Polyurethane elastic fibers and their production methods

Abstract

[Problem] The object of the present invention is to provide polyurethane elastic fibers with excellent fabric properties and stability of fabric properties over time, achieved by including a specific polyurethane in the polyurethane elastic fibers, the specific polyurethane having a salt structure in its molecular structure in which specific functional groups are ionicly bonded to each other; and to provide a method for producing such polyurethane elastic fibers. Another object of the present invention is to provide a polyurethane elastic fiber that allows for easier fiber inventory control and processing condition management during use, and can be used to obtain fabrics with stable fabric properties and fabric quality; and to provide a method for producing such polyurethane elastic fibers. [Solution] A polyurethane elastic fiber comprising polyurethane A and additive B. Polyurethane A: A polyurethane using a polymeric diol, diisocyanate, and chain extender as starting materials and not containing a tertiary amine in the backbone. Additive B: A polyurethane or polyurea using a diol and / or diamine and diisocyanate as starting materials and having a tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, the tertiary amine nitrogen being ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine.

Description

Technical Field

[0001] This invention relates to a polyurethane elastic fiber and a method for producing the same. Background Technology

[0002] The polyurethane used in polyurethane elastic fibers can be broadly classified into polyurethane urethane elastic fibers, which mainly use diols as chain extenders, and polyurethane urea elastic fibers, which mainly use diamines as chain extenders.

[0003] Polyurethane elastic fibers composed of the former (urethane urethane) possess high strength and high elasticity, and Patent Document 1 discloses examples of polyurethane elastic fibers whose fiber properties do not easily change over time. In the technology described in Patent Document 1, to achieve the effects of the present invention, a specific copolyol, which is not a general-purpose product, must be used as the raw material polyol.

[0004] Polyurethane elastic fibers composed of the latter (polyurethane urea) have high elasticity, but not as strong as the former. In addition, because their fiber properties change more over time than the former, problems arise in inventory control and processing condition management when using these fibers, and it is difficult to obtain fabrics with stable fabric properties and quality.

[0005] In other words, among polyurethane elastic fibers using common raw materials, there are no polyurethane elastic fibers composed of polyurethane urethane or polyurethane urea whose fiber properties do not easily change over time.

[0006] Patent document 2 discloses a polyurethane urea elastic fiber that uses a specific compound as a terminating agent in the production of polyurethane urea, the terminating agent inhibiting the increase in viscosity of the polyurethane urea solution.

[0007] Patent document 3 discloses examples of polyurethane elastic fibers containing a benzophenone UV absorber having at least one sulfonic acid group in the molecule. Some of the sulfonic acid groups in these UV absorbers can be salts of alkali metals, such as sodium or potassium.

[0008] [Existing Technical Documents]

[0009] [Patent Documents]

[0010] [Patent Document 1] JPH11-081045A

[0011] [Patent Document 2] JP2003-155624A

[0012] [Patent Document 3] JP 2011-144491A Summary of the Invention

[0013] [The problem to be solved by this invention]

[0014] However, there are no polyurethane elastic fibers made from universal raw materials that provide the stretchability and fiber properties characteristic of polyurethane elastic fibers that do not easily change over time. Therefore, an object of the present invention is to provide a polyurethane elastic fiber with excellent fabric properties and stability of fabric properties over time, and to provide a method for producing such a polyurethane elastic fiber. Another object of the present invention is to provide a polyurethane elastic fiber that allows for easier inventory control and processing condition management during use, and can be used to obtain fabrics with stable fabric properties and fabric quality; and to provide a method for producing such a polyurethane elastic fiber.

[0015] [A method used to solve problems]

[0016] To address this problem, the present invention employs the following methods.

[0017] (1) A polyurethane elastic fiber comprising polyurethane A and additive B.

[0018] Polyurethane A: A polyurethane that uses polymeric diols, diisocyanates, and chain extenders as starting materials and does not contain tertiary amines in the backbone.

[0019] Additive B: A polyurethane or polyurea using diols and / or diamines and diisocyanates as starting materials and having tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, wherein the tertiary amine nitrogen is ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine.

[0020] (2) The polyurethane elastic fiber according to (1), wherein additive B is polyurethane or polyurea, wherein the diol starting material comprises a diol containing a tertiary amine as the main component.

[0021] (3) The polyurethane elastic fiber according to (1) or (2), wherein additive B is polyurethane or polyurea, wherein the diamine starting material comprises a diamine containing a tertiary amine as the main component.

[0022] (4) The polyurethane elastic fiber according to any one of (1) to (3), wherein the molecular weight of the sulfonic acid compound in additive B is 96 or greater and 300 or less.

[0023] (5) The polyurethane elastic fiber according to any one of (1) to (4), wherein the amount of additive B is 0.1% by weight or more and 10% by weight or less.

[0024] (6) The polyurethane elastic fiber according to any one of (1) to (5), wherein the end group of additive B is N,N-dialkylaminourea.

[0025] (7) A method for producing polyurethane elastic fibers, the method comprising: spinning a spinning solution containing polyurethane A and additive B.

[0026] Polyurethane A: A polyurethane that uses polymeric diols, diisocyanates, and chain extenders as starting materials and does not contain tertiary amines in the backbone.

[0027] Additive B: A polyurethane or polyurea using diols and / or diamines and diisocyanates as starting materials and having tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, wherein the tertiary amine nitrogen is ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine.

[0028] (8) The method for producing polyurethane elastic fibers according to (7), the method comprising: adding additive solution b and additive solution c to spinning solution a to obtain spinning solution containing polyurethane A and additive B; and spinning the spinning solution.

