Fire-resistant shield for a protective film roof

Abstract

An inverted roof membrane assembly comprising: a) a waterproof membrane suitable for direct or indirect attachment onto a roof deck; b) at least one layer of a polymeric foam insulation board disposed directly or indirectly on a); c) a fire-resistant fabric shield having a water vapor transmission rate of 1.0 perm or more disposed directly or indirectly on b); and d) a ballast layer disposed directly or indirectly on c).

Description

Technical Field

[0001] The present invention relates to a roof structure including a foamed polystyrene sheet material, particularly an inverted roof membrane assembly (IRMA), also known as a "protected membrane roof" (PMR), which includes a layer of foamed polystyrene sheet material as a heat insulation layer.

Background Art

[0002] ASTM E108 is a fire test standard used to evaluate roof coverings for materials used on combustible or non-combustible decks for both residential and commercial roofing applications. The evaluation simulates a fire occurring outside a building with wind conditions.

[0003] In many applications, extruded polystyrene (XPS) foam is an excellent candidate for the insulation layer of IRMA due to a combination of excellent mechanical properties, excellent insulation value, resistance to water intrusion, and low cost. XPS foam is manufactured as a sheet material that is easy to install and can be easily adapted to specific roof shapes. IRMA typically also includes a concrete screed as the outer surface of the roof. These concrete screeds successfully protect the XPS foam in the ASTM E108 test, regardless of the size of the gap between the XPS and the screed, enabling the entire roof system to pass the test.

[0004] However, in the configuration of a PMR where a concrete screed is installed on a pedestal, if a fire enters the cavity and persists there, there is a concern that the flame will spread in the cavity formed between the foam and the bottom of the screed. Therefore, a flame shield that can be incorporated into IRMA or PMR (used interchangeably herein) is desired to further reduce the risk of continuous flame spread in the cavity between the foamed polystyrene insulation and the screed.

Summary of the Invention

Means for Solving the Problems

[0005] The present invention relates to a) a waterproof membrane suitable for being directly or indirectly attached onto a roof deck; b) at least one layer of a polymeric foam insulation board disposed directly or indirectly on a); c) a fire-resistant fabric shield having a moisture permeability of 1.0 perm or more disposed directly or indirectly on b); d) a ballast layer disposed directly or indirectly on c); and relates to an inverted roof membrane assembly comprising the same.

[0006] The present invention relates to a fire-resistant fabric shield comprising staple fiber nonwoven felt, wherein the nonwoven felt has a moisture permeability of 1.0 perm or more, a basis weight of about 150 to 800 grams per square meter, and a thickness of about 1.5 to 6.0 mm; wherein: i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; ii) 0 to 80 weight percent of the total amount of staple fibers is crimped virgin meta-aramid staple fibers having a uniform cut length; and also relates to the fire-resistant fabric shield.

Brief Description of the Drawings

[0007]

Figure 1

Embodiments for Carrying Out the Invention

[0008] The present invention relates to an inverted roof membrane assembly (IRMA) on a roof deck that sequentially includes a waterproof membrane, at least one layer of a polymer foam insulation board, a fire-resistant fabric shield, and a ballast layer. A perspective view of the IRMA on a roof is shown in FIG. 1. The IRMA includes a waterproof membrane 11 directly attached onto a roof deck 10. At least one layer of a polymer foam insulation board 12 is disposed directly on top of the waterproof membrane 11. In FIG. 1, two layers of the polymer foam insulation board 12 are shown. A fire-resistant fabric shield 14 is disposed directly on top of the layer of the polymer foam insulation board 12. Next, a ballast layer, such as a linear arrangement of concrete paving 16, is disposed on top of the fire-resistant fabric shield 14. In the embodiment shown in FIG. 1, the concrete paving 16 is indirectly disposed on top of the fire-resistant fabric shield 14 by using a series of pedestals 15.

[0009] As used herein, the use of the words "direct" or "directly" with respect to a layer or article means that a first layer or article is in contact with a second layer or article. "Directly attached" means that a first layer or article is in adjacent contact with a second layer or article, and the layers or articles are preferably vertically adjacent, for example, one layer or article is disposed on top of the other layer or article. Further, the use of the words "indirect" or "indirectly" with respect to a layer or article means that a first layer or article is not in contact with a second layer or article. "Indirectly attached" means that a first layer or article is adjacent to but not in contact with a second layer or article, which means that some additional intermediate layer or article is preventing contact between the first and second layers or articles. However, even so, the first and second layers or articles are preferably vertically adjacent, for example, the first layer or article is disposed on top of one or more intermediate layers or articles and as a result is disposed on top of the second layer or article.

[0010] Waterproof membrane The waterproof membrane is typically installed on the roof deck of a flat or low-slope roof. The roof deck can support the overlying layers and articles and can be concrete, reinforced concrete, metal, wood, composite materials, organic polymers, or other building materials capable of withstanding the imposed loads.

[0011] A waterproof membrane suitable for such direct or indirect attachment onto the roof deck can be an elastomeric or rubberized material having durability, flexibility, and suitable for preventing water intrusion from the environment onto the surface of the roof deck. In some embodiments, the waterproof membrane is a rubberized asphalt membrane, an example of which is the liquid-applied Monolithic Membrane 6125® available from American Hydrotech, Inc., Chicago, IL. Preferably, the waterproof membrane is a seamless membrane. This means that there are no seams in the final waterproof membrane that could potentially leak over time. Multiple layers of a liquid coating may be applied to the roof and a fiber-reinforcing membrane may be added between the coatings that become part of the waterproof membrane. In some embodiments, the thickness of the waterproof membrane (including fiber reinforcement) preferably has a final thickness of 2 - 10 mm.

