Flame-retardant cloth and work wear

Abstract

One or more embodiments of the present invention relate to a flame-retardant cloth that contains 30 to 60% by mass of modacrylic fibers, 20 to 50% by mass of cellulose-based fibers and 10 to 20% by mass of aramid fibers, and also contains a compound containing tin and zinc in an amount of 1.4 to 5.0% by mass relative to the entire mass of the cloth. According to this configuration, a flame-retardant cloth that is prevented from the reduction of tear strength after burning and is improved in flame retardancy and a work wear that contains the flame-retardant cloth are provided.

Description

Flame-retardant fabrics and workwear

[0001] The present invention relates to a flame-retardant fabric that exhibits high flame retardancy in a combustion test and to work clothes containing the same.

[0002] Combinations of modacrylic fibers with other fibers, such as cellulosic fibers, are commonly used, particularly in the field of workwear. For example, Patent Document 1 describes a flame-retardant workwear fabric that includes a modacrylic fiber containing an antimony compound and a cellulosic fiber containing a phosphorus compound. Patent Document 2 also describes the use of modacrylic fibers and cellulosic fibers in combination with high-strength aramid fibers.

[0003] International Publication No. 2015 / 025948 Special Publication No. 2017-525867

[0004] However, when modacrylic fibers containing an antimony compound are used in combination with aramid fibers, there is a risk that the tear strength after combustion will decrease and the flame retardancy will be poor.

[0005] In order to solve the above-mentioned problems of the conventional art, the present invention provides a flame-retardant fabric and work clothes with improved flame retardancy by suppressing the decrease in tear strength after combustion.

[0006] One or more embodiments of the present invention relate to a flame-retardant fabric comprising 30 to 60% by weight of modacrylic fiber, 20 to 50% by weight of cellulosic fiber, and 10 to 20% by weight of aramid fiber, and comprising 1.4 to 5.0% by weight of a compound containing tin and zinc, based on the total weight of the fabric.

[0007] One or more embodiments of the present invention relate to workwear comprising the flame-retardant fabric.

[0008] According to the present invention, a flame-retardant fabric having improved flame retardancy by suppressing a decrease in tear strength after combustion, and work clothes including the same are provided.

[0009] The inventors of the present invention conducted extensive research to solve the problem of decreased post-combustion tear strength, increased char length, and decreased flame retardancy when modacrylic fiber containing an antimony compound is used in combination with aramid fiber. As a result, they found that by using a compound containing tin and zinc as a flame retardant and adding a predetermined amount of this compound to a fabric containing modacrylic fiber, aramid fiber, and cellulosic fiber, the post-combustion tear strength of the fabric is increased and the post-combustion char length of the fabric is shortened. In particular, by using modacrylic fiber containing a compound containing tin and zinc in combination with aramid fiber and cellulosic fiber, the post-combustion tear strength of the fabric is likely to be increased and the post-combustion char length of the fabric is likely to be shortened. When modacrylic fibers containing antimony compounds are used, the aramid fibers are damaged by antimony gas derived from the modacrylic fibers during combustion, resulting in a decrease in tear strength after combustion. However, when compounds containing tin and zinc are used, the aramid fibers are not damaged, so the tear strength of the fabric after combustion does not decrease and the char length of the fabric after combustion is presumably shortened. However, the present invention is not bound by this presumption. Although the reason is unclear, this effect is surprisingly unique to the use of a compound containing tin and zinc, such as a zinc stannate compound, as a flame retardant. The use of a combination of a compound containing tin but not zinc and a compound containing zinc but not tin as a flame retardant does not result in an improvement in the flame retardancy of fabrics containing modacrylic fibers, aramid fibers, and cellulosic fibers. The flame-retardant fabrics of one or more embodiments of the present invention are substantially free of antimony compounds. As used herein, "substantially free of antimony compounds" means that antimony compounds are not intentionally added to fibers or fabrics as flame retardants, and refers to approximately 0% by mass. In one or more embodiments of the present invention, the char length of a fabric measured by a flammability test based on ASTM D6413 correlates with the tear strength of the fabric after combustion. Preferably, the fabric of one or more embodiments of the present invention has a char length of 75 mm or less measured by a flammability test based on ASTM D6413. Unless otherwise specified below, the char length refers to the value measured by a flammability test based on ASTM D6413.

[0010] In this specification, when a numerical range is indicated with "to", the numerical range includes both end values ​​(upper and lower limits). For example, a numerical range of "A to B" includes both end values ​​A and B, and is the same range as "A or more and B or less". Any number within that range and any range included within that range are specifically disclosed. In addition, when multiple numerical ranges are described in this specification, they are intended to include numerical ranges that combine the upper and lower limits of different numerical ranges as appropriate.