[0029] Spinning solution a: Spinning solution containing the above-mentioned polyurethane A.

[0030] Additive solution b: An additive solution containing polyurethane or polyurea, wherein the polyurethane or polyurea uses diol and / or diamine and diisocyanate as starting materials and has tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone.

[0031] Additive solution c: An additive solution containing a sulfonic acid compound with a molecular weight of 96 or greater and 300 or less.

[0032] (9) The method for producing polyurethane elastic fibers according to (7), the method comprising: mixing additive solution b and additive solution c together to obtain additive solution d containing additive B, said additive B having a sulfonic acid amine salt structure, wherein the tertiary amine and sulfonic acid are ionicly bonded in the molecular structure; mixing spinning solution a and additive solution d together to obtain spinning solution; and spinning said spinning solution.

[0033] [Effects of the Invention]

[0034] Because the polyurethane elastic fibers of this invention exhibit higher recovery stress and lower permanent deformation than conventional polyurethane elastic fibers within practical applications, garments using these elastic fibers offer a good fit and feel, and are easy to remove. Furthermore, these elastic fibers also possess stable mechanical properties over time, making them easy to process during covering, weaving, and knitting, whether used alone or in combination with other types of fibers for more advanced finishing. Detailed Implementation

[0035] The following is a detailed description of the present invention.

[0036] First, the polyurethane used in this invention will be described.

[0037] In the following description, a polyurethane that uses a polymeric glycol, diisocyanate, and chain extender as starting materials and does not contain a tertiary amine in the backbone is referred to as "polyurethane A," and a polyurethane or polyurea that uses a glycol and / or diamine and diisocyanate as starting materials and has tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone is referred to as "additive B," wherein the tertiary amine nitrogen is ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine. Note that "polyurethane" includes polyurethane urethane and polyurethane urea.

[0038] There are no particular limitations on the method used to obtain polyurethane elastic fibers containing polyurethane A and additive B, and any method can be used as long as it involves spinning a spinning solution containing polyurethane A and additive B to produce polyurethane elastic fibers. For example, a spinning solution a containing polyurethane A and an additive solution d containing additive B can be prepared separately and then mixed together to obtain a spinning solution. In another method, the raw material constituting additive B can be added to a solution containing polyurethane A, and additive solutions b and c can be mixed into spinning solution a containing polyurethane A to produce additive B and a spinning solution containing both polyurethane A and additive B, which can then be spun to obtain polyurethane fibers.

[0039] There are no particular limitations on the polyurethane A used in this invention, as long as the polymeric diol, diisocyanate, and chain extender are used as starting materials and the backbone does not contain tertiary amines. Here, using the polymeric diol, diisocyanate, and chain extender as starting materials means that the resulting polyurethane polymer has a structure derived from each component. In other words, this specification specifies the structure of the polyurethane polymer obtained using the polymeric diol, diisocyanate, and chain extender as starting materials, but equivalent structures can be formed from different raw materials, and the raw materials themselves are not specified. Similarly, even when the same raw materials are used for synthesis, there are no particular limitations on the synthesis method.

[0040] For example, polyurethane A can be a polyurethane urea polymer composed of polymeric diols, diisocyanates, and low molecular weight diamines, or a polyurethane urea polymer using polymeric diols, diisocyanates, and low molecular weight diols. It can also be a polyurethane urea using compounds with hydroxyl and amino groups in the molecule as chain extenders. Examples of polyurethanes without tertiary amines in their backbone include: (1) polyurethane urethanes composed of polymeric diols, diisocyanates, and low molecular weight diols; (2) polyurethane ureas composed of polymeric diols, diisocyanates, and low molecular weight diamines in which the low molecular weight amines are only primary and / or secondary amines; (3) polyurethane ureas in which compounds having hydroxyl and amino groups in their molecules are used as chain extenders, and the amines in the compounds having amino and hydroxyl groups in their molecules are only primary and / or secondary amines; (4) polyurethane ureas composed of polymeric diamines, diisocyanates, and low molecular weight diols in which the amines in the polymeric diamines are only primary and / or secondary amines; and (5) polyurethane ureas composed of polymeric diols, polymeric diamines, diisocyanates, and low molecular weight diamines in which the amines in the polymeric diamines and low molecular weight diamines are only primary and / or secondary amines. Preferably, polyfunctional diols or isocyanates having trifunctionality or higher are used within a range that does not impair the effects of the invention.

[0041] The structural units that are typically used to constitute the polyurethanes of this invention will now be described.

[0042] Polyether glycol, polyester glycol, or polycarbonate glycol are preferred as polymeric diols used as structural units constituting polyurethane. Polyether glycol is particularly preferred from the perspective of imparting flexibility and elasticity to the fibers.

[0043] Preferred examples of polyether glycols include polyethylene oxide, polyethylene glycol, polyethylene glycol derivatives, polypropylene glycol, polytetramethyl ether glycol (PTMG), modified PTMG (3M-PTMG) as a copolymer with tetrahydrofuran (THF) and 3-methyltetrahydrofuran, modified PTMG as a copolymer with THF and 2,3-dimethylTHF, polyols having side chains on both sides as disclosed in JP2615131B2, and random copolymers in which THF and ethylene oxide and / or propylene oxide are irregularly arranged. One or more of these polyether glycols may be blended or copolymerized and then used.

[0044] From the viewpoint of obtaining abrasion resistance and light resistance, preferred examples include butyl adipic acid, polycaprolactone diol, polyester diol, such as polyester polyols with side chains disclosed in JPS61-026612A, and polycarbonate diol disclosed in JPH02-289516A.

