Polyurethane elastic yarn and process for its production

Abstract

Provided is a polyurethane elastic fiber having excellent antibacterial properties and a production method thereof. The elastic fiber is composed of a polyurethane whose main components are a polymeric diol and a diisocyanate, wherein the polyurethane elastic fiber contains a slowly water-soluble glass containing a Group 1B and / or Group 2B element and a nonionic surfactant.

Description

Technical Field

[0001] This invention relates to a polyurethane elastic fiber with excellent antibacterial properties and excellent resistance to yellowing, a polyurethane elastic fiber suitable for obtaining fabrics with antibacterial properties, and a method for producing the same. Background Technology

[0002] Elastic fibers are used in a wide range of applications due to their excellent elastic properties, including elastic clothing applications such as socks, underwear and sportswear; hygiene applications such as disposable diapers and sanitary napkins (as protective materials); and industrial applications.

[0003] In response to the growing demand for more comfortable living environments, so-called "antimicrobial products" have become popular in recent years. These products include antimicrobial paints, antimicrobial films and sheets, antimicrobial filaments, antimicrobial cosmetics, antimicrobial kitchenware, antimicrobial writing instruments, antimicrobial sand, antimicrobial tissues, antimicrobial fibers, and antimicrobial cosmetics.

[0004] Many different inorganic antimicrobial agents are used as antimicrobial agents in these products, especially silver antimicrobial agents.

[0005] Compared to organic antimicrobial agents, these inorganic antimicrobial agents exhibit better weather resistance and chemical resistance, and lower acute oral toxicity. Furthermore, because inorganic antimicrobial agents have significantly higher heat resistance than organic antimicrobial agents, they have been added to synthetic resins used in many fields.

[0006] Examples of metal ions constituting inorganic antibacterial agents include silver, mercury, copper, zinc, and tin ions. Silver and copper ions are particularly well-known. Excellent antibacterial effects are achieved when these metal ions are supported on materials with porous structures, such as glass, zeolite, silica gel, silicates, whiskers, alumina, and ceramics. Numerous technologies have been proposed for these fibers (Patent Documents 1-3).

[0007] However, when molding synthetic resins containing added inorganic antimicrobial agents, problems arise with the gelation of the synthetic resin and changes in its molecular weight due to the cross-linking and catalytic reactions of the metals in the inorganic antimicrobial agents. Furthermore, the value of the resulting product is significantly reduced due to heat discoloration during molding, discoloration attributed to exposure to NOx gases, and discoloration attributed to exposure to light.

[0008] Therefore, techniques for inhibiting discoloration of antimicrobial resins containing added inorganic antimicrobial agents have been proposed (Patent Document 4). However, while these techniques provide a certain degree of antimicrobial performance, significant yellowing occurs in certain environments and over time, and the problem cannot be considered fully solved.

[0009] [Existing Technical Documents]

[0010] [Patent Documents]

[0011] [Patent Document 1] JP H05-339810A

[0012] [Patent Document 2] JP H06-093565A

[0013] [Patent Document 3] JP 2017-040007 A

[0014] [Patent Document 4] JP 4485871 B2 Summary of the Invention

[0015] [Problems to be solved by this invention]

[0016] One objective of this invention is to provide a polyurethane elastic fiber with excellent antibacterial properties and excellent resistance to yellowing.

[0017] [A method used to solve problems]

[0018] The present invention solves this problem in the following manner.

[0019] (1) A polyurethane elastic fiber whose main component is a polyurethane whose main starting materials are polymeric diol and diisocyanate, wherein the polyurethane elastic fiber comprises (a) a slow-water-soluble glass containing elements of Group 1B and / or Group 2B and (b) a nonionic surfactant.

[0020] (2) The polyurethane elastic fiber according to (1), wherein the amount of (a) is 0.1% by mass or more and 30% by mass or less.

[0021] (3) The polyurethane elastic fiber according to (1) or (2), wherein the average primary particle size of (a) is 3.0 μm or less.

[0022] (4) The polyurethane elastic fiber according to any one of (1) to (3), wherein (a) is a slow-water soluble glass containing silver and / or a slow-water soluble glass containing copper.

[0023] (5) The polyurethane elastic fiber according to any one of (1) to (4), wherein (b) is a polyoxyethylene alkyl ether.

[0024] (6) The polyurethane elastic fiber according to any one of (1) to (5), wherein the polyurethane elastic fiber further comprises a quaternary ammonium salt antimicrobial agent.

[0025] (7) A method for producing polyurethane elastic fibers, the method comprising: mixing (a) a slow-water-soluble glass containing a Group 1B and / or Group 2B element with a spinning solution; mixing the slow-water-soluble glass containing the Group 1B and / or Group 2B element in an amount in the range of 0.01% by mass or more and 20% by mass or less in a nonionic surfactant relative to the (a) slow-water-soluble glass containing the Group 1B and / or Group 2B element; and dry spinning the spinning solution.

[0026] (8) The method for producing polyurethane elastic fibers according to (7), wherein (a) a slow-water-soluble glass containing elements of Group 1B and / or Group 2B is mixed in the form of a dispersion solution with a spinning solution containing polyurethane, wherein the main starting materials of the polyurethane are polymeric diol and diisocyanate.

[0027] (9) The method for producing polyurethane elastic fibers according to (7) or (8), wherein the (a) Group 1B and / or Group 2B element is silver and / or copper.

