WO2006110718A2 - Needle punched flame retardant materials - Google Patents

Abstract

The present invention relates to a flame retardant textile structure which may be needle punched into a filler cloth or to foam. The present invention also relates to a mattress or upholstered article which may include a flame retardant textile structure which may be needle punched into a filler cloth or to foam.

Description

NEEDLE PUNCHED FLAME RETARDANT MATERIALS

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/669,421, filed April 8, 2005, the teachings of which are incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to needle punching a flame retardant material to textile structures or foam material. More particularly, the present invention relates to needling a flame retardant material to mattresses filler cloth or mattress foam materials.

BACKGROUND

The U.S. Fire Administration reported in its March 2002 issue (Vol.2, Issue 17) that an estimated 20,800 fires are attributed to mattress/bedding fires causing approximately 380 fatalities each year. To prevent these hazards and others associated with upholstered goods in the home and various institutions, flame retardant materials have been incorporated into mattresses and upholstery to reduce the hazards of open flame and other incendiary exposure.

There are a number of methods to incorporate flame retardant materials into mattresses and upholstered goods. Single or blended fibers, including flame retardant fibers, may be blended into a single layered sheet structure through processes such as air-laying, carding, needle punching or spunbonding. Other times, multiple layers of single or blended fibers may be joined together to create a sheet structure. It is then possible to cover or laminate flame retardant fabrics to the various mattress panels or to upholstered pieces; particularly in areas which are susceptible to exposure. It is also possible to directly treat the fabrics with flammable materials with flame retardant additives or treatments, instead of, or in addition to incorporating flame retardant fibers into the sheet structures.

SUMMARY An exemplary embodiment of the present invention relates to a flame retardant textile composite comprising a filler cloth and a flame retardant material needle punched to the filler cloth. Another exemplary embodiment of the present invention relates to a flame retardant textile composite comprising viscoelastic foam, and a flame retardant material needle punched into the foam.

Another exemplary embodiment of the present invention relates to a mattress comprising a filler cloth, and a flame retardant material needle punched into the filler cloth.

A further exemplary embodiment of the present invention relates to a mattress comprising foam, and a flame retardant material needle punched into the foam.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 illustrates an embodiment of the present invention relating to the response of viscoelastic foam.

DETAILED DESCRIPTION

The present invention relates to needle punching a flame retardant material to textile or foam structures. More specifically, the present invention relates to needling a flame retardant material to mattress filler cloth or foam.

The flame retardant material may be any woven or nonwoven fabric. Where a fabric may be woven, it may be knit or stitched together. In the case of a nonwoven, the nonwoven may be composed of an assembly of textile fibers held together by either mechanical interlocking the fibers, fusing the fibers together or bonding the fibers using a binding material.

The fabric may be composed of fibers including thermoplastic and thermosetting fibers. The fibers may include glass, asbestos, carbon, polyphenylene benzobisoxazole, polybenzimidazole, para-aramids, meta-aramids, fluorocarbons, polyphenylene sulfides, melamines, melamine-formaldehydes, and polyamides. The fibers may also include cellulose-based fibers such as viscose, silicic modified viscose, rayon, cotton, flax, lyocell, ramie, and wood pulp, modacrylics, such as polyacrylonitrile copolymerized with a halogen containing monomer, or pre-oxidized polyacrylonitrile. Furthermore, the fibers included may be combinations of any of the above fibers. It should be appreciated that the flame retardant material may be composed of single or multiple layers of flame retarding materials. Individual layers may be composed of varying combinations of fibers. The layers may also be stitched, mechanically interlocked, fused or bonded together.

Elaborating on the above, the textile structure may be manufactured from a_. combination of modacrylic fiber with a second fiber component which may comprise a viscose fiber containing silicic acid, a regenerated cellulose fiber and/or a melamine formaldehyde polymer, as well as mixtures thereof, and a third fiber component which may comprise an aramid fiber, a melamine/formaldehyde fiber or a polyester fiber and mixtures thereof.

The modacrylic fiber may be based upon a polyacrylonitrile copolymer with a halogen containing comonomer, and the halogen containing comonomer may be polyvinyl chloride) or poly(vinylidine chloride). The modacrylic fiber may be available from Kaneka Corporation, under the trade name Kanecaron™ Protex. The modacrylic employed herein may be sold under the trade name Kanecaron™ Protex PBX, at a specific gravity of 1.45- 1.60 with a fiber denier of 2.2 dtex x 38 mm. Protex PBX is described as having the following chemical components: acrylonitrile, vinylidine chloride copolymer, antimony oxide.

