Flame-retardant fabric and flame-retardant work clothes comprising same

Abstract

The present invention pertains to a flame-retardant fabric comprising modified polyacrylonitrile fibers A, modified polyacrylonitrile fibers B, and cellulose-based fibers, the modified polyacrylonitrile fibers A containing a compound containing tin and zinc and substantially not containing a magnesium compound, the modified polyacrylonitrile fibers B containing a magnesium compound and substantially not containing a compound containing tin and zinc, and the cellulose-based fibers A containing a compound containing tin and zinc and substantially not containing a magnesium compound. The flame-retardant fabric contains 2.0 mass% or more of a tin and zinc-containing compound derived from the modified polyacrylonitrile fiber A. The thickness of a carbonized film of the flame-retardant fabric after a combustion test according to ISO15025 is 4.0 mm or more.

Description

Technical Field

[0001] The present invention relates to a flame-retardant fabric comprising modacrylic fiber and cellulosic fiber, and flame-retardant work clothes comprising the same. Background Art

[0002] The combination of halogen-containing fibers such as modified polyacrylonitrile fibers and other fibers such as cellulose fibers is generally particularly suitable for use in the field of work clothes. On the other hand, the flame retardancy of halogen-containing fibers such as modified polyacrylonitrile fibers has generally been a method of containing 1 to 50 parts by mass of antimony compounds as flame retardants (for example, Patent Document 1). However, antimony compounds may have an impact on the environment and the human body, so flame retardants other than antimony compounds are being studied. For example, in Patent Document 2, it is proposed to include a tin compound as a compound that imparts flame retardancy to halogen-containing fibers, and to use the halogen-containing fibers in combination with cellulose fibers.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 4-18050

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 10-001822 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, when a zinc stannate compound is used as a flame retardant, there is a problem in that the flame retardancy is inferior compared to the case of using an antimony compound.

[0009] The present invention aims to solve the above-mentioned conventional problems and provides a flame-retardant fabric having improved flame retardancy while taking environmental considerations into account, and a flame-retardant work garment including the flame-retardant fabric.

[0010] Means for solving problems

[0011] One or more embodiments of the present invention relate to a flame-retardant fabric comprising a modacrylic fiber A, a modacrylic fiber B, and a cellulosic fiber, wherein the modacrylic fiber A contains a compound containing tin and zinc and contains substantially no magnesium compound, and the modacrylic fiber B contains a magnesium compound and contains substantially no tin and zinc compound. The flame-retardant fabric contains 2% by mass or more of the tin and zinc compound derived from the modacrylic fiber A, and the flame-retardant fabric has a carbonized film thickness of 4.0 mm or more after a combustion test in accordance with ISO 15025.

[0012] One or more embodiments of the present invention relate to flame-retardant workwear comprising the flame-retardant fabric.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a flame-retardant fabric having improved flame retardancy while taking the environment into consideration, and a flame-retardant work garment including the flame-retardant fabric. DETAILED DESCRIPTION

[0015] The inventors of the present invention have conducted extensive research to improve the flame retardancy of fabrics comprising modacrylic fibers and cellulosic fibers, taking environmental considerations into account. As a result, they discovered that by including a modacrylic fiber A containing tin and zinc compounds and substantially free of magnesium compounds, a modacrylic fiber B containing a magnesium compound and substantially free of tin and zinc compounds, and a cellulosic fiber in the fabric, and by keeping the tin and zinc compounds in the fabric within a specified range, the fabric exhibits excellent flame retardancy (both gas-phase and solid-phase flame retardancy).

[0016] Particularly surprisingly, the inventors of the present invention have discovered that, when a modacrylic fiber containing a tin- and zinc-containing compound and a magnesium compound is used in combination with a cellulosic fiber, the flame retardancy is poor. However, by using the cellulosic fiber in combination with a modacrylic fiber A containing a tin- and zinc-containing compound and substantially free of magnesium, and a modacrylic fiber B containing a magnesium compound and substantially free of tin and zinc, the flame retardancy of the fabric is improved by utilizing the synergistic effect of the gas phase flame retardancy of the tin- and zinc-containing compound in the modacrylic fiber A and the solid phase flame retardancy of the magnesium compound in the modacrylic fiber B. The fabric exhibits extremely high flame retardancy in a combustion test used as a standard for evaluating the flame retardancy of workwear, such as the ISO 15025 combustion test method. Specifically, the fabric exhibits short afterflame and afterglow times, and forms a foamed carbonized film. When the thickness of the carbonized film of the flame-retardant fabric after the ISO 15025 combustion test is 4.0 mm or more, the carbonized film forms a barrier layer to prevent the flame from spreading to the back surface, thereby improving the protective properties of the work clothes using the flame-retardant fabric on the human body.

[0017] In this specification, when a numerical range is represented by "to", the numerical range includes both ends (upper and lower limits). For example, a numerical range such as "A to B" is a range that includes both ends of A and B, and is the same as "A or more and B or less". In addition, in this specification, when multiple numerical ranges are described, the numerical range includes a numerical range formed by appropriately combining the upper and lower limits of different numerical ranges.

[0018] (Flame retardant fabric)

[0019] The flame-retardant fabric according to one or more embodiments of the present invention contains 2.0% or more of a tin- and zinc-containing compound, preferably 2.2% or more, more preferably 2.4% or more, and even more preferably 2.6% or more. The tin- and zinc-containing compound in the flame-retardant fabric is derived from the modacrylic fiber A. By containing the tin- and zinc-containing compound within the above range, flame retardancy, particularly vapor-phase flame retardancy, is improved. The upper limit of the content of the tin- and zinc-containing compound in the flame-retardant fabric is not particularly limited. For example, from the perspective of spinnability of the modacrylic fiber A, the content is preferably 12% or less, more preferably 10% or less, even more preferably 8.0% or less, and particularly preferably 6.0% or less. More specifically, the flame-retardant fabric preferably contains 2.0 to 12% by mass, 2.2 to 10% by mass, 2.4 to 8.0% by mass, or 2.6 to 6.0% by mass of the tin- and zinc-containing compound.

