A kind of high resilience spandex fiber and preparation method thereof

Abstract

The present invention discloses a high-resilience spandex fiber, the main raw materials of which are: polyether polyol or polyester polyol, diisocyanate compound, chain extender and end-capping agent; the chain extender is lysine cyclodipeptide or ornithine cyclodipeptide. The present invention also discloses a preparation method of the above-mentioned high-resilience spandex fiber. The present invention uses the condensation product of two molecules of amino acids, lysine cyclodipeptide and ornithine cyclodipeptide, as chain extenders to improve the degree of hydrogen bonding in polyurethane fibers, form more hydrogen bond cross-linking points, and the prepared spandex fiber has higher resilience. The prepared high-resilience spandex fiber not only has good tensile elongation, but also has greater breaking strength. Compared with ordinary polyether-based spandex fibers, the breaking elongation strength of 70D high-resilience spandex fibers exceeds 140cN, and the strength at 300% elongation is greater than that of ordinary polyether-based spandex fibers, both exceeding 35cN.

Description

Technical Field

[0001] The invention belongs to the field of chemical materials and relates to bio-based spandex fiber and a preparation method thereof. Technical Background

[0002] Spandex, commonly known as Spandex internationally, is also known as polyurethane elastic fiber. It is a highly elastic fiber that was industrially produced in the 1950s. With the improvement of production technology and the promotion of application technology, the production and consumption of spandex have been strongly promoted, especially in recent years, which has ushered in the rapid development of spandex fiber production and consumption.

[0003] The structure of spandex fiber:

[0004] Spandex is the trade name of polyurethane elastic fiber. The macromolecular chain segments of polyurethane fiber contain polyurethane. The fiber has an amorphous structure and a low glass transition temperature. At room temperature, the flexible chain segments of the macromolecules are in a highly elastic state. This structural feature makes the fiber have a large extensibility of 400-800% under standard temperature and humidity.

[0005] If polyurethane is made into a homopolymer, the fiber is the same as ordinary fiber and has no elasticity. Spandex is a fiber made by block copolymerization. Its molecular structure contains both soft, non-crystalline low-molecular segments, such as polyester and polyether segments, and hard rigid segments, such as diisocyanate, which is crystalline and can produce transverse cross-linking. These two segments with different properties are connected in an inlaid manner, and the flexible segments have certain cross-linking to form a network structure. When the fiber is subjected to external force, the flexible segments are easily stretched and deformed due to the small interaction force between the molecular chains. This is the reason why spandex is easy to be stretched. On the other hand, due to the presence of rigid segments, the molecules will not slip when subjected to external forces, which gives it sufficient resilience. Furthermore, because a certain network structure is formed between the flexible segments, this structure allows the molecules to always maintain a certain relative position. Even if it is stretched tens of thousands of times, it can still have resilience like a rubber band.

[0006] Flexible segment:

[0007] The soft segment of polyurethane is generally composed of oligomer polyols. Oligomer polyols mainly include polyether polyols and polyether polyols. The soft segment has a relatively large content in polyurethane elastomers, and generally forms soft segment crystals with a glass transition temperature lower than room temperature.

[0008] The length of the soft segment molecular chain is longer than that of the hard segment, and the soft segment contains more hydrocarbon structures, which makes the soft segment in an amorphous state at room temperature. The chemical regularity of the soft segment phase, the main valence force of the macromolecular chain, the force between molecules and the flexibility of the macromolecular chain have a great influence on the low temperature resistance, crystallinity, mechanical properties, melting point and flexibility of polyurethane elastomers.

[0009] The influence of the soft segment on polyurethane elastomers or fibers is mainly manifested in: the type of soft segment, molecular weight (hydroxyl value) and functionality. Elastomers with polyester polyol as the soft segment have good heat resistance, relatively good tensile strength, tear strength, oil resistance and wear resistance. Elastomers with polyether polyol as the soft segment have good hydrolysis resistance, low soft segment glass transition temperature and good mildew resistance, but poor mechanical properties.