[0011] <Tin and Zinc-Containing Compound> The flame-retardant fabric of one or more embodiments of the present invention contains 1.4 to 5.0 mass% of a tin and zinc-containing compound. If the content of the tin and zinc-containing compound is less than 1.4 mass%, the tear strength after combustion decreases, the char length increases, and the flame retardancy deteriorates. On the other hand, if the content of the tin and zinc-containing compound exceeds 5.0 mass%, static electricity is likely to be generated when the fiber passes through a card, resulting in poor spinnability, which in turn reduces the productivity and processability of the fiber and fabric and increases costs. Furthermore, in a combustion test, the residual time increases and the flame retardancy deteriorates. From the viewpoint of increasing the tear strength after combustion and easily shortening the char length, the content of the tin and zinc-containing compound in the flame-retardant fabric is preferably 1.6 mass% or more, more preferably 1.8 mass% or more, even more preferably 2.0 mass% or more, and even more preferably 2.5 mass% or more. From the viewpoints of productivity, processability, and cost, the content of the tin- and zinc-containing compound in the flame-retardant fabric is preferably 4.9% by mass or less, more preferably 4.8% by mass or less, even more preferably 4.7% by mass or less, even more preferably 4.6% by mass or less, and particularly preferably 4.5% by mass or less. The tin- and zinc-containing compound may be attached to the surface of the flame-retardant fabric, but from the viewpoint of washing durability, it is preferable that it be contained inside the fibers that constitute the flame-retardant fabric. From the viewpoint of enhancing the flame-retardant effect of the tin- and zinc-containing compound, it is preferable that the tin- and zinc-containing compound be contained in modacrylic fibers. In one or more embodiments of the present invention, the content of the "tin- and zinc-containing compound" in the flame-retardant fabric can be measured by X-ray fluorescence analysis, specifically, as described in the examples.

[0012] The compound containing tin and zinc is not particularly limited, but from the viewpoint of versatility, for example, a zinc stannate compound can be used. The zinc stannate compound may be, for example, either zinc tin trioxide (ZnSnO) or zinc tin hexahydroxide (ZnSn(OH)), but from the viewpoint of further improving the flame retardancy of fibers, fabrics, and work clothes, zinc tin hexahydroxide is preferred.

[0013] The tin- and zinc-containing compound is not particularly limited, but from the viewpoint of, for example, spinnability and fiber strength, the average particle diameter D50 is preferably 3 μm or less, more preferably 2.5 μm or less, and even more preferably 2 μm or less. Furthermore, the lower limit of the average particle diameter D50 of the tin- and zinc-containing compound is not particularly limited, but from the viewpoint of, for example, handleability, it may be 0.1 μm or more, 0.5 μm or more, 0.6 μm or more, or 0.7 μm or more. In one or more embodiments of the present invention, the average particle diameter D50 of the compound is measured on a volume basis, and in the case of a powder, it can be measured by laser diffraction / scattering, and in the case of a dispersion (liquid) dispersed in water or an organic solvent, it can be measured by laser diffraction / scattering or dynamic light scattering.

[0014] <Modacrylic Fiber> The modacrylic fiber is not particularly limited as long as it is a fiber made from a modacrylic polymer, and any fiber containing a modacrylic polymer can be used as appropriate. The modacrylic fiber preferably contains a compound containing tin and zinc in addition to the modacrylic polymer, and more preferably contains a compound containing tin and zinc inside the fiber. By containing a compound containing tin and zinc inside the fiber, washing durability is improved, and the high flame retardancy effect of the compound containing tin and zinc as a flame retardant can be exhibited even after repeated washing.

[0015] From the viewpoint of enhancing the flame retardancy of the fabric, the modacrylic fiber preferably contains 2.4% by mass or more of the tin- and zinc-containing compound, more preferably 2.5% by mass or more, even more preferably 2.8% by mass or more, even more preferably 3.0% by mass or more, even more preferably 3.5% by mass or more, and particularly preferably 3.7% by mass or more. From the viewpoints of fiber productivity, processability, fiber physical properties, and the like, the modacrylic fiber preferably contains 10.4% by mass or less of the tin- and zinc-containing compound, more preferably 10.2% by mass or less, even more preferably 10.0% by mass or less, even more preferably 9.8% by mass or less, even more preferably 9.6% by mass or less, even more preferably 9.4% by mass or less, and particularly preferably 9.2% by mass or less. In one or more embodiments of the present invention, the content of the "tin- and zinc-containing compound" in the modacrylic fiber can be measured by X-ray fluorescence analysis, specifically as described in the examples.

[0016] From the viewpoint of enhancing the flame retardancy of the fabric, the modacrylic fiber preferably contains 89.6 to 97.6 mass% of a modacrylic polymer and 2.4 to 10.4 mass% of a compound containing tin and zinc, more preferably 89.8 to 97.5 mass% of a modacrylic polymer and 2.5 to 10.2 mass% of a compound containing tin and zinc, still more preferably 90.0 to 97.2 mass% of a modacrylic polymer and 2.8 to 10.0 mass% of a compound containing tin and zinc, and even more preferably 90.2 to 97.0 mass% of a modacrylic polymer. and 3.0 to 9.8 mass% of a compound containing tin and zinc, even more preferably 90.4 to 96.5 mass% of a modacrylic polymer and 3.5 to 9.6 mass% of a compound containing tin and zinc, even more preferably 90.6 to 96.3 mass% of a modacrylic polymer and 3.7 to 9.4 mass% of a compound containing tin and zinc, and particularly preferably 90.8 to 96.3 mass% of a modacrylic polymer and 3.7 to 9.2 mass% of a compound containing tin and zinc. Alternatively, from the viewpoint of improving the flame retardancy of the fabric, the modacrylic fiber preferably contains 2.5 parts by mass or more of a compound containing tin and zinc per 100 parts by mass of the modacrylic polymer, more preferably 3.0 parts by mass or more, even more preferably 3.2 parts by mass or more, even more preferably 3.8 parts by mass or more, and particularly preferably 4.0 parts by mass or more. From the viewpoints of fiber productivity, processability, fiber properties, and the like, the modacrylic fiber preferably contains 11.0 parts by mass or less of a compound containing tin and zinc, more preferably 10.5 parts by mass or less, even more preferably 10.0 parts by mass or less, even more preferably 9.8 parts by mass or less, even more preferably 9.6 parts by mass or less, even more preferably 9.4 parts by mass or less, and particularly preferably 9.2 parts by mass or less.

