Three-dimensional dynamic netted fatigue-resistant split pressure spandex fiber and preparation method thereof
By using a three-dimensional dynamic network structure design and dynamic cross-linking technology, the problems of easy deformation and oxidation of traditional spandex fibers have been solved, resulting in spandex fibers with better durability and stability, suitable for applications such as bras.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BIYUE (BEIJING) TECH CO LTD
- Filing Date
- 2025-09-23
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional spandex fibers are prone to permanent deformation, stress concentration, and oxidative degradation during long-term use, resulting in decreased elasticity and color changes, especially in bra applications where they are prone to loosening and yellowing.
By employing a three-dimensional dynamic network structure design and dynamic cross-linking technology, a polyurethane urea solution is formed through polyol prepolymerization, isocyanate polymerization, chain extender addition, and auxiliary agent treatment. After curing, degassing, and spinning, a three-dimensional dynamic network fatigue-resistant partial pressure spandex fiber is prepared.
It significantly improves the durability, stability, and functionality of spandex fibers, resulting in a more stable skeleton, better tensile recovery, less tendency to loosen and yellow, and maintains high elasticity.
Smart Images
Figure CN121023686B_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of spandex fiber preparation technology, specifically relating to a three-dimensional dynamic mesh fatigue-resistant pressure-distributing spandex fiber and its preparation method. Background Technology
[0002] Traditional spandex fibers are composed of linear block copolymers with a chain structure. After prolonged stretching, the soft segments of the molecular chains are prone to chain slippage, while the microcrystalline regions of the hard segments are damaged, leading to increased permanent deformation and fabric loosening. Simultaneously, under long-term stress, stress concentration occurs within the fiber, weakening the bond between the hard and soft segments and reducing elasticity. This is particularly noticeable when spandex fibers are used in bras; after repeated stretching, the underband area is prone to loosening. Furthermore, when traditional spandex is exposed to ultraviolet light for extended periods, the soft and hard segments of the spandex molecular chains undergo oxidative degradation, generating color-producing substances such as aldehydes and ketones, causing the fiber to gradually yellow and exhibiting poor stability. Summary of the Invention
[0003] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a three-dimensional dynamic mesh fatigue-resistant pressure-splitting spandex fiber and its preparation method.
[0004] One aspect of this disclosure provides a method for preparing three-dimensional dynamic mesh fatigue-resistant spandex fibers, the preparation method comprising:
[0005] A polyol is prepolymerized to form a prepolymer, and an isocyanate is added to the prepolymer to produce a polymerization solution.
[0006] A chain extender is added to the polymerization solution, and an addition reaction is carried out to form a polyurethane urea solution;
[0007] Adding an auxiliary agent to the polyurethane urea solution and stirring it together forms a spandex spinning solution.
[0008] The spandex spinning solution is subjected to aging treatment, defoaming treatment and spinning treatment to obtain three-dimensional dynamic network fatigue-resistant pressure-splitting spandex fiber.
[0009] Optionally, the prepolymerization of polyols to form prepolymers includes:
[0010] The polyol is preheated at 55-65℃ for 3-7 minutes, then cooled to 35-45℃ and reacted for 60-70 minutes.
[0011] Optionally, the temperature of the MDI polymerization reaction in the prepolymer is 32-36℃ and the time is 550-65min.
[0012] Optionally, the chain extender includes a primary chain extender and a co-chain extender; wherein,
[0013] The main chain extender is ethylenediamine;
[0014] The co-chain extender is propylenediamine or pentanediamine.
[0015] Optionally, the main chain extender accounts for 80-100% of the total molar amount of the chain extender.
[0016] Optionally, the additives include matting agents, soothing agents, anti-yellowing agents, and antioxidants.
[0017] Optionally, the matting agent is titanium dioxide;
[0018] The relieving agent is magnesium stearate;
[0019] The anti-yellowing agent is a polymer of bis(4-isocyanocyclohexyl)methane and N-tert-butyl-N,N-diethanolamine or an environmentally friendly phosphite.