[0028] (10) A method for producing polyurethane elastic fibers according to any one of (7) to (9), wherein (b) is a polyoxyethylene alkyl ether.

[0029] [Function of the Invention]

[0030] This invention enables the production of polyurethane elastic fibers with excellent antibacterial properties, colorfastness, and elasticity. The main component is polyurethane, whose primary starting materials are polymeric glycol and diisocyanate. The polyurethane elastic fibers contain (a) a slowly water-soluble glass and nonionic surfactant containing elements from Group 1B and / or Group 2B. Fabrics using this polyurethane elastic fiber exhibit excellent antibacterial properties, colorfastness, and elasticity. Detailed Implementation

[0031] The present invention will now be described in detail.

[0032] The polyurethane used as the main component of polyurethane elastic fibers will be described first. Here, "main component" means the component that constitutes more than 50% by mass of the polyurethane elastic fibers.

[0033] There are no specific limitations on the polyurethane used in this invention. It can be any polyurethane, as long as it has a structure in which the main starting materials are polymeric diol and diisocyanate. Here, polymeric diol and diisocyanate as starting materials means that the resulting polyurethane polymer has a structure derived from these components. In this specification, the structure of the polyurethane polymer obtained by using polymeric diol and diisocyanate as starting materials is specified. Equivalent structures can be formed from different raw materials, and the raw materials themselves are not specified. There are also no specific limitations on the synthesis method used. For example, it can be a polyurethane urea composed of polymeric diol, diisocyanate and low molecular weight diamine acting as a chain extender, or it can be a polyurethane urethane composed of polymeric diol, diisocyanate and low molecular weight diol acting as a chain extender. It can also be a polyurethane urea using compounds having hydroxyl and amino groups in the molecule as chain extenders. Polyfunctional diols and isocyanates with trifunctionality or higher can also be used, as long as the effect of the invention is not diminished. Here, polyurethane with polymeric glycols and diisocyanates as the primary starting materials means that more than 50% by mass of the isocyanate compound in the starting materials is diisocyanate, and more than 50% by mass of the component in the starting materials that reacts with the isocyanate compound (polymeric glycol, low molecular weight diamine, low molecular weight glycol, compounds with hydroxyl and amino groups in the molecule, polyfunctional glycols, etc.) is polymeric glycol. When calculating the mass ratio, it is assumed that these components are used as starting materials, regardless of the actual raw materials used. In glycol compounds, low molecular weight glycols mean compounds with a molecular weight less than 500, and glycol compounds with a molecular weight of 500 or greater are called polymeric glycols (the same applies to diamine compounds).

[0034] The polymer glycol is preferably a polyether glycol, a polyester glycol, or a polycarbonate glycol. From the viewpoint of imparting flexibility and elasticity to the fabric, polyether glycol is preferred.

[0035] Preferred examples of polyether glycols include polyethylene oxide, polyethylene glycol, polyethylene glycol derivatives, polypropylene glycol, polytetramethylene ether glycol (PTMG), modified PTMG as a copolymer of tetrahydrofuran (THF) and 3-methyltetrahydrofuran, modified PTMG as a copolymer of tetrahydrofuran (THF) and 2-dimethyltetrahydrofuran, modified PTMG as a copolymer of THF and 2,3-dimethylTHF, polyols having side chains on both sides as disclosed in JP 2615131 B2, and random copolymers of THF and ethylene oxide and / or propylene oxide in an irregular arrangement. One or more of these polyether glycols can be blended or copolymerized together and then used.

[0036] From the viewpoint of obtaining polyurethane elastic fibers with abrasion resistance and light resistance, preferred examples include butyl adipic acid, polycaprolactone diol, polyester diol (such as polyester polyols with side chains disclosed in JP S61-026612 A) and polycarbonate diol disclosed in JP H02-289516 A.

[0037] These polymer diols can be used alone, or two or more can be mixed together or copolymerized and then used.

[0038] From the viewpoint of obtaining elasticity, strength, and heat resistance when making fibers, the polymer diol used in this invention preferably has a molecular weight of 1,000 or more and 8,000 or less, and more preferably 1,500 or more and 6,000 or less. When using polyols with molecular weights within this range, elastic fibers with excellent elasticity, strength, elastic resilience, and heat resistance can be readily obtained.

[0039] The aromatic diisocyanates used in this invention 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), isophorone diisocyanate, methylcyclohexane 2,4-diisocyanate, methylcyclohexane 2,6-diisocyanate, cyclohexane 1,4-diisocyanate, hexahydroxylene diisocyanate, hexahydrotoluene diisocyanate, and octahydro-1,5-naphthalene diisocyanate. Aliphatic diisocyanates are particularly effective in inhibiting yellowing of polyurethane elastic fibers. These diisocyanates can be used alone or in combinations of two or more.

[0040] The chain extender used in this invention is preferably at least one of a low molecular weight diamine and a low molecular weight diol. The molecule may also have hydroxyl and amino groups, such as ethanolamine.

[0041] Preferred examples of low molecular weight diamines include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, hexanediamine, p-phenylenediamine, p-xylenediamine, m-xylenediamine, p,p'-methylenediphenylamine, 1,3-cyclohexyldiamine, hexahydromethphenylenediamine, 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.

[0042] Typical examples of low molecular weight diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, dihydroxyethoxybenzene, polyethylene terephthalate, and 1-methyl-1,2-ethylene glycol. These can be used alone or in combination of two or more. 1,3-propylene glycol and 1,4-butanediol are particularly preferred. When used, diol-extended polyurethanes exhibit higher heat resistance and yield stronger fibers.

