US20060183393A1

US20060183393A1 - Drapeable and launderable light weight flame retardant barrier fabrics

Info

Publication number: US20060183393A1
Application number: US11/353,925
Authority: US
Inventors: Samuel Gillette
Original assignee: Precision Fabrics Group Inc
Current assignee: Precision Fabrics Group Inc; Microsoft Corp
Priority date: 2005-02-14
Filing date: 2006-02-13
Publication date: 2006-08-17

Abstract

Flame retardant (FR) nonwoven fabrics and methods of producing same are provided. An FR nonwoven fabric includes FR rayon and either FR polyester or FR polypropylene or any blend thereof. The FR nonwoven fabric has a basis weight less than 3 ounces per square yard, and is devoid of non-FR binder material. The FR nonwoven fabric displays substantial flame retardant properties after five home launderings in accordance with protocols set forth in AATCC Test Method 135-1995. The FR nonwoven fabric is configured to maintain flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in Technical Bulletin 604 of the State of California Department of Consumer Affairs (TB-604), and to maintain flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in National Fire Protection Agency 701-1989 test method.

Description

RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Patent Application No. 60/652,582 filed Feb. 14, 2005, the disclosure of which is incorporated herein by reference as if set forth in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to fabrics and, more particularly, to flame retardant fabrics.

BACKGROUND OF THE INVENTION

There is heightened awareness of fire prevention in homes and businesses in the United States. This awareness has led to the development of standards and legislation directed to reducing the risk of fires, particularly with respect to bedding and upholstered furniture. Conventional fire prevention techniques for bedding and upholstered furniture involve the topical application of flame retardant (FR) chemicals directly to an outer decorative layer of upholstery material.
California Technical Bulletin 603 of the State of California Department of Consumer Affairs (hereinafter “TB-603”), which is incorporated herein by reference in its entirety, exposes the top and side panels of a mattress to an open gas flame to simulate the effects of burning bedclothes. TB-603 is extremely aggressive relative to conventional cigarette burn tests and many industry analysts are skeptical that conventional fabrics used to upholster furniture and bedding products (e.g., mattresses, etc.) will be able to pass TB-603.
Because of TB-603, the furniture and bedding industries have been forced to utilize FR barrier fabrics capable of passing TB-603, e.g., treated or coated fabrics, and fabrics comprised of inherently FR fibers. Barrier fabrics capable of satisfying TB-603 can be lofty, can require the use of binder fibers, and/or can have a high basis weight.
California Technical Bulletin 604 of the State of California Department of Consumer Affairs (hereinafter “TB-604”), which is incorporated herein by reference in its entirety, uses a small flame, such as that representative of a pillow case burning, to challenge a barrier fabric positioned between the flame and a fiber/foam filling. The advent of TB-604 has generated a need for a new type of barrier fabric—one that is launderable and more drapeable than current FR barrier fabrics. This need arises because pillows and comforters generally experience between five and ten home launderings (which can wash off the FR chemicals) in their life time and because consumers prefer soft pillows and comforters. Furthermore, a fabric which can act as a TB-604 FR barrier fabric in a pillow or comforter need not be thick and insulative because these materials will not experience the tremendous heat flux of a TB-603 flame.
FR rayon, when incorporated into a fabric, contributes to the formation of a barrier-forming char when the fabric is exposed to flame. However, binder fibers (e.g., latex binder fibers) are conventionally required to hold FR rayon into a nonwoven structure. See, for example, U.S. Patent Application Publication No. 2004/0102112, which describes a fabric held together by between 6% and 25% of non-FR low melt binder fiber or latex resin. Unfortunately, because they are combustible, binder fibers are deleterious to the flame retardant performance of the fabric.
Therefore, rayon is conventionally treated by topically applying (e.g., spraying or padding) chemicals thereon that react with the rayon. Unfortunately, topical FR treatment of rayon/polyester blended nonwoven fabrics or rayon/polypropylene blended fabrics have been hampered because FR treatments that work on rayon may not work on polypropylene or on polyester. Similarly, FR treatments that work on polypropylene or on polyester may not work on rayon. Thus, in order to effectively treat a rayon/polyester or a rayon/polypropylene blended fabric with FR chemicals, it is necessary to finish the fabric twice or to treat both the rayon and the polyester or polypropylene in a single bath. However, this process results in the chemicals intended to treat the rayon washing off of the polyester and polypropylene during laundering and the chemicals intended for the polypropylene and polyester washing off of the rayon during laundering. Thus there is a tremendous inherent waste of chemicals and resultant pollution when nonwoven rayon/polyester fabrics or nonwoven rayon/polypropylene fabrics are topically treated with FR chemicals.
In addition, it is hard to crosslink FR chemicals to cellulose fibers within a fabric containing rayon. In order to form a covalent bond with cellulose, formaldehyde releasing agents (or other crosslinking agents such as aziridine, epoxy or urethane containing products) are often employed. Alternatively, an acid or base catalyst can be utilized to force etherification or esterification of cellulose; however, these catalysts must be subsequently rinsed out so as not to cause yellowing or tenderizing of a fabric, and to prevent the fabric from causing allergic reactions in users of the fabric.
U.S. Patent Application Publication No. 2004/0097156 describes a fabric of at least 5 ounces per square yard which is composed of a blend of FR rayon, FR acrylic and FR melamine fibers. U.S. Patent Application Publication No. 2004/0097156 describes a structure similar to U.S. Patent Application Publication No. 2004/0102112 but with the added requirement that the basis weight be over 5 ounces per square yard.

