Easily-dyed composite spandex fiber as well as preparation method and application thereof

Abstract

The invention provides an easy-to-dye composite spandex fiber and a preparation method and application thereof.The easy-to-dye composite spandex fiber is of a skin-core structure and comprises a skin layer and a core layer, the material of the skin layer comprises first polyurethane-urea and thermoplastic polyurethane, and the material of the core layer comprises second polyurethane-urea; the skin layer made of the specific materials and the core layer made of the specific materials are matched, so that the obtained composite spandex fiber with the skin-core structure has an excellent dyeing effect on the basis of having excellent heat resistance, spinnability and mechanical properties; the spandex fiber has high dye-uptake and high fixation rate on acid dyes and reactive dyes, and meets the use requirements of most application fields on the spandex fiber.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of spandex, and particularly relates to an easy-to-dye composite spandex fiber as well as a preparation method and application thereof. BACKGROUND

[0002] Spandex fiber is a short name of polyurethane fiber, has the characteristics of fine fineness, high strength, small specific gravity, high elasticity and high elastic recovery rate, has the reputation of human second skin, and is currently widely applied to garment fabrics. However, due to the lack of active groups in the structure of spandex fiber, dye molecules are difficult to enter the inside of the fiber, resulting in dyeing difficulty.

[0003] At present, there are mainly two methods to improve the dyeing effect of spandex fiber: (1) adding a dyeing aid, but the common dyeing aid has general colorability and color fastness, cannot well solve the problem of poor colorability of spandex, and the common dyeing aid generally has poor compatibility with spandex, and subsequent migration problems are prone to occur, in addition, part of the dyeing aid will obviously affect the performance of spandex fiber, and in the subsequent processing and use process, the performance degradation of spandex will be accelerated; (2) modifying the molecular structure of spandex, introducing an easy-to-dye structure on the molecular chain of spandex, but this method will destroy the molecular structure of spandex itself, resulting in the decline of physical and mechanical properties, which cannot meet the requirements of most application fields for spandex fiber, and is difficult to popularize and use.

[0004] Therefore, in view of the above technical problems, it is urgent to develop an easy-to-dye composite spandex fiber with good dyeing effect and excellent comprehensive performance. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide an easy-to-dye composite spandex fiber and a preparation method and application thereof. The easy-to-dye composite spandex fiber has a skin-core structure, and by reasonably selecting the materials of the skin layer and the core layer, it has excellent heat resistance, spinnability and mechanical properties, and also has good dyeing performance, which can significantly improve the dyeing rate and color fixing rate of active dyes and acid dyes.

[0006] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides an easy-to-dye composite spandex fiber, which has a skin-core structure and comprises a skin layer and a core layer.

[0008] The material of the skin layer comprises a first polyurethane-urea and a thermoplastic polyurethane.

[0009] The material of the core layer comprises a second polyurethane-urea.

[0010] The easy-to-dye composite spandex fiber provided by the present application has a skin-core structure, including a skin layer and a core layer, the material of the skin layer includes first polyurethane-urea and thermoplastic polyurethane, and the material of the core layer includes second polyurethane-urea; first, by selecting the first polyurethane-urea and the thermoplastic polyurethane to match as the material of the skin layer, the hydrophilicity of the skin layer can be effectively improved, and then the dye uptake and color fixation rate of the dye on the spandex fiber can be effectively improved, so that the obtained composite spandex fiber has excellent dyeing effect; second, by selecting the second polyurethane-urea as the material of the core layer, the excellent heat resistance, hydrolysis resistance and mechanical properties of the spandex fiber can be effectively retained, and then the deterioration of the spandex fiber in high temperature environment can be reduced, so that the obtained composite spandex fiber can have excellent comprehensive performance.

[0011] Preferably, the mass percentage content of the skin layer in the easy-to-dye composite spandex fiber is 20-80%, for example, 20%, 30%, 40%, 50%, 60%, 70% or 80%, etc.

[0012] Preferably, the mass percentage content of the first polyurethane-urea in the material of the skin layer is 10-90%, for example, 10%, 20%, 40%, 60%, 80% or 90%, etc.; if the mass percentage content of the first polyurethane-urea in the material of the skin layer is too low, the mass percentage content of the thermoplastic polyurethane in the material of the skin layer will be too high, and then the mechanical properties and heat resistance of the obtained composite spandex fiber will be poor, and the performance will deteriorate obviously after post-processing; if the mass percentage content of the first polyurethane-urea in the material of the skin layer is too high, the mass percentage content of the thermoplastic polyurethane in the material of the skin layer will be too low, which will easily lead to poor dye uptake and color fastness of the obtained composite spandex fiber.

