Flame-retardant shield for protected film roofs

Abstract

An inverted roof membrane assembly comprising: a) a waterproof membrane adapted to be mounted directly or indirectly on top of a roof deck, b) at least one polymeric foam insulation panel directly or indirectly on top of a), c) a flame retardant fabric shield directly or indirectly on top of b), the flame-retardant fabric protective cover has a water vapor transmission rate of 1.0 perm or more; and d) a ballast layer directly or indirectly on top of c).

Description

Background Art

[0001] FIELD OF THE INVENTION The present invention relates to a roof structure comprising expanded polystyrene sheets, in particular an Inverted Roof Membrane Assembly (IRMA), also known as a "Protected Membrane Roof" (PMR), which comprises an expanded polystyrene sheet layer as an insulating layer.

[0002] ASTM E108 is a fire test response standard used to evaluate roof coverings of materials used on combustible or non-combustible floor decks in both residential and commercial roofs. The evaluation simulates a fire originating from outside the building in windy conditions.

[0003] In many applications, extruded polystyrene (XPS) foam is a good candidate for the thermal insulation layer in an IRMA because of its combination of good mechanical properties, good thermal insulation value, resistance to water penetration, and low cost. XPS foam is manufactured as a sheet that is easy to install and fits into specific roof geometries. IRMAs often also include concrete pavers as the exterior roof surface. Regardless of the size of the gap between the XPS and the pavers, these concrete pavers successfully protected the XPS foam during the ASTM E108 test, allowing the roof system as a whole to pass the test.

[0004] However, in PMR constructions where concrete pavers are mounted on a base, there is concern about the spread of fire within the cavity so formed between the foam and the bottom of the pavers if a fire is introduced and sustained therein. Therefore, what is needed is a flame shield that can be incorporated into an IRMA or PMR (used interchangeably herein) to further reduce the risk of fire spread if sustained within the cavity between the expanded polystyrene insulation and the pavers. Summary of the invention

[0005] The present invention relates to an inverted roof membrane assembly, comprising:

[0006] a) Suitable for waterproof membranes installed directly or indirectly on top of roof decking,

[0007] b) at least one layer of polymer foam insulation board directly or indirectly on top of a),

[0008] c) a flame retardant fabric shield directly or indirectly on top of b), the flame retardant fabric shield having a water vapor transmission rate of 1.0 perm or greater; and

[0009] d) A ballast layer directly or indirectly on top of c).

[0010] The present invention also relates to a flame retardant fabric protective cover comprising a nonwoven felt of staple fibers, the nonwoven felt having a water vapor transmission rate of 1.0 perm or greater, a basis weight of about 150 to 800 grams per square meter, and a thickness of about 1.5 to 6.0 mm;

[0011] in:

[0012] i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and

[0013] ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a perspective view of an inverted roof membrane assembly on a roof. DETAILED DESCRIPTION

[0015] The present invention relates to an inverted roof membrane assembly (IRMA) on a roof deck, which in turn includes a waterproof membrane, at least one layer of polymer foam insulation, a fire retardant fabric shield, and a ballast layer. Figure 1 A perspective view of an IRMA on a roof is shown. The IRMA includes a waterproof membrane 11 mounted directly on top of a roof deck 10. At least one layer of polymer foam insulation 12 is directly on top of the waterproof membrane 11. Figure 1 In FIG. 1 , two layers of polymer foam insulation panels 12 are shown. A fire retardant fabric shield 14 is directly on top of one or more layers of polymer foam insulation panels 12. Then, a ballast layer (such as a linear array of concrete pavers 16) is on top of the fire retardant fabric shield 14. Figure 1 In the illustrated embodiment, concrete pavers 16 are indirectly attached to the flame retardant fabric shield 14 through the use of a series of pedestals 15 .

[0016] As used herein, with respect to layers or articles, the words "directly" or "directly" are used to mean that a first layer or article is in contact with a second layer or article. "Directly mounted" means that a first layer or article is adjacent to and in contact with a second layer or article, and these layers or articles are preferably vertically adjacent, for example, one layer or article is placed on another layer or article. In addition, with respect to layers or articles, the words "indirectly" or "indirectly" are used to mean that the first layer or article is not in contact with the second layer or article. "Indirectly mounted" 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 layers or articles prevent the first layer or article from contacting the second layer or article; however, the first layer or article and the second layer or article are still preferably vertically adjacent, for example, the first layer or article is placed on one or more intermediate layers or articles, which in turn are placed on the second layer or article.

[0017] Waterproof membrane

[0018] The waterproof membrane is installed on top of the roof deck, typically on flat or low-slope roofs. The roof deck supports the layers and items covered above and can be of concrete, reinforced concrete, metal, wood, composites, organic polymers, or other building materials capable of bearing the superimposed weight.

