High-resilience spandex fiber fabric and preparation method thereof
By constructing a three-dimensional chemical cross-linking network and a surface cross-linking coating inside the spandex fiber, combined with an interface transition layer, the problem of decreased elasticity of spandex fiber during long-term use was solved, resulting in spandex fiber fabrics with high resilience and durability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANTOU WANLIHUI UNDERWEAR CO LTD
- Filing Date
- 2026-03-20
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional spandex fibers experience a decrease in elasticity recovery and increased stress relaxation under long-term dynamic stretching and humid washing conditions, resulting in fabrics that become loose, deformed, wrinkled, and lose elasticity quickly, making it difficult to meet the long-term stable elasticity requirements of high-end close-fitting clothing and professional sports equipment.
A three-dimensional chemical cross-linked network is constructed inside the spandex fiber using swelling and penetration technology, and a three-dimensional cross-linked elastic coating network is formed on the fabric surface. Combined with citric acid and sodium carboxymethyl cellulose, a stable interfacial transition layer is constructed, which synergistically improves the elastic recovery rate and wash resistance of the spandex fiber.
It significantly enhances the elastic recovery rate of fibers, improves the washability and tensile durability of the fabric, and ensures that the fabric can maintain good elastic recovery performance after repeated stretching and washing.
Smart Images
Figure CN122169356A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of spandex fiber technology, specifically to a high-resilience spandex fiber fabric and its preparation method. Background Technology
[0002] Spandex fiber (polyurethane fiber), a high-performance elastic fiber with a core of soft and hard segment block copolymer structure, has become an indispensable key material in the modern textile industry due to its ultra-high elongation at break and excellent elastic recovery performance. It is widely used in sportswear, underwear, socks, swimwear, medical protective gear, functional home textiles, and industrial elastic textiles, serving as a core component for improving fabric fit, freedom of movement, and wearing experience. As the textile consumer market upgrades towards high-end, functional, and durable products, consumers are placing increasingly stringent demands on the long-term comfort, shape stability, and lifespan of fabrics. Traditional spandex fiber has gradually revealed its performance shortcomings during actual use and repeated washing. Under long-term dynamic stretching, stress, and humid washing conditions, spandex molecular chains are prone to slippage, disorientation, and structural relaxation, leading to a decrease in fabric elastic recovery, increased stress relaxation, and insufficient wash resistance. This results in problems such as fabric loosening, deformation, wrinkling, and rapid elasticity loss, making it difficult to meet the long-term stable elasticity requirements of high-end underwear, professional sports equipment, and medical elastic products. Against this backdrop, how to significantly improve the elastic recovery rate, stress relaxation resistance, and washability of spandex fibers has become the core technical direction for the modification of spandex materials and the upgrading of elastic textiles, and is also a key technical issue that the industry urgently needs to address. Summary of the Invention
[0003] The purpose of this invention is to provide a high-resilience spandex fiber fabric and its preparation method, so as to solve the technical problems mentioned in the background art.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] A method for preparing a high-resilience spandex fiber fabric includes the following steps:
[0006] 1) A prepolymer was synthesized by reacting polytetrahydrofurandiol, dimethylolpropionic acid, isophorone diisocyanate and dibutyltin dilaurate; triethylamine was added for neutralization, and amino silicone oil was added for chain extension reaction; emulsification and dispersion were carried out, and ethylenediamine was added for chain extension to obtain an aqueous polyurethane-silicone composite emulsion.
[0007] 2) Polyether-type spandex fibers were swollen and impregnated using trimethylolpropane triglycidyl ether and dibutyltin dilaurate. After removal, they were dried and heat-cured in sequence to obtain cross-linked modified spandex fibers.
[0008] 3) Cross-linked modified spandex fiber is used as elastic yarn and nylon filament is woven together, and after relaxation, elastic fabric greige is obtained.
[0009] 4) After mixing sodium carboxymethyl cellulose with citric acid, add it to the mixture composed of the aqueous polyurethane-silicone composite emulsion and methyl ethyl ketone oxime-terminated hexamethylene diisocyanate trimer to obtain an elastic finishing liquid;
[0010] 5) The elastic fabric is impregnated in the elastic finishing liquid, and then pre-dried and cured to obtain a high-resilience spandex fiber fabric.