[0043] From the viewpoint of obtaining fibers with high durability and strength, the number-average molecular weight of the polyurethane urea polymers used in this invention is preferably in the range of 30,000 or more and 150,000 or less. Molecular weight is measured by GPC and converted in relation to polystyrene.

[0044] One or more end-blocking agents are preferably incorporated into the polyurethane elastic fibers of the present invention. Preferred examples of end-blocking 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.

[0045] In this invention, polyurethane elastic fibers composed of polyurethane having the basic configuration described above can maintain excellent antibacterial properties by including (a) a slowly water-soluble glass containing Group 1B elements and / or Group 2B elements and a nonionic surfactant. The slowly water-soluble glass is a silicate glass that is generally insoluble in water, i.e., a glass produced by blending a total of 30% by mass or more of P2O5 and / or B2O3 with SiO2 as the main raw material, which slowly dissolves in water. The slowly water-soluble glass used in this invention only needs to be able to retain (a) Group 1B elements and / or Group 2B elements. Besides general slowly water-soluble glasses using SiO2 as the main raw material, it can be composed of self-vitrifying P2O5 and / or B2O3 as the main raw material and does not contain any SiO2 at all. When less than 30% by mass of P2O5 and / or B2O3 and SiO2 are present in the slow-water soluble glass of (a) the present invention, the elution of Group 1B and / or Group 2B element ions during water-based treatment steps (such as dyeing steps) for polyurethane elastic fibers becomes unsuccessful, and the antibacterial effect is insufficient.

[0046] In this invention, (a) the Group 1B and / or Group 2B elements in the slow-water-soluble glass are preferably added as oxides in the form of raw materials. Examples of oxides of (a) the Group 1B and / or Group 2B elements include AgO, Ag2O, Ag2O3, CuO, Cu2O, ZnO, and Al2O3. From the viewpoint of antibacterial properties, the oxidation number of (a) the Group 1B and / or Group 2B elements is preferably as low as possible while providing a stable material, and the oxides are more preferably Ag2O or CuO. Preferably, the oxides of (a) the Group 1B and / or Group 2B elements are incorporated into the slow-water-soluble glass powder of phosphate and / or borate based on the raw material amount of 1% by mass or more.

[0047] Antibacterial polyurethane elastic fibers can be produced using various methods from phosphoric acid-based slow-water-soluble glasses and / or borate-based (a) slow-water-soluble glasses containing Group 1B elements and / or Group 2B elements. These (a) slow-water-soluble glasses containing Group 1B elements and / or Group 2B elements can be used alone or in mixtures of two or more. There are no specific limitations on the methods used to produce slow-water-soluble glasses, but melt-quenching or sol-gel methods are preferred. In addition to the components described above, trace amounts of SrO, BaO, TiO2, ZrO2, Nb2O5, Cs2O, Rb2O, TeO2, BeO, GeO2, Bi2O3, La2O3, Y2O3, WO3, MoO3, or Fe2O3 can be included in the glass solid solution during the production of slow-water-soluble glasses. Furthermore, F, Cl, SO3, Sb2O3, SnO2, or Ce can be added as clarifying agents.

[0048] Relative to the total mass of polyurethane elastic fibers, (a) the amount of slowly water-soluble glass containing Group 1B and / or Group 2B elements is preferably in the range of 0.1% by mass or more to 30% by mass or less. When the amount of slowly water-soluble glass containing Group 1B and / or Group 2B elements is less than 0.1% by mass, it is sometimes difficult to obtain sufficient antimicrobial properties when used as fabric. More preferably, the amount is 0.5% by mass or more. When the amount exceeds 30% by mass, it may cause deterioration of elastic properties and is disadvantageous in terms of cost. The amount is preferably 10% by mass or less, and more preferably 5.0% by mass or less. From the viewpoint of balancing antimicrobial properties and physical properties with cost, the range is more preferably 1.0% by mass or more to 5.0% by mass or less.

[0049] In this invention, from the viewpoint of suppressing clogging of the spinning solution in the spinning head, (a) the average primary particle size of the slowly water-soluble glass containing Group 1B and / or Group 2B elements is preferably 3.0 μm or less. More preferably, it is 1.5 μm or less. From the viewpoint of dispersibility, when the average primary particle size is less than 0.05 μm, cohesion increases and it is difficult to uniformly mix the spinning solution. Therefore, an average primary particle size of 0.05 μm or greater is preferred. More preferably, it is 0.15 μm or greater. The average primary particle size is determined using an electron microscope. For example, an equivalent of the projected area circle for the primary particles is generated in a certain direction in the interval between two parallel lines by image processing, which insert the primary particles into a field of view magnified tens of thousands of times. Twenty diameters are randomly measured, and the upper limit 5% (maximum value) and lower limit 5% (minimum value) are removed based on a number standard, and the average value of the remaining 90% (values ​​of 18 particles) is calculated. The particle size distribution is preferably obtained by dividing the average primary particle size by the most frequent particle size (mode diameter) of 0.5 to 1.5, and more preferably 0.8 to 1.2. Preferably, the maximum particle size distribution is within 2.0 times the average primary particle size, and more preferably 1.5 times or less.