[0019] The waterproof membrane suitable for such direct or indirect installation on top of the roof deck can be a durable, flexible elastomeric material or a rubberized material suitable for preventing water from entering the surface of the roof deck from the environment. In some embodiments, the waterproof membrane is a rubberized asphalt membrane, an example of which is a liquid-applied Monolithic Membrane commercially available from American Hydrotech, Inc. of Chicago, Illinois. Preferably, the waterproof membrane is a seamless membrane, which means that there are no seams in the final waterproof membrane that could leak over time. Multiple layers of liquid coatings may be applied to the roof with a fiber reinforced membrane added between these coatings, which fiber reinforced membrane becomes part of the waterproof membrane. In some embodiments, the thickness of the waterproof membrane (with any fiber reinforcement) preferably has a final thickness of 2 to 10 mm.

[0020] In some embodiments, the waterproof membrane is a thermoplastic or thermosetting rubber, such as a thermoplastic olefin, an ethylene-propylene-diene terpolymer, or polyvinyl chloride. Asphalt rubber membranes, such as modified asphalt styrene-butadiene-styrene rubber membranes, are also useful. Asphalt rubber membranes can be reinforced with glass and / or polymer fibers.

[0021] Specifically, in order to protect the waterproof membrane from damage during roof installation, especially from foot traffic, an optional additional protective layer, which is a fiber-reinforced elastomeric sheet, can be installed on top of the waterproof membrane, between the waterproof membrane and at least one layer of polymer foam insulation board. Typically, the protective layer is embedded in the waterproof membrane while the waterproof membrane is installed to obtain good adhesion of the protective layer to the waterproof membrane. An example of a protective layer is Hydroflex available from American Hyde Tech Co., Ltd. of Chicago, Illinois. For the purposes of this document, if a protective layer is used, it is considered to be part of the waterproof membrane. In some embodiments, the protective layer has a nominal thickness of 1 to 3 mm and it can increase the thickness of the entire waterproof membrane to 3 to 13 mm.

[0022] Although the insulation material can be installed directly on the waterproof membrane, alternatively, one or more optional layers can 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 material layer. Similarly, if desired, one or more of the optional layers just described can be installed between the waterproof membrane and one or more layers of polymer foam insulation.

[0023] Polymer foam insulation board

[0024] At least one layer of polymer foam insulation board is directly or indirectly mounted on top of the waterproof membrane layer. The polymer foam insulation board is typically in the form of a rectangular or square board having a length (longest dimension) of 0.61 meters (24 inches) to 3.66 meters (12 feet), especially 1.83 to 3.66 meters (6 to 12 feet) and a width (orthogonal to the length along the major surface) of 0.305 meters (12 inches) to 3.66 meters (12 feet), especially 0.46 meters (18 inches) to 2.44 meters (8 feet) or 0.61 meters (2 feet) to 1.83 meters (6 feet). The polymer foam insulation board can be notched along one or more edges (preferably all four edges) to facilitate mating with adjacent portions of the polymer foam insulation board during installation. In some embodiments, the at least one layer of polymer foam insulation board includes at least two layers of polymer foam insulation boards, which are directly or indirectly on top of the waterproof membrane layer.

[0025] The polymer foam insulation board may additionally include a top facing layer and a bottom facing layer. "Top" and "bottom" in relation to the facing layers refer to the orientation of the polymer foam insulation board when installed (such as in an inverted roof membrane assembly installation). The "top" facing layer refers to the facing layer that faces outward when installed, i.e., toward the exterior of the building, and forms the top surface of the polymer foam insulation board. When installed in a roof structure, the bottom facing layer is on the side of the polymer foam insulation board that faces the waterproof membrane and roof decking, while the top facing layer is on the opposite side of the polymer foam insulation board, facing the ballast and exposed roof surface and forming the top surface of the polymer foam insulation board. In one embodiment, the top facing layer and the bottom facing layer form a substantial barrier to water vapor diffusion (less than 1 perm, or even less than 0.5 perm, or also less than 0.1 perm).

[0026] The polymer foam insulation board comprises one or more organic polymers, which include one or more alkenyl-aromatic polymers. By "alkenyl-aromatic polymer", it is meant 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. Alkenyl-aromatic monomers include, for example, styrene, α-methylstyrene, ethylstyrene, vinyltoluene, chlorostyrene, and bromostyrene. Examples of other monomers include, for example, 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.

[0027] Alkenyl aromatic polymers are thermoplastic and can be linear or branched.Alkenyl aromatic polymers can have a weight average molecular weight of at least 40,000 g / mol, at least 60,000 g / mol or at least 75,000 g / mol as measured by gel permeation chromatography of a reference linear polystyrene standard. It can have, for example, a weight average molecular weight of up to 500,000 g / mol, up to 300,00 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 certain embodiments, water is soluble in alkenyl aromatic polymers at 130 ° C and 101 kPa pressure to an extent of 0.09 to 2.2 moles of water / kg alkenyl aromatic polymer (mol / kg), preferably 0.15 to 2.2 moles / kg.

[0028] Particularly interesting alkenyl aromatic polymers are random and / or block copolymers of styrene homopolymers and styrene and acrylonitrile. Particularly preferred alkenyl aromatic polymers are random and / or block copolymers containing 0.1 to 30 wt % of polymerized acrylonitrile, 70 wt % to 99.9 wt % of polymerized styrene and 0 to 2 wt % of one or more other monomers (such as other alkenyl aromatic monomers). Such styrene-acrylonitrile copolymers can contain, for example, at least 5 wt % or at least 10 wt % of polymerized acrylonitrile, and can contain up to 25 wt %, up to 22.5 wt % or up to 20 wt % of polymerized acrylonitrile. Such styrene-acrylonitrile copolymers can show a positive "deviation" and / or positive percentage difference between the average and median copolymerized acrylonitrile distribution, each as defined in U.S. Patent No. 8,324,287, and can alternatively or in addition have an average copolymerized acrylonitrile content of 20 wt % or less.

