MXPA01003161A - Flame resistant fabrics - Google Patents

Abstract

The present invention provides a woven flame resistant fabric comprising dissimilar warp and fill yarns, the warp yarns comprise staple or filament fibers and have a Limiting Oxygen Index of at least 27, and the fill yarns comprise natural fibers and wherein the ratio of warp to fill yarn ends in the fabric is at least 1.0.

Description

FLAT RESISTANT FABRICS FIELD OF THE INVENTION The fabrics made of fibers resistant to flame and high temperatures have been widely used in protective suits. Despite the fact that many advances have been made in. the design of comfortable fabrics and garments made from these fibers, there are still certain aesthetic and subjective reasons for wanting flame-resistant suits, which also incorporate natural fibers. To suggest this need, the fabrics have been made from a combination of threads, which are threads containing both natural and cut fibers resistant to flame and high temperatures. Although fabrics made from such combinations of yarns can be made into comfortable garments, the resistance of fabrics at high temperatures and flame has been reduced to such an extent that the addition of flame retardants is necessary to increase the thermal protection of the fabric. Typically, flame retardants are applied to natural staple fibers or fabrics made from this combination of threads as treatments REF. : 127287 topics. The addition of topical treatments can add weight and often stiffness of the fabric as well as only provide temporary effectiveness since such treated fabrics tend to lose this protection with washing and / or cycles of use.

BACKGROUND OF THE INVENTION The object of the present invention is to provide a fabric that combines flame resistance and comfort that can be formulated in a form for the balance of thermal resolution and costs.

Another object of the present invention is to provide a comfortable, flame-resistant and cost-efficient fabric that does not require the use of topical flame retardant treatments.

Another object of the present invention is to provide a strong fabric wherein the flame resistance and cost can be balanced.

The fabrics have been made from a combination of threads to achieve certain fabric properties US Pat. Nos. 4,941,884 and 4,900,613 by Green, describe comfortable fabrics of high durability, made of warp yarns containing a mixture of at least 15% by weight of interlaced fibers of high modulus and at least 30% by weight of low modulus with full yarns containing fibers of low moduli (usually cotton). Mixed high and low modulus fibers are required in the warp yarns to provide the proper shrinkage for increased abrasion resistance.

Canadian Patent No. 1034842 discloses a protective fabric comprising interlaced weft and twist filaments of different properties with an asymmetric fabric, changing from one surface of the fabric to the opposite surface of the fabric to achieve varying energy absorbing properties through of the depth of the fabric.

European Patent Application 310,199 discloses a bullet-resistant interlaced web, made of filaments or yarns having high firmness and high modulus and consisting of polymers of ultra high molecular weights, wherein the twisted filaments or yarns consist of other different polymers of the filaments of weft or threads.

Both UK Patent Application 2,025,789 and Japanese Patent Application Publication Sho 59 (1984) -9053 disclose fabrics reinforced by the insertion or substitution at some frequency in the fabric of adjacent threads of superior firmness in the directions of the weft and / or twist. Japanese Patent Application Sho 62-26900 shows a reinforced aramidic fabric having groups of low-strength yarns inserted or replaced in the fabric of the fabric in the directions of the weft and / or twist. Such reinforced fabrics are designed for increased resistance to tearing and have not been designed with considerations for comfort or thermal protection.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a flame resistant fabric, comprising different twists and full yarns, the warp yarns comprise filament or cut fibers and have a Limiting Oxygen Index of at least 27, and full yarns. they comprise natural fibers and where the twist ratio at the ends of the filled yarn in the fabric is at least 1.0. More preferred are warp yarns that have a Limiting Oxygen Index of 28 or more.

In the present invention, the fibers of the warp yarns may have a modulus of about 100 to 800 g / dtex. Although fiber modules from 100 to about 250 g / dtex may be preferred for some uses.

It is preferred that the warp yarns comprise fibers selected from the group consisting of aramidic fibers, polybenzimidazole, polybenzoxazole, melamine, poly (phenylene sulfide), polybenzothiazoles, polyimide, polyetherimide, polyamidimides, novaloid and modacrylic, and yarn fibers. filled are selected from the group consisting of cotton, silk, wool, rayon and FR rayon. The warp yarn may be formed of fibers which are aramidic or p-aramidic fibers or mixtures of these fibers and may also incorporate about 5 wt% or less of electrically conductive fiber, particularly fibers wrapped in a carbon core.

