Spandex filament with skin-core structure and preparation method and application thereof

Abstract

The invention provides a spandex filament with a skin-core structure and a preparation method and application thereof.The spandex filament comprises a skin layer and a core layer, preparation raw materials of the skin layer comprise polyether glycol, diisocyanate A, a chain extender A and a chain terminator A, preparation raw materials of the core layer comprise polyester glycol, diisocyanate B, a chain extender B and a chain terminator B, and the core layer comprises polyester glycol, diisocyanate A, a chain extender B and a chain terminator B; preparation raw materials of the skin layer and the core layer do not comprise polyether ester diol; the preparation raw material of the core layer comprises polyester glycol, the preparation raw material of the skin layer comprises polyether glycol, the preparation raw materials of the skin layer and the core layer do not comprise polyether ester glycol, pure polyether glycol is adopted as the soft segment of the skin layer material, pure polyester glycol is adopted as the soft segment of the core layer material, and the soft segment of the core layer material does not comprise polyether ester glycol. The finally obtained spandex filament with the skin-core structure has excellent heat resistance and alkali resistance on the premise of having excellent mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of spandex filaments, and particularly relates to a spandex filament with a skin-core structure, a preparation method thereof, and an application thereof. Background Art

[0002] Spandex filament, full name spandex fiber, is short for polyurethane fiber. It is a new type of fiber with many excellent textile properties, having good elasticity and elastic recovery rate. It also has the characteristics of fine fineness, high strength, small specific gravity, good dyeability and fastness, etc. The elastic fabric woven with it is comfortable, fitting, and highly elastic, and has the reputation of the second skin of the human body. Therefore, it is widely used in clothing fabrics.

[0003] Conventional spandex filaments generally use polytetramethylene ether glycol (PTMEG) as the soft segment. Due to its good regularity and high phase separation degree from the hard segment, PTMEG can endow polyurethane fibers with excellent elasticity and elongation at break. However, using PTMEG alone as the soft segment will result in poor mechanical properties and low tensile tension of the obtained spandex filaments, making it easy to break during the subsequent application of the spandex filaments when mixed with other fibers. Making the spandex filaments into a skin-core structure can effectively improve their mechanical properties.

[0004] At present, there have been many reports on skin-core structure spandex. CN112127015A discloses a skin-core spandex. By coating a layer of polyester-type polyurethane stock solution on the surface of the formed polyether-type polyurethane fiber and heating and curing it, a spandex filament with a skin-core structure is obtained; however, the skin-core spandex prepared by this method has disadvantages such as uneven coating and coating peeling off after long-term use, and the hydrolysis resistance of polyester-type polyurethane is inferior to that of polyether-type polyurethane, resulting in poor hydrolysis resistance of the obtained skin-core spandex.

[0005] CN107956127A discloses a preparation method of a polyurethane elastic fiber with a skin-core structure. By adjusting the types and contents of the spinning solution additives in the skin and core layers, the additives are enriched in the skin layer to achieve the purpose of enhancing the environmental tolerance of the fiber, changing the surface properties of the fiber, and reducing the use cost of the additives. The key to the preparation of the skin-core structure polyurethane elastic fiber lies in: 1) preparing an N,N-dimethylacetamide solution of polyurethane-polyurea, aging it to obtain the core layer spinning solution, and performing spinning and stretching through a spinneret and drying at a high temperature in the first channel to prepare the core layer polyurethane elastic fiber; 2) taking a part of the above polyurethane-polyurea solution, adding additives for enhancing the environmental tolerance of the fiber or changing the surface properties of the fiber to prepare the skin layer spinning solution, coating the skin layer spinning solution on the surface of the core layer fiber through a special structure coating device, drying at a high temperature in the second channel, and then performing oiling and winding to form the skin-core structure polyurethane elastic fiber; however, the method provided by this invention has disadvantages such as complex operation and high equipment cost.