[0010] Polyols provide soft chain ends for polyurethane elastomers, and their physical properties are flexibility. Polyols in polyurethane elastomers are generally oligomer polyols, with functionalities of 2-3 and molecular weights of 400-6000, with 1000-3000 being the most commonly used. The lower the molecular weight of the soft segment, the higher the relative content of the hard segment.

[0011] Rigid segment:

[0012] The rigid segment (hard segment) is generally obtained by polymerization or cross-linking reaction of small molecule diols, small molecule diamines and diisocyanates, so the rigidity of the hard segment group is relatively large and the cohesive energy is relatively large. The carbamate group or urea group contained in the hard segment will form hydrogen bonds and easily form hard segment micro-regions.

[0013] In the manufactured polyurethane elastomer, the hard segment contains a certain proportion of hard segment phase. The hard segment phase contains more carbamate structures, urea structures, etc. The hard segment also has a great influence on the properties of polyurethane elastomers. The main reason is that the imino and carbonyl structures contained in the hard segment will form hydrogen bond structures, and the hydrogen bond structures will affect the crystallization of the hard segment and the microphase separation of the soft and hard segments. In addition, the hard segment phase has a large cohesive energy and will form a crystalline structure. These crystals are generally dispersed in the soft segment phase in the form of microcrystals, acting as crosslinking points. The factors that affect the cohesive energy of the hard segment are mainly: the type of isocyanate, the type of chain extender, and the mass fraction of the hard segment.

[0014] Microphase separation:

[0015] To obtain ultra-high elastic fibers, the soft segment must not easily enter the lattice formed by the hard segment, that is, the hard segment must have an increased polarity, and the hard segments form crystals through hydrogen bonds or strong polar bonds, while the soft segment must form an independent system with low polarity. The hard segment and the soft segment are two independent systems that do not interfere with each other. To achieve this goal, the soft segment and the hard segment need to be fully expanded respectively, making the hard segment harder and the soft segment softer, each performing its own function and "separating". Since the crystalline region and the non-crystalline region belong to the microstructure of the fiber, it is called "microphase separation". Microphase separation means that at room temperature, the hard segment microregion is not soluble in the soft segment, but distributed in the soft segment, playing a cross-linking role, which has a great impact on the performance of polyurethane products. It is the key to the ultra-high elasticity of spandex.

[0016] In addition to the crystallization of the hard segment, the main influencing factor of microphase separation is the self-assembly of hydrogen bonds between hard segments, which is also the main driving force. Most hard segments contain carbamate or allophanate, in which -NH is an electron-donating group and C=O is an electron-withdrawing group. The self-assembly of hydrogen bonds promotes the formation of hard segment micro-regions between hard segments, which plays the role of a skeleton in polyurethane and gives polyurethane excellent mechanical properties.

[0017] The soft and hard segment structure, molecular weight, soft and hard segment chain distribution, the difference in thermodynamic compatibility of the soft and hard segments, and the change in the overall molecular weight will all affect the hydrogen bonding in the polyurethane, thereby affecting the microphase separation in the fiber.

[0018] Hydrogen bonding:

[0019] In polyurethane, hydrogen bonding is ubiquitous and very important. It forms a physical cross-linking network that enhances the mechanical properties of polyurethane. The formation of hydrogen bonds between hard segments helps to form a microphase separation structure of polyurethane.

[0020] The -NH in carbamate (or allophanate) as an electron-donating group can form hydrogen bonds with electron-withdrawing carbonyl and ether bonds. The hydrogen bonding force is as follows:

[0021]

[0022] The magnitude of these hydrogen bonding forces is different. The strength of hydrogen bonding forces between carbamate-ether bonds (a), carbamate-ester bonds (b, c) and carbamate-carbamate bonds (d) are 23.6 Kj / mol, 25.6 Kj / mol and 46.5 Kj / mol respectively.

[0023] The influence of the flexible segment (soft segment) on the hydrogen bonding degree of polyurethane elastomer can be divided into two aspects: the soft segment content and the soft segment type. Polyester polyols contain ester groups. The carbonyl group in the ester group has a larger polarity and is more likely to form hydrogen bonds. Therefore, the carbonyl group in the ester group has a greater probability of forming hydrogen bonds than the ether group, that is, the hydrogen bonding degree of polyether polyurethane is lower than that of polyester polyurethane. When the soft segment content increases, the total hydrogen bonding degree will decrease due to the decrease in the relative content of the imino group on the hard segment that can form hydrogen bonds with the soft segment, and vice versa.