[0020] Modacrylic fiber A contains compounds containing tin and zinc, but contains substantially no magnesium compounds. In this specification, the term "substantially contains no magnesium compounds" means that the fiber or fabric does not intentionally contain magnesium compounds. If magnesium compounds are present as impurities, the term "substantially contains no magnesium compounds" applies. By using such modacrylic fiber A in combination with modacrylic fiber B, a synergistic effect can be achieved, improving both gas-phase and solid-phase flame retardancy.

[0021] Modacrylic fiber A is not particularly limited. As long as the content of the tin- and zinc-containing compound in the flame-retardant fabric satisfies the above-mentioned range, fibers comprising a modacrylic polymer and a tin- and zinc-containing compound can be suitably used. From the perspective of flame retardancy durability after washing, the modacrylic fiber A preferably contains a tin- and zinc-containing compound within the fiber.

[0022] From the viewpoints of flame retardancy, spinnability, fiber strength, and cloth strength, the modacrylic fiber A preferably contains 5.5 to 25 parts by mass of the compound containing tin and zinc relative to 100 parts by mass of the modacrylic polymer, more preferably 6 to 20 parts by mass, even more preferably 7 to 18 parts by mass, and particularly preferably 8 to 16 parts by mass.

[0023] From the perspective of further improving gas-phase and solid-phase flame retardancy through flame retardancy, particularly through a synergistic effect with modacrylic fiber B, modacrylic fiber A preferably contains 5% by mass or more of tin- and zinc-containing compounds, more preferably 6% by mass or more, even more preferably 7% by mass or more, and particularly preferably 8% by mass or more. Furthermore, from the perspective of fiber strength and fabric strength, modacrylic fiber A preferably contains 20% by mass or less, more preferably 18% by mass or less, even more preferably 16% by mass or less, and particularly preferably 14% by mass or less of tin- and zinc-containing compounds. More specifically, modacrylic fiber A preferably contains 5-20% by mass, 6-18% by mass, 7-16% by mass, or 8-14% by mass of tin- and zinc-containing compounds. In this specification, the content of "tin- and zinc-containing compounds" in modacrylic fiber can be measured using fluorescent X-ray analysis.

[0024] The compound containing tin and zinc is not particularly limited. For example, zinc stannate compounds can be used from the perspective of versatility. The zinc stannate compound can be, for example, zinc tin trioxide (ZnSnO3) or zinc tin hexahydroxylate (ZnSn(OH)6). For example, zinc tin hexahydroxylate is preferably included from the perspective of further improving the flame retardancy of modacrylic fibers, fabrics, and workwear.

[0025] The above-mentioned compound containing tin and zinc is not particularly limited. For example, from the viewpoint of spinnability and fiber strength, the median particle size (D50) is preferably 3.0 μm or less, more preferably 2.5 μm or less, and further preferably 2.0 μm or less. In addition, the lower limit of the median particle size (D50) of the above-mentioned compound containing tin and zinc is not particularly limited. For example, from the viewpoint of handleability, it can be 0.1 μm or more, and from the viewpoint of flame retardancy, it can be 0.5 μm or more, 0.6 μm or more, or 0.7 μm or more. More specifically, the median particle size (D50) of the above-mentioned compound containing tin and zinc can be 0.1-3.0 μm, 0.5-2.5 μm, 0.6-2.0 μm or 0.7-2.0 μm. In this specification, the median particle size (D50) of the compound can be measured by a laser diffraction / scattering method or a dynamic light scattering method using a dispersion (dispersion liquid) dispersed in water or an organic solvent.

[0026] The modified polyacrylonitrile polymer may be a modified polyacrylonitrile polymer containing acrylonitrile, a halogen-containing monomer, and other copolymerizable monomers. The modified polyacrylonitrile polymer is not particularly limited. For example, from the perspective of further improving heat resistance and flame retardancy, it is preferably composed of 30 to 85% by mass of acrylonitrile, 15 to 70% by mass of a halogen-containing monomer, and 0 to 3% by mass or less of other copolymerizable monomers. It is more preferably composed of 35 to 75% by mass of acrylonitrile, 25 to 65% by mass of a halogen-containing monomer, and 0 to 3% by mass or less of other copolymerizable monomers. It is further preferably composed of 40 to 70% by mass of acrylonitrile, 30 to 60% by mass of a halogen-containing monomer, and 0 to 3% by mass or less of other copolymerizable monomers.

[0027] Examples of the halogen-containing monomer include halogen-containing vinyl monomers such as vinyl chloride and vinyl bromide, and halogen-containing vinylidene monomers such as vinylidene chloride and vinylidene bromide. One of these halogen-containing monomers may be used alone, or two or more may be used in combination. From the perspective of heat resistance, the halogen-containing monomer is preferably a halogen-containing vinylidene monomer, and vinylidene chloride is more preferred from the perspective of the synergistic effect of flame retardancy with compounds containing tin and zinc.

