(19)
(11)EP 3 536 836 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
11.09.2019 Bulletin 2019/37

(21)Application number: 17866832.3

(22)Date of filing:  25.10.2017
(51)Int. Cl.: 
D03D 15/12  (2006.01)
A41D 31/00  (2019.01)
D03D 15/00  (2006.01)
A41D 13/002  (2006.01)
D02G 3/04  (2006.01)
(86)International application number:
PCT/JP2017/038453
(87)International publication number:
WO 2018/084040 (11.05.2018 Gazette  2018/19)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
MA MD

(30)Priority: 01.11.2016 JP 2016214220
22.02.2017 JP 2017031094

(71)Applicant: Teijin Limited
Osaka-shi, Osaka 530-0005 (JP)

(72)Inventors:
  • TANAKA Kengo
    Osaka-shi Osaka 530-0005 (JP)
  • SHIMADA Hiroki
    Osaka-shi Osaka 530-0005 (JP)
  • IWASHITA Kenji
    Osaka-shi Osaka 530-0005 (JP)
  • YOSHIHARA Kenji
    Osaka-shi Osaka 530-0005 (JP)

(74)Representative: Cockerton, Bruce Roger 
Carpmaels & Ransford LLP One Southampton Row
London WC1B 5HA
London WC1B 5HA (GB)


(56)References cited: : 
  
      


    (54)FABRIC, METHOD FOR MANUFACTURING SAME, AND FIBER PRODUCT


    (57) The invention addresses the problem of providing a cloth that is excellent not only in flame retardancy and antistatic properties but also in appearance quality and preferably also has protection performance against electric arcs, a method for producing the same, and a textile product. A means for resolution is a cloth including a meta-type wholly aromatic polyamide fiber and an electrically conductive fiber, wherein both the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored.


    Description

    Technical Field



    [0001] The present invention relates to a cloth that is excellent not only in flame retardancy and antistatic properties but also in appearance quality and preferably also has protection performance against electric arcs, a method for producing the same, and a textile product.

    Background Art



    [0002] Conventionally, in garments worn by fire fighters, pilots, race drivers, workers at power companies and chemical companies, and the like, assuming contact with flames or high temperatures, a flame-retardant cloth using a wholly aromatic polyamide fiber (aramid fiber) has been used.

    [0003] In these garments, not only flame retardancy but also antistatic performance is required. Therefore, it has been proposed to mix an electrically conductive fiber, such as an electrically conductive aliphatic polyamide fiber (electrically conductive nylon fiber), into the cloth (e.g., PTL 1). When an electrically conductive fiber is mixed into a cloth, static electricity generated by the friction of the cloth is reduced, making it possible to prevent dust adhesion, harmful effects caused by discharge, ignition in an explosion-proof environment, and the like. In addition, it has been proposed to subject a flame-retardant cloth using a wholly aromatic polyamide fiber to a dyeing treatment (e.g., PTL 2 and PTL 3).

    [0004] However, an electrically conductive aliphatic polyamide fiber is not colored with a cationic dye, which is used in the case of dyeing a flame-retardant cloth using a wholly aromatic polyamide fiber. Therefore, there has been a problem in that the appearance quality of the flame-retardant cloth decreases.

    [0005] Meanwhile, those who work near electrical equipment and ambulance officers who deal with accidents near electrical equipment may be subconsciously exposed to electric arcs or flash fires, and there also is a demand for a cloth also having protection performance against electric arcs.

    Citation List


    Patent Literature



    [0006] 

    PTL 1: WO 2016/035638

    PTL 2: WO 2015/159749

    PTL 3: JP-A-2003-209776


    Summary of Invention


    Technical Problem



    [0007] The invention has been accomplished against the above background. An object thereof is to provide a cloth that is excellent not only in flame retardancy and antistatic properties but also in appearance quality and preferably also has protection performance against electric arcs, a method for producing the same, and a textile product.

    Solution to Problem



    [0008] The present inventors have conducted extensive research to achieve the above object. As a result, they have found that when a wholly aromatic polyamide fiber and an electrically conductive fiber, which can be colored with a same dye, are used, a cloth excellent not only in flame retardancy and antistatic properties but also in appearance quality can be obtained. As a result of further extensive research, they have accomplished the invention.

    [0009] Thus, the invention provides "a cloth including a meta-type wholly aromatic polyamide fiber and an electrically conductive fiber, wherein both the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored."

    [0010] At this time, it is preferable that the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber contain a same dye. At this time, it is preferable that the dye is a cationic dye. In addition, it is preferable that the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored a same color. In addition, it is preferable that the electrically conductive fiber is an electrically conductive acrylic fiber. In addition, it is preferable that the electrically conductive acrylic fiber is a sheath-core conjugate fiber. At this time, it is preferable that the electrically conductive acrylic fiber is a sheath-core conjugate fiber including a core part containing electrically conductive microparticles and a sheath part not containing electrically conductive microparticles. In addition, it is preferable that the cloth contains the electrically conductive fiber in an amount of 1 to 30 mass% relative to the cloth mass. In addition, it is preferable that the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are contained in the form of a blended yarn. In addition, it is preferable that the cloth further contains at least one selected from the group consisting of para-type wholly aromatic polyamide fibers, polyphenylene sulfide fibers, polyimide fibers, polybenzimidazole fibers, polybenzoxazole fibers, polyamideimide fibers, polyetherimide fibers, Pyromex®, and carbon fibers. In addition, it is preferable that the cloth has a woven fabric structure. In addition, it is preferable that a spun yarn containing the meta-type wholly aromatic polyamide fiber and an antistatic fiber is placed in each of warp and weft yarns. In addition, it is preferable that the cloth has a weight per unit within a range of 3.0 to 9.0 oz/yd2.

