JP2007500802A - Flame retardant fiber mixture comprising modacrylic fiber and fabrics and garments made therefrom - Google Patents

Abstract

The intimate mixture of staple fibers comprises 10 to 75 parts by weight of at least one aramid staple fiber, 15 to 80 parts by weight of at least one modacrylic staple fiber, and 5 to 30 parts by weight of at least one polyamide staple fiber. Have. The intimate mixture of staple fibers provides yarns and fabrics that are also flame retardant and are said to be fire resistant, and can be used to produce flame retardant articles such as garments. The flame retardant fabric may have a basis weight of 0.13 to 0.50 kg / square meter (4 to 15 ounces per square yard).

Description

  There is a continuing need for fabrics that are also referred to as flame retardant, also referred to as fire resistant, that can be used to produce clothing suitable for people working near flames, high temperatures, or electric arc flashes. In addition to exhibiting excellent thermal performance, effective flame retardant fabrics should be durable, comfortable to wear and produced at low cost. Although fabrics made of inherently flame retardant fibers have so far been very useful in protective clothing, certain properties of these fibers pose problems. For example, these fibers can be difficult to dye, provide an uncomfortable fabric feel, and are expensive. To address these issues, inherently flame retardant fibers have been mixed with fibers made of other materials. Fiber blending can be used to obtain a final fabric that combines the beneficial properties of each of the component fibers. However, such blending is often done at the expense of durability and thermal performance.

  Certain fiber blends and fabrics made from the blends are known in the art. For example, U.S. Patent No. 5,099,048 (Green), issued April 24, 1990, discloses a durable heat resistant fabric comprising a mixture of cotton, nylon, and heat resistant fibers. Yes. U.S. Pat. No. 5,849,028, issued Nov. 13, 1990 (Smith, Jr.) describes a fire resistant fabric comprising a mixture of chlorine containing polymer fibers, polyacrylonitrile fibers, and fire resistant polyester binders. Disclosure. U.S. Patent No. 5,099,096 (Ichibori et al.), Issued April 2, 1996, discloses a flame retardant garment comprising natural or chemical fibers and polymer fibers containing antimony and halogen compounds. U.S. Pat. No. 5,849,017 (Lunsford et al.), Issued October 17, 2000, was dyed comprising essentially flame retardant fibers and flame retardant cellulosic fibers containing flame retardant compounds. A fabric mixture is disclosed. Patent document 5 (Zhu et al.) Issued on July 3, 2001 is a cloth made of a specific mixture of cotton, nylon, and para-aramid fibers, and is comfortable to wear and cut resistant. And a fabric that is abrasion resistant. Patent Document 6 (Shaffer et al.) Published on July 26, 2001 is a flame retardant fabric comprising different warp yarns and weft yarns, wherein the warp yarns comprise staple fibers or filament fibers. Discloses a fabric having a Limiting Oxygen Index of at least 27, wherein the weft yarn comprises natural fibers and the ratio of warp end to weft end in the fabric is at least 1.0. Patent Document 7 (Lansford et al.) Issued on April 15, 2003 discloses a method for dyeing flame retardant fabrics.

  Fabrics made from the fiber blends and yarns described above inevitably suffer from poor abrasion resistance or, as disclosed in US Pat. Most cotton fibers having low wear resistance are utilized. Fire protection garments and fire protection garments are generally used in harsh environments, so any improvement in the wear resistance of the fabrics used in these garments is important and desirable. There is therefore a need for flame retardant fiber mixtures, yarns, and fabrics with improved wear resistance.

US Pat. No. 4,920,000 U.S. Pat. No. 4,970,111 US Pat. No. 5,503,916 US Pat. No. 6,132,476 US Pat. No. 6,254,988B1 US Patent Application Publication No. 2001 / 0009832A1 US Pat. No. 6,547,835 B1

  In accordance with the purpose of the present invention as embodied and broadly described herein, the present invention provides 10 to 75 parts by weight of at least one aramid staple fiber, 15 to 80 parts by weight of at least one modacrylic. • Staple fibers and an intimate mixture of staple fibers comprising 5 to 30 parts by weight of at least one polyamide staple fiber.