[0012] In some embodiments, the waterproof membrane is a thermoplastic or thermosetting rubber such as thermoplastic olefin, ethylene-propylene-diene terpolymer, or polyvinyl chloride. Bitumen rubber membranes such as modified bitumen styrene-butadiene-styrene rubber membranes are also useful. The bitumen rubber membrane may be reinforced with glass fibers and / or polymer fibers.

[0013] Specifically, during the construction of the roof, in order to protect the waterproof membrane from damage, especially from damage caused by walking, an optional additional protective layer, which is a fiber-reinforced elastomer sheet, can be installed on top of the waterproof membrane between at least one layer of the waterproof membrane and the polymer foam insulation board. Typically, during the installation of the waterproof membrane, the protective layer is embedded in the waterproof membrane, thereby obtaining excellent adhesion of the protective layer to the waterproof membrane. One example of the protective layer is Hydroflex30® available from American Hydrotech, Inc., Chicago, IL. For the purposes of this specification, if a protective layer is used, it is considered part of the waterproof membrane. In some embodiments, the nominal thickness of the protective layer is 1 to 3 mm, and the thickness of the entire waterproof membrane can be increased to 3 to 13 mm.

[0014] The insulation material can be installed directly on top of the waterproof membrane. Alternatively, one or more optional layers may be installed between the waterproof membrane and the insulation material. Examples of such optional layers can include, for example, a drainage layer or another sheet-like layer. Similarly, if necessary, one or more of the aforementioned optional layers may be installed between the waterproof membrane and the layer of polymer foam insulation board.

[0015] Polymer foam insulation board At least one layer of the polymeric foam insulation board is installed directly or indirectly on the waterproof membrane layer. The polymeric foam insulation board is typically in the form of a rectangular or square sheet material having a length (longest dimension) of 0.61 meters (24 inches) to 3.66 meters (12 feet), particularly 1.83 to 3.66 meters (6 to 12 feet), and a width (perpendicular to the length along the major surface) of 0.305 meters (12 inches) to 3.66 meters (12 feet), particularly 0.46 meters (18 inches) to 2.44 meters (8 feet) or 0.61 meters (2 feet) to 1.83 meters (6 feet). The polymeric foam insulation board may be rabbeted along one or more edges (preferably all four edges) to facilitate fitting with adjacent portions of the polymeric foam insulation board during installation. In some embodiments, at least one layer of the polymeric foam insulation board includes at least two polymeric foam insulation board layers located directly or indirectly on the waterproof membrane layer.

[0016] The polymeric foam insulation board may additionally include an upper facing material and a lower facing material. "Upper" and "lower", when used with respect to the facing materials, refer to the orientation of the polymeric foam insulation board during installation, such as the installation of an inverted roof membrane assembly. The "upper" facing material faces outward, i.e., towards the outside of the structure, during installation and forms the upper surface of the polymeric foam insulation board. When installed in a roof structure, the lower facing material is on the side of the polymeric foam insulation board facing the waterproof membrane and the roof deck, while the upper facing material is on the opposite side of the polymeric foam insulation board, faces the ballast and the exposed roof surface, and forms the upper surface of the polymeric foam insulation board. In one embodiment, the upper and lower facing materials form a substantial barrier to water vapor diffusion (less than 1 perm, further less than 0.5 perm, further less than 0.1 perm).

[0017] The polymer foam insulation board contains one or more organic polymers such as one or more alkenyl aromatic polymers. The term "alkenyl aromatic polymer" means a homopolymer of an alkenyl aromatic monomer, a copolymer of two or more alkenyl aromatic monomers, or a polymer (such as a random, block, and / or graft copolymer) of at least 50 wt%, preferably at least 70 wt% or at least 75 wt% of one or more alkenyl aromatic monomers and up to 50 wt%, preferably up to 30 wt%, or up to 25 wt% of one or more other monomers that are not alkenyl aromatic monomers. Examples of alkenyl aromatic monomers include styrene, alpha-methylstyrene, ethylstyrene, vinyltoluene, chlorostyrene, and bromostyrene. Examples of other monomers include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, itaconic acid, acrylonitrile, maleic anhydride, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, vinyl acetate, and butadiene.

[0018] Alkenyl aromatic polymers are thermoplastic and can be linear or branched. Alkenyl aromatic polymers can have a weight average molecular weight measured by gel permeation chromatography relative to linear polystyrene standards of at least 40,000 g / mol, at least 60,000 g / mol, or at least 75,000 g / mol. This can also have a weight average molecular weight of, for example, up to 500,000 g / mol, up to 300,000 g / mol, up to 250,000 g / mol, or up to 150,000 g / mol. Alkenyl aromatic polymers can have a polydispersity (weight average molecular weight ÷ number average molecular weight) of 1 to 3 or more, preferably 1 to 2.5. In some embodiments, water is soluble in the alkenyl aromatic polymer up to a range of 0.09 to 2.2 moles (mol / kg), preferably 0.15 to 2.2 mol / kg, per kg of alkenyl aromatic polymer at a pressure of 130 °C and 101 kPa.