    [0011] It is preferably that the cloth of the invention has a frictional charge quantity of 7.0 µC/m2 or less as measured by JIS L1094-2014, C Method. In addition, it is preferable that the cloth of the invention has an afterflame time of 1.0 second or less in the flammability measurement according to JIS L1091-1992 A-4 Method (12-second flame application).

    [0012] In addition, the invention provides a textile product using the cloth described above and selected from the group consisting of protective garments, work garments, fireproof garments, camouflage uniforms, happi coats, and aprons.

    [0013] In addition, the invention provides a method for producing the cloth described above, including subjecting a cloth containing a meta-type wholly aromatic polyamide fiber and an electrically conductive fiber to dyeing processing. Advantageous Effects of Invention

    [0014] According to the invention, a cloth that is excellent not only in flame retardancy and antistatic properties but also in appearance quality and preferably also has protection performance against electric arcs, a method for producing the same, and a textile product are obtained.

    Description of Embodiments



    [0015] Hereinafter, embodiments of the invention will be described in detail. First, the meta-type wholly aromatic polyamide fiber (meta-type aramid fiber) used in the invention is a fiber made of a polymer, wherein 85 mol% or more of the repeating unit is m-phenyleneisophthalamide. The meta-type wholly aromatic polyamide may also be a copolymer containing a third component in an amount within a range of less than 15 mol%.

    [0016] Such a meta-type wholly aromatic polyamide can be produced by a conventionally known interfacial polymerization method. With respect to the polymerization degree of the polymer used, it is preferable that the intrinsic viscosity (I.V.) as measured with an N-methyl-2-pyrrolidone solution having a concentration of 0.5 g/100 ml is within a range of 1.3 to 1.9 dl/g.

    [0017]  The meta-type wholly aromatic polyamide may contain an alkylbenzenesulfonic acid onium salt. Preferred examples of alkylbenzenesulfonic acid onium salts include compounds such as a hexylbenzenesulfonic acid tetrabutylphosphonium salt, a hexylbenzenesulfonic acid tributylbenzylphosphonium salt, a dodecylbenzenesulfonic acid tetraphenylphosphonium salt, a dodecylbenzenesulfonic acid tributyltetradecylphosphonium salt, a dodecylbenzenesulfonic acid tetrabutylphosphonium salt, and a dodecylbenzenesulfonic acid tributylbenzylammonium salt. Among them, a dodecylbenzenesulfonic acid tetrabutylphosphonium salt and a dodecylbenzenesulfonic acid tributylbenzylammonium salt are particularly preferable because they are easy to obtain, have excellent thermal stability, and also have high solubility in N-methyl-2-pyrrolidone.

    [0018] In order to obtain a sufficient dye affinity improving effect, it is preferable that the content of the alkylbenzenesulfonic acid onium salt is within a range of 2.5 mol% or more (more preferably 3.0 to 7.0 mol%) relative to poly-m-phenylene isophthalamide.

    [0019] In addition, as a method for mixing poly-m-phenylene isophthalamide and an alkylbenzenesulfonic acid onium salt, a method in which poly-m-phenylene isophthalamide is mixed and dissolved in a solvent, and then an alkylbenzenesulfonic acid onium salt is dissolved in the solvent, is used, for example. The dope thus obtained is formed into a fiber by a conventionally known method.

    [0020] As the polymer used for the meta-type wholly aromatic polyamide fiber, for the purpose of improving the dyeing affinity and discoloration/fading resistance, for example, it is also possible that into an aromatic polyamide backbone having a repeating structural unit represented by the following formula (1), an aromatic diamine component or aromatic dicarboxylic acid halide component, which is different from a main unit of the repeating structure, is copolymerized as a third component to represent 1 to 10 mol% based on the total amount of repeating structural units in the aromatic polyamide.

            -(NH-Ar1-NH-CO-Ar1-CO) ...     formula (1)



    [0021] Here, Ar1 is a divalent aromatic group having a linking group in a position other than the meta position or the axially parallel direction.

    [0022] In addition, the following third components are also copolymerizable. Specific examples of aromatic diamines represented by formulae (2) and (3) include p-phenylenediamine, chlorophenylenediamine, methylphenylenediamine, acetylphenylenediamine, aminoanisidine, benzidine, bis(aminophenyl)ether, bis(aminophenyl)sulfone, diaminobenzanilide, and diaminoazobenzene. Specific examples of aromatic dicarboxylic acid dichlorides represented by formulae (4) and (5) include terephthalic acid chloride, 1,4-naphthalenedicarboxylic acid chloride, 2,6-naphthalenedicarboxylic acid chloride, 4,4'-biphenyldicarboxylic acid chloride, 5-chloroisophthalic acid chloride, 5-methoxyisophthalic acid chloride, and bis(chlorocarbonylphenyl)ether.

            H2N-Ar2-NH2 ...     formula (2)

            H2N-Ar2-Y-Ar2-NH2 ...     formula (3)

            XOC-Ar3-COX ...     formula (4)

            XOC-Ar3-Y-Ar3-COX ...     formula (5)



    [0023] Here, Ar2 is a divalent aromatic group different from Ar1, Ar3 is a divalent aromatic group different from Ar1, Y is at least one atom or functional group selected from the group consisting of an oxygen atom, a sulfur atom, and an alkylene group, and X is a halogen atom.

    [0024] In addition, from the standpoint that the dye exhaustion is good, and the color can be easily adjusted as intended even with a reduced amount of dye or under weak dyeing conditions, it is preferable that the crystallinity of the meta-type wholly aromatic polyamide fiber is 5 to 35%. Further, from the standpoint that the dye is less likely to be unevenly distributed on the surface, the discoloration/fading resistance is also high, and the practically necessary dimensional stability can also be ensured, the crystallinity is more preferably 15 to 25%.

    [0025] In addition, from the standpoint that the excellent flame retardancy of the meta-type wholly aromatic polyamide fiber is not impaired, it is preferable that the residual solvent content of the meta-type wholly aromatic polyamide fiber is 0.1 mass% or less (more preferably 0.001 to 0.1 mass%).