[0029] The one or more alkenyl aromatic polymers preferably contain no more than 20 weight percent halogen, more preferably no more than 10 weight percent halogen or no more than 5 weight percent halogen. They may contain any lesser amount of halogen and may be halogen-free.

[0030] There may be more than one alkenyl aromatic polymer. In addition, the organic polymer may include one or more other organic polymers that are not alkenyl aromatic polymers. Such other organic polymers, if present, preferably account for no more than 15 percent of the total weight of all organic polymers, and more preferably no more than 5 weight percent thereof. The other organic polymers may be more hydrophilic than the one or more alkenyl aromatic polymers. For example, at 130° C. and 101 kPa pressure, water may be soluble in the other organic polymers in an amount greater than 2.2 mol / kg. Examples of such other organic polymers include copolymers of ethylene with one or more of acrylic acid, methacrylic acid, C1-4 polycarboxylic acid and / or acrylate monomers; polyvinyl acetate and polyacrylonitrile.

[0031] The foam in 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 attenuating additives, i.e., additives that inhibit infrared radiation from penetrating the polymer foam, based on the weight of the foam. The foam in 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 one or more infrared attenuating additives. Among useful infrared absorbing additives are various forms of carbon (including, for example, one or more of the following: graphite; carbon black; soot; carbonized fibers, flakes or powders; carbon nanotubes and fullerenes, powdered amorphous carbon, etc.), metal flakes, metal and semi-metal 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 aluminum oxide boehmite. Preferred polymer layers contain 0.25 to 5, preferably 0.25 to 3 weight percent of one or more forms of carbon, especially graphite, carbon black, or mixtures thereof.

[0032] The foam in the polymer foam insulation panel includes gas-containing cells. In some embodiments, the gas in the cells contains at least one fluorocarbon having 1 to 4 carbon atoms. In some embodiments, the fluorocarbon does not contain chlorine. 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, trifluoropropylene, 1,3,3,3-tetrafluoropropylene (1234ze), 1,1,3,3-tetrafluoropropylene, 2,2,3,3-tetrafluoropropylene (1234yf), 1,2,3,3,3-pentafluoro Propylene (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)), including those described in, for example, US2007 / 0100010. In some embodiments, the gas in the cells includes carbon dioxide; water; and / or one or more C1-9 hydrocarbons. In preferred embodiments, the gas in the cells includes at least one fluorocarbon, carbon dioxide, water, and optionally at least one hydrocarbon.

[0033] The foam in the polymer foam insulation board has a maximum of 56 kg / m 3 (3.5 pounds per cubic foot (pcf)) density. The foam density can be at least 21 kg / m 3 (1.3pcf), at least 28kg / m 3 (1.75pcf) or at least 32kg / m 3 (2pcf), and in some embodiments can be up to (56kg / m 3 )(3.5pcf) or up to 40kg / m 3 (2.5pcf).

[0034] The foam in the polymer foam insulation board may contain other materials that perform useful functions. Examples of such other materials include, for example, pigments (in addition to one or more infrared attenuating additives), fillers, antioxidants, extrusion aids, cell nucleating agents (in addition to one or more infrared attenuating additives), antistatic agents, flame retardants and / or smoke suppressants, acid scavengers, etc.

[0035] The polymer foam insulation board preferably has a thickness of at least 0.6 cm (0.25 in). The thickness may be any greater value, such as up to 45.7 cm (18 in), up to 30.5 cm (12 in), up to 20.3 cm (8 in), or up to 15.24 cm (6 in). Particularly preferred thicknesses are at least 7.62 cm (3 in) or at least 10.16 cm (4 in) and up to 20.3 cm (8 in) or up to 15.24 cm (6 in).

[0036] The polymer foam insulation board preferably has a thermal conductivity of at least 0.53 K·m as measured according to ASTM C518-17 at an average temperature of 24°C. 2 / W / 25.4mm 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 / 25.4mm thickness. In some embodiments, the RSI value is up to 2, up to 1.75, up to 1.6, or up to 1.5 K·m 2 / W / 25.4mm thickness.

[0037] In some embodiments, the polymer foam insulation board used in the inverted roof membrane assembly has a thermal conductivity of at most 56 kg / m 3 (3.5 lbs / cubic foot) foam density, at least 0.6 cm (0.25 in) thickness, at least 0.53 K·m 2 / W / RSI value of 25.4mm thickness (13.01F°·ft 2h / BTU / inch thickness). In some embodiments, the polymer foam insulation board has an R-value of 21 to 56 kg / m 3 Foam density and thickness from 3 to 5 inches.

