Mixed yarn and woven or knitted fabric including the same and fire retardant clothing

Abstract

To provide a mixed yarn achieving excellent heat resistance and feeling.SOLUTION: The mixed yarn includes fire-retardant fibers having a limiting oxygen index or 25 or more, and para-aramid fibers. The content of the para-amid fibers is 35 to 65 wt.%. For example, the content of the fire-retardant fibers in the mixed yarn may be 35 to 65 wt.%. The fire-retardant fibers in the mixed yarn may be fire retardant fibers to be carbonized.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a blended yarn, a woven or knitted fabric comprising the blended yarn, and a flame-retardant garment comprising the woven or knitted fabric. [Background technology]

[0002] Flame-retardant clothing is used as work clothes, firefighting uniforms, etc. worn at various work sites and fire scenes. Traditionally, aramid fibers have been used in flame-retardant clothing. For example, Patent Document 1 (JP 2008-101294 A) discloses a flame-retardant woven fabric made of spun yarn containing heat-resistant fibers and carbonizable flame-retardant fibers in a weight ratio of 65:35 to 35:65, and describes that the fabric is breathable and lightweight. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-101294 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the spun yarn in the examples of Patent Document 1 uses meta-aramid fiber, para-aramid fiber, or the like as a heat-resistant fiber, the weight ratio of the para-aramid fiber is low, and therefore such a spun yarn has poor heat resistance and there is room for improvement for use as a constituent fiber of flame-retardant clothing that is exposed to high temperatures.

[0005] Para-aramid fibers have a rigid molecular structure that makes them resistant to deformation and heat resistance, but they are prone to fibrillation, so spun yarns containing a high weight ratio of para-aramid fibers have a poor texture.

[0006] Therefore, an object of the present invention is to provide a blended yarn that has both heat resistance and texture. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have found that a blended yarn containing a specific content of para-aramid fiber and a flame-retardant fiber has excellent heat resistance and excellent texture, and have completed the present invention.

[0008] That is, the present invention can be configured in the following manner. [Aspect 1] A blended yarn containing a flame-retardant fiber having a limiting oxygen index of 25 or more and a para-aramid fiber, wherein the content of the para-aramid fiber is 35 to 65% by weight (preferably 40 to 60% by weight, more preferably 45 to 55% by weight, and even more preferably 48 to 52% by weight). [Aspect 2] The blended yarn according to aspect 1, wherein the content of the flame-retardant fiber is 35 to 65% by weight (preferably 40 to 60% by weight, more preferably 45 to 55% by weight, and even more preferably 48 to 52% by weight). Aspect 3 3. The blended yarn of claim 1 or 2, wherein the flame-retardant fiber is a carbonizing flame-retardant fiber (preferably a flame-retardant polyvinyl alcohol fiber). Aspect 4 A woven or knitted fabric comprising the blended yarn according to any one of aspects 1 to 3. Aspect 5 A flame-retardant garment comprising the woven or knitted fabric according to embodiment 4. [Effects of the Invention]

[0009] The blended yarn of the present invention can achieve both heat resistance and texture. Woven and knitted fabrics containing the blended yarn of the present invention can be suitably used for flame-retardant clothing. DETAILED DESCRIPTION OF THE INVENTION

[0010] The blended yarn contains a flame-retardant fiber having a limiting oxygen index of 25 or more and a para-aramid fiber, and the content of the para-aramid fiber is 35 to 65% by weight. In the blended yarn containing the flame-retardant fiber and the para-aramid fiber, the specific content of the para-aramid fiber provides excellent heat resistance and texture. The blended yarn is a spun yarn made by mixing and spinning multiple types of staple fibers.

[0011] If the content of para-aramid fiber is less than 35% by weight, heat resistance will be poor, resulting in gaps between flame-retardant clothing, etc., which may allow flames or radiant heat to enter through the gaps. On the other hand, if the content of para-aramid fiber exceeds 65% by weight, heat resistance can be improved, but the texture will be poor, which may reduce comfort when wearing the flame-retardant clothing. The content of para-aramid fiber in the blended yarn may be preferably 40 to 60% by weight, more preferably 45 to 55% by weight, and even more preferably 48 to 52% by weight.