[0045] These polymer diols can be used alone, or two or more can be mixed together or copolymerized and then used.

[0046] From the viewpoint of obtaining elasticity, strength, and heat resistance when made into fibers, the number average molecular weight of the polymer glycol is preferably 1,000 or greater and 8,000 or less, and more preferably 1,800 or greater and 6,000 or less. When using polyols with molecular weights in this range, elastic fibers with excellent elasticity, strength, resilience, and heat resistance can be easily obtained. Molecular weight is measured by GPC and converted to polystyrene.

[0047] Aromatic diisocyanates are particularly suitable for synthesizing polyurethanes with high heat resistance and strength. Examples include diphenylmethane diisocyanate (MDI), toluene diisocyanate, 1,4-benzene diisocyanate, xylene diisocyanate, and 2,6-naphthalene diisocyanate. Preferred examples of alicyclic diisocyanates include methylene bis(cyclohexyl)isocyanate (H12MDI), isophorone diisocyanate, methylcyclohexane 2,4-diisocyanate, methylcyclohexane 2,6-diisocyanate, cyclohexane 1,4-diisocyanate, hexahydrophenylene diisocyanate, hexahydromethylphenylene diisocyanate, and octahydro-1,5-naphthalene diisocyanate. Aliphatic diisocyanates are particularly effective in inhibiting the yellowing of polyurethane urea elastic fibers. These diisocyanates can be used alone or in combination of two or more.

[0048] As described above, the chain extender used for synthesizing polyurethane A from polymeric diols and diisocyanates is preferably at least one of a low molecular weight diamine and a low molecular weight diol. When a low molecular weight diamine is used, the amine in the compound must be a compound containing only a primary amine and / or a secondary amine. The low molecular weight diol can be a compound having both a hydroxyl and an amino group in its molecule, such as ethanolamine, and the amine in the compound can be a primary amine and / or a secondary amine.

[0049] Preferred examples of low molecular weight diamines include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, hexamethylenediamine, p-phenylenediamine, p-xylenediamine, m-xylenediamine, p,p′-methylenediphenylamine, 1,3-cyclohexyldiamine, hexahydro-m-phenylenediamine, 2-methylpentamethylenediamine, and bis(4-aminophenyl)phosphine oxide. These can be used alone or in combination of two or more. Ethylenediamine is particularly preferred. Ethylenediamine can be used to readily obtain fibers with excellent elasticity, elastic recovery, and heat resistance. Triamine compounds that can form crosslinking structures, such as diethylenetriamine, can be added to these chain extenders, provided that the effects of the invention are not compromised.

[0050] Typical examples of low molecular weight diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, dihydroxyethoxybenzene, dihydroxyethylene terephthalate, and 1-methyl-1,2-ethylene glycol. One or more of these can be used. Preferred examples include ethylene glycol, 1,3-propylene glycol, and 1,4-butanediol. When used, their heat resistance increases as diol-stretched polyurethanes, and stronger fibers can be obtained.

[0051] One or more end-capping agents are preferably mixed with polyurethane A. Preferred examples of end-capping agents include monoamines such as dimethylamine, diisopropylamine, ethylmethylamine, diethylamine, methylpropylamine, isopropylmethylamine, diisopropylamine, butylmethylamine, isobutylmethylamine, isopentylmethylamine, dibutylamine, and dipentylamine; monools such as ethanol, propanol, butanol, isopropanol, allyl alcohol, and cyclopentanol; and monoisocyanates such as phenyl isocyanate.

[0052] From the viewpoint of obtaining fibers with high durability and high strength, the average molecular weight of polyurethane A used in this invention is preferably in the range of 30,000 or greater and 150,000 or less. Molecular weight is measured by GPC and converted to polystyrene.

[0053] In this invention, when additive B (which is a polyurethane or polyurea using diols and / or diamines and diisocyanates as starting materials and having tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, wherein the tertiary amine nitrogen is ionicly bonded to sulfonic acid compounds to form sulfonic acid amines) is included in a polyurethane elastic fiber containing polyurethane A having the above-described basic composition, polyurethane elastic fibers with excellent fiber properties and stability over time can be obtained without compromising the inherent elasticity of the polyurethane elastic fibers, in addition to methods for producing polyurethane elastic fibers. Here, using diols and / or diamines and diisocyanates as starting materials means that the resulting polyurethane polymer has a structure derived from each component. In other words, in this specification, the structure of the polyurethane or polyurea polymer obtained using diols and / or diamines and diisocyanates as starting materials is specified, but equivalent structures can be formed from different raw materials, and the raw materials themselves are not specified. Similarly, even when the same raw materials are used for synthesis, there are no particular limitations on the synthesis method.

[0054] Additive B has a tertiary amine in its backbone. Therefore, polyurethanes or polyureas with a tertiary amine in their backbone are polyurethane or polyurea polymers whose starting material is a diol containing a tertiary nitrogen-containing diol as a main component and / or a diamine containing a tertiary nitrogen-containing diamine as a main component and a diisocyanate. Additive B preferably has N,N-dialkylaminourea end groups. Compounds with a tertiary nitrogen in the main chain and N,N-dialkylaminourea at the ends, despite having low concentrations of N,N-dialkylaminourea, can exhibit high heat resistance during dyeing and can achieve polyurethane elastic fibers with higher strength and elasticity.