[0017] The modacrylic polymer preferably contains 40 to 70% by mass of acrylonitrile and 30 to 60% by mass of other components. If the content of acrylonitrile in the modacrylic polymer is 40 to 70% by mass, the heat resistance and flame retardancy of the modacrylic fiber will be good.

[0018] The other components are not particularly limited as long as they are copolymerizable with acrylonitrile, and examples thereof include halogen-containing monomers and sulfonic acid group-containing monomers.

[0019] Examples of halogen-containing monomers include halogen-containing vinyls and halogen-containing vinylidenes. Examples of halogen-containing vinyls include vinyl chloride and vinyl bromide, and examples of halogen-containing vinylidenes include vinylidene chloride and vinylidene bromide. These halogen-containing monomers may be used alone or in combination of two or more. From the viewpoints of heat resistance and flame retardancy, the modacrylic polymer preferably contains 30 to 60 mass % of a halogen-containing monomer as another component.

[0020] Examples of sulfonic acid group-containing monomers include methacrylic acid, allyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and salts thereof. Examples of salts include, but are not limited to, sodium salts, potassium salts, and ammonium salts. These sulfonic acid group-containing monomers may be used alone or in combination of two or more. Sulfonic acid group-containing monomers can be used as needed, for example, to enhance dyeability. If the content of sulfonic acid group-containing monomers in the modacrylic polymer is 3% by mass or less, excellent production stability in the spinning process is achieved. The modacrylic polymer may contain, for example, 0.5 to 3% by mass of sulfonic acid group-containing monomers.

[0021] The modacrylic polymer preferably contains 40 to 70% by mass of acrylonitrile, 30 to 57% by mass of a halogen-containing monomer, and 0 to 3% by mass of a sulfonic acid group-containing monomer, and more preferably contains 45 to 65% by mass of acrylonitrile, 35 to 52% by mass of a halogen-containing monomer, and 0 to 3% by mass of a sulfonic acid group-containing monomer. From the viewpoint of further improving handleability and flame retardancy, the halogen-containing monomer is preferably vinyl chloride and / or vinylidene chloride, and more preferably vinylidene chloride.

[0022] From the viewpoint of dyeability, the modacrylic polymer preferably contains 40 to 69.5% by mass of acrylonitrile, 30 to 57% by mass of a halogen-containing monomer, and 0.5 to 3% by mass of a sulfonic acid group-containing monomer, and more preferably contains 45 to 64.5% by mass of acrylonitrile, 35 to 52% by mass of a halogen-containing monomer, and 0.5 to 3% by mass of a sulfonic acid group-containing monomer. From the viewpoint of further improving handleability and flame retardancy, the halogen-containing monomer is preferably vinyl chloride and / or vinylidene chloride, and more preferably vinylidene chloride.

[0023] The modacrylic polymer can be obtained by known polymerization methods such as bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, etc. Among these, suspension polymerization, emulsion polymerization, and solution polymerization are preferred from an industrial viewpoint.

[0024] The modacrylic fiber may contain various additives, such as flame retardant aids, matting agents, crystal nucleating agents, dispersants, lubricants, stabilizers, fluorescent agents, antioxidants, antistatic agents, and pigments, as needed, within a range that does not impair the effects of the present invention. The content of additives other than the tin- and zinc-containing compounds in the modacrylic fiber may be, for example, 5% by mass or less, 3% by mass or less, or 1% by mass or less, within a range that does not impair the effects of the present invention. Alternatively, the content of additives other than the tin- and zinc-containing compounds in the modacrylic fiber may be, for example, 5 parts by mass or less, 3 parts by mass or less, or 1 part by mass or less, per 100 parts by mass of the modacrylic polymer, within a range that does not impair the effects of the present invention.

[0025] The single fiber fineness of the modacrylic fiber is not particularly limited, but from the viewpoints of spinnability, processability, and the texture and strength of woven and / or knitted fabrics, it is preferably 1 to 20 dtex, more preferably 1.5 to 15 dtex. The fiber length of the modacrylic fiber is not particularly limited, but from the viewpoints of spinnability and processability, it is preferably 38 to 127 mm, more preferably 38 to 76 mm. In this specification, the single fiber fineness of the fiber can be measured in accordance with JIS L 1015:2021.

[0026] The strength of the modacrylic fiber is not particularly limited, but from the viewpoint of spinnability and processability, it is preferably 1.0 to 4.0 cN / dtex, and more preferably 1.5 to 3.0 cN / dtex. The elongation of the modacrylic fiber is also not particularly limited, but from the viewpoint of spinnability and processability, it is preferably 20 to 35%, and more preferably 20 to 25%. In this specification, the strength and elongation of the fiber can be measured in accordance with JIS L 1015:2021.

[0027] Modacrylic fibers containing a compound containing tin and zinc within the fiber can be produced by wet-spinning the spinning dope in the same manner as for general modacrylic fibers, except that a compound containing tin and zinc, and, if necessary, other additives, are added to a spinning dope in which a modacrylic polymer is dissolved. From the viewpoints of, for example, the flame retardancy, productivity, processability, and fiber properties of the modacrylic fiber, the spinning dope preferably contains 2.5 to 11.0 parts by mass, more preferably 3.0 to 10.5 parts by mass, even more preferably 3.2 to 10.0 parts by mass, even more preferably 3.8 to 9.8 parts by mass, and particularly preferably 4.0 to 9.6 parts by mass of the compound containing tin and zinc per 100 parts by mass of the modacrylic polymer. The spinning dope may contain additives other than the tin- and zinc-containing compounds in an amount of, for example, 5 parts by mass or less, 3 parts by mass or less, or 1 part by mass or less per 100 parts by mass of the modacrylic polymer, as long as the effects of the present invention are not impaired.