SUMMARY OF THE INVENTION

In view of the above discussion, flame retardant (FR) nonwoven fabrics and methods of producing same are provided. According to some embodiments of the present invention, an FR nonwoven fabric includes FR rayon and either FR polyester or FR polypropylene or any blend thereof. The FR nonwoven fabric has a basis weight of less than 3 ounces per square yard, and is completely devoid of non-FR binder material. The FR nonwoven fabric displays substantial flame retardant properties after five home launderings in accordance with protocols set forth in AATCC Test Method 135-1995. In addition, the FR nonwoven fabric is configured to maintain flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in Technical Bulletin 604 of the State of California Department of Consumer Affairs (TB-604), and to maintain flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in National Fire Protection Agency 701-1989 test method.
According to some embodiments of the present invention, an FR nonwoven fabric includes between about 10% and 90% FR rayon and between about 10% and 90% FR polyester. According to some embodiments of the present invention, an FR nonwoven fabric includes between about 10% and 90% FR rayon and between about 10% and 90% FR polypropylene.
According to some embodiments of the present invention, a method of producing FR nonwoven fabric includes blending FR polypropylene fibers and FR rayon fibers, forming a web of the blended polypropylene and rayon fibers, heating the web to a temperature sufficient to cause adjacent polypropylene fibers to bond together, and calendaring the heated web. The FR polypropylene fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. The rayon fibers comprise between about 10% and 90% of the blend and the polypropylene fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend).
According to some embodiments of the present invention, a method of producing FR nonwoven fabric includes blending FR polyester fibers and FR rayon fibers, forming a web of the blended polyester and rayon fibers, heating the web to a temperature sufficient to cause adjacent polyester fibers to bond together, and calendaring the heated web. The FR polyester fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. The rayon fibers comprise between about 10% and 90% of the blend and the polyester fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend).
According to some embodiments of the present invention, a method of producing FR nonwoven fabric includes blending FR polypropylene fibers and FR rayon fibers, forming a first web of the blended polypropylene and rayon fibers, wherein the fibers are oriented in a machine direction, forming a second web of the blended polypropylene and rayon fibers, wherein the fibers are oriented in a cross direction, and bonding the first and second webs together. The FR polypropylene fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. The rayon fibers comprise between about 10% and 90% of the blend and the polypropylene fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend). The first and second webs are bonded together in any of various ways including, but not limited to, thermal bonding, stitch bonding, hydroentangling or spunlacing, and needlepunching.
According to some embodiments of the present invention, a method of producing FR nonwoven fabric includes blending FR polyester fibers and FR rayon fibers, forming a first web of the blended polyester and rayon fibers, wherein the fibers are oriented in a machine direction, forming a second web of the blended polyester and rayon fibers, wherein the fibers are oriented in a cross direction, and bonding the first and second webs together. The FR polyester fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. The rayon fibers comprise between about 10% and 90% of the blend and, the polyester fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend). The first and second webs are bonded together in any of various ways including, but not limited to, thermal bonding, stitch bonding, hydroentangling or spunlacing, and needlepunching.
FR nonwoven fabric, according to embodiments of the present invention, has a low basis weight, is drapeable, is environmentally friendly and is launderable. Moreover, FR nonwoven fabric, according to embodiments of the present invention, does not include any combustible components such as binder fibers and latex binders. FR nonwoven fabric, according to embodiments of the present invention, requires no further need for treatment in order to comply with TB-603 and TB-604.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 are flow charts of methods of producing FR nonwoven fabric, according to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