[0019] Particularly interesting alkenyl aromatic polymers are styrene homopolymers, as well as random and / or block copolymers of styrene and acrylonitrile. Particularly preferred alkenyl aromatic polymers are random and / or block copolymers comprising 0.1 to 30% by weight of polymerized acrylonitrile, 70 to 99.9% by weight of polymerized styrene, and 0 to 2% by weight of one or more other monomers (such as other alkenyl aromatic monomers). Such styrene-acrylonitrile copolymers may, for example, contain at least 5% by weight or at least 10% by weight of polymerized acrylonitrile, and may contain up to 25% by weight, up to 22.5% by weight or up to 20% by weight of polymerized acrylonitrile. Such styrene-acrylonitrile copolymers can exhibit a positive "skew" between the average and median copolymerized acrylonitrile distributions, and / or a positive percent difference, as defined respectively in U.S. Patent No. 8,324,287, and may alternatively or additionally have an average copolymerized acrylonitrile content of 20% by weight or less.

[0020] The alkenyl aromatic polymer preferably contains 20% by weight or less of halogen, more preferably 10% by weight or less of halogen or 5% by weight or less of halogen. Even less halogen may be included, or no halogen may be included.

[0021] Two or more alkenyl aromatic polymers may be present. Further, the organic polymer may contain one or more other organic polymers that are not alkenyl aromatic polymers. Such other organic polymers, if present, preferably constitute 15% by weight or less, more preferably 5% by weight or less of the total weight of all organic polymers. The other organic polymer may be more hydrophilic than the alkenyl aromatic polymer. For example, water can dissolve in the other organic polymer in an amount exceeding 2.2 mol / kg at a pressure of 130 °C and 101 kPa. Examples of such other organic polymers include copolymers of ethylene and one or more of acrylic acid, methacrylic acid, C1-4 polycarboxylic acids, and / or acrylate monomers; polyvinyl acetate; and polyacrylonitrile.

[0022] The foam of the polymer foam insulation board contains at least 0.25 weight percent, at least 0.5 weight percent, or at least 1.0 weight percent of one or more infrared attenuation additives, i.e., additives that suppress the transmission of infrared rays through the polymer foam, based on the weight of the foam. The foam of the polymer foam insulation board may contain, for example, up to 5 weight percent, up to 3 weight percent, or up to 2 weight percent of infrared attenuation additives. Among useful infrared absorption additives, various forms of carbon (e.g., including one or more of graphite; carbon black; soot; carbon fibers, flakes or powders; carbon nanotubes and fullerenes, powdered amorphous carbon, etc.), metal flakes, metal and semimetal oxides, such as titanium dioxide, silicon dioxide, manganese(IV) oxide, magnesium oxide, bismuth(III) oxide, cobalt oxide, zirconium(IV) oxide, molybdenum(II) oxide, calcium oxide, and alumina boehmite can be mentioned. Preferred polymer layers contain 0.25 to 5 weight percent, preferably 0.25 to 3 weight percent of one or more forms of carbon, especially graphite, carbon black, or mixtures thereof.

[0023] The foam of the polymeric foam insulation board comprises gas-containing cells. In some embodiments, the gas in the cells comprises at least one fluorocarbon having from 1 to 4 carbon atoms. In some embodiments, the fluorocarbon is chlorine-free. Examples of such fluorocarbons include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane, difluoromethane, perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, perfluorobutane, perfluorocyclobutane, trifluoropropene, 1,3,3,3-tetrafluoropropene (1234ze), 1,1,3,3-tetrafluoropropene, 2,2,3,3-tetrafluoropropene (1234yf), 1,2,3,3,3-pentafluoropropene (1225ye), 1,1,1-trifluoropropene, 1,1,1,3,3-pentafluoropropene (1225zc), 1,1,2,3,3-pentafluoropropene (1225yc), (Z)-1,1,1,2,3-pentafluoropropene (1225yez), 1-chloro-3,3,3-trifluoropropene (1233zd) and 1,1,1,4,4,4-hexafluorobut-2-ene (1336mzzm), and other hydrofluoroolefins (HFO) and / or hydrofluorochloroolefins (HFCO) blowing agents (component d), such as those described in US Patent Application Publication No. 2007 / 0100010. The gas in the cells in some embodiments comprises carbon dioxide; water; and / or one or more C1-9 hydrocarbons. In a preferred embodiment, the gas in the cells comprises at least one fluorocarbon, carbon dioxide, water, and optionally at least one hydrocarbon.

[0024] The foam in the polymeric foam insulation board has a density of up to 56 kg / m 3 (3.5 pounds per cubic foot (pcf)). The density of the foam is at least 21 kg / m 3(1.3 pcf), at least 28 kg / m 3 (1.75 pcf) or at least 32 kg / m 3 (2 pcf), and in some embodiments, up to (56 kg / m 3 )(3.5 pcf) or up to 40 kg / m 3 (2.5 pcf). The foam of the polymeric foam insulation board may contain other materials that perform useful functions. Examples of such other materials include, for example, pigments (other than infrared attenuation additives), fillers, antioxidants, extrusion aids, cell nucleating agents (other than infrared attenuation additives), antistatic agents, flame retardants and / or smoke suppressants, acid scavengers, and the like.

[0025] The polymeric foam insulation board preferably has a thickness of at least 0.6 cm (0.25 inches). The thickness may be any large value such as up to 45.7 cm (18 inches), up to 30.5 cm (12 inches), up to 20.3 cm (8 inches), or up to 15.24 cm (6 inches). Particularly preferred thicknesses are at least 7.62 cm (3 inches) or at least 10.16 cm (4 inches), and up to 20.3 cm (8 inches) or up to 15.24 cm (6 inches).