[0028] The modacrylic fiber is preferably a solution-colored fiber. This eliminates the need for dyeing the fabric, reducing environmental impact and fabric costs. Solution-colored fibers can be obtained by adding a tin- and zinc-containing compound and a colorant to a spinning solution and then spinning the resulting spinning solution. Examples of colorants include organic pigments, inorganic pigments, and dyes.

[0029] <Cellulosic Fibers> Cellulosic fibers are a general term for fibers derived from cellulose, and may be natural cellulose fibers, semi-synthetic cellulose fibers, or regenerated cellulose fibers. Examples of natural cellulose fibers include cotton, hemp (including flax, ramie, jute, kenaf, hemp, Manila hemp, sisal, and New Zealand hemp), kapok, banana, and palm. Examples of semi-synthetic cellulose fibers include acetate and triacetate. Examples of regenerated cellulose fibers include rayon, cupra, and lyocell. These cellulose fibers may be used alone or in combination of two or more.

[0030] The cellulosic fibers may include, for example, a flame retardant, such as a compound containing tin or zinc, but preferably a phosphorus-based flame retardant.

[0031] From the viewpoint of texture and strength, for example, the cellulose-based fiber preferably includes one or more selected from the group consisting of natural cellulose fibers and regenerated cellulose fibers, more preferably includes one or more selected from the group consisting of lyocell, flame-retardant lyocell, rayon, and flame-retardant rayon, and even more preferably includes lyocell.

[0032] The flame-retardant lyocell preferably contains a phosphorus-based flame retardant. The phosphorus-based flame retardant is not particularly limited, and examples thereof include phosphate ester compounds, halogen phosphate ester compounds, condensed phosphate ester compounds, polyphosphate compounds, and polyphosphate ester compounds. The flame-retardant lyocell is not particularly limited, but from the viewpoint of, for example, enhancing flame retardancy, it preferably contains 0.5% by mass or more, and more preferably 0.8% by mass or more, of phosphorus derived from the phosphorus-based flame retardant. On the other hand, from the viewpoint of, for example, fiber strength, the flame-retardant lyocell preferably contains 10% by mass or less of phosphorus derived from the phosphorus-based flame retardant.

[0033] The flame-retardant rayon preferably contains a phosphorus-based flame retardant. The phosphorus-based flame retardant is not particularly limited, and examples thereof include phosphate ester compounds, halogen phosphate ester compounds, condensed phosphate ester compounds, polyphosphate compounds, and polyphosphate ester compounds. The flame-retardant rayon fiber is not particularly limited, but from the viewpoint of, for example, enhancing flame retardancy, it preferably contains 0.5% by mass or more, and more preferably 0.8% by mass or more, of phosphorus derived from the phosphorus-based flame retardant. On the other hand, from the viewpoint of, for example, fiber strength, it is preferable that the flame-retardant rayon fiber contains 10% by mass or less of phosphorus derived from the phosphorus-based flame retardant. In this specification, the phosphorus content in the fiber can be measured by X-ray fluorescence analysis.

[0034] The single fiber fineness of the cellulose-based fiber is not particularly limited, but from the viewpoint of strength, it is preferably 1 to 20 dtex, more preferably 1.5 to 15 dtex. The fiber length of the cellulose-based fiber is not particularly limited, but from the viewpoint of strength, it is preferably 38 to 127 mm, more preferably 38 to 76 mm.

[0035] <Aramid Fiber> The aramid fiber may be a para-aramid fiber or a meta-aramid fiber. The single fiber fineness of the aramid fiber is not particularly limited, but from the viewpoint of strength, it is preferably 1 to 20 dtex, more preferably 1.5 to 15 dtex. The fiber length of the aramid fiber is not particularly limited, but from the viewpoint of strength, it is preferably 38 to 127 mm, more preferably 38 to 76 mm.

[0036] <Flame-Retardant Fabric> In one or more embodiments of the present invention, the flame-retardant fabric contains 30 to 60% by mass of modacrylic fiber, 20 to 50% by mass of cellulosic fiber, and 10 to 20% by mass of aramid fiber. It preferably contains 35 to 55% by mass of modacrylic fiber, 25 to 50% by mass of cellulosic fiber, and 10 to 18% by mass of aramid fiber, and more preferably 38 to 53% by mass of modacrylic fiber, 30 to 50% by mass of cellulosic fiber, and 10 to 18% by mass of aramid fiber. A low modacrylic fiber content results in poor flame retardancy. A high modacrylic fiber content (containing a compound containing tin and zinc) tends to generate static electricity during carding, resulting in poor spinnability and therefore poor productivity and processability of the fabric. A low cellulosic fiber content results in poor texture. If the content of aramid fibers is low, the tear strength and flame retardancy will be poor. The flame-retardant fabric may contain 1.4 to 5.0 mass% of the compound containing tin and zinc, and more preferably 1.6 to 4.9 mass%, 1.8 to 4.8 mass%, 2.0 to 4.7 mass%, or 2.5 to 4.5 mass%.