[0011] In the technical solution of this invention, the elasticity of spandex fiber fabric is improved in the following aspects: (1) The elasticity of spandex fiber comes from the reversible deformation of the soft segment in the polyurethane molecular chain. However, when the fiber is stretched significantly, irreversible chain slip will occur between the soft segment molecular chains, resulting in the fiber not being able to fully return to its original state, which manifests as a decrease in elastic recovery rate and an increase in stress relaxation. The swelling penetration crosslinking modification method adopted in this invention is as follows: DMF / ethanol mixed solvent is used as a controllable swelling carrier. DMF is used as a good solvent for polyurethane to moderately swell the fiber, increase the molecular chain spacing to form a molecular-level diffusion channel, and ethanol is used as a diluent to prevent the fiber from swelling or dissolving excessively. After the trifunctional epoxy crosslinking agent trimethylolpropane triglycidyl ether penetrates into the fiber through this channel, its three epoxy groups undergo nucleophilic ring-opening addition reaction with the secondary amine group in the polyurethane molecular chain, and ring-opening addition reaction with hydroxyl group under the catalysis of dibutyltin dilaurate Lewis acid to form ether bond. Since each crosslinking agent molecule can simultaneously connect two to three polyurethane molecular chains, a three-dimensional chemical crosslinking network is gradually constructed inside the fiber, with the crosslinking agent as nodes and the polyurethane molecular chains as the network framework. This crosslinking network anchors the originally freely sliding soft segments to the network nodes at the molecular level. When external force deforms the fiber, the crosslinking network stores elastic deformation energy. After the external force is removed, the elastic recoil force in the network drives the molecular chains to return to their initial conformation, fundamentally inhibiting the irreversible slippage of molecular chains under large deformation. The subsequent drying process ensures that the solvent is removed gently and orderly without damaging the fiber microstructure, allowing the residual epoxy groups to complete the final crosslinking during the thermosetting stage, forming a dense, uniform, and thermodynamically stable three-dimensional network structure. It should be noted that the amount of crosslinking agent added exceeds the total amount of active hydrogen that can directly participate in the reaction inside the fiber. In addition, there is a concentration gradient from the outside to the inside during the swelling and penetration process. The concentration of crosslinking agent on the outer surface of the fiber is always higher than that in the deeper layers. Therefore, after thermosetting, the fiber surface still retains a certain density of unreacted epoxy groups. These residual epoxy groups on the surface can serve as chemical anchoring sites for the subsequent citric acid interfacial bridging reaction. (2) An elastic coating network formed by baking and cross-linking curing of waterborne polyurethane-silicone composite emulsion is applied to the surface of the fabric. During the baking stage, the butanone oxime-terminated isocyanate cross-linking agent is thermally deactivated at high temperature to release active -NCO groups, which react with -OH and -NH groups on the polyurethane molecular chain of the coating to generate urethane bonds and urea bonds, thus constructing a three-dimensional cross-linked elastic network inside the coating. This coating is like a polymer film with elastic recovery function covering the surface of the fabric fibers and yarns. When the fabric is stretched, it deforms synchronously with the fibers and stores elastic energy. After the external force is removed, its own elastic recoil force is transmitted to the fabric skeleton through the fiber-coating interface, which is superimposed with the recovery force of the cross-linked network inside the fiber, and synergistically drives the fabric to return to its original state. The introduction of silicone segments in the coating gives the coating flexibility and surface smoothness, so that the coating can be repeatedly stretched and recovered with the fabric without cracking.
[0012] Preferably, in step 1), the mass ratio of polytetrahydrofuran diol to dimethylolpropionic acid is 100:(5-8).
[0013] Preferably, in step 1), the mass ratio of polytetrahydrofuran diol to isophorone diisocyanate is 100:(40-50).
[0014] Preferably, in step 2), the mass ratio of polyether-type spandex fiber to trimethylolpropane triglycidyl ether is 5:(4-6).
[0015] Preferably, in step 3), the mass ratio of cross-linked modified spandex fiber as elastic yarn to nylon filament is 2:(7-9).
[0016] Preferably, in step 4), the mass ratio of sodium carboxymethyl cellulose to citric acid is 5:(10-14).
[0017] During the experiment, it was found that after introducing a three-dimensional epoxy crosslinking network inside the fiber, a large number of polar groups on the fiber surface were consumed. At the same time, the epoxy curing products remaining on the fiber surface reduced the fiber surface energy and increased hydrophobicity. This resulted in a significant decrease in the wetting and spreading ability of the subsequent aqueous finishing liquid on this hydrophobic surface, and insufficient interfacial bonding between the coating and the fiber. After repeated stretching-recovery cycles and multiple water washings, the coating gradually peeled off, making it difficult to maintain the synergistic effect of the above two aspects. To address this problem, this invention introduces citric acid and sodium carboxymethyl cellulose into the finishing solution. Citric acid is a small-molecule multifunctional bridging agent containing three carboxyl groups. During the baking stage, its carboxyl groups undergo esterification and ring-opening reactions with the residual epoxy groups intentionally retained on the fiber surface in step one to form covalent ester bonds (the carboxyl groups and epoxy groups undergo esterification and ring-opening reactions at high temperatures to form β-hydroxy ester structures), covalently anchoring the citric acid molecules to the fiber surface. Simultaneously, its remaining carboxyl and hydroxyl groups form hydrogen bonds with the polar groups in the coating matrix, achieving covalent bridging between the fiber and the coating. Sodium carboxymethyl cellulose is a macromolecular flexible chain interface compatibilizer. Its densely packed carboxyl and hydroxyl groups form numerous hydrogen bonds with the fiber surface and the coating matrix, respectively. The flexible long chains also generate physical entanglement with the coating polymer, thickening and strengthening the interfacial transition layer. Citric acid provides covalent anchoring points for chemical bonding, while sodium carboxymethyl cellulose provides hydrogen bond networks and molecular chain entanglement for physical bonding. Together, they construct a stable interfacial transition layer that combines chemical bonding and physical entanglement, fundamentally solving the interfacial compatibility issues mentioned above. This allows the cross-linked network inside the fiber and the elastic coating on the surface to coordinate and perform elastic recovery functions, significantly improving the fabric's resilience and washability.
[0018] Preferably, in step 4), the mass ratio of the aqueous polyurethane-silicone composite emulsion to the butanone oxime-terminated hexamethylene diisocyanate trimer is 100:(2-5).
[0019] A high-resilience spandex fiber fabric is prepared by the above method.
[0020] Compared with the prior art, the beneficial effects of the present invention are:
[0021] 1. By constructing a three-dimensional chemical cross-linked network inside the spandex fiber through swelling and infiltration technology, the polyurethane molecular chains are anchored, fundamentally inhibiting irreversible chain slippage under large deformation and significantly enhancing the fiber's elastic recovery rate;
[0022] 2. A three-dimensional cross-linked elastic coating network is formed on the surface of the fabric. This coating can deform synchronously with the fiber and store elastic energy. Its shrinkage force is superimposed with the recovery force of the cross-linked network inside the fiber, which synergistically drives the fabric to quickly return to its original shape.