A preferred fabric for protective suits is a fabric wherein the fibers of warp yarns are sulfonated para-aramidic fibers and the full yarn is cotton. P-aramid fibers having a modulus from 100 to not more than 200 g / dtex are particularly used in fabrics for protective suits and clothing applications.

The present invention also provides protective suits comprising a flame-resistant interlaced fabric having different full and twisted yarns, the warp yarns comprising filament or cut fibers and having a Limiting Oxygen Index of at least 27 and full yarns. they comprise natural fibers and where the ratio of twisted-to-full yarn ends in the fabric is at least 1.0.

It is preferred for the use of suits that the interlaced fabric contains warp yarn fibers selected from the group consisting of aramidic fibers, polybenzimidazole, polybenzoxazole, melamine, poly (phenylene sulfide), polybenzothiazoles, polyimide, polyetherimide, polyamidimides, novaloid and modacrylics and the filled yarn fibers are selected from the group consisting of cotton, silk, wool, rayon and RF rayon. The protective suit used can be made when the fibers of warp yarns are m-aramidic and the fibers of full yarns are RF rayon. More preferred is a protective suit wherein the warp yarns are p-aramidic fibers having a modulus of from about 100 to about 250 g / dtex. More preferred is a protective suit wherein the warp yarns are sulphonated p-aramidic fibers, and the filled fibers are cotton.

In a protective suit of claim 11, the warp yarn may further comprise about 5% by weight or less of an electrically conductive fiber. And for a protective suit, it is preferred that the warp yarns be cut fibers.

