 to form a multilayer fabric laminate. In order to simulate the electric arc performance of the garment containing the laminate, the fabric 1 is positioned near the arcing point and the fabric 3 is positioned near the virtual wearer of the garment. Positioned in the arc testing machine. This simulates a garment having fabric 1 as the outer layer and fabric 3 as the inner layer. The arc rating of this multilayer fabric laminate was measured and shown in the table.

Example 1
Fabric 3 was positioned near the point of arc occurrence and fabric 1 was positioned near the virtual wearer of the garment, and the position of the multilayer fabric laminate of Comparative Example A was reversed in the arc tester. This simulates a garment having fabric 3 as the outer layer and fabric 1 as the inner layer. The arc rating of this laminate was measured and shown in the table.

Comparative Example B
Comparative Example A was repeated except that fabric 3 was replaced with heavier fabric 4. The arc rating of this laminate was measured and shown in the table.

Comparative Example C
Comparative Example A was repeated except that fabric 2 was replaced with fabric 1. The arc rating of this laminate was measured and shown in the table.

Example 2
Example 1 was repeated except that fabric 2 was replaced with fabric 1. The arc rating of this laminate was measured and shown in the table.

Example 3
Three layers of 1.5 osyNomex (registered trademark) / Kevlar (registered trademark) spunlace fabric, known as E-89, are overlaid on fabric 2 and covered with fabric 4 to form a multilayer fabric laminate with high arc performance. Form. As a result, a multilayer fabric laminate having the fabric 4 as the outer layer and the fabric 2 as the inner layer is formed. When the layer of fabric 4 is positioned near the arcing point and the fabric 1 is positioned near the virtual wearer of the garment and used for garments, this multilayer fabric laminate provides excellent arc performance will do.

Example 4
The multilayer fabric laminate is cut into a fabric shape for each pattern, and the shapes are stitched together to form a three-quarter-length coat, whereby the multilayer fabric laminate of Example 1 is applied to protective clothing in the form of a coat. Produced. The multilayer fabric laminate of Example 1 was sewn to the coat so that fabric 3 formed the outer layer of the coat and fabric 1 formed a layer closer to the wearer.

Example 5
Example 4 is repeated, but using the multilayer fabric laminate of Example 3, with the layer positioned on the coat so that fabric 4 forms the outer layer of the coat and fabric 1 forms a layer closer to the wearer. Attached. In addition, a lightweight cotton lining is used to line the inside of the coat and position it between the wearer and the fabric 1.

Example 6
The multi-layer fabric laminate of Examples 1, 2, and 3 is used to make a variety of protective garments including coveralls, jumpsuits, and hoods. In each garment, the outer layers of the multi-layer fabric laminate described above (fabrics 3, 3, and 4 respectively) form the outer surface layer of the garment.

Claims (12)

A protective garment having use in an environment where electric arc is possible, the garment comprising an arc-resistant multi-layer fabric laminate,
i) a first layer of a flame resistant woven fabric comprising a first flame retardant fiber that forms the outer surface of the garment and is made from a synthetic polymer comprising a halogen;
ii) a second layer of flame resistant woven fabric comprising a second flame retardant fiber made from a synthetic polymer;
The first flame retardant fiber has a pyrolysis temperature that is at least 70 ° C. lower than the second flame retardant fiber, and the first layer fabric and the second layer fabric are different from each other; A protective garment in which a layer is positioned on the garment closer to the potential environment of the electric arc than the second layer.   The protective garment according to claim 1, wherein the first flame retardant fiber is present in the woven fabric of the first layer in an amount of at least 20% by weight.   The protective garment according to claim 2, wherein the halogen is chlorine.   The protective garment according to claim 3, wherein the first flame-retardant fiber is modacrylic.   The protective garment according to claim 1, wherein the flame resistant woven fabric of the second layer comprises an aramid fiber, a polybibenzimidazole fiber, or a polybenzoazole fiber, or a blend of any of the fibers.   The protective garment of claim 1, wherein the first layer is in direct contact with the second layer.   The protective garment according to claim 1, wherein the flame-resistant woven fabric of the first layer and the flame-resistant woven fabric of the second layer are separate fabric layers having no shared vertical or horizontal fabric yarn. The protective garment according to claim 1, further comprising 1 to 4 layers of a heat insulating fabric of 0.5 to 3.0 oz / yd ² located between the first flame resistant fabric and the second flame resistant fabric. . A method of making a protective garment having use in an environment where electric arc is possible,
i) providing a first flame resistant woven fabric comprising a first flame retardant fiber made from a synthetic polymer comprising a halogen;
ii) providing a second flame resistant woven fabric comprising a second flame retardant fiber made from a synthetic polymer,
The first flame retardant fiber has a pyrolysis temperature that is at least 70 ° C. lower than the second flame retardant fiber, and the first flame resistant woven fabric and the second flame resistant woven fabric are different from each other;
iii) combining the first flame resistant woven fabric and the second flame resistant woven fabric to form an arc resistant multilayer fabric laminate,
The first flame resistant woven fabric and the second flame resistant woven fabric are separate fabric layers having no shared vertical or horizontal fabric yarn;
iv) Arc resistance from the arc-resistant multi-layer fabric laminate, wherein the first flame-resistant woven fabric is positioned in the garment closer to a more likely electric arc environment than the second layer. Forming a garment.   The method for producing an arc-resistant garment according to claim 9, wherein the first flame-retardant fiber is modacrylic.   10. The arc resistant garment according to claim 9, wherein the second flame resistant woven fabric comprises aramid fibers, polybibenzimidazole fibers, or polybenzoazole fibers, or any blend of these fibers. How to make. In step iii), further comprising the step of positioning 1-4 layers of 0.5-3.0 oz / yd ² heat insulating fabric between the first flame resistant woven fabric layer and the second flame resistant woven fabric layer. A method of making an arc-resistant garment according to claim 9 comprising.

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