The viscose fiber is a general reference to a fiber produced by the viscose process in which cellulose is chemically converted into a compound for ultimate formation into a fiber material. The viscose fiber may contain silicic acid and may be sold under the trade name Visil™, available from Sateri Oy, Inc. The Visil™ fiber may be type AP 33, 3.5 dtex x 50 mm. It may be composed of 65-75% regenerated cellulose, 25-35% silicic acid and 2-5% aluminum hydroxide. A melamine/formaldehyde fiber component may be sold under the trade name Basofil™, available from McKinnon-Land-Moran, LLC.

The regenerated cellulose fiber is generally a reference to cellulose that is first converted into a form suitable for fiber preparation (e.g. xanthation) and regenerated into the cellulose fiber form. A regenerated cellulose fiber may be prepared from wood pulp, e.g. lyocell fiber.

Expanding on the above, it is worth noting that the preferred use of the lyocell fiber herein is broadly defined as one example of a synthetic fiber produced from cellulosic substances. Lyocell may be obtained by placing raw cellulose in an amine oxide solvent, the solution is filtered, extruded into an aqueous bath of dilute amine oxide, and coagulated into fiber form. From a property perspective, lyocell may also be described as being a relatively soft, strong and absorbent fiber, with excellent wet strength, that happens to be wrinkle resistant, dyable to a number of colors, simulate silk or suede and maintains good drapability. Aramid fiber is reference to an aromatic polyatnide type fiber material, such as a poly(p-phenylene terephthalamide) made by E.I. DuPont de Nemours & Co., sold under the trade name Kevlar^®. The aramid fiber may be present at a level of less than or equal to 60.0% wt., including all percentages and ranges therein.

In addition, the denier of the fibers may be configured ϊn the range of about 1-15 denier, including all increments and ranges therebetween such as between 2-10 denier, 13 denier, or 4-7 denier. The flame retarding material may also have a basis weight of 100-500 g/m , including all increments therebetween at 1 g/m variation. Accordingly, the basis weight of any such fire blocking textile structure disclosed may be in the range of about 100- 350 g/m².

The above referenced fire blocking textile therefore may contain a modacrylic polymer component (e.g., polyacrylonitrile copolymer with poly(vinylidine chloride)) at levels of about 30-80 % (wt.), a second fiber component which may support the modacrylic component may be present at about 10-50 % (wt.) and a third fiber component may be present at a level of about 10-30 % (wt.). In a contemplated embodiment, the modacrylic component may be present at about 70% (wt.) and the second fiber component may be a viscose fiber containing silicic acid and/or a melamine/formaldehyde polymer which may be present at about 20% (wt.). In context of all of these ranges, it should be understood that within the broad scope of this invention, all increments therebetween are included at 1% (wt.) variation.

In another exemplary embodiment of the invention, polymer binder fiber may be added to the textile. Such binder fiber may have the capability to meltbond with the various fiber components. The preferred binder fiber may be a 4d x 2" from either Nan Ya or Sam Yang in Korea. The outer layer may have a melting point of 150°C, which melting point may be lower than the melting point of the inner layer of this particular binder fiber material. The binder fiber outer layer may melt and flow onto the other fibers bonding the structure together. Binder fiber may be added to any of the fiber component combinations herein described.

Elaborating upon the above and in the broad context of the present invention, the binder fibers of the present invention may include one or a plurality of polymer components. In addition, the binder fiber may be in the form of a sheath/core, side by side, or monofilament configuration.

An embodiment of the present invention may generally be described as having a flame retardant component and component supporting said flame retarding component which may be composed of a filler cloth or foam that may be used to reinforce said flame retardant component.

The flame retardant textile component may have a needle-punched textile structure, which may include a first fiber component containing polyacrylonitrile copolymer with a halogen containing monomer; a second fiber component selected from the group consisting of a viscose fiber containing silicic acid, a regenerated cellulose fiber, a melamine/formaldehyde fiber and mixtures thereof; and a third fiber component selected from the group consisting of an aramid fiber, a melamine/formaldehyde fiber, a polyester fiber and mixtures thereof.