[0028] As above-mentioned other copolymerizable monomers, as long as can be the monomer that can be copolymerized with acrylonitrile, be not particularly limited, for example can use the unsaturated carboxylic acids and their salts of representatives, the methacrylic acid ester of representatives, the esters of the unsaturated carboxylic acids of representatives, the vinyl esters of representatives, the sulfonic acid containing monomers etc. with vinyl acetate, vinyl butyrate etc. as vinyl esters of representatives with vinyl sulfonic acid esters.As above-mentioned sulfonic acid containing monomers, be not particularly limited, for example can use metal salts and amine salts etc. such as allyl sulfonic acid, methallyl sulfonic acid, styrenesulfonic acid, isoprenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and their sodium salts.These other copolymerizable vinyl monomers can use 1 kind separately, also can be used in combination more than 2 kinds.Wherein, from the viewpoint that improves dyeability, can use the sulfonic acid containing monomers.

[0029] From the perspectives of flame retardancy, spinnability, fiber strength, and fabric strength, the modacrylic fiber A preferably comprises, for example, 80-95% by mass of the modacrylic polymer and 5-20% by mass of the tin- and zinc-containing compound. More preferably, it comprises 82-94% by mass of the modacrylic polymer and 6-18% by mass of the tin- and zinc-containing compound. Even more preferably, it comprises 83-93% by mass of the modacrylic polymer and 7-16% by mass of the tin- and zinc-containing compound. Even more preferably, it comprises 86-92% by mass of the modacrylic polymer and 8-14% by mass of the tin- and zinc-containing compound. Modacrylic fiber A may optionally contain other additives such as an antistatic agent, a heat discoloration inhibitor, a light fastness enhancer, a whiteness enhancer, a devitrification inhibitor, and a colorant. The content of these other additives in the modacrylic fiber A may be 10% or less, 5% or less, or 1% or less by mass.

[0030] Modified polyacrylonitrile fiber A can be any of short fibers and long fibers, and can be appropriately selected in the method of use. The single fiber fineness of modified polyacrylonitrile fiber A is appropriately selected according to the use of fabrics, work clothes, etc., and can be 1 to 50 dtex, 1.5 to 30 dtex, or 1.7 to 15 dtex. The fiber length of modified polyacrylonitrile fiber A is appropriately selected according to the use of fabrics, work clothes, etc. For example, short fibers (for example, fiber length 0.1 to 5 mm), short fibers (for example, fiber length 15 to 176 mm, 20 to 160 mm, 25 to 138 mm, or 30 to 128 mm), and long fibers (filaments) can be mentioned.

[0031] For example, from the perspective of durability, the single fiber strength of modacrylic fiber A is preferably 1.0 to 4.0 cN / dtex, more preferably 1.5 to 3.5 cN / dtex. For example, from the perspective of practicality, the elongation of modacrylic fiber A is preferably 15 to 40%, more preferably 20 to 30%. In this specification, the single fiber strength and elongation of fibers can be measured in accordance with JIS L 1013:2010 or JIS L 1015:2010.

[0032] The method for producing the modified polyacrylonitrile fiber A is not particularly limited, but it can preferably be produced by spinning a composition comprising the modified polyacrylonitrile polymer and the compound containing tin and zinc. Specifically, spinning can be performed by known methods such as wet spinning, dry spinning, and semi-wet / dry spinning. For example, in the case of wet spinning, a spinning solution comprising the modified polyacrylonitrile polymer, the compound containing tin and zinc, and a solvent is used. Similar to conventional modified polyacrylonitrile fibers, the spinning solution can be extruded through a nozzle into a coagulation bath to coagulate the solution, followed by stretching, washing, drying, and, if necessary, stretching and heat relaxation to produce the fibers. Furthermore, if desired, the fibers can be crimped and cut to a desired fiber length. The spinning solution can be produced by dissolving the modified polyacrylonitrile polymer in a solvent and then adding the compound containing tin and zinc thereto. Alternatively, the spinning solution can be produced by adding a dispersion of the compound containing tin and zinc in a solvent to a solution of the modified polyacrylonitrile polymer dissolved in a solvent. Examples of the solvent include organic solvents such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and acetone; and inorganic solvents such as aqueous thiocyanate solutions and aqueous nitric acid solutions.

[0033] The flame-retardant fabric according to one or more embodiments of the present invention contains a magnesium compound. The magnesium compound in the flame-retardant fabric is derived from the modacrylic fiber B, thereby improving the flame retardancy of the modacrylic fiber, particularly its solid-phase flame retardancy, and enabling the formation of a carbonized film having a thickness of 4 mm or greater in the ISO 15025 combustion test. To further improve flame retardancy, the flame-retardant fabric preferably contains 0.1% by mass or greater of the magnesium compound, more preferably 0.3% by mass or greater, and even more preferably 0.5% by mass or greater. The upper limit of the content of the magnesium compound in the flame-retardant fabric is not particularly limited. For example, from the perspective of spinnability of the modacrylic fiber B, the content is preferably 1.75% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.375% by mass or less. More specifically, the flame-retardant fabric preferably contains 0.1 to 1.75% by mass, 0.3 to 1.5% by mass, or 0.5 to 1.375% by mass of the magnesium compound.

[0034] Modacrylic fiber B contains a magnesium compound but contains substantially no tin- and zinc-containing compounds. In this specification, the phrase "substantially contains no tin- and zinc-containing compounds" means that the fiber or fabric does not intentionally contain tin- and zinc-containing compounds. If tin- and zinc-containing compounds are present as inclusions, the fiber or fabric is considered "substantially free of tin- and zinc-containing compounds." By using such modacrylic fiber B in combination with modacrylic fiber A, a synergistic effect is achieved, improving both gas-phase and solid-phase flame retardancy.

[0035] Regarding the modacrylic fiber B, any fiber containing a modacrylic polymer and a magnesium compound can be suitably used, as long as the flame-retardant fabric can form a carbonized film with a thickness of 4 mm or greater in the ISO 15025 combustion test. From the perspective of flame retardancy durability after washing, the modacrylic fiber B preferably contains a magnesium compound within the fiber.