[0055] Preferred examples of tert-azo diols that may be used include N-methyl-N,N-diethanolamine, N-methyl-N,N-dipropanolamine, N-methyl ester-N,N-diisopropanolamine, N-butyl-N,N-diethanolamine, N-tert-butyl-N,N-diethanolamine, N-octadecane-N,N-diethanolamine, N-benzyl-N,N-diethanolamine, N-tert-butyl-N,N-diisopropanolamine, and piperazine derivatives such as dihydroxyethylpiperazine and dihydroxyisopropylpiperazine. Particularly preferred are N-tert-butyl-N,N-diethanolamine or N-benzyl-N,N-diethanolamine.

[0056] Preferred examples of tertiary-azodiamines that can be used include N-methyl-3,3′-iminobis(propylamine), N-butyl-aminobis(propylamine), N-methyl-aminobis(ethylamine), N-tert-butyl-aminobis(propylamine), piperazine-N,N′-bis(3-aminopropyl), and piperazine-N,N′-bis(2-aminoethyl). Particularly preferred are N-methyl-3,3′-iminobis(propylamine) or piperazine-N,N′-bis(3-aminopropyl).

[0057] Preferred examples of diisocyanates that can be used for additive B include aliphatic diisocyanates such as methylene bis(4-cyclohexyl isocyanate), isophorone diisocyanate, lysine diisocyanate, and DDI derived from dimer acids. Methylene bis(4-cyclohexyl isocyanate) or isophorone diisocyanate are particularly preferred.

[0058] As described above, the terminal group of additive B is preferably an aminourea group. Any method common in the art can be used to introduce an aminourea group into the end of additive B, but a preferred example is reacting a substituted hydrazine with a diisocyanate to form an aminourea terminal group. Preferred examples of substituted hydrazines include N,N-dimethylhydrazine, N,N-diethylhydrazine, N,N-dipropylhydrazine, N,N-diisopropylhydrazine, N,N-dibutylhydrazine, N,N-diisobutylhydrazine, N,N-dihydroxyethylhydrazine, and N,N-dihydroxyisopropylhydrazine. N,N-dimethylhydrazine and N,N-dihydroxyethylhydrazine are particularly preferred.

[0059] Particularly preferred examples of additive B include polyurethanes produced by the reaction of N-tert-butyl-N,N-diethanolamine with methylenebis(4-cyclohexylamine), polyurethanes produced by the reaction of N-tert-butyl-N,N-diethanolamine and methylenebis(4-cyclohexyl isocyanate) at the terminal with N,N-dimethylhydrazine, and polyureas produced by the reaction of N-methyl-3,3′-iminobis(propylamine) with methylenebis(4-cyclohexyl isocyanate). There are no particular limitations on the ratio of N-tert-butyl-N,N-diethanolamine to methylenebis(4-cyclohexyl isocyanate), as long as it does not impair the effects of the invention. However, polymers produced by reactions with a ratio of 1:1.00 to 1:1.30 are preferred, and a ratio of 1:1.02 to 1:1.20 is particularly preferred.

[0060] In this invention, the sulfonic acid amine salt derived from the tertiary amine in additive B is formed through ionic bonding of the sulfonic acid compound. The sulfonic acid compound in this invention is a compound having a sulfonic acid group, and the H in the sulfonic acid group can be in a dissociated state, and the sulfonic acid compound can be a hydrate.

[0061] From the viewpoint of optimizing the stereoselectivity of the tertiary amine in the skeleton of additive B and the steric hindrance of the polyurethane molecular chain, the molecular weight of the sulfonic acid compound is preferably 96 or greater and 300 or less, and more preferably 96 or greater and 200 or less.

[0062] Examples of sulfonic acid compounds include aliphatic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, decanesulfonic acid, octadecanesulfonic acid, and cyclohexylsulfonic acid; aromatic sulfonic acids such as benzenesulfonic acid, naphthalenesulfonic acid, p-toluenesulfonic acid, phenolsulfonic acid, monochlorobenzenesulfonic acid, and anthraquinone sulfonic acid; and unsaturated aliphatic sulfonic acids such as vinylsulfonic acid, dodecenesulfonic acid, tetradecenesulfonic acid, and hexadecenesulfonic acid. Another example is sulfobetaine, which has a sulfonic acid group serving as an anionic group and an ammonium salt serving as a cationic group in its molecule. These sulfonic acid compounds may have any substituents as long as they do not impair the effects of the invention, and these substituents may be used alone or in combination of two or more. Aliphatic and aromatic sulfonic acids are particularly preferred as sulfonic acids.

[0063] In this invention, from the perspective of improving the yield of polyurethane elastic fibers, additive B is preferably a polyurethane with tertiary amine diol and organic diisocyanate as the main starting materials, and more preferably a polyurethane with tertiary amine diol and organic diisocyanate as the main starting materials, wherein the end group in the polyurethane is an N,N′-dialkylaminourea end group.

[0064] The amount of additive B in the aforementioned polyurethane elastic fibers is preferably in the range of 0.1% by weight or more and 10% by weight or less. When the amount of additive B is 0.1% by weight or more, additive B exists in the polyurethane elastic fibers at a sufficiently high concentration to stabilize the changes in fiber properties over time. From the viewpoint of achieving better stress recovery within practical application ranges, the amount of additive B in the polyurethane elastic fibers is preferably in the range of 2.0% by weight or more and 5.0% by weight or less. The additive B content of the polyurethane elastic fibers can be identified and quantified using various analytical methods such as 1H-NMR, elemental analysis, ion chromatography, and GPC.