In another embodiment, the flame retardant material may include a fire blocking nonwoven textile structure comprising a needle punched web including an aramid fiber, wherein the needle punched web including an aramid fiber may be attached to a spunbond, meltblown or spunbond/meltblown composite web material.

In another embodiment, the flame retardant textile structure may comprise a first carded web including an aramid and/or melamine/formaldehyde fiber; a second carded web comprising a blend of polyacrylonitrile copolymer with a halogen comonomer and a polyester polymer, wherein the first carded web may include aramid and/or melamine/formaldehyde fiber and may be needle punched with the second carded web of said blend.

Another embodiment of the present invention may include a flame retardant textile structure comprising a first carded web including an aramid fiber and/or a melamine/formaldehyde fiber and a second carded web comprising a blend of binder fiber and a polyester polymer, wherein the first carded web contacts the second carded web of the blend.

In connection with the manufacture of the materials herein, containing aramid fiber, it can be noted that given the inherent yellow color of the aramid fiber, it has been found that certain levels of the aramid, will cause the material to similarly yellow, thereby providing an undesirable cosmetic effect for a mattress or upholstered product. Accordingly, it has been found that such undesirable cosmetic feature can be addressed in the flame retarding structure, containing an aramid fiber, wherein the needle punched web including the aramid fiber may be needle punched or otherwise attached to a spunbond, a meltblown web or spunbond/meltblown composite material. Those of skill in the art will recognize that a spunbond web material is a general reference to spun laid technology in which the filaments have been extruded, drawn and laid on a moving belt to form a web. Accordingly, a polymer suitable for the formation of spunbond material may be introduced into an extruder, output to a spinning die, and collected on a web lay down belt and calendar bonded to form a web. In related fashion, a meltblown web material is a general reference to a nonwoven web forming process that extrudes and draws molten polymer resin with heated, relatively high velocity air to form fine filaments. The filaments are cooled and collected as a web onto a moving belt. While similar to the spunbond process, the meltblown fibers tend to be finer and more generally measured in microns. Accordingly, meltblowing is another form of a spunlaid process. Accordingly, the spunbond or meltblown materials suitable for needle punching or otherwise attaching to the aramid based nonwovens of the present invention preferably comprise a poryolefm or polyester based material. More preferably, the polyolefin may be polypropylene. The objective then is to select that amount of spunbond or meltblown material for combining with the aramid based nonwoven web to attenuate the yellow color that is typical for the aramid base web. Accordingly, by attaching a spunbond or meltblown to the aramid based nonwoven web, the yellow color of the aramid based web may be whitened to provide a more cosmetically pleasing resultant product.

In a related embodiment to the above, it has also been found that one may prepare a cosmetically pleasing flame retardant product by first supplying a carded web of an aramid based fiber, e.g., a carded web of aramid with a viscose fiber containing silicic acid (e.g., Visil™). The amount of aramid fiber may be at a level of equal to or greater than 10% (wt), and may be in the range of 10-60% (wt.), including all levels and ranges therebetween. The corresponding amount of viscose fiber may be present at a level between 40-90% (wt.), and at all levels and ranges therebetween. Accordingly, other optional combinations of the first carded web may include 5-25%

(wt.) aramid fiber in combination with 95-75% (wt.) of a viscose fiber containing silicic acid. Furthermore, the first carded web may include 5-25% (wt.) melamine/ formaldehyde fiber in combination with 95-75% (wt.) of a viscose containing silicic acid.

The above may be followed by supplying a second carded web comprising a polyacrylonitrile based composition, which composition may preferably include a blend of polyacrylonitrile copolymer containing a halogen comonomer with a polyester polymer such as PET. In such blend, the polyacrylonitrile copolymer containing a halogen commoner may be present at a level of 70-30 % (wt.) and the polyester may be present at a level of 30-70 % (wt.). Furthermore, the second carded web may include a blend of binder fiber and polyester polymer. The second carded web may also include natural fibers and/or a polyacrylonitrile copolymer with a halogen comonomer. The natural fibers may be composed of wool and/or cotton.

The two carded webs may then be needle punched under conditions wherein the needle punching may be controlled to the point wherein the yellow color of the aramid based carded web may be whitened by the incorporation of the polyacrylonitrile web. One may further needle punch with a spunbond or meltblown web of polyolefin or polyester material.