  In another embodiment, the present invention provides 20-40 parts by weight of at least one aramid staple fiber, 50-80 parts by weight of at least one modacrylic staple fiber, and 15-20 parts by weight of at least one polyamide fiber. An intimate mixture of staple fibers comprising staple fibers.

  In another embodiment, the present invention relates to the above close One of the mixtures.

  The modacrylic staple fiber of the present invention preferably contains an antimony additive. A preferred antimony additive is antimony oxide.

  The intimate mixture of the present invention may be used to produce yarns, which in turn may be used to produce flame retardant fabrics for use in flame retardant articles such as clothing. .

  Further scope of the applicability of the present invention will become apparent from the detailed description provided herein below. However, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description, the detailed description and specific examples illustrate embodiments of the invention. It should be understood that this is given for illustrative purposes only. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. It is.

  For fiber blends that can produce flame retardant, also called fire resistant fabrics that can be used to produce clothes and other articles suitable for people working near fire, high temperature, or electric arc flash, etc. There is an ongoing need. Considerable efforts have been made to increase the effectiveness of such fiber blends and resulting fabrics while maintaining or improving their comfort and durability and reducing their overall cost. The present invention correctly represents such progress in the field of flame retardant garments.

  The intimate mixture of staple fibers of the present invention comprises aramid fibers, modacrylic fibers, and polyamide fibers. The proportion of each component is important to achieve the required combination of physical qualities. By “intimate mixture” is meant that two or more fiber classes are mixed prior to spinning the yarn. In the present invention, an intimate mixture is formed by combining aramid fibers, modacrylic fibers, and polyamide fibers in fiber form and then spinning into a single strand of yarn. A “yarn” is a collection of fibers spun or twisted together to form a continuous strand that is used for weaving, knitting, braiding or folding, or otherwise used to weave and knit fabrics Or a collection that can be made into cloth. Such yarns are suitable for spinning staple fibers into yarns, such as, for example, ring spinning, or higher speed pneumatic spinning techniques such as Murata Airjet spinning where air is used to twist the staples into the yarn. It can be manufactured by conventional methods.

  The intimate mixture of staple fibers of the present invention comprises aramid fibers that are inherently flame retardant. “Aramid fiber” means one or more fibers made from one or more aromatic polyamides in which at least 85% of the amide (—CONH—) bonds are directly bonded to two aromatic rings. Means. Aromatic polyamides are formed by reaction of aromatic diacid chlorides with aromatic diamines to create amide bonds in amide solvents. The aramid fibers may be spun by dry or wet spinning using any number of methods, but are not limited to U.S. Pat. Nos. 3,063,966, 3,227,793, 3 No. 3,287,324, No. 3,414,645, No. 3,869,430, No. 3,869,429, No. 3,767,756. And 5,667,743 illustrate useful spinning methods for producing fibers that can be used in the present invention.

  Aramid fibers are in two distinct classes: meta-aramid fibers made of poly (metaphenylene isophthalamide), one of which is also referred to as MPD-I, or m-aramid fibers, and one of which is also PPD-T. Para-aramid fibers made of the said poly (paraphenylene terephthalamide) or p-aramid fibers are typically available. Meta-aramid fiber is currently in several forms under the trademark NOMEX (R), EI du Pont de Nemours of Wilmington, Delaware Nomex T-450® is 100% meta-aramid, and Nomex T-455® is 95% Nomex® and 5% KEVLAR®. Nomex IIIA® (also known as Nomex T-462®) is 93% Nomex®, 5% Kevlar®, and 2 % Carbon core nylon. Furthermore, the meta-aramid fibers are trademarks CONEX (registered trademark) and APYEIL (registered trademark) produced by Teijin Limited in Tokyo, Japan and Unitika Ltd in Osaka, Japan, respectively. Trademark). Para-aramid fiber is currently available under the trademark Kevlar (R) from EI Dupont de Nemours in Wilmington, Delaware and TWARON (R) from Teijin Limited in Tokyo, Japan Is possible. For purposes herein, TECHNORA is available from Teijin Limited of Tokyo, Japan and is manufactured from copoly (p-phenylene / 3,4'-diphenyl ester terephthalamide). ) (R) fibers are considered para-aramid fibers.

  In one embodiment of the invention, the at least one aramid staple fiber is poly (metaphenylene isophthalamide).