[0006] CN113774522A discloses a polyurethane elastic fiber with high elongation and high strength and its preparation method. After obtaining a polyurethane prepolymer by reacting a polyether diol, a polyether ester diol, and a diisocyanate, it is dissolved in a polar solvent, and a chain extender and a chain terminator are added to prepare polyurethane urea stock solution A; after obtaining a polyurethane prepolymer by reacting a polyester diol, a polyether ester diol, and a diisocyanate, it is dissolved in a polar solvent, and a chain extender and a chain terminator are added to prepare polyurethane urea stock solution B; using polyurethane urea stock solution A as the skin layer material and polyurethane urea stock solution B as the core layer material, a fiber with a skin-core structure is prepared through a spinneret assembly; the fiber with a skin-core structure volatilizes the polar solvent through a high-temperature tunnel, and an oil agent is applied, then the polyurethane elastic fiber with high elongation and high strength can be obtained. By introducing an aromatic polyester diol, its strength is improved, and by introducing a high-molecular-weight polyether ester diol, its elongation at break is improved; however, the raw materials used in this method have a relatively high cost, and the skin layer is a mixed stock solution of a polyether diol and a polyether ester diol, which, compared with a pure polyether diol, still results in insufficient alkali resistance and heat resistance of the obtained spandex filaments.

[0007] Therefore, developing a spandex filament with excellent heat resistance, alkali resistance, and mechanical properties is an urgent technical problem to be solved in this field. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a spandex filament with a skin-core structure, its preparation method and application. The spandex filament includes a skin layer and a core layer. By defining the raw materials for preparing the skin layer and the core layer, especially by defining that the raw materials for preparing the skin layer and the core layer do not include polyether ester diol, the obtained spandex filament has more excellent heat resistance and alkali resistance on the premise of having excellent mechanical properties.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] In the first aspect, the present invention provides a spandex filament with a skin-core structure, and the spandex filament includes a skin layer and a core layer;

[0011] The raw materials for preparing the skin layer include a polyether diol, diisocyanate A, chain extender A, and chain terminator A;

[0012] The raw materials for preparing the core layer include a polyester diol, diisocyanate B, chain extender B, and chain terminator B;

[0013] And the raw materials for preparing the skin layer and the core layer do not include polyether ester diol.

[0014] The spandex filament with a skin-core structure provided by the present invention includes a skin layer and a core layer. By defining that the raw materials for preparing the skin layer include polyether diol, diisocyanate A, chain extender A, and chain terminator A, and the raw materials for preparing the core layer include polyester diol, diisocyanate B, chain extender B, and chain terminator B, and further defining that neither the raw materials for the skin layer nor the raw materials for the core layer include polyether ester diol, using pure polyether diol as the soft segment of the skin layer material and pure polyester diol as the soft segment of the core layer material, the finally prepared spandex filament with a skin-core structure has more excellent heat resistance and alkali resistance on the basis of excellent mechanical properties.

[0015] Preferably, the raw materials for preparing the skin layer include the following components by weight:

[0016]

[0017] Among them, the polyether diol can be 74 parts by weight, 76 parts by weight, 78 parts by weight, 80 parts by weight, 82 parts by weight, or 84 parts by weight, etc.

[0018] The diisocyanate A can be 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, or 22 parts by weight, etc.

[0019] The chain extender A can be 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, or 5.5 parts by weight, etc.

[0020] The chain terminator A can be 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, or 1.4 parts by weight, etc.

[0021] Preferably, the polyether diol includes any one or a combination of at least two of polytetramethylene ether glycol, polyethylene glycol, or polypropylene glycol.

[0022] Preferably, the diisocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate, and more preferably diphenylmethane diisocyanate.

[0023] Preferably, the chain extender A includes a diamine having 2 to 30 carbon atoms (such as 3, 6, 9, 12, 15, 18, 21, 24, or 28, etc.).

[0024] Preferably, the diamine having 2 to 30 carbon atoms includes any one or a combination of at least two of ethylenediamine, propylenediamine, trimethylenediamine, pentamethylenediamine, methylpentamethylenediamine, methylpropylenediamine, hexamethylenediamine, triethylenediamine, xylylenediamine, phenylenediamine, diaminocyclohexane, or hexamethylenediamine.

[0025] Preferably, the chain terminator A includes a primary amine having 2 to 20 carbon atoms (such as 2, 4, 6, 8, 10, 12, 14, 16, or 18, etc.).

[0026] Preferably, the primary amine having 2 to 20 carbon atoms includes any one or a combination of at least two of diethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, diethylamine, dimethylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, diethylamine, dipropylamine, cyclohexylamine, or ethanolamine.

[0027] Preferably, the raw material for preparing the skin layer further includes a hydrolysis-resistant agent A.

[0028] As a preferred technical solution of the present invention, adding the hydrolysis-resistant agent A to the raw material for preparing the skin layer of the spandex filament can further improve the hydrolysis resistance of the spandex filament.