[0024] Chain Extender:

[0025] The main function of chain extenders is to connect short molecular chains, so that the molecular chains grow and the molecules are cross-linked. There are two commonly used chain extenders: one is polyol chain extenders, and the other is polyamine chain extenders. Diamine compounds such as: 3,3'-dichloro-4,4'-diphenylmethanediamine (MOCA), or a mixture of ethylenediamine and 1,2-propylenediamine, their chain extension conditions are relatively mild and are most widely used in industry. The most commonly used diol chain extenders are 1,4-butanediol (BDO), ethylene glycol (EG), 1,2-propylene glycol, etc., which have the advantages of mild reaction conditions, liquid at room temperature, and easy operation.

[0026] The influence of the hard segment on the hydrogen bonding degree of polyurethane elastomers is mainly reflected in the difference between the chain extenders being diamines or diols. When diamines are used as chain extenders, they form a urea structure containing two imino groups and one carbonyl group, and the imino groups and the carbonyl groups in the ether and ester groups can form hydrogen bonds. Therefore, when diamines are used as chain extenders, due to the relationship between the quantity and degree, the total hydrogen bonding degree of the elastomer is relatively increased, and it is easier to form hydrogen bonds and microphase separation. This has a great impact on the mechanical properties and crystallinity of the elastomer. When diols are used as chain extenders, an imino group and an ester group are formed. The number of imino groups is half that of the urea structure, the hydrogen bonding degree of the carbonyl and ether groups is relatively reduced, the total hydrogen bonding degree is reduced, and the mechanical properties of the elastomer are changed. (Song Chenglong, Research on Heat-Resistant Modification of Polyurethane for Elastic Fibers, Master's Thesis of South China University of Technology, 2017)

[0027] Patent CN201710663461.0 introduces a high-resilience spandex fiber and a preparation method thereof, which is prepared by only a conventional polymerization method, and the chain extender used is not disclosed.

[0028] CN201810477737.0 introduces a spinning solution and a preparation method thereof, as well as a method for preparing high-resilience spandex, which uses caprolactam diblocked isocyanate to enhance the crystalline area and molecular weight of the hard segment.

[0029]

[0030] The preparation method of high-resilience spandex fiber introduced in Chinese patent document CN101555638 is to prepolymerize oligomeric diols of different molecular weights in an organic solvent, and the chain extender used is a common diamine compound; the high-resilience spandex fiber improved by patents CN102277649 and CN101469463 is mainly improved by physical crosslinking and MDI chemical crosslinking methods. The side effect of this is that the degree of crosslinking is not easy to control and the viscosity of the spinning solution is unstable during storage.

[0031] The Chinese patent document CN201310375826.1 introduces a high resilience spandex fiber and a preparation method thereof, which uses a multifunctional amine (functionality>2) as a chain extender to increase the urea content and hydrogen bond content during the chain extension process, and the multifunctional amine used is diethylenetriamine. Modified attapulgite is also added during the preparation of the spandex fiber.

[0032] The preparation method of polyether high resilience spandex fiber introduced in Chinese patent document CN200810116701.6 adopts common fatty diamines as chain extenders, such as ethylenediamine, 2-methylpentanediamine, propylenediamine or cyclohexanediamine; and the end-capping agent is common monofunctional primary or secondary amines, such as dimethylamine, ethanolamine, etc.

[0033] A higher degree of hydrogen bonding forms more hydrogen bond crosslinking points, increasing the incompatibility between the soft and hard segments of the system, resulting in an increase in the degree of microphase separation, which increases the breaking strength of spandex and provides excellent mechanical properties. (You Gexin, Chen Xiri, Yang Bo, Zhou Xiuwen. Effect of soft segment molecular weight on the microphase separation degree and tensile properties of spandex, Engineering Plastics Applications, 2017, 45(12): 88-92). Summary of the invention

[0034] The technical problem to be solved by the present invention is to address the deficiencies of the prior art and to propose a new high-resilience spandex fiber, which can improve the degree of hydrogen bonding in polyurethane fibers and form more hydrogen bond cross-linking points.