[0036] From the perspective of further improving flame retardancy, modacrylic fiber B preferably contains 0.6 parts by mass or more of the magnesium compound per 100 parts by mass of the modacrylic polymer, more preferably 0.8 parts by mass or more, even more preferably 1.0 parts by mass or more, and particularly preferably 1.5 parts by mass or more. Furthermore, from the perspective of fiber strength and fabric strength, modacrylic fiber B preferably contains 6.5 parts by mass or less of the magnesium compound per 100 parts by mass of the modacrylic polymer, more preferably 6.0 parts by mass or less, even more preferably 5.5 parts by mass or less, and particularly preferably 5.0 parts by mass or less. More specifically, modacrylic fiber B preferably contains 0.6 to 6.5 parts by mass, 0.8 to 6.0 parts by mass, 1.0 to 5.5 parts by mass, or 1.5 to 5.5 parts by mass of the magnesium compound per 100 parts by mass of the modacrylic polymer.

[0037] From the perspective of further improving gas-phase and solid-phase flame retardancy through flame retardancy, particularly through a synergistic effect with modacrylic fiber A, modacrylic fiber B preferably contains 0.5% by mass or more, more preferably 0.8% by mass or more, even more preferably 1.2% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.8% by mass or more of a magnesium compound. Furthermore, from the perspective of fiber strength and fabric strength, modacrylic fiber B preferably contains 7% by mass or less of a magnesium compound, more preferably 6% by mass or less, and even more preferably 5.5% by mass or less. More specifically, modacrylic fiber B preferably contains 0.5-7% by mass, 0.8-6% by mass, 1.2-6% by mass, 1.5-5.5% by mass, or 1.8-5.5% by mass of a magnesium compound. In this specification, the content of "magnesium compound" in the modacrylic fiber can be measured by fluorescent X-ray analysis.

[0038] Examples of the magnesium compound include magnesium oxide, magnesium peroxide, magnesium hydroxide, magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, magnesium hydride, magnesium diboride, magnesium nitride, magnesium sulfide, magnesium carbonate, magnesium calcium carbonate, magnesium nitrate, magnesium sulfate, magnesium sulfite, magnesium perchlorate, trimagnesium phosphate, magnesium permanganate, and magnesium phosphate. Among these, magnesium oxide and magnesium hydroxide are preferably used from the perspective of ease of handling. Furthermore, magnesium hydroxide is preferably used from the perspective of Mohs hardness.

[0039] The magnesium hydroxide is not particularly limited, and examples thereof include: a powder obtained by crushing natural brucite ore, a powder obtained by neutralizing a magnesium salt aqueous solution with an alkali, a powder obtained by treating magnesium hydroxide particles with phosphates and borates, and a material obtained by slowly generating magnesium hydroxide by hydrating magnesium oxide. Furthermore, the magnesium hydroxide may be adsorbed by an adsorbable substance around the magnesium hydroxide particles, or may be coated by surface treatment. From the perspective of suppressing static electricity, magnesium hydroxide coated by surface treatment with a silane coupling agent is preferred. The reasons for improving static electricity suppression by surface treatment with a silane coupling agent are not definitive, but are believed to be as follows. It is believed that by silane coupling the surface of the magnesium hydroxide particles, the dispersibility of the silane-coupled magnesium hydroxide and the modified polyacrylonitrile fiber B containing the magnesium hydroxide is improved, resulting in static electricity suppression. Furthermore, if an oil is applied to the fiber surface to improve processability, the oil is fully exerted on the surface of the magnesium hydroxide particles, significantly improving processability. The type of silane coupling agent is not particularly limited as long as it improves compatibility with the modified polyacrylonitrile polymer described below, and is not particularly limited to crosslinking or non-crosslinking types.

[0040] The magnesium compound is not particularly limited. For example, from the perspectives of spinnability, fiber strength, and fabric strength, the median particle size (D50) is preferably 3.0 μm or less, more preferably 2.5 μm or less, and even more preferably 2.0 μm or less. The lower limit of the median particle size (D50) of the magnesium compound is not particularly limited. For example, from the perspective of 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. More specifically, the median particle size (D50) of the magnesium compound may be 0.1 to 3.0 μm, 0.5 to 2.5 μm, 0.6 to 2.0 μm, or 0.7 to 2.0 μm.

[0041] In the modacrylic fiber B, the modacrylic polymers exemplified in the modacrylic fiber A can be appropriately used, and a detailed description thereof is omitted here. Among these, as the halogen-containing monomer, from the viewpoint of enhancing the solid-phase flame retardant effect and improving the synergistic effect with the gas-phase flame retardant effect of the tin- and zinc-containing compound contained in the modacrylic fiber A, a modified polyacrylic polymer containing a vinyl halide as a constituent component is preferred, and a modified polyacrylic polymer containing vinyl chloride as a constituent component is more preferred.

[0042] From the perspectives of flame retardancy, spinnability, fiber strength, and cloth strength, modacrylic fiber B preferably comprises, for example, 93-99.5% by mass of the modacrylic polymer and 0.5-7% by mass of a magnesium compound. More preferably, it comprises 94-98.8% by mass of the modacrylic polymer and 1.2-6% by mass of a magnesium compound. Even more preferably, it comprises 94.5-90.2% by mass of the modacrylic polymer and 1.8-5.5% by mass of a magnesium compound. Modacrylic fiber B may optionally contain other additives such as an antistatic agent, a heat discoloration inhibitor, a light fastness enhancer, a whiteness enhancer, a devitrification inhibitor, and a colorant. The content of these other additives in modacrylic fiber B may be 10% or less, 5% or less, or 1% or less by mass.