[0012] Para-aramid fibers are fibers made of polyamides containing structural units derived from aromatic diamines, aromatic dicarboxylic acids, aromatic aminocarboxylic acids, etc. Examples of such polyamides include polyparaphenylene terephthalamide containing structural units derived from paraphenylenediamine and structural units derived from terephthalic acid; copolyparaphenylene-3,4'-oxydiphenylene terephthalamide containing structural units derived from paraphenylenediamine and structural units derived from 3,4'-diaminodiphenyl ether as aromatic diamines, and structural units derived from terephthalic acid as aromatic dicarboxylic acid; and derivatives thereof.

[0013] The flame-retardant fiber has a limiting oxygen index of 25 or more and is a fiber different from para-aramid fiber. In addition to the heat resistance of para-aramid fiber, the blended yarn has excellent flame retardancy due to the inclusion of the flame-retardant fiber, and therefore can be used as a constituent fiber for flame-retardant clothing. The limiting oxygen index (LOI) is a value measured by the method described in the Examples below.

[0014] Flame-retardant fibers are not particularly limited as long as they have a limiting oxygen index of 25 or higher. Examples include flame-retardant fibers such as flame-retardant polyvinyl alcohol fibers, flame-retardant acrylic fibers, oxidized acrylic fibers, flame-retardant polyester fibers, and flame-retardant rayon; halogen-containing fibers such as polyvinyl chloride fibers, polyvinylidene chloride fibers, polychlor fibers, and polytetrafluoroethylene fibers; and heat-resistant fibers such as meta-aramid fibers, polyarylate fibers, polyphenylene sulfide fibers, polyimide fibers, polyetherimide fibers, polyamideimide fibers, polyetheretherketone fibers, polyparaphenylenebenzobisoxazole fibers, polyparaphenylenebenzobisimidazole fibers, polyparaphenylenebenzobisthiazole fibers, and phenol fibers. The resins constituting these fibers include derivatives of various resins, which may be modified, for example, by copolymerization or chemical modification. These flame-retardant fibers may be used alone or in combination.

[0015] From the viewpoint of improving the flame retardancy of the blended yarn, the flame-retardant fiber is preferably a carbonizing flame-retardant fiber. When exposed to flame, the resin constituting the fiber heats and carbonizes its surface, forming a carbonized layer that blocks oxygen and exhibits flame retardancy. Due to this mechanism of flame retardancy, the carbonizing flame-retardant fiber can coat the mesh of woven or knitted fabrics containing the blended yarn with a carbonized layer, thereby inhibiting the passage of flame and allowing the woven or knitted fabric to exhibit flame retardancy. Examples of carbonizing flame-retardant fibers include fibers made of resins in which a flame retardant capable of forming a carbonized layer, such as a phosphorus-based flame retardant, is dispersed in the resin, or in which a flame-retardant functional group, such as a phosphorus-based functional group, is introduced into the molecule by copolymerization or chemical modification, and fibers in which a halogen compound, such as chlorine, bromine, or fluorine, is copolymerized into the fiber polymer. Examples of such fibers include the flame-retardant fibers and halogen-containing fibers described above. Among these, flame-retardant polyvinyl alcohol fibers are preferred from the viewpoint of further improving the texture by blending with para-aramid fibers and from the viewpoint of excellent dyeability in post-processing.

[0016] From the viewpoint of ensuring flame retardancy and further improving heat resistance and texture, the content of the flame-retardant fiber in the blended yarn may be 35 to 65% by weight, preferably 40 to 60% by weight, more preferably 45 to 55% by weight, and even more preferably 48 to 52% by weight. When two or more types of flame-retardant fibers are contained, the total content thereof is considered to be the content of the flame-retardant fiber.

[0017] When two or more types of flame-retardant fibers are used, the content of one of the flame-retardant fibers in the blended yarn may be 35% by weight or more, preferably 40% by weight or more, more preferably 45% by weight or more. The one type of flame-retardant fiber is preferably a carbonizing flame-retardant fiber.