As used herein, phrases such as “between X and Y” and “between about X and Y” should be interpreted to include X and Y. As used herein, phrases such as “between about X and Y” mean “between about X and about Y.” As used herein, phrases such as “from about X to Y” mean “from about X to about Y.”
As used herein, the term “flame resistant material” means a material that passes the requirements of National Fire Protection Association (NFPA) 701-1989.
As used herein, the term “drapeable” means non-self supporting or non-stiff. That is, a drapeable fabric when placed on top of an object will drape down upon the object.
According to embodiments of the present invention, a drapeable FR nonwoven fabric includes a blend of FR rayon fibers and FR polyester fibers, or a blend of FR rayon fibers and FR polypropylene fibers and has a basis weight less than 3 ounces per square yard. For example, the FR nonwoven fabric may include between about 10% and 90% FR rayon fibers and between about 10% and 90% FR polyester fibers. Alternatively, the FR nonwoven fabric may include between about 10% and 90% FR rayon fibers and between about 10% and 90% FR polypropylene fibers. Moreover, FR nonwoven fabric, according to embodiments of the present invention, is devoid of combustible material such as, for example, latex binder material, non-FR binder fibers, etc. Exemplary FR rayon fibers are available from Lenzing AG, Austria; exemplary FR polyester fibers are available from Far Eastern Textile, Ltd., Taipei, Taiwan; and exemplary FR polypropylene fibers are available from FiberVisions, Covington, Ga.
FR nonwoven fabric, according to embodiments of the present invention, is configured to display substantial flame retardant properties after five home launderings in accordance with protocols set forth in AATCC (American Association of Textile Chemists and Colorists) Test Method 135-1995 (e.g., machine cycle=delicate, wash temperature=27±3° C., line dry). In addition, FR nonwoven fabric, according to embodiments of the present invention, is configured to maintain flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in Technical Bulletin 604 of the State of California Department of Consumer Affairs (TB-604), and when impinged with a gas flame in accordance with testing protocols set forth in National Fire Protection Agency 701-1989 test method.
According to embodiments of the present invention, nonwoven fabric, such as thermal bond nonwoven fabric, spunlaced nonwoven fabric, stitch bonded nonwoven fabric, or needlepunched nonwoven fabric, is provided that is comprised entirely of either a blend of FR rayon and FR polyester or of a blend or FR rayon and FR polypropylene. Applicants have discovered how to select and control the following parameters such that rayon/polyester and rayon/polypropylene blended FR fabrics can achieve desired end use properties such as wash durability, flame retardancy, char formation and soft drapeable hand and without the inherent problems of conventional FR fabrics: fiber denier, fiber length, opening process, blending process, carding process and consolidation (spunlace, stitch bond and needlepunch), bonding (thermal bond) parameters. In addition, rayon/polyester and rayon/polypropylene blended FR fabrics, according to embodiments of the present invention, may utilize prodegradants, crimped fibers, fibers with amorphous and crystalline zones, bicomponent fibers, sheath core fibers, fibers with high or low modulus, short or long fibers, low or high denier fibers, mixtures of different types of fibers, fiber treatments, fibers with differential melting rates and differential melting points, etc.