[0023] 3. To address the issue of poor adhesion between modified fibers and the coating, citric acid and sodium carboxymethyl cellulose are introduced to construct a stable interfacial transition layer, enabling the internal and external elastic systems to work in a long-lasting and coordinated manner, significantly improving the fabric's washability and tensile durability. Attached Figure Description
[0024] Figure 1 This is a low-magnification SEM image of the high-resilience spandex fiber fabric prepared in Example 1 of the present invention.
[0025] Figure 2 This is a medium-magnification SEM image of the high-resilience spandex fiber fabric prepared in Example 1 of the present invention.
[0026] Figure 3 This is a high-magnification SEM image of the high-resilience spandex fiber fabric prepared in Example 1 of the present invention.
[0027] Figure 4 The image shows the XRD pattern of the high-resilience spandex fiber fabric prepared in Example 1 of this invention. Detailed Implementation
[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0029] Example 1
[0030] A method for preparing a high-resilience spandex fiber fabric includes the following steps:
[0031] Step 1: In a 500 mL four-necked flask equipped with a mechanical stirrer, thermometer, condenser, and nitrogen delivery tube, add 100.0 g of polytetrahydrofuran diol (PTMG, molecular weight 1000, hydroxyl value 112 mg KOH / g). Dehydrate at 110 °C and a vacuum of -0.09 MPa for 2 h, then cool to 80 °C for later use. In another container, add 7.0 g of dimethylolpropionic acid (DMPA) to 7.0 g of N-methylpyrrolidone (NMP) and stir at 60 °C until completely dissolved. Add the DMPA / NMP solution to the four-necked flask, then add 48.0 g of isophorone diisocyanate (IPDI) and 0.05 g of dibutyltin dilaurate (DBTDL) sequentially. React at 80 °C for 2.5 h under nitrogen protection. Stop the reaction when the -NCO content drops to approximately 2.65 wt% by di-n-butylamine titration. The temperature was lowered to 50℃, and 5.0 g of triethylamine (TEA) was added for neutralization for 15 min. Then, 11.1 g of amino silicone oil (ammonia value 0.45 mmol / g) was slowly added dropwise over a period of at least 15 min, and the chain extension reaction was carried out at 50℃ for 30 min. The stirring speed was increased to 2500 rpm, and 414 g of deionized water was slowly added for emulsification and dispersion. After emulsification, the stirring speed was reduced to 800 rpm, and 2.85 g of ethylenediamine was slowly added dropwise (completed over approximately 5 min). The stirring was continued for 20 min to complete the aqueous phase chain extension, yielding an aqueous polyurethane-organic silicone composite emulsion.
[0032] Step 2: Add 5.5g of trimethylolpropane triglycidyl ether (TMP-TGE) and 0.1g of dibutyltin dilaurate to a mixed solvent consisting of 25mL of N,N-dimethylformamide (DMF) and 75mL of anhydrous ethanol (DMF:ethanol volume ratio = 1:3). Stir at room temperature for 25 minutes until completely dissolved to obtain a swelling crosslinking solution. Immerse 5.0g of polyether-type spandex fiber (40D) in the swelling crosslinking solution and treat it at 48℃ for 45 minutes, gently turning the fiber every 10 minutes during the treatment. Remove the fiber and dry it in three stages: first, pre-dry at 60℃ for 12 minutes, then dry at 102℃ for 18 minutes, and finally heat-cur at 130℃ for 30 minutes to obtain crosslinked modified spandex fiber.
[0033] Step 3: Cross-linked modified spandex fiber is used as the elastic yarn and woven with nylon filament (70D / 24F) on a warp knitting machine according to the warp knitting structure. The feed rate is controlled so that the mass ratio of cross-linked modified spandex fiber to nylon filament in the finished fabric is approximately 2:8.5. After weaving, the fabric is laid flat and relaxed for 12 hours under no tension to obtain the elastic fabric greige.
[0034] Step 4: Dissolve 0.5g of sodium carboxymethyl cellulose (CMC-Na, degree of substitution 0.9, viscosity-average molecular weight 100,000) in 30g of deionized water, stir at room temperature for 40min until completely dissolved, then add 1.3g of citric acid and stir for 5min until dissolved to obtain a CMC-Na / citric acid aqueous solution. Separately, take 100.0g of waterborne polyurethane-silicone composite emulsion, add 2.4g of butanone oxime-terminated hexamethylene diisocyanate trimer (effective -NCO content approximately 12wt%), and stir for 10min to mix thoroughly. Slowly pour the CMC-Na / citric acid aqueous solution into the emulsion mixture and stir thoroughly. Slowly add 5wt% sodium bicarbonate aqueous solution to adjust the pH to 4.5. Add deionized water to adjust the total amount of finishing solution to 150g, and stir thoroughly to obtain an elastic finishing solution.
[0035] Step 5: Impregnate the elastic fabric with an elastic finishing liquid using a two-dip, two-ply process, with a roll-off rate of 78%. Pre-dry at 85℃ for 4 minutes, then bake at 160℃ for 2 minutes. Remove and allow to cool naturally to room temperature to obtain a high-resilience spandex fiber fabric.
