Modacrylic fiber and method for producing same

Abstract

One or more embodiments of the present invention relate to a modacrylic fiber comprising a magnesium compound and a disperse dye. The magnesium compound is present inside the modacrylic fiber. The number of magnesium-containing particles located on the surface of the modacrylic fiber and having a particle diameter of 50 nm or greater is 5 / 10 μm2 or less. One or more embodiments of the present invention relate to a method for producing a modacrylic fiber comprising a step for dying a modacrylic fiber containing a magnesium compound in a dyebath containing a disperse dye., the pH of the dyebath being 6.5-10. As a result, provided are: a modacrylic fiber that provides good color development properties and texture and has superior fire resistance; and a method for producing the modacrylic fiber.

Description

Modacrylic fiber and its manufacturing method

[0001] The present invention relates to modacrylic fibers containing dyes and flame retardants, and methods for making same.

[0002] In order to improve the flame retardancy of modacrylic fibers, flame retardants have been incorporated. For example, Patent Document 1 describes incorporating a magnesium compound as a flame retardant into modacrylic fibers. Meanwhile, modacrylic fibers may require dyeing depending on their use or purpose. Modacrylic fibers are generally dyed using cationic dyes or disperse dyes, preferably cationic dyes. For example, Patent Document 2 describes dyeing a spun yarn containing acrylic shrinkable fibers and modacrylic flat fibers with cationic dyes and disperse dyes in a dye bath adjusted to a pH of about 3.5.

[0003] JP2024-049407A JP10-96169A

[0004] However, when the magnesium-containing modacrylic fiber described in Patent Document 1 is dyed with a cationic dye or a disperse dye in an acidic dye bath, there are problems in that the flame retardancy, color development, and texture are poor.

[0005] In order to solve the above-mentioned problems of the prior art, the present invention provides a modacrylic fiber that has good color development and texture as well as excellent flame retardancy, and a method for producing the same.

[0006] One or more embodiments of the present invention are directed to a modacrylic fiber containing a magnesium compound and a disperse dye, wherein the magnesium compound is present inside the fiber, and the number of magnesium-containing particles having a particle diameter of 50 nm or more on the fiber surface of the modacrylic fiber is 5 / 10 μm. 2 The following relates to modacrylic fibers:

[0007] One or more embodiments of the present invention relate to a method for producing a modacrylic fiber, comprising the step of dyeing a modacrylic fiber containing a magnesium compound therein in a dye bath containing a disperse dye, wherein the pH of the dye bath is 6.5 or more and 10 or less.

[0008] According to one or more embodiments of the present invention, a modacrylic fiber having good colorability and texture as well as excellent flame retardancy can be provided. Furthermore, according to one or more embodiments of the production method of the present invention, a modacrylic fiber having good colorability and texture as well as excellent flame retardancy can be obtained.

[0009] 1 is a scanning electron microscope (SEM) image (10,000x magnification) of the fiber surface of undyed modacrylic fiber of Production Example 1. 2 is a SEM image (10,000x magnification) of the fiber surface of dyed modacrylic fiber of Comparative Example 1. 3 is a SEM image (10,000x magnification) of the fiber surface of dyed modacrylic fiber of Example 1. 4 is a scanning transmission electron microscope (STEM) image (8,000x magnification) of the fiber surface of dyed modacrylic fiber of Comparative Example 1. 5 is an EDX result of a portion 1 on the fiber surface of the dyed modacrylic fiber of Comparative Example 1 where no particles are present. 6 is an EDX result of a portion 2 on the fiber surface of the dyed modacrylic fiber of Comparative Example 1 where particles are present. 7 is an EDX result of a portion 3 on the fiber surface of the dyed modacrylic fiber of Comparative Example 1 where particles are present.

[0010] The inventors of the present invention have conducted extensive research to improve the color development, texture, and flame retardancy of dyed modacrylic fibers containing magnesium compounds. As a result, they have found that dyed modacrylic fibers containing magnesium compounds inside the fibers can be dyed with a disperse dye in a dye bath having a pH of 6.5 or higher to obtain dyed modacrylic fibers that have good color development and texture as well as high flame retardancy.

[0011] Specifically, when modacrylic fibers containing a magnesium compound inside the fiber are dyed with a disperse dye in a dye bath with a pH of 6.5 or higher, the dyed modacrylic fibers are almost free of magnesium-containing particles on their surface, exhibiting good color development and texture, and exhibiting flame retardancy that is suppressed and maintains the same good flame retardancy as before dyeing. On the other hand, when modacrylic fibers containing a magnesium compound inside the fiber are dyed with a disperse dye or cationic dye in an acidic dye bath with a pH of less than 6.5, the dyed modacrylic fibers exhibit many magnesium-containing particles of a certain size on their surface, resulting in inferior flame retardancy and texture compared to before dyeing, and in the case of disperse dyes, poor color development. Furthermore, when modacrylic fibers containing a magnesium compound inside the fiber are dyed with a cationic dye in a dye bath with a pH of 6.5 or higher, discoloration and fading occur.