[0037] From the viewpoint of further improving flame retardancy, texture, cost, and durability, the flame-retardant fabric of one or more preferred embodiments of the present invention preferably contains 30 to 60 mass% modacrylic fiber, 20 to 50 mass% of one or more regenerated cellulose fibers selected from the group consisting of lyocell, flame-retardant lyocell, rayon, and flame-retardant rayon, and 10 to 20 mass% para-aramid fiber; preferably contains 35 to 55 mass% modacrylic fiber, 25 to 50 mass% of one or more regenerated cellulose fibers selected from the group consisting of lyocell, flame-retardant lyocell, rayon, and flame-retardant rayon, and 10 to 18 mass% para-aramid fiber; and more preferably contains 38 to 53 mass% modacrylic fiber, 30 to 50 mass% of one or more regenerated cellulose fibers selected from the group consisting of lyocell, flame-retardant lyocell, rayon, and flame-retardant rayon, and 10 to 18 mass% para-aramid fiber. In this embodiment, the modacrylic fiber preferably contains 2.4 to 10.4 mass %, 2.5 to 10.2 mass %, 2.8 to 10.0 mass %, 3.0 to 10.0 mass %, 3.5 to 9.8 mass %, 3.5 to 9.6 mass %, 3.5 to 9.4 mass %, or 3.5 to 9.2 mass % of the compound containing tin and zinc.

[0038] From the viewpoint of further improving flame retardancy, texture, cost, and durability, the flame-retardant fabric of one or more preferred embodiments of the present invention preferably contains 30 to 60 mass% of modacrylic fiber, 20 to 50 mass% of lyocell, and 10 to 20 mass% of para-aramid fiber, more preferably 35 to 55 mass% of modacrylic fiber, 25 to 50 mass% of lyocell, and 10 to 18 mass% of para-aramid fiber, and even more preferably 38 to 53 mass% of modacrylic fiber, 30 to 50 mass% of lyocell, and 10 to 18 mass% of para-aramid fiber. In this embodiment, the modacrylic fiber preferably contains 2.4 to 10.4 mass %, 2.5 to 10.2 mass %, 2.8 to 10.0 mass %, 3.0 to 10.0 mass %, 3.5 to 9.8 mass %, 3.5 to 9.6 mass %, 3.5 to 9.4 mass %, or 3.5 to 9.2 mass % of the compound containing tin and zinc.

[0039] In one or more embodiments of the present invention, the flame-retardant fabric may contain other fibers in addition to modacrylic fibers, cellulosic fibers, and aramid fibers, as long as the purpose and effects of the present invention are not impaired. Examples of other fibers include conductive fibers, heat-resistant fibers, and high-strength, high-modulus fibers. For example, conductive fibers include metal fibers, metal-plated fibers, copper compound-coated fibers, and conductive-material-added fibers. Heat-resistant fibers include polyoxadiazole fibers, polyimide fibers, and polyamide-imide fibers. High-strength, high-modulus fibers include nylon fibers, polyester fibers, and polyarylate fibers. The flame-retardant fabric may contain 10% by mass or less, 8% by mass or less, or 1% by mass or less of other fibers based on the entire fabric.

[0040] The single fiber fineness of the other fibers is not particularly limited, but from the viewpoint of strength, it is preferably 1 to 20 dtex, more preferably 1.5 to 15 dtex. The fiber length of the other fibers is not particularly limited, but from the viewpoint of strength, it is preferably 38 to 127 mm, more preferably 38 to 76 mm.

[0041] The form of the flame-retardant fabric is not particularly limited, and examples thereof include woven fabrics and knitted fabrics. The weave of the woven fabric is not particularly limited, and may be a tri-weave such as plain weave, twill weave, or satin weave, or may be a patterned fabric woven using a special loom such as a dobby or jaguar weave. The weave of the knitted fabric is also not particularly limited, and may be any of circular knitting, flat knitting, and warp knitting. From the viewpoint of excellent durability, the flame-retardant fabric is preferably a woven fabric, and more preferably a twill weave.

[0042] The flame-retardant fabric is not particularly limited, but from the viewpoint of texture and flame retardancy, it is preferable that the fabric has a basis weight of 200 to 400 g / m 2 is preferable, and more preferably 220 to 380 g / m 2 and more preferably 250 to 350 g / m 2 is.

[0043] In one or more embodiments of the present invention, the flame-retardant fabric has excellent flame retardancy, and the char length measured by a flammability test based on ASTM D 6413 is preferably 75 mm or less, more preferably 73 mm or less, and even more preferably 71 mm or less. When the char length of the flame-retardant fabric differs in the two directions, the warp direction and the weft direction, the maximum value is preferably 75 mm or less, more preferably 73 mm or less, and even more preferably 71 mm or less.

[0044] In one or more embodiments of the present invention, the flame-retardant fabric has excellent flame retardancy, and the flame-retardant time measured by a flammability test based on ASTM D 6413 is preferably 10.0 seconds or less, more preferably 9.5 seconds or less, and even more preferably 9.0 seconds or less. When the flame-retardant time of the flame-retardant fabric differs in the two directions, the warp and weft directions, the maximum value is preferably 10.0 seconds or less, more preferably 9.5 seconds or less, and even more preferably 9.0 seconds or less.