[0020] The antioxidant is bis[β(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] triethylene glycol ester or 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione.
[0021] Optionally, the content of the matting agent is 0.2-2% of the content of the polymerization solution;
[0022] The content of the decongestant is 0.1-0.5% of the content of the polymerization solution;
[0023] The content of the anti-yellowing agent is 0.2-0.5% of the content of the polymerization solution;
[0024] The antioxidant content is 0.6-1% of the polymerization solution content.
[0025] Optionally, the aging process is carried out at a temperature of 30-36°C for 27-36 hours.
[0026] In another aspect of this disclosure, a three-dimensional dynamic mesh fatigue-resistant and pressure-splitting spandex fiber is provided, which is prepared by the preparation method described above.
[0027] This disclosure discloses a three-dimensional dynamic network fatigue-resistant and pressure-resistant spandex fiber and its preparation method. The preparation method of the three-dimensional dynamic network fatigue-resistant and pressure-resistant spandex fiber includes: prepolymerizing a polyol to form a prepolymer; adding an isocyanate to the prepolymer for polymerization to generate a polymerization solution; adding a chain extender to the polymerization solution and reacting it to generate a polyurethane urea solution; adding an auxiliary agent to the polyurethane urea solution and stirring to form a spandex spinning solution; and subjecting the spandex spinning solution to aging, defoaming, and spinning treatments to obtain the three-dimensional dynamic network fatigue-resistant and pressure-resistant spandex fiber. This disclosure upgrades spandex from a single chain structure to a network structure through the combined effect of the above steps. Through innovative three-dimensional network structure design and dynamic cross-linking technology, it significantly improves its durability, stability, and functionality while maintaining the high elasticity of traditional spandex. Furthermore, the prepared network spandex has a more stable skeleton, superior physicochemical properties, better tensile recovery, is less prone to loosening, and is less prone to yellowing. Attached Figure Description
[0028] Figure 1 This is a flowchart illustrating the preparation method of a three-dimensional dynamic mesh fatigue-resistant pressure-splitting spandex fiber according to a specific embodiment of this disclosure.
[0029] Figure 2 This is a schematic diagram of the structure of a three-dimensional dynamic mesh fatigue-resistant pressure-distributing spandex fiber according to a specific embodiment of this disclosure. Detailed Implementation
[0030] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.
[0031] like Figure 1 As shown, one aspect of this disclosure provides a method S100 for preparing a three-dimensional dynamic mesh fatigue-resistant spandex fiber, specifically including the following steps S110 to S140:
[0032] S110. Polymerize the polyol to form a prepolymer, and add isocyanate to the prepolymer to generate a polymerization solution.
[0033] It should be understood that the raw materials for the production of spandex include soft segment substrate (polyol) and hard segment raw material (isocyanate) components, which are prepolymerized to form a prepolymer.
[0034] In step S110, the polyol is first preheated at 55-65°C for 3-7 minutes under solvent-free conditions, then cooled to 35-45°C and reacted for 60-70 minutes to form a prepolymer. Then, isocyanate is added to the prepolymer, and a prepolymerization reaction is carried out at 32-36°C for 550-65 minutes to form a polymerization solution.
[0035] It should be noted that the reaction temperature of the prepolymer should not exceed 80℃, that is, the maximum reaction temperature should be controlled at 80℃. In this way, under solvent-free conditions, the terminal hydroxyl groups (-OH) of the polyol undergo a preliminary addition reaction with the trace amount of residual isocyanate (or the small amount of MDI added beforehand) in the system to generate short-chain oligomers. The reaction is then terminated by rapid cooling to avoid local overheating and uneven molecular weight distribution caused by the exothermic reaction in the solvent-free system.
[0036] In step S110, the polyol can be RA-1, and the isocyanate can be MDI. The two are reacted to generate a prepolymer with an active group (-NCO) at the end, namely a urethane bond (-NHCOO-).