[0026] When measured according to ASTM C518 - 17 at an average temperature of 24°C, the polymeric foam insulation board preferably has an RSI value of at least 0.53 K·m 2 / W per 25.4 mm of thickness. The RSI value may be at least 1.0, at least 1.05, at least 1.1, at least 1.25, or at least 1.4 K·m 2 / W per 25.4 mm of thickness. The RSI value in some embodiments is up to 2, up to 1.75, up to 1.6, or up to 1.5 K·m 2 / W per 25.4 mm of thickness.

[0027] In some embodiments, the polymeric foam insulation board used in the inverted roof membrane assembly is up to 56 kg / m 3A foam density of (3.5 pounds per cubic foot), a thickness of at least 0.6 cm (0.25 inches), and at least 0.53 K·m per 25.4 mm of thickness 2 / W RSI value (13.01 F°·ft 2 ·h / BTU / R value per inch of thickness). In some embodiments, the polymeric foam insulation board has a foam density of 21 - 56 kg / m 3 and a thickness of 7.62 - 15.24 cm.

[0028] The polymeric foam insulation board is preferably an extruded foam produced by forming a pressurized mixture of a heat-softened alkenyl aromatic polymer, one or more blowing agents, an infrared absorbing additive, and any other optional components (if present), and then exposing the pressurized mixture to a lower pressure and temperature, whereby the mixture expands and cools to form a cellular foam. Such extrusion processes are well known and are described, among others, in U.S. Patent Nos. 5,380,767, 8,324,287, and 9,051,438. The extrusion process is conveniently carried out using a single-screw or twin-screw extruder to form the pressurized mixture, which exits the extruder through a die, typically a dog-bone shaped die, after which the mixture expands and cools. An accumulating extrusion process as described in U.S. Patent Application Publication No. 2008-0139682A is also useful.

[0029] The gas within the cells of the polymer foam obtained in the polymer foam insulation board corresponds, at least initially, to the blowing agent used in the production of the foam. Thus, the blowing agent can include, for example, a fluorocarbon having 1 to 4 carbon atoms such as those described above; carbon dioxide; water; and one or more of C1 - 9 hydrocarbons. In some embodiments, the blowing agent is a mixture comprising a fluorocarbon having 1 to 4 carbon atoms; carbon dioxide and water; in such a mixture, the fluorocarbon can be provided, for example, in an amount of 0.4 to 2, particularly 0.5 to 1.2 mol (mol / kg) per kg of the alkenyl aromatic polymer; carbon dioxide can be provided, for example, in an amount of 0.1 to 0.5, particularly 0.2 to 0.4 mol / kg; and water can be provided, for example, in an amount of 0.15 to 2, particularly 0.25 to 1.5 mol / kg, and the total amount of the blowing agent is 0.65 to 2.5 mol / kg. Such a blowing agent mixture is described, for example, in U.S. Patent Application Publication No. 2008 / 140892.

[0030] At least one layer of the polymer foam insulation board can be installed in the same way as a conventional foam insulation board by covering it with a waterproof membrane and overlapping the individual parts of the board adjacent to each other to form a heat insulation and protection structure on the waterproof membrane. When rabbeting is performed, the individual parts of the board can be fitted together to form a rabbet joint between adjacent parts of the board. It is possible to perform shiplap processing on adjacent parts of the board, or further perform interlock processing via corresponding fitting rabbets in each of the adjacent board parts. When shiplap processing is performed, grooves are formed between the outer surfaces of adjacent parts of the board, and these can function to drain water or direct water towards the edge of the roof.

[0031] At least one polymer foam insulation board layer may or may not be fixed to the underlying structure. Optionally, it may be fixed by using an adhesive or by any suitable mechanical fixing method. Alternatively, or in addition thereto, at least one polymer foam insulation board layer is at least partially loosely arranged and at least partially held in place by an article placed on the layer or layers.

[0032] Fire-resistant fabric shield In some embodiments, the present invention relates to an inverted roof member assembly including a fire-resistant fabric shield installed directly or indirectly on at least one polymer foam insulation board layer, the fire-resistant fabric shield having a moisture vapor transmission rate of 1.0 perm or more.

[0033] In some other embodiments, the present invention also relates to a fire-resistant fabric shield including a non-woven felt of staple fibers. The non-woven felt has a moisture vapor transmission rate of 1.0 perm or more and, in some embodiments, has a basis weight of about 150 to 800 grams per square meter and a thickness of about 1.5 to 6.0 mm. In some embodiments, the non-woven felt i) 20 to 100 weight percent of the total amount of staple fibers, recycled meta-aramid staple fibers, and ii) 0 to 80 weight percent of the total amount of staple fibers, crimped virgin meta-aramid staple fibers having a uniform cut length, and including. In some embodiments, the non-woven felt has a basis weight of about 150 to 400 grams per square meter and a thickness of about 1.5 to 4.0 mm.

[0034] It should be understood that all features, options, and elements described herein for the fire-resistant fabric shield are equally applicable to the fire-resistant fabric shield used in the inverted roof member assembly and to the fire-resistant fabric shield article itself.

[0035] In some specific embodiments, the present invention relates to an inverted roof member assembly including a fire-resistant fabric shield comprising a felt of staple fibers, the felt having a moisture permeability of 1.0 perm or more, a basis weight of about 150 to 800 grams per square meter, and a thickness of about 1.5 to 6.0 mm, i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; ii) 0 to 80 weight percent of the total amount of staple fibers is crimped virgin meta-aramid staple fibers having a uniform cut length.