[0013] Preferably, the raw materials for preparing the first polyurethane-urea include first polyol A, first isocyanate A, diamine chain extender A and amine chain terminator A.

[0014] Preferably, the raw materials for preparing the second polyurethane-urea include first polyol B, first isocyanate B, diamine chain extender B and amine chain terminator B.

[0015] Preferably, the number average molecular weight of the first polyol A and the first polyol B is independently 1000-3000 g / mol, for example, 1000 g / mol, 1200 g / mol, 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2400 g / mol, 2600 g / mol, 2800 g / mol or 3000 g / mol, etc.

[0016] Preferably, the first polyol A and the first polyol B each independently comprise any one or a combination of at least two of polytetramethylene ether glycol, polyethylene glycol, or polypropylene glycol, further preferably polytetramethylene ether glycol.

[0017] Preferably, the first isocyanate A and the first isocyanate B each independently comprise any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate, further preferably diphenylmethane diisocyanate.

[0018] Preferably, the diamine chain extender A and the diamine chain extender B each independently are a diamine having a carbon atom number of 2 to 30 (e.g., 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or 28, etc.).

[0019] Preferably, the diamine having a carbon atom number of 2 to 30 comprises any one or a combination of at least two of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, methylpentylenediamine, methylpropylenediamine, hexylenediamine, xylylenediamine, phenylenediamine, diaminocyclohexane, or hexamethylenediamine.

[0020] Preferably, the amine chain terminator A and the amine chain terminator B each independently comprise a primary amine having a carbon atom number of 2 to 20 (e.g., 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or 28, etc.) and / or a tertiary amine-containing primary amine having a carbon atom number of 2 to 20 (e.g., 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or 28, etc.).

[0021] Preferably, the primary amine having a carbon atom number of 2 to 20 comprises any one or a combination of at least two of diethylamine, isopropylamine, n-butylamine, t-butylamine, hexylamine diethylamine, dimethylamine, di-n-butylamine, di-t-butylamine, diisobutylamine, diisopropylamine, diethylamine, dipropylamine, or cyclohexylamine, or ethanolamine.

[0022] Preferably, the tertiary amine-containing primary amine having a carbon atom number of 2 to 20 comprises any one or a combination of at least two of N,N-dimethylethylene-diamine, N,N-diethylethylene-diamine, N,N-dimethyl-1,3-propanediamine, or N,N-diethyl-1,3-propanediamine.

[0023] Preferably, the amine chain terminator A comprises a combination of a primary amine without tertiary amine group having a carbon atom number of 2-20 and a primary amine with tertiary amine group having a carbon atom number of 2-20, and the limitation that the amine chain terminator A comprises a combination of the above two primary amines can further improve the dye uptake of the obtained composite spandex fiber while ensuring that it has relatively high mechanical properties.

[0024] Preferably, the molar ratio of the primary amine without tertiary amine group having a carbon atom number of 2-20 and the primary amine with tertiary amine group having a carbon atom number of 2-20 is (5-9):(5-1), such as 5:5, 6:4, 7:3, 8:2, or 9:1, etc.

[0025] Preferably, the amine chain terminator B comprises a primary amine without tertiary amine group having a carbon atom number of 2-20.

[0026] Preferably, the preparation method of the first polyurethane-urea comprises: reacting the first polyol A and the first isocyanate A at 70-95℃ (such as 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, 92℃, or 95℃, etc.) for 0.5-5h (such as 0.5h, 1h, 2h, 3h, 4h, or 5h, etc.), to obtain a polyurethane prepolymer with a mass percentage of NCO groups of 2-3.5% (such as 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, or 3.5%, etc.); dissolving the obtained polyurethane prepolymer in a solvent to obtain a polyurethane prepolymer solution; and then adding the diamine chain extender A and the amine chain terminator A to the obtained polyurethane prepolymer solution to perform a chain extension reaction, to obtain the first polyurethane-urea.