[0035] Another technical problem to be solved by the present invention is to provide a method for preparing the aforementioned high resilience spandex fiber.

[0036] The technical problem to be solved by the present invention is achieved by the following technical solution. The present invention is a high-resilience spandex fiber, characterized in that the main raw materials of the high-resilience spandex fiber are: polyether polyol or polyester polyol, and diisocyanate compound, chain extender and end-capping agent;

[0037] The chain extender is a lysine cyclodipeptide or an ornithine cyclodipeptide, and its structure is as follows:

[0038]

[0039] The high resilience spandex fiber of the present invention has a further preferred technical solution: the polyether polyol is polytetrahydrofuran PTMG with a molecular weight of 1000-3000, and its structure is as follows:

[0040]

[0041] Wherein, n represents the degree of polymerization of PTMG, which is a natural number of 10-35.

[0042] The high resilience spandex fiber of the present invention has a further preferred technical solution: the polyester polyol is a polyhydroxyl-terminated polyester with a molecular weight of 1000-3000, and its structure is as follows:

[0043]

[0044] Wherein: R1 is one or more structures of -(CH2)2-, -(CH2)3-, -(CH2)6-, -(CH2)8-, -(CH2)9;

[0045] R2 is: -(CH2)2-, -(CH2)3-, -(CH2)6-, -(CH2)8-, -(CH2)9, -(CH2) 10 One or more structures; n is the degree of polymerization of the polyester, which is a natural number of 4-10.

[0046] A further preferred technical solution of the high resilience spandex fiber of the present invention is that the diisocyanate compound is diphenylmethane diisocyanate or toluene diisocyanate.

[0047] A further preferred technical solution of the high resilience spandex fiber of the present invention is that the amino acid as the end-capping agent is selected from: glycine, glutamic acid, sodium taurine, aspartic acid or alanine.

[0048] The present invention also provides a method for preparing the high resilience spandex fiber as described in any one of the above technical solutions, which is characterized in that the steps are as follows:

[0049] (1) Prepolymerization: In a reaction kettle filled with a certain amount of organic solvent N,N-dimethylacetamide (DMAc), 1 mol of polyester or polyether diol is prepared into a 30% concentration solution, and then 2.0-2.02 mol of diisocyanate compound is added while stirring, and prepolymerization is carried out at 40-45°C for 3-6 hours;

[0050] (2) Chain extension: Add 1 mol of chain extender into the reaction kettle to carry out chain extension reaction on the prepolymer prepared in step (1) at 40-45° C. for 2-3 hours;

[0051] (3) Capping: Add 0.1-0.15 mol of amino acid as a capping agent to cap the polymer prepared in step (2) at 40-45° C. for 2-3 hours;

[0052] (4) Ripening: The polyurethane solution prepared in step (3) is matured by continuously stirring at 37-45° C. for 28-30 hours.

[0053] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers.

[0054] The method for preparing the high-resilience spandex fiber of the present invention has a further preferred technical solution that the polyether diol is polytetrahydrofuran diol with a molecular weight of 1000-3000 or polyester diol with a molecular weight of 1000-3000.

[0055] The present invention uses lysine cyclodipeptide and ornithine cyclodipeptide as chain extenders to prepare high-resilience spandex fibers. Lysine cyclodipeptide is a diamine compound obtained by dehydration cyclization of two molecules of lysine, and its molecule has a six-membered ring structure containing two amide groups and two primary amines:

[0056]

[0057] When preparing polyurethane elastomers, lysine cyclodipeptide and ornithine cyclodipeptide are used as chain extenders, which can react with cyanate esters to produce cyclodipeptide diurea structures, introducing rigid and highly polar six-membered ring structures into the hard segment. At the same time, two amide groups that can form hydrogen bonds with ether bonds, ester groups, carbamate groups, and urea groups are also introduced, further increasing the rigidity of the hard segment and making the prepared polyurethane more susceptible to microphase separation; at the same time, when the soft segment is stretched and slips, its recovery force when it rebounds is greater:

[0058]