The intimate mixture of staple fibers of the present invention also includes modacrylic fibers. Modacrylic fibers are man-made fibers that are any long-chain synthetic polymer comprising less than 85% by weight of fiber-forming material, but consisting of at least 35% by weight of acrylonitrile (—CH ₂ CH [CN] —) _x units. Modacrylic fibers are fibers made from a resin that is a copolymer (combination) of acrylonitrile and a halogen-containing compound such as vinyl chloride, vinylidene chloride or vinyl bromide. Modacrylic fibers are inherently flame retardant because they are copolymerized with these other compounds such as vinyl chloride, vinylidene chloride or vinyl bromide. Modacrylic fibers are commercially available under various trademarks, such as Protex® (ACN / polyvinylidene chloride copolymer) available from Kaneka Corporation of Osaka, Japan.

  In one embodiment of the present invention, the at least one modacrylic fiber is a copolymer of acrylonitrile and vinylidene chloride.

  The modacrylic staple fiber of the present invention preferably contains an antimony additive. A preferred antimony additive is antimony oxide, preferably added in an amount greater than 2 weight percent.

  The intimate mixture of staple fibers of the present invention also includes polyamide fibers. “Polyamide fiber” means one or more fibers made from one or more aliphatic polyamide polymers, commonly referred to as nylon. Examples include polyhexamethylene adipamide (nylon 66), polycaprolactam (nylon 6), polybutyrolactam (nylon 4), poly (9-aminononanoic acid) (nylon 9), polyenantolactam (nylon 7) , Polycapryllactam (nylon 8), and polyhexamethylene sebacamide (nylon 6,10). Nylon fibers are generally spun by extrusion of a polymer melt through a capillary into a gaseous coagulation medium. When nylon is a polyamide fiber in an intimate mixture of staple fibers that form the yarn, such yarn is warp to increase protection from soft surface wear in the finished fabric or clothing made from such fabric when the fabric is formed. Are preferably used. In one embodiment of the present invention, when nylon is thus used to produce the fabric or garment of the present invention, the fabric or garment of the present invention is measured in cycles to failure according to the following abrasion resistance test: As expected, it is expected to have at least 10 percent more abrasion resistance than a similar fabric without nylon. However, too much nylon in the fabric will cause the fabric to stiffen and lose drape when the fabric is exposed to high temperatures for short periods of time.

  In one embodiment of the present invention, the nylon fibers have a linear density of 1-3 dtex. In another embodiment, the nylon fibers have a linear density of 1-1.5 dtex. In yet another embodiment, the nylon fibers have a linear density of about 1.1 dtex.

  The intimate mixture of staple fibers of the present invention can be used to produce yarns and fabrics that are flame retardant. These yarns and fabrics can be used to produce flame retardant articles such as flame retardant clothing and garments, which are thrown in close proximity to firefighters and flames, high temperatures, or electric arc flashes It is particularly useful for other workers who In general, “flame retardant” means that the fabric does not maintain a flame in the air after a short period of contact with the flame. More precisely, “flame retardant” can be defined in terms of the vertical combustion test described below. The flame retardant fabric preferably has a carbonization length of less than 6 inches after 12 seconds exposure to flame. The terms “flame retardant”, “flame resistant”, “fireproof”, and “fire resistant” are used interchangeably in the art, and the “flame retardant” compound, fiber, yarn, fabric, and References to clothing could be described as equivalent to “flame resistance”, “fire resistance”, or “fire resistance”.

  Staple fibers for use in spinning are generally of a specific length and a specific linear density. Synthetic fiber staple lengths as long as 2.5 to 15 centimeters (1 to 6 inches) and as long as 25 centimeters (10 inches) can be used for use in the present invention. A length of ˜11.4 centimeters (1.5 to 4.5 inches) is preferred. It has been found that yarns made from such fibers having a staple length of less than 2.5 centimeters require an excessively high level of twist to maintain strength for processing. Yarns made from such fibers having a staple length greater than 15 centimeters are more difficult to manufacture due to the tendency of long staple fibers to become entangled and broken, resulting in short fibers. Synthetic staple fibers can be crimped or not crimped as desired for any particular purpose. The staple fibers of the present invention are generally produced by cutting continuous filaments to a predetermined length. However, staple fibers can be made by other methods such as stretch cutting, and yarns can be made from such fibers as well as from various or different staple fiber lengths.