[0065] The polyurethane elastic fibers of the present invention may contain various additives such as stabilizers and pigments. Preferred examples of light stabilizers and antioxidants include hindered phenolic reagents, such as BHT and Sumikyzer GA-80 (registered trademark) from Sumitomo Chemical Co., Ltd.; benzotriazole- and benzophenone-based reagents, such as Tinuvin (registered trademark) from Ciba Geigy Co., Ltd.; phosphorus-based reagents, such as Sumikyzer P-16 (registered trademark) from Sumitomo Chemical Co., Ltd.; hindered amine reagents; pigments, such as iron oxide and titanium oxide; minerals, such as hydrotalcite compounds, calcium magnesium carbonate, hydromagnesia, and tourmaline; inorganic materials, such as zinc oxide, cerium oxide, magnesium oxide, calcium carbonate, and carbon black; fluorine-based or silicone-based resin powders; metal soaps, such as magnesium stearate; disinfectants; and deodorants containing silver, zinc, or compounds thereof; lubricants, such as silicone and mineral oil; and antistatic agents, such as cerium oxide, betaine, and phosphoric acid. These preferably react with polymers. To improve durability against light and various nitrogen oxides, nitrogen oxide supplements, such as HN-150 from Nippon Hydrozine Co., Ltd., thermal oxidation stabilizers, such as Sumilyzer GA-80 (registered trademark) from Sumitomo Chemical Co., Ltd., or light stabilizers, such as Sumisorb 300#622 (registered trademark) from Sumitomo Chemical Co., Ltd., are preferably used. When using these stabilizers and pigments, to improve dispersibility in the fiber and stabilize the spinning process, inorganic agents that have been surface-treated with organic substances such as fatty acids, fatty acid esters and polyol-based organic substances, silane-based coupling agents, titanate-based coupling agents, or mixtures thereof are preferably used.

[0066] The method of the present invention for producing polyurethane elastic fibers will now be described in detail.

[0067] This invention relates to a method for producing polyurethane elastic fibers, the method comprising: spinning a spinning solution containing polyurethane A and additive B.

[0068] Polyurethane A: A polyurethane that uses polymeric diols, diisocyanates, and chain extenders as starting materials and does not contain tertiary amines in the backbone.

[0069] Additive B: A polyurethane or polyurea using diols and / or diamines and diisocyanates as starting materials and having tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, wherein the tertiary amine nitrogen is ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine.

[0070] There are no particular limitations on the methods used to obtain spinning solutions containing polyurethane A and additive B.

[0071] An example is a method for producing polyurethane elastic fibers, wherein the method includes: adding additive solution b and additive solution c to a spinning solution a to obtain a spinning solution; and spinning the spinning solution.

[0072] Spinning solution a: Spinning solution containing the above-mentioned polyurethane A.

[0073] Additive solution b: An additive solution containing polyurethane or polyurea, wherein the polyurethane or polyurea uses diol and / or diamine and diisocyanate as starting materials and has tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone.

[0074] Additive solution c: An additive solution containing a sulfonic acid compound with a molecular weight of 96 or greater and 300 or less.

[0075] Another method involves preparing a spinning solution a containing polyurethane A and an additive solution d containing additive B, respectively, and mixing the additive solution d with the spinning solution a to obtain polyurethane. In this case, additive solution d can be obtained by mixing additive solutions b and c together to obtain additive B with a sulfonic acid amine salt structure, wherein the tertiary amine and sulfonic acid are ionicly bonded in the molecular structure.

[0076] Polyurethane A can be prepared using melt polymerization, solution polymerization, or other methods. However, solution polymerization is particularly preferred. In solution polymerization, fewer foreign substances such as gels are generated in the polyurethane, the spinning solution is easier to spin, and it is easier to obtain polyurethane elastic fibers with low fineness. Of course, solution polymerization also has the advantage of eliminating the step of preparing the solution.

[0077] Polyurethane A, particularly suitable for the present invention, is synthesized using PTMG with a number-average molecular weight of 1800 or greater and 6000 or less as the polymer diol, MDI as the diisocyanate, and at least one of ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, and hexamethylenediamine as the chain extender.

[0078] Polyurethane A can be synthesized from the above-mentioned raw materials in solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), or solvents in which these are the main components. Preferred methods include: a so-called one-step process, in which the raw materials are added to a solvent, dissolved, heated to a suitable temperature, and reacted to form polyurethane; and a method of melting and reacting a polymeric diol and a diisocyanate and dissolving the reaction product in a solvent and reacting it with a chain extender to obtain polyurethane.

[0079] When a glycol is used as a chain extender for polyurethane A, from the perspective of excellent heat resistance, a high-side melting point in the range of 200°C or higher and 260°C or lower is preferred. This is typically achieved by controlling the type and ratio of the polymeric glycol, MDI, and glycol used. When the molecular weight of the polymeric glycol is low, a polyurethane with a high melting point can be obtained by increasing the relative ratio of MDI. Similarly, when the molecular weight of the glycol is low, a polyurethane with a high melting point can be obtained by decreasing the relative ratio of the polymeric glycol.

[0080] When the molecular weight of the polymeric diol is 1800 or higher, polymerization is preferably carried out at a ratio of (moles of MDI) / (moles of polymeric diol) ≥ 1.5 in order to raise the melting point of the high side to 200°C or higher.

[0081] When synthesizing such polymer A, it is preferable to use one type of catalyst or a mixture of two or more types of catalysts, such as amine catalysts and organometallic catalysts.

[0082] Examples of amine catalysts include N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N,N,N′,N′-tetramethylethylenediamine, N,N,N′,N′-tetramethyl-1,3-propanediamine, N,N,N′,N′-tetramethylhexanediamine, bis-2-dimethylaminoethyl ether, N,N,N′,N′,N″-pentamethyldiethyltriamine, tetramethylguanidine, and triethylamine. Diamine, N,N′-dimethylpiperazine, N-methyl-N′-dimethylaminoethyl-piperazine, N-(2-dimethylaminoethyl)morpholine, 1-methylimidazolium, 1,2-dimethylimidazolium, N,N-dimethylaminoethanol, N,N,N′-trimethylaminoethylethanolamine, N-methyl-N′-(2-hydroxyethyl)piperazine, 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylaminohexanol, and triethanolamine.