DETAILED DESCRIPTION OF THE INVENTION This invention provides flame resistant interlaced fabrics, wherein the yarns used for twisting and filling (or weft) are not similar. This fabric can be used in protective suits or for tents, awnings or other uses where a balance of rigidity of the fabric, durability of the fabric, resistance to the flame, at high temperatures and low costs are desired. In the subject fabric, the selection of warp yarn fibers provides the fabric with flame resistance and high temperatures, while the selection of full yarns provides comfort and cost efficiency. In these interwoven fabrics, the partially covered warp threads cover the filled threads. And it is believed that the warp threads thereby protect the full threads of the flame and the high temperatures. Therefore, to select the warp yarns for being only those threads that have a LOI of 27 or more, the warp threads provide thermal protection to both the full threads and the fabrics as a whole, in addition, the full threads can then be selected for having the properties that make the fabrics comfortable and cost effective. In the present invention, the warp threads are made of fabrics resistant to flame and high temperatures. Flame resistant and high temperature fabrics are those fibers that have a Limiting Oxygen Index (LOI) of at least about 27, and preferably 28 or more. Filled yarns are yarns made from natural fibers, but full yarns could be selected from natural or synthetic fibers. Special considerations may be given to the selection of warp and full yarns to provide a fabric that is suitable for a protective suit. Even with these special considerations, the fabrics of the present invention encompass a wide selection of yarns, and provide strong, comfortable and durable fabrics that suggest military and industrial standards for flame resistance and high temperatures. For fabrics suitable for protective suits, the filled yarns of this invention are selected from natural fibers. Natural fibers are those fibers found or derived from nature, including fibers such as cotton, rayon, and other fibers based on cellulose, as well as those fibers which are considered to have some natural properties of flame retardation, such like wool and silk. Rayon yarns containing a flame retardant (known as FR rayon) are particularly employed in the present invention. Nylon, polyester and other synthetic fibers which fuse on exposure to high temperatures are not suitable when used as a major component in a thread filled with a protective suit fabric. Since these fibers fuse on exposure to high temperatures, their presence can contribute to or aggravate burns. In fabrics designed for uses other than protective suits, fibers from polymers such as nylon and polyester may be acceptable for use when mixed with natural fibers. The filled yarns of the present invention may also contain electrically conductive fibers such as carbon fiber wrapped or continuous carbon fiber filaments. Such fibers reduce the possibility of sparks and other fibers having a topical antistatic treatment are much more preferred. It is recommended that such core wrapped fibers be used at a concentration of 5% by weight. The warp yarns in the present invention could have an LOI of 27 or more. The flame-resistant and high temperature fibers employed in the present invention for the manufacture of protective suit fabrics include, for example, aramidic fibers, polybenzimidazole, polybenzoxazole, melamine, poly (phenylene sulfide), polybenzothiazoles, polyimide, polyetherimide, polyamidimides, novaloide and modacrilico. These fibers decompose without the production of harmful fumes when exposed to the flame. Useful fibers include those sold under the trademarks: Kevlar (The DuPont, NOMEX (The DuPont), BASOFIL (BASF), TECHNORA (Akzo) KYNOL (Carborundum) and RYTON (Philips Chemical Company) .The warp yarns as a whole , could have an LOI of 27 or more for the fabrics of the present invention The current selection of the fibers used to make the warp yarns will be determined by the Protective Resolution Test Thermal (TPP) or other evaluation standards that - the fabric is required by convenient. For example, and ~ the current exposure conditions or temperatures and the length of the exposure (time) will influence the selection of fibers used in twisting and / or filling. In some cases, the warps may contain up to as much as 30% by weight of fibers having an LOI of less than 27, while the warp yarn as a whole has an LOI of 27 or more. The warp yarns of the present invention may also contain electrically conductive fibers such as continuous filament fibers or wrapped in synthetic carbon cores. Such fibers reduce the possibility of sparks and are much more preferred over fibers having a topical antistatic treatment. Non-permanent topical treatments comprise the resolution of the fabric of the present invention which are inherently heat and flame resistance. When the core-wrapped electrically conductive fibers are incorporated into the warp yarn, it is recommended that the concentration of these fibers be about 5% by weight or less in the warp yarn. For maximum comfort, cut yarns are preferred for warp yarns and full yarns. The high and low modulus fibers can be used in the warp yarns of the present invention, since the fiber modulus is not an essential consideration in these fabrics. Fiber warp yarns having a modulus of 100 to 800 g / dtex are suitable for use in the present invention. The lower module fibers, which are those fibers that have a modulus of less than 250 g / dtex or in the range of 100 to 200 g / dtex, are preferred for suit fabrics which are in direct contact with the wearer. way that the fabric has adequate comfort. The high module fibers may be acceptable for use on fabrics that are to be used for specific purposes or in specific locations within a garment where the comfort of the user is of less importance. Particularly employed in the fabrics of the present invention are the m and p-aramidic fibers. Such fibers include high modulus fibers such as those described in U.S. Patent No. 3,767,756 by Blades. Fibers having lower moduli include those made by the processes described in U.S. Patent No. 5,336,734 by Bowen et al., U.S. Patent No. 5,330,698, by Alien et al. & U.S. Patent No. 3,671,542 by Kwolek. Since the use of fibers having a lowermost module provide an improved comfort fabric, p-aramidics having a modulus in the range of about 100 to less than 200 g / dtex are preferred. More preferred are the sulfonated p-aramidics made in accordance with U.S. Patent No. 5,336,734. Aramidic fibers can be made from homo or co-polymers. The only requirement is that the warp threads have an LOI of 27 or more. It is desirable for the firmness and durability that the warp threads are made of fibers which are all one type of polymer resistant to flame and high temperatures. For example, the warp yarns may be 100% by weight of p-aramidics. When the maximum mechanical firmness is not important, warp threads made of mixtures of flame resistant fibers and high temperatures can be used. The use of mixed staple fibers can also provide additional comfort or help by providing additional thermal resolution. For example, a commercial mixture of 5% by weight of p-aramidic acid and 95% by weight of m-aramidic fiber threads are used for thermal resolution 3 * - "improved on 100% m-aramidic yarns. of p and m-aramidic fibers for the warp yarn is 60 wt% p-aramidic, 40 wt% m-aramidic The staple fibers made of narrow broken continuous filament fibers as well as staple fibers, can be used in the warp yarn processing of the present invention. The warp yarns themselves may be of different polymer compositions or they may be made of different cut pile folds or continuous filament fibers as long as the warp yarns suggest the LOI requirement. The selection of warp yarns or fiber blends for the warp yarns employed in the design of the fabrics of the present invention can be used to achieve a total fabric flame resistance that suggests various requirements or industrial standards. Thus, a fabric of desired comfort, durability, cost and flame resistance can be designed in accordance with the present invention for specific situations. Unless the fabric is intended for a non-wearing use, topical flame retardant or flame retardant treatments applied to the fabrics are not recommended for use in the present invention, since these fabric treatments entilate the fabric, decrease the fabric comfort to the user and tend to be temporary in nature. Again to achieve maximum mechanical firmness of the fabric, the filled yarns in accordance with the present invention are typically made from a type of natural fiber, for example, yarns filled with 100% cotton. When maximum mechanical firmness is not essential, mixtures of staple fibers can be used in full yarns, for example, full yarns containing cotton and wool. The ratio of the twisted ends per inch to full ends per inch in the fabrics of the present invention ranges from 1 to about 3, and a range of 1 to 2.5 is preferred. For clothing applications, this range relationship is essential, since the fibers in the warp yarns and the fibers in the full yarns work together not only to provide flame resistance and durability, but also comfort. In the present invention, it is preferred that all warp yarns are inherently flame resistant, which are the warp yarns containing only fibers having an LOI of 27 or more. It is preferred that the filled yarns be of natural fibers. Although there is no limitation in the LOI of full-thread fibers, full threads can, if desired, have an LOI of 27 or more. The present invention provides an effective cost-effective flame resistant fabric that can be designed for both comfort and mechanical resolution. The fabrics of this invention are employed in various protective garments, including fire suit coats, military clothing and various types of protective work pants. In addition, these fabrics can be made in shirts, pants and other suits normally placed in hazardous or industrial environments. The fabrics of this invention may also be employed in non-clothing applications, where one wishes to balance thermal protection and costs. The tents, awnings or other fabrics used to cover and protect people or property can be made from the fabrics of the present invention. The present invention is illustrated in the following example, which is not proposed to limit the invention.