[0036] In some embodiments, the felt of the fire-resistant fabric shield has a basis weight of about 150 grams to about 400 grams per square meter and a thickness of about 1.5 to 4.0 mm.

[0037] In some further embodiments, the fire-resistant fabric shield i) 40 to 80 weight percent of the total amount of staple fibers, recycled meta-aramid staple fibers, and ii) 20 to 60 weight percent of the total amount of staple fibers, crimped virgin meta-aramid staple fibers having a uniform cut length, are included.

[0038] In some embodiments, at least 40 weight percent of the total amount of staple fibers of the fire-resistant fabric shield is long staple crimped staple fibers.

[0039] The fire-resistant fabric shield is considered to need to have a moisture permeability of 1 perm or more so that the structure can dry out reliably without the structure capturing water after being exposed to rain. In some embodiments, the fire-resistant fabric shield has a moisture permeability of 10 perm or less, and higher values are considered to impart excessive fabric openness that cannot function as a fire-resistant fabric shield.

[0040] In some embodiments, the fire-resistant fabric shield is a non-woven felt. A non-woven felt refers to a conventional felt structure typically achieved by bonding a bat of staple fibers by needle punching or hydroentanglement. Needle punching processes such as those disclosed in U.S. Patent Nos. 2,910,763 and 3,684,284, and hydroentanglement or spunlace processes such as those disclosed in Kirayoglu's U.S. Patent No. 4,556,601 describe processes known in the art for the manufacture of non-woven felts. Preferably, the non-woven felt is a needle-punched felt.

[0041] As used herein, the term "staple fiber" refers to fibers produced by cutting filaments to a length of about 15 cm (5.9 inches) or less, preferably 3 - 15 cm (1.2 - 5.9 inches), and most preferably 3 - 8 cm (1.2 - 3.1 inches). The staple fibers may be straight (i.e., non-crimped), or may be crimped to have a serrated crimp along their length at any crimp (or repeated bend) frequency.

[0042] As used herein, the term "reclaimed" meta-aramid staple fiber means meta-aramid staple fiber derived from filament raw materials or other fiber sources that are normally considered waste and processed. These "reclaimed" meta-aramid staple fibers can have as their source at least one of the following categories that generate meta-aramid filaments and meta-aramid fiber waste: i) Spinning machine filament waste, which are filaments that have been spun but are considered waste and processed without being packaged for sale as first-grade products. These filaments include filament waste generated at the start and stop of the spinning machine, as well as general spinning machine waste generated during malfunctions of the spinning machine; ii) Filaments that have been spun, wound onto packages, but are defective and considered waste and processed as such. These filaments include those with unacceptable uniformity, such as denier or color variations, filaments with mechanical or structural defects, and filaments with an unacceptable amount of spin finish or no spin finish and are generally not suitable for subsequent normal processing; iii) Bobbin tails, which are the filaments remaining on the bobbin after a specific length of yarn has been used from the bobbin and are not of a length that must be disposed of as waste; iv) Fibrous materials generated from the disassembly of woven or knitted fabrics in a fabric recycling process; v) Fibrous materials recovered from recycled items and other recycled materials.

[0043] Depending on the source, the "reused" meta-aramid staple fibers may or may not have crimps and may or may not be precisely cut. For example, filaments that have been spun, wound onto packages, but are defective and considered waste and processed as such, and bobbin tails may have sufficient quality to be crimped and precisely cut.

[0044] In some embodiments, the nonwoven felt, which is a fire-resistant fabric shield, consists essentially of the meta-aramid staple fibers described herein. As used herein, the term "consisting essentially of" with respect to a blend of fibers is intended to mean that the blend of fibers can additionally incorporate up to approximately 5 percent of additional materials or fibers that do not significantly affect the performance of the nonwoven felt.

[0045] Useful meta-aramid-containing fibers containing poly(metaphenylene isophthalamide) (MPD-I) fibers have a limiting oxygen index (LOI) of about 26 or more. This means that meta-aramid staple fibers preferably supply fibers that do not burn in air to the nonwoven felt. The limiting oxygen index (LOI) represents the minimum concentration of oxygen that aids the combustion of the polymer as a percentage. This is measured by passing a mixture of oxygen and nitrogen through a burning test piece and lowering the oxygen level until the critical level is reached. The LOI values for various plastics are determined by standard tests such as ISO 4589 and ASTM D2863. Since air nominally contains about 21 percent oxygen, materials with an LOI value less than 21 are classified as flammable, while materials with an LOI value greater than 21 are classified as self-extinguishing because they cannot sustain combustion at ambient temperature without an external energy contribution. When a blend of meta-aramid staple fibers and other fibers is present in the felt, it is considered that the other fibers preferably also need to have an LOI of at least 24. In some embodiments, the felt further comprises staple fibers having a limiting oxygen index (LOI) of 24 or more up to 80 weight percent, based on the total amount of staple fibers present in the felt. Specifically, the other staple fibers can be crimped staple fibers, particularly crimped virgin staple fibers made from a material having an LOI of 24 or more. Preferably, all of the fibers or fibrous materials of the nonwoven felt or the refractory fabric shield have an LOI of 24 or more.