[0059] Hydrogen bonds of lysine cyclodipeptide diurea generated by lysine cyclodipeptide as chain extender (dashed line)

[0060] Similarly, the structural formula of ornithine cyclodipeptide is as follows:

[0061]

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. In the application number 202210893718.2 applied by the applicant, it is mainly involved that the chain extender amino acid of spandex fiber in the polymerization stage is lysine, and the end-capping agent is one or more of glycine, glutamic acid, sodium taurine, aspartic acid or alanine. The bio-based spandex fiber molecular chain prepared by this method has more anionic dye sites and is dyeable with cationic dyes. On this basis, the present invention goes a step further and uses the condensation product of two amino acids-dipeptides (lysine cyclodipeptide, ornithine cyclodipeptide) as a chain extender to increase the degree of hydrogen bonding in the polyurethane fiber, form more hydrogen bond cross-linking points, and the prepared spandex fiber has higher resilience.

[0064] 2. The chain extender used in the present invention is obtained by dehydration cyclization of amino acids, which is safer and more environmentally friendly. DETAILED DESCRIPTION

[0065] The following examples are provided to further illustrate the present invention, but the present invention is not limited thereto.

[0066] Example 1

[0067] (1) Prepolymerization: In a reaction kettle filled with 500 kg of N,N-dimethylacetamide (DMAc), 200 kg of PTMEG (polytetrahydrofuran, molecular weight 2000, hydroxyl value 56.1, produced by Shanxi Sanwei Group) was added, and then 50 kg of diphenylmethane diisocyanate (produced by BASF Chemical) was added while stirring, and prepolymerized at 40°C for 3 hours;

[0068] (2) Chain extension: 25.6 kg of chain extender lysine cyclodipeptide (produced by Sinopharm Group) was added to the reactor to carry out chain extension reaction on the prepolymer prepared in step (1) at 40° C. for 2 hours;

[0069] (3) End-capping: 13.3 kg of end-capping agent aspartic acid (produced by Shandong Ruiyuan Biotechnology Co., Ltd.) was added to end-cap the polymer prepared in step (2) at 40° C. for 2 hours.

[0070] (4) Ripening: The polyurethane solution prepared in step (3) was matured by continuous stirring at 45° C. for 28 hours. The system viscosity was measured to be 3700 poise.

[0071] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers, numbered 1#.

[0072] Example 2

[0073] (1) Prepolymerization: In a reaction kettle filled with 700 kg of N,N-dimethylacetamide (DMAc), 200 kg of PTMEG (polytetrahydrofuran, molecular weight 2300, hydroxyl value 48.8, produced by Shanxi Sanwei Group) was added, and then 43.5 kg of diphenylmethane diisocyanate (produced by BASF Chemical) was added while stirring, and prepolymerized at 40°C for 3 hours;

[0074] (2) Chain extension: 22.2 kg of chain extender ornithine cyclodipeptide (produced by Sinopharm Group) was added to the reactor to carry out chain extension reaction on the prepolymer prepared in step (1) at 40° C. for 2 hours;

[0075] (3) Capping: 10.5 kg of aspartic acid (produced by Shandong Ruiyuan Biotechnology Co., Ltd.), a capping agent, was added to cap the polymer prepared in step (2) at 40° C. for 2 hours.

[0076] (4) Ripening: The polyurethane solution prepared in step (3) was matured by continuous stirring at 45° C. for 28 hours. The system viscosity was measured to be 3450 poise.

[0077] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers, numbered 2#.

[0078] Example 3

[0079] (1) Prepolymerization: In a reactor containing 1000 kg DMAc, 428 kg of bio-based polyester diol 1011 (polyundecyl sebacate, hydroxyl value 37.4, molecular weight 3000. Produced by Nanjing Advanced Biomaterials and Process Equipment Research Institute Co., Ltd.), then add toluene diisocyanate while stirring T65N (a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, produced by Covestro) 49.6 kg, prepolymerized at 44 ° C for 6 hours;

[0080] (2) Chain extension: 35.5 kg of chain extender lysine cyclodipeptide (produced by Sinopharm Group) was added to the reactor to carry out chain extension reaction on the prepolymer prepared in step (1) at 45° C. for 2 hours;

[0081] (3) End-capping: 2.8 kg of taurine, an end-capping agent, was added to end-cap the polymer prepared in step (2) at 45° C. for 2 hours.