[0037] It should be noted that the polyol in RA-1 is a mixture of polyether diol with a molecular weight of 1800-2000 and glycerol, trimethylolethane, or trimethylolpropane, wherein the molar percentage of glycerol, trimethylolethane, or trimethylolpropane in the mixture is 1%-3%, and the molar ratio of MDI to polyol must be in the range of 1.65-2.05.
[0038] This embodiment divides the polymerization process into two steps, including bulk prepolymerization and solution prepolymerization, which can precisely control the ratio of soft segments and hard segments to generate a soluble active prepolymer, laying the foundation for chain extension and spinning.
[0039] S120. A chain extender is added to the polymerization solution, and an addition reaction is carried out to generate a polyurethane urea solution.
[0040] Specifically, a chain extender is added to the polymerization solution formed in step S110 to give the spandex better physical, chemical and tensile recovery properties.
[0041] In some preferred embodiments, the chain extender includes a primary chain extender and a co-chain extender; wherein the primary chain extender is ethylenediamine (EDA); and the co-chain extender is propylenediamine (e.g., 1,2-propylenediamine, PDA) or pentanediamine (e.g., 2-methyl-1,5-pentanediamine, PTDA).
[0042] As a further preferred embodiment, the primary chain extender accounts for 80-100% of the total molar amount of the chain extender. That is, in some embodiments, when the content of the primary chain extender is 100%, the chain extender may consist of the primary chain extender. In other embodiments, when the content of the primary chain extender is less than 100% but greater than 80%, the chain extender consists of the primary chain extender and the co-chain extender.
[0043] In some preferred embodiments, the chain extender includes a primary chain extender and a co-chain extender. Through the synergistic use of the primary chain extender and the co-chain extender, which contain 4 -NH2 groups, it can react with the -NCO of 2-3 prepolymer molecules at the same time to form a node-type cross-linked structure and construct a three-dimensional network. This can balance the "strength-elasticity-softness" of spandex while improving yellowing resistance and spinning processability.
[0044] S130. Add additives to the polyurethane urea solution and stir to form a spandex spinning solution.
[0045] In step S130, the additives include matting agents, soothing agents, anti-yellowing agents, and antioxidants. These additives are added to the polyurethane urea solution, and the mixture is stirred at 25-35 rpm for 85-95 minutes.
[0046] In some preferred embodiments, the content of the matting agent is 0.2-2% of the content of the polymerization solution, and the matting agent is preferably titanium dioxide. This component can adjust the gloss of the spandex according to customer needs. If no matting agent is added, it is bright spandex; if the matting agent is added at a ratio of 0.2%-1.5%, it is semi-glossy spandex; and if the matting agent is added at a ratio of 1.6%-2%, it is natural white spandex.
[0047] In some other preferred embodiments, the content of the unwinding agent is 0.1-0.5% of the content of the polymerization solution, and magnesium stearate is preferred as the unwinding agent. Its function is to reduce the friction coefficient on the surface of the spandex polymer, increase the isolation between monofilaments, and have a lubricating effect. Generally, the addition ratio of coarse denier filaments is preferably 0.1%-0.25%, and the addition ratio of fine denier filaments is generally preferably 0.26%-0.5%. If the addition ratio is too high, it will cause cobweb-like filaments to affect the formation of the yarn roll. If the addition ratio is too low when spinning porous yarn, it will cause the yarn to be adjusted by the spinning false twister and the monofilaments of the yarn roll to stick together, making unwinding difficult.
[0048] In some other preferred embodiments, the content of the anti-yellowing agent is 0.2-0.5% of the content of the polymerization solution, and the main component of the anti-yellowing agent is a polymer of bis(4-isocyanocyclohexyl)methane and N-tert-butyl-N,N-diethanolamine or an environmentally friendly phosphite, which serves to prevent heat yellowing and light yellowing.