    [0026] The meta-type wholly aromatic polyamide fiber can be produced by the following method. In particular, by the method described below, the crystallinity and the residual solvent content can be made within the above ranges.

    [0027] The polymerization method for the meta-type wholly aromatic polyamide polymer is not particularly limited. For example, the solution polymerization method and the interfacial polymerization method described in JP-B-35-14399, U.S. Patent No. 3360595, JP-B-47-10863, and the like may be used.

    [0028]  The spinning solution is not particularly limited. It is possible to use an amide-based solvent solution containing an aromatic copolyamide polymer obtained by the solution polymerization or interfacial polymerization described above, for example, or it is also possible that the polymer is isolated from the polymerization solution, dissolved in an amide-based solvent, and used.

    [0029] Examples of amide-based solvents used herein include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide. N,N-dimethylacetamide is particularly preferable.

    [0030] When the copolymerized aromatic polyamide polymer solution obtained as above further contains an alkali metal salt or alkaline earth metal salt, the solution is further stabilized and becomes usable at higher concentrations and lower temperatures; therefore, this is preferable. The alkali metal salt or alkaline earth metal salt is preferably 1 mass% or less (more preferably 0.1 mass% or less) based on the total mass of the polymer solution.

    [0031] In a spinning/coagulation step, the spinning solution obtained above (meta-type wholly aromatic polyamide polymer solution) is extruded into a coagulation liquid and coagulated.

    [0032] The spinning apparatus is not particularly limited, and a conventionally known wet-spinning apparatus can be used. In addition, as long as wet spinning can be stably performed, there are no particular limitations on the number of spinning holes of the spinneret, their arrangement, the hole shape, and the like. For example, it is possible to use a multi-hole spinneret for staple fibers, in which the number of holes is 1,000 to 30,000 and the spinning hole diameter is 0.05 to 0.2 mm, or the like.

    [0033] In addition, it is preferable that the temperature of the spinning solution (meta-type wholly aromatic polyamide polymer solution) upon extrusion from the spinneret is within a range of 20 to 90°C.

    [0034] As a coagulation bath used to obtain the fiber, it is preferable to use an aqueous solution containing substantially no inorganic salt and having an amide-based solvent, preferably NMP, concentration of 45 to 60 mass% at a bath liquid temperature within a range of 10 to 50°C. When the amide-based solvent (preferably NMP) concentration is less than 45 mass%, this may result in a thick-skin structure, whereby the washing efficiency in a washing step decreases, making it difficult to reduce the residual solvent content of the fiber. Meanwhile, in the case where the amide-based solvent (preferably NMP) concentration is more than 60 mass%, uniform coagulation inside fibers may not be achieved, making it difficult, also in this case, to reduce the residual solvent content of the fiber. Incidentally, it is preferable that the time of fiber immersion in the coagulation bath is within a range of 0.1 to 30 seconds.

    [0035] Subsequently, the fiber is drawn to a draw ratio of 3 to 4 in a plastic drawing bath containing an aqueous solution having an amide-based solvent, preferably NMP, concentration of 45 to 60 mass% at a bath liquid temperature within a range of 10 to 50°C. After drawing, the fiber is thoroughly washed with an aqueous solution at 10 to 30°C having an NMP concentration of 20 to 40 mass% and then through a hot water bath at 50 to 70°C. The fiber after washing is subjected to a dry heat treatment at a temperature of 270 to 290°C.

    [0036] By such a production method, a meta-type wholly aromatic polyamide fiber that satisfies the above crystallinity and residual solvent content ranges can be obtained.

    [0037] In the meta-type wholly aromatic polyamide fiber, the fiber may be in the form of long fibers (multifilament) or short fibers. In particular, for blend-spinning with other fibers, short fibers having a fiber length of 25 to 200 mm (more preferably 30 to 150 mm) are preferable. In addition, it is preferable that the single-fiber fineness is within a range of 1 to 5 dtex.

    [0038] In the cloth of the invention, it is preferable that the mass ratio of the meta-type wholly aromatic polyamide fiber is within a range of 70 to 99 mass% (more preferably 75 to 95 mass%) relative to the cloth mass. When the mass ratio of the meta-type wholly aromatic polyamide fiber is lower than this range, the flame retardancy of the cloth may decrease. Conversely, when the mass ratio of the meta-type wholly aromatic polyamide fiber is higher than this range, because the mass ratio of the electrically conductive fiber decreases, the antistatic properties may decrease.

    [0039] Meanwhile, as the electrically conductive fiber, an electrically conductive acrylic fiber is preferable. When the cloth contains a meta-type wholly aromatic polyamide fiber and an electrically conductive acrylic fiber, by dyeing the cloth with a cationic dye, both the meta-type wholly aromatic polyamide fiber and the electrically conductive acrylic fiber are dyed a deep color, and also the entire cloth is uniformly dyed. At this time, it is preferable that the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored a same color. Here, it is preferable that the hue difference between the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber is ΔE 3 or less.

    [0040] As the electrically conductive acrylic fiber, a fiber obtained by kneading electrically conductive carbon into an acrylic fiber, a sheath-core conjugate fiber including a core part containing electrically conductive microparticles and a sheath part not containing electrically conductive microparticles, or the like is preferable. In particular, a sheath-core conjugate fiber (or eccentric sheath-core conjugate fiber), in which the sheath part is made of acrylic not containing electrically conductive microparticles, while the core part is made of an electrically conductive carbon-containing polymer, or the like is preferable. When such an electrically conductive acrylic fiber is contained in the cloth, static electricity generated by the friction of the cloth can be reduced. As a result, problems such as dust adhesion, harmful effects caused by discharge, and ignition in an explosion-proof environment can be reduced.