  In one embodiment of the present invention, the yarns of the present invention may be used to produce a flame retardant fabric that is a cloth made by weaving, knitting or otherwise combining the yarns of the present invention. it can. Flame retardant fabrics can be constructed having warp yarns comprising the yarns of the invention, weft yarns comprising the yarns of the invention, or both warp and weft yarns comprising the yarns of the invention. If the fabric uses the yarn of the present invention in only one direction (ie, as weft yarn or warp yarn only), other suitable yarns may be used in other directions according to the desired fabric characteristics. For best wear resistance, the yarns of the present invention are used in the warp direction because warp yarns typically form most of the direct contact surface of the fabric. This will produce better wear performance on the outer surface of the fabric in the garment form.

  In one embodiment of the invention, the flame retardant fabric has a basis weight of 4 to 15 ounces per square yard. In another embodiment of the present invention, the flame retardant fabric has a basis weight of 5.5 to 11 ounces per square yard. Such fabric can be a garment such as a shirt, pants, coveralls, apron, jacket, or any other single or multi-layered form for sudden fire or electric arc protection.

  Articles of the invention will be further described below in connection with the examples. However, it should be noted that the inventive concept will not be limited in any way by these examples.

Test Methods The following test methods were used in the following examples.

Thermal insulation performance test (TPP)
The predicted protection performance of the fabric in heat and flame was measured using the “Insulation Performance Test” (National Fire Protection Association (NFPA) 2112). The flame was directed to a section of fabric mounted in a horizontal position with a defined heat flux (typically 84 kW / m ² ). The test measures the transmitted heat energy from the heat source through the specimen using a copper slag calorimeter with no space between the fabric and the heat source. The trial endpoint was estimated using the simplified model developed by Stall and Chianta, “Transactions New York Academy Science”, 33 (1971), page 649. Characterized by the time required to achieve a grade skin burn. The value assigned to the specimen in this study, denoted as “TPP value”, is the total heat energy required to achieve the endpoint, or the direct heat source exposure time to the predicted burn multiplied by the projected heat flux. A higher TPP value indicates better insulation performance.

Vertical Flammability Test The “Vertical Flammability Test” (American Society for Testing and Materials (ASTM) D6413) is a screening test to determine whether a fabric will burn or not as a predictor of whether a garment has any flame resistance Generally used. According to the test, a 3 × 12 inch section fabric was mounted vertically and a defined flame was applied to its lower edge for 12 seconds. The response of the fabric to flame exposure was recorded. The length of the burned or carbonized fabric was measured. The time for afterflame (ie, continuous burning of the fabric section after removing the test flame) and afterglow (characterized by the smoldering of the fabric section after removing the test flame) was also measured. In addition, observations regarding melting and dripping from the fabric section were also recorded. Pass / fail standards based on this method are known for industrial worker clothing, firefighter turnout equipment and fire retardant station wear, and military clothing. According to industry standards, if a fabric has a char length of less than 6 inches after 12 seconds exposure to flame, it can be considered flame retardant, or fire resistant.

Abrasion Resistance Tests Abrasion resistance is Taber available from Teledyne Taber, 455 Bryant St., North Tonawanda, NY 14120. Measured using ASTM method D3884 with H-18 wheel, 500 gm load on an abrasion meter. Taber abrasion resistance was reported as the cycle to failure.

Tear Strength Test Tear strength measurement is based on ASTM D5587. The tear strength of the knitted fabric was measured by a trapezoidal procedure using a self-recording constant speed stretch (CRE) tensile tester. Tear strength as measured by this test method requires that tearing be initiated prior to testing. The specimen was cut at the center of the smallest base of the trapezoid and started to tear. The marked non-parallel sides of the trapezoid were fixed to the parallel jaws of the tensile tester. The chin separation was continuously increased to apply force and spread the tear across the specimen. At the same time, the power to increase was recorded. The force to continue tearing was calculated from a self-recording chart recorder or a microprocessor data collection system. Two calculated values for trapezoidal tear strength were provided (single peak force and average of the five highest peak forces). For the examples here, a single peak force was used.