[0049] In some other preferred embodiments, the antioxidant content is 0.6-1% of the polymerization solution content, and the antioxidant is bis[β(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] triethylene glycol ester or 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, which mainly prevents high-temperature oxidation of the polymer and prevents high-temperature oxidation of the spandex filaments during spinning and subsequent fabric processing.
[0050] S140. The spandex spinning solution is subjected to aging treatment, defoaming treatment and spinning treatment to obtain three-dimensional dynamic network fatigue-resistant pressure-distributing spandex fiber.
[0051] In step S140, the curing temperature is 30-36℃ and the time is 27-36h. The crosslinking points are rearranged through the thermal motion of molecular chains to ensure the balance of the strength of the network elastic domains.
[0052] In step S140, the deaerated solution is pumped to the spinneret via a metering gear pump. The number of orifices is adjusted according to the fineness, and the solution is extruded to form a fine stream. The fine stream enters the dry spinning duct and comes into contact with the gradient hot air provided by the SCM fan circulation system, where the solvent evaporates and solidifies. The hot air inlet parameters are: upper inlet temperature 220-260℃, air volume 8.5-22m³ / h. 3 / min; lower outlet temperature 180-200℃, air volume 3.6-8.8m³ / min. 3 / min, vertical airflow ratio (3.5-4):(6-6.5), DMAc gas volume content in the high-temperature mixed gas ranges from 0.37% to 1.05%; hot air outlet temperature is 220-240℃, airflow is 5.4-13.2m³ / min. 3 The volume content of DMAc gas in the high-temperature mixed gas ranges from 0.37% to 1.05% per minute.
[0053] Furthermore, the spinning process should also include a winding process to collect and initially draw the nascent fibers. The nascent fibers exiting from the bottom of the duct are drawn by the guide rollers and pre-drawn at a low ratio of 1000-1500 m / min, which slightly orients the soft segments and makes the network structure more compact. The pre-drawn fibers are then wound onto a paper tube by a winding machine to form a bobbin.
[0054] Furthermore, the preparation process also includes balancing treatment, in which the wound filament bobbin is sent into a balancing chamber and left to stand at a certain temperature. Through the thermal motion of molecular chains, the hard segment microcrystalline regions are further regularized, the stress of chemical cross-linking nodes and soft segment chains is relaxed, and the network structure reaches thermodynamic equilibrium.
[0055] This embodiment, through the combined action of the above-described processes, upgrades spandex from a single chain structure to a network structure via chain extension polymerization. Through innovative three-dimensional network structure design and dynamic cross-linking technology, a three-dimensional dynamic network fatigue-resistant and pressure-resistant spandex fiber is formed. While maintaining the high elasticity of traditional spandex, its durability, stability, and functionality are significantly improved. The resulting network spandex skeleton is more stable, has superior physicochemical properties, better tensile recovery, is less prone to loosening, and is less prone to yellowing.
[0056] Another aspect of this disclosure proposes a three-dimensional dynamic mesh fatigue-resistant and pressure-splitting spandex fiber, which is prepared by the preparation method described above. For details, please refer to the above description and will not be repeated here.
[0057] like Figure 2 As shown, the structure of the three-dimensional dynamic network fatigue-resistant spandex fiber exhibits front-end copolymer characteristics, consisting of alternating hard and soft segments. The soft segments are composed of aliphatic polyether or aliphatic polyester segments with long and flexible molecular chains, dispersed between the hard segments in a random coiled state. Under stress, they can be stretched and straightened, giving spandex high elasticity and elongation. The hard segments are rigid urea segments generated by the reaction of diisocyanate and chain extender. The molecules are tightly arranged through hydrogen bonds (NH…O=C), forming physical crosslinking points, which endow spandex with strength, heat resistance, and structural stability, preventing deformation. The soft and hard segments are alternately connected by covalent bonds to form a block copolymer, which combines elasticity and strength.