[0045] <Workwear> In one or more embodiments of the present invention, the flame-retardant fabric can be suitably used for workwear requiring flame retardancy. In one or more embodiments of the present invention, the workwear can be manufactured using the flame-retardant fabric of one or more embodiments of the present invention by a known sewing method. In one or more embodiments of the present invention, since the flame-retardant fabric has excellent flame retardancy, the workwear also has excellent flame retardancy. Furthermore, since the flame-retardant fabric maintains an excellent texture even after repeated washing, the workwear maintains its flame retardancy and texture even after repeated washing. In one or more embodiments of the present invention, the workwear can be used as workwear for any work requiring flame retardancy. For example, but not limited to, the workwear can be used as protective clothing (firefighting clothing) worn by firefighters, protective clothing worn at work sites where fires may occur, such as oil, petrochemical, coal mining, power, and welding, and workwear worn at work sites where dust explosions are expected, such as metal processing.

[0046] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0047] The measurement and evaluation methods used in the examples and comparative examples are as follows.

[0048] (Static electricity when passing through card) In the carding process of fabric production, the amount of static electricity generated when passing through the card was measured using a static electricity meter (manufactured by Simco Japan Co., Ltd., model number "FMX-003"), and the spinning properties were evaluated according to the following criteria: Good: The amount of static electricity generated when passing through the card was in the range of -0.5 to +0.5 kV. Poor: The amount of static electricity generated when passing through the card was less than -0.5 kV or more than +0.5 kV.

[0049] <Flame Retardance> Evaluation was performed using a combustion test method based on ASTM D6413-99. The char length of a fabric is defined as the distance from the edge of the fabric directly exposed to flame under the test conditions of ASTM D6413-99 to the furthest point of visible damage to the fabric after applying a specified tear force. The char length of a fabric was measured in accordance with ASTM D6413-99 "Standard Test Method for Flame Resistance of Textiles (Vertical Method)." The char length is an index of the flame retardance of a textile material; the shorter the char length, the better the flame retardance. In addition, the char length correlates with the tear strength after the combustion test; the higher the tear strength after the combustion test, the shorter the char length. Furthermore, the remaining time of the fabric after contact with flame was determined according to the test conditions of ASTM D6413-99.

[0050] <Flame Retardant Content> The content of flame retardants (compounds containing tin and zinc) in modacrylic fibers or fabrics was measured by X-ray fluorescence analysis using an X-ray fluorescence analyzer ("SEA2210A" manufactured by SII Nanotechnology). The X-ray fluorescence intensity of tin was measured in advance using a standard sample with a known tin content, and a calibration curve was created. Next, the X-ray fluorescence intensity of tin in the modacrylic fibers was measured, and the tin content in the modacrylic fibers was measured by comparing it with the calibration curve. Next, the content of compounds containing tin and zinc in the modacrylic fibers or fabrics was calculated based on the tin content.

[0051] <Production Example 1> A modacrylic polymer consisting of 51% by mass of acrylonitrile, 48% by mass of vinylidene chloride, and 1% by mass of sodium p-styrenesulfonate was dissolved in dimethyl sulfoxide to a modacrylic polymer concentration of 30% by mass. To the resulting modacrylic polymer solution, 4 parts by mass of antimony trioxide (SbO, manufactured by Nippon Seiko Co., Ltd., product name "PATOX-M") was added per 100 parts by mass of the modacrylic polymer to prepare a spinning dope. The antimony trioxide was added in advance to a concentration of 30% by mass relative to dimethyl sulfoxide, and the antimony trioxide was uniformly dispersed and used as a dispersion. The average particle diameter D50 of the antimony trioxide dispersion measured by laser diffraction / scattering was 1.0 μm. The obtained spinning dope was extruded into a 50% by mass aqueous solution of dimethyl sulfoxide using a nozzle with a nozzle hole diameter of 0.08 mm and 300 holes to coagulate, then washed with water and dried at 120°C. After drying, the fiber was stretched to 3 times its original size and then heat-treated at 145°C for 5 minutes to obtain a modacrylic fiber. The obtained modacrylic fiber of Production Example 1 had a single fiber fineness of 1.7 dtex and a cut length of 51 mm.

[0052] <Production Example 2> A modacrylic fiber was produced in the same manner as in Production Example 1, except that the amount of antimony trioxide added was 8 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 2 had a single fiber fineness of 1.6 dtex and a cut length of 51 mm.

[0053] Production Example 3 A modacrylic fiber was produced in the same manner as in Production Example 1, except that the amount of antimony trioxide added was 9 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 3 had a single fiber fineness of 1.7 dtex and a cut length of 51 mm.

[0054] Production Example 4 Modacrylic fiber was produced in the same manner as in Production Example 1, except that zinc tin hexahydroxide (ZnSn(OH)6, manufactured by SCL Italia. Spa, product name "Zinflam (registered trademark) ZHS") was used instead of antimony trioxide and the amount of zinc tin hexahydroxide added was 2 parts by mass per 100 parts by mass of the modacrylic polymer. In the dispersion of zinc tin hexahydroxide, the average particle diameter D50 of the zinc tin hexahydroxide measured by laser diffraction / scattering method was 1.2 μm. The obtained modacrylic fiber of Production Example 4 had a single fiber fineness of 1.7 dtex and a cut length of 51 mm.

[0055] Production Example 5 A modacrylic fiber was produced in the same manner as in Production Example 4, except that the amount of zinc tin hexahydroxide added was 4 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 5 had a single fiber fineness of 1.6 dtex and a cut length of 51 mm.

[0056] Production Example 6 A modacrylic fiber was produced in the same manner as in Production Example 4, except that the amount of zinc tin hexahydroxide added was 6 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 6 had a single fiber fineness of 2.0 dtex and a cut length of 51 mm.