[0018] The weight ratio of the flame-retardant fiber to the para-aramid fiber (flame-retardant fiber / para-aramid fiber) may be 35 / 65 to 65 / 35, preferably 40 / 60 to 60 / 40, more preferably 45 / 55 to 55 / 45, and even more preferably 48 / 52 to 52 / 48.

[0019] The blended yarn may contain fibers other than the flame-retardant fiber and the para-aramid fiber within a range that does not impair the effects of the present invention, and the total content of the flame-retardant fiber and the para-aramid fiber may be 90% by weight or more, preferably 95% by weight or more, more preferably 99% by weight or more, and even more preferably 100% by weight.

[0020] In one embodiment of the present invention, the blended yarn is made only of a carbonizable flame-retardant fiber having a limiting oxygen index of 25 or more and a para-aramid fiber, and the weight ratio of the carbonizable flame-retardant fiber to the para-aramid fiber (carbonizable flame-retardant fiber / para-aramid fiber) is 35 / 65 to 65 / 35. The blended yarn according to this embodiment ensures flame retardancy, has excellent heat resistance, and is excellent in texture.

[0021] In another embodiment of the present invention, the blended yarn is made only of flame-retardant polyvinyl alcohol fiber and para-aramid fiber, and the weight ratio of the flame-retardant polyvinyl alcohol fiber to the para-aramid fiber (flame-retardant polyvinyl alcohol fiber / para-aramid fiber) is 40 / 60 to 60 / 40. The blended yarn according to this embodiment not only ensures flame retardancy, is excellent in heat resistance and texture, but also has excellent dyeability in post-processing and excellent softness, so that flame-retardant clothing using such blended yarn is also excellent in comfort.

[0022] The blended yarn can be produced by mixing and spinning a flame-retardant fiber and a para-aramid fiber by a known method. From the viewpoint of achieving heat resistance and excellent texture, the blended yarn is preferably a spun yarn in which the flame-retardant fiber and the para-aramid fiber are uniformly mixed. Here, the term "uniform mixture" refers to the fibers being mixed and spun during blending, as opposed to a core-sheath spun yarn in which the flame-retardant fiber and the para-aramid fiber are arranged in the core and sheath, respectively. The uniformity of the blend of two or more fibers is not limited, and may be incomplete.

[0023] A woven or knitted fabric can be obtained by weaving or knitting the blended yarn. The woven or knitted fabric may contain the blended yarn, and may be woven or knitted using only the blended yarn, or may be woven or knitted by combining the blended yarn with other fibers, as long as the effects of the present invention are not impaired. The form of the woven or knitted fabric is not particularly limited and can be selected appropriately depending on the application, etc. For example, in the case of a woven fabric, the weave may be plain weave, twill weave, satin weave, etc. In the case of a knitted fabric, it may be flat knitting, circular knitting, warp knitting, etc., and a known knitting structure can be selected.

[0024] The woven or knitted fabric containing the blended yarn can be used as a constituent material for flame-retardant clothing. The flame-retardant clothing can be used as clothing to be worn when exposed to fire or heat, and can be suitably used, for example, as firefighting clothing worn at fire scenes, work clothes and protective clothing worn at various work sites such as factories where welding or electrical insulation is performed, chemical plants, and petroleum-related facilities, and as work clothes and rescue clothes worn by emergency personnel, lifeguards, members of the Self-Defense Forces, etc. [Example]

[0025] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0026] [Limiting Oxygen Index] The limiting oxygen index (LOI) of the flame-retardant fiber was calculated in accordance with JIS L 1091:1999 "Test method for flammability of textile products" (Method E).

[0027] [Heat resistance] The heat resistance of the fabrics obtained in the examples and comparative examples was tested in accordance with ISO 17493:2016 (JIS T 8023:2020) "Heat protective clothing and equipment - Test method for convective heat resistance using a hot air circulating oven" at a temperature of 260°C in a hot air circulating oven. The fabrics were observed after the test and evaluated according to the following criteria. ○: No significant deformation or hardening is observed ×: Significant deformation or hardening is observed

[0028] [Texture] The texture of the fabrics obtained in the Examples and Comparative Examples was evaluated according to the following criteria. 〇: Good texture (feels good on the skin) ×: Poor texture (rough)

[0029] [Example 1] A 30 count (cotton count) spun yarn (blended yarn) was obtained by uniformly mixing 50% by mass of "Kevlar (registered trademark)" manufactured by DuPont as a para-aramid fiber and 50% by mass of a flame-retardant polyvinyl alcohol fiber ("Binal" manufactured by Kuraray Co., Ltd.) as a carbonizing flame-retardant fiber. Two of these spun yarns were twisted together to form a two-ply yarn, which was then woven into a lattice plain weave.