    [0041] As the electrically conductive acrylic fiber, for example, the fiber described in JP-A-2009-221632 is preferable. That is, the fiber is a sheath-core electrically conductive acrylic fiber including a core part containing electrically conductive microparticles and a sheath part not containing electrically conductive microparticles, wherein the core-sheath ratio is 15/85 to 50/50, the electrically conductive microparticle content of the core part is 20 to 60 mass%, and the single-fiber resistivity is 101 to 106 Ω·cm.

    [0042] In the electrically conductive fiber, the fiber may be in the form of long fibers (multifilament) or short fibers. In particular, for blend-spinning with other fibers, short fibers having a fiber length of 25 to 200 mm (more preferably 30 to 150 mm) are preferable. In addition, it is preferable that the single-fiber fineness is within a range of 1 to 5 dtex.

    [0043] In the cloth of the invention, it is preferable that the mass ratio of the electrically conductive fiber is within a range of 1 to 30 mass% (more preferably 1 to 20 mass%) relative to the cloth mass. When the weight ratio of the electrically conductive fiber is lower than this range, the antistatic properties of the cloth may decrease. Conversely, when the mass ratio of the electrically conductive fiber is higher than this range, because the mass ratio of the meta-type wholly aromatic polyamide fiber decreases, the flame retardancy may decrease.

    [0044] The cloth of the invention may be composed only of the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber, but may further contain at least one selected from the group consisting of para-type wholly aromatic polyamide fibers, polyphenylene sulfide fibers, polyimide fibers, polybenzimidazole fibers, polybenzoxazole fibers, polyamideimide fibers, polyetherimide fibers, Pyromex®, and carbon fibers.

    [0045] For example, when a para-type wholly aromatic polyamide fiber is contained in the cloth, the strength of the cloth (tensile strength, etc.) improves; therefore, this is preferable. At this time, it is preferable that the mass ratio of the para-type wholly aromatic polyamide fiber is within a range of 1 to 10 mass% relative to the cloth mass.

    [0046] The cloth of the invention may further contain a polyester fiber. A polyester fiber may be contained in the cloth. At this time, it is preferable that the mass ratio of the polyester fiber is within a range of 1 to 10 mass% relative to the cloth mass.

    [0047] Here, in order to obtain a cloth excellent not only in flame retardancy and antistatic properties but also in appearance quality, it is preferable that these fibers are blend-spun and contained in the form of a blended yarn in the cloth. At this time, it is preferable that the fiber length of each fiber is 25 to 200 mm (more preferably 30 to 150 mm) . Incidentally, the fiber lengths of fibers may be the same as or different from each other.

    [0048] In the invention, in order to obtain a high-quality appearance, it is important that both the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored. In particular, it is preferable that the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored a same color (ΔE is 3 or less).

    [0049] Here, it is preferable that the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber contain a same dye. In particular, it is preferable that the dye is a cationic dye.

    [0050] A cationic dye refers to a water-soluble dye soluble in water and having a group that exhibits basicity, and has been widely used in the dyeing of, for example, acrylic fibers, natural fibers, or cationic-dyeable polyester fibers. Examples of cationic dyes include diacrylic methane dyes, triacrylic methane dyes, quinoneimine (azine, oxazine, thiazine) dyes, xanthene dyes, methine dyes (polymethine, azamethine), heterocyclic azo dyes (thiazole azo, triazole azo, benzothiazole azo), and anthraquinone dyes. In addition, in recent years, dispersed cationic dyes obtained by blocking basic groups are also known, and both can be used. Among them, azo dyes are preferable. Preferred examples of azo dyes include C.I. Basic Blue 54, C.I. Basic Blue 3, C.I. Basic Red 29, and C.I. Basic Yellow 67.

    [0051] In the invention, the method for producing the cloth is not particularly limited, and any known methods may be used. For example, at least a meta-type wholly aromatic polyamide fiber and an electrically conductive fiber are blended into a spun yarn.

    [0052] At this time, in terms of resistance to yarn breakage, strength, and the like, the fineness of the spun yarn (count) is preferably a cotton count (Ecc) of 20 to 80. The number of single yarns is preferably 60 or more. The raw cotton single-fiber fineness is preferably 3.0 dtex or less (more preferably 0.001 to 3.0 dtex). The twist coefficient (first twist coefficient) of the spun yarn is preferably within a range of 3.6 to 4.2 (more preferably 3.8 to 4.0). With an increase in the twist coefficient, the fluff is settled, and the pilling resistance of the cloth improves; on the other hand, the spun yarn becomes rigid, whereby the elongation may decrease, resulting in a decrease in the tear strength of the cloth, or the cloth may be hardened. Incidentally, the twist coefficient is expressed by the following equation.



    [0053] The spinning method for the spun yarn may be innovative spinning, such as ring spinning, MTS, MJS, or MVS, or an ordinary spinning method, such as ring spinning. The twist direction may be Z-direction or S-direction.

    [0054] Next, the spun yarn is twist-set as necessary (vacuum steam setting), and then, as necessary, two or more of the spun yarns (preferably two to four yarns, particularly preferably two yarns) are aligned, combined, and plied. As twisting machines used for plying, twisting machines such as an up-twister, a covering machine, an Italian twisting machine, and a double twister can be mentioned.

    [0055] At this time, the twisting direction in plying (second twisting) is the twist-adding direction. For example, in the case where the twist direction of the spun yarn is Z-twisted, twisting is performed in the same direction, that is, in the Z-direction. In addition, the number of twists is preferably 2,000/m or more, more preferably 2,100 to 3,000/m, and particularly preferably 2,300 to 2,800/m. In the case where the number of twists is less than 2,000/m, after twist setting and untwisting, the spun yarn may not be in coiled form.