[0057] Production Example 7 A modacrylic fiber was produced in the same manner as in Production Example 4, except that the amount of zinc tin hexahydroxide added was 7 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 7 had a single fiber fineness of 1.7 dtex and a cut length of 51 mm.

[0058] Production Example 8 A modacrylic fiber was produced in the same manner as in Production Example 4, except that the amount of zinc tin hexahydroxide added was 8 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 8 had a single fiber fineness of 1.7 dtex and a cut length of 51 mm.

[0059] Production Example 9 A modacrylic fiber was produced in the same manner as in Production Example 4, except that the amount of zinc tin hexahydroxide added was 9 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 9 had a single fiber fineness of 1.8 dtex and a cut length of 51 mm.

[0060] Production Example 10 A modacrylic fiber was produced in the same manner as in Production Example 4, except that the amount of zinc tin hexahydroxide added was 10 parts by mass per 100 parts by mass of the modacrylic polymer. The obtained modacrylic fiber of Production Example 10 had a single fiber fineness of 1.8 dtex and a cut length of 51 mm.

[0061] <Production Example 11> Stannic oxide (SnO, manufactured by Showa Kako Co., Ltd.) was used instead of antimony trioxide, and zinc borate (ZnBO 11 Modacrylic fiber was produced in the same manner as in Production Example 1, except that 4 parts by mass of stannic oxide and 3.5H2O (manufactured by Sakai Chemical Industry Co., Ltd.) were added in amounts of 4 parts by mass per 100 parts by mass of modacrylic polymer, for a total amount of 8 parts by mass. In the stannic oxide dispersion, the average particle diameter D50 of stannic oxide measured by laser diffraction / scattering was 1.7 μm, and in the zinc borate dispersion, the average particle diameter D50 of zinc borate measured by laser diffraction / scattering was 1.5 μm. The obtained modacrylic fiber of Production Example 11 had a single fiber fineness of 1.9 dtex and a cut length of 51 mm.

[0062] The types and contents of the flame retardants in the modacrylic fibers of Production Examples 1 to 11 are shown in Table 1 below.

[0063]

[0064] Examples 1 to 8, Comparative Examples 1 to 8 The modacrylic fibers of Production Examples 1 to 11, lyocell ("Tencel (registered trademark)" manufactured by Lenzing, single fiber fineness 1.3 dtex, fiber length 51 mm), and para-aramid fiber ("Taparan" manufactured by Yantai Taiho New Materials Co., Ltd., fineness 1.7 dtex, fiber length 51 mm) were blended in the predetermined mass ratios shown in Table 2 below, and the blend was defibrated using a sample roller card SC-500 manufactured by Yamato Kiko Co., Ltd., and a sliver was produced using a small continuous yarn spinning machine TSM-DFS manufactured by Intec Corporation. Next, using this sliver, a roving yarn was produced using a high-speed roving frame FL200 manufactured by Toyota Industries Corporation, and a ring-spun yarn with a count of 12.5 / 1 to 13.5 / 1 was produced using a high-speed spinning frame UA37 manufactured by Howa Kogyo Co., Ltd. A 2 / 1 twill fabric was produced using this spun yarn. The number of threads and basis weight were as shown in Table 2 below.

[0065] The flame retardancy of the fabrics obtained in Examples 1 to 8 and Comparative Examples 1 to 8 was measured as described above, and the results are shown in Table 2 below. Table 2 below also shows the content of the flame retardant in the fabric.

[0066]

[0067] As can be seen from Table 2, the fabrics of the Examples had a maximum char length of 75 mm or less, as evaluated by the combustion test method based on ASTM D6413-99, and exhibited extremely good flame retardancy (char film strength). Furthermore, in Examples 4 and 8, almost no static electricity was generated when the fabric passed through a card, and the fabrics exhibited good productivity and processability. Examples 1 to 3, which had the same fiber composition as Example 4 but used modacrylic fibers with a lower zinc tin hexahydroxide content than the modacrylic fiber used in Example 4, generated almost no static electricity when the fabric passed through a card, similar to Example 4, and are presumed to have good productivity and processability. Examples 5 to 7, which had the same fiber composition as Example 8 but used modacrylic fibers with a lower zinc tin hexahydroxide content than the modacrylic fiber used in Example 8, generated almost no static electricity when the fabric passed through a card, similar to Example 8, and are presumed to have good productivity and processability. Furthermore, the fabrics of the examples had a flame retardancy of 10 seconds or less as evaluated by the combustion test method based on ASTM D6413-99, and the flame retardancy as measured by the flame retardancy was also good.

[0068] On the other hand, the fabric of Comparative Example 3, which uses modacrylic fiber to which zinc tin hexahydroxide has been added as a flame retardant as in Examples 1 to 8, but in which the amount of zinc tin hexahydroxide added is less than 1.4 mass%, has a maximum char length of more than 75 mm as evaluated by the combustion test method based on ASTM D6413-99, and is therefore inferior in flame retardancy.