[0046] The use of recycled meta-aramid staple fibers in the nonwoven felt of a fire-resistant fabric shield provides several advantages. For example, using these fibers avoids disposing of them as waste, thereby reducing the number of fibers sent to landfills, which is beneficial to the environment. An additional advantage is that using these fibers is useful for reducing the total cost of the felt. Another advantage is that the requirements for fire-resistant fabric shield applications are suitable for the use of such recycled meta-aramid staple fibers. 20 to 100 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt is the recycled meta-aramid staple fibers as defined herein. In some embodiments, 25 to 100 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt is the recycled meta-aramid staple fibers. In some other embodiments, at least 30 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt is the recycled meta-aramid staple fibers. In some other embodiments, the total amount of meta-aramid staple fibers that are recycled meta-aramid staple fibers in the nonwoven felt is 70 weight percent or less.

[0047] In some embodiments, at least a certain percentage of the recycled meta-aramid staple fibers have a varying cut length. Since the sources of waste filaments are diverse, not all of the filament raw materials used for recycled meta-aramid staple fibers can usually be crimped and cut by a normal staple cutting process. For example, filaments that have been spun and wound for packaging but have defects or bobbin tails can usually be cut into staples using a conventional crimping / cutting process as long as they are crimped meta-aramid filaments with a uniform cut length. However, the fibers resulting from the filament waste of a spinning machine and the disintegration of a fabric are usually recovered as a mass of filaments and thus are not suitable for a conventional crimping / cutting process. These filaments can instead be cut into staples using a cutting machine or other type of shredding operation. However, since the staples are not crimped and the cut length is not precisely controlled, meta-aramid staples with a varying cut length are obtained. In some embodiments, at least 20 weight percent of the recycled meta-aramid staple fibers have a varying cut length, and in some embodiments, the amount of recycled meta-aramid staple fibers having a varying cut length is 60 weight percent or less.

[0048] Thus, the recycled meta-aramid staple fibers can include recycled meta-aramid staple fibers having a varying cut length and recycled meta-aramid staple fibers having an exact cut length. In some embodiments, the recycled meta-aramid staple fibers having a varying cut length do not have crimps, and the recycled meta-aramid staple fibers having an exact cut length have crimps.

[0049] It is advantageous to use recycled meta-aramid staple fibers in the nonwoven felt, but in order to improve uniformity, it may be desirable to additionally use meta-aramid staple fibers that are not recycled meta-aramid staple fibers in the nonwoven felt. That is, since recycled meta-aramid staple fibers are produced from filament raw materials that are usually regarded as waste and processed, the variation in recycled meta-aramid staple fibers is greater than that of meta-aramid staple fibers manufactured from commercially available meta-aramid filaments.

[0050] Accordingly, 0 to 80 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt is crimped virgin meta-aramid staple fibers having a uniform cut length. In some embodiments, 0 to 75 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt is crimped virgin meta-aramid staple fibers having a uniform cut length.

[0051] The use of the term "virgin" with respect to fibers containing staple fibers herein means that the fibers are unused. That is, they have not been used previously for any application or in fiber products or other articles, and further, such fibers are not considered recycled fibers as described herein. These virgin fibers generally have a somewhat predictable uniformity of structure and appropriate quality, and thus can be used or sold as fibers for applications that require or desire unused fibers, such applications being those that will provide the first use of these virgin fibers in yarns, fabrics, and other structures of fiber products.

[0052] In addition, the term "crimped virgin meta-aramid staple fiber having a uniform cut length" as used herein means a meta-aramid staple fiber that is specially manufactured, crimped, cut, and packaged for use as a meta-aramid staple fiber in conventional fiber product applications (such as yarns, fabrics, and non-woven fabrics), and is not recycled meta-aramid staple fiber. In some embodiments, the meta-aramid staple fibers in the felt consist of recycled meta-aramid staple fibers and crimped virgin meta-aramid staple fibers having a uniform cut length.

[0053] If it is desirable for both recycled meta-aramid staple fibers and crimped virgin meta-aramid staple fibers having a uniform cut length to be present in the non-woven felt, preferably, the non-woven felt is manufactured from a blend of staple fibers in which both types of fibers are well mixed, i.e., a raw material in which both types of fibers are uniformly mixed. Further, if both recycled meta-aramid staple fibers and crimped virgin meta-aramid staple fibers having a uniform cut length are present in the non-woven felt, preferably, they are also arranged in the non-woven felt as a well-mixed blend, i.e., a blend in which the two types of fibers are uniformly mixed and dispersed within the felt. By being uniformly mixed within the felt, the occurrence of local regions where any one type of fiber is present at a high concentration in any part of the felt is avoided.

[0054] In addition, in some embodiments, at least 40 weight percent of the total amount of staple fibers in the nonwoven felt is crimped staple fibers. A supply of staple fibers where the crimped staple fibers are less than 50 weight percent is thought to have more problems in carding and other processing issues and make it more difficult to produce the nonwoven felt. In some embodiments, at least 60 weight percent of the total amount of staple fibers in the nonwoven felt is crimped staple fibers. In some other embodiments, 75 weight percent or less of the total amount of staple fibers in the nonwoven felt is crimped staple fibers.

[0055] In some preferred embodiments, the staple fibers having crimp have a crimp frequency of 2.5 to 5.5 crimps per centimeter (7 to 14 crimps per inch), and in some embodiments, both staple fibers of uniform cut length and staple fibers of varying cut length have crimp. In some preferred embodiments in the nonwoven felt, the staple fibers including both uniform cut length and varying cut length have a cut length of at least 1.0 centimeter (0.4 inch). In some preferred embodiments in the nonwoven felt, the staple fibers including both uniform cut length and varying cut length have a cut length of at most 10.1 centimeters (4.0 inches). As used herein, "uniform cut length" and "accurate cut length" have the same meaning and are intended to be interchangeable. The staple fibers having a uniform cut length are preferably cut to a length of 3.8 to 10.1 centimeters (1.5 to 4.0 inches). In still some other embodiments, the nonwoven felt consists of 60 to 40 weight percent of meta-aramid staple fibers having a uniform or accurate cut length and 40 to 60 weight percent of meta-aramid staple fibers having a varying cut length, based on the total amount of meta-aramid staple fibers in the nonwoven felt.