[0012] When the dyebath is alkaline, with a pH of 6.5 or higher, and particularly preferably above 7.0, and the dye is a disperse dye, it is presumed that magnesium compounds present inside the modacrylic fiber are hardly eluted and / or precipitated on the fiber surface during the dyeing process, and the disperse dye penetrates well into the interior of the modacrylic fiber, resulting in dyed modacrylic fibers with good color development and texture, as well as excellent flame retardancy similar to that before dyeing. On the other hand, when the dye is a disperse dye but the dyebath is acidic, with a pH of less than 6.5, most of the magnesium compounds present inside the modacrylic fiber are eluted and / or precipitated on the fiber surface during the dyeing process, forming particles with a diameter of 50 nm or more, and poor penetration of the disperse dye into the interior of the modacrylic fiber is also presumed to result in poor flame retardancy, color development, and texture. Furthermore, when the dyebath is acidic with a pH of less than 6.5 and the dye is a cationic dye, the cationic dye penetrates well into the interior of the modacrylic fiber during the dyeing process, but many of the magnesium compounds present inside the modacrylic fiber are eluted and / or precipitated on the fiber surface to form particles with a diameter of 50 nm or more, which is presumed to result in good color development but poor feel and flame retardancy. Furthermore, when the dyebath is alkaline with a pH of 6.5 or higher, particularly above 7.0, and the dye is a cationic dye, the magnesium compounds present inside the modacrylic fiber are hardly eluted and / or precipitated on the fiber surface during the dyeing process, but the cationic dye becomes unstable in a dyebath with a pH of 6.5 or higher, particularly an alkaline bath with a pH of above 7.0, and is presumed to cause discoloration and fading.

[0013] 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.

[0014] (Modacrylic Fiber) In one or more embodiments of the present invention, the modacrylic fiber is a dyed modacrylic fiber containing a disperse dye (hereinafter also referred to as modacrylic fiber I). The disperse dye is not particularly limited, and a general disperse dye can be used as appropriate, for example, an azo disperse dye having an azo structure, an anthraquinone disperse dye having an anthraquinone structure, and a condensation disperse dye. The disperse dye is preferably a disperse dye having one or more structures selected from the group consisting of an azo structure and an anthraquinone structure, and more preferably a disperse dye having an azo structure and an anthraquinone structure in the same molecule.

[0015] Modacrylic fiber I contains a magnesium compound, and the magnesium compound is present inside the fiber. The magnesium compound present inside the fiber functions as a flame retardant, improving the flame retardancy of the modacrylic fiber. The content of the magnesium compound is not particularly limited, but is preferably 3 to 10 parts by mass, and more preferably 4 to 9 parts by mass, per 100 parts by mass of the polymer constituting modacrylic fiber I. When the content of the magnesium compound is 3 parts by mass or more, the flame retardancy of modacrylic fiber I is further improved. When the content of the magnesium compound is 10 parts by mass or less, the fiber strength of modacrylic fiber I is improved.

[0016] From the viewpoints of flame retardancy and fiber strength, Modacrylic Fiber I preferably contains 1.2 to 3.8 mass % of magnesium (derived from a magnesium compound), and more preferably 1.6 to 3.4 mass %. In this specification, the content of magnesium (derived from a magnesium compound) in Modacrylic Fiber I can be measured by inductively coupled plasma optical emission spectroscopy (ICP-OES), and specifically, can be measured as described in the Examples.

[0017] The magnesium compound is not particularly limited, but examples thereof include magnesium oxide, magnesium peroxide, magnesium hydroxide, magnesium fluoride, magnesium diboride, magnesium nitride, magnesium sulfide, magnesium carbonate, calcium magnesium carbonate, etc. Among these, from the viewpoint of being easily present inside the fiber, one or more selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate are preferred, and magnesium hydroxide is more preferred.

[0018] The magnesium hydroxide is not particularly limited, but examples that can be used include powder obtained by pulverizing natural bruce ore, powder obtained by neutralizing an aqueous magnesium salt solution with an alkali, powder obtained by treating magnesium hydroxide particles with phosphate, borate, or the like, and powder obtained by hydrating magnesium oxide to gradually produce magnesium hydroxide. The magnesium hydroxide may have a coating layer formed by adsorbing an adsorbable substance on the periphery of the magnesium hydroxide particles or by surface treatment with a surface treatment agent. Among these, magnesium hydroxide having a coating layer formed by surface treatment with a silane coupling agent is preferred from the viewpoint of static electricity suppression.

[0019] The magnesium compound preferably has an average particle size, expressed as a median diameter (D50), of 0.3 μm or more, more preferably 0.3 to 2.0 μm, and even more preferably 0.5 to 1.5 μm. When the average particle size is 0.3 μm or more, the surface area of ​​the magnesium compound particles does not increase too much, which suppresses static electricity generation in fiber processing steps such as spinning and makes processing easier. When the average particle size is 2.0 μm or less, clogging of the spinneret does not occur in the spinning step, which is preferable from a manufacturing perspective. In this specification, the average particle size of the magnesium compound can be measured, for example, by laser diffraction / scattering in the case of a powder, and can be measured by laser diffraction / scattering or dynamic light scattering in the case of a dispersion (dispersion liquid) in water or an organic solvent.