[0027] Preferably, the molar ratio of the diamine chain extender A and the amine chain terminator A is (8-20):1, such as 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, or 20:1, etc.; and the molar ratio of the total amount of amino groups in the diamine chain extender A and the amine chain terminator A to the isocyanate groups (-NCO) in the polyurethane prepolymer in the chain extension reaction is (1-1.4):1, such as 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1, or 1.4:1, etc., preferably (1.02-1.2):1; and the solvent comprises N,N-dimethylacetamide.

[0028] In the present application, the preparation method of the second polyurethane-urea refers to the preparation method of the first polyurethane-urea.

[0029] In the present application, since the preparation of the first polyurethane-urea and the second polyurethane-urea is carried out in a solvent, the finally obtained first polyurethane-urea and the second polyurethane-urea are both dissolved in the solvent, and then can be directly used as a spinning dope without additional addition of a solvent.

[0030] Preferably, the mass percentage of the thermoplastic polyurethane in the material of the skin layer is 10-90%, for example, 10%, 20%, 40%, 60%, 80% or 90%, etc.

[0031] Preferably, the Shore hardness of the thermoplastic polyurethane is 60-95A, for example, 60A, 65A, 70A, 75A, 80A, 85A, 90A or 95A, etc., and further preferably 75-85A; if the Shore hardness of the thermoplastic polyurethane is too low, it will result in poor mechanical properties of the spandex fiber and affect the spinnability; if the Shore hardness of the thermoplastic polyurethane is too high, it will also affect the spinnability of the spandex fiber.

[0032] In the present application, the Shore hardness of the thermoplastic polyurethane is tested according to the method provided in GB / T 531.1.

[0033] Preferably, the raw material for preparing the thermoplastic polyurethane includes a second polyol, a second isocyanate and a diol chain extender.

[0034] Preferably, the number average molecular weight of the second polyol is 800-3000 g / mol, for example, 800 g / mol, 1000 g / mol, 1200 g / mol, 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2400 g / mol, 2600 g / mol or 2800 g / mol, etc.

[0035] Preferably, the second polyol includes polyethylene glycol and / or polypropylene glycol, and further preferably polyethylene glycol; further preferably, the polyethylene glycol is selected as the second polyol, which helps to improve the hydrophilicity of the second polyurethane-urea, and further helps to improve the dye uptake and color fastness of the obtained composite spandex fiber.

[0036] Preferably, the second isocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate, and further preferably diphenylmethane diisocyanate.

[0037] Preferably, the diol chain extender is a dihydric alcohol with a carbon atom number of 2-10 (for example, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.).

[0038] Preferably, the dihydric alcohol having a carbon number of 2-10 includes any one or a combination of at least two of ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, methyl pentylene glycol, neopentyl glycol, methyl propylene glycol, hexylene glycol, heptylene glycol, octylene glycol, or nonylene glycol.

[0039] Preferably, the method for preparing the thermoplastic polyurethane includes reacting the second polyol, the second isocyanate, and the dihydric alcohol chain extender at 140-200°C (e.g., 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C, etc.) to obtain the thermoplastic polyurethane.

[0040] Preferably, the material of the sheath layer further includes a dyeing assistant, and the addition of the dyeing assistant helps to further improve the dyeing performance of the dyeable composite spandex fiber.

[0041] Preferably, the mass percentage of the dyeing assistant in the material of the sheath layer is 0.3-3% (e.g., 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%, etc.).

[0042] Preferably, the dyeing assistant includes any one or a combination of at least two of an amine dyeing assistant, a (meth)acrylic dyeing assistant, a polyamide dyeing assistant, a polyurethane dyeing assistant, a sulfonate dyeing assistant, a carbonate dyeing assistant, or a borate dyeing assistant.

[0043] Preferably, the dyeing assistant includes any one or a combination of at least two of poly(methyl acrylate diethylamine ethyl ester), sodium dibutyl naphthalene sulfonate, sodium carbonate, or sodium borate.

[0044] Illustratively, the dyeing assistant can be selected from any one or a combination of at least two of commercially available 2462B, HAS, TSA-011, or PL-80.

[0045] In a second aspect, the present application provides a method for preparing the dyeable composite spandex fiber as described in the first aspect, and the method includes the following steps:

[0046] (1) mixing the first polyurethane-urea, the thermoplastic polyurethane, and optionally the dyeing assistant to obtain a sheath spinning dope; and using the second polyurethane-urea as a core spinning dope;

[0047] (2) spinning the sheath spinning dope and the core spinning dope obtained in step (1) through a spinneret sheath-core assembly to obtain the dyeable composite spandex fiber.