[0038] The polymer foam insulation board is preferably an extruded foam made by forming a pressurized mixture of one or more heat-softened alkenyl aromatic polymers, one or more blowing agents, one or more infrared absorbing additives and other optional ingredients (if any), and then exposing the pressurized mixture to a relatively low pressure and temperature so that the mixture expands and cools to form a cellular foam. Such extrusion processes are well known and are described, for example, in U.S. Patent Nos. 5,380,767, 8,324,287 and 9,051,438 and many other references. The extrusion process is conveniently performed using a single screw or twin screw extruder to form a pressurized mixture, which leaves the extruder through a die (typically a dog-bone die), after which the mixture expands and cools. Cumulative extrusion processes as described in U.S. Published Patent Application No. 2008-0139682A are also useful.

[0039] The gas in the cells of the resulting polymer foam in the polymer foam insulation board corresponds at least initially to the blowing agent used to make the foam. Thus, the blowing agent may include, for example, one or more of the following: a fluorocarbon having 1 to 4 carbon atoms as described above; carbon dioxide; water; and a C1-9 hydrocarbon. 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 may be provided, for example, in an amount of 0.4-2, especially 0.5 to 1.2 mol / kg of one or more alkenyl aromatic polymers (mol / kg); carbon dioxide may be provided, for example, in an amount of 0.1 to 0.5, especially 0.2 to 0.4 mol / kg; and water may be provided, for example, in an amount of 0.15 to 2, especially 0.25 to 1.5 mol / kg, wherein 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 US2008 / 140892.

[0040] At least one layer of polymer foam insulation can be installed in the same manner as conventional foam insulation, by laying individual sections of the sheet adjacent to each other to cover the waterproof membrane and form an insulating and protective structure above the waterproof membrane. When the notches engage, the individual sections of the sheet can be mated to form a notch joint between adjacent sheet sections. Adjacent sheet sections can be boat-lapped or even interlocked by corresponding mating notches on each adjacent sheet section. When boat-lapped, channels are formed between the top surfaces of adjacent sheet sections; these channels can serve to direct water toward a drain or roof edge.

[0041] The at least one polymer foam insulation board layer may or may not be secured to the underlying structure. Alternatively, it may be secured by use of an adhesive or by any suitable mechanical fastening method. Alternatively or in addition, the at least one polymer foam insulation board layer is at least partially loosely laid and at least partially held in place by a layer or item mounted on top of the one or more layers.

[0042] Flame retardant fabric protective cover

[0043] In some embodiments, the present invention is directed to an inverted roof assembly comprising a flame retardant fabric shield mounted directly or indirectly on top of at least one polymer foam insulation board layer; the flame retardant fabric shield having a water vapor transmission rate of 1.0 perm or greater.

[0044] In some other embodiments, the present invention also relates to a flame retardant fabric protective cover, which includes a non-woven felt of short fibers. The non-woven felt has a water vapor permeability of 1.0 perm or greater, 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 comprises:

[0045] i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and

[0046] ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

[0047] In some embodiments, the nonwoven 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.

[0048] It should be understood that any and all features, options and elements described herein with respect to the fire retardant fabric shield are equally applicable to the fire retardant fabric shield as used in an inverted roof element assembly and the fire retardant fabric shield article itself.

[0049] In some specific embodiments, the present invention is directed to an inverted roof element assembly comprising a flame retardant fabric shield comprising a staple fiber mat having a water vapor transmission rate of 1.0 perm or greater, a basis weight of about 150 to 800 grams per square meter, and a thickness of about 1.5 to 6.0 mm; and

[0050] i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and

[0051] ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

[0052] In some embodiments, the felt of the flame retardant fabric shield has a basis weight of about 150 to 400 grams per square meter and a thickness of about 1.5 to 4.0 mm.

[0053] In some further embodiments, the flame retardant fabric protective cover comprises:

[0054] i) 40 to 80 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and

[0055] ii) 20 to 60 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

[0056] In some embodiments, at least 40 weight percent of the total amount of staple fibers of the flame resistant fabric shield are long staple crimped staple fibers.

[0057] It is believed that the flame retardant fabric shield should have a water vapor transmission rate of 1 perm or greater to ensure that the structure does not accumulate water after exposure to rain, but rather allows the structure to dry itself. In some embodiments, the flame retardant fabric shield has a water vapor transmission rate of 10 perm or less; higher values ​​are believed to provide excessive fabric openness, which may not function as a flame retardant fabric shield.

[0058] In some embodiments, the flame retardant fabric shield is a nonwoven felt. Nonwoven felt means a conventional felt structure achieved by consolidating short fiber batts typically via needle punching or hydroentanglement. Needle punching processes such as disclosed in U.S. Pat. Nos. 2,910,763 and 3,684,284, and hydroentanglement (hydrolacing or spunlacing) processes such as disclosed in U.S. Pat. No. 4,556,601 to Kirayoglu describe methods known in the art for making nonwoven felts. Preferably, the nonwoven felt is a needle punched felt.

[0059] As used herein, the term "staple fiber" refers to fibers made by cutting filaments into lengths not exceeding about 15 cm (5.9 inches), preferably 3 to 15 cm (1.2 to 5.9 inches), and most preferably 3 to 8 cm (1.2 to 3.1 inches). Staple fibers can be straight (i.e., non-curled) or curly to have a zigzag curl along its length, with any frequency of curl (or repeated bends).