[0029] Preferably, based on the total mass of the raw material for preparing the skin layer being 100%, the content of the hydrolysis-resistant agent A is 0.2 to 3%, such as 0.4%, 0.6%, 0.8%, 1%, 1.5%, 2%, or 2.5%, etc.

[0030] Preferably, the hydrolysis-resistant agent A includes any one or a combination of at least two of carbodiimide, polycarbodiimide, or cellulose ester, and is further preferably cellulose ester.

[0031] Preferably, the cellulose ester includes any one or a combination of at least two of cellulose formate, cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate.

[0032] Preferably, the raw material for preparing the core layer includes the following components by weight:

[0033]

[0034] Among them, the polyester diol can be 72 parts by weight, 74 parts by weight, 76 parts by weight, 78 parts by weight, 80 parts by weight, 82 parts by weight, or 84 parts by weight, etc.

[0035] The diisocyanate B can be 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, or 24 parts by weight, etc.

[0036] Preferably, the polyester diol B includes polyester diol, polycaprolactone diol or polycarbonate diol.

[0037] Preferably, the diisocyanate B includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate, and is further preferably diphenylmethane diisocyanate.

[0038] Preferably, the chain extender B includes a diamine having 2 to 30 carbon atoms (such as 3, 6, 9, 12, 15, 18, 21, 24 or 28, etc.).

[0039] Preferably, the diamine having 2 to 30 carbon atoms includes any one or a combination of at least two of ethylenediamine, propylenediamine, trimethylenediamine, pentamethylenediamine, methylpentamethylenediamine, methylpropylenediamine, hexamethylenediamine, triethylenediamine, xylylenediamine, phenylenediamine, diaminocyclohexane or hexamethylenediamine.

[0040] Preferably, the chain terminator B includes a primary amine having 2 to 20 carbon atoms (such as 2, 4, 6, 8, 10, 12, 14, 16 or 18, etc.).

[0041] Preferably, the primary amine having 2 to 20 carbon atoms includes any one or a combination of at least two of diethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine diethylamine, dimethylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, diethylamine, dipropylamine, cyclohexylamine or ethanolamine.

[0042] Preferably, the raw materials for preparing the core layer further include other additives.

[0043] Preferably, the other additives include hydrolysis resistance additive B and chlorine resistance agent.

[0044] Preferably, the raw materials for preparing the skin layer and the core layer both further include a solvent.

[0045] Preferably, the solvent includes N,N-dimethylacetamide.

[0046] Preferably, the mass ratio of the skin layer to the core layer is (2 to 9):(8 to 1), such as 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 or 8:2, etc.

[0047] In a second aspect, the present invention provides a method for preparing a spandex fiber having a skin-core structure as described in the first aspect, and the preparation method includes the following steps:

[0048] (1) React the polyether diol with diisocyanate A and then dissolve the product in a solvent to obtain a skin-layer polyurethane prepolymer solution; react the polyester diol with diisocyanate B and then dissolve the product in a solvent to obtain a core-layer polyurethane prepolymer solution;

[0049] (2) React the skin-layer polyurethane prepolymer solution obtained in step (1), the chain extender A for the skin layer, and the chain terminator A for the skin layer, and optionally add a hydrolysis-resistant agent A and cure to obtain a skin-layer spinning dope; react the core-layer polyurethane prepolymer solution obtained in step (1), the chain extender B for the core layer, and the chain terminator B for the core layer, and optionally add other auxiliaries and cure to obtain a core-layer spinning dope;

[0050] (3) Spin the skin-layer spinning dope and the core-layer spinning dope obtained in step (2) through a spinneret skin-core component to obtain the spandex fiber having a skin-core structure.

[0051] The preparation method provided by the present invention first separately prepares a skin-layer spinning dope and a core-layer spinning dope; then respectively feeds the skin-layer spinning dope and the core-layer spinning dope into a spinneret skin-core component having two flow paths of a skin layer and a core layer for spinning, and finally converges and extrudes into filaments to obtain the spandex fiber having a skin-core structure.

[0052] Preferably, the spinning in step (3) is dry spinning.