[0048] The application provides a preparation method of the dyeable composite spandex fiber.

[0049] Preferably, the spinning in step (2) is dry spinning.

[0050] Preferably, after the spinning in step (2) ends, the method further comprises the steps of spraying, stretching and drying and setting.

[0051] In a third aspect, the application provides a garment textile, which comprises the dyeable composite spandex fiber as described in the first aspect.

[0052] Compared with the prior art, the application has the following beneficial effects:

[0053] The dyeable composite spandex fiber provided by the application has a skin-core structure, comprises a skin layer and a core layer, the material of the skin layer comprises first polyurethane-urea and thermoplastic polyurethane, and the material of the core layer comprises second polyurethane-urea; by selecting the skin layer composed of the specific material and the core layer composed of the specific material, the obtained composite spandex fiber with the skin-core structure has excellent heat resistance, spinnability and mechanical properties, and also has excellent dyeing effect, has high dyeing rate and high color fixation rate (color fastness) for reactive dyes and acid dyes, and can meet the use requirements of spandex fibers in most application fields. DETAILED DESCRIPTION

[0054] The technical solutions of the application are further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to understand the application and should not be regarded as specific limitations on the application.

[0055] Unless otherwise specified, the raw materials and devices involved in the embodiments of the application are all conventional materials and devices in the field.

[0056] Embodiment 1

[0057] A dyeable composite spandex fiber has a skin-core structure, which comprises a skin layer with a mass percentage of 50% and a core layer with a mass percentage of 50%;

[0058] The material of the skin layer comprises first polyurethane-urea with a mass percentage of 49%, thermoplastic polyurethane (Shore hardness of 80A) with a mass percentage of 49% and poly (dimethylamino ethyl methacrylate) with a mass percentage of 2%;

[0059] The material of the core layer is second polyurethane-urea with a mass percentage of 100%;

[0060] The preparation method of the first polyurethane-urea and the second polyurethane-urea comprises the following steps: first, polytetramethylene ether glycol (PTMEG, number average molecular weight 1800 g / mol) and diphenyl methane diisocyanate (MDI) are reacted at 75°C for 4.5 h to obtain a polyurethane prepolymer with a mass content of -NCO of 2.65%; then the obtained polyurethane prepolymer is dissolved in N,N-dimethylacetamide to obtain a polyurethane prepolymer solution with a mass content of 35%; finally, ethylenediamine and diethylamine with a molar ratio of 15:1 are added to the obtained polyurethane prepolymer solution at 80°C for chain extension reaction, the total mass content of ethylenediamine and diethylamine in the solution is 8%, and the molar ratio of amino groups to isocyanate groups in the chain extension reaction is controlled to be 1.02:1, to obtain the first polyurethane-urea solution and the second polyurethane-urea solution;

[0061] The preparation method of the thermoplastic polyurethane comprises the following steps: first, polyethylene glycol (PEG, number average molecular weight 2000 g / mol), ethylene glycol and diphenyl methane diisocyanate (MDI) are mixed and reacted in a double-screw extruder through a mixing system to obtain a polymer melt, wherein the molar ratio of hydroxyl groups in PEG and ethylene glycol to -NCO in MDI is 1:0.99, and the temperature of the screw is 145-180°C; then the obtained polymer melt is cut under water and dried to obtain thermoplastic polyurethane particles; finally, the obtained thermoplastic polyurethane particles are dissolved in N,N-dimethylacetamide to obtain a thermoplastic polyurethane solution with a mass content of 35%;

[0062] The preparation method of the easily-dyed composite spandex fiber provided in this embodiment 1 comprises the following steps:

[0063] (1) The first polyurethane-urea solution, the thermoplastic polyurethane solution and poly(methyl acrylate diethylaminoethyl ester) are mixed, and after maturation, a skin layer spinning dope is obtained; the second polyurethane-urea solution is matured and directly used as a core layer spinning dope;

[0064] (2) The skin layer spinning dope and the core layer spinning dope obtained in step (1) are spun through a jet plate skin-core assembly at a speed of 900 m / min at 260°C by dry spinning, and after blowing, stretching and drying, an easily-dyed composite spandex fiber with a fineness of 40D is obtained.