[0043] Modified polyacrylonitrile fiber B can be any of short fibers and long fibers, and can be appropriately selected in the method of use. The single fiber fineness of modified polyacrylonitrile fiber B is appropriately selected according to the use of fabrics, work clothes, etc., and can be 1 to 50 dtex, 1.5 to 30 dtex, or 1.7 to 15 dtex. The fiber length of modified polyacrylonitrile fiber B is appropriately selected according to the use of fabrics, work clothes, etc. For example, short fibers (for example, fiber length 0.1 to 5 mm), short fibers (for example, fiber length 15 to 176 mm, 20 to 160 mm, 25 to 138 mm, or 30 to 128 mm), and long fibers (filaments) can be mentioned.

[0044] For example, from the perspective of durability, the single fiber strength of the modacrylic fiber B is preferably 1.0 to 4.0 cN / dtex, more preferably 1.5 to 3.5 cN / dtex. For example, from the perspective of practicality, the elongation of the modacrylic fiber B is preferably 15 to 40%, more preferably 20 to 30%.

[0045] The method for producing the modified polyacrylonitrile fiber B is not particularly limited, but it can preferably be produced by spinning a composition comprising a modified polyacrylonitrile polymer and a magnesium compound. Specifically, spinning can be performed by known methods such as wet spinning, dry spinning, and semi-wet / dry spinning. For example, in the case of wet spinning, a spinning solution comprising the modified polyacrylonitrile polymer, the magnesium compound, and a solvent is used. The spinning solution is extruded through a nozzle into a coagulation bath to coagulate the solution, followed by stretching, washing, and drying. The fibers can then be stretched and heat-relaxed as needed to produce the fibers. Furthermore, if desired, the fibers can be crimped and cut to a specified fiber length. The spinning solution can be produced by dissolving the modified polyacrylonitrile polymer in a solvent and then adding the magnesium compound thereto. Alternatively, a dispersion obtained by dispersing the magnesium compound in a solvent can be added to a solution obtained by dissolving the modified polyacrylonitrile polymer in a solvent. Examples of the solvent include organic solvents such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and acetone; and inorganic solvents such as aqueous thiocyanate solutions and aqueous nitric acid solutions.

[0046] The flame-retardant fabric contains a tin- and zinc-containing compound derived from modacrylic fiber A and a magnesium compound derived from modacrylic fiber B. Since it contains substantially no antimony compounds, concerns about environmental impact can be reduced while also reducing costs. Specifically, in one or more embodiments of the present invention, modacrylic fiber A, modacrylic fiber B, and the flame-retardant fabric contain substantially no antimony compounds. In this specification, the term "substantially free of antimony compounds" means that antimony compounds are not intentionally added to the fibers or fabric as flame retardants. If antimony compounds are present as inclusions, the term "substantially free of antimony compounds" applies.

[0047] As the cellulosic fibers, one or more selected from natural cellulosic fibers and regenerated cellulosic fibers can be used.

[0048] Examples of the natural cellulose fibers include natural cellulose fibers such as cotton fibers, kapok fibers, flax fibers, hemp fibers, ramie fibers, jute fibers, Manila hemp fibers, and kenaf fibers.

[0049] Examples of the regenerated cellulose fibers include rayon fibers, flame-retardant rayon fibers, lyocell fibers, and flame-retardant lyocell fibers. Rayon fibers are obtained by wet-spinning cellulose xanthate obtained by reacting an alkali and carbon disulfide with a cellulose raw material, dissolving the resulting cellulose xanthate in caustic soda. Lyocell fibers are obtained by wet-spinning the cellulose raw material by dissolving the cellulose xanthate in N-methylmorpholine N-oxide without modifying the cellulose raw material.

[0050] The above-mentioned cellulose fibers may be either short fibers or long fibers, and can be appropriately selected in the method of use. The single fiber fineness of the above-mentioned cellulose fibers is appropriately selected according to the use of the fabric or work clothes, and is preferably 1 to 50 dtex, more preferably 1.5 to 30 dtex, and even more preferably 1.7 to 15 dtex. The fiber length of the above-mentioned cellulose fibers is appropriately selected according to the use of the fabric or work clothes. For example, short-cut fibers (for example, fiber length 0.1 to 5 mm), short fibers (for example, fiber length 15 to 176 mm, 20 to 160 mm, 25 to 138 mm, or 30 to 128 mm), or completely uncut long fibers (filaments) can be mentioned.

[0051] The flame-retardant fabric preferably comprises 25-60% by mass of modacrylic fiber A, 5-25% by mass of modacrylic fiber B, and 30-70% by mass of the cellulosic fiber. More preferably, it comprises 25-50% by mass of modacrylic fiber A, 8-25% by mass of modacrylic fiber B, and 40-70% by mass of the cellulosic fiber. Even more preferably, it comprises 25-50% by mass of modacrylic fiber A, 10-25% by mass of modacrylic fiber B, and 40-60% by mass of the cellulosic fiber. By adjusting the content of modacrylic fiber A and modacrylic fiber B within the above range, a synergistic effect is more readily achieved, and both gas-phase and solid-phase flame retardancy are more likely to be improved. Furthermore, when the content of the cellulosic fiber is within the above range, both gas-phase and solid-phase flame retardancy are excellent, and the hand feel is improved.

[0052] The flame-retardant fabric may contain other fibers in addition to modacrylic fiber A, modacrylic fiber B, and cellulose fibers, without impairing the objects and effects of the present invention. Examples of these other fibers include conductive fibers, heat-resistant fibers, and high-strength and high-elasticity fibers. For example, conductive fibers include metal fibers, metal-plated fibers, copper compound-coated fibers, and fibers containing conductive substances. Heat-resistant fibers include meta-aramid fibers, polyoxadiazole fibers, polyimide fibers, and polyamide-imide fibers. High-strength and high-elasticity fibers include nylon fibers, polyester fibers, para-aramid fibers, and polyarylate fibers. The flame-retardant fabric may contain no more than 10% by mass, no more than 8% by mass, no more than 5% by mass, or no more than 1% by mass of these other fibers.