[0020] In modacrylic fiber I, the number of magnesium-containing particles having a particle diameter of 50 nm or more on the fiber surface is 5 / 10 μm 2or less, 4 pieces / 10 μm 2 Preferably, the number is 3 / 10 μm or less. 2 More preferably, it is 2 / 10 μm or less. 2 More preferably, it is 1 / 10 μm or less. 2 Even more preferably, it is 0 / 10 μm or less. 2 It is particularly preferable that the number of particles having a particle diameter of 50 nm or more on the fiber surface is 100%. In this specification, the number of particles having a particle diameter of 50 nm or more on the fiber surface can be measured by observation with a high-resolution scanning electron microscope, and specifically, it can be measured as described in the Examples. In this specification, the particle diameter of a particle on the fiber surface means the length of the longest straight line connecting any two points on the periphery of a particle in an SEM image (8000x magnification) of the fiber surface. In addition, in this specification, whether particles having a particle diameter of 50 nm or more on the fiber surface contain magnesium can be confirmed by scanning transmission electron microscope-energy dispersive X-ray spectroscopy (STEM-EDX), and specifically, it can be confirmed as described in the Examples.

[0021] The polymer constituting modacrylic fiber I mainly contains a modacrylic copolymer. In this specification, "the polymer constituting the fiber mainly contains a modacrylic copolymer" means that the modacrylic copolymer content is 80% by mass or more, assuming that the total mass of the polymer constituting the fiber is 100% by mass. The polymer constituting modacrylic fiber I preferably contains 85% by mass or more of the modacrylic copolymer, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be composed of 100% by mass of the modacrylic copolymer.

[0022] The modacrylic copolymer is not particularly limited, but preferably contains 35 to 65 mass% of acrylonitrile and 35 to 65 mass% of a halogen-containing monomer, more preferably 40 to 60 mass% of acrylonitrile and 40 to 60 mass% of a halogen-containing monomer, or preferably 35 to 65 mass% of acrylonitrile, 35 to 65 mass% of a halogen-containing monomer, and 0 to 3 mass% of another copolymerizable vinyl monomer, more preferably 40 to 60 mass% of acrylonitrile, 40 to 60 mass% of a halogen-containing monomer, and 0 to 3 mass% of another copolymerizable vinyl monomer.

[0023] Examples of halogen-containing monomers include halogen-containing vinyl and halogen-containing vinylidene. Examples of halogen-containing vinyl include vinyl chloride and vinyl bromide, and examples of halogen-containing vinylidene include vinylidene chloride and vinylidene bromide. These halogen-containing monomers may be used alone or in combination of two or more. Among them, one or more selected from the group consisting of vinyl chloride and vinylidene chloride are preferred, and vinyl chloride is more preferred.

[0024] The other copolymerizable vinyl monomers are not particularly limited, but include, for example, unsaturated carboxylic acids such as acrylic acid and methacrylic acid and their salts, methacrylic acid esters such as methyl methacrylate, esters of unsaturated carboxylic acids such as glycidyl methacrylate, vinyl esters such as vinyl acetate and vinyl butyrate, and monomers containing a sulfonic acid group. The monomers containing a sulfonic acid group are not particularly limited, but include, for example, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, isoprene sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid, as well as metal salts and amine salts thereof, such as sodium salts. These other copolymerizable vinyl monomers may be used alone or in combination of two or more. From the standpoint of dyeability, it is preferable that the other copolymerizable vinyl monomer is a monomer containing a sulfonic acid group.

[0025] The modacrylic copolymer can be obtained by known polymerization methods such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization, among which suspension polymerization, emulsion polymerization, and solution polymerization are preferred from an industrial viewpoint.

[0026] Modacrylic fiber I may contain, as needed, a flame retardant other than a magnesium compound, as long as the effects of the present invention are not impaired. As the flame retardant other than a magnesium compound, a flame retardant that does not leach or emit into the environment is preferred. From the perspective of environmental impact, modacrylic fiber I is preferably substantially free of antimony compounds. In this specification, "substantially free of antimony compounds" means that no antimony compounds are intentionally added to modacrylic fiber I as flame retardants, and that the content of antimony compounds in modacrylic fiber I is approximately 0% by mass. Furthermore, modacrylic fiber I may contain, as needed, other additives such as antistatic agents (also referred to as antistatic agents), thermal discoloration inhibitors, light resistance improvers, whiteness improvers, and devitrification inhibitors, as long as the effects of the present invention are not impaired.

[0027] The modacrylic fiber I may be a short fiber or a long fiber, and the type can be appropriately selected depending on the method of use. The single fiber fineness of the modacrylic fiber I is appropriately selected depending on the application of the textile product, such as fabric or workwear, and may be 1 to 50 dtex, 1.5 to 30 dtex, or 1.7 to 15 dtex. The fiber length of the modacrylic fiber I is appropriately selected depending on the application of the textile product, such as fabric or workwear. Examples of the modacrylic fiber I include short-cut fibers (e.g., fiber length 0.1 to 5 mm), short fibers (e.g., fiber length 15 to 176 mm, 20 to 160 mm, 25 to 138 mm, or 30 to 128 mm), and long fibers (filaments).

[0028] From the viewpoint of durability, for example, the modacrylic fiber I preferably has a single fiber strength of 1.0 to 4.0 cN / dtex, and more preferably 1.5 to 3.5 cN / dtex. From the viewpoint of practicality, for example, the modacrylic fiber I preferably has an elongation of 15 to 40%, and more preferably 20 to 30%. In this specification, the single fiber strength and elongation of the fiber can be measured in accordance with JIS L 1013:2010 or JIS L 1015:2010.