    [0056] Next, the plied yarn is twist-set (the same high-pressure vacuum steam setting as used for twist-setting a conventional aramid double ply yarn). In the case where firm twist setting has to be imparted, the number of times of twist setting may be increased, or the twist setting temperature or setting time may be changed. For example, the setting temperature may be 115 to 125°C, the setting time may be 20 to 40 minutes, and the number of times may be 1 to 3. A higher setting temperature or a longer setting time results in better setting properties and thus is more preferable. The setting properties can be further enhanced by increasing the number of times of twist setting, prolonging the treatment time, or raising the temperature. Considering the production control (the safety of work control, quality control, etc.) and the production/processing cost, it is preferable to prolong the treatment time. In addition, a higher degree of vacuum results in improved quality and thus is preferable.

    [0057] Next, the twist-set plied yarn is untwisted (twisted in the direction opposite to the twist direction in plying), and heat-set as necessary. At this time, the number of twists in untwisting is preferably within a range of 70 to 90% of the number of twists in plying. When untwisting is performed with the number of twists being within this range, a spun yarn in coiled form having stretchability is obtained. In such a spun yarn in coiled form, in order to obtain excellent stretchability, it is preferable that the number of twists is within a range of 200 to 860/m.

    [0058] In addition, the raw cotton used for the spun yarn may be dyed (yarn-dyed) raw cotton or spun-dyed raw cotton, or it is also possible to use raw cotton that has been subjected to a functionalization treatment (sweat absorption, quick dry, soil resistance, flame retardancy, UV absorption, etc.).

    [0059] In the cloth of the invention, the structure of the cloth is not particularly limited, and may be a woven fabric, a knitted fabric, or a nonwoven fabric. However, in terms of flame retardancy, fire resistance, cloth strength, and the like, a woven fabric is preferable. At this time, as the woven fabric structure, a plain structure, a twill structure, a satin structure, a double fabric, and the like are preferable.

    [0060] As the density of the woven fabric, in order to obtain excellent protection performance against electric arcs, it is preferable that the warp density is 50 yarns/2.54 cm or more and the weft density is 50 yarns/2.54 cm or more (more preferably the warp density is 60 yarns/2.54 cm or more and the weft density is 60 yarns/2.54 cm or more, and particularly preferably the warp density is 60 to 80 yarns/2.54 cm and the weft density is 60 to 80 yarns/2.54 cm or more).

    [0061] In addition, when a spun yarn containing a meta-type aromatic polyamide fiber and an antistatic fiber is placed in each of the warp and weft yarns of the woven fabric, the protection performance against electric arcs improves; therefore, this is preferable.

    [0062] The cloth of the invention can be knitted or woven in the usual manner using the spun yarn described above. At this time, it is preferable that the spun yarn is woven as a single yarn or a double ply yarn using a rapier loom or the like into a twill weave, a plain weave, or a like structure. A knitted fabric and a nonwoven fabric are also possible.

    [0063] Knitting or weaving is preferably followed by post-processing. Specific examples of post-processing steps include scouring, drying, relaxing, singeing, dyeing, and functionalization treatments.

    [0064] Here, as the dyeing processing, it is preferable that the dyeing processing is performed in a dyeing bath containing the cationic dye described above. At this time, a method in which dyeing is performed at 115 to 135°C, followed by a reduction treatment and drying, can be preferably employed, for example, but the method is not limited thereto.

    [0065] In addition, in the dyeing processing, it is preferable that a carrier agent is used, and the dyeing treatment is performed in one bath containing the cationic dye and the carrier agent. In addition, when the cloth is treated with a special surfactant before the cationic dyeing, deep dyeing in open-width dyeing can be achieved.

    [0066] It is preferable that the carrier agent is, for example, at least one selected from DL-β-ethylphenethyl alcohol, 2-ethoxybenzyl alcohol, 3-chlorobenzyl alcohol, 2,5-dimethylbenzyl alcohol, 2-nitrobenzyl alcohol, p-isopropylbenzyl alcohol, 2-methylphenethyl alcohol, 3-methylphenethyl alcohol, 4-methylphenethyl alcohol, 2-methoxybenzyl alcohol, 3-iodobenzyl alcohol, cinnamic alcohol, p-anisyl alcohol, and benzhydrol. As specific products, benzyl alcohol, DOWANOL PPH manufactured by Dow Chemical Company, and CINDYE DNK manufactured by BOZZETTO are preferable. In addition, in terms of further improving the dye affinity, it is preferable to use benzyl alcohol, particularly 2,5-dimethylbenzyl alcohol or 2-nitrobenzyl alcohol.

    [0067]  The amount of carrier agent is preferably 1 to 10 parts by weight (more preferably 1 to 5 parts by weight) per 100 parts by weight of the meta-type wholly aromatic polyamide fiber.

    [0068] The scouring or relaxing treatment may be an open-width treatment or a jet scouring/relaxing treatment. Specifically, it is a method in which the cloth is treated with an open-width non-tension machine in continuous scouring or continuous drying. Such a method uses, for example, a Sofcer scouring machine, a tenter and drying machine, a shrink surfer, a short loop, a Luciole dryer, or the like. In some cases, the scouring or relaxing step may be omitted.

    [0069] In addition, for improving other properties, shaving and/or singeing may also be performed. Further, it is also possible to additionally apply other various processes for imparting the functions of a sweat absorbent, a water repellent, a heat storage agent, UV shielding, an antistatic agent, an antibacterial agent, a deodorant, an insect repellent, a mosquito repellent, a phosphorescent agent, a retroreflective agent, and the like. The woven or knitted fabric used may be a spun-dyed product, a yarn-dyed product, or a piece-dyed product.

    [0070] Preferred examples of sweat absorbents include polyethylene glycol diacrylate, a polyethylene glycol diacrylate derivative, a polyethylene terephthalate-polyethylene glycol copolymer, and a water-soluble polyurethane.

    [0071] As methods for imparting a sweat absorbent to the cloth, a method that performs a padding treatment, a method in which the cloth is treated at the time of dyeing processing in the same bath as the dyeing liquid, and the like can be mentioned.