[0065] Embodiment 2

[0066] An easily-dyed composite spandex fiber, which is different from that of embodiment 1 in that the mass percentage content of the first polyurethane-urea in the material of the skin layer is 10%, the mass percentage content of the thermoplastic polyurethane is 88%, and sodium dibutyl naphthalene sulfonate is used to replace poly(methyl acrylate diethylaminoethyl ester) as a dyeing assistant, and the other substances, dosages and preparation methods are referred to embodiment 1.

[0067] Example 3

[0068] A dyeable composite spandex fiber, which is different from Example 1 in that the mass percentage content of the first polyurethane-urea in the material of the skin layer is 88%, the mass percentage content of the thermoplastic polyurethane is 10%, and

[0069] The preparation method of the first polyurethane-urea comprises: first, reacting polytetramethylene ether glycol (PTMEG, number average molecular weight 1800 g / mol) and diphenyl methane diisocyanate (MDI) at 75°C for 4.5h to obtain a polyurethane prepolymer with a mass content of -NCO of 2.65%; then dissolving the obtained polyurethane prepolymer in N,N-dimethylacetamide to obtain a polyurethane prepolymer solution with a mass content of 35%; finally, adding ethylenediamine, diethylamine and N,N-dimethyl ethylenediamine in a molar ratio of 15:0.7:0.3 to the obtained polyurethane prepolymer solution at 80°C for chain extension reaction, the total mass content of ethylenediamine, diethylamine and N,N-dimethyl ethylenediamine in the solution is 8%, and the molar ratio of amino groups to isocyanate groups in the chain extension reaction is controlled to be 1.02:1, to obtain the first polyurethane-urea solution;

[0070] The other substances, amounts and preparation methods are referred to Example 1.

[0071] Example 4

[0072] A dyeable composite spandex fiber, which is different from Example 1 in that the mass percentage content of the first polyurethane-urea in the material of the skin layer is 8%, the mass percentage content of the thermoplastic polyurethane is 90%, and the other substances, amounts and preparation methods are referred to Example 1.

[0073] Example 5

[0074] A dyeable composite spandex fiber, which is different from Example 1 in that the mass percentage content of the first polyurethane-urea in the material of the skin layer is 90%, the mass percentage content of the thermoplastic polyurethane is 8%, and the other substances, amounts and preparation methods are referred to Example 1.

[0075] Example 6

[0076] A dyeable composite spandex fiber, which is different from Example 1 in that polypropylene glycol (number average molecular weight 2000) is used to replace polyethylene glycol, and the other substances, amounts and preparation methods are referred to Example 1.

[0077] Example 7

[0078] A dyeable composite spandex fiber, which is different from example 1 in that polytetramethylene ether glycol (number average molecular weight of 2000) is used to replace polyethylene glycol, and other substances, amounts and preparation methods are referred to example 1.

[0079] Example 8

[0080] A dyeable composite spandex fiber, which is different from example 1 in that polytetramethylene ether glycol (number average molecular weight of 2000) is used to replace polyethylene glycol, and other substances, amounts and preparation methods are referred to example 1.

[0081] Example 9

[0082] A dyeable composite spandex fiber, which is different from example 1 in that the Shore hardness of the thermoplastic polyurethane is 55A, and other substances, amounts and preparation methods are referred to example 1.

[0083] Example 10

[0084] A dyeable composite spandex fiber, which is different from example 1 in that the Shore hardness of the thermoplastic polyurethane is 60D, and other substances, amounts and preparation methods are referred to example 1.

[0085] Example 11

[0086] A dyeable composite spandex fiber, which is different from example 1 in that the mass percentage of the skin layer and the core layer is 22% and 78% respectively, and other substances, amounts and preparation methods are referred to example 1.

[0087] Comparative example 1

[0088] A composite spandex fiber, which is different from example 1 in that the first polyurethane-urea is not added in the material of the skin layer, and only contains 98% of thermoplastic polyurethane and 2% of poly (diethylaminoethyl methacrylate) by mass percentage, and other substances, amounts and preparation methods are referred to example 1.

[0089] Comparative example 2

[0090] A composite spandex fiber, which is different from example 1 in that the thermoplastic polyurethane is not added in the material of the skin layer, and only contains 98% of the first polyurethane-urea and 2% of poly (diethylaminoethyl methacrylate) by mass percentage, and other substances, amounts and preparation methods are referred to example 1.