[0029] From the viewpoint of high flame retardancy, Modacrylic Fiber I preferably has a limiting oxygen coefficient (LOI value) of 36 or more, more preferably 38 or more, and even more preferably 40 or more. In this specification, the LOI value can be measured as described in the examples.

[0030] (Method for Producing Modacrylic Fiber I) In one or more embodiments of the present invention, the method for producing modacrylic fiber I is not particularly limited, but preferably includes a step of dyeing a modacrylic fiber containing a magnesium compound inside the fiber (hereinafter also referred to as modacrylic fiber A) in a dye bath containing a disperse dye and having a pH of 6.5 to 10. This prevents the magnesium compound present inside modacrylic fiber A from eluting and / or precipitating on the fiber surface during the dyeing step, and the disperse dye is appropriately impregnated into the inside of the modacrylic fiber, thereby obtaining modacrylic fiber I that has good color development and texture as well as excellent flame retardancy. As the disperse dye, any of those described in the description of modacrylic fiber I can be used as appropriate. For example, a disperse dye having one or more structures selected from the group consisting of an azo structure and an anthraquinone structure is preferred, and a disperse dye having an azo structure and an anthraquinone structure in the same molecule is more preferred.

[0031] From the viewpoints of more effectively suppressing the elution and / or precipitation of the magnesium compound inside the modacrylic fiber A onto the fiber surface and further enhancing color development, the pH of the dye bath (dyeing solution) is preferably more than 7.0 and not more than 10, more preferably 7.5 or more and 9.5 or less, and even more preferably 8 or more and not more than 9. The pH of the dye bath can be adjusted with a pH adjuster such as a pH alkalinity adjuster.

[0032] The concentration of the disperse dye in the dye solution is not particularly limited and can be adjusted appropriately depending on the desired hue. For example, from the viewpoints of hue, cost, and color fastness, the concentration may be 0.0001 to 7% owf (on the weight of fiber) or 0.01 to 3% owf, i.e., 0.0001 to 7% by mass or 0.01 to 3% by mass relative to the mass of the modacrylic fiber A.

[0033] The dye bath may contain dyeing auxiliaries such as a dispersing and leveling agent and a dyeing accelerator (also referred to as a carrier) within a range that does not impair the effects of the present invention. Commercially available dispersing and leveling agents and dyeing accelerators may be used as appropriate. The concentrations of the dispersing and leveling agent and dyeing accelerator are not particularly limited; for example, the dispersing and leveling agent may be 0.5 to 3.0 g / L, and the accelerator may be 1.0 to 3.0 g / L.

[0034] The liquor ratio is not particularly limited, but may be 1:10 or more, and from the viewpoint of reducing costs and the burden on the environment due to waste liquid treatment, it is preferably 1:30 or less, and more preferably 1:20 or less.

[0035] The dyeing temperature (temperature of the dye bath) is not particularly limited, but may be, for example, from the viewpoint of dyeability, 30 to 100° C., 40 to 100° C., or 50 to 100° C. The dyeing time is not particularly limited, but may be, for example, from the viewpoint of productivity and suppression of dye unevenness, 30 to 120 minutes or 60 to 120 minutes.

[0036] After dyeing, washing, dehydration, and drying can be carried out. Washing can be done with water, but reduction washing may also be carried out if necessary.

[0037] The reduction rate of the magnesium content in modacrylic fiber after the dyeing process relative to the magnesium content in modacrylic fiber before the dyeing process (hereinafter simply referred to as "reduction rate of magnesium content in the dyeing process") is preferably 15% or less, more preferably 12% or less, even more preferably 10% or less, even more preferably 7% or less, and particularly preferably 6% or less. The reduction rate of the magnesium content in modacrylic fiber during the dyeing process can be calculated using the following formula 1. In the following formula 1, Cont1 is the magnesium content in the modacrylic fiber before dyeing (modacrylic fiber A), and Cont2 is the magnesium content in the modacrylic fiber after dyeing (modacrylic fiber I). [Formula 1] Reduction rate of magnesium content (%) = (Cont1 - Cont2) / Cont1 × 100

[0038] The polymer constituting modacrylic fiber A mainly contains a modacrylic copolymer. The polymer constituting modacrylic fiber A preferably contains 85% by mass or more of the modacrylic copolymer, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be 100% by mass of the modacrylic copolymer. The polymer constituting modacrylic fiber A may contain other polymers in addition to the modacrylic copolymer, as necessary, within a range that does not impair the effects of the present invention. The content of the other polymers may be 1 to 20 parts by mass, 2 to 15 parts by mass, or 3 to 10 parts by mass per 100 parts by mass of the modacrylic copolymer. As the modacrylic copolymer and other polymers, those described in the description of modacrylic fiber I can be used as appropriate.

[0039] From the viewpoints of the flame retardancy, texture, color development, fiber strength, etc. of the modacrylic fiber after dyeing (i.e., modacrylic fiber I), modacrylic fiber A preferably contains 3 to 10 parts by mass, and more preferably 4 to 9 parts by mass, of a magnesium compound per 100 parts by mass of the polymer constituting modacrylic fiber A. As the magnesium compound, those described in the description section of modacrylic fiber I can be used appropriately, and for example, one or more selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate are preferred, with magnesium hydroxide being more preferred.