Grab Strength Test Grab strength measurement, which is a measure of the breaking strength and elongation of a fabric or other sheet material, is based on ASTM D5034. A 100 mm (4.0 inch) wide specimen was attached to the center of a tensile tester clamp and force was applied until the specimen broke. Values for the breaking force and elongation of the test specimen were obtained from a mechanical scale or a computer linked to the testing machine.

  Example 1 is a fabric of the present invention comprising an intimate mixture of the present invention for both warp and weft. Example 2 is a fabric of the invention comprising an intimate mixture of the present invention for warp and an intimate mixture of aramid and modacrylic for the weft. Comparative Example A is not a fabric of the present invention, but instead comprises an intimate mixture of aramid and modacrylic, without nylon, for both warp and weft. The following is a detailed description of these examples, followed by the test results for each example.

Example 1
A comfortable and durable fabric was made with warp and weft ring spinning comprising an intimate mixture of Nomex® type 462, Modacryl, and nylon. Nomex® type 462 is composed of 93% poly (m-phenylene isophthalamide) (MPD-I), 5% poly (p-phenylene terephthalamide) (PPD-T) and 2% static dissipative fibers (Wilmington, Delaware) Type P-140 available from EI DuPont de Nemours. The modacrylic fiber in this example is an ACN / polyvinylidene chloride copolymer (available under the trademark Protex (registered trademark) from Kaneka Corporation, Osaka, Japan), and the nylon used was polyhexamethylene adipamide. It was.

  A picker blend sliver of 35 weight percent Nomex® type 462, 50 weight percent modacrylic and 15 weight percent nylon is produced and typically used with a ring spinning machine to a spun yarn having a twist factor of 3.7 The cotton system was processed. The yarn so produced was a 24.6 tex (24 cotton count) single yarn. The two single yarns were then twisted on a twisting machine to produce a twin yarn for use as a warp. Using a similar method and the same twist and mixing ratio, a 32.8 tex (18 cotton count) single yarn was made and then two of these yarns were twisted together for use as a weft yarn.

Nomex® / Modacryl / nylon yarn was used as warp and weft on a loom in a 3 × 1 twill structure. The green twill fabric had a structure of 24 ends per cm × 15 picks (60 ends per inch × 39 picks) and a basis weight of 271.3 g / m ² (8 ounces / yard ² ). The raw twill fabric produced as described above was washed by scrubbing in hot water and dried under low tension. The washed fabric was then dyed with an acid dye. The finished fabric was then tested for its thermal and mechanical properties. The results of these tests are shown in Table 1.

Example 2
A ring spinning warp made from a close mixture of Nomex® type 462, modacrylic and nylon, and a ring spinning weft made from an intimate mixture of Nomex® type 462 and modacrylic. A comfortable durable fabric was produced.

  Nomex® type 462 is composed of 93% poly (m-phenylene isophthalamide) (MPD-I), 5% poly (p-phenylene terephthalamide) (PPD-T) and 2% static dissipative fibers (Wilmington, Delaware) Type P-140 available from EI DuPont de Nemours. The modacrylic in this example is an ACN / polyvinylidene chloride copolymer (available under the trademark Protex (registered trademark) from Kaneka Corporation of Osaka, Japan), and the nylon used was polyhexamethylene adipamide. It was.

  A 35% by weight Nomex® type 462, 50% by weight modacrylic and 15% by weight nylon picker blend sliver is produced and typically used with a ring spinning machine to a spun yarn having a twist factor of 3.7 The cotton system was processed. The yarn so produced was a 24.6 tex (24 cotton count) single yarn. The two single yarns were then twisted on a twisting machine to produce a twin yarn for use as a warp. Using a similar method and the same twist, a 32.8 tex (18 cotton count) single yarn of a mixture of 50 weight percent Nomex® type 462 and 50 weight percent modacrylic was produced, then these Two of the single yarns were twisted together for use as a weft yarn.

Nomex (R) / Modacryl / nylon yarn was used as warp and Nomex (R) / Modacryl yarn as weft in a 3x1 twill weave on a loom. The green twill fabric had a structure of 23 ends × 16 picks per cm (58 ends × 40 picks per inch), and a basis weight of 264.5 g / m ² (7.8 ounces / yard ² ). The raw twill fabric produced as described above was washed by scrubbing in hot water and dried under low tension. The washed fabric was then dyed with an acid dye. The finished fabric was then tested for its thermal and mechanical properties. The results of these tests are shown in Table 1.