EXAMPLES The flat fabric tear arrest fabrics are prepared from the following threads and interlaced in accordance with MIL-C-4436. The yarns were as follows: the yarns identified as m-aramidic are 100% poly (phenyleneisophthalamide) staple fibers; those identified as Z200 are strings cut from sulfonated p-aramidic fibers sold by E. I. DuPont Wilmington, DE as Z200; FR rayon indicates cut strings of fire retardant rayon; Mixtures of fibers in cut yarns are identified by the fibers in the mixture. These are nylon / cotton; mixtures of m-aramidic / cotton and mixtures of m-aramidic / cotton / Z200 and mixtures of Z200 / cotton.

(NOMEX is a registered trademark of E.l. DuPont). The resulting fabrics were tested for their grab (tear) firmness (ASTM-D-5034; results are reported in pounds (lbs)); trapezoidal tear firmness (ASTM-D-5733; results reported in pounds (lbs)); Elemdorf tear strength (ASTM D1474, results reported in pounds (Ibs)); abraswi_-on Tabor (ASTM-D-1044); the results are reported in cycles due to faults) and Thermal Protective Resolution, TPP (method reported in Fire Technolgy V. 13 N. 1 Feb. 1977, the results are reported in 2 times per second (2 x 2) to a burn of second grade) . The control fabric was a commercial fabric of 50% nylon, and 50% cotton yarn, in both directions of twisting and filling. This fabric was selected as the control due to its durable and comfortable fabric used for garments made for general, industrial and military garments. It is a strong, durable and comfortable fabric, but does not provide thermal protection. As shown below, the use of warp yarns in accordance with the present invention provides a fabric having surprising thermal protection properties, combined with strength and durability. The data is summarized in the Table below.

TABLE: FABRIC EVALUATION * The full thread was RF rayon with a thread of nylon tear stop filament. The total composition of the yarn filled in% by weight was filament 97 of rayon FR and 3 nylon.

In the table, the weight of the fabric is shown in oz / yd3, Firmness Grab (Grab), Trapezoidal Tear (tear trap) and Tear Elemdorf are in pounds; Tabor Abrasion (Tabor) is in cycles by faults. The term t / 11 means the result reported in the twist and then the filling direction. The compositions of full and twisted yarns are reported in% by weight of the respective yarn. Relationships are shown as% by weight as indicated. For example, 50/50 nylon / cotton means 50% by weight mixture of nylon fibers with 50% by weight of blend of cotton fibers used in the yarn processing. Ignition in air means ignition in air. The result is reported as either (Y) or not (N). If the cloth does not ignite, it means that the cloth, after being exposed to a flame for 3 to 5 seconds, does not catch fire and continues to burn. Samples A, B and C of the fabrics are fabrics of the present invention. Samples D and C are present to provide a comparison between the fabrics of the present invention and the fabrics made in accordance with the prior art methods of manufacturing thermally protective fabrics. Samples D and E are interlaced of intimately mixed cut wires. Comparing Samples C and D, one observes that both fabrics have approximately the same weight ratio of Z200 to cotton in the cloth, but the distribution of the high LOI fiber is distinctly different. In C the high LOI fiber is distributed over the surface of the fabric with the cotton in the inner full thread; while in D, different from C, the cotton is present and equally distributed on the surface of the fabric. Also, in C the warp threads are all Z200 while the full threads are all cotton. These full and twisted yarns are stronger than the intimately mixed yarns of D. For example, comparing the average of the full and twisted data the following is shown for C / D respectively, Grab 164/96; Tear Trap 31/14; and Elm. , 14/12. Observing the test results, the difference in surface flammability as measured by the ignition in the air test is very different for C compared to D.