[0053] The above-mentioned other fibers may be either short fibers or long fibers, and may be appropriately selected in the method of use. The single fiber fineness of the above-mentioned other fibers may be appropriately selected according to the use of the fabric, work clothes, etc., and may be 1 to 50 dtex, 1.5 to 30 dtex, or 1.7 to 15 dtex. The fiber length of the above-mentioned other fibers may be appropriately selected according to the use of the fabric, fabric, work clothes, etc. For example, short fibers (fiber length 0.1 to 5 mm), short fibers (fiber length 15 to 176 mm, 20 to 160 mm, 25 to 138 mm, or 30 to 128 mm), and long fibers (filaments) may be mentioned.

[0054] The form of the flame-retardant fabric is not particularly limited, and examples thereof include woven and knitted fabrics. The weave of the fabric is not particularly limited and may be plain, twill, or satin weaves, or patterned fabrics produced using specialized looms such as dobbies or jacquards. The weave of the knitted fabric is also not particularly limited and may be circular, weft, or warp knitted. For excellent durability, the flame-retardant fabric is preferably a woven fabric, and more preferably a twill weave.

[0055] The flame-retardant fabric exhibits excellent flame retardancy, with the thickness of the carbonized film after a combustion test according to ISO 15025 being 4.0 mm or greater, preferably 4.5 mm or greater, and more preferably 5.0 mm or greater. Furthermore, the afterflame time measured in a combustion test according to ISO 15025 is preferably 3.0 seconds or less, more preferably 2.0 seconds or less, and particularly preferably 1.0 second or less. Furthermore, the afterglow time measured in a combustion test according to ISO 15025 is preferably 2.0 seconds or less, more preferably 1.0 second or less, and particularly preferably 0 seconds. Consequently, the fabric is suitable for use as flame-retardant workwear for firefighting operations, such as protective clothing and firefighter uniforms. Specifically, the combustion test according to ISO 15025 was conducted as described in the Examples.

[0056] The weight per unit area of ​​the flame retardant fabric is not particularly limited, but is preferably 150 to 400 g / m2 from the viewpoint of hand feel. 2 , more preferably 200 to 380 g / m 2 , more preferably 220 to 350 g / m 2 .

[0057] Examples of fiber products in which the flame-retardant fabric can be used for various fiber products (applications) include the following.

[0058] (1) Materials for clothing and daily necessities

[0059] Clothes (including tops, underwear, sweaters, vests, and pants, etc.), gloves, socks, scarves, hats, bedding, pillows, cushions, stuffed dolls, etc.

[0060] (2) Work clothes

[0061] Protective clothing and fire-fighting clothing, etc., are work clothes worn by firefighters (including cold-proof clothing)

[0062] (3)Interior decoration materials

[0063] Chair covers, curtains, wallpaper, carpets, etc.

[0064] (4) Industrial materials

[0065] Filters, refractory fillings, lining materials, etc.

[0066] (Flame retardant work clothes)

[0067] In one or more embodiments of the present invention, the flame retardant fabric can be suitably used as a work clothing fabric that requires flame retardancy. The flame retardant work clothes can be manufactured using the flame retardant fabric by a known sewing method. Since the flame retardant fabric has excellent gas phase flame retardancy and solid phase flame retardancy, the flame retardant work clothes also have excellent gas phase flame retardancy and solid phase flame retardancy. The flame retardant work clothes can be used as work clothes for all operations that require flame retardancy. For example, although not particularly limited, it can be used as protective clothing (firefighting clothing) worn by firefighters, protective clothing worn at work sites where fires may occur, such as petroleum, petrochemical, coal mining, electricity and welding, and work clothes worn at work sites where dust explosions are envisioned, such as metal processing.

[0068] Example

[0069] The present invention will be described in more detail below with reference to the following examples.

[0070] The measurement and evaluation methods used in Examples and Comparative Examples are as follows.

[0071] (Median particle size (D50))

[0072] The particle size distribution of the compound in the dispersion of the compound was measured by laser diffraction using a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., particle size distribution analyzer LA-950V2) to determine the average particle size D50.

[0073] (Flame retardancy)

[0074] A combustion test was conducted according to ISO 15025:2016 (Procedure A) to determine the afterflame and afterglow times. The thickness of the fabric after the combustion test was also measured as follows. The combustion test method according to ISO 15025:2016 (Procedure A) involves applying a 25 ± 2 mm flame to the fabric for evaluation, placed on a predetermined stand, at a right angle and 17 ± 1 mm away, for 10 seconds.

[0075] <Carbonized Film Thickness>

[0076] The thickness of the carbonized film was measured using a digital thickness gauge DTG01 manufactured by ASONE Co., Ltd. A carbonized film with a thickness exceeding 1 mm was judged to have foaming, and a carbonized film with a thickness of 1 mm or less was judged to have no foaming.