Comparative Example A
Comfort comprising a ring spun warp made from an intimate mixture of Nomex® type 462 and modacrylic, and a ring spun weft made from an intimate mixture of Nomex® type 462 and modacrylic Made a good durable fabric.

  Nomex® type 462 is composed of 93% poly (m-phenylene isophthalamide) (MPD-I), 5% poly (p-phenylene terephthalamide) (PPD-T) and 2% static dissipative fibers (Wilmington, Delaware) Type P-140 available from EI DuPont de Nemours. The modacrylic in this example was an ACN / polyvinylidene chloride copolymer (available under the trademark Protex® from Kaneka Corporation, Osaka, Japan).

  A picker blend sliver of 50 weight percent Nomex® type 462 and 50 weight percent modacrylic is produced and processed by a conventional cotton system into a spun yarn having a twist factor of 3.7 using a ring spinning machine did. The yarn so produced was a 24.6 tex (24 cotton count) single yarn. Two of these single yarns were then twisted on a twisting machine to produce a twin yarn for use as a warp. Using a similar method and the same twist, a 32.8 tex (18 cotton count) single yarn of a mixture of 50 weight percent Nomex® type 462 and 50 weight percent modacrylic was produced, then these Two of the single yarns were twisted together for use as a weft yarn.

Nomex® / Modacrylic yarn was used as warp and weft on a loom in a 3 × 1 twill structure. The green twill fabric had a structure of 23 ends × 15 picks per cm (58 ends × 38 picks per inch), and a basis weight of 254 g / m ² (7.5 ounces / yard ² ). The raw twill fabric produced as described above was washed by scrubbing in hot water and dried under low tension. The washed fabric was then dyed with an acid dye. The finished fabric was then tested by its thermal and mechanical properties. The results of these tests are shown in Table 1.

Claims (19)

  A staple fiber comprising 10 to 75 parts by weight of at least one aramid staple fiber, 15 to 80 parts by weight of at least one modacrylic staple fiber, and 5 to 30 parts by weight of at least one polyamide staple fiber. Intimate mixture.   The intimate mixture of claim 1, wherein the at least one modacrylic staple fiber further comprises an antimony compound.   The method of claim 1, wherein there are 20-40 parts by weight of at least one aramid staple fiber, 50-80 parts by weight of at least one modacrylic staple fiber, and 15-20 parts by weight of at least one polyamide staple fiber. Intimate mixture.   The intimate mixture of claim 1, wherein the at least one aramid staple fiber is selected from the group consisting of para-aramid fibers, meta-aramid fibers, and mixtures thereof.   The intimate mixture of claim 3, wherein the at least one aramid staple fiber is selected from the group consisting of para-aramid fibers, meta-aramid fibers, and mixtures thereof.   The intimate mixture of claim 1 wherein at least one aramid staple fiber is poly (methphenyleneisophthalamide) and at least one modacrylic fiber is a copolymer of acrylonitrile and vinylidene chloride.   The intimate mixture of claim 3, wherein the at least one aramid staple fiber is poly (metaphenylene isophthalamide) and the at least one modacrylic fiber is a copolymer of acrylonitrile and vinylidene chloride.   A yarn comprising the intimate mixture of claim 1.   A flame-retardant cloth comprising the yarn according to claim 8.   The flame retardant fabric of claim 9, wherein the flame retardant fabric has a basis weight of 4 to 15 ounces per square yard.   A flame-retardant garment comprising the flame-retardant cloth according to claim 10.   The flame retardant fabric of claim 9, wherein the flame retardant fabric has a basis weight of 5.5 to 11 ounces per square yard.   A flame-retardant garment comprising the flame-retardant cloth according to claim 12.   A yarn comprising the intimate mixture of claim 6.   A flame retardant fabric comprising the yarn according to claim 14.   The flame retardant fabric of claim 15, wherein the flame retardant fabric has a basis weight of 4 to 15 ounces per square yard.   A flame-retardant garment comprising the flame-retardant cloth according to claim 16.   The flame retardant fabric of claim 15, wherein the flame retardant fabric has a basis weight of 5.5 to 11 ounces per square yard. A flame-retardant garment comprising the flame-retardant cloth according to claim 18.