Comparing the firmness data for C and D averaging the full and twisted values reported above, C is a stronger fabric than D. Both fabrics are approximately equal to one another in the TPP test. Fabrics A and B compared to E, show the same differences as those of the comparison of C and D, which are in each case a stronger fabric that does not catch fire in the air.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (18)

1. CLAIMS Having described the invention as above, property is claimed as contained in the following. 1. A flame-retardant, interlaced fabric, characterized in that it comprises different full and twisted yarns, the warp yarns comprise filament or cut fibers and have a Limiting Oxygen Index of at least 27, and the filled yarns comprise natural fibers and where the ratio of twisted to ends of full yarns in the fabric is at least 1.0.
2. 2. The fabric of claim 1, characterized in that the warp yarns have a Limiting Oxygen Index of 28 or more.
3. 3. The fabric of claim 1, characterized in that the fibers of the warp yarns have a modulus of about 100 to 800 g / dtex.
4. 4. The fabric of claim 1, characterized in that the fibers of the warp yarns have a modulus of from about 100 to about 250 g / dtex.
5. 5. The fabric of claim 1, characterized in that the warp yarn comprises fibers selected from the group consisting of aramidic fibers, polybenzoimidazole, polybenzoxazole, melamine, poly (phenylene sulfide), polybenzothiazoles, polyimide, polyetherimide, polyamidimides, novaolide and modacrylic, and The filled yarn fibers are selected from the group consisting of cotton, silk, wool, rayon and RF rayon.
6. 6. The fabric of claim 1, characterized in that the fibers of the warp yarns are m-aramidic or p-aramidic fibers or mixtures of these fibers.
7. characterized in that the warp yarns incorporate approximately 5% by weight or less electrically conductive fibers.
8. 8. The fabric of claim 6, characterized in that 60% by weight of the warp yarns are p-aramidic and 40% by weight are m-aramidic fibers.
9. 9. The fabric of claim 1, characterized in that the fibers of the warp yarns are sulfonated para-aramidic fibers and the filled yarns are cotton.
10. 10. The fabric of claim 1, characterized in that the fibers of the warp yarns are m-aramidic or p-aramidic fibers or mixtures of these fibers wherein the p-aramidic fibers have a modulus from 100 to not more than 200 g / dtex .
11. 11. The fabric of claim 1, characterized in that the warp yarn fibers are m-aramidic and the full yarn fibers are rayon FR.
12. 12. The protective suit characterized in that it comprises a flame-resistant interlaced fabric having different full and twisted yarns, the warp yarns comprise filament or cut fibers and have a Limiting Oxygen Index of at least 27, and the filled yarns comprise natural fibers and where the ratio of ends of twisted yarns to full yarns in the fabric is at least 1.0.
13. 13. The protective suit of claim 12, characterized in that the interlaced fabric contains warp yarn fibers selected from the group consisting of aramidic fibers, polybenzimidazole, polybenzoxazole, melamine, poly (phenylene sulfide), polybenzothiazoles, polyimide, polyetherimide, polyamideimides , novaloides and modacrilicas and the fibers of full threads are selected from the group consisting of cotton, silk, wool, rayon and RF rayon.
14. 14. The protective suit of claim 12, characterized in that the warp yarn fibers are m-aramidic and the full yarn fibers are RF rayon.
15. 15. The protective suit of claim 12, characterized in that the warp yarns are p-aramidic wherein the p-aramidic fibers have a modulus of from 100 to about 250 g / dtex.
16. 16. The protective suit of claim 12, characterized in that the warp yarn further comprises about 5% by weight or less of an electrically conductive fiber.
17. 17. The protective suit of the claim

    12, characterized in that the warp yarns are staple fibers.
18. 18. A tent or awnings, characterized in that it comprises the fabric according to claim 1.

    ,

    FABRIC RESISTANT FABRICS SUMMARY OF THE INVENTION

    The present invention provides a flame-resistant interlaced fabric, comprising different fill and twist yarns, the warp yarns comprise filament or cut fibers and have a Limiting Oxygen Index of at least 27, and the filled yarns comprise natural fibers and where the ratio of ends of full threads to

    10 twisted in the fabric is at least 1.0.

    fifteen

    twenty

    25