[0077] (Production Example 1)

[0078] An acrylic copolymer consisting of 51.5% by mass of acrylonitrile, 47.0% by mass of vinylidene chloride and 1.5% by mass of sodium p-styrene sulfonate obtained by emulsion polymerization of acrylonitrile, vinylidene chloride and sodium p-styrene sulfonate was dissolved in dimethyl sulfoxide in such a way that the concentration of the modified polyacrylonitrile polymer became 30% by mass. In the obtained solution of the modified polyacrylonitrile polymer, 10 parts by mass of hexahydroxytin zinc (manufactured by SCL Italia SpA, trade name "ZHS") was added relative to 100 parts by mass of the modified polyacrylonitrile polymer to prepare a spinning solution. The hexahydroxytin zinc was added in advance in such a way that the concentration became 28% by mass relative to 100% by mass of dimethyl sulfoxide and was uniformly dispersed to prepare a dispersion liquid. In the dispersion liquid of the hexahydroxytin zinc, the median particle size (D50) of the hexahydroxytin zinc measured by laser diffraction method was 2.0 μm. The resulting spinning solution was extruded into a 50% by mass aqueous dimethyl sulfoxide solution using a nozzle with an aperture of 0.08 mm and 300 holes, coagulated, washed with water, and dried at 120°C. After drying, the fibers were stretched to 3 times their original density and then heat-treated at 145°C for 5 minutes to produce modacrylic fibers. The resulting modacrylic fibers had a single fiber fineness of 1.7 dtex, a tenacity of 2.4 cN / dtex, an elongation of 29%, and a cut length of 38 mm.

[0079] (Production Example 2)

[0080] A modified polyacrylonitrile polymer composed of 49% by mass of acrylonitrile, 49.5% by mass of vinyl chloride, and 1.5% by mass of sodium p-styrene sulfonate, obtained by emulsion polymerization of acrylonitrile, vinyl chloride, and sodium p-styrene sulfonate, was dissolved in dimethylformamide at a resin concentration of 30% by mass. To the resulting modified polyacrylonitrile polymer solution, 5 parts by mass of silane-coupled magnesium hydroxide (manufactured by Kyowa Chemical Industry Co., Ltd., trade name "KISUMA 5P") was added per 100 parts by mass of the modified polyacrylonitrile polymer to prepare a spinning solution. The magnesium hydroxide was previously added at a concentration of 30% by mass relative to 100% by mass of dimethyl sulfoxide and uniformly dispersed therein, and used as a dispersion prepared. In the magnesium hydroxide dispersion, the median particle size (D50) of the magnesium hydroxide, as measured by laser diffraction, was 2.5 μm. The resulting spinning solution was extruded into a 50% by mass aqueous dimethyl sulfoxide solution using a nozzle with an aperture of 0.08 mm and 300 holes, coagulated, washed with water, and dried at 120°C. After drying, the fibers were stretched to 3 times their original length and then heat-treated at 145°C for 5 minutes to produce modacrylic fibers. The resulting modacrylic fibers had a single fiber fineness of 1.72 dtex, a tenacity of 2.7 cN / dtex, an elongation of 28%, and a cut length of 38 mm.

[0081] (Production Example 3)

[0082] Modified polyacrylonitrile fibers were produced in the same manner as in Production Example 1, except that 8 parts by mass of zinc tin hexahydroxylate and 2 parts by mass of magnesium hydroxide were added to a modified polyacrylonitrile polymer solution per 100 parts by mass of the modified polyacrylonitrile polymer to prepare a spinning solution. The resulting modified polyacrylonitrile fibers had a single fiber fineness of 1.7 dtex, a tenacity of 2.4 cN / dtex, an elongation of 29%, and a cut length of 38 mm.

[0083] (Production Example 4)

[0084] Modified polyacrylonitrile fibers were produced in the same manner as in Production Example 1, except that 10 parts by mass of zinc borate (manufactured by Sakai Chemical Co., Ltd.) was added to a modified polyacrylonitrile polymer solution per 100 parts by mass of the modified polyacrylonitrile polymer to prepare a spinning solution. The zinc borate was used as a dispersion prepared by adding 28% by mass of zinc borate to 100% by mass of dimethyl sulfoxide and uniformly dispersing the mixture. The median particle size (D50) of the zinc borate in the zinc borate dispersion, as measured by laser diffraction, was 2.0 μm. The resulting modified polyacrylonitrile fibers had a single fiber fineness of 1.7 dtex, a strength of 2.4 cN / dtex, an elongation of 29%, and a cut length of 38 mm.

[0085] The types and contents of the flame retardants in the modacrylic fibers obtained in Production Examples 1 to 4 are shown in Table 1 below.

[0086] Table 1

[0087]

[0088] (Examples 1, 2, Comparative Examples 1 to 6)

[0089] <Production of flame-retardant fabrics>

[0090] Modified polyacrylonitrile fiber and cotton (natural cotton fiber with a cut length of 31 mm or less) were blended in the prescribed mass ratio shown in Table 2 below, and the fibers were defibered using a sample roller carding machine SC-500 manufactured by Yamato Machinery Co., Ltd., and slivers were produced using a small drawing frame TSM-DFS manufactured by Intec Co., Ltd. Subsequently, the slivers were used to produce spun yarn using a high-speed roving frame FL200 manufactured by Toyota Industries, and a 20 / 1 count spun yarn was produced using a high-speed spinning frame UA37 manufactured by Howa Industry Co., Ltd. This spun yarn was used to produce a yarn with a unit weight of approximately 275 g / m2 using a computerized weft knitting machine SSG series 122FC manufactured by Shima Seiki Co., Ltd. 2 Single-jersey fabric.

[0091] The flame retardancy of the fabrics obtained in Examples 1 and 2 and Comparative Examples 1 to 6 was measured as described above. The flame retardancy results are shown in Table 3 below.

[0092] Table 2

[0093]

[0094] Table 3

[0095]

[0096] As shown in Table 3, the fabrics of Examples had an afterflame time of 1.0 second or less, as measured by the combustion test method according to ISO 15025:2016 (Procedure A), indicating excellent gas-phase flame retardancy. Furthermore, the thickness of the carbonized film after the combustion test according to ISO 15025:2016 (Procedure A) was 4 mm or greater, indicating excellent solid-phase flame retardancy.