[0050] In this invention, (a) a slowly water-soluble glass containing Group 1B and / or Group 2B elements is preferably uniformly distributed in polyurethane. Various known surfactants can be used as dispersants for dispersing the glass. However, it has been found that nonionic surfactants are used to uniformly disperse (a) a slowly water-soluble glass containing Group 1B and / or Group 2B elements in polyurethane to obtain polyurethane elastic fibers with excellent spinnability, antimicrobial properties, colorfastness, and elasticity. The use of nonionic surfactants has also been found to have a synergistic effect, especially for antimicrobial properties. Meanwhile, ionic surfactants (such as anionic surfactants, cationic surfactants, and anionic-cationic amphoteric surfactants) typically do not exhibit antimicrobial properties after undergoing water-based treatment steps (such as dyeing) required for the fabric.

[0051] Examples of nonionic surfactants that can be used in this invention include polyoxyethylene alkyl ethers, alkyl monoglyceride ethers, polyoxyethylene alkylamines, fatty acid dehydrated sorbitol esters, and fatty acid diethanolamides. The so-called hydrophilic portion (hydrophilic part) of the surfactant is preferably an ether, and more preferably at least one of ethylene oxide polymers, propylene oxide polymers, and ethylene oxide / propylene oxide copolymers. By using at least one of the end-modified derivatives of ethylene oxide polymers, end-modified derivatives of propylene oxide polymers, and end-modified derivatives of ethylene oxide / propylene oxide copolymers as nonionic surfactants, antibacterial properties can be improved while simultaneously enhancing spinnability. The so-called hydrophobic portion (hydrophobic part) of the surfactant can be one of the end-modified structures mentioned above. However, alkyl, phenyl, and styrene-modified phenyl groups are preferred. Specific examples of nonionic surfactants include polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene ethyl phenol ether, polyoxyethylene propyl phenol ether, polyoxyethylene styrene phenyl ether, and polyoxyethylene sorbitan tetraoleate. Particularly preferred are polyoxyethylene styrene phenyl ethers, such as polyoxyethylene oxypropylene tristyrene phenyl ether, polyoxyethylene oxypropylene bistyrene phenyl ether, polyoxyethylene oxypropylene monostyrene phenyl ether, polyoxyethylene oxypropylene-2,4,6-tris(a,a-dimethylbenzyl)phenyl ether, polyoxyethylene oxypropylene-2,4-bis(a,a-dimethylbenzyl)phenyl ether, polyoxyethylene oxypropylene-2-mono(a,a-dimethylbenzyl)phenyl ether, and polyoxyethylene oxypropylene-4-mono(a,a-dimethylbenzyl)phenyl ether. Most preferably, mixtures in which the molar number of these styrene groups is distributed are preferred.

[0052] In this invention, quaternary ammonium salt antimicrobial agents are also preferably used. It is important to maintain appropriate antimicrobial levels of skin sensitivity, especially in textile structures of clothing, medical fabrics, and protective materials. Even though slow-soluble glass containing Group 1B and / or Group 2B elements is completely inorganic, organic quaternary ammonium salt antimicrobial agents readily distribute on the surface layer of polyurethane elastic fibers. Because the elution of quaternary ammonium occurs more rapidly, the initial antimicrobial properties of quaternary ammonium salt antimicrobial agents can be easily controlled immediately after production or immediately after fabric treatment (such as dyeing). Because the elution of Group 1B and / or Group 2B elements in slow-soluble glass containing Group 1B and / or Group 2B elements occurs more slowly, the desired level of antimicrobial properties can be maintained even after repeated washing and long-term aging by adjusting (e.g.) the amount and particle size added. In this way, by using antimicrobial agents with different elution rates as the antimicrobial component in polyurethane elastic fibers, antimicrobial properties can be designed to remain at an optimal level after long-term aging, similar to their initial state. When quaternary ammonium salt antimicrobial agents are also used, the antimicrobial activity varies depending on the chain length of the alkyl group in the ammonium ion, and strong antimicrobial activity is preferred. However, from the viewpoint of suppressing thermal decomposition caused by heat during the production of polyurethane elastic fibers, and from the viewpoint of suppressing the ionization of (a) Group 1B elements and / or Group 2B elements in slowly water-soluble glasses, chain type (such as alkyl) and alkyl groups with long chain lengths (i.e., alkyl groups with a large number of carbon atoms) are preferred. From this viewpoint, dialcyldimethylammonium ion and oleyltrimethylammonium ion are particularly preferred. Counterions constituting quaternary ammonium salts should also be considered. These are generally supplied by inorganic salts (such as chlorides, bromides, and iodides) and organic acid salts (such as carboxylates, sulfonates, and phosphates). From the viewpoint of stability regarding discoloration and heat resistance, as well as improvement in breaking strength and elongation, carboxylates and sulfonates are preferred, with carboxylates being the most preferred.

[0053] Specific examples of salts having this structure include dialcyldimethylammonium carboxylates, such as dialcyldimethylammonium adipate, dialcyldimethylammonium gluconate, and dialcyldimethylammonium propionate; oleyltrimethylammonium carboxylates, such as oleyltrimethylammonium adipate and oleyltrimethylammonium gluconate; and sulfonates, such as dialcyldimethylammonium trifluoromethanesulfonate, di-n-decyldimethylammonium trifluoromethanesulfonate, di-n-decyldimethylammonium pentafluoroethanesulfonate, n-hexadecyltrimethylammonium trifluoromethanesulfonate, and benzyldimethylcocoyl alkylammonium pentafluoroethanesulfonate.