[0053] In a third aspect, the present invention provides a clothing textile, and the clothing textile includes the spandex fiber having a skin-core structure as described in the first aspect.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The spandex fiber having a skin-core structure provided by the present invention includes a skin layer and a core layer. The preparation raw materials of the skin layer include polyether diol, diisocyanate A, chain extender A, and chain terminator A. The preparation raw materials of the core layer include polyester diol, diisocyanate B, chain extender B, and chain terminator B, and the preparation raw materials of both the skin layer and the core layer do not include polyether ester diol; by defining that the preparation raw materials of the core layer include polyester diol, the preparation raw materials of the skin layer include polyether diol, and defining that the preparation raw materials of both the skin layer and the core layer do not include polyether ester diol, using pure polyether diol as the soft segment of the skin layer material and pure polyester diol as the soft segment of the core layer material, the finally obtained spandex fiber having a skin-core structure can have excellent heat resistance and alkali resistance on the premise of having excellent mechanical properties. Detailed Embodiments

[0056] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0057] Some raw material information involved in the specific embodiment part of the present invention is as follows:

[0058] Polytetramethylene ether glycol: PTMEG, number average molecular weight is 1810;

[0059] Polypropylene glycol: PPG, number average molecular weight is 2000;

[0060] Diphenylmethane diisocyanate: MDI;

[0061] Isophorone diisocyanate: IPDI;

[0062] Polyester diol B1: Condensed from adipic acid and 1,4-butanediol, number average molecular weight is 2000;

[0063] Polycaprolactone diol: number average molecular weight is 2000;

[0064] Polyether ester diol: Condensed from succinic acid, butanediol and polytetrahydrofuran ether glycol, the molecular weight of polytetrahydrofuran ether glycol is 550, and the molecular weight of polyether ester diol is 3200.

[0065] Examples 1-9 and Comparative Examples 1-4

[0066] A spandex filament with a skin-core structure includes a skin layer and a core layer; among them, the mass ratio of the skin layer and the core layer and the components and dosages of each component in the preparation raw materials are shown in Table 1. In Table 1, the dosages of each component are all "parts by weight";

[0067] Table 1

[0068]

[0069]

[0070] The preparation methods of the spandex filaments with a skin-core structure provided in Examples 1-8 and Comparative Examples 1-4 include the following steps:

[0071] (1) React polyether diol and diisocyanate A at 90 °C for 120 min to obtain a polyurethane prepolymer, and dissolve it in N,N-dimethylacetamide to obtain a skin layer polyurethane prepolymer solution;

[0072] React polyester diol and diisocyanate B at 90 °C for 120 min to obtain a polyurethane prepolymer, and dissolve it in N,N-dimethylacetamide to obtain a core layer polyurethane prepolymer solution;

[0073] (2) React the cortical polyurethane prepolymer solution, chain extender A, and chain terminator A obtained in step (1) at 8 °C for 1 min, add hydrolysis-resistant agent A, and cure at 40 °C for 35 h to obtain a cortical spinning dope with a solid content of 35%.

[0074] React the core polyurethane prepolymer solution, chain extender B, and chain terminator B obtained in step (1) at 8 °C for 1 min, and cure at 40 °C for 35 h to obtain a core spinning dope with a solid content of 35%.

[0075] (3) Pass the cortical spinning dope and core spinning dope obtained in step (2) through a spinneret skin-core assembly, and perform dry spinning at 260 °C at a speed of 900 m / min to obtain the 3-hole, 40D spandex yarn with a skin-core structure.

[0076] Comparative Example 5

[0077] A spandex yarn, the preparation raw materials of which include the following components by weight:

[0078]

[0079]

[0080] The preparation method of the spandex yarn provided in this comparative example includes the following steps:

[0081] (1) React PTMEG and MDI at 90 °C for 120 min to obtain a polyurethane prepolymer, and dissolve it in N,N-dimethylacetamide to obtain a polyurethane prepolymer solution.

[0082] (2) React the cortical polyurethane prepolymer solution, ethylenediamine, and diethylamine obtained in step (1) at 8 °C for 1 min, add cellulose ester, and cure at 40 °C for 35 h to obtain a spinning dope with a solid content of 35%.

[0083] (3) Pass the spinning dope obtained in step (2) through a spinneret assembly, and perform dry spinning at 260 °C at a speed of 900 m / min to obtain the 3-hole, 40D spandex yarn with a skin-core structure.

[0084] Comparative Example 6

[0085] A spandex yarn, the preparation raw materials of which include the following components by weight:

[0086]

[0087] The preparation method of the spandex yarn provided in this comparative example includes the following steps:

[0088] (1) React the polyester diol B1 and MDI at 90 °C for 120 min to obtain a polyurethane prepolymer, and dissolve it in N,N-dimethylacetamide to obtain a polyurethane prepolymer solution;

[0089] (2) React the core layer polyurethane prepolymer solution obtained in step (1), ethylenediamine and diethylamine at 8 °C for 1 min, and cure at 40 °C for 35 h to obtain a spinning dope with a solid content of 35%;

[0090] (3) Pass the spinning dope obtained in step (2) through a spinneret skin-core assembly, and carry out dry spinning at 260 °C at a speed of 900 m / min to obtain the 3-hole, 40D spandex yarn with a skin-core structure.