[0030] [Example 2] A 30 count (cotton count) spun yarn (blended yarn) was obtained by uniformly mixing 60% by mass of "Kevlar (registered trademark)" manufactured by DuPont as a para-aramid fiber and 40% by mass of a flame-retardant polyvinyl alcohol fiber ("Binal" manufactured by Kuraray Co., Ltd.) as a carbonizing flame-retardant fiber. Two of these spun yarns were twisted together to form a two-ply yarn, which was then woven into a lattice plain weave.

[0031] [Example 3] A 30 count (cotton count) spun yarn (blended yarn) was obtained by uniformly mixing 40% by mass of "Kevlar (registered trademark)" manufactured by DuPont as a para-aramid fiber and 60% by mass of a flame-retardant polyvinyl alcohol fiber ("Binal" manufactured by Kuraray Co., Ltd.) as a carbonizing flame-retardant fiber. Two of these spun yarns were twisted together to form a two-ply yarn, which was then woven into a lattice plain weave.

[0032] [Comparative Example 1] A spun yarn of 30 count (cotton count) was obtained using 100% by mass of flame-retardant polyvinyl alcohol fiber ("Binal" manufactured by Kuraray Co., Ltd.) as the carbonizing flame-retardant fiber. Two of these spun yarns were ply-twisted to form a two-ply yarn, which was then woven into a lattice-pattern plain weave.

[0033] Comparative Example 2 100% by mass of "Kevlar (registered trademark)" manufactured by DuPont was used as the para-aramid fiber to obtain a spun yarn of 30 count (cotton count). Two of these spun yarns were ply-twisted to form a two-ply yarn, which was then woven into a lattice-pattern plain weave.

[0034] [Table 1]

[0035] As shown in Table 1, in Examples 1 to 3, a blended yarn containing a flame-retardant fiber having a specific limiting oxygen index and a para-aramid fiber in a specific content was used, and therefore the fabric obtained using such a blended yarn was excellent in both heat resistance and texture. Thus, it is expected that a blended yarn containing at least a flame-retardant polyvinyl alcohol fiber and a para-aramid fiber in a weight ratio of 40 / 60 to 60 / 40 can form a woven or knitted fabric excellent in both heat resistance and texture.

[0036] On the other hand, Comparative Example 1 has an excellent feel but poor heat resistance because it does not contain para-aramid fibers, and Comparative Example 2 uses para-aramid fibers, so it has high heat resistance but poor feel. [Industrial Applicability]

[0037] The blended yarn of the present invention can be used as a constituent fiber of woven or knitted fabrics for flame-retardant clothing, which can be suitably used as firefighting clothing worn at fire scenes, work clothes and protective clothing worn at various work sites such as factories where welding or electrical insulation is performed, chemical plants, and petroleum-related facilities, and work clothes and rescue clothes worn by emergency personnel, rescue teams, and members of the Self-Defense Forces, etc.

[0038] As described above, the preferred embodiment of the present invention has been described, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention, and such additions, modifications, or deletions are also included within the scope of the present invention.

Claims

1. A blended yarn containing a flame-retardant fiber having a limiting oxygen index of 25 or more and a para-aramid fiber, wherein the content of the para-aramid fiber is 35 to 65% by weight.

2. 2. The blended yarn according to claim 1, wherein the content of the flame-retardant fiber is 35 to 65% by weight.

3. 3. The blended yarn according to claim 1 or 2, wherein the flame-retardant fiber is a carbonizing flame-retardant fiber.

4. A woven or knitted fabric comprising the blended yarn of claim 1 or 2.

5. A flame-retardant garment comprising the woven or knitted fabric of claim 4.

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