[0056] In addition, in some embodiments, at least 20 weight percent of the crimped fibers are "long staple" fibers. As used herein, "long staple" means a crimped staple fiber having a cut length of 2.5 to 10.1 centimeters (1 to 4 inches). In some embodiments, at least 40 weight percent of the total amount of staple fibers in the refractory fabric shield are long staple crimped staple fibers. Optionally, other fibers such as glass, polyacrylonitrile, mineral wool, or mixtures thereof can be combined with the recycled meta-aramid staple fibers.

[0057] The nonwoven felt has a basis weight of 150 to 800 grams per square meter, and in some embodiments, the nonwoven felt has a basis weight of at least 200 grams per square meter. In some embodiments, the nonwoven felt has a basis weight of 150 to 400 grams per square meter, preferably 200 to 400 grams per square meter. The nonwoven felt further has a thickness of 1.5 to 6.0 mm, and in some embodiments, the nonwoven felt has a thickness of 1.5 to 4.0 mm. These basis weights and thicknesses of the nonwoven felt can provide a single-layer refractory fabric shield. That is, a single layer of nonwoven felt can function as desired by IRMA. However, optionally, the refractory fabric shield can include multiple layers of the nonwoven felt described herein. Alternatively, the refractory fabric shield can include a stack of one or more layers of the nonwoven felt described herein with one or more layers of one or more felts that do not contain recycled meta-aramid staple fibers, provided that the addition of other nonwoven felts does not reduce the fire resistance performance of IRMA.

[0058] In some embodiments, meta-aramid staple fibers refer to staple fibers manufactured from filaments of an aramid polymer in which two rings or radicals are meta-oriented with respect to each other along the molecular chain. Poly(m-phenylene isophthalamide) (MPD-I) is a preferred meta-aramid polymer and a preferred meta-aramid staple fiber. MPD-I means a homopolymer obtained from the polymerization of an equimolar ratio of m-phenylenediamine and isophthaloyl chloride, as well as copolymers obtained by incorporating small amounts of other diamines into m-phenylenediamine and small amounts of other diacid chlorides into isophthaloyl chloride. In principle, other diamines and other diacid chlorides can be used in amounts up to about 10 mole percent of m-phenylenediamine or isophthaloyl chloride, or perhaps in slightly greater amounts provided only that the other diamines and diacid chlorides do not have reactive groups that interfere with the polymerization reaction. Additives can be used in the manufacture of meta-aramid fibers as long as the nonwoven felt made from the meta-aramid fibers functions adequately as a refractory fabric shield.

[0059] Meta-aramid filaments are typically spun by extruding a solution of a meta-aramid polymer through a capillary and removing the solvent by a dry or wet spinning process known in the art. In the case of poly(m-phenylene isophthalamide), the solvent of the solution is usually dimethylacetamide. The dope filaments containing the solvent are spun, then the solvent is removed, and then they are subjected to other treatments such as washing, drying, and optional heat treatment known in the art. Some useful processes for manufacturing meta-aramid fibers are disclosed, for example, in U.S. Patent Nos. 3,063,966 and 5,667,743. Additional useful methods for manufacturing meta-aramid fibers such as MPD-I-containing fibers include U.S. Patent Nos. 7,771,636, 7,771,637, 7,771,638, 7,780,889, and 7,998,575. Some of these patents disclose dry spinning of meta-aramid filaments using a spinning cell having a heated gas atmosphere, in which a heated gas is supplied to the spinning cell to remove the solvent. Thereafter, the meta-aramid filaments can be cut and crimped using conventional techniques to produce meta-aramid staple fibers.

[0060] Ballast The ballast layer is installed directly or indirectly on top of the fire-resistant fabric shield. The ballast material is a high-density, heavy material that holds the articles within the roof assembly, particularly the layers of the fire-resistant fabric shield and the polymeric foam insulation board, in place by gravity. The ballast material can include coarse or fine particle materials such as gravel, stone, soil, or medium. The ballast can be or include a planting medium for a green roof or other green roof structure, or a component of a green roof structure. The ballast can be or include a blue roof structure or a component thereof. Other ballast materials include paving materials of various shapes and sizes that can form continuous or discontinuous layers. A variety of ballast materials can be used in any roof structure. In some embodiments, the ballast of the inverted roof membrane assembly includes gravel, stone, soil, concrete paving materials, a green roof structure or a component thereof, or a blue roof structure or a component thereof.

[0061] Optionally, the ballast layer can be indirectly attached to the fire-resistant fabric shield by using other articles or layers disposed between the fire-resistant fabric shield and the ballast layer. One particularly useful arrangement is to use a series of pedestals inserted and spaced between the fire-resistant fabric shield and the ballast layer to provide support columns for the ballast layer, as shown in FIG. 1. These pedestals improve air circulation in the roof and are useful for reducing heat conduction from the ballast to the roof deck. The pedestals can be manufactured from any material that can adequately support the ballast material of interest, which are typically made of plastic, or metal, or a combination thereof, although other constituent materials are possible as needed. Any suitable arrangement of the pedestals can be used as long as the roof functions as desired.