[0054] From the viewpoint of exhibiting antibacterial properties while maintaining a good balance between discoloration and elasticity, the amount of quaternary ammonium salt antibacterial agent relative to the total mass of polyurethane elastic fibers is preferably in the range of 0.1% by mass or more and 5% by mass or less. 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 Sumilyzer GA-80 (registered trademark) from Sumitomo Chemical Co., Ltd.; benzotriazole and benzophenone reagents, such as Tinuvin (registered trademark) from Ciba Geigy Co., Ltd.; phosphorus reagents, such as Sumilyzer P-16 (registered trademark) from Sumitomo Chemical Co., Ltd.; hindered amines; pigments, such as iron oxide and titanium oxide; minerals, such as hydrotalcite compounds, calcium carbide, magnesia, and tourmaline; inorganic materials, such as zinc oxide, cerium oxide, magnesium oxide, calcium carbonate, and carbon black; fluorinated or silicone resin powders; metallic soaps, such as magnesium stearate; bactericides and deodorants (containing silver, zinc, or compounds thereof); lubricants, such as silicones and mineral oils; and antistatic agents, such as cerium oxide, betaine, and phosphoric acid. These are preferably reacted with polymers. To improve durability against light and various types of nitrogen oxides, nitrogen oxide supplements such as HN-150 from Nippon Hydrazine 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.

[0055] The method for producing the polyurethane elastic fibers of the present invention will now be explained in detail.

[0056] In this invention, polymeric glycols and diisocyanates are used as the main starting materials, and the polyurethane spinning solution obtained from these via dry spinning contains (a) a slowly water-soluble glass comprising Group 1B elements and / or Group 2B elements and a nonionic surfactant. The slowly water-soluble glass comprising Group 1B elements and / or Group 2B elements is mixed with the nonionic surfactant. When preparing the polyurethane spinning solution, the nonionic surfactant is incorporated in a range of 0.01 parts by mass or more and 20 parts by mass or less of (a) the slowly water-soluble glass comprising Group 1B elements and / or Group 2B elements, at a ratio of 100 parts by mass. More preferably, the nonionic surfactant is pre-kneaded into the fine powder obtained in the following steps, wherein the slowly water-soluble glass comprising Group 1B elements and / or Group 2B elements is pulverized to coat the fine powder with the nonionic surfactant. Polyurethane solutions or polyurethane in solute form in solution can be prepared using melt polymerization, solution polymerization, or some other methods. However, solution polymerization is particularly preferred. In solution polymerization, few foreign substances (such as gels) are generated in polyurethane, making it easier to spin the spinning solution and obtain polyurethane elastic fibers with low fineness. Of course, solution polymerization is also advantageous because the solution preparation step can be omitted.

[0057] The polyurethanes particularly suitable for this invention are synthesized using PTMG as a polymeric diol with an average molecular weight of 1,500 or more and 6,000 or less, MDI as a diisocyanate, and at least one of ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, and hexamethylenediamine as chain extenders.

[0058] Polyurethane can be obtained by synthesizing the raw materials described above, such as dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), n-methylpyrrolidone (NMP), or solvents containing these as major components. Preferred methods include the so-called one-shot method, in which the raw materials are added to a solvent, dissolved, heated to a suitable temperature, and reacted to form polyurethane; and methods in which a polymeric diol and a diisocyanate are melt-reacted, and the reaction product is dissolved in a solvent and reacted with a chain extender to obtain polyurethane.

[0059] When glycols are used as chain extenders, from the viewpoint of obtaining excellent heat resistance, it is preferable to adjust the melting point of the polyurethane on the higher side to a range of 200°C or higher and 260°C or lower. 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.

[0060] When the molecular weight of the polymeric diol is 1,800 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 on the higher side to 200°C or higher.

[0061] In synthesizing these polyurethanes, it is preferable to use one type of catalyst (such as amine catalysts and organometallic catalysts) or a mixture of two or more types of catalysts.

[0062] 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'-pentamethyldiethylenetriamine, tetramethylguanidine, trimethylamine, etc. Ethyldiamine, 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.

[0063] Examples of organometallic catalysts include tin octoate, dibutyltin dilaurate, and dibutyl lead octoate.

[0064] The concentration of polyurethane urea polymer in the resulting polyurethane polymer solution is preferably in the range of 30% by mass or more and 80% by mass or less.

[0065] In this invention, (a) a slow-release, water-soluble glass and nonionic surfactant containing an element of Group 1B and / or Group 2B is added to the polyurethane solution. Any method may be used to add (a) the slow-release, water-soluble glass and nonionic surfactant containing an element of Group 1B and / or Group 2B to the polyurethane solution. Examples include using a static mixer, stirring, using a homogeneous mixer, and using a biaxial extruder.