[0040] The method for producing modacrylic fiber A is not particularly limited, but it can be produced by spinning a spinning composition containing a polymer constituting modacrylic fiber A and a magnesium compound. Specifically, the spinning can be carried out by a known method such as a wet spinning method, a dry spinning method, or a semi-dry / semi-wet method. The spinning composition may contain 3 to 10 parts by mass, or 4 to 9 parts by mass, of the magnesium compound per 100 parts by mass of the polymer constituting modacrylic fiber A.

[0041] For example, in the case of wet spinning, the modacrylic fiber A can be produced in the same manner as in the case of general modacrylic fibers, except that a spinning solution containing a polymer constituting the modacrylic fiber A, a magnesium compound, and a solvent is used. The spinning solution is extruded through a nozzle into a coagulation bath to coagulate, and then stretched, washed with water, and dried, and if necessary, stretched and heat-relaxed to produce the modacrylic fiber. If necessary, the fiber may be crimped and cut to a predetermined fiber length. Examples of solvents include organic solvents such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and acetone, and inorganic solvents such as an aqueous rhodanide solution and an aqueous nitric acid solution.

[0042] (Fiber Assembly) The modacrylic fiber I can be used in a fiber assembly. The fiber assembly may consist solely of the modacrylic fiber I, or may contain other fibers in addition to the modacrylic fiber I. The fiber assembly may contain 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more of the modacrylic fiber I. As the other fibers, natural fibers, regenerated fibers, and synthetic fibers can be used as appropriate.

[0043] Examples of natural fibers include natural cellulose fibers such as cotton, kapok, flax, hemp, ramie, jute, Manila hemp, and kenaf; and natural animal fibers such as wool, mohair, cashmere, camel, alpaca, angora, and silk.

[0044] Examples of regenerated fibers include regenerated cellulose fibers such as rayon fibers, polynosic fibers, cupra fibers, and lyocell fibers, regenerated collagen fibers, regenerated protein fibers, cellulose acetate fibers, and promix fibers.

[0045] Examples of synthetic fibers include polyester fibers, polyamide fibers, polylactic acid fibers, acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, polychlor fibers, polyethylene fibers, polyurethane fibers, polyoxymethylene fibers, polytetrafluoroethylene fibers, benzoate fibers, polyphenylene sulfide fibers, polyether ether ketone fibers, polybenzazole fibers, polyimide fibers, and polyamide-imide fibers.Furthermore, synthetic fibers that may be used include flame-retardant polyesters, polyethylene naphthalate fibers, melamine fibers, acrylate fibers, polybenzoxide fibers, oxidized acrylic fibers, carbon fibers, glass fibers, and activated carbon fibers.

[0046] The form of the fiber assembly is not particularly limited, and may be, for example, any of yarn, nonwoven fabric, woven fabric, knitted fabric, braided fabric, etc. The yarn may be a spun yarn or a filament yarn.

[0047] Examples of nonwoven fabrics include wet-laid nonwoven fabrics, carded nonwoven fabrics, air-laid nonwoven fabrics, thermally bonded nonwoven fabrics, chemically bonded nonwoven fabrics, needle-punched nonwoven fabrics, hydroentangled nonwoven fabrics, and stitch-bonded nonwoven fabrics.

[0048] Examples of woven fabrics include plain weave, twill weave, satin weave, varied plain weave, varied twill weave, varied satin weave, patterned weave, one-ply weave, double weave, multi-weave, warp pile weave, weft pile weave, and leno weave.

[0049] Knitted fabrics include circular knitting, weft knitting, warp knitting, pile knitting, etc., and examples include plain knitting, jersey knitting, rib knitting, smooth knitting (double knitting), elastic knitting, pearl knitting, Denbigh knitting, cord knitting, atlas knitting, chain knitting, and insertion knitting.

[0050] The fiber assembly may be used to form a textile product, such as the following: (1) Clothing and daily necessities: clothing (including jackets, underwear, sweaters, vests, pants, etc.), gloves, socks, scarves, hats, bedding, pillows, cushions, stuffed toys, etc. (2) Special clothing: protective clothing, firefighting clothing, work clothes, cold weather clothing, etc. (3) Interior materials: upholstery, curtains, wallpaper, carpets, etc. (4) Industrial materials: filters, flame-resistant padding, lining materials, etc.

[0051] The following examples further illustrate one or more embodiments of the present invention, but the present invention is not limited to the examples.

[0052] The measurement and evaluation methods used in the examples and comparative examples are as follows.

[0053] (Median diameter (D50)) The particle diameter distribution of magnesium hydroxide was measured by a laser diffraction method using a laser diffraction / scattering particle diameter distribution analyzer (LA-950V2, manufactured by Horiba, Ltd.), and the median diameter D50 was determined.

[0054] (Limiting Oxygen Index (LOI Value)) The LOI value was measured in accordance with JIS L 1091 E. Specifically, a twisted sample having a length of 60 mm was prepared using 0.25 g of fiber, and the sample was ignited and then removed from the flame, and the minimum oxygen index required for the sample to burn for 50 mm or more was measured.