Referring to FIG. 1, a method of producing FR nonwoven fabric, according to some embodiments of the present invention, includes blending FR polypropylene fibers and FR rayon fibers (Block 100), forming a web of the blended polypropylene and rayon fibers (Block 110), heating the web to a temperature sufficient to cause adjacent polypropylene fibers to bond together (Block 120), and calendaring the heated web (Block 130). According to some embodiments of the present invention, the FR polypropylene fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. According to some embodiments of the present invention, the rayon fibers comprise between about 10% and 90% of the blend and the polypropylene fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend). According to some embodiments of the present invention, calendaring the heated web (Block 130) may be performed via various types of calendar rolls such as, for example, patterned calendar rolls.
Referring to FIG. 2, a method of producing FR nonwoven fabric, according to some embodiments of the present invention, includes blending FR polyester fibers and FR rayon fibers (Block 200), forming a web of the blended polyester and rayon fibers (Block 210), heating the web to a temperature sufficient to cause adjacent polyester fibers to bond together (Block 220), and calendaring the heated web (Block 230). According to some embodiments of the present invention, the FR polyester fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers.
According to some embodiments of the present invention, the rayon fibers comprise between about 10% and 90% of the blend and the polyester fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend). According to some embodiments of the present invention, calendaring the heated web (Block 230) may be performed via various types of calendar rolls such as, for example, patterned calendar rolls.
Referring to FIG. 3, a method of producing FR nonwoven fabric, according to some embodiments of the present invention, includes blending FR polypropylene fibers and FR rayon fibers (Block 300), forming a first web of the blended polypropylene and rayon fibers, wherein the fibers are oriented in a machine direction (Block 310), forming a second web of the blended polypropylene and rayon fibers, wherein the fibers are oriented in a cross direction (Block 320), and bonding the first and second webs together (Block 330).
According to some embodiments of the present invention, the FR polypropylene fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. According to some embodiments of the present invention, the rayon fibers comprise between about 10% and 90% of the blend and the polypropylene fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend).
The fibers in the first web are oriented along the machine direction of the first web, i.e., along the lengthwise direction of the first web. The fibers in the second web are oriented along the cross direction of the second web, i.e., along the widthwise direction of the second web. The first and second webs are bonded together (Block 330) in any of various ways including, but not limited to, thermal bonding, stitch bonding, hydroentangling or spunlacing, and needlepunching. Spunlacing, stitch bonding, needle punching, and thermal bonding are well understood by those skilled in the art and need not be described herein.
Referring to FIG. 4, a method of producing FR nonwoven fabric, according to some embodiments of the present invention, includes blending FR polyester fibers and FR rayon fibers (Block 400), forming a first web of the blended polyester and rayon fibers, wherein the fibers are oriented in a machine direction (Block 410), forming a second web of the blended polyester and rayon fibers, wherein the fibers are oriented in a cross direction (Block 420), and bonding the first and second webs together (Block 430).
According to some embodiments of the present invention, the FR polyester fibers are 2 denier, 2 inch fibers and the FR rayon fibers are 1.5 denier, 2 inch fibers. According to some embodiments of the present invention, the rayon fibers comprise between about 10% and 90% of the blend and the polyester fibers comprise the remaining percentage (i.e., between about 10% and 90% of the blend).
The fibers in the first web are oriented along the machine direction of the first web, i.e., along the lengthwise direction of the first web. The fibers in the second web are oriented along the cross direction of the second web, i.e., along the widthwise direction of the second web. The first and second webs are bonded together (Block 430) in any of various ways including, but not limited to, thermal bonding, stitch bonding, hydroentangling or spunlacing, and needlepunching.
The following examples are not intended to limit the scope of the present invention, but are set forth as examples of embodiments of the present invention.