[0062] Test methods Fire resistance. The performance of the fire-resistant fabric shield for roofing applications was measured using ASTM E108. ASTM E108 is a fire test standard used to evaluate roof coverings for both residential and commercial roofing applications for materials used on combustible or non-combustible decks. This evaluation simulates a fire occurring outside a building with wind conditions.

[0063] Water vapor transmission rate / water vapor transmission coefficient. The water vapor transmission rate (in US perm-inch units) and water vapor transmission coefficient (in US perm units) of the fire-resistant fabric shield are measured using ASTM E96.

[0064] Trapezoid tear strength. The trapezoid tear strength (in pounds per square inch units) of the fire-resistant fabric shield is measured using ASTM D4533.

[0065] Tensile strength / strain. The tensile strength (in pounds per square inch units) and strain (in percent units) of the fire-resistant fabric shield are measured using ASTM D882.

Example

[0066] Example 1 Multiple nonwoven samples in the form of needle-punched felts were produced from recycled meta-aramid staple fibers having various cut lengths from 0.4 to 2.5 inches, specifically poly(meta-phenylene isophthalamide) staple fibers, and precisely cut crimped virgin meta-aramid staple fibers having a uniform cut length of 3 inches, specifically poly(meta-phenylene isophthalamide) staple fibers. All meta-aramid staple fibers had a linear density of approximately 2.2 denier. The composition of the fibers used to produce the fiber feed for each fabric sample is shown in Table 1.

[0067] Each fiber supply was carded to form a web, which was then crosslapped to form a batt, and then needle punched. The batt was first needle punched at a needle density of 75 penetrations per square centimeter, and then needle punched three more times, each at a needle density of 125 penetrations per square centimeter, to bond it. The final thickness and basis weight of the felt are shown in Table 1.

[0068]

Table 1

[0069] Example 2 Next, the nonwovens of Articles 3 and 5 in Table 1 were evaluated for their flame spread performance using ASTM E108-20a(r2020)“Standard Test Methods for Fire Tests of Roof Coverings”. The test plan conformed to Section 7.1 of ASTM E108 and was for roof coverings restricted for use on non-combustible decks (steel, concrete, or gypsum). The only test required was the flame spread test. The fabric articles of the present invention were compared with the performance of two Atlas® FR-10 samples (Articles A and B). This is a known barrier for conventional roofs specially designed to be installed over wooden decks or certain combustible insulation materials and is a glass fiber mat with its own fire-resistant coating (FR-10&FR-50 Fire Retardant Slipsheet datasheet, Atlas Roofing Corporation).

[0070] The test configuration and results are shown in Table 2. As shown, the nonwovens of the present invention did not exhibit surface ignition and provided a fire-resistant fabric shield superior to the comparative materials.

[0071]

Table 2

[0072] Example 3 The nonwoven fabric article 5 in Table 1 is a mixture of 60 weight percent of recycled MPD-I fibers of various cut lengths (0.4 - 2.5 inches) and 40 weight percent of precisely cut (3 inches) MPD-I crimp virgin fibers, and was further tested to determine additional fabric properties. This is summarized in Table 3.

[0073] [Table 3]

Claims

1. An inverted roof membrane assembly, a) A waterproof membrane suitable for direct or indirect installation on a roof deck, b) at least one layer of polymer foam insulation board placed directly or indirectly on a), c) A fire-resistant fabric shield having a moisture permeability of 1.0 perm or more, placed directly or indirectly on b), d) A ballast layer placed directly or indirectly on c), An inverted roof membrane assembly including a roof.

2. The fire-resistant fabric shield includes a staple fiber felt, and the felt is Moisture permeability of 1.0 perm or higher, Approximately 150 to 800 grams per square meter, Approximately 1.5 to 6.0 mm thick, Having; i) 20 to 100 percent by weight of the total amount of staple fibers are recycled meta-aramid staple fibers; ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having a uniform cutting length; The inverted roof membrane assembly according to claim 1.

3. The aforementioned felt has a basis weight of approximately 150 to 400 grams per square meter, The inverted roof membrane assembly according to claim 2, having a thickness of approximately 1.5 to 4.0 mm.

4. The inverted roof membrane assembly according to claim 2 or 3, wherein the felt further comprises up to 80 weight percent of staple fibers having a limiting oxygen index of 24 or higher, based on the total amount of staple fibers present in the felt.

5. The inverted roof membrane assembly according to claim 2 or 3, wherein at least 40 weight percent of the total amount of staple fibers in the fire-resistant fabric shield are crimped staple fibers.

6. The aforementioned fire-resistant fabric shield, i) Recycled meta-aramid staple fibers, amounting to 40-80% by weight of the total staple fiber weight, ii) A crimped virgin meta-aramid staple fiber having a uniform cutting length, comprising 20 to 60 weight percent of the total amount of staple fibers, An inverted roof membrane assembly according to claim 2 or 3, comprising:

7. A fire-resistant fabric shield containing a nonwoven felt made of staple fibers, wherein the nonwoven felt is Moisture permeability of 1.0 perm or higher, Approximately 150 to 800 grams per square meter, Approximately 1.5 to 6.0 mm thick, Having; i) 20 to 100 percent by weight of the total amount of staple fibers are recycled meta-aramid staple fibers; ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having a uniform cutting length; Fire-resistant fabric shield.

8. i) 40 to 80 percent by weight of the total amount of staple fibers are recycled meta-aramid staple fibers. ii) 20 to 60 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having a uniform cutting length. The fire-resistant fabric shield according to claim 7.

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