[0055] (Observation of Fiber Surface) The fiber surface was observed with a high-resolution scanning electron microscope (FE-SEM) (manufactured by Zeiss, "ULTRAplus"), and five equally spaced areas were divided in the width direction of the fiber (transverse direction to the fiber axis, direction perpendicular to the fiber axis), and each area was photographed at 8000 times magnification. 2The number of magnesium-containing particles with a particle diameter of 50 nm or more in the range (3.16 μm in the width direction × 3.16 μm in the axial direction) was measured, and the average value was calculated. If the width size of each of the five equally divided areas was less than 3.16 μm, the axial size was adjusted to approximately 10 μm near the center of the width direction of each photograph. 2 The number of magnesium-containing particles having a particle diameter of 50 nm or more within the range is counted, and the average value is calculated. Here, the particle diameter of a particle means the length of the longest line among lines connecting any two points on the periphery of a particle in an SEM image.

[0056] (Elemental analysis of fiber surface) After the fiber was amorphously (non-crystallinely) coated with osmium (Os) using an osmium coater, the types and contents of elements in areas where particles were present and areas where particles were not present on the fiber surface were examined using a scanning transmission electron microscope (STEM-EDX) equipped with an energy dispersive X-ray spectrometer (EDX) (manufactured by Hitachi High-Technologies Corporation, "HD-2700").

[0057] (Measurement of Magnesium Content in Fiber) The magnesium (Mg) content in modacrylic fiber was quantified using inductively coupled plasma (ICP) optical emission spectroscopy (ICP-OES). First, a sample with a dry weight of 1.000 g was heated on a hot plate with 5 mL of concentrated nitric acid, treated by wet decomposition, and then diluted to 25 mL with pure water. The resulting diluted solution was introduced into an ICP-OES device (Shimadzu Corporation, "ICPE-9800"), and the Mg emission intensity was measured at a wavelength of 285.213 nm. The device selected the optimal wavelength from a graph for each element, measured the emission intensity three times, and calculated the average element concentration in the spray solution. Based on this data, the element concentration in the fiber was calculated, and the Mg content (mass%) in the fiber was calculated by comparison with a standard solution. In addition, the reduction rate of the magnesium (Mg) content in modacrylic fiber during the dyeing process was calculated using the following formula 1. In the following formula 1, Cont1 is the magnesium content in the modacrylic fiber before dyeing, and Cont2 is the magnesium content in the modacrylic fiber after dyeing. [Formula 1] Reduction rate of magnesium content (%) = (Cont1 - Cont2) / Cont1 x 100

[0058] (Production Example 1) A modacrylic copolymer consisting of 51% by mass of acrylonitrile, 49% by mass of vinyl chloride, and 1% by mass of sodium p-styrenesulfonate was dissolved in dimethyl sulfoxide so that the modacrylic copolymer content was 28% by mass. To the obtained modacrylic copolymer solution, 5 parts by mass of magnesium hydroxide (Kyowa Chemical Industry Co., Ltd., "KISUMA 5P", silane-coupled magnesium hydroxide) having an average particle size represented by the median diameter (D50) of 0.72 μm was added per 100 parts by mass of the modacrylic copolymer, and the mixture was uniformly mixed to obtain a spinning solution. The resulting spinning solution was extruded into a 57% by mass aqueous solution of dimethyl sulfoxide at 25°C using a nozzle with a hole diameter of 0.07 mm and 115,000 holes, washed with water, dried at 130 to 140°C for 20 minutes, stretched 2.6 times at 135°C, and then heat-treated at 155°C for 15 minutes to obtain a modacrylic fiber having a single fiber fineness of 1.7 dtex. The resulting modacrylic fiber had a single fiber strength of 2.8 cN / dtex and an elongation of 23%.

[0059] (Production Example 2) A modacrylic fiber having a single fiber fineness of 1.7 dtex was obtained in the same manner as in Example 1, except that magnesium hydroxide was not added and a modacrylic copolymer solution was used as the spinning dope. The obtained modacrylic fiber had a single fiber strength of 2.7 cN / dtex and an elongation of 27%.

[0060] Example 1 The modacrylic fiber obtained in Production Example 1 was immersed in a dye bath consisting of the following dye solution 1, treated at a bath ratio of 1:10 at 60°C for 5 minutes, then heated to 98°C at a temperature increase rate of 1°C / min, and dyed at 98°C for 60 minutes. Thereafter, the fiber was cooled to 80°C at a temperature decrease rate of 1°C / min, and then sodium hydrosulfite was added to the dye bath to a concentration of 1 g / L, followed by reduction washing and drying at 70°C for 60 minutes to obtain a dyed modacrylic fiber. Dye liquor 1: A water mixture (pH = 8.5) containing 3.0% owf of an azo disperse dye (manufactured by DyStar, "DIANIX BLUE CC", color index: Disperse Blue 360), 1 g / L of a pH alkalinity adjuster (manufactured by DyStar, "DIASERVER AD-95"), 1 g / L of a dispersing and leveling agent (manufactured by NICCA CHEMICAL, "NIKKA SUNSALT 7000"), and 1 g / L of a dye accelerator (carrier) (manufactured by TANATEX, "TANAVOL-DAP").

[0061] Example 2 Dyed modacrylic fibers were obtained in the same manner as in Example 1, except that the azo disperse dye was changed to an anthraquinone disperse dye (manufactured by DyStar Corporation, "DIANIX BLUE HLA", color index: Disperse Blue 354).

[0062] Example 3 Dyed modacrylic fibers were obtained in the same manner as in Example 1, except that the azo disperse dye was changed to a disperse dye having both an azo structure and an anthraquinone structure in the same molecule (manufactured by DyStar Corporation, "DIANIX BLUE PLUS", color index: Disperse Blue 60).

