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US 20110070419A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2011/0070419 A1 Lim et al. (43) Pub. Date: Mar. 24, 2011

(54) NONWOVEN FIRE BARRIER WITH Publication Classification ENHANCED CHAR PERFORMANCE (51) Int. Cl. (76) Inventors: Sang-Hoon Lim, Kennesaw, GA D04H 3/12 (2006.01) (US); Andrea Piana, Atlanta, GA D04H 3/4 (2006.01) (US s s D04H 3/10 (2006.01) 52) U.S. Cl...... 428/219: 442/414 (21) Appl. No.: 12/817,775 (52) s (22) Filed: Jun. 17, 2010 (57) ABSTRACT O O and/or , when combined with flame Related U.S. Application Data retardant (FR) cellulosic fiber, forms a nonwoven fire barrier (60) Provisional application No. 61/243,580, filed on Sep. with enhanced fire barrier performance, such as char elonga 18, 2009. tion and char strength. US 2011/0070419 A1 Mar. 24, 2011

NONWOVEN FIRE BARRIER WITH woven fire barriers with superior fire resistant properties to ENHANCED CHAR PERFORMANCE that afforded by a FR-treated and , but which remain cost effective making them suitable for use in CROSS-REFERENCE TO RELATED mattresses, upholstered furniture, and in other applications. APPLICATIONS 0001. This application claims priority to U.S. Provisional SUMMARY Patent Application 61/243,580 filed on Sep. 18, 2009, which 0008. An exemplary embodiment of the present invention is herein incorporated by reference. is a nonwoven fire barrier containing one or more FR cellu losic fibers and one or more performance-enhancing fibers, FIELD OF THE INVENTION such as basalt fibers or glass fibers. The uses of the nonwoven 0002 The present invention is related to a nonwoven fire fire barrier include, but are not limited to, mattresses, furni barrier comprised of a blend of fibers. More particularly, the ture, building insulations, automotive, appliances, and wall main components of the nonwoven fire barrier are flame panels for cubicles. retardant (FR) cellulosic fiber and performance-enhancing 0009. According to the invention, the addition of basalt fiber, which is basalt fiber, glass fiber, or a mixture of these. fiber, glass fiber, or a mixture of these to FR cellulosic fibers The nonwoven fire barrier produced is cost-effective and has can dramatically improve the fire barrier performance. Such a variety of uses including without limitation use in mat as char strength and char elongation, which are critical prop tresses and upholstered furniture. erties of fire barrier nonwoven materials. BACKGROUND DETAILED DESCRIPTION 0003. There has been an increasing demand for fire barrier 0010. The present invention generally relates to nonwoven products for use in mattresses and upholstered furniture. For composition which contains FR cellulosic fiber(s) and per example, the new U.S. federal open-flame mattress standard formance-enhancing fiber, such as basalt fiber, glass fiber, or (CPSC 16 CFR Part 1633) has created a new demand for a mixture of these. flame retardant (FR) fibers in the mattress industry. A number 0011 Basalt is a common extrusive volcanic rock. The of companies have been developing nonwoven fire barriers to manufacture of basalt fiber requires the melting of the quar meet the federal standard. Examples of the approaches now ried basalt rock to about 2,730° F. The molten rock is then being used are described in the following recently issued extruded through small nozzles to produce continuous fila patents. ments of basalt fiber. The filaments are cut to desired length 0004 U.S. Pat. No. 7,410,920.(Davis) describes a non depending on final uses. Due to its Superior thermal, physical, woven fire barrier consisting of charring-modified viscose and chemical properties, it is often used for insulation, con fibers (Visil.R.) with less than 5% of polymers made from struction, automotive, and aircraft applications. halogenated monomers. 