[0082] (4) Ripening: The bio-based polyurethane solution prepared in step (3) was matured by continuous stirring at 40° C. for 28 hours. The system viscosity was measured to be 4200 poise.

[0083] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers, numbered 3#.

[0084] Example 4

[0085] (1) Prepolymerization: In a reactor containing 700 kg of N,N-dimethylacetamide (DMAc), 400 kg of PTMEG (polytetrahydrofuran, molecular weight 2000, hydroxyl value 56.1, produced by Shanxi Sanwei Group) was added with stirring toluene diisocyanate. T65N (a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, produced by Covestro) 69.6 kg, prepolymerized at 40°C for 3 hours;

[0086] (2) Chain extension: 45 kg of chain extender ornithine cyclodipeptide (produced by Sinopharm Group) was added to the reactor to carry out chain extension reaction on the prepolymer prepared in step (1) at 40° C. for 2 hours;

[0087] (3) Capping: 4.5 kg of aspartic acid, a capping agent, was added to cap the polymer prepared in step (2) at 40° C. for 2 hours.

[0088] (4) Ripening: The polyurethane solution prepared in step (3) was matured by continuous stirring at 45° C. for 28 hours. The system viscosity was measured to be 3450 poise.

[0089] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers, numbered 4#.

[0090] Example 5

[0091] (1) Prepolymerization: In a reactor containing 1000 kg of DMAc, 540 kg of bio-based polyester polyol was converted into bio-based polyester diol. 1111 (polyundecanediol 11-14-diol, hydroxyl value 41.6, molecular weight 2700), then add toluene diisocyanate while stirring T65N (a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, produced by Covestro) 70 kg, prepolymerized at 44 ° C for 6 hours;

[0092] (2) Chain extension: 45.1 kg of chain extender lysine cyclodipeptide (produced by Sinopharm Group) was added to the reactor to carry out chain extension reaction on the prepolymer prepared in step (1) at 45° C. for 2 hours;

[0093] (3) Capping: 5.6 kg of aspartic acid, a capping agent, was added to cap the polymer prepared in step (2) at 45° C. for 2 hours.

[0094] (4) Ripening: The bio-based polyurethane solution prepared in step (3) was matured by continuous stirring at 40° C. for 28 hours. The system viscosity was measured to be 5600 poise.

[0095] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers, numbered 5#.

[0096] Example 6

[0097] (1) Prepolymerization: In a reactor containing 1000 kg of DMAc, 540 kg of bio-based polyester polyol was converted into bio-based polyester diol. 2111 (polyundecanediol / sebacate, hydroxyl value 38.7, molecular weight 2900, produced by Nanjing Advanced Biomaterials and Process Equipment Research Institute Co., Ltd.), then add toluene diisocyanate while stirring T65 N 60kg, prepolymerized at 44°C for 6 hours;

[0098] (2) Chain extension: 42.1 kg of chain extender ornithine cyclodipeptide (produced by Sinopharm Group) was added to the reactor to carry out chain extension reaction on the prepolymer prepared in step (1) at 45° C. for 2 hours;

[0099] (3) Capping: 3.6 kg of taurine, a capping agent, was added to cap the polymer prepared in step (2) at 45° C. for 2 hours.

[0100] (4) Ripening: The bio-based polyurethane solution prepared in step (3) was matured by continuous stirring at 40° C. for 28 hours. The system viscosity was measured to be 6520 poise.

[0101] (5) Spinning: The spinning solution prepared in step (4) is spun through operations such as discharging, spraying, stretching, false twisting and oiling to produce spandex fibers, numbered 6#.

[0102] The comparative example is as follows:

[0103] Comparison sample 1#

[0104] This example is a comparative example of preparing spandex fiber with conventional materials. The experimental method is the same as that of Example 3, except that the chain extender used is ethylenediamine and the end-capping agent is taurine. Step (4) The viscosity of the spinning solution after aging is 4680 poise.