[0091] Comparative example 3

[0092] An elastane fiber, the material of which comprises 49% of polyurethane-urea, 49% of thermoplastic polyurethane (Shore hardness 80A) and 2% of poly (dimethylaminoethyl methacrylate) (purchased from Penglai Hongwei Chemical Co., Ltd.) by mass percentage;

[0093] The preparation method of the polyurethane-urea comprises the following steps: firstly, polytetramethylene ether glycol (PTMEG, number average molecular weight 1800 g / mol) and diphenyl methane diisocyanate (MDI) are reacted at 75℃ for 4.5h to obtain a polyurethane prepolymer with a mass content of 2.65% of -NCO; then the obtained polyurethane prepolymer is dissolved in N,N-dimethylacetamide to obtain a polyurethane prepolymer solution with a mass content of 35%; finally, ethylenediamine and diethylamine with a molar ratio of 15:1 are added to the obtained polyurethane prepolymer solution at 80℃ for chain extension reaction, the mass content of ethylenediamine and diethylamine in the solution is 8%, and the molar ratio of amino group to isocyanate group in the chain extension reaction is controlled to be 1.02:1, to obtain the polyurethane-urea solution;

[0094] The preparation method of the thermoplastic polyurethane comprises the following steps: polyethylene glycol (PEG, number average molecular weight 2000 g / mol), ethylene glycol and diphenyl methane diisocyanate (MDI) are mixed and reacted by a mixing system in a twin-screw extruder to obtain a polymer melt, wherein the molar ratio of hydroxyl groups in PEG and ethylene glycol to NCO groups in MDI is 1:0.99, and the temperature of the screw is controlled to be 145-180℃; then the obtained polymer melt is cut and dried underwater to obtain thermoplastic polyurethane particles; finally, the obtained thermoplastic polyurethane particles are dissolved in N,N-dimethylacetamide to obtain a thermoplastic polyurethane solution with a mass content of 35%;

[0095] The preparation method of the elastane fiber provided by the comparative example 3 comprises the following steps:

[0096] (1) mixing the polyurethane-urea solution, the thermoplastic polyurethane solution and poly (dimethylaminoethyl methacrylate) to obtain a spinning dope after maturation;

[0097] (2) dry spinning the spinning dope obtained in step (1) through a spinneret at a speed of 900 m / min at 260℃, and forming the elastane fiber through blowing, stretching and drying.

[0098] Comparative example 4

[0099] An elastane fiber, the material of which comprises 98% of polyurethane-urea and 2% of poly (dimethylaminoethyl methacrylate) (purchased from Penglai Hongwei Chemical Co., Ltd.);

[0100] The preparation method of the polyurethane-urea comprises the following steps: firstly, reacting polytetramethylene ether glycol (PTMEG, number average molecular weight 1800 g / mol) and diphenyl methane diisocyanate (MDI) at 75°C for 4.5 h to obtain a polyurethane prepolymer with a mass content of -NCO of 2.65%; then dissolving the obtained polyurethane prepolymer in N,N-dimethylacetamide to obtain a polyurethane prepolymer solution with a mass content of 35%; and finally adding ethylenediamine and diethylamine in a molar ratio of 15:1 to the obtained polyurethane prepolymer solution at 80°C for chain extension reaction, so that the mass content of ethylenediamine and diethylamine in the solution is 8%, and the molar ratio of amino groups to isocyanate groups in the chain extension reaction is controlled to be 1.02:1, to obtain the polyurethane-urea solution.

[0101] The preparation method of the spandex fiber provided by the present comparative example 4 comprises the following steps:

[0102] (1) mixing the polyurethane-urea solution and poly(methyl propylacrylate diethylamine ethyl ester) to obtain a spinning dope after maturation;

[0103] (2) performing dry spinning on the spinning dope obtained in step (1) through a spinneret at a speed of 900 m / min at 260°C, and forming the spandex fiber through blowing, stretching and drying.

[0104] Performance test:

[0105] (1) strength at 300% elongation (SS300), breaking strength (DS) and breaking elongation (DE): tested according to the method provided in the industry standard FZ / T 50006-2013 “Spandex filament tensile property test method”.