    [0072] In the cloth thus obtained, it is preferable that the thickness of the cloth is 0.30 mm or more (more preferably 0.35 to 0.50 mm). When the thickness of the cloth is less than 0.30 mm, the protection performance against electric arcs may decrease. Conversely, when the thickness of the cloth is more than 0.50 mm, the lightweight properties and wearing comfort may decrease.

    [0073] In addition, it is preferable that the weight per unit of the cloth is within a range of 3.0 to 9.0 oz/yd2 (more preferably 5.0 to 9.0 oz/yd2). When the weight per unit of the cloth is lower than this range, the protection performance against electric arcs may decrease. Conversely, when the weight per unit of the cloth is higher than this range, the lightweight properties and wearing comfort may decrease.

    [0074] The cloth of the invention has the above configuration, and thus is excellent not only in flame retardancy and antistatic properties but also in appearance quality and further has protection performance against electric arcs.

    [0075] In the cloth of the invention, in the case where an electrically conductive acrylic fiber including a core part containing electrically conductive microparticles and a sheath part not containing electrically conductive microparticles is contained, the electrically conductive microparticles contained in the core part absorb the irradiation energy of electric arc flash and suppress the energy that permeates the cloth. Accordingly, such a cloth has excellent protection performance for the human body. The sheath part is made of an acrylic polymer not containing electrically conductive microparticles, and thus can be dyed with the same cationic dye as for the meta-type wholly aromatic polyamide fiber.

    [0076] Here, as antistatic properties, it is preferable that the frictional charge quantity measured by JIS L1094-2014, C Method, is 7.0 µC/m2 or less (more preferably 0.1 to 4.0 µC/m2). In addition, as flame retardancy, it is preferable that the afterflame time in the flammability measurement according to JIS L1091-1992, A-4 Method (12-second flame application), is 1.0 second or less. In addition, it is preferable that the ATPV value in Arc Resistance Test ASTM F1959-1999 is 8.0 cal/cm2 or more (preferably 8.0 to 12.0 cal/cm2). In addition, it is preferable that the limiting oxygen index (LOI) is 26 or more.

    [0077] In addition, the invention provides a textile product using the cloth described above and selected from the group consisting of protective garments, work garments, fireproof garments, camouflage uniforms, happi coats, and aprons.

    [0078] The textile product uses the cloth described above, and thus is excellent not only in flame retardancy and antistatic properties but also in appearance quality and further has protection performance against electric arcs.

    [Examples]



    [0079] Hereinafter, the invention will be described in detail with reference to examples, but the invention is not limited thereto. Incidentally, in the examples, the properties were measured by the following methods.

    (1) Flame Retardancy of Cloth



    [0080] The afterflame time was measured by the flammability measurement according to JIS L1091-1992, A-4 Method (12-second flame application).

    (2) Residual Solvent Content



    [0081] About 8.0 g of a raw fiber was collected, dried at 105°C for 120 minutes, and then allowed to cool in a desiccator, and the fiber mass (M1) was measured. Subsequently, the fiber was subjected to reflux extraction in methanol for 1.5 hours using a Soxhlet extractor to extract the amide-based solvent contained in the fiber. The fiber after extraction was taken out, vacuum-dried at 150°C for 60 minutes, and then allowed to cool in a desiccator, and the fiber mass (M2) was measured. Using the obtained M1 and M2, the content of residual solvent in the fiber (amide-based solvent mass) was calculated using the following equation.


    (3) Crystallinity



    [0082] An about 1 mm-diameter bundle of raw fibers was mounted on a fiber sample table and subjected to measurement of diffraction profile using an X-ray diffraction apparatus (RINT TTRIII manufactured by Rigaku Corporation). The measurement conditions were as follows: Cu-Kα radiation source (50 kV, 300 mA), scanning angle range: 10 to 35°, continuous measurement, measurement width: 0.1°, scanning at 1°/min. From the measured diffraction profile, air scattering and incoherent scattering were corrected by linear approximation to give the total scattering profile. Next, the amorphous scattering profile was subtracted from the total scattering profile to give the crystal scattering profile. The crystallinity was determined from the integrated intensity of the crystal scattering profile (crystal scattering intensity) and the integrated intensity of the total scattering profile (total scattering intensity) using the following equation.


    (4) Dye Affinity



    [0083] Color measurement was performed using a Macbeth spectrophotometer (Color-Eye 3100) to determine ΔE.

    (5) Antistatic Properties



    [0084] The frictional charge quantity was measured by JIS L1094-2014, C Method. 7.0 µC/m2 or less was rated as acceptable.

    (6) Weight per Unit



    [0085] Measurement was performed in accordance with JIS L1096.

    (7) ATPV Value



    [0086] The ATPV value was measured in accordance with Arc Resistance Test ASTM F1959-1999. 8.0 cal/cm2 or more is rated as acceptable (Level 2 satisfied).

    [Production of Meta-Type Wholly Aromatic Polyamide Fiber]



    [0087] A meta-type wholly aromatic polyamide fiber was prepared by the following method.

    [0088] 20.0 parts by mass of a polymetaphenylene isophthalamide powder having an intrinsic viscosity (I.V.) of 1.9 produced by an interfacial polymerization method based on the method described in JP-B-47-10863 was suspended in 80.0 parts by mass of N-methyl-2-pyrrolidone (NMP) cooled to -10°C, thereby forming a slurry. Subsequently, the suspension was heated to 60°C for dissolution to give a transparent polymer solution. A powder of 2-[2H-benzotriazol-2-yl]-4-6-bis(1-methyl-1-phenylethyl)ph enol (solubility in water: 0.01 mg/L) in an amount of 3.0 mass% relative to the polymer was mixed with and dissolved in the polymer solution, and the mixture was defoamed under reduced pressure to give a spinning solution (spinning dope).