[0091] Performance test:

[0092] (1) Tensile strength at 300% elongation (SS300), breaking strength (DS) and elongation at break (DE): Test according to the method provided in the industry standard FZ / T 50006-2013 "Test Method for Tensile Properties of Spandex Yarn";

[0093] (2) Alkaline resistance A: Dissolve 30 g of NaOH in 1000 mL of water, add 2 g of fatty alcohol polyoxyethylene ether to it, then put the spandex yarn into the above solution, keep it at 100 °C for 60 min, and test the retention rate of breaking strength (DS) of the spandex before and after being treated with the alkaline solution;

[0094] (3) Alkaline resistance B: Wind the spandex yarn with an iron frame and place it in a 10% molar concentration NaOH alkaline solution tank. After the alkaline solution tank is heated to 80 °C, keep it at a constant temperature for 90 min. Test the breaking strength values of the spandex yarn after and before the alkaline treatment respectively, and calculate the retention rate of breaking strength (DS);

[0095] (4) Heat resistance: Stretch the sample 2.0 times and fix it on a shaping bracket, pre-shape it in an oven at 190 °C for 1 min, cool it and put it into water, place it in a sealed container, treat it at 130 °C for 40 min, dry it and then put it into the oven for shaping at 190 °C for 1 min, take it out and air-dry it to cool naturally, test the breaking strength, and calculate the retention rate of breaking strength before and after the treatment.

[0096] Test the spandex yarns provided in Examples 1-8 and Comparative Examples 1-6 according to the above test methods, and the test results are shown in Table 2:

[0097] Table 2

[0098]

[0099]

[0100] It can be seen from the data in Table 2 that for the spandex filaments with a skin-core structure provided by the present invention, when using pure polyether diol as the soft segment of the skin layer material and pure polyester diol as the soft segment of the core layer material, the finally obtained spandex filaments with a skin-core structure can have excellent heat resistance and alkali resistance on the premise of having excellent mechanical properties;

[0101] Specifically, for the spandex filaments provided in Examples 1 to 3, the strength at 300% elongation is 12.7 - 13.8 g, the breaking strength is 49.1 - 55.8 g, and the breaking elongation rate is 501 - 539%; the alkali resistance test shows that the retention rate of the breaking strength after soaking in an alkaline solution containing fatty alcohol polyoxyethylene ether is 60.8 - 63.9%, and the retention rate of the breaking elongation rate after soaking in a pure alkaline solution is even as high as 83.2 - 86.7%; the heat resistance shows that the retention rate of the breaking strength after heat treatment is 57.7 - 69.1%;

[0102] Compared with Example 1, the alkali resistance and heat resistance of the spandex filaments provided in Comparative Examples 1 to 4 have significantly decreased, which is caused by the addition of polyether ester in their skin layer or core layer; the heat resistance and alkali resistance of the spandex filaments provided in Comparative Examples 5 to 6 also have decreased, which is caused by the fact that they do not have a skin-core structure;

[0103] Compared with Example 1, the alkali resistance of the spandex filaments provided in Examples 4 to 5 has also decreased, which is caused by the fact that Example 4 does not use cellulose ester as a hydrolysis-resistant agent, and Example 5 directly does not add a hydrolysis-resistant agent;

[0104] Compared with Example 1, the alkali resistance and heat resistance of the spandex filaments provided in Examples 6 to 8 are also different, which shows that the skin-core ratio of the spandex filaments will also affect their heat resistance and alkali resistance.

[0105] The applicant declares that the present invention uses the above examples to illustrate a spandex filament with a skin-core structure and its preparation method and application, but the present invention is not limited to the above examples, that is, it does not mean that the present invention must rely on the above examples to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A spandex filament with a skin-core structure, characterized in that, The spandex filament includes a skin layer and a core layer; The raw materials for preparing the skin layer include polyether diol, diisocyanate A, chain extender A, and chain terminator A; The raw materials for preparing the core layer include polyester diol, diisocyanate B, chain extender B, and chain terminator B; And the raw materials for preparing the skin layer and the core layer do not include polyether ester diol.