The flame retardant material may be needle punched onto filler cloth or a foam portion of a mattress or upholstered article. A person of ordinary skill in the art will recognize needle punching as a process for mechanically binding a one or more webs of fiber together to form a fabric. The web(s) may be penetrated by an array of needles carrying tufts of fibers from the web(s) through the web(s).

Filler cloth, as generally referred to herein, may be a material used in areas of a mattress or upholstery that may be removed from the view of the consumer. For example, filler cloth may be found on the underside of a non-flipped mattress or on the upper and bottom portions of a mattress foundation. Filler cloth may also be found on the underside of an upholstered object such as a chair, ottoman or a couch cushion. However, it is also contemplated that filler cloth may be incorporated in any area of an upholstered object or a mattress, including those which may be visible, such as in the upper panels of a mattress or upholstered cushion.

Filler cloth may be composed of a nonwoven thermoplastic material. The thermoplastic material may contain polyester fibers, such as polyethylene terephthalate, polyolefin fibers, such as polypropylene, or a combination of both. The fibers may be formed into a nonwoven material by any known process contemplated by those skilled in the art including spunbonding, and needle punching. Furthermore, the nonwoven may be stitch- reinforced.

The nonwoven filler cloth may also include a binder saturation or topical binder print for additional properties such as aesthetics, hand and anti-slip performance. A binder may be any kind of synthetic or natural polymer. The binder may be applied as a water-based emulsion where the binder therein may be able to polymerize upon drying or heating of the filler cloth.

Foam materials used in mattresses or upholstered objects may include a variety of materials including thermoplastic, thermoset, natural rubber or synthetic rubber. The foam may include latex, polyurethane, or polyolefins. Furthermore, the foam may be a viscoelastic foam exhibiting shaping and relaxation memory according to applied body heat and dynamics. In other words, referring to FIG. 1, a viscoelastic foam herein may be understood to be a foam that may exhibit either a viscous (slow relative recovery) or elastic type response (fast relative recovery). In that regard, the foam may appear softer at temperatures near body temperature with the effect that the foam near the body provides improved pressure distribution when compared to a completely resilient (elastic) foam. The viscoelastic foam may therefore provide a self-contouring surface over time where the viscous response of the foam provides improved contouring to a given individual.

The foam may also be open-cell, closed-cell foam or may have special cell structures, such as elongated cells, which may exhibit specific properties such as increased firmness. The foam may have a variety of densities including 1-8 pounds per cubic foot, including all increments therebetween, including 2 to 5 pounds per cubic foot, 2.5 to 3 pounds per cubic foot, 4-5 pounds per cubic foot, or 2.0-2.5 pounds per cubic foot.

As alluded to above, the foam may also be temperature sensitive and have a decreased indentation force deflection at increased temperatures, and in particular be responsive to temperatures at or about body surface temperatures. For example, the foam may have an indentation force deflection, at 25% compression, of about 10-60 pounds at a temperature range between about 72 - 100 degrees Fahrenheit. Furthermore, the foam may have a glass transition temperature between 6 and 60 degrees Fahrenheit. Furthermore, the foam may be a multilayer or multi-sectional composite comprised of foams having varying, dimensions, cell structures, densities or firmness characteristics, such as indentation force deflection. The layers or sections may also be arranged in vertical configurations or horizontal configurations. Accordingly, in an exemplary embodiment, one layer may be viscoelastic foam and a second layer may be natural latex foam. It should be appreciated that more than 2 layers may be incorporated as well, including as many as 3 to 10 layers of foam. The foam layers may be bound together by methods known to those of ordinary skill in the art. These methods may include placing the layers together, using an adhesive layer between the sections, or lamination techniques.

The foam or foam composite or filler cloth may also contain a flame retardant or flame retardants. The flame retardant may include chemical additives to the foam or filler cloth. The invention has been described in detail with reference to specific preferred embodiments, it will be appreciated that various changes and modifications can be made, and equivalents employed, without departing from the scope of the following claims.

Claims

What is claimed is:

1. A flame retardant textile composite comprising: a filler cloth; and a flame retardant material needle punched to the filler cloth.

2. A flame retardant textile composite comprising: a viscoelastic foam; and a flame retardant material needle punched into the foam.

3. A mattress comprising: a filler cloth; and a flame retardant material needle punched into the filler cloth.

4. A mattress comprising: a foam; and a flame retardant material needle punched into the foam.