[0058] The three-dimensional dynamic mesh fatigue-resistant pressure-splitting spandex fiber of this embodiment refers to the mesh spandex with a special structure formed in this disclosure. This mesh spandex has connection points in both the transverse and longitudinal directions, increasing the bonding force between hard and soft segments, and possessing elasticity and strength. It also has good stability, is not easily loosened, and has improved resilience.
[0059] The preparation process of three-dimensional dynamic mesh fatigue-resistant pressure-splitting spandex fiber will be further explained below with reference to specific embodiments:
[0060] Example 1
[0061] The preparation method of the mesh spandex in this example includes the following steps:
[0062] S1, Prepolymerization process:
[0063] RA-1 bulk prepolymerization process: RA-1 is preheated at a preheating temperature of 60℃ for 5 minutes, then cooled for 34 minutes, and then reacted for 65 minutes after cooling, with a maximum reaction temperature of 80℃ to form a prepolymer.
[0064] RA-1 solution prepolymerization process: MDI is added to the prepolymer, and the temperature of the MDI is maintained at 16°C to allow the two to react. The reaction time is 600 min at 34°C to form a polymerization solution.
[0065] S2, Chain Extension:
[0066] Adding chain extenders to the polymerization solution gives spandex superior physicochemical and tensile recovery properties. The chain extenders are ethylenediamine (EDA) and propylenediamine (1,2-propanediamine, PDA), with the main chain extender accounting for 90% of the total molar amount of the chain extender.
[0067] S3. Adding additives:
[0068] Add titanium dioxide (0.5% of the polymerization solution content), magnesium stearate (0.3% of the polymerization solution content), LDZ-9 (0.2% of the polymerization solution content), and OA245 (0.7% of the polymerization solution content) to the stock solution, and stir at 30 rpm for 90 min.
[0069] S4. Curing of the original solution:
[0070] Add the stock solution from step S3 to the stock solution storage tank and mature it at 33°C for 30 hours.
[0071] S5, Defoaming:
[0072] The matured stock solution is first filtered through two stages of metal filters at a pressure of 0.2 MPa and a flow rate of 70 L / h to ensure the clarity of the stock solution.
[0073] S6, spinning:
[0074] After degassing, the raw liquid is precisely metered by a gear pump, and the flow rate is adjusted according to the target fineness. The raw liquid enters the spinning assembly through the distribution pipe, and after secondary filtration by the filter screen, it reaches the spinneret. The raw liquid extruded from the spinneret holes forms a continuous liquid flow under the action of gravity and traction, and enters the channel to contact with high-temperature hot air.
[0075] The tunnel achieves a temperature gradient distribution through upper and lower inlet hot air flows, and the gradient hot air evaporates the solvent.
[0076] Upper hot air inlet: temperature 240℃, air volume 11m³ 3 / min;
[0077] Lower hot air inlet: temperature 190℃, air volume 5.5m³ / h 3 / min;
[0078] Air volume ratio: 3.5:6 for upper and lower inlet air volume.
[0079] Further, at high temperatures, the residual terminal-NCO groups in the original solution are further reacted with the unreacted chain extender amino groups. During the solvent evaporation process, the hard segments aggregate through hydrogen bonds to form microcrystalline physical cross-linking points, which, together with the chemical cross-linking nodes, constitute a three-dimensional network framework.
[0080] Furthermore, the cured fibers are pulled away from the tunnel by the guide roller group at the bottom of the tunnel, resulting in nascent mesh spandex fibers.
[0081] S7, winding:
[0082] The nascent fibers emerging from the spinning tunnel first pass through the guide roller assembly. The rotation of the rollers provides traction, and the guide wheels guide the fibers into the winding mechanism for winding and shaping.
[0083] S8, Balance:
[0084] The wound yarn bobbins are placed horizontally or vertically on a balancing frame and stacked to obtain three-dimensional dynamic mesh fatigue-resistant pressure-splitting spandex fibers.