[0036] Example 2
[0037] A method for preparing a high-resilience spandex fiber fabric includes the following steps:
[0038] Step 1: In a 500 mL four-necked flask equipped with a mechanical stirrer, thermometer, condenser, and nitrogen delivery tube, add 100.0 g of polytetrahydrofuran diol (PTMG, molecular weight 1000, hydroxyl value 112 mg KOH / g). Dehydrate at 110 °C and a vacuum of -0.09 MPa for 2 h, then cool to 80 °C for later use. In another container, add 6.0 g of dimethylolpropionic acid (DMPA) to 7.0 g of N-methylpyrrolidone (NMP) and stir at 60 °C until completely dissolved. Add the DMPA / NMP solution to the four-necked flask, then add 42.0 g of isophorone diisocyanate (IPDI) and 0.05 g of dibutyltin dilaurate (DBTDL) sequentially. React at 80 °C for 2.5 h under nitrogen protection. Stop the reaction when the -NCO content drops to approximately 2.65 wt% by di-n-butylamine titration. The temperature was lowered to 50℃, and 5.0 g of triethylamine (TEA) was added for neutralization for 15 min. Then, 11.1 g of amino silicone oil (ammonia value 0.45 mmol / g) was slowly added dropwise over a period of at least 15 min, and the chain extension reaction was carried out at 50℃ for 30 min. The stirring speed was increased to 2500 rpm, and 414 g of deionized water was slowly added for emulsification and dispersion. After emulsification, the stirring speed was reduced to 800 rpm, and 2.85 g of ethylenediamine was slowly added dropwise (completed over approximately 5 min). The stirring was continued for 20 min to complete the aqueous phase chain extension, yielding an aqueous polyurethane-organic silicone composite emulsion.
[0039] Step 2: Add 4.5g of trimethylolpropane triglycidyl ether (TMP-TGE) and 0.1g of dibutyltin dilaurate to a mixed solvent consisting of 25mL of N,N-dimethylformamide (DMF) and 75mL of anhydrous ethanol (DMF:ethanol volume ratio = 1:3). Stir at room temperature for 25 minutes until completely dissolved to obtain a swelling crosslinking solution. Immerse 5.0g of polyether-type spandex fiber (40D) in the swelling crosslinking solution and treat it at 48℃ for 45 minutes, gently turning the fiber every 10 minutes during the treatment. Remove the fiber and dry it in three stages: first, pre-dry at 60℃ for 12 minutes, then dry at 102℃ for 18 minutes, and finally heat-cur at 130℃ for 30 minutes to obtain crosslinked modified spandex fiber.
[0040] Step 3: Cross-linked modified spandex fiber is used as the elastic yarn and woven with nylon filament (70D / 24F) on a warp knitting machine according to the warp knitting structure. The feed rate is controlled so that the mass ratio of cross-linked modified spandex fiber to nylon filament in the finished fabric is approximately 2:7.5. After weaving, the fabric is laid flat and relaxed for 12 hours under no tension to obtain the elastic fabric greige.
[0041] Step 4: Dissolve 0.5g of sodium carboxymethyl cellulose (CMC-Na, degree of substitution 0.9, viscosity-average molecular weight 100,000) in 30g of deionized water, stir at room temperature for 40min until completely dissolved, then add 1.1g of citric acid and stir for 5min until dissolved to obtain a CMC-Na / citric acid aqueous solution. Separately, take 100.0g of waterborne polyurethane-silicone composite emulsion, add 2.4g of butanone oxime-terminated hexamethylene diisocyanate trimer (effective -NCO content approximately 12wt%), and stir for 10min to mix thoroughly. Slowly pour the CMC-Na / citric acid aqueous solution into the emulsion mixture and stir thoroughly. Adjust the pH to 4.5 by slowly adding 5wt% sodium bicarbonate aqueous solution. Add deionized water to adjust the total amount of finishing solution to 150g, and stir thoroughly to obtain an elastic finishing solution.
[0042] Step 5: Impregnate the elastic fabric with an elastic finishing liquid using a two-dip, two-ply process, with a roll-off rate of 78%. Pre-dry at 85℃ for 4 minutes, then bake at 160℃ for 2 minutes. Remove and allow to cool naturally to room temperature to obtain a high-resilience spandex fiber fabric.
[0043] Example 3
[0044] A method for preparing a high-resilience spandex fiber fabric includes the following steps:
[0045] Step 1: In a 500 mL four-necked flask equipped with a mechanical stirrer, thermometer, condenser, and nitrogen delivery tube, add 100.0 g of polytetrahydrofuran diol (PTMG, molecular weight 1000, hydroxyl value 112 mg KOH / g). Dehydrate at 110 °C and a vacuum of -0.09 MPa for 2 h, then cool to 80 °C for later use. In another container, add 6.5 g of dimethylolpropionic acid (DMPA) to 7.0 g of N-methylpyrrolidone (NMP) and stir at 60 °C until completely dissolved. Add the DMPA / NMP solution to the four-necked flask, then add 45.0 g of isophorone diisocyanate (IPDI) and 0.05 g of dibutyltin dilaurate (DBTDL) sequentially. React at 80 °C for 2.5 h under nitrogen protection. Stop the reaction when the -NCO content drops to approximately 2.65 wt% by di-n-butylamine titration. The temperature was lowered to 50℃, and 5.0 g of triethylamine (TEA) was added for neutralization for 15 min. Then, 11.1 g of amino silicone oil (ammonia value 0.45 mmol / g) was slowly added dropwise over a period of at least 15 min, and the chain extension reaction was carried out at 50℃ for 30 min. The stirring speed was increased to 2500 rpm, and 414 g of deionized water was slowly added for emulsification and dispersion. After emulsification, the stirring speed was reduced to 800 rpm, and 2.85 g of ethylenediamine was slowly added dropwise (completed over approximately 5 min). The stirring was continued for 20 min to complete the aqueous phase chain extension, yielding an aqueous polyurethane-organic silicone composite emulsion.