EXAMPLES

Example 1

Thermal Bond Nonwoven Fabric Production
2 denier, 2 inch FR polypropylene fibers are weighed into fiber blending equipment and mixed with a desired amount of 1.5 denier, 2 inch FR rayon fibers to accomplish thorough mixing of the fiber blend. The resulting blend is conveyed using an air conveyer system to opening equipment which further separates the fibers and lays them down in thick batt or web. Then the web is conveyed on a belt to a carding machine that uses counter rotating teeth or wires to further refine and compress the web. The web is then conveyed on a belt to a forced air or infrared oven or to a through air heating dryer. The supported web is rapidly raised to a high enough temperature to melt the outer sheath of the polypropylene fiber in order to cause it to bond with adjacent polypropylene fibers and to some extent with the FR rayon fibers. The web is then conveyed out of the oven or heating chamber and may either be calendared using a patterned calendar roll or cooled and rolled up. Between 10% and 90% of FR polypropylene is recommended for use in the thermal bonding process described above with the remainder of the fiber being FR rayon in order to produce a strong enough flame resistant barrier to meet the end use requirements of TB-604 barrier products. The above experiment may also be performed by substituting FR polyester for the FR polypropylene.

Example 2

Stitch Bond Nonwoven Fabric Production
2 denier, 2 inch FR polypropylene fibers are weighed into fiber blending equipment and mixed with a desired amount of 1.5 denier, 2 inch FR rayon fibers to accomplish thorough mixing of the fiber blend. The resulting blend is conveyed using an air conveyer system to opening equipment which further separates the fibers and lays them down in thick batt or web. Then the web is conveyed on a belt to a carding machine that uses counter rotating teeth or wires to further refine and compress the web. In order to achieve a more uniform ratio of machine direction (MD) to cross direction (XD) oriented fibers in the nonwoven fabric, it may be desirable to produce two carded fiber batts one of which is oriented in the machine direction relative to the spunlacing equipment with the other being cross lapped over the first web. Other processes may also be used to form the unconsolidated web including drafting, consolidating or stretching the fiber batt. Next the fiber batt is passed through a process in which filament yarn on a warp beam is threaded through needles that stitch or knit through the fiber batt. The stitching or knitting process consolidates the fibers in the fiber batt and binds the fibers together to form a strong composite fabric. This process is known as stitch bonding, as would be understood by those skilled in the art.

Example 3

Spunlaced Nonwoven Fabric Production
2 denier, 2 inch FR polypropylene fibers are weighed into fiber blending equipment and mixed with a desired amount of 1.5 denier, 2 inch FR rayon fibers to accomplish thorough mixing of the fiber blend. The resulting blend is conveyed using an air conveyer system to opening equipment which further separates the fibers and lays them down in thick batt or web. Then the web is conveyed on a belt to a carding machine that uses counter rotating teeth or wires to further refine and compress the web. In order to achieve a more uniform ratio of MD to XD oriented fibers in the nonwoven fabric, it may be desirable to produce two carded fiber batts one of which is oriented in the machine direction relative to the spunlacing equipment with the other being cross lapped over the first web. Other processes may also be used to form the unconsolidated web including drafting, consolidating or stretching the fiber batt. Next the fiber batt is passed under high pressure water jets which are used to consolidate and hydroentangle the fibers in the web in a process which is well known to those familiar with the art of spunlacing.

Example 4

Needlepunched Nonwoven Fabric Production
2 denier, 2 inch FR polypropylene fibers are weighed into fiber blending equipment and mixed with a desired amount of 1.5 denier, 2 inch FR rayon fibers to accomplish thorough mixing of the fiber blend. The resulting blend is conveyed using an air conveyer system to opening equipment which further separates the fibers and lays them down in thick batt or web. Then the web is conveyed on a belt to a carding machine that uses counter rotating teeth or wires to further refine and compress the web. In order to achieve a more uniform ratio of MD to XD oriented fibers in the nonwoven fabric, it may be desirable to produce two carded fiber batts one of which is oriented in the machine direction relative to the spunlacing equipment with the other being cross lapped over the first web. Other processes may also be used to form the unconsolidated web including drafting, consolidating or stretching the fiber batt. Next the fiber batt is passed under bank of reciprocating needles that are designed to consolidate and entangle the fibers in the web in a process which is well known to those familiar with the art of needlepunching.

Claims

1. A flame retardant (FR) nonwoven fabric, comprising between about 10% and 90% FR rayon and between about 10% and 90% FR polyester, wherein the FR nonwoven fabric has a basis weight less than 3 ounces per square yard, and wherein the FR nonwoven fabric is devoid of non-FR binder material.

2. The FR nonwoven fabric of claim 1, wherein the FR nonwoven fabric is manufactured using a process selected from the group consisting of hydroentangling, stitch bonding, needle punching, and thermal bonding.

3. The FR nonwoven fabric of claim 1, wherein the FR nonwoven fabric displays substantial flame retardant properties after five home launderings in accordance with protocols set forth in AATCC Test Method 135-1995.

4. The FR nonwoven fabric of claim 1, wherein the FR nonwoven fabric maintains flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in Technical Bulletin 604 of the State of California Department of Consumer Affairs (TB-604).

5. The FR nonwoven fabric of claim 1, wherein the FR nonwoven fabric maintains flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in National Fire Protection Agency 701-1989 test method.