    [Spinning/Coagulation Step]



    [0089] The above spinning dope was discharged and spun from a spinneret having 500 0.07-mm-diameter holes into a coagulation bath at a bath temperature of 30°C. The composition of the coagulation liquid was water/NMP = 45/55 (parts by mass), and the dope was discharged and spun into the coagulation bath at a yarn speed of 7 m/min.

    [Drawing Step in Plastic Drawing Bath]



    [0090] Subsequently, drawing was performed to a draw ratio of 3.7 in a plastic drawing bath at a temperature of 40°C having a composition of water/NMP = 45/55.

    [Washing Step]



    [0091] After drawing, washing was performed in a bath at 20°C having water/NMP = 70/30 (immersion length: 1.8 m) and then in a water bath at 20°C (immersion length: 3.6 m), followed by thorough washing through a hot water bath at 60°C (immersion length: 5.4 m).

    [Dry Heat Treatment Step]



    [0092] The fiber after washing was subjected to a dry heat treatment using a hot roller having a surface temperature of 280°C to give a meta-type wholly aromatic polyamide fiber.

    [Properties of Raw Fiber]



    [0093] The obtained meta-type wholly aromatic polyamide fiber (meta-aramid fiber) had the following properties: fineness: 1.7 dtex, residual solvent content: 0.08 mass%, crystallinity: 19%. The obtained raw fiber was crimped and cut into short fibers of 51 mm in length (raw cotton).

    [Example 1]



    [0094] Using the above meta-type wholly aromatic polyamide fiber, a para-type wholly aromatic polyamide fiber having a single-fiber fineness of 1.7 dtex and a fiber length of 50 mm (manufactured by Teijin Aramid, trade name "Twaron"), and an electrically conductive acrylic fiber having a single-fiber fineness of 3.3 dtex and a fiber length of 38 mm (manufactured by Mitsubishi Chemical Corporation, trade name "COREBRID", eccentric sheath-core electrically conductive acrylic fiber; sheath part: acrylic/core part: electrically conductive carbon-containing polymer), a spun yarn of 1/68 yarn count was formed such that the meta-type wholly aromatic polyamide fiber: 93 mass%, the para-type wholly aromatic polyamide fiber: 5 mass%, and the electrically conductive acrylic fiber: 2 mass%, and a double ply yarn plied yarn was obtained.

    [0095] Next, the yarn was placed in each of warp and weft yarns, and a plain-structure woven fabric having a warp density of 57 yarns/2.54 cm and a weft density of 50 yarns/2.54 cm was woven.

    [0096] Using a jet dyeing machine (high-temperature circular dyeing machine manufactured by Hisaka Works, Ltd.), the obtained undyed woven fabric (gray fabric) was treated in a dye bath containing a cationic dye (manufactured by Nippon Kayaku Co., Ltd., Kayacryl Red GL-ED, 15% owf) and a carrier agent (manufactured by Dow Chemical Company, DOWANOL PPH, 40 g/L). The temperature was raised from ambient, and the fabric was dyed at 130°C for 60 minutes.

    [0097] The obtained dyed cloth had excellent appearance quality with a deep color and no color non-uniformity. In addition, the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber were colored a same color, and the hue difference ΔE between the two was 3 or less. In addition, the frictional charge quantity was as excellent as 3.3 µC/m2. In addition, the afterflame time was 0 second, indicating excellent flame retardancy.

    [Example 2]



    [0098] A dyed cloth was obtained in the same manner as in Example 1, except that a spun yarn of 1/68 yarn count was formed such that the meta-type wholly aromatic polyamide fiber: 80 mass%, the para-type wholly aromatic polyamide fiber: 5 mass%, and the electrically conductive acrylic fiber: 15 mass%.

    [0099] The obtained dyed cloth had excellent appearance quality with a deep color and no color non-uniformity. In addition, the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber were colored a same color, and the hue difference ΔE between the two was 3 or less. In addition, the frictional charge quantity was as excellent as 1.4 µC/m2. In addition, the afterflame time was 0 second, indicating excellent flame retardancy.

    [Comparative Example 1]



    [0100] A dyed cloth was obtained in the same manner as in Example 1, except that an electrically conductive aliphatic polyamide fiber having a single-fiber fineness of 4.5 dtex and a fiber length of 51 mm (eccentric sheath-core electrically conductive nylon fiber; sheath part: Nylon 6/core part: white metal compound) was used as an electrically conductive fiber.

    [0101] In the obtained dyed cloth, although the frictional charge quantity was as excellent as 2.4 µC/m2, with respect to the appearance quality, the electrically conductive aliphatic polyamide fiber was not colored, resulting in color non-uniformity. In addition, the afterflame time was 0 second, indicating excellent flame retardancy.

    [Example 3]



    [0102] Spun yarns (first-twisted in the Z-direction, the number of twists: 800 to 950/m, cotton count: 40/1) each made of a polymetaphenylene isophthalamide fiber (Teijinconex® neo (trade name) manufactured by Teijin Limited, single-fiber fineness: 1.7 dtex, fiber length: 51 mm), an electrically conductive acrylic fiber (COREBRID (trade name) manufactured by Mitsubishi Chemical Corporation), and a para-type wholly aromatic polyamide fiber (Twaron® TW1072 manufactured by Teijin Aramid, single-fiber fineness: 1.7 dtex, fiber length: 51 mm) uniformly blended in a blending ratio of 85/10/5 (mass%) in the above order were combined, twisted using a double twister (900 twists/m in the S-direction), and then, as twist setting, steam-set at 120°C × 30 min, thereby giving a 2-ply yarn.

    [0103]  In addition, a 3-ply yarn formed by adding an electrically conductive yarn (B-TCF U300HX of Teijin Limited, total fineness: 31 dtex/5 fil) to the above combined spun yarns was obtained in the same manner.

    [0104] Subsequently, using the 2-ply yarn and the 3-ply yarn, the 3-ply yarn was placed at a pitch of 2.02 cm wide (the 3-ply yarn corresponds to about 2 mass% of the warp yarn) and creeled for warping. The obtained warp beam was subjected to sizing, leasing, and threading as warp yarn preparation. In addition, the 2-ply yarn was used as a weft yarn.