[0083] Examples of organometallic catalysts include tin octoate, dibutyltin dilaurate, and dibutyllead octoate.

[0084] The concentration of polyurethane in the resulting spinning solution containing polyurethane A is preferably in the range of 30% by weight or higher and 80% by weight or lower.

[0085] Additive solution b is an additive solution containing polyurethane or polyurea, wherein the polyurethane or polyurea uses diols and / or diamines and diisocyanates as starting materials and has tertiary amine nitrogen in its molecular structure bonded only to non-aromatic carbons in the backbone. The concentration of polyurethane or polyurea in additive solution b is preferably in the range of 30% by mass or higher and 80% by mass or lower. Except for the difference in starting materials, the method used to prepare the polyurethane or polyurea in additive solution b can be the same as the method used to prepare polyurethane A.

[0086] Additive solution c is an additive solution containing a sulfonic acid compound with a molecular weight of 96 or greater and 300 or less. The sulfonic acid compound in additive solution c is described in detail above in the description of additive B. The concentration of sulfonic acid in additive solution c is preferably in the range of 10% by mass or higher and 50% by mass or lower.

[0087] Additive solution d is a mixture of additive solution b and additive solution c, and contains additive B having a sulfonic acid amine salt structure, wherein the tertiary amine and sulfonic acid are ionicly bonded in the molecular structure. In additive solution d, the concentration of additive B is preferably in the range of 30% by mass or higher and 80% by mass or lower.

[0088] In the method for producing polyurethane elastic fibers of the present invention, the polyurethane dosage is preferably obtained by adding a solution of additive d containing additive B to a spinning solution a containing polyurethane A. The solution of additive d containing additive B can be added to the polyurethane A solution using any method common in the art. Typical methods include using a static mixer, stirring, using a homogeneous mixer, and using a twin-screw extruder.

[0089] From the viewpoint of controlling the viscosity of the polyurethane solution used for spinning based on appropriate spinning conditions, it is preferable to use one or more end-capping agents. Examples include monoamines such as dimethylamine, diisopropylamine, ethylmethylamine, diethylamine, methylpropylamine, isopropylmethylamine, diisopropylamine, butylmethylamine, isobutylmethylamine, isopentylmethylamine, dibutylamine, and dipentylamine; monools such as ethanol, propanol, butanol, isopropanol, allyl alcohol, and cyclopentanol; and monoisocyanates such as phenyl isocyanate.

[0090] The basic fibers of the present invention can be obtained by, for example, dry spinning, wet spinning, or melt spinning of the aforementioned spinning solution, and then winding the fibers. From the viewpoint of stable spinning at all finenesses from thin to thick, dry spinning is particularly preferred.

[0091] There are no particular limitations on the fineness or cross-sectional profile of the polyurethane urea elastic fibers of the present invention. For example, the cross-sectional profile of the fibers may be circular or flat.

[0092] Dry spinning methods have no particular limitations, and spinning can be carried out after selecting appropriate spinning conditions for the desired properties and spinning equipment.

[0093] For example, since the permanent strain rate and stress relaxation of the polyurethane urea elastic fibers of the present invention are particularly susceptible to the influence of the speed ratio between the guide roller and the winding machine, the spinning conditions are preferably determined based on the intended use of the fiber. From the viewpoint of obtaining polyurethane urea elastic fibers with the desired permanent strain rate and stress relaxation, it is preferable to have a speed ratio between the guide roller and the winding machine in the range of 1.10 or greater and 1.65 or less. Furthermore, from the viewpoint of improving the strength of the resulting polyurethane urea elastic fibers, the spinning speed is preferably 250 m / min or higher.

[0094] [Example]

[0095] The invention will now be described in more detail with reference to examples. However, the invention is not limited to these examples.

[0096] <Evaluation Methods>

[0097] [1] Properties of elastic fibers

[0098] To measure the fundamental properties and stability of elastic fibers over time, tensile tests were performed on sample fibers using an Instron 4502 tensile testing machine under the following conditions.

[0099] First, a 5 cm (L1) sample was stretched five times at a stretching rate of 50 cm / min, each time by 300%. The stress after the fifth 300% stretch was defined as (G1). The sample length was then held at 300% elongation for 30 seconds. The stress after holding the elongated fiber for 30 seconds was defined as (G2). Next, when the elongated sample recovered and the stress reached 0, the sample length was defined as (L2). The sample was then stretched a sixth time until it broke. The stress at break was defined as (G3), and the sample length at break was defined as (L3). Furthermore, the strain and stress at the point of recovery after holding the elongated sample for 30 seconds for the fifth time were plotted and curves were generated. The stress at 200% strain was calculated as (P-200), and the strength within the practical application range of expansion and contraction characteristics at a predetermined fineness (22 dtex) was calculated as (G4).

[0100] The number of measurements was n=3, and the average value was used to calculate the above characteristics.

[0101] (1) Basic properties of elastic fibers

[0102] The basic properties of elastic fibers are breaking strength, breaking elongation, and permanent strain rate, and these were measured.