[0066] In this invention, to improve antibacterial properties, a slow-water-soluble glass containing Group 1B and / or Group 2B elements is added to the polyurethane elastic fibers in an amount ranging from 0.5% by mass or more to 10% by mass or less. Therefore, the slow-water-soluble glass containing Group 1B and / or Group 2B elements must be uniformly dispersed in the polyurethane spinning solution in an amount ranging from 0.5% by mass or more to 10% by mass or less prior to spinning. Preferably, the slow-water-soluble glass containing Group 1B and / or Group 2B elements and a nonionic surfactant are added to the polyurethane spinning solution using solvents such as N,N-dimethylformamide or N,N-dimethylacetamide, and then mixed under stirring to uniformly disperse the components. More preferably, a slow-water-soluble glass containing Group 1B and / or Group 2B elements and a nonionic surfactant are pre-dispersed in N,N-dimethylformamide or N,N-dimethylacetamide solvent to obtain a dispersion of the slow-water-soluble glass containing Group 1B and / or Group 2B elements, and this dispersion is then mixed into a polyurethane spinning solution. Here, from the viewpoint of uniformly adding the dispersion to the polyurethane solution, the solvent added to the dispersion of the slow-water-soluble glass containing Group 1B and / or Group 2B elements is preferably the same solvent used in the polyurethane solution. Pigments and chemical reagents, such as lightfastness agents and antioxidants, may also be added simultaneously with adding the slow-water-soluble glass containing Group 1B and / or Group 2B elements to the polyurethane solution. Furthermore, from the viewpoint of exhibiting antibacterial properties, the dispersion is prepared in advance by mixing the slow-water-soluble glass containing Group 1B and / or Group 2B elements with a nonionic surfactant, and then added to the polyurethane spinning solution.

[0067] The present invention also preferably contains a quaternary ammonium salt antimicrobial agent to enhance antimicrobial properties against various bacteria. Here, the quaternary ammonium salt antimicrobial agent is added to the polyurethane spinning solution prior to spinning. The quaternary ammonium salt antimicrobial agent can be simply mixed into the polyurethane spinning solution or can be pre-mixed into (a) a dispersion solution of a slowly water-soluble glass containing Group 1B and / or Group 2B elements and a nonionic surfactant. Preferably, the mixing sequence is as follows: the slowly water-soluble glass containing Group 1B and / or Group 2B elements is mixed with a nonionic surfactant to produce a dispersion solution, the quaternary ammonium salt antimicrobial agent is mixed into the dispersion solution, and then the dispersion solution is mixed into the polyurethane spinning solution. Most preferably, the quaternary ammonium salt antimicrobial agent is included in the spinning solution by simply mixing the quaternary ammonium salt antimicrobial agent with a spinning solution separate from the dispersion solution, the dispersion solution being pre-obtained by mixing the slowly water-soluble glass containing Group 1B and / or Group 2B elements with a nonionic surfactant.

[0068] The polyurethane fibers of the present invention can be obtained by, for example, dry spinning, wet spinning, or melt spinning of the undiluted spinning solution described above, followed by winding the fibers. From the viewpoint of stable spinning at all finenesses from thin to thick, dry spinning is particularly preferred.

[0069] There are no specific limitations on the fineness or cross-sectional profile of the polyurethane elastic fibers of the present invention. For example, the cross-sectional profile of the fibers may be circular or flat.

[0070] There are no specific restrictions on dry spinning methods, and spinning can be carried out after selecting appropriate spinning conditions and spinning equipment for the desired characteristics.

[0071] For example, because the permanent strain rate and stress relaxation of the polyurethane elastic fibers of the present invention are particularly susceptible to 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 elastic fibers with the desired permanent strain rate and stress relaxation, it is preferable to take up the fibers at a speed ratio between the guide roller and the winding machine in the range of 1.10 or greater and 1.65 or less.

[0072] Furthermore, from the viewpoint of improving the strength of the resulting polyurethane elastic fibers, the spinning speed is preferably 250 m / min or greater.

[0073] [Example]

[0074] The invention will now be described in more detail with reference to examples, but the invention is not limited to these examples.

[0075] [NOx Anti-yellowing Properties]

[0076] Sample cards were prepared by winding 10g of polyurethane elastic fiber onto a stainless steel plate. This sample was exposed to a gas mixture consisting of air and a specified concentration (7ppm) of NO2 for 50 hours using a Scott colorimeter. The "b" color was measured before and after this exposure using a colorimeter (D25 DP-9000 signal processor), and the degree of yellowing was expressed as the difference "Δb" between the two exposures. The measurements used are the average of n=3.

[0077] [Average primary grain size]

[0078] Inorganic particles were imaged using an S-800 electrolytic radiation scanning electron microscope (FE-SEM) from Hitachi, Ltd., and analyzed using Image-Pro version 4.0 image processing software. Measurement parameters were determined by averaging the diameter equivalent of the projected area circles for each sample (n=20).

[0079] [Spinnability / Fiber Breaking Frequency]

[0080] In terms of fiber breakage frequency / t, the frequency of fiber breakage is measured relative to the solid content of the spinning solution.

[0081] [Preparation of slowly water-soluble glasses containing Group 1B and / or Group 2B elements]

[0082] First, 24 mol% SiO2, 52 mol% B2O3, 10 mol% Na2O, 10 mol% TiO2, and 4 mol% Ag2O were mixed together and melted at 800°C to 1300°C. After cooling, the resulting glass was pulverized, sorted to an average primary particle size of 10 μm or less, and wet-milled to an average primary particle diameter of 0.8 μm to obtain a white powder. This is a slowly water-soluble silver glass 1.

[0083] In addition, 48 mol% P₂O₅, 48 mol% MgO, and 4 mol% Ag₂O were mixed together and melted at 800°C to 1300°C. After cooling, the resulting glass was pulverized, sorted to an average primary particle size of 10 μm or less, and wet-milled to an average primary particle diameter of 0.8 μm to obtain a white powder. This is slow-water-soluble silver glass 2.