0012 A“nonwoven' is a manufactured sheet, web, or batt 0005 U.S. Pat. No. 7.259,117 (Mater et al.) discloses a of natural and/or man-made fibers or filaments that are nonwoven high-loft fire barrier for mattresses and uphol bonded to each other by any of several means. Manufacturing stered furniture. The high-loft nonwoven is composed of of nonwoven products is well described in “Nonwoven Tex melamine fiber alone or in conjunction with other fibers. tile Fabrics’ in Kirk-Othmer Encyclopedia of Chemical 0006. There are a number of manufactured FR fibers, i.e., Technology, 3rd Ed., Vol. 16, Jul. 1984, John Wiley & Sons, FR compound is added to polymer dope and extruded such p. 72-124 and in “Nonwoven ', Nov. 1988, Carolina that, for example, the polymer backbone is modified to give Academic Press. Web bonding methods include mechanical flame retardancy. Manufactured FR fibers include bonding (e.g., needle punching, Stitch, and hydro-entangle (NomexR) and .R.), polyimide fibers (UltemR) poly ment), chemical bonding using binder chemicals (e.g., Satu etherimide and ExtemR amorphous thermoplastic polyimide ration, spraying, screen printing, and foam), and thermal fibers), melamine fiber (Basofil(R), halogen-containing fibers bonding using binder fibers with low-melting points. Two (Saran R fiber, modacrylics), polyphenylene sulfide fibers common thermal bonding methods are air heating and calen (Diofort(R), oxidized polyacrylonitrile fibers (Pyron(R), cured daring. In air heating, hot air fuses low-melt binder fibers phenol-aldehyde fibers (KynolR novoloid fiber), phospho within and on the surface of the web to make high-loft non rous FR-containing rayon fibers (Lenzing FRR), Shangdong woven. In the calendaring process, the web is passed and Helon's Anti-frayon R, and silica-containing rayon fibers (Vi compressed between heated cylinders to produce low-loft sil(R), Daiwabo’s FR CoronaRfibers, Sniace’s FR fiber, and OWOW. Shangdong Helon's Anti-fcell R. 0013. In the practice of this invention, the fire barrier mate 0007. Despite their advantages, manufactured FR fibers rial is a nonwoven made from FR cellulosic fiber and perfor are expensive. From an economic perspective, most of them mance enhancing fiber selected from basalt and glass fibers. are not suitable for mattresses and upholstered furniture due In addition, other fibers (optional fibers) may be included in to their high costs. For the mattress and upholstered furniture the nonwoven to achieve properties or characteristics of inter industries, the most cost-effective commonly available FR est (e.g., color, texture, etc.). The nonwoven may be made cellulosic fibers are FR-treated cotton fiber and FR-treated using mechanical bonding, chemical bonding, or thermal rayon fiber that are produced by post FR chemical treatment bonding techniques. In an exemplary embodiment, thermal of cotton and rayon fibers. Examples of FR cellulosic fibers bonding using low melting point fibers (low-melt binder are commercially available from Tintoria Piana US, Inc. fiber) is employed to manufacture the nonwoven (i.e., the low (Cartersville, Ga., USA). The char forming property of these melting point fibers melt at a lower temperature than the FR-treated cotton and rayon-fibers make them suitable for decomposition temperature of FR cellulosic fibers and the fire barrier; however, it would be advantageous to have non melting point temperature of the performance enhancing US 2011/0070419 A1 Mar. 24, 2011

fibers, and, after melting and diffusion into the fibers, serve to chemical treated to increase flame retardancy. As optional hold the FR cellulosic fibers and performance enhancing fiber addition, any of these fibers or any combination of these fibers together in the nonwoven). The low-melt binder fibers can be added. Man-made fibers include, but are not limited to, can be-any of those commonly used for thermal bonding and , , acrylics, acetate, polyolefins, melamin may preferably, but are not limited to, those that melt from 80 fibers, elastomeric fibers, polybenzimidazole, fibers, to 150°C. The nonwoven preferably has a basis weight of a polyimide fibers, modacrylics, polyphenylene sulfide fibers, basis weight ranging from 0.1-5.0 oz/ft (more preferably, , Novoloid fibers, manufactured cellulosic fibers 0.32-2.0 oz/ft; however, the basis weight of the nonwoven (rayon, , fiber, tencel(R), and modal(R), and