[0046] Step 2: Add 5.0 g of trimethylolpropane triglycidyl ether (TMP-TGE) and 0.1 g of dibutyltin dilaurate to a mixed solvent consisting of 25 mL of N,N-dimethylformamide (DMF) and 75 mL of anhydrous ethanol (DMF:ethanol volume ratio = 1:3). Stir at room temperature for 25 min until completely dissolved to obtain a swelling crosslinking solution. Immerse 5.0 g of polyether-type spandex fiber (40D) in the swelling crosslinking solution and treat it at 48℃ for 45 min, gently turning the fiber once every 10 min during the treatment. Remove the fiber and dry it in three stages: first pre-dry at 60℃ for 12 min, then dry at 102℃ for 18 min, and finally heat-cur at 130℃ for 30 min to obtain crosslinked modified spandex fiber.
[0047] Step 3: Cross-linked modified spandex fiber is used as the elastic yarn and woven with nylon filament (70D / 24F) on a warp knitting machine according to the warp knitting structure. The feeding is controlled so that the mass ratio of cross-linked modified spandex fiber to nylon filament in the finished fabric is approximately 2:8. After weaving, the fabric is laid flat and relaxed for 12 hours under no tension to obtain the elastic fabric greige.
[0048] Step 4: Dissolve 0.5g of sodium carboxymethyl cellulose (CMC-Na, degree of substitution 0.9, viscosity-average molecular weight 100,000) in 30g of deionized water, stir at room temperature for 40min until completely dissolved, then add 1.2g of citric acid and stir for 5min until dissolved to obtain a CMC-Na / citric acid aqueous solution. Separately, take 100.0g of waterborne polyurethane-silicone composite emulsion, add 2.4g of butanone oxime-terminated hexamethylene diisocyanate trimer (effective -NCO content approximately 12wt%), and stir for 10min to mix thoroughly. Slowly pour the CMC-Na / citric acid aqueous solution into the emulsion mixture and stir thoroughly. Slowly add 5wt% sodium bicarbonate aqueous solution to adjust the pH to 4.5. Add deionized water to adjust the total amount of finishing solution to 150g, and stir thoroughly to obtain an elastic finishing solution.
[0049] Step 5: Impregnate the elastic fabric with an elastic finishing liquid using a two-dip, two-ply process, with a roll-off rate of 78%. Pre-dry at 85℃ for 4 minutes, then bake at 160℃ for 2 minutes. Remove and allow to cool naturally to room temperature to obtain a high-resilience spandex fiber fabric.
[0050] Example 4
[0051] A method for preparing a high-resilience spandex fiber fabric includes the following steps:
[0052] Step 1: In a 500 mL four-necked flask equipped with a mechanical stirrer, thermometer, condenser, and nitrogen delivery tube, add 100.0 g of polytetrahydrofuran diol (PTMG, molecular weight 1000, hydroxyl value 112 mg KOH / g). Dehydrate at 110 °C and a vacuum of -0.09 MPa for 2 h, then cool to 80 °C for later use. In another container, add 8.0 g of dimethylolpropionic acid (DMPA) to 7.0 g of N-methylpyrrolidone (NMP) and stir at 60 °C until completely dissolved. Add the DMPA / NMP solution to the four-necked flask, then add 50.0 g of isophorone diisocyanate (IPDI) and 0.05 g of dibutyltin dilaurate (DBTDL) sequentially. React at 80 °C for 2.5 h under nitrogen protection. Stop the reaction when the -NCO content drops to approximately 2.65 wt% by di-n-butylamine titration. The temperature was lowered to 50℃, and 5.0 g of triethylamine (TEA) was added for neutralization for 15 min. Then, 11.1 g of amino silicone oil (ammonia value 0.45 mmol / g) was slowly added dropwise over a period of at least 15 min, and the chain extension reaction was carried out at 50℃ for 30 min. The stirring speed was increased to 2500 rpm, and 414 g of deionized water was slowly added for emulsification and dispersion. After emulsification, the stirring speed was reduced to 800 rpm, and 2.85 g of ethylenediamine was slowly added dropwise (completed over approximately 5 min). The stirring was continued for 20 min to complete the aqueous phase chain extension, yielding an aqueous polyurethane-organic silicone composite emulsion.
[0053] Step 2: Add 6.0 g of trimethylolpropane triglycidyl ether (TMP-TGE) and 0.1 g of dibutyltin dilaurate to a mixed solvent consisting of 25 mL of N,N-dimethylformamide (DMF) and 75 mL of anhydrous ethanol (DMF:ethanol volume ratio = 1:3). Stir at room temperature for 25 min until completely dissolved to obtain a swelling crosslinking solution. Immerse 5.0 g of polyether-type spandex fiber (40D) in the swelling crosslinking solution and treat it at 48℃ for 45 min, gently turning the fiber every 10 min during the treatment. Remove the fiber and dry it in three stages: first pre-dry at 60℃ for 12 min, then dry at 102℃ for 18 min, and finally heat-cur at 130℃ for 30 min to obtain crosslinked modified spandex fiber.
[0054] Step 3: Cross-linked modified spandex fiber is used as the elastic yarn and woven with nylon filament (70D / 24F) on a warp knitting machine according to the warp knitting structure. The feed rate is controlled so that the mass ratio of cross-linked modified spandex fiber to nylon filament in the finished fabric is approximately 2:9. After weaving, the fabric is laid flat and relaxed for 12 hours under no tension to obtain the elastic fabric greige.
[0055] Step 4: Dissolve 0.5g of sodium carboxymethyl cellulose (CMC-Na, degree of substitution 0.9, viscosity-average molecular weight 100,000) in 30g of deionized water, stir at room temperature for 40min until completely dissolved, then add 1.4g of citric acid and stir for 5min until dissolved to obtain a CMC-Na / citric acid aqueous solution. Separately, take 100.0g of waterborne polyurethane-silicone composite emulsion, add 2.4g of butanone oxime-terminated hexamethylene diisocyanate trimer (effective -NCO content approximately 12wt%), and stir for 10min to mix thoroughly. Slowly pour the CMC-Na / citric acid aqueous solution into the emulsion mixture and stir thoroughly. Slowly add 5wt% sodium bicarbonate aqueous solution to adjust the pH to 4.5. Add deionized water to adjust the total amount of finishing solution to 150g, and stir thoroughly to obtain an elastic finishing solution.