[0060] As used herein, the term "recycled" meta-aramid staple fibers means meta-aramid staple fibers derived from filament raw materials or other fiber sources that are generally considered waste and treated as waste; these "recycled" meta-aramid staple fibers may have as their source at least one of the following categories that produce meta-aramid filaments and meta-aramid fiber waste:

[0061] i) spinning machine filament waste, i.e. filament that has been spun but not packaged for primary sale, which is considered and treated as waste; this includes filament waste generated during spinning machine start-up and shut-down, and general spinning machine waste generated during spinning machine breakdowns;

[0062] ii) filaments that have been spun and wound into packages but have defects and are considered and handled as waste; these include filaments with unacceptable uniformity (such as denier or color variation); filaments with mechanical or structural defects, and filaments with unacceptable amounts of spin finish or lack of spin finish, making them generally unsuitable for subsequent normal processing;

[0063] iii) bobbin tails, which are the filaments that remain on the bobbin after a certain length of yarn has been used from the bobbin and which do not have sufficient length so that they must be disposed of as waste;

[0064] iv) fibrous materials resulting from the deconstruction of woven or knitted fabrics during a fabric recycling process; and

[0065] v) Fiber materials recovered from recycled articles and other recycled materials.

[0066] Depending on the source, "recycled" meta-aramid staple fibers may or may not have crimp and may or may not be precisely cut. For example, filament and bobbin tails that have been spun and wound into packages but have defects and are considered waste and handled as waste may be of sufficient quality that they can be crimped and precisely cut.

[0067] In some embodiments, the nonwoven felt that is a flame retardant fabric protective cover consists essentially of meta-aramid staple fibers as described herein. As used herein, "consisting essentially of" with respect to a fiber blend is intended to mean that the fiber blend may additionally include up to about 5 percent of additional materials or fibers that do not significantly affect the performance of the nonwoven felt.

[0068] Useful meta-aramid-containing fibers, including fibers containing poly(meta-phenylene isophthalamide) (MPD-I), have a limiting oxygen index (LOI) of about 26 or more. This means that the meta-aramid staple fibers preferably provide the nonwoven felt with fibers that do not burn in air. The limiting oxygen index (LOI) is the minimum concentration of oxygen that will support the combustion of a polymer, expressed as a percentage. It is measured by passing a mixture of oxygen and nitrogen over a burning sample and reducing the oxygen level until a critical level is reached. The LOI values ​​of different plastics are determined by standardized tests such as ISO 4589 and ASTM D2863. Air nominally contains about 21 percent oxygen, so materials with an LOI value of less than 21 are classified as combustible materials, but materials with an LOI greater than 21 are classified as self-extinguishing materials because they cannot continue to burn at ambient temperature without external energy contribution. If a blend of meta-aramid staple fibers and other fibers is present in the felt, it is believed that the other fibers should also preferably have an LOI of at least 24. In some embodiments, the felt further comprises up to 80 weight percent of staple fibers having a limiting oxygen index (LOI) of 24 or higher based on the total amount of staple fibers present in the felt. Specifically, the other staple fibers can be crimped staple fibers, in particular crimped virgin staple fibers made from materials having a LOI of 24 or higher. Preferably, all fibers or fiber materials in the nonwoven felt or flame retardant fabric shield have a LOI of 24 or higher.

[0069] The use of recycled meta-aramid staple fibers in the nonwoven felt of the flame retardant fabric shield provides several benefits. For example, the use of these fibers avoids disposing of these fibers as waste, which reduces the number of fibers sent to landfills, which is beneficial to the environment. An additional benefit is that the use of these fibers helps to reduce the overall cost of the felt. Another benefit is that the requirements for the flame retardant fabric shield application 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 are 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 are 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 are recycled meta-aramid staple fibers. In some other embodiments, the total amount of meta-aramid staple fibers in the nonwoven felt that are recycled meta-aramid staple fibers is 70 weight percent or less.

[0070] In some embodiments, at least some percentage of the meta-aramid staple fibers of the reuse have variable cutting lengths. Due to various waste filament sources, all filament raw materials for the meta-aramid staple fibers of the reuse may not be able to be curled and cut via a normal staple cutting process. For example, filaments and bobbin tail yarns that have been spun and wound into packages but have defects can usually be cut into staple fibers using conventional curling / cutting processes, provided that the meta-aramid filaments are curled with uniform cutting lengths. However, spinning machine filament waste and the fibers produced by fabric deconstruction are usually collected as a large amount of filaments, which makes them unsuitable for conventional curling / cutting processes. These filaments can be cut into staple fibers using a paper cutter or other types of shredding operations alternatively; however, these staple fibers are not curled, and the cutting length is not strictly controlled, thereby providing a meta-aramid staple fiber with a variable cutting length. In some embodiments, at least 20 weight percent of the recycled meta-aramid staple fibers have variable cut lengths; in some embodiments, the amount of recycled meta-aramid staple fibers having variable cut lengths is 60 weight percent or less.