[0103] ■ Fracture strength (cN) = (G3)

[0104] ■Recovery stress (cN) within the actual application range = (G4)

[0105] ■ Permanent strain rate (%) = 100 x ((L2) - (L1)) / (L1)

[0106] (2) Stability of elastic fibers over time

[0107] The changes in strength and strain rate over time within the actual application range were measured as the stability of the elastic fiber over time. The date of collection of test fibers after spinning was set as day 0. After storage at 21°C and 60% humidity, the physical properties of the test fibers were measured after one day and three months, and the properties were calculated using the following equation.

[0108] ■ Change in fiber strength over time within the actual operating range (%) = [(Fiber strength within the actual operating range three months after spinning) / (Fiber strength within the actual operating range one day after spinning)] x 100

[0109] ■ Change in strain rate over time (%) = [(Permanent strain rate of fiber three months after spinning) / (Permanent strain rate of fiber one day after spinning)] x 100

[0110] Here, the smaller difference in physical property values ​​of polyurethane urea elastic fibers one day and three months after spinning indicates better stability over time. The following criteria were used to evaluate the changes in strength and strain rate over time within the practical application range: 90% or greater and less than 120% indicates particularly excellent stability over time (◎), 85% or greater and less than 90% or 120% or greater and less than 125% indicates excellent stability over time (o), and less than 85% or greater than 125% indicates residual problems with stability over time (x).

[0111] [2] Spinability of elastic fibers

[0112] Spinning was performed continuously for 48 hours, and the number of broken fibers after this time was used as an indicator of spinnability. Fewer than two fiber breaks after 48 hours of continuous spinning were considered excellent (◎). More than two fiber breaks within 48 hours, but fewer than two within 24 hours, were considered good (o).

[0113] [Example 1]

[0114] ■Preparation of spinning solution a

[0115] A DMAc solution (35% by mass) of a polyurethane polymer was prepared in a conventional manner, the DMAc solution using the following as starting materials: PTMG (molecular weight 1,800) as a polymer diol, MDI as a diisocyanate, ethylenediamine as a chain extender, and diethylamine as a capping agent, and the DMAc solution was named A1.

[0116] ■ Preparation of Additive Solution b

[0117] A DMAc solution (35% by mass) of polyurethane (Metachlor 2462 from DuPont) was prepared using the following starting materials: tert-butyldiethanolamine as a diol having a tertiary amine nitrogen and methylenebis(4-cyclohexyl isocyanate) as a diisocyanate, and the DMAc solution was named T1.

[0118] ■ Preparation of Additive Solution C

[0119] A DMAc solution (concentration 35% by mass) of p-toluenesulfonic acid monohydrate (hereinafter PTSA), which is a sulfonic acid compound, was prepared and the DMAc solution was named S1.

[0120] ■ Preparation of additive solution d

[0121] T1 and S1 were thoroughly mixed together at a ratio of 90 wt% and 10 wt%, respectively, and then mixed again at 30 °C under a nitrogen atmosphere for one hour to obtain a DMAc solution (concentration 35 wt%) of a mixture of additive B and unreacted PTSA, wherein the tertiary amine moiety in T1 had been converted to a sulfonate ammonium salt. This solution was subjected to repeated hexane extraction and toluene washing to remove unreacted sulfonate compounds and obtain additive B in solid form. This solid was dissolved in DMAc to prepare a DMAc solution of additive B (concentration 35 wt%), and this solution was named B1.

[0122] ■ Preparation of Additive Solution e

[0123] A DMAc solution (35% by mass) of a condensation polymer of p-cresol and divinylbenzene (from DuPont's Metachlor (registered trademark) 2390) was prepared as another additive, and said other additive was named Z1.

[0124] ■Preparation of spinning solution

[0125] A1, B1, and Z1 were uniformly mixed together at 98.9% by mass, 0.1% by mass, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set to 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0126] [Example 2]

[0127] A1, B1, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0128] [Example 3]

[0129] A1, B1, and Z1 were uniformly mixed at 94%, 5%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0130] [Example 4]

[0131] A1, B1, and Z1 were uniformly mixed together at 89%, 10%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set to 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0132] [Example 5]

[0133] A1, B1, and Z1 were uniformly mixed together at 79%, 20%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set to 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0134] [Example 6]

[0135] A DMAc solution (35% by mass) of 3-[[2-(methacryloyloxy)ethyl]dimethylamino]prop-1-sulfonic acid was prepared as a substitute for S1 in the same manner as in Example 1, and the DMAc solution was named S2. Furthermore, a DMAc solution (35% by mass) of additive B, consisting of T1 and S2, was prepared, and the DMAc solution was named B2.

[0136] A1, B2, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0137] [Example 7]

[0138] A DMAc solution (35% by mass) of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid monohydrate was prepared as a substitute for S1 in the same manner as in Example 1, and the DMAc solution was named S3. Furthermore, a DMAc solution (35% by mass) of additive B, consisting of T1 and S3, was prepared, and the DMAc solution was named B3.

[0139] A1, B3, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0140] [Example 8]

[0141] As an alternative to T1 in Example 1, N,N-dimethylhydrazine was reacted at the end of the structure with an adduct having 6 to 8 repeating units of tert-butyldiethanolamine and methylene bis(4-cyclohexyl isocyanate) to obtain a polymer that forms dimethylaminourea at the end, and this polymer was used to prepare a DMAc solution (concentration 35% by mass), which was named T2.

[0142] A DMAc solution (concentration 35% by mass) of additive B consisting of T2 and S1 was prepared in the same manner as in Example 1, and the DMAc solution was named B4.

[0143] A1, B4 and Z1 were uniformly mixed together at 97% by mass, 2% by mass and 1% by mass, respectively, to obtain a spinning solution. The spinning solution was then dry spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller and the winder set to 1.4, to obtain 100g of spun 22dtex multifilament polyurethane elastic fiber.