[0056] Step 5: Impregnate the elastic fabric with an elastic finishing liquid using a two-dip, two-ply process, with a roll-off rate of 78%. Pre-dry at 85℃ for 4 minutes, then bake at 160℃ for 2 minutes. Remove and allow to cool naturally to room temperature to obtain a high-resilience spandex fiber fabric.
[0057] Example 5
[0058] A method for preparing a high-resilience spandex fiber fabric includes the following steps:
[0059] Step 1: In a 500 mL four-necked flask equipped with a mechanical stirrer, thermometer, condenser, and nitrogen delivery tube, add 100.0 g of polytetrahydrofuran diol (PTMG, molecular weight 1000, hydroxyl value 112 mg KOH / g). Dehydrate at 110 °C and a vacuum of -0.09 MPa for 2 h, then cool to 80 °C for later use. In another container, add 5.0 g of dimethylolpropionic acid (DMPA) to 7.0 g of N-methylpyrrolidone (NMP) and stir at 60 °C until completely dissolved. Add the DMPA / NMP solution to the four-necked flask, then add 40.0 g of isophorone diisocyanate (IPDI) and 0.05 g of dibutyltin dilaurate (DBTDL) sequentially. React at 80 °C for 2.5 h under nitrogen protection. Stop the reaction when the -NCO content drops to approximately 2.65 wt% by di-n-butylamine titration. The temperature was lowered to 50℃, and 5.0 g of triethylamine (TEA) was added for neutralization for 15 min. Then, 11.1 g of amino silicone oil (ammonia value 0.45 mmol / g) was slowly added dropwise over a period of at least 15 min, and the chain extension reaction was carried out at 50℃ for 30 min. The stirring speed was increased to 2500 rpm, and 414 g of deionized water was slowly added for emulsification and dispersion. After emulsification, the stirring speed was reduced to 800 rpm, and 2.85 g of ethylenediamine was slowly added dropwise (completed over approximately 5 min). The stirring was continued for 20 min to complete the aqueous phase chain extension, yielding an aqueous polyurethane-organic silicone composite emulsion.
[0060] Step 2: Add 4.0 g of trimethylolpropane triglycidyl ether (TMP-TGE) and 0.1 g of dibutyltin dilaurate to a mixed solvent consisting of 25 mL of N,N-dimethylformamide (DMF) and 75 mL of anhydrous ethanol (DMF:ethanol volume ratio = 1:3). Stir at room temperature for 25 min until completely dissolved to obtain a swelling crosslinking solution. Immerse 5.0 g of polyether-type spandex fiber (40D) in the swelling crosslinking solution and treat it at 48℃ for 45 min, gently turning the fiber every 10 min during the treatment. Remove the fiber and dry it in three stages: first pre-dry at 60℃ for 12 min, then dry at 102℃ for 18 min, and finally heat-cur at 130℃ for 30 min to obtain crosslinked modified spandex fiber.
[0061] Step 3: Cross-linked modified spandex fiber is used as the elastic yarn and woven with nylon filament (70D / 24F) on a warp knitting machine according to the warp knitting structure. The feeding is controlled so that the mass ratio of cross-linked modified spandex fiber to nylon filament in the finished fabric is approximately 2:7. After weaving, the fabric is laid flat and relaxed for 12 hours under no tension to obtain the elastic fabric greige.
[0062] Step 4: Dissolve 0.5g of sodium carboxymethyl cellulose (CMC-Na, degree of substitution 0.9, viscosity-average molecular weight 100,000) in 30g of deionized water, stir at room temperature for 40min until completely dissolved, then add 1.0g of citric acid and stir for 5min until dissolved to obtain a CMC-Na / citric acid aqueous solution. Separately, take 100.0g of waterborne polyurethane-silicone composite emulsion, add 2.4g of butanone oxime-terminated hexamethylene diisocyanate trimer (effective -NCO content approximately 12wt%), and stir for 10min to mix thoroughly. Slowly pour the CMC-Na / citric acid aqueous solution into the emulsion mixture and stir thoroughly. Slowly add 5wt% sodium bicarbonate aqueous solution to adjust the pH to 4.5. Add deionized water to adjust the total amount of finishing solution to 150g, and stir thoroughly to obtain an elastic finishing solution.
[0063] Step 5: Impregnate the elastic fabric with an elastic finishing liquid using a two-dip, two-ply process, with a roll-off rate of 78%. Pre-dry at 85℃ for 4 minutes, then bake at 160℃ for 2 minutes. Remove and allow to cool naturally to room temperature to obtain a high-resilience spandex fiber fabric.
[0064] Comparative Example 1: The difference from Example 1 is that step 2 is omitted, and unmodified polyether-type spandex fiber (40D) is used directly to replace the cross-linked modified spandex fiber and woven into fabric with nylon filament in the same proportion. The finishing solution formulation, padding process and baking conditions in subsequent steps 3 to 5 are exactly the same as in Example 1.
[0065] Comparative Example 2: The only difference from Example 1 is that steps 1 to 3 are completed normally, but steps 4 and 5 are omitted, that is, the preparation of the elastic finishing liquid and the padding and baking are not carried out. After being woven into fabric, it becomes the final product. All other conditions are exactly the same as in Example 1.