2. The spandex fiber according to claim 1, wherein The raw materials for preparing the skin layer include the following components by weight: Preferably, the polyether diol includes any one or a combination of at least two of polytetramethylene ether glycol, polyethylene glycol, or polypropylene glycol; Preferably, the diisocyanate A includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate, and is further preferably diphenylmethane diisocyanate; Preferably, the chain extender A includes a diamine having 2 to 30 carbon atoms; Preferably, the diamine having 2 to 30 carbon atoms includes any one or a combination of at least two of ethylenediamine, propylenediamine, trimethylenediamine, pentamethylenediamine, methylpentamethylenediamine, methylpropylenediamine, hexamethylenediamine, xylylenediamine, phenylenediamine, diaminocyclohexane, or hexamethylenediamine; Preferably, the chain terminator A includes a primary amine having 2 to 20 carbon atoms; Preferably, the primary amine having 2 to 20 carbon atoms includes any one or a combination of at least two of diethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine diethylamine, dimethylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, diethylamine, dipropylamine, cyclohexylamine, or ethanolamine.

3. The spandex filament according to claim 1 or 2, characterized in that, The raw materials for preparing the skin layer further include hydrolysis-resistant agent A; Preferably, based on the total mass of the raw materials for preparing the skin layer being 100%, the content of the hydrolysis-resistant agent A is 0.2 to 3%; Preferably, the hydrolysis-resistant agent A includes any one or a combination of at least two of carbodiimide, polycarbodiimide, or cellulose ester, and is further preferably cellulose ester; Preferably, the cellulose ester includes any one or a combination of at least two of cellulose formate, cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate.

4. The spandex filament according to any one of claims 1 to 3, characterized in that, The raw materials for preparing the core layer include the following components by weight: Preferably, the polyester diol includes polyester diol, polycaprolactone diol, or polycarbonate diol; preferably, the diisocyanate B includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate, and is further preferably diphenylmethane diisocyanate; Preferably, the chain extender B includes a diamine having 2 to 30 carbon atoms; Preferably, the diamine having 2 to 30 carbon atoms includes any one or a combination of at least two of ethylenediamine, propylenediamine, trimethylenediamine, pentamethylenediamine, methylpentamethylenediamine, methylpropylenediamine, hexamethylenediamine, triethylenediamine, xylylenediamine, phenylenediamine, diaminocyclohexane, or hexamethylenediamine; Preferably, the chain terminator B includes a primary amine having 2 to 20 carbon atoms; Preferably, the monoamine having 2 to 20 carbon atoms includes any one or a combination of at least two of diethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, diethylamine, dimethylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, diethylamine, dipropylamine, cyclohexylamine, or ethanolamine.

5. The spandex fiber according to any one of claims 1 to 4, characterized in that, The raw materials for preparing the core layer further include other additives; Preferably, the other additives include a hydrolysis-resistant additive B and a chlorine-resistant agent.

6. The spandex filament according to any one of claims 1 to 5, characterized in that The raw materials for preparing the skin layer and the core layer both further include a solvent; Preferably, the solvent includes N,N-dimethylacetamide.

7. The spandex filament according to any one of claims 1 to 6, characterized in that, The mass ratio of the skin layer to the core layer is (2 to 9):(8 to 1).

8. A method for preparing a spandex filament having a skin-core structure as described in any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: (1) React polyether diol and diisocyanate A and then dissolve the reaction product in a solvent to obtain a skin-layer polyurethane prepolymer solution; react polyester diol and diisocyanate B and then dissolve the reaction product in a solvent to obtain a core-layer polyurethane prepolymer solution; (2) React the skin-layer polyurethane prepolymer solution obtained in step (1), an extender A for the skin layer, and a chain terminator A for the skin layer, add an optionally added hydrolysis-resistant agent A, and cure to obtain a skin-layer spinning dope; react the core-layer polyurethane prepolymer solution obtained in step (1), an extender B for the core layer, and a chain terminator B for the core layer, add an optionally added other additive, and cure to obtain a core-layer spinning dope; (3) Spin the skin-layer spinning dope and the core-layer spinning dope obtained in step (2) through a spinneret skin-core assembly to obtain the spandex filament having a skin-core structure.

9. The preparation method according to claim 8, characterized in that, The spinning in step (3) is dry spinning.

10. A clothing textile, characterized in that, The clothing textile includes the spandex filament having a skin-core structure according to any one of claims 1 to 7.

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