[0069] The amount of flame retardant in the modacrylic fiber and the blending ratios of the modacrylic fiber, cellulosic fiber, and aramid fiber were the same as in Example 1, but the fabric of Comparative Example 1, which used antimony trioxide as the flame retardant, had a longer char length evaluated by the combustion test method based on ASTM D6413-99 and was therefore inferior in flame retardancy compared to the fabric of Example 1. Similarly, the amount of flame retardant in the modacrylic fiber and the blending ratios of the modacrylic fiber, cellulosic fiber, and aramid fiber were the same as in Examples 3 and 8, respectively, but the fabrics of Comparative Examples 2 and 4, which used antimony trioxide as the flame retardant, had a longer char length evaluated by the combustion test method based on ASTM D6413-99 and were therefore inferior in flame retardancy compared to the fabrics of Examples 3 and 8, respectively. In the case of the fabric of Comparative Example 5, which uses the modacrylic fiber of Production Example 11, to which a combination of tin oxide and zinc borate was added as a flame retardant, the flame could not be extinguished when evaluated for flame retardancy using the combustion test method based on ASTM D6413-99, and the flame was poor. In the case of the fabric of Comparative Example 6, which has a low modacrylic fiber content, the flame could not be extinguished when evaluated for flame retardancy using the combustion test method based on ASTM D6413-99, and the flame was poor. In the cases of Comparative Example 7, which has a high content of modacrylic fiber containing zinc tin hexahydroxide, and Comparative Example 8, which has a high amount of zinc tin hexahydroxide, static electricity was high when the fabric was passed through a card, and the productivity and processability of the fabric were poor. Furthermore, in the cases of Comparative Example 7, which has a high content of modacrylic fiber, and Comparative Example 8, which has a high amount of zinc tin hexahydroxide, the dwell time evaluated using the combustion test method based on ASTM D6413-99 exceeded 10 seconds, and the flame was also poor.

[0070] The present invention is not particularly limited, but preferably includes the following embodiments. [1] A flame-retardant fabric containing 30 to 60 mass% of modacrylic fiber, 20 to 50 mass% of cellulosic fiber, and 10 to 20 mass% of aramid fiber, and containing 1.4 to 5.0 mass% of a compound containing tin and zinc relative to the total mass of the fabric. [2] The flame-retardant fabric according to [1], wherein the flame-retardant fabric has a char length of 75 mm or less as measured by a flammability test based on ASTM D6413. [3] The flame-retardant fabric according to [1] or [2], wherein the modacrylic fiber contains the compound containing tin and zinc. [4] The flame-retardant fabric according to [3], wherein the modacrylic fiber contains 2.4 to 10.4 mass% of the compound containing tin and zinc. [5] The flame-retardant fabric according to any one of [1] to [4], wherein the compound containing tin and zinc comprises at least one selected from the group consisting of zinc tin hexahydroxide and zinc tin trioxide. [6] The flame-retardant fabric according to any one of [1] to [5], wherein the cellulosic fiber comprises at least one selected from the group consisting of natural cellulose fiber and regenerated cellulose fiber. [7] The flame-retardant fabric according to any one of [1] to [6], wherein the cellulosic fiber comprises at least one selected from the group consisting of lyocell, flame-retardant lyocell, rayon, and flame-retardant rayon. [8] The flame-retardant fabric according to any one of [1] to [7], wherein the cellulosic fiber comprises lyocell. [9] The flame-retardant fabric according to any one of [1] to [8], wherein the aramid fiber is a para-aramid fiber.

[10] The flame-retardant fabric according to any one of [1] to [9], wherein the modacrylic fiber is a solution-dyed fiber.

[11] The flame-retardant fabric according to any one of [1] to

[10] , wherein the flame-retardant fabric has a dwell time of 10 seconds or less as measured by a flammability test based on ASTM D6413.

[12] Work clothes using the flame-retardant fabric according to any one of [1] to

[11] .

Claims

1. The fabric contains 30 to 60% by mass of modacrylic fiber, 20 to 50% by mass of cellulosic fiber, and 10 to 20% by mass of aramid fiber, and contains 1.4 to 5.0% by mass of a compound containing tin and zinc relative to the total mass of the fabric, Substantially free of antimony compounds; A flame-retardant fabric having a char length of 71 mm or less as measured by a flammability test based on ASTM D6413.

2. The flame-retardant fabric of claim 1, which is formed from spun yarn, the spun yarn containing 30 to 60 mass% modacrylic fiber, 20 to 50 mass% cellulosic fiber, and 10 to 20 mass% aramid fiber.

3. The flame-retardant fabric of claim 1, wherein the flame-retardant fabric is formed from spun yarn, the spun yarn containing 40 to 48 mass% modacrylic fiber, 37 to 48 mass% cellulosic fiber, and 12 to 15 mass% aramid fiber.

4. 2. The flame retardant fabric of claim 1, wherein said modacrylic fiber contains said tin and zinc containing compound.

5. The flame retardant fabric according to claim 4, wherein the modacrylic fiber contains 2.4 to 10.4 mass% of the compound containing tin and zinc.

6. 2. The flame retardant fabric according to claim 1, wherein the compound containing tin and zinc comprises at least one selected from the group consisting of zinc tin hexahydroxide and zinc tin trioxide.

7. The flame-retardant fabric according to claim 1 , wherein the cellulosic fibers include at least one selected from the group consisting of natural cellulose fibers and regenerated cellulose fibers.

8. 2. The flame retardant fabric of claim 1, wherein the cellulosic fibers include one or more selected from the group consisting of lyocell, flame retardant lyocell, rayon, and flame retardant rayon.

9. 10. The flame retardant fabric of claim 1, wherein the cellulosic fibers comprise lyocell.

10. The flame retardant fabric of claim 1 , wherein the aramid fibers are para-aramid fibers.

11. 10. The flame retardant fabric of claim 1, wherein said modacrylic fibers are solution dyed fibers.

12. 2. The flame retardant fabric of claim 1, wherein the flame retardant fabric has a dwell time of 10 seconds or less as measured by a flammability test based on ASTM D6413.

13. Work clothes comprising the flame-retardant fabric according to any one of claims 1 to 12.