[0066] Comparative Example 3: The only difference from Example 1 is that sodium carboxymethyl cellulose and citric acid are not added when preparing the elastic finishing solution in step 4.
[0067] Comparative Example 4: The only difference from Example 1 is that in step 4, when preparing the elastic finishing solution, citric acid was added according to the amount used in Example 1, but sodium carboxymethyl cellulose was not added.
[0068] Comparative Example 5: The only difference from Example 1 is that when preparing the elastic finishing solution in step 4, sodium carboxymethyl cellulose was added according to the amount used in Example 1, but citric acid was not added.
[0069] Performance testing:
[0070] 1. Elastic recovery rate test: Ten strip samples with dimensions of 250mm × 50mm were cut along the warp direction from each group of fabric samples and conditioned for 24 hours in a constant temperature and humidity environment (temperature 20±2℃, relative humidity 65±4%). The samples were clamped between the upper and lower clamps of a universal testing machine with a clamping distance of 100mm. The samples were stretched to 300% of their original length at a tensile rate of 500mm / min (i.e., the clamping distance was stretched from 100mm to 300mm). After maintaining this elongation for 1 minute, the samples were retracted to the initial clamping distance at the same rate. After resting for 1 hour, the length of the samples was measured again. The elastic recovery rate at a constant elongation was calculated using the formula: elastic recovery rate (%) = [(stretch length - residual elongation) / (stretch length - initial length)] × 100%. The arithmetic mean of the 10 samples was taken as the test result. The test results are shown in Table 1.
[0071] 2. Stress relaxation rate test: Five 250mm × 50mm strip samples were cut from each group of fabric samples along the warp direction and conditioned for 24 hours under the above constant temperature and humidity conditions. The samples were clamped on a universal testing machine with a clamping distance of 100mm and stretched at a rate of 300mm / min to 100% constant elongation (i.e., stretching from a clamping distance of 100mm to 200mm). This elongation displacement was kept constant, and the instantaneous tensile stress F0 was recorded. The stress change was continuously recorded while maintaining the constant elongation. The stress value F was read after 30 minutes. 30 According to the formula, stress relaxation rate (%) = [(F0 - F 30 The arithmetic mean of the five samples was calculated as 100% (F0) / F0, and the result was taken as the arithmetic mean of the five samples. The test results are shown in Table 1.
[0072] 3. Washing Resistance and Elasticity Retention Test: Fabric samples (300mm × 300mm) were placed in a standard washing machine at 40℃. Standard detergent (ECE standard detergent, 4g / L) was added, and the samples were washed for 40 minutes, then spun dry and laid flat to air dry at room temperature. After 10, 30, and 50 washes respectively, strips were cut from the washed fabric and the 300% elastic recovery rate was measured using the aforementioned elasticity recovery rate test method. The elasticity retention rate (%) = (300% elastic recovery rate after washing / 300% elastic recovery rate before washing) × 100% characterizes the wash resistance durability of the fabric's elasticity. The arithmetic mean of 5 samples was taken as the test result. The test results are shown in Table 1.
[0073] 4. Tensile Strength and Elongation at Break Test: Five 300mm × 50mm strips were cut from each group of fabric samples along the warp direction and conditioned in a constant temperature and humidity environment for 24 hours. The samples were clamped on a universal testing machine with a clamping distance of 200mm and stretched at a constant speed of 100mm / min until the sample broke. The maximum tensile force at break was recorded as the tensile strength (N), and the ratio of the elongation at break to the initial clamping distance was recorded as the elongation at break (%). The arithmetic mean of the five samples was taken as the test result. The test results are shown in Table 1.
[0074] 5. Elastic Recovery Rate Test After Repeated Tensile Fatigue: To evaluate the durability of the fabric's elastic properties during long-term repeated use, a cyclic tensile fatigue test was conducted on the fabric. Five 250mm × 50mm strips were cut along the warp direction from each group of fabric samples, clamped at a distance of 100mm, stretched to 100% of their set elongation at a rate of 300mm / min, and then retracted to their initial position at the same rate. This stretching-retraction cycle was repeated 1000 times. After 1000 cycles, the samples were removed from the testing machine and allowed to recover flat for 24 hours under no-tension conditions. Then, the 300% elastic recovery rate was measured according to the aforementioned elastic recovery rate test method. Compared with the elastic recovery rate before fatigue, the elasticity retention rate after fatigue (%) was calculated as follows: (300% elastic recovery rate after fatigue / 300% elastic recovery rate before fatigue) × 100%. The arithmetic mean of the five samples was taken as the measurement result. The test results are shown in Table 1.
[0075] Table 1:
[0076] Sample 300% recovery / % stress relaxation / % breaking strength / N elongation at break / % 10 wash retention / % 30 wash retention / % 50 wash retention / % 1000 fatigue recovery / % 1000 fatigue retention / % Example 1 97.6 15.8 289.3 308.6 99.1 96.8 93.7 96.1 98.5 Example 2 96.8 17.0 276.5 318.2 98.9 96.2 92.8 95.3 98.4 Example 3 97.2 16.3 283.8 312.5 99.0 96.5 93.2 95.8 98.6 Example 4 97.9 15.2 296.1 295.4 99.2 97.1 94.3 96.5 98.6 Example 5 96.3 17.5 271.2 326.7 98.6 95.7 92.1 94.7 98.3 Comparative Example 1 93.5 26.7 253.6 341.5 96.2 89.5 83.1 90.8 97.1 Comparative Example 2 95.2 22.4 270.8 286.3 99.5 98.9 98.2 93.6 98.3 Comparative Example 3 95.8 20.9 275.2 302.7 97.5 91.2 86.4 93.2 97.4 Comparative Example 4 96.4 18.7 281.6 306.8 98.3 94.1 90.2 94.5 98.0 Comparative Example 5 96.2 19.3 278.4 308.1 97.8 92.5 87.6 93.8 97.5
[0077] As shown in Table 1, the 300% elastic recovery rate of the fabrics obtained in Examples 1 to 5 is between 96.3% and 97.9%, and the stress relaxation rate is between 15.2% and 17.5%. The overall performance level is significantly better than all comparative examples, indicating that the technical solution of the present invention can achieve good performance within the range of the claims parameters.