[0097] On the other hand, in Comparative Example 1, since no modified polyacrylonitrile fiber containing a magnesium compound was used, no carbonized film foaming occurred. Furthermore, in Comparative Example 2, where the content of tin and zinc compounds in the fabric was low, combustion occurred during the combustion test, resulting in poor fire extinguishing performance and poor gas-phase flame retardancy. In Comparative Example 3, which used a modified polyacrylonitrile fiber containing zinc hydroxystannate and magnesium hydroxide, no carbonized film foaming occurred, and sufficient flame retardancy was not achieved. In Comparative Example 4, which used a modified polyacrylonitrile fiber containing zinc borate as the modacrylic fiber, no carbonized film foaming occurred. In Comparative Examples 5 and 6, which combined a modified polyacrylonitrile fiber containing zinc borate and no tin and zinc compounds with a modified polyacrylonitrile fiber containing a magnesium compound, combustion occurred during the combustion test, resulting in poor fire extinguishing performance, and no carbonized film foaming. Both gas-phase and solid-phase flame retardancy were poor.

[0098] From the data of the Examples and Comparative Examples, it can be seen that when the modified polyacrylonitrile fiber A, which is substantially free of magnesium compounds and contains compounds containing tin and zinc, and the modified polyacrylonitrile fiber B, which is substantially free of tin and zinc compounds and contains magnesium compounds, are used in combination, a synergistic effect is specifically exerted, and the gas phase flame retardancy and solid phase flame retardancy are improved.

[0099] The present invention is not particularly limited, and preferably includes, for example, the following embodiments.

[0100] [1] A flame-retardant fabric comprising a modacrylic fiber A, a modacrylic fiber B, and a cellulose fiber, wherein the modacrylic fiber A contains a compound containing tin and zinc and contains substantially no magnesium compound, and the modacrylic fiber B contains a magnesium compound and contains substantially no tin and zinc compound, the flame-retardant fabric containing 2.0% by mass or more of the tin and zinc compound derived from the modacrylic fiber A, and the thickness of a carbonized film of the flame-retardant fabric after a combustion test in accordance with ISO 15025 is 4.0 mm or more.

[0101] [2] The flame-retardant fabric according to [1], wherein the flame-retardant fabric contains 0.1% by mass or more of a magnesium compound derived from the modacrylic fiber B.

[0102] [3] The flame-retardant fabric according to [1] or [2], wherein the compound containing tin and zinc comprises a zinc stannate compound.

[0103] [4] The flame-retardant fabric according to any one of [1] to [3], wherein the magnesium compound contains magnesium hydroxide.

[0104] [5] The flame-retardant fabric according to any one of [1] to [4], wherein the modacrylic fiber A contains 5 to 20% by mass of the compound containing tin and zinc.

[0105] [6] The flame-retardant fabric according to any one of [1] to [5], wherein the modacrylic fiber B contains 0.5 to 7% by mass of the magnesium compound.

[0106] [7] The flame-retardant fabric according to any one of [1] to [6], wherein the modacrylic fiber B comprises a modacrylic polymer containing vinyl chloride as a structural unit.

[0107] [8] The flame-retardant fabric according to any one of [1] to [7], comprising 25 to 60% by mass of the modacrylic fiber A, 5 to 25% by mass of the modacrylic fiber B, and 30 to 70% by mass of the cellulosic fiber.

[0108] [9] The flame-retardant fabric according to any one of [1] to [8], wherein the cellulosic fibers include natural cellulosic fibers.

[0109]

[10] The flame-retardant fabric according to any one of [1] to [9], wherein the afterflame time in the ISO 15025 combustion test is 1.0 second or less.

[0110]

[11] A flame-retardant workwear comprising the flame-retardant fabric according to any one of [1] to

[10] .

Claims

1. A flame-retardant fabric comprising a modacrylic fiber A, a modacrylic fiber B, and a cellulosic fiber, wherein: Modacrylic fiber A contains compounds containing tin and zinc and contains substantially no magnesium compound. Modacrylic fiber B contains a magnesium compound and substantially no compounds containing tin and zinc. The flame-retardant fabric contains 2.0% by mass or more of a compound containing tin and zinc derived from the modacrylic fiber A. The flame-retardant fabric has a carbonized film having a thickness of 4.0 mm or more after a combustion test in accordance with ISO 15025.

2. The flame-retardant fabric according to claim 1, wherein The flame-retardant fabric contains 0.1% by mass or more of a magnesium compound derived from the modacrylic fiber B.

3. The flame-retardant fabric according to claim 1, wherein The compound containing tin and zinc includes a zinc stannate compound.

4. The flame-retardant fabric according to claim 1, wherein The magnesium compound comprises magnesium hydroxide.

5. The flame-retardant fabric according to claim 1, wherein The modacrylic fiber A contains 5 to 20% by mass of the compound containing tin and zinc.

6. The flame-retardant fabric according to claim 1, wherein The modacrylic fiber B contains 0.5 to 7% by mass of the magnesium compound.

7. The flame-retardant fabric according to claim 1, wherein Modacrylic fiber B comprises a modacrylic polymer containing vinyl chloride as a structural unit.

8. The flame-retardant fabric according to claim 1, wherein The fiber composition comprises 25 to 60% by mass of the modacrylic fiber A, 5 to 25% by mass of the modacrylic fiber B, and 30 to 70% by mass of the cellulosic fiber.

9. The flame-retardant fabric according to claim 1, wherein The cellulosic fibers include natural cellulosic fibers.

10. The flame-retardant fabric according to claim 1, wherein In the ISO15025 combustion test, the afterflame time is less than 1.0 second.

11. Flame-retardant work clothes comprising the flame-retardant fabric according to claims 1 to 10.

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