can vary widely depending on the intended application and manufactured FR cellulosic fibers (e.g., Visil(R), Anti-fcellR), desired characteristics of the nonwoven. Daiwabo’s FR CoronaR) fibers, Anti-frayon R, Sniace’s FR Component 1 (Main Component): FR Cellulosic Fiber rayon, and Lenzing FR(R). Natural fibers include, but are not limited to, cotton, , , , abaca, , kapok, , 0014 FR cellulosic fiber includes FR-treated natural cel , , coconut fiber, pineapple fiber, , cashmere, lulosic fiber, FR-treated manufactured cellulosic fiber, manu and . factured FR cellulosic fiber, or a mixture of any combination of these fibers. FR chemicals for FR treatment include, but are 0018. The principle constituents of the nonwoven fire bar not limited to, phosphorus-containing FR chemicals, Sulfur rier are components 1 and 2. The preferred amount of com containing FR chemicals, halogen-containing FR chemicals, ponent 1 (FR cellulosic fiber) is approximately 5-99.99 wt.% antimony-containing FR chemicals, and boron-containing and more preferably 50-99.99 wt.%. The preferred amount FR chemicals. Examples of FR chemicals include, but not of component 2 (performance-enhancing fiber) is approxi limited to, phosphoric acid and its derivatives, phosphonic mately 0.01-95 wt.% and more preferably at 0.01-50 wt.% acid and its derivatives, Sulfuric acid and its derivatives, Sul or 0.01-20 wt.% famic acid and its derivatives, boric acid and its derivatives, 0019. In exemplary embodiments, for thermal bonded borax, borates, ammonium phosphates, ammonium poly nonwovens, component 3 (low-melt binder fiber) is required. phosphates, ammonium sulfate, ammonium Sulfamate, However, for needle-punched and chemical-bonded nonwov ammonium chloride, ammonium bromide. Natural cellulosic ens, component 3 is optional. The preferred amount of com fiber includes, but not limited to, cotton, kapok, flax, ramie, ponent 3 is approximately 1-70 wt.% and more preferred at kenaf, abaca, coir, hemp, jute, sisal, and pineapple fiber. 5-50 wit. 9%. Manufactured cellulosic fiber includes, but not limited to, 0020. Those of skill in the art will recognize that the pre rayon, lyocell, bamboo fiber, Tencel(R), and Modal(R). Manu ferred amounts of components of 1, 2, and 3 are not limited to factured FR cellulosic fiber includes, but not limited to, Len the ranges specified above, and that, depending on the appli zing FRR), Anti-frayon R, Anti-fcell R, Visil R., Daiwabo’s FR cation, manufacturing process, or other conditions, the Corona R fibers, and Sniace’s FR rayon. amounts of components 1, 2 and 3 can be varied considerably Component 2 (Main Component): Performance-Enhancing within the practice of this invention. Fiber 0021 Component 4 can be optionally added to the blend for providing desired characteristics (e.g., softness, texture, 00.15 Performance-enhancing fiber includes basalt fiber, appearance, resilience, etc.) or cost benefit. Components 1 glass fiber, or a mixture these fibers. Glass fiber includes any through 4 are blended at different ratios depending on final type of glass fibers. Such as A-glass, E-glass, S-glass, C-glass, use and cost of the nonwoven. For example, to provide better T-glass, AR-glass, etc. resilience property on the final high-loft, nonwoven product and cost benefit, polyester fiber (as component 4) can be Component 3: Low-Melt Binder Fiber (or Powdered Poly added to the blend. One possible example of blend ratio will mer) be FR cellulosic fiber:basalt fiber:polyester fiber:low-melt 0016 Low-melt binder fibers are synthetic fibers and are binder fiber 40-70:5-20:5-20:10-30, e.g., 60:10:10:20. most widely used for thermal bonded nonwoven materials, although sometimes powdered polymers are used in thermal EXAMPLE 1. bonding. Any type of low-melt binder fibers used for thermal bonding process can be used for this application. These syn 0022. Nonwoven web samples with different fiber com thetic fibers can be either a bicomponent fiber or a fiber with positions were prepared using a lab carding machine. For the low melting point. Low-melt binder fiber is optional for samples, FR