6. A flame retardant (FR) nonwoven fabric, comprising between about 10% and 90% FR rayon and between about 10% and 90% FR polypropylene, wherein the FR nonwoven fabric has a basis weight less than 3 ounces per square yard, and wherein the FR nonwoven fabric is devoid of non-FR binder material.

7. The FR nonwoven fabric of claim 6, wherein the FR nonwoven fabric is manufactured using a process selected from the group consisting of hydroentangling, stitch bonding, needle punching, and thermal bonding.

8. The FR nonwoven fabric of claim 6, wherein the FR nonwoven fabric displays substantial flame retardant properties after five home launderings in accordance with protocols set forth in AATCC Test Method 135-1995.

9. The FR nonwoven fabric of claim 6, wherein the FR nonwoven fabric maintains flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in Technical Bulletin 604 of the State of California Department of Consumer Affairs (TB-604).

10. The FR nonwoven fabric of claim 6, wherein the FR nonwoven fabric maintains flame and heat resistant integrity when impinged with a gas flame in accordance with testing protocols set forth in National Fire Protection Agency 701-1989 test method.

11. A method of producing flame retardant (FR) nonwoven fabric, comprising:

blending FR polypropylene fibers and FR rayon fibers;

forming a web of the blended polypropylene and rayon fibers, wherein the web has a basis weight less than 3 ounces per square yard; and

heating the web to a temperature sufficient to cause adjacent polypropylene fibers to bond together.

12. The method of claim 11, further comprising calendaring the heated web via a patterned calendar roll.

13. The method of claim 11, wherein the FR polypropylene fibers are 2 denier, 2 inch fibers and wherein the FR rayon fibers are 1.5 denier, 2 inch fibers.

14. The method of claim 11, wherein blending FR polypropylene fibers and FR rayon fibers comprises blending between about 10% and 90% FR rayon fibers and between about 10% and 90% FR polypropylene fibers.

15. A method of producing flame retardant (FR) nonwoven fabric, comprising:

blending FR polyester fibers and FR rayon fibers;

forming a web of the blended polyester and rayon fibers, wherein the web has a basis weight less than 3 ounces per square yard; and

heating the web to a temperature sufficient to cause adjacent polyester fibers to bond together.

16. The method of claim 15, further comprising calendaring the heated web via a patterned calendar roll.

17. The method of claim 15, wherein the FR polyester fibers are 2 denier, 2 inch fibers and wherein the FR rayon fibers are 1.5 denier, 2 inch fibers.

18. The method of claim 15, wherein blending FR polyester fibers and FR rayon fibers comprises blending between about 10% and 90% FR rayon fibers and between about 10% and 90% FR polyester fibers.

19. A method of producing flame retardant (FR) nonwoven fabric, comprising:

blending FR polypropylene fibers and FR rayon fibers;

forming a first web of the blended polypropylene and rayon fibers, wherein the fibers are oriented in a machine direction;

forming a second web of the blended polypropylene and rayon fibers, wherein the fibers are oriented in a cross direction; and

bonding the first and second webs together to form a composite web having a basis weight less than 3 ounces per square yard.

20. The method of claim 19, wherein the FR polypropylene fibers are 2 denier, 2 inch fibers and wherein the FR rayon fibers are 1.5 denier, 2 inch fibers.

21. The method of claim 19, wherein bonding the first and second webs together comprises stitch bonding the first and second webs.

22. The method of claim 19, wherein bonding the first and second webs together comprises spunlacing the first and second webs.

23. The method of claim 19, wherein bonding the first and second webs together comprises needlepunching the first and second webs.

24. A method of producing flame retardant (FR) nonwoven fabric, comprising:

blending FR polyester fibers and FR rayon fibers;

forming a first web of the blended polyester and rayon fibers, wherein the fibers are oriented in a machine direction;

forming a second web of the blended polyester and rayon fibers, wherein the fibers are oriented in a cross direction; and

25. The method of claim 24, wherein the FR polyester fibers are 2 denier, 2 inch fibers and wherein the FR rayon fibers are 1.5 denier, 2 inch fibers.

26. The method of claim 24, wherein bonding the first and second webs together comprises stitch bonding the first and second webs.

27. The method of claim 24, wherein bonding the first and second webs together comprises spunlacing the first and second webs.

28. The method of claim 24, wherein bonding the first and second webs together comprises needlepunching the first and second webs.