    [0105] Next, a 2/2 twill-structure woven fabric was woven at a warp density of 69 yarns/2.54 cm and a weft density of 62 yarns/2.54 cm.

    [0106] The obtained gray fabric was unrolled and sewn in the usual manner, and, using an open-width non-tension scouring machine (Sofcer), subjected to desizing, scouring, cylinder drying, singeing, and dyeing, followed by finish setting (180°C × 45 to 90 sec), thereby giving a finished textile having a weight per unit of 5.4 oz/yd2.

    [0107] Subsequently, the cloth was subjected to dyeing processing under the following conditions, and the polymetaphenylene isophthalamide fiber and the electrically conductive acrylic fiber contained in the cloth were colored.

    (Dyeing Processing Conditions)



    [0108] 

    Cationic dye: manufactured by Nippon Kayaku, trade name: Kayacryl Red GL-ED, 6.0% owf, 40 g/L swelling agent, 3 cc/L acetic acid, 1 cc/L dispersant, 25 g/L sodium nitrate

    Bath ratio: 1:20

    Temperature × Time: 130°C × 60 minutes

    The ATPV value was 8.7 cal/cm2, that is, acceptable (Level 2 satisfied).


    [Example 4]



    [0109] The same procedure as in Example 3 was performed, except that the para-type wholly aromatic polyamide fiber (Twaron® TW1072 manufactured by Teijin Aramid, single-fiber fineness: 1.7 dtex, fiber length: 51 mm) was replaced with a copolyparaphenylene-3,4' oxydiphenylene terephthalamide (PPODPA) fiber (Technora® manufactured by Teijin Limited). The ATPV value was 8.9 cal/cm2, that is, acceptable (Level 2 satisfied).

    [Example 5]



    [0110] The same treatment as in Example 3 was performed, except that the polymetaphenylene isophthalamide fiber (Teijinconex® neo (trade name) manufactured by Teijin Limited, single-fiber fineness: 1.7 dtex, fiber length: 51 mm) was replaced with a polymetaphenylene isophthalamide fiber (Teijinconex® FRNB3 manufactured by Teijin Limited, single-fiber fineness: 1.7 dtex, fiber length: 51 mm). The ATPV value was 8.9 cal/cm2, that is, acceptable (Level 2 satisfied).

    [Example 6]



    [0111] The same procedure as in Example 3 was performed, except that a 1/1 plain woven fabric was woven at the following weaving design density: a warp density of 62 yarns/2.54 cm and a weft density of 52 yarns/2.54 cm. A finished textile having a weight per unit of 4.5 oz/yd2 was thus obtained and evaluated in the same manner. The ATPV value was 6.7 cal/cm2, that is, unacceptable.

    [Comparative Example 2]



    [0112] The same treatment and evaluation as in Example 3 were performed, except that the fiber materials and the blending amounts were changed such that the electrically conductive acrylic fiber was 0 wt%. The ATPV value was 7.8 cal/cm2, that is, unacceptable.

    Industrial Applicability



    [0113] According to the invention, a cloth that is excellent not only in flame retardancy and antistatic properties but also in appearance quality and preferably also has protection performance against electric arcs, a method for producing the same, and a textile product are provided. The industrial value thereof is extremely high.


    Claims

    1. A cloth comprising a meta-type wholly aromatic polyamide fiber and an electrically conductive fiber, wherein
    both the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored.
     
    2. The cloth according to claim 1, wherein the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber contain a same dye.
     
    3. The cloth according to claim 2, wherein the dye is a cationic dye.
     
    4. The cloth according to any one of claims 1 to 3, wherein the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are colored a same color.
     
    5. The cloth according to any one of claims 1 to 4, wherein the electrically conductive fiber is an electrically conductive acrylic fiber.
     
    6. The cloth according to claim 5, wherein the electrically conductive acrylic fiber is a sheath-core conjugate fiber including a core part containing electrically conductive microparticles and a sheath part not containing electrically conductive microparticles.
     
    7. The cloth according to any one of claims 1 to 6, which contains the electrically conductive fiber in an amount of 1 to 30 mass% relative to the cloth mass.
     
    8. The cloth according to any one of claims 1 to 7, wherein the meta-type wholly aromatic polyamide fiber and the electrically conductive fiber are contained in the form of a blended yarn.
     
    9. The cloth according to any one of claims 1 to 8, further comprising at least one selected from the group consisting of para-type wholly aromatic polyamide fibers, polyphenylene sulfide fibers, polyimide fibers, polybenzimidazole fibers, polybenzoxazole fibers, polyamideimide fibers, polyetherimide fibers, Pyromex®, and carbon fibers.
     
    10. The cloth according to any one of claims 1 to 9, which has a woven fabric structure.
     
    11. The cloth according to claim 10, wherein a spun yarn containing the meta-type wholly aromatic polyamide fiber and an antistatic fiber is placed in each of warp and weft yarns.
     
    12. The cloth according to any one of claims 1 to 11, which has a weight per unit within a range of 3.0 to 9.0 oz/yd2.
     
    13. The cloth according to any one of claims 1 to 12, which has a frictional charge quantity of 7.0 µC/m2 or less as measured by a JIS L1094-2014 C method.
     
    14. The cloth according to any one of claims 1 to 13, which has an afterflame time of 1.0 second or less in a flammability measurement according to JIS L1091-1992 A-4 Method (12-second flame application).
     
    15. A textile product comprising the cloth according to any one of claims 1 to 14 and selected from the group consisting of protective garments, work garments, fireproof garments, camouflage uniforms, happi coats, and aprons.
     
    16. A method for producing the cloth according to claim 1, comprising subjecting a cloth containing a meta-type wholly aromatic polyamide fiber and an electrically conductive fiber to dyeing processing.
     











    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description