chemical (ammonium phosphate) treated rayon needle punched nonwoven and chemical-bonded nonwoven. fiber, FR chemical (ammonium phosphate) treated cotton For chemical bonding, binders include, but are not limited to, fiber, basalt fiber (diameter: 13 lum, length: 90 mm), glass acrylic latexes, poly Vinyl acetate copolymer, poly vinyl chlo fiber (E-glass, diameter: 13um, length: 90mm), and low-melt ride copolymer, ethylene vinyl chloride, vinyl acetate-ethyl binder fiber (LM) were used. For a fair comparison, the total ene, acrylic copolymer, butadiene-acrylonitrile copolymers, weight of each blend was controlled to be the same at 10 acrylic binders, styrene acrylonitrile binder, styrene butadi grams. ene rubber binder, etc. 0023 The samples were completely burned to form a char using a burner horizontally located beneath the samples. Char Component 4: Optional Fiber strength and elongation were measured by a chartester. The 0017 Optional fiber in the practice of this invention is tester is equipped with a loadcell connected to a vertically additional fiber(s) added to the blend to provide desired char movable plate which presses char until its breakage. Elonga acteristics or cost benefits. Optional fiber includes man-made tion was measured in the unit of inches and char strength was fibers and natural fibers. These fibers can be untreated or FR measured as peak force in the unit of pounds (1b). US 2011/0070419 A1 Mar. 24, 2011

help to prevent possible char breakage under severe flame TABLE 1. conditions which would otherwise cause further flame propa gation. Effect of Basalt and glass fibers on FR-treated rayon fiber Elongation Peak EXAMPLE 2 Fiber blends (wt.%) (inch) force (Ib) 0025. Thermal bonded high-loft nonwoven samples were FR-treated rayon:LM = 80:20 O.359 4.21 FR-treated rayon:basalt fiber:LM = 70:10:20 O.609 12.24 prepared by using a commercial production line. FR Cellu FR-treated rayon:glass fiber:LM = 70:10:20 O.639 12.53 losic fibers and low-melt binder fiber (LM) with/without basalt fiber were blended at specific wt.% ratios. The blended fibers were carded to form a fiber web on a conveyor. The web is cross-lapped and passed through an oven to form a high-loft TABLE 2 nonwoven. Various blend samples were prepared at different basis weight expressed as ounce per square foot (oz/ft). The Effect of basalt and glass fibers on FR-treated cotton fiber nonwoven samples were tested for char elongation and Elongation Peak strength by the same method described in Example 1. Fiber blends (wt.%) (inch) force (Ib) 0026 Table 3 shows char properties of FR cellulosic high FR-treated cotton:LM = 80:20 O.317 1.47 loft nonwovens which can be used, for example, in the mat FR-treated cotton:basalt fiber:LM = 70:10:20 0.735 6.83 tress industry. All these nonwovens show char elongation FR-treated cotton:glass fiber:LM = 70:10:20 O640 6.55 below 0.4 inch and char strength below 2 lbs, which are pretty common for those products. Table 4 shows performance of 0024. As demonstrated in Tables 1 and 2, the char elonga Some examples of the invented nonwoven blends containing tion and char strength of FR-treated cotton and FR-treated basalt fiber (diameter: 13 lum, length: 90 mm). The results rayon fibers increased dramatically by adding only 10% of demonstrate significant increases in both char elongation and basalt or glass fiber. This improved char performance will strength by the addition of basalt fiber.

TABLE 3 Properties of high-loft nonwoven made with FR cellulosic fibers and low-melt binder fiber (LM). Weight of Elongation Peak force Fiber blends (wt.%) nonwoven (oz/ft) (inch) (1b) Visi (R):LM = 80:20 O.80 O.365 O.92 FR-treated rayon":Visil (R):LM = 40:40:20 O.77 O.334 1.10 FR-treated cotton':Visil (R):LM = 40:40:20 O.80 O352 O.60 FR-treated rayon":FR-treated cotton':LM = 40:40:20 O.81 O.244 1.13 FR-treated rayon":FR-treated cotton':LM = 40:40:20 1.01 O.284 1.23 FR-treated rayon?:LM = 80:20 O.80 O.210 1.OS FR-treated cotton’:Anti-fcell (R):LM = 40:40:20 1.13 O.336 O.86 'FR treatment with ammonium phosphate *FR treatment with ammonium sulfate