[0106] (2) heat resistance: after the spandex fiber is drawn to 2.0 times and fixed on a setting support, pre-setting in an oven at 190°C for 1 min, cooling, placing in water, and treating in a closed container at 130°C for 40 min, drying, and then setting in the oven at 190°C for 1 min, taking out and naturally air-drying and cooling, the breaking strength (DS) is tested, and the heat resistance is the breaking strength retention rate (%) of the spandex fiber before and after treatment;

[0107] (3) dye uptake and color fastness:

[0108] Firstly, the spandex fiber is dyed, and then the maximum absorbance of the dye solution before and after dyeing is measured by using a UV-visible spectrophotometer, and then the dye uptake is calculated according to the following formula: dye uptake = (A0-A1) / A0 x 100%, wherein A0 and A1 are the absorbance of the dye solution before and after dyeing, respectively;

[0109] The color fastness of the spandex fibers after acid dyeing and reactive dyeing is tested according to the scheme provided in GB / T 3921-2008 "Textile color fastness test soaping fastness", and the color transfer is determined by using the standard color transfer sample card, which is divided into 9 grades, i.e. 1, 1-2, 2, 2-3, 3, 3-4, 4, 4-5 and 5, and the closer to 5, the better the color transfer;

[0110] ① Acid dyeing method: first, prepare an acid dyeing solution with a dye concentration of 2 g / L and a pH value of 4.5, wherein the dye is weak acid red, and the bath ratio is 1:40; then, immerse the spandex fiber into the dyeing cup containing the acid dyeing solution, and then put the dyeing cup containing the acid dyeing solution and the spandex fiber into the dyeing machine, and raise the temperature from 40℃ to 100℃ at a rate of 1℃ / min, and keep the temperature for 30 min; after the dyeing is completed, take out the sample, and rinse it in clean water until the water does not change color, and then dry it at room temperature;

[0111] ② Reactive dyeing method: first, prepare a reactive dyeing solution with a dye concentration of 10 g / L, and add anhydrous sodium sulfate to make the concentration 20 g / L, wherein the dye is reactive red, and the bath ratio is 1:40; then, immerse the spandex fiber into the dyeing cup containing the reactive dyeing solution, and then put the dyeing cup containing the reactive dyeing solution and the spandex fiber into the dyeing machine, and raise the temperature from room temperature to 85℃ at a rate of 1℃ / min, and continue to add anhydrous sodium sulfate (concentration of 20 g / L compared to the above reactive dyeing solution) and anhydrous sodium carbonate (concentration of 10 g / L compared to the above reactive dyeing solution) into the dyeing vat, and keep the temperature for 30 min; after the dyeing is completed, take out the sample, and rinse it in clean water until the water does not change color, and then dry it at room temperature.

[0112] (4) Spinnability: during spinning, the full winding rate ≥ 97% is excellent, ≥ 95% and < 97% is good, ≥ 90% and < 95% is fair, and < 90% is poor; full winding rate (%) = (full winding production amount / total production amount) x 100%.

[0113] The spandex fibers provided in Examples 1-11 and Comparative Examples 1-4 are tested according to the above test methods, and the test results are shown in Table 1:

[0114] Table 1

[0115]

[0116] According to the data in Table 1, it can be seen that:

[0117] The easily dyeable composite spandex fibers provided in Examples 1-11 have excellent mechanical properties, heat resistance and dyeing performance; and the spandex fibers provided in Comparative Examples 1-4 cannot have excellent mechanical properties, heat resistance and dyeing performance.

[0118] The applicant states that the present application illustrates an easy-to-dye composite spandex fiber, its preparation method and application by the above-mentioned examples, but the present application is not limited to the above-mentioned examples, that is, it does not mean that the present application must rely on the above-mentioned examples to be implemented. The skilled in the art should understand that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A dyeable composite spandex fiber, characterized by, The dyeable composite spandex fiber has a sheath-core structure, comprising a sheath layer and a core layer; The material of the sheath layer comprises a first polyurethane-urea and a thermoplastic polyurethane; The material of the core layer comprises a second polyurethane-urea.

2. The dyeable composite spandex fiber according to claim 1, wherein, The mass percentage of the sheath layer in the dyeable composite spandex fiber is 20-80%.

3. The dyeable spandex fiber according to claim 1 or 2, wherein, The mass percentage of the first polyurethane-urea in the material of the sheath layer is 10-90%.