[0071] Thus, the recycled meta-aramid staple fibers may include variable cut length recycled meta-aramid staple fibers and precise cut length recycled meta-aramid staple fibers. In some embodiments, the variable cut length recycled meta-aramid staple fibers do not have curl, and the precise cut length recycled meta-aramid staple fibers do have curl.

[0072] While it is advantageous to use recycled meta-aramid staple fibers in nonwoven mats, there may be circumstances where it may be desirable to additionally use meta-aramid staple fibers other than recycled meta-aramid staple fibers in nonwoven mats to improve uniformity. That is, since recycled meta-aramid staple fibers are produced from filament raw materials that are typically considered waste and disposed of as waste, the variability of recycled meta-aramid staple fibers will be higher than meta-aramid staple fibers made from commercially marketable meta-aramid filaments.

[0073] Thus, 0 to 80 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt are crimped virgin meta-aramid staple fibers with uniform cut length. In some embodiments, 0 to 75 weight percent of the total amount of meta-aramid staple fibers in the nonwoven felt are crimped virgin meta-aramid staple fibers with uniform cut length.

[0074] As used herein, the use of the term "virgin" with respect to fibers (including staple fibers) means that the fibers are virgin; that is, they have not been previously used in some application or textile or other article, and otherwise such fibers are not considered to be recycled fibers as described herein. These virgin fibers generally have some predictable structural uniformity and suitable qualities so that they can be used or sold as fibers in applications that require or desire virgin fibers; such applications would then use these virgin fibers for the first time in textile yarns, fabrics, and other structures.

[0075] In addition, as used herein, the phrase "crimped virgin meta-aramid staple fibers having uniform cut lengths" means meta-aramid staple fibers that are specifically manufactured, crimped, cut, and commercially sold in bales for use as meta-aramid staple fibers in traditional textile applications (yarns, fabrics, nonwovens, etc.), and are not recycled meta-aramid staple fibers. 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.

[0076] If it is desired that both the meta-aramid staple fibers of the recycled material and the curled virgin meta-aramid staple fibers of uniform cut length are present in the nonwoven felt, then preferably, the nonwoven felt is made of a raw material that is a close staple fiber blend of the two types of fibers, which means that the two types of fibers are uniformly mixed together. In addition, if both the meta-aramid staple fibers of the recycled material and the curled virgin meta-aramid staple fibers of uniform cut length are present in the nonwoven felt, then preferably, they are also arranged in the nonwoven felt as a close blend, which means that the two types of fibers are uniformly mixed and distributed in the felt. The uniform mixture in the felt avoids any localized areas with high concentrations of any one type of fiber in any part of the felt.

[0077] In addition, in some embodiments, at least 40 weight percents of the combined staple fiber total amount in the nonwoven felt are curly staple fibers. It is believed that the staple fiber supply with the curly staple fibers less than 50 weight percents will run into more problems in combing and other processing problems, making the generation of nonwoven felt more difficult. In certain embodiments, at least 60 weight percents of the combined staple fiber total amount in the nonwoven felt are curly staple fibers. In some other embodiments, the total amount of the combined staple fibers for curly staple fibers in the nonwoven felt is 75 weight percents or less.

[0078] In some preferred embodiments, the staple fiber with curling has a curling frequency of 2.5 to 5.5 curls / cm (7 to 14 curls / inch); and in some embodiments, both the staple fibers of uniform cut length and variable cut length have curling. In some preferred embodiments in nonwoven felts, the staple fibers including both uniform cut length and variable cut length have a minimum cut length of 1.0 cm (0.4 inch). In some preferred embodiments in nonwoven felts, both staple fibers including both uniform cut length and variable cut length have a maximum cut length of 10.1 cm (4.0 inches). As used herein, "uniform cut length" and "precise cut length" are intended to have the same meaning and can be interchangeable. The staple fibers with uniform cut length are preferably cut into a length of 3.8 to 10.1 cm (1.5 to 4.0 inches). In still other embodiments, the nonwoven felt consists of 60 to 40 weight percent of meta-aramid staple fibers having a uniform or precise cut length and 40 to 60 weight percent of meta-aramid staple fibers having a variable cut length, based on the total amount of combined meta-aramid staple fibers in the nonwoven felt.

[0079] In addition, in some embodiments, at least 20 weight percent of the curly fibers are "long-staple" fibers. As used herein, "long-staple" means curly staple fibers having a cut length of 2.5 to 10.1 cm (1 to 4 inches). In some embodiments, at least 40 weight percent of the total amount of staple fibers of the flame retardant fabric shield are long-staple curly staple fibers. If desired, other fibers such as glass, polyacrylonitrile, mineral wool, or mixtures thereof can be combined with the recycled meta-aramid staple fibers.

[0080] 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 a basis weight of 200 to 400 grams per square meter. In addition, the nonwoven felt also has a thickness of 1.5 mm 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 flame retardant fabric shield, which means that the single-layer nonwoven felt can function as desired in IRMA. However, if desired, the flame retardant fabric shield can include multiple layers of nonwoven felt as described herein. Alternatively, the flame retardant fabric shield may include one or more layers of the nonwoven felts described herein layered with one or more layers of one or more felts having no recycled meta-aramid staple fibers, as long as the flame retardant properties of the IRMA are not reduced by the addition of the other nonwoven felts.

