A ternary aramid fiber polymer solution production system suitable for dry-jet wet spinning process

Abstract

This invention discloses a production system for ternary aramid fiber polymer solutions suitable for dry-jet wet spinning processes. It employs a mixing tank, a primary screw reactor, a secondary screw reactor, and a tertiary screw reactor. The mixing tank is connected to a p-phenylenediamine monomer storage tank, a 3,4'-diaminodiphenyl ether monomer storage tank, and a composite solvent mixing tank. The primary and tertiary screw reactors are connected to a terephthaloyl chloride monomer storage tank. The solution temperature detectors of the primary, secondary, and tertiary screw reactors are interlocked with the motor speeds of their respective reactors. This invention, through the series connection of multiple screw reactors and the interlocking control of specific process parameters, can continuously and stably produce ternary aramid polymer solutions with high solids content and suitable viscosity. This solves the problems of poor product stability and low wet spinning efficiency in existing batch reactor polymerization, while also meeting the requirements of subsequent dry-jet wet spinning processes.

Description

Technical Field

[0001] This utility model belongs to the field of special fiber material preparation technology. Specifically, it is a production system for ternary aramid fiber polymer solution suitable for dry-jet wet spinning process. Background Technology

[0002] Ternary aramid (aromatic polyamide) is a high-performance fiber synthesized by copolymerization of a third monomer into para-aramid. Compared to traditional para-aramid, ternary aramid exhibits significant advantages in specific strength, specific modulus, elongation at break, dimensional stability, and high-temperature resistance. The flexible structural units introduced into its molecular chain endow it with excellent fatigue resistance and abrasion resistance, exhibiting less performance degradation under cyclic loading and a longer service life. Therefore, ternary aramid is widely used in high-performance ropes, rubber transmission belts, friction sealing materials, aircraft structural components, rocket casings, protective equipment, and sporting goods.

[0003] Currently, the production of multi-component aramid fibers in China generally adopts a low-temperature solution batch polymerization process. The polymer solution is directly used for wet spinning after treatment. However, this process has significant limitations: firstly, the molecular weight of the polymerization products varies significantly between batches, making it difficult to guarantee the consistency of fiber quality; secondly, the low wet spinning speed, typically only 10–30 m / min, restricts fiber production efficiency. These factors combined make it difficult to improve product stability and production efficiency, severely hindering the large-scale and low-cost development of this fiber.

[0004] To address the shortcomings of traditional batch polymerization processes in terms of production efficiency and product stability, Chinese patent CN120209296A proposes a continuous polymerization process for preparing multi-component aramid copolymers. This process first dissolves an aromatic diamine monomer in an amide or amide / co-solvent complex solvent to form a premix. Then, at -10 to 0°C, it undergoes low-temperature prepolymerization with a portion of terephthaloyl chloride in a continuous mixer or microtubular reactor to form a prepolymer. Next, the remaining terephthaloyl chloride is added through a twin-screw or biaxial reactor, and low-temperature polycondensation is completed under high-speed shear to obtain polymer powder or polymerization solution with an intrinsic viscosity greater than 4.5 dL / g. Finally, after neutralization, washing, drying or degassing, and filtration, the resulting product can be directly used for wet spinning or spun using a sulfuric acid liquid crystal wet-dry process. Therefore, this continuous polymerization process, through optimized reactor combination and process design, achieves a highly efficient and stable preparation process for multi-component aramids.

[0005] It is evident that the existing technologies for preparing ternary aramid polymer solutions are mainly designed for wet spinning or liquid crystal spinning processes based on concentrated sulfuric acid solvents, and are not applicable to dry-jet wet spinning processes. Furthermore, there is currently no production system for ternary aramid fiber polymer solutions specifically designed for the characteristics of dry-jet wet spinning processes, especially lacking systematic and continuous solutions in terms of solution solid content and viscosity control. Utility Model Content

[0006] The purpose of this invention is to provide a ternary aramid fiber polymer solution production system suitable for dry-jet wet spinning process. By connecting multiple screw reactors in series and coordinating with the interlocking control of specific process parameters, it can continuously and stably prepare ternary aramid polymer solutions with high solid content and suitable viscosity to meet the requirements of subsequent dry-jet wet spinning process. This effectively solves the problems of poor product stability and low wet spinning efficiency in existing batch reactor polymerization.

[0007] This invention is achieved through the following technical solution: a ternary aramid fiber polymer solution production system suitable for dry-jet wet spinning process, comprising a mixing solution preparation tank, a first-stage screw reactor, a second-stage screw reactor, and a third-stage screw reactor connected in sequence. The mixing solution preparation tank is connected via pipelines to a p-phenylenediamine monomer storage tank, a 3,4'-diaminodiphenyl ether monomer storage tank, and a composite solvent preparation tank, respectively. The first-stage and third-stage screw reactors are connected via pipelines to a terephthaloyl chloride monomer storage tank, respectively. Solution temperature detectors are installed on the first-stage, second-stage, and third-stage screw reactors, respectively, and the solution temperature detectors of each stage of the screw reactor are interlocked with the motor speed of the corresponding screw reactor.