4. The dyeable spandex fiber according to any one of claims 1 to 3, characterized in that, The raw materials for preparing the first polyurethane-urea comprise a first polyol A, a first isocyanate A, a diamine chain extender A and an amine chain terminator A; Preferably, the raw materials for preparing the second polyurethane-urea comprise a first polyol B, a first isocyanate B, a diamine chain extender B and an amine chain terminator B; Preferably, the number average molecular weight of the first polyol A and the first polyol B is independently 1000-3000 g / mol; Preferably, the first polyol A and the first polyol B independently comprise any one or a combination of at least two of polytetramethylene ether glycol, polyethylene glycol or polypropylene glycol, further preferably polytetramethylene ether glycol; Preferably, the first isocyanate A and the first isocyanate B independently comprise any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate, further preferably diphenylmethane diisocyanate; Preferably, the diamine chain extender A and the diamine chain extender B are independently a diamine with a carbon atom number of 2-30; Preferably, the diamine with a carbon atom number of 2-30 comprises any one or a combination of at least two of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, methylpentanediamine, methylpropylenediamine, hexanediamine, xylylenediamine, phenylenediamine, diaminocyclohexane or hexamethylenediamine; Preferably, the amine chain terminator A and the amine chain terminator B independently comprise a primary amine with a carbon atom number of 2-20 and / or a tertiary amine-containing primary amine with a carbon atom number of 2-20; Preferably, the primary amine with a carbon atom number of 2-20 comprises any one or a combination of at least two of diethylamine, isopropylamine, n-butylamine, t-butylamine, hexylamine diethylamine, dimethylamine, di-n-butylamine, di-t-butylamine, diisobutylamine, diisopropylamine, diethylamine, dipropylamine or cyclohexylamine or ethanolamine; Preferably, the tertiary amine-containing primary amine with a carbon atom number of 2-20 comprises any one or a combination of at least two of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propanediamine or N,N-diethyl-1,3-propanediamine; Preferably, the amine chain terminator A comprises a primary amine with a carbon atom number of 2-20 and a tertiary amine-containing primary amine with a carbon atom number of 2-20; Preferably, the amine chain terminator B comprises a primary amine with a carbon atom number of 2-20.

5. The dyeable spandex fiber according to any one of claims 1 to 4, characterized in that, The mass percentage of the thermoplastic polyurethane in the material of the sheath layer is 10-90%.

6. The dyeable spandex fiber according to any one of claims 1 to 5, characterized in that, The Shore hardness of the thermoplastic polyurethane is 60-95A, preferably 75-85A.

7. The dyeable spandex fiber according to any one of claims 1 to 6, characterized in that, The raw materials for preparing the thermoplastic polyurethane include a second polyol, a second isocyanate and a diol chain extender; Preferably, the second polyol has a number average molecular weight of 800-3000 g / mol; Preferably, the second polyol includes polyethylene glycol and / or polypropylene glycol, further preferably polyethylene glycol; Preferably, the second isocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate, further preferably diphenylmethane diisocyanate; Preferably, the diol chain extender is a dihydric alcohol having 2-10 carbon atoms; Preferably, the dihydric alcohol having 2-10 carbon atoms includes any one or a combination of at least two of ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, methyl pentylene glycol, neopentyl glycol, methyl propylene glycol, hexylene glycol, heptylene glycol, octylene glycol or nonylene glycol.

8. The dyeable spandex fiber according to any one of claims 1 to 7, characterized in that, The material of the sheath further includes a dyeing assistant; Preferably, the dyeing assistant has a mass percentage content of 0.3-3% in the material of the sheath; Preferably, the dyeing assistant includes any one or a combination of at least two of an amine dyeing assistant, a (meth)acrylic dyeing assistant, a polyamide dyeing assistant, a polyurethane dyeing assistant, a sulfonate dyeing assistant, a carbonate dyeing assistant or a borate dyeing assistant; Preferably, the dyeing assistant includes any one or a combination of at least two of poly(methyl)acrylic acid diethylaminoethyl ester, sodium dibutylnaphthalene sulfonate, sodium carbonate or sodium borate.

9. A process for producing the dyeable composite spandex fiber according to any one of claims 1 to 8, characterized by, The preparation method includes the following steps: (1) mixing the first polyurethane-urea, the thermoplastic polyurethane and optionally the dyeing assistant to obtain a sheath spinning dope; and using the second polyurethane-urea as a core layer spinning dope; (2) spinning the sheath spinning dope and the core layer spinning dope obtained in step (1) through a spinneret sheath-core assembly to obtain the dyeable composite spandex fiber; Preferably, the spinning in step (2) is dry spinning.

10. A garment textile, characterized in that, The garment textile includes the dyeable composite spandex fiber according to any one of claims 1-7.

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