[0081] In some embodiments, meta-aramid staple fibers refer to staple fibers made from filaments of aramid polymers, wherein two rings or groups are oriented meta relative 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 produced by the mole-to-mole polymerization of m-phenylenediamine and isophthaloyl chloride, and also a copolymer produced by the combination of a small amount of other diamines with m-phenylenediamine and a small amount of other diacyl chlorides with isophthaloyl chloride. In general, other diamines and other diacyl chlorides can be used up to about 10 mole percent of m-phenylenediamine or isophthaloyl chloride or possibly slightly higher amounts, provided that the other diamines and diacyl chlorides do not have reactive groups that interfere with the polymerization reaction. Additives can be used to prepare meta-aramid fibers, as long as the nonwoven felt made of such fibers is fully characterized as a flame retardant fabric shield.

[0082] Meta-aramid filaments are typically spun by extruding a solution of a meta-aramid polymer through a capillary and removing the solvent via a dry or wet spinning process as known in the art. In the case of poly(m-phenylene isophthalamide), the solvent for the solution is typically dimethylacetamide. The solvent-containing stock filaments are spun, followed by removal of the solvent and other treatments (such as washing, drying, and optionally heat treatment as known in the art). Some useful methods for preparing meta-aramid fibers are disclosed in, for example, U.S. Patent Nos. 3,063,966 and 5,667,743. Other useful methods for preparing meta-aramid fibers (like fibers containing MPD-I) 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 the use of a spinning unit with a heated gaseous atmosphere for dry spinning of meta-aramid filaments, wherein a heated gas is provided to the spinning unit to remove the solvent. The meta-aramid filaments can then be cut and crimped using conventional techniques to prepare meta-aramid staple fibers.

[0083] Ballast

[0084] The ballast layer is installed directly or indirectly on top of the flame retardant fabric shield. Ballast material is a dense, heavy material that holds the items in the roof assembly (particularly the flame retardant fabric shield and one or more layers of polymer foam insulation) in place by gravity. Ballast material can include coarse or fine granular materials, such as gravel, stone, soil, or planting medium. Ballast can be or include planting media for green roofs or other green roof structures or components of green roof structures. Ballast can be or include blue roof structures or components thereof. Other ballast materials include paving materials of various shapes and sizes, which can form continuous or discontinuous layers. Different ballast materials can be used in any particular roof structure. In some embodiments, the ballast of the inverted roof membrane assembly includes gravel, stone, soil, concrete paving materials, green roof structures or components thereof, or blue roof structures or components thereof.

[0085] If desired, the ballast layer may be mounted indirectly to the fire retardant fabric shield by using other items or layers located between the fire retardant fabric shield and the ballast layer. A particularly useful arrangement is to use a series of pedestals inserted and distributed between the fire retardant fabric shield and the ballast layer to provide support for the ballast layer, such as Figure 1As shown. These pedestals provide improved air circulation over the roof and help reduce heat conduction from the ballast to the roof deck. The pedestals can be made of any material that can properly support the desired ballast material; they are typically made of plastic or metal or a combination thereof, but other materials of construction are possible if desired. Any suitable pedestal arrangement may be used as long as the roof functions as desired.

[0086] Test Method

[0087] Flame performance. The performance of flame retardant fabric shields in roof applications is measured using ASTM E108. ASTM E108 is a fire test response standard used to evaluate roof coverings for materials used on combustible or non-combustible floor decks in both residential and commercial roofs. The evaluation simulates a fire originating from outside the building in conditions accompanied by wind.

[0088] Water Vapor Permeability / Permeance The water vapor permeability (in US Perm-inch) and water vapor transmission rate (in US Perm) of flame retardant fabric protective covers are measured using ASTM E96.

[0089] Trapezoidal Tear Strength. The trapezoidal tear strength (in pounds per square inch) of the flame retardant fabric protective cover is measured using ASTM D4533.

[0090] Tensile Strength / Strain. The tensile strength (in pounds per square inch) and strain (in percent) of flame retardant fabric face coverings are measured using ASTM D882.

[0091] Example 1

[0092] A variety of nonwoven fabric samples in the form of needle felts were made from recycled meta-aramid staple fibers (specifically poly(meta-phenylene isophthalamide) staple fibers) with cut lengths varying from 0.4 to 2.5 inches and precision cut crimped virgin meta-aramid staple fibers (specifically poly(meta-phenylene isophthalamide) staple fibers) with a uniform cut length of 3 inches. Both meta-aramid staple fibers had a linear density of about 2.2 denier. The fiber composition of the fiber supply used to prepare each fabric sample is shown in Table 1.

[0093] Each fiber supply was carded to form a web, which was then cross-lapped to form a batt, which was then needle punched; the batt was first consolidated with a needle punch at a needle density of 75 penetrations / cm2, and then needle punched twice, each with a needle density of 125 penetrations / cm2. The final felt thickness and basis weight are shown in Table 1.