[0078] Comparative Example 1 (coating only, without fiber crosslinking modification) had the lowest recovery rate (93.5%) and the highest stress relaxation rate (26.7%), indicating that the uncrosslinked spandex fibers experienced severe irreversible slippage of molecular chains under large deformations, and a single coating treatment could not fundamentally prevent this slippage. Comparative Example 2 (fiber crosslinking modification only, without coating) had a recovery rate of 95.2%, better than Comparative Example 1 but significantly lower than all examples, indicating that inter-yarn friction and weave structure relaxation at the fabric level still consume some elastic recovery energy, requiring the assistance of a coating. Comparative Example 3 (without citric acid and CMC-Na) had a recovery rate of 95.8%, only slightly higher than Comparative Example 2, but far lower than Example 1 (97.6%), demonstrating that in the absence of the interfacial transition layer constructed with citric acid and CMC-Na, the coating and modified fibers did not bond well and could not effectively synergize. The performance of Comparative Example 4 (citric acid only) and Comparative Example 5 (CMC-Na only) is between that of Comparative Example 3 and the Example, proving that both covalent bridging and physical entanglement are indispensable interfacial bonding mechanisms.
[0079] After 50 washes, the elastic recovery rates of Examples 1-5 were 93.7%, 92.8%, 93.2%, 94.3%, and 92.1%, respectively, all remaining above 92%, demonstrating excellent wash resistance. Example 4 showed the highest retention rate (94.3%), directly related to its high crosslinking density and high citric acid interfacial bridging density. Comparative Example 1 showed a retention rate of only 83.1% after 50 washes, with significant coating detachment during washing. This is because the unmodified fiber surface lacks residual epoxy groups, preventing covalent anchoring of citric acid; the coating relies solely on physical adsorption. Comparative Example 3 showed a retention rate of 86.4%. Although the fiber was crosslinked and modified, the coating-fiber interface lacked compatibilizing components, leading to gradual coating peeling during washing. Comparative Example 4 (citric acid only) showed a significantly higher retention rate of 90.2% than Comparative Example 5 (CMC-Na only) at 87.6%, indicating that covalent ester bridging has better wash resistance (covalent bonds are not eroded by water), while simple hydrogen bonds and physical entanglements are easily disrupted by water molecules during washing. Notably, Comparative Example 2 (fiber crosslinking modification only, no coating) achieved a high wash retention rate of 98.2%, because there was no coating peeling issue, and the chemical crosslinking network within the fiber itself possessed excellent wash resistance stability. However, its absolute elastic properties (initial recovery rate of 95.2%) were lower than those of the other examples.
[0080] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a high-resilience spandex fiber fabric, characterized in that, Includes the following steps: 1) A prepolymer was synthesized by reacting polytetrahydrofurandiol, dimethylolpropionic acid, isophorone diisocyanate and dibutyltin dilaurate; triethylamine was added for neutralization, and amino silicone oil was added for chain extension reaction; emulsification and dispersion were carried out, and ethylenediamine was added for chain extension to obtain an aqueous polyurethane-silicone composite emulsion. 2) Polyether-type spandex fibers were swollen and impregnated using trimethylolpropane triglycidyl ether and dibutyltin dilaurate. After removal, they were dried and heat-cured in sequence to obtain cross-linked modified spandex fibers. 3) Cross-linked modified spandex fiber is used as elastic yarn and nylon filament is woven together, and after relaxation, elastic fabric greige is obtained. 4) After mixing sodium carboxymethyl cellulose with citric acid, add it to the mixture composed of the aqueous polyurethane-silicone composite emulsion and methyl ethyl ketone oxime-terminated hexamethylene diisocyanate trimer to obtain an elastic finishing liquid; 5) The elastic fabric is impregnated in the elastic finishing liquid, and then pre-dried and cured to obtain a high-resilience spandex fiber fabric.
2. The method for preparing a high-resilience spandex fiber fabric according to claim 1, characterized in that, In step 1), the mass ratio of polytetrahydrofuran diol to dimethylolpropionic acid is 100:(5-8).
3. The method for preparing a high-resilience spandex fiber fabric according to claim 1, characterized in that, In step 1), the mass ratio of polytetrahydrofuran diol to isophorone diisocyanate is 100:(40-50).
4. The method for preparing a high-resilience spandex fiber fabric according to claim 1, characterized in that, In step 2), the mass ratio of polyether-type spandex fiber to trimethylolpropane triglycidyl ether is 5:(4-6).
5. The method for preparing a high-resilience spandex fiber fabric according to claim 1, characterized in that, In step 3), the mass ratio of cross-linked modified spandex fiber as elastic yarn to nylon filament is 2:(7-9).
6. The method for preparing a high-resilience spandex fiber fabric according to claim 1, characterized in that, In step 4), the mass ratio of sodium carboxymethyl cellulose to citric acid is 5:(10-14).
7. The method for preparing a high-resilience spandex fiber fabric according to claim 1, characterized in that, In step 4), the mass ratio of the aqueous polyurethane-silicone composite emulsion to the butanone oxime-terminated hexamethylene diisocyanate trimer is 100:(2-5).
8. A high-resilience spandex fiber fabric, characterized in that, Prepared by the method described in any one of the preceding claims.