[0084] [Preparation of knitted fabrics for evaluation purposes]

[0085] First, the 22-dtex polyurethane elastic fiber is stretched three times and then wrapped with polyamide-processed fiber (Quup 33-dtex / 26 filament from Toray Industries) at a twist rate of 800 T / m to produce S-twist and Z-twist single-covered yarns (SCY).

[0086] S-twist SCY is supplied to yarn feeders 1 and 3 of a pantyhose knitting machine (from Lonati, 400 needles) under a knitting tension of 1.0g, and Z-twist SCY is supplied to yarn feeders 2 and 4 to produce a knitted fabric. The knitted fabric has a polyurethane elastic fiber content of 16%.

[0087] Next, the following steps are performed to dye the knitted fabric and obtain the knitted fabric for tights.

[0088] (1) Preset: Use a vacuum dryer at 90℃ for 10 minutes.

[0089] (2) Dyeing: The knitted fabric was dyed black at 90°C for 60 minutes using 2.0 owf% Lanaset (registered trademark) black B dye from Ciba Specialty Chemicals. pH adjustment during the dyeing process was performed using acetic acid and ammonium sulfate.

[0090] (3) Finally, soften and surface treat by setting process (using pantyhose setting machine, setting: 115℃×10 seconds, drying: 120℃×30 seconds).

[0091] [Washing Instructions]

[0092] This method is performed according to Washing Method Manual (Appendix 1, Washing Method 103 in JIS L0217:2020) of the Japan Textile Evaluation Technology Council. Using a household electric washing machine specified in Washing Method 103, 40 ml of JAFET standard detergent (from the Japan Textile Evaluation Technology Council) is dissolved in 30 liters of water at 40°C to produce a liquid detergent, and 1 kg of laundry sample is added to this liquid detergent. The laundry sample is washed using the following process, wherein a single cycle consists of the following steps: wash for five minutes, spin dry, rinse for two minutes, spin dry, rinse for two minutes, and spin dry again.

[0093] [Antibacterial properties]

[0094] Antimicrobial testing was conducted according to the antimicrobial testing procedure (JIS L1902:2015, Bacterial Solution Absorption Method) specified by the Japan Textile Evaluation Technical Committee. Antimicrobial activity was calculated and evaluated using X as the viable cell count in the untreated test sample after 18 hours of incubation and Y as the viable cell count in the treated test sample after 18 hours of incubation. The measured values ​​are the average of n=3. According to the Japan Textile Evaluation Technical Committee, antimicrobial activity is considered effective when the antimicrobial activity value against Staphylococcus aureus is 2.2 or higher.

[0095] [Strength, stress relaxation rate, permanent strain rate, and elasticity of polyurethane elastic fibers]

[0096] To measure the strength, stress relaxation rate, permanent strain rate, and elasticity of polyurethane elastic fibers, tensile tests were performed on the sample fibers using an Instron 4502 tensile testing machine.

[0097] These tests are defined as follows.

[0098] First, a 5 cm (L1) sample was stretched five times at a tensile rate of 50 cm / min, each time by 300%. The stress during the fifth stretch was defined as (G1). The sample length was then held at 300% elongation for 30 seconds. The stress after holding for 30 seconds was defined as (G2). Next, the sample length was defined as (L2) when the sample recovered its elongated shape and the stress reached zero. The sample was then stretched a sixth time until it fractured. The fracture stress was defined as (G3), and the sample length at fracture was defined as (L3).

[0099] These characteristics are represented by the following equation.

[0100] Fracture strength [cN] = (G3)

[0101] Stress relaxation rate [%] = 100 × ((G1) - (G2)) / (G1)

[0102] Permanent strain rate [%] = 100 × ((L2) - (L1)) / (L1)

[0103] Elasticity [%] = 100 × ((L3) - (L1)) / (L1)

[0104] Perform the tensile test three times and use the average value.

[0105] [Example 1]

[0106] PTMG and MDI with a molecular weight of 1,800 were reacted at 90°C in a molar ratio of 1:1.58 for two hours to obtain an isocyanate-terminated prepolymer. 35% by mass of the isocyanate-terminated prepolymer was dissolved in DMAc to obtain a prepolymer solution. Ethylenediamine and 1,2-propanediamine, acting as chain extenders, and diethylamine, acting as a chain terminator, were mixed together in a mass ratio of 5:1:1, and 35% by mass of the mixture was dissolved in DMAc to obtain an amine solution.

[0107] The prepolymer solution and amine solution were mixed together with stirring at a molar ratio of isocyanate end groups to amine end groups of 1:1.02 to prepare a DMAC solution (35% by mass) of polyurethane urea polymer. Next, a tert-butyl diethanolamine antioxidant (DuPont Metachlor 2462) having methylene-bis-(4-cyclohexyl isocyanate) was mixed with a condensation polymer of p-cresol and divinylbenzene (DuPont Metachlor 2390) at a ratio of 2:1 (by mass) to prepare an antioxidant DMAc solution (35% by mass). Then, 96 parts by mass of the polyurethane urea polymer DMAc solution and 4 parts by mass of the antioxidant solution were mixed together to obtain polymer solution A1. Next, a slow-water-soluble silver glass 1, acting as a slow-water-soluble glass containing elements of Group 1B and / or Group 2B, and a polyoxyethylene alkyl ether (Ionet MO from Sanyo Chemical Industries) acting as a nonionic surfactant, were dispersed in DMAc to obtain dispersion solution B1 (35% by mass). Then, polymer solutions A1 and B1 were uniformly mixed together at 97% by mass and 2% by mass, respectively, to prepare spinning solution D1. This solution was dry-spun at a speed of 720 m / min with a speed ratio of 1.3 between the guide roller and the winding machine to obtain 200 g wound 22 dtex / 2 filament polyurethane elastic yarn containing 2% by mass of the slow-water-soluble glass antibacterial agent and 0.1% by mass of the nonionic surfactant.