[0094] Table 1

[0095]

[0096] Example 2

[0097] The flame spread performance of the nonwoven fabric articles 3 and 5 of Table 1 was then evaluated using ASTM E108-20a (r2020), "Standard Test Methods for Fire Tests of Roof Coverings". This test plan is based on Section 7.1 of ASTM E108 and is applicable to roof coverings restricted for use over noncombustible floor decking (steel, concrete, or gypsum). The flame spread test is the only test required. The fabric articles of the present invention were tested with The performance of two samples of FR-10 (articles A and B) was compared. FR-10 is a known conventional roof barrier that is specifically designed for installation over wood floor decking or certain combustible insulation materials, which are fiberglass mats with a proprietary fire retardant coating (FR-10 and FR-50 Fire Retardant Slipsheet datasheet, Atlas Roofing Corporation). The test setup and results are shown in Table 2. As shown, the nonwoven fabric of the present invention showed no surface ignition and provided better fire retardant fabric protection than the comparative material.

[0098] Table 2

[0099]

[0100] Example 3

[0101] Nonwoven fabric item 5 of Table 1 (which is a mixture of 60 weight percent recycled MPD-I fibers having different cut lengths (0.4 to 2.5 inches) and 40 weight percent precision cut (3 inches) MPD-I crimped virgin fibers) was further tested to determine other fabric properties, which are summarized in Table 3.

[0102] Table 3

[0103]

[0104]

Claims

1. An inverted roof membrane assembly comprising: a) Suitable for waterproof membranes installed directly or indirectly on top of roof decking, b) at least one layer of polymer foam insulation board directly or indirectly on top of a), c) a flame retardant fabric shield directly or indirectly on top of b), the flame retardant fabric shield having a water vapor transmission rate of 1.0 perm or greater; and d) A ballast layer directly or indirectly on top of c).

2. The inverted roof membrane assembly according to claim 1, wherein: The flame retardant fabric shield is a nonwoven felt.

3. The inverted roof membrane assembly according to claim 2, wherein: The nonwoven felt is a needle-punched felt.

4. The inverted roof membrane assembly according to any one of claims 1 to 3, wherein: The flame retardant fabric shield comprises a staple fiber mat having: 1.0perm or greater water vapor transmission rate, A basis weight of about 150 to 800 g / m2, and Thickness of about 1.5 to 6.0 mm; in: i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

5. The inverted roof membrane assembly according to claim 4, wherein: The felt has a basis weight of about 150 to 400 g / m2 and Thickness of about 1.5 to 4.0 mm.

6. The inverted roof membrane assembly according to claim 4 or 5, wherein: The felt further comprises up to 80 weight percent of staple fibers having a limiting oxygen index of 24 or greater, based on the total amount of staple fibers present in the felt.

7. The inverted roof membrane assembly according to any one of claims 4 to 6, wherein: At least 40 weight percent of the total amount of the staple fibers of the flame resistant fabric shield are crimped staple fibers.

8. The inverted roof membrane assembly according to any one of claims 4 to 7, wherein: The flame retardant fabric protective cover comprises: i) 40 to 80 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and ii) 20 to 60 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

9. The inverted roof membrane assembly according to any one of claims 1 to 8, wherein: The polymer foam insulation board has a maximum 3 (3.5 lbs / cubic foot) foam density, at least 0.6 cm (0.25 in) thickness, at least 0.53 K·m 2 / W / RSI value of 25.4mm thickness (3.0F°·ft 2 h / BTU / inch thickness of R-value).

10. The inverted roof membrane assembly according to claim 9, wherein: The foamed polymer foam insulation board has a thermal conductivity of 21 to 56 kg / m 3 Foam density and thickness from 3 to 5 inches.

11. An inverted roof membrane assembly as claimed in any one of claims 1 to 10, wherein b) comprises at least two layers of said polymer foam insulation board directly or indirectly on top of layer a).

12. The inverted roof membrane assembly according to any one of claims 1 to 11, wherein: The ballast includes gravel, stone, soil, one or more paving materials, a green roof structure or components thereof, or a blue roof structure or components thereof.

13. A flame retardant fabric protective cover comprising a nonwoven felt of staple fibers, the nonwoven felt having 1.0perm or greater water vapor transmission rate, A basis weight of about 150 to 800 g / m2, and Thickness of about 1.5 to 6.0 mm; in: i) 20 to 100 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and ii) 0 to 80 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

14. The flame retardant fabric protective cover of claim 13, wherein: The felt has a basis weight of about 150 to 400 g / m2 and Thickness of about 1.5 to 4.0 mm.

15. The flame retardant fabric protective cover according to claim 13 or 14, wherein: The nonwoven felt is a needle-punched felt.

16. The flame retardant fabric protective cover according to any one of claims 13 to 15, wherein: The felt further comprises up to 80 weight percent of staple fibers having a limiting oxygen index of 24 or greater, based on the total amount of staple fibers present in the felt.

17. The flame retardant fabric protective cover according to any one of claims 13 to 16, wherein: At least 40 weight percent of the total amount of the staple fibers of the flame resistant fabric shield are crimped staple fibers.

18. The flame retardant fabric protective cover according to any one of claims 13 to 17, wherein: i) 40 to 80 weight percent of the total amount of staple fibers is recycled meta-aramid staple fibers; and ii) 20 to 60 weight percent of the total amount of staple fibers are crimped virgin meta-aramid staple fibers having uniform cut length.

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