[0063] Example 4 Dyed modacrylic fibers were obtained in the same manner as in Example 3, except that the pH of the dye bath was adjusted to 7.5 using a pH alkalinity adjuster (DyStar's "DIASERVER AD-95").

[0064] Example 5 Dyed modacrylic fibers were obtained in the same manner as in Example 3, except that the pH of the dye bath was adjusted to 9.5 using a pH alkalinity adjuster (DyStar's "DIASERVER AD-95").

[0065] (Example 6) Dyed modacrylic fiber was obtained in the same manner as in Example 3, except that a pH acidity adjuster (manufactured by Mitejima Chemical Co., Ltd., "ULTRA MT LEVEL #650") was used as the pH adjuster to adjust the pH of the dye bath to 6.5.

[0066] Comparative Example 1 Dyed modacrylic fiber was obtained in the same manner as in Example 3, except that a pH acidity adjuster (manufactured by Mitejima Chemical Co., Ltd., "UlTRA MT #110" phosphoric acid) was used as the pH adjuster to adjust the pH of the dye bath to 2.5.

[0067] Comparative Example 2 Dyed modacrylic fibers were obtained in the same manner as in Comparative Example 1, except that the dye was changed to an azo-based cationic dye (manufactured by Nissei Chemical Industries, Ltd., "NICHILON BLUE GRL") and no dispersing and leveling agent was used.

[0068] Comparative Example 3 Dyed modacrylic fiber was obtained in the same manner as in Comparative Example 2, except that the pH adjuster was changed to a pH alkalinity adjuster ("DIASERVER AD-95" manufactured by DyStar Corporation) and the pH of the dye bath was adjusted to 8.5.

[0069] Reference Example 1 Dyed modacrylic fibers were obtained in the same manner as in Comparative Example 2, except that the modacrylic fibers obtained in Production Example 2 were used.

[0070] Table 1 below shows the types and concentrations of dyes used in the Examples, Comparative Examples, and Reference Examples, as well as the pH of the dye baths.

[0071]

[0072] The fiber surfaces of the modacrylic fiber of Production Example 1 and the dyed modacrylic fibers obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were observed with a scanning electron microscope (SEM) as described above, and the number of particles with a particle size of 50 nm or more was measured. The results are shown in Table 2 below. Also, Figures 1 to 3 show SEM images of the fiber surfaces of the modacrylic fiber of Production Example 1, the dyed modacrylic fiber of Comparative Example 1, and the dyed modacrylic fiber of Example 1, respectively. The types of elements at particle-present and particle-free locations on the fiber surface were examined with a scanning transmission electron microscope (STEM-EDX) as described above. Figure 4 shows an STEM image of the dyed modacrylic fiber of Comparative Example 1 analyzed with STEM-EDX, and Figures 5 to 7 show the EDX results.

[0073] As can be seen from Figures 1 and 3, no particles with a particle diameter of 50 nm or more were present on the fiber surface of the modacrylic fiber of Production Example 1 and the dyed modacrylic fiber of Example 1. On the other hand, as can be seen from Figure 2, numerous particles with a particle diameter of 50 nm or more (indicated by arrows) were present on the fiber surface of the dyed modacrylic fiber of Comparative Example 1. Figure 5 shows the EDX results for point 1 in Figure 4 where no particles were present on the fiber surface of the dyed modacrylic fiber of Comparative Example 1, and Figures 6 and 7 show the EDX results for points 2 and 3 in Figure 4 where particles were present on the fiber surface of the dyed modacrylic fiber of Comparative Example 1. Figures 4 to 7 reveal that the particles with a particle diameter of 50 nm present on the fiber surface contain magnesium. The magnesium in the magnesium-containing particles (hereinafter also referred to as Mg-containing particles) is presumed to be derived from magnesium compounds originally present inside the fibers that dissolved and / or precipitated on the fiber surface during dyeing in an acidic dye bath.

[0074]

[0075] As can be seen from the results in Table 2, in Examples 1 to 6 in which dyeing was carried out using a disperse dye in a dye bath with a pH of 6.5 to 10, the dyed modacrylic fiber had 2 Mg-containing particles per 10 μm on the fiber surface. 2In particular, in Examples 1 to 5, which were dyed using a disperse dye in an alkaline dyebath with a pH greater than 7.0 and less than 10, no Mg-containing particles were present on the fiber surface of the dyed modacrylic fibers. Furthermore, as can be seen from the results in Table 1, in Examples 1 to 6, the reduction rate of the magnesium content of the modacrylic fibers during the dyeing process was 15% or less. In particular, in Examples 1 to 5, the reduction rate of the magnesium content of the modacrylic fibers during the dyeing process was 6% or less, resulting in little elution or precipitation of magnesium compounds during the dyeing process. Furthermore, the LOI values ​​of the dyed modacrylic fibers of Examples 1 to 5 were almost the same as the LOI value of the modacrylic fiber of Production Example 1 before dyeing, demonstrating high flame retardancy. Although the LOI value of the dyed modacrylic fiber of Example 6 was slightly lower than the LOI value of the modacrylic fiber of Production Example 1 before dyeing, it still exhibited high flame retardancy similar to that of the modacrylic fiber of Production Example 1 before dyeing. The dyed modacrylic fibers of Examples 1 to 6 had good color development, with a small ΔE compared to the reference color of the dyed modacrylic fiber of Reference Example 1. The dyed modacrylic fibers of Examples 1 to 6 also had a smooth fiber surface and a good texture.