[0085] Based on the preparation process of Example 1, experiments were conducted on different batches of the obtained mesh spandex fibers. The decomposition temperature range of the different batches was 250℃-265℃, the tensile breaking strength range was 0.86cN / dtex-1.6cN / dtex, the 300% springback recovery rate range was 90%-96%, and the 200% strain recovery tension at the fifth springback was 0.9-1.6cN.
[0086] Comparative Example 1
[0087] This example uses 40D conventional spandex, which has a decomposition temperature of 220-230℃, a tensile breaking strength of 0.75-1.4cN / dtex, a 300% springback recovery rate of 80-95%, and a 200% strain recovery tension (TM2,cN) of 0.8-1.4cN at the fifth springback.
[0088] Based on the results of Example 1 and Comparative Example 1, it can be seen that the mesh spandex prepared in this disclosure has good stability, strength and resilience. Compared with conventional spandex, its thermal decomposition temperature, strength and recovery tension are about 15% higher.
[0089] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.
Claims
1. A method for preparing a three-dimensional dynamic mesh fatigue-resistant spandex fiber, characterized in that, The preparation method includes: The polyol is preheated at 55-65℃ for 3-7 minutes, then cooled to 35-45℃ and reacted for 60-70 minutes to form a prepolymer. The polyol used has a molecular weight of 1800. A mixture of 2000 polyether diols with glycerol, trimethylolethane, or trimethylolpropane; wherein the molar percentage of glycerol, trimethylolethane, or trimethylolpropane in the mixture is 1%. 3%; An isocyanate is added to the prepolymer for polymerization at a temperature of 32-36°C, resulting in the formation of a product with terminal active groups. Prepolymerization solution of NCO; A chain extender is added to the polymerization solution, and an addition reaction is carried out to form a polyurethane urea solution. The chain extender includes a main chain extender and a co-chain extender. The main chain extender is ethylenediamine, and the co-chain extender is propylenediamine or pentanediamine. The four -NH2 groups in the chain extender react with the -NCO groups of 2-3 prepolymer molecules to form a node-type crosslinked structure, thereby constructing a three-dimensional network. Adding an auxiliary agent to the polyurethane urea solution and stirring it together forms a spandex spinning solution. The spandex spinning solution is subjected to aging treatment, defoaming treatment and spinning treatment to obtain three-dimensional dynamic network fatigue-resistant pressure-distributing spandex fiber; The three-dimensional dynamic mesh fatigue-resistant spandex fiber is composed of alternating hard and soft segments. The soft segments are made of aliphatic polyethers, while the hard segments are rigid urea segments generated by the reaction of diisocyanate and chain extender. The molecules are tightly arranged through hydrogen bonds to form physical cross-linking points.
2. The preparation method according to claim 1, characterized in that, The main chain extender accounts for 80-100% of the total molar amount of the chain extender.
3. The preparation method according to claim 1, characterized in that, The additives include matting agents, soothing agents, anti-yellowing agents, and antioxidants.
4. The preparation method according to claim 3, characterized in that, The matting agent is titanium dioxide; The relieving agent is magnesium stearate; The anti-yellowing agent is a polymer of bis(4-isocyanocyclohexyl)methane and N-tert-butyl-N,N-diethanolamine or an environmentally friendly phosphite. The antioxidant is bis[β(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] triethylene glycol ester or 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione.
5. The preparation method according to claim 3, characterized in that, The content of the matting agent is 0.2-2% of the content of the polymerization solution; The content of the decongestant is 0.1-0.5% of the content of the polymerization solution; The content of the anti-yellowing agent is 0.2-0.5% of the content of the polymerization solution; The antioxidant content is 0.6-1% of the polymer solution content.
6. The preparation method according to claim 1, characterized in that, The aging process is carried out at a temperature of 30-36℃ for 27-36 hours.
7. A three-dimensional dynamic mesh fatigue-resistant spandex fiber, characterized in that, The three-dimensional dynamic mesh fatigue-resistant spandex fiber is prepared by the preparation method described in any one of claims 1 to 6.