[0108] The spinnability, NOx yellowing resistance, and elasticity characteristics of the obtained polyurethane fibers were measured. Knitted fabrics were produced for evaluation purposes, and their antimicrobial properties were measured. The results of these evaluations are shown in Tables 1 and 2.

[0109] [Example 2] to [Example 8]

[0110] Polyurethane elastic fibers were obtained from compositions consisting of the antimicrobial and surfactant components shown in Table 1 using the same method as in Example 1. The spinnability, NOx yellowing resistance, and elasticity characteristics of the resulting polyurethane fibers were measured. Knitted fabrics were produced for evaluation purposes, and the antimicrobial properties of the knitted fabrics were measured. The results of these evaluations are shown in Tables 1 and 2.

[0111] [Example 9] and [Example 10]

[0112] Polyurethane elastic fibers were obtained from a composition consisting of the antimicrobial component, surfactant component, and quaternary ammonium salt antimicrobial agent shown in Table 1, using the same method as in Example 1. After mixing polymer solution A1 with a dispersion containing slow-soluble silver glass 1 and a nonionic surfactant, the quaternary ammonium salt antimicrobial agent was added and dissolved to obtain a spinning solution. The spinnability, NOx yellowing resistance, and elasticity characteristics of the resulting polyurethane fibers were measured. Knitted fabrics were produced for evaluation purposes, and the antimicrobial properties of the knitted fabrics were measured. The results of these evaluations are shown in Tables 1 and 2.

[0113] [Comparison Example 1]

[0114] Polymer solution A1 was dry-spun in the same manner as in Example 1 to obtain 200 g of 22 dtex double filament polyurethane yarn. The spinnability, NOx yellowing resistance, and elasticity characteristics of the resulting polyurethane fibers were measured. Knitted fabrics were produced for evaluation purposes, and the antimicrobial properties of the knitted fabrics were measured. The results of these evaluations are shown in Tables 1 and 2.

[0115] [Comparison Example 2] to [Comparison Example 8]

[0116] Polyurethane elastic fibers were obtained from compositions consisting of the antimicrobial and surfactant components shown in Table 1 using the same method as in Example 1. The spinnability, NOx yellowing resistance, and elasticity characteristics of the resulting polyurethane fibers were measured. Knitted fabrics were produced for evaluation purposes, and the antimicrobial properties of the knitted fabrics were measured. The results of these evaluations are shown in Tables 1 and 2.

[0117] [Table 1]

[0118]

[0119]

[0120] Table 1 continues (a)

[0121]

[0122] Table 1 continues (b)

[0123]

[0124] Table 1 continues (c)

[0125]

[0126] [Table 2]

[0127]

Claims

1. A polyurethane elastic fiber, the main component of which is polyurethane with polymeric diol and diisocyanate as the main starting materials, wherein the polyurethane elastic fiber comprises: (a) a slowly water-soluble glass containing elements of Group 1B and / or Group 2B, and (b) a nonionic surfactant. The amount of (a) is at least 0.1% by mass and at most 10% by mass; The slowly water-soluble glass is a silicate glass produced by doping a total of at least 30% by mass of P2O5 and / or B2O3 with SiO2; or the slowly water-soluble glass is composed of P2O5 and / or B2O3 and contains no SiO2; and The nonionic surfactants mentioned therein include polyoxyethylene alkyl ethers, alkyl monoglyceride ethers, polyoxyethylene alkylamines, fatty acid dehydrated sorbitol esters, and fatty acid diethanolamides.

2. The polyurethane elastic fiber according to claim 1, wherein the amount of (a) is from at least 1% by mass to at most 5% by mass.

3. The polyurethane elastic fiber according to claim 1 or 2, wherein (a) has an average primary particle size of 3.0 μm or less.

4. The polyurethane elastic fiber according to claim 1 or 2, wherein (a) is a slow-water-soluble glass containing silver and / or a slow-water-soluble glass containing copper.

5. The polyurethane elastic fiber according to claim 1 or 2, wherein (b) is a polyoxyethylene alkyl ether.

6. The polyurethane elastic fiber according to claim 1 or 2, wherein the polyurethane elastic fiber further comprises a quaternary ammonium salt antibacterial agent.

7. A method for producing polyurethane elastic fibers according to any one of claims 1-6, the method comprising: mixing a slowly water-soluble glass containing a Group 1B and / or Group 2B element with a spinning solution; mixing 100 parts by weight of the slowly water-soluble glass containing a Group 1B and / or Group 2B element in an amount ranging from at least 0.01 parts by weight to at most 20 parts by weight in a nonionic surfactant; and dry spinning the spinning solution.

8. The method for producing polyurethane elastic fibers according to claim 7, wherein a slowly water-soluble glass containing elements of Group 1B and / or Group 2B is mixed in a dispersion solution with a spinning solution containing polyurethane, wherein the main starting materials of the polyurethane are polymeric diol and diisocyanate.

9. The method for producing polyurethane elastic fibers according to claim 7 or 8, wherein the Group 1B and / or Group 2B elements are silver and / or copper.

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