[0105] The prepared spandex fiber number: comparison sample 1#.

[0106] Comparison sample 2#

[0107] This example is a comparative example of preparing spandex fiber with conventional materials. The experimental method is the same as that of Example 3, except that PTMEG1500 (polytetrahydrofuran, produced by Dow Chemical) is used, the chain extender is 1,2-propylenediamine, and the end-capping agent is taurine. Step (4) The viscosity of the spinning solution after aging is 4500 poise.

[0108] The prepared spandex fiber number: comparison sample 2#.

[0109] Bio-Spandex Fiber Performance Test

[0110] The bio-based spandex fiber samples prepared in the examples were tested according to the standards FZ / T 50006-2013 (Test method for tensile properties of spandex fiber) and FZ / T 50007-2012 (Test method for elasticity of spandex yarn). The biocarbon content of the prepared spandex fiber was tested according to the method of the standard GB / T 39715.2-2021 (Determination of bio-based content of plastics). The relevant results are shown in Table 1.

[0111] Table 1. Mechanical properties test of spandex fiber

[0112]

[0113]

[0114] * In Table 1, TEN is the breaking strength; ELO (%) is the breaking elongation; TM2 is the stress of the wire when the wire recovers to 200% after the 5th stretching.

[0115] As can be seen from Table 1 above, the prepared high resilience spandex fiber not only has good tensile elongation, but also has greater breaking strength. Compared with ordinary polyether-based spandex fiber, the breaking elongation strength of 70D high resilience spandex fiber exceeds 140cN, and the strength at 300% elongation is greater than that of ordinary polyether-based spandex fiber, both exceeding 35cN.

Claims

1. A high resilience spandex fiber, characterized in that: The main raw materials of high resilience spandex fiber are: polyether polyol or polyester polyol, as well as diisocyanate compounds, chain extenders and end-capping agents; The chain extender is a lysine cyclodipeptide or an ornithine cyclodipeptide, and its structure is as follows: ； The polyether polyol is polytetrahydrofuran (PTMG) with a molecular weight of 1000-3000, and its structure is as follows: ； Wherein, n represents the degree of polymerization of PTMG, which is a natural number of 10-35; The polyester polyol is a polyhydroxyl-terminated polyester with a molecular weight of 1000-3000, and its structure is as follows: ； Wherein: R1 is one or more structures selected from -(CH2)2-, -(CH2)3-, -(CH2)6-, -(CH2)8-, -(CH2)9; R2 is: -(CH2)2-, -(CH2)3-, -(CH2)6-, -(CH2)8-, -(CH2)9-, -(CH2) 10 - one or more structures; n is the degree of polymerization of polyester, which is a natural number of 4-10; The diisocyanate compound is diphenylmethane diisocyanate or toluene diisocyanate; The capping agent is selected from: glycine, glutamic acid, sodium taurine, aspartic acid or alanine.

2. A method for preparing high resilience spandex fiber as claimed in claim 1, characterized in that: The steps are as follows: (1) Prepolymerization: In a reaction kettle filled with a certain amount of organic solvent N,N-dimethylacetamide (DMAc), 1 mol of polyester or polyether diol is prepared into a 30% concentration solution, and then 2.0-2.02 mol of diisocyanate compound is added while stirring, and prepolymerization is carried out at 40-45°C for 3-6 hours; (2) Chain extension: Add 1 mol of chain extender into the reaction kettle to carry out chain extension reaction on the prepolymer prepared in step (1) at 40-45° C. for 2-3 hours; (3) End-capping: Add 0.1-0.15 mol of an end-capping agent to end-cap the polymer prepared in step (2) at 40-45° C. for 2-3 hours; (4) Ripening: Ripening the polyurethane solution prepared in step (3) at 37-45° C. with continuous stirring for 28-30 hours; (5) Spinning: The spinning solution prepared in step (4) is spun through discharge, spraying, stretching, false twisting and oiling operations to produce spandex fibers.

3. The method for preparing high resilience spandex fiber according to claim 2, characterized in that: The polyether diol is polytetrahydrofuran diol with a molecular weight of 1000-3000, and the polyester diol is polyester diol with a molecular weight of 1000-3000.

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