[0144] The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0145] [Example 9]

[0146] A DMAc solution (35% by mass) of a polyurethane urethane polymer used as polyurethane A was prepared in a conventional manner. The polyurethane A consisted of PTMG with a molecular weight of 2,100, MDI, ethylene glycol, and 1-butanol as a capping agent.

[0147] A2, B1, and Z1 were uniformly mixed together at 98.9% by mass, 0.1% by mass, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0148] [Example 10]

[0149] A2, B1, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0150] [Example 11]

[0151] A2, B1, and Z1 were uniformly mixed at 94%, 5%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0152] [Example 12]

[0153] A2, B1, and Z1 were uniformly mixed together at 89%, 10%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0154] [Example 13]

[0155] A2, B2, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0156] [Example 14]

[0157] A2, B3, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0158] [Example 15]

[0159] A2, B4, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0160] [Comparison Example 1]

[0161] A1 and Z1 were uniformly mixed at 99% and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0162] [Comparison Example 2]

[0163] A1, T1, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0164] [Comparative Example 3]

[0165] A DMAc solution (35% by mass) of sulfonate ammonium methyl sulfonate was prepared using Neogermi DFS (decyl dimethyl trifluoride ammonium methanesulfonate) from Sanyo Kasei Co., Ltd. as a sulfonate ammonium salt without a polyurethane structure. This solution was used as D2.

[0166] A1, D2, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 520 m / min, with the speed ratio of the guide roller to the winder set at 1.4, to obtain 100 g of spun 22 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0167] [Comparison Example 4]

[0168] A2 and Z1 were uniformly mixed at 99% and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0169] [Comparative Example 5]

[0170] A2, T1, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0171] [Comparison Example 6]

[0172] A2, D2, and Z1 were uniformly mixed at 97%, 2%, and 1% by mass, respectively, to obtain a spinning solution. This spinning solution was then dry-spun and wound at a spinning speed of 540 m / min, with the speed ratio of the guide roller to the winder set to 1.5, to obtain 50 g of spun 20 dtex multifilament polyurethane elastic fiber. The composition of this polyurethane elastic fiber is shown in Table 1, and the properties of this fiber are shown in Table 2.

[0173] In Tables 1 and 2, "polyurethane elastic fiber" is simply referred to as "elastic fiber".

[0174]

[0175]

Claims

1. A polyurethane elastic fiber comprising polyurethane A and additive B: Polyurethane A: A polyurethane that uses polymeric diols, diisocyanates, and chain extenders as starting materials and does not contain tertiary amines in the backbone; Additive B: A polyurethane or polyurea using diols and / or diamines and diisocyanates as starting materials and having tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, wherein the tertiary amine nitrogen is ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine.

2. The polyurethane elastic fiber according to claim 1, wherein additive B is polyurethane or polyurea, and wherein the diol starting material comprises a diol containing a tertiary amine as a major component.

3. The polyurethane elastic fiber according to claim 1 or 2, wherein additive B is polyurethane or polyurea, and wherein the diamine starting material comprises a diamine containing a tertiary amine as a major component.

4. The polyurethane elastic fiber according to claim 1 or 2, wherein the sulfonic acid compound in additive B has a molecular weight of 96 or greater and 300 or less.

5. The polyurethane elastic fiber according to claim 1 or 2, wherein the amount of additive B is 0.1% by weight or more and 10% by weight or less.

6. The polyurethane elastic fiber according to claim 1 or 2, wherein the end group of additive B is N,N-dialkylaminourea.

7. A method for producing polyurethane elastic fibers, the method comprising: Spinning was performed on a spinning solution containing polyurethane A and additive B: Polyurethane A: A polyurethane that uses polymeric diols, diisocyanates, and chain extenders as starting materials and does not contain tertiary amines in the backbone; Additive B: A polyurethane or polyurea using diols and / or diamines and diisocyanates as starting materials and having tertiary amine nitrogen bonded only to non-aromatic carbons in the backbone, wherein the tertiary amine nitrogen is ionicly bonded to a sulfonic acid compound to form a sulfonic acid amine.

8. The method for producing polyurethane elastic fibers according to claim 7, the method comprising: Add the following additive solutions b and c to spinning solution a to obtain a spinning solution containing polyurethane A and additive B. And spinning the spinning solution. Wherein spinning solution a is a spinning solution containing the above-mentioned polyurethane A; Additive solution b is an additive solution containing polyurethane or polyurea, wherein the polyurethane or polyurea uses diol and / or diamine and diisocyanate as starting materials and has tertiary amine nitrogen that bonds only to non-aromatic carbons in the backbone; and Additive solution c is an additive solution containing a sulfonic acid compound with a molecular weight of 96 or greater and 300 or less.

9. The method for producing polyurethane elastic fibers according to claim 7, the method comprising: Additive solution b and additive solution c are mixed together to obtain additive solution d containing additive B, wherein additive B has a sulfonic acid amine salt structure, wherein the tertiary amine and sulfonic acid are ionicly bonded in the molecular structure; spinning solution a and additive solution d are mixed together to obtain spinning solution; and the spinning solution is spun. Wherein spinning solution a is a spinning solution containing the above-mentioned polyurethane A; Additive solution b is an additive solution containing polyurethane or polyurea, wherein the polyurethane or polyurea uses diol and / or diamine and diisocyanate as starting materials and has tertiary amine nitrogen that bonds only to non-aromatic carbons in the backbone; and Additive solution c is an additive solution containing a sulfonic acid compound with a molecular weight of 96 or greater and 300 or less.

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