TABLE 4 Properties of high-loft nonwoven made with FR cellulosic fibers, basalt fiber, and low-melt binder fiber (LM). Weight of Elongation Peak force Fiber blends (%) nonwoven (oz/ft) (inch) (1b) FR-treated cotton':basalt:LM = 60:10:30 OSO O.425 4.6O FR-treated cotton':basalt:LM = 60:10:30 O.76 O600 8.33 FR-treated cotton':basalt:LM = 60:10:30 O.90 O641 9.65 FR-treated cotton':basalt:LM = 55:15:30 OSO O.S13 6.OS FR-treated cotton':basalt:LM = 55:15:30 O.76 O.S48 1428 FR-treated cotton':basalt:LM = 55:15:30 O.92 O.S94 16.61 FR-treated cotton':FR-treated cotton shoddy'*:basalt:LM = O.S8 O.476 10.78 30:25:15:30 FR-treated cotton':FR-treated cotton shoddy'*:basalt:LM = O.80 O689 13.39 30:25:15:30 FR-treated cotton':FR-treated cotton shoddy'*:basalt:LM = O.91 O.714 1853 30:25:15:30 FR-treated cotton':FR-treated cotton shoddy'*:basalt:LM = O.99 O.834 1997 30:25:15:30 'FR treatment with ammonium sulfate *Cotton shoddy is recycled cotton fiber from waste. US 2011/0070419 A1 Mar. 24, 2011

0027. Having thus described the invention in rather full 10. The nonwoven of claim 1 wherein detail, it will be understood that such detail need not be said flame retardant FR cellulosic fiber is FR-treated natu strictly adhered to, but that additional changes and modifica ral cellulosic fiber, FR-treated manufactured cellulosic tions may suggest themselves to one skilled in the art, all fiber, manufactured FR cellulosic fiber, or any combina falling within the scope of the invention as defined by the tion of these fibers, Subjoined claims. said performance-enhancing fiber is basalt fiber, glass fiber, or a mixture of basalt fiber and glass fiber, and What is claimed is: said flame retardant FR cellulosic fiber and said perfor 1. Nonwoven, comprising: mance-enhancing fiber are present in said nonwoven at flame retardant (FR) cellulosic fiber; and approximately 5-99.99 wt.% and 0.01-95 wt.%, performance-enhancing fiber. respectively. 2. The nonwoven of claim 1, wherein the FR cellulosic 11. The nonwoven of claim 10 wherein said FR cellulosic fiber is FR-treated natural cellulosic fiber, FR-treated manu fiber is present in said nonwoven at approximately 50-99.99 factured cellulosic fiber, manufactured FR cellulosic fiber, or wt.%. 12. The nonwoven of claim 10 wherein said performance any combination of these fibers. enhancing fiber is present in said nonwoven at approximately 3. The nonwoven of claim 1, wherein the performance O.O1-20 Wt. 9%. enhancing fiber is basalt fiber, glass fiber, or a mixture of 13. The nonwoven of claim 10 further comprising a low basalt fiber and glass fiber. melt binder fiber at approximately 1-70 wt.%. 4. The nonwoven of claim 1, further comprising a low-melt 14. The nonwoven of claim 13 further comprising a poly binder fiber for thermal bonding of the nonwoven ester fiber. 5. The nonwoven of claim 1, wherein the FR cellulosic 15. The nonwoven of claim 1 wherein fiber and performance-enhancing fiber are mechanically said flame retardant FR cellulosic fiber is FR-treated natu bonded together. ral cellulosic fiber, FR-treated manufactured cellulosic 6. The nonwoven of claim 1, wherein the FR cellulosic fiber, manufactured FR cellulosic fiber, or any combina fiber and performance-enhancing fiber are chemically tion of these fibers, bonded together. said performance-enhancing fiber is basalt fiber, glass 7. The nonwoven of claim 1, further comprising one or fiber, or a mixture of basalt fiber and glass fiber, and said more optional fibers which are different from said FR cellu performance-enhancing fiber is present in said non losic fiber and said performance enhancing fiber. woven at approximately 0.01-20 wt.%. 8. The nonwoven of claim 7 wherein said optional fibers 16. The nonwoven of claim 15 further comprising low-melt are present in Sufficient quantity to provide a characteristic to binder fibers. said nonwoven selected from the group consisting of Soft 17. The nonwoven of claim 15 further comprising one or ness, texture, appearance, resilience, and cost benefit. more optional fibers. 9. The nonwoven of claim 1 wherein said nonwoven has a basis weight ranging from 0.1-5.0 oz/ft.