[0076] On the other hand, in Comparative Example 1, in which dyeing was performed using a disperse dye in an acidic dye bath of less than pH 6.5, and Comparative Example 2, in which dyeing was performed using a cationic dye in an acidic dye bath of less than pH 6.5, 5 particles / 10 μm were observed on the surface of the dyed modacrylic fiber. 2Many Mg-containing particles with particle diameters of 50 nm or more were present, and the fiber surface had a rough feel and poor texture. Furthermore, the magnesium content derived from magnesium compounds in the dyed modacrylic fibers of Comparative Examples 1 and 2 was significantly lower than the magnesium content derived from magnesium compounds in the modacrylic fiber of Production Example 1 before dyeing, and the LOI value was also significantly lower than the LOI value of the modacrylic fiber of Production Example 1 before dyeing, resulting in poor flame retardancy. The dyed modacrylic fiber of Comparative Example 1 had a large ΔE compared to the reference color of the dyed modacrylic fiber of Reference Example 1, and exhibited poor color development. Furthermore, in Comparative Example 3, which was dyed using a cationic dye in a dyebath with a pH greater than 6.5, the dyed modacrylic fiber had a large ΔE compared to the reference color of the dyed modacrylic fiber of Reference Example 1, and exhibited poor color development.

[0077] The present invention is not particularly limited, but preferably includes, for example, the following embodiments: [1] A modacrylic fiber containing a magnesium compound and a disperse dye, wherein the magnesium compound is present inside the modacrylic fiber, and the number of magnesium-containing particles having a particle diameter of 50 nm or more on the fiber surface of the modacrylic fiber is 5 / 10 μm. 2A modacrylic fiber having the following: [2] The modacrylic fiber according to [1], wherein the content of the magnesium compound is 3 to 10 parts by mass per 100 parts by mass of the polymer constituting the modacrylic fiber. [3] The modacrylic fiber according to [1] or [2], wherein the magnesium compound is at least one compound selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate. [4] The modacrylic fiber according to any one of [1] to [3], wherein the disperse dye has at least one structure selected from the group consisting of an azo structure and an anthraquinone structure. [5] The modacrylic fiber according to [4], wherein the disperse dye has an azo structure and an anthraquinone structure in the same molecule. [6] The modacrylic fiber according to any one of [1] to [5], wherein the modacrylic fiber contains 1.2 to 3.8% by mass of magnesium. [7] A method for producing a modacrylic fiber, comprising a step of dyeing a modacrylic fiber containing a magnesium compound therein in a dyebath containing a disperse dye, wherein the pH of the dyebath is 6.5 or more and 10 or less. [8] The method for producing a modacrylic fiber according to [7], wherein the content of the magnesium compound is 3 to 10 parts by mass per 100 parts by mass of the polymer constituting the modacrylic fiber. [9] The method for producing a modacrylic fiber according to [7] or [8], wherein the magnesium compound is one or more selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate.

[10] The method for producing a modacrylic fiber according to any of [7] to [9], wherein the magnesium content in the modacrylic fiber after the dyeing step is reduced by 15% or less compared to the magnesium content in the modacrylic fiber before the dyeing step.

[0078] 1. Areas where no particles exist on the fiber surface. 2., 3. Areas where particles exist on the fiber surface.

Claims

1. A modacrylic fiber containing a magnesium compound and a disperse dye, wherein the magnesium compound is present inside the modacrylic fiber, and the number of magnesium-containing particles having a particle diameter of 50 nm or more on the fiber surface of the modacrylic fiber is 5 / 10 μm. 2 The following are modacrylic fibers.

2. The modacrylic fiber according to claim 1, wherein the content of said magnesium compound is 3 to 10 parts by mass per 100 parts by mass of the polymer constituting said modacrylic fiber.

3. The modacrylic fiber according to claim 1 or 2, wherein the magnesium compound is at least one selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate.

4. The modacrylic fiber according to claim 1 or 2, wherein the disperse dye has one or more structures selected from the group consisting of azo-based structures and anthraquinone-based structures.

5. The modacrylic fiber according to claim 4, wherein the disperse dye has an azo structure and an anthraquinone structure in the same molecule.

6. The modacrylic fiber according to claim 1, wherein the modacrylic fiber contains 1.2 to 3.8% by mass of magnesium.

7. A method for producing modacrylic fiber, comprising the step of dyeing modacrylic fiber containing a magnesium compound inside the fiber in a dye bath containing a disperse dye, wherein the pH of the dye bath is 6.5 or more and 10 or less.

8. The method for producing modacrylic fiber according to claim 7, wherein the content of the magnesium compound is 3 to 10 parts by mass per 100 parts by mass of the polymer constituting the modacrylic fiber.

9. The method for producing modacrylic fiber according to claim 7 or 8, wherein the magnesium compound is at least one selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate.

10. A method for producing modacrylic fiber as described in claim 7, wherein the magnesium content in the modacrylic fiber after the dyeing step is reduced by 15% or less compared to the magnesium content in the modacrylic fiber before the dyeing step.

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