[0008] A calcium chloride solution inlet pipe and an N-methylpyrrolidone inlet pipe are respectively installed on the composite solvent preparation tank. The regulating valve of the calcium chloride solution inlet pipe and the regulating valve of the N-methylpyrrolidone inlet pipe are interlocked to ensure the precise control and stability of the composite solvent composition.

[0009] Four regulating valves are installed on the connecting pipelines of the mixed liquid preparation tank and the p-phenylenediamine monomer storage tank, the mixed liquid preparation tank and the 3,4'-diaminodiphenyl ether monomer storage tank, the terephthaloyl chloride monomer storage tank and the first-stage screw reactor, and the terephthaloyl chloride monomer storage tank and the third-stage screw reactor, respectively. The four regulating valves are interlocked to achieve precise proportioning of each monomer material.

[0010] A mixture storage tank is provided between the mixture preparation tank and the first-stage screw reactor for buffering and storing materials, ensuring continuous supply. The mixture preparation tank, mixture storage tank and compound solvent preparation tank are all vessel structures with internal agitators to ensure uniform mixing of materials.

[0011] The p-phenylenediamine monomer storage tank, 3,4'-diaminodiphenyl ether monomer storage tank, composite solvent preparation tank, mixed liquid preparation tank, mixed liquid storage tank, and terephthaloyl chloride monomer storage tank are all connected to a nitrogen gas source via pipelines to provide inert gas protection for the entire system and prevent material oxidation.

[0012] Compared with the prior art, this utility model has the following advantages and beneficial effects: (1) This utility model achieves continuous production from monomer mixing to polymer solution formation through the combination design of a mixing tank and a three-stage series screw reactor, effectively overcoming the batch difference of batch polymerization and ensuring the stability of product quality.

[0013] (2) This invention achieves precise control of shear and mixing intensity during the reaction process by setting up a solution temperature detector and interlocking control of the corresponding screw reactor motor speed, ensuring that each stage of the reaction is within the optimal process window. The solid content (5-15%), dynamic viscosity (6-400,000 centipoise), and molecular weight distribution of the ternary aramid polymer solution prepared in this way are effectively controlled, which not only meets the strict requirements of dry-jet wet spinning process, but also realizes direct application from polymerization solution to spinning, eliminating the complicated steps of traditional acid hydrolysis to prepare liquid crystal spinning solution.

[0014] (3) This utility model ensures the precise proportion of reaction monomers (p-phenylenediamine, 3,4'-diaminodiphenyl ether and terephthaloyl chloride) by interlocking the regulating valves of key material pipelines, thus guaranteeing the fullness and uniformity of the polymerization reaction from the source and laying the foundation for obtaining high-performance polymer solutions.

[0015] (4) The system structure of this utility model is reasonably designed and has a high degree of automation. It not only provides a stable and reliable raw material solution for dry-jet wet spinning of ternary aramid fibers, but also helps to improve spinning efficiency, reduce production costs, and promote the large-scale application of high-performance aramid fibers. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system flow of this utility model.

[0017] Among them, 1—solution temperature detector, 2—motor. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0019] Example 1: This embodiment relates to a continuous production system for ternary aramid fiber polymer solutions suitable for dry-jet wet spinning. It aims to address the shortcomings of existing batch polymerization processes in terms of product stability and production efficiency. The system first achieves continuous material transport and reaction throughout the entire process through a mixing tank and a three-stage series screw reactor. Furthermore, specific interlocking controls are implemented on the multi-stage screw reactor to precisely regulate process parameters (solution temperature and screw speed), thereby consistently producing polymer solutions with satisfactory properties (such as solid content and dynamic viscosity). This solution can be directly used for dry-jet wet spinning without additional treatment, significantly improving spinning rate and overall production efficiency.

[0020] See Figure 1 As shown, this embodiment mainly involves the following equipment and process flow: p-Phenylenediamine monomer storage tank: used to store p-phenylenediamine (PPDA) monomer.

[0021] 3,4'-Diaminodiphenyl ether monomer storage tank: Used for storing 3,4'-diaminodiphenyl ether (3,4'-ODA) monomer.

[0022] Terephthaloyl chloride monomer storage tank: used for storing terephthaloyl chloride (TPC) monomer.

[0023] Composite solvent preparation tank: It is equipped with a calcium chloride solution feed pipe and N-methylpyrrolidone (NMP). Through the interlocking control of regulating valves V1 and V2, calcium chloride solution and N-methylpyrrolidone are added to the composite solvent preparation tank in proportion. After mixing and dissolving, an NMP / CaCl2 composite solvent system is formed, in which the calcium chloride content is 0.5-7wt% and the water content is ≤100ppm.

[0024] Mixing solution preparation tank: Used to mix and dissolve p-phenylenediamine monomer and 3,4'-diaminodiphenyl ether monomer in a composite solvent system. A regulating valve V3 is installed on the connecting pipeline between the mixing solution preparation tank and the p-phenylenediamine monomer storage tank; a regulating valve V4 is installed on the connecting pipeline between the mixing solution preparation tank and the 3,4'-diaminodiphenyl ether monomer storage tank; and a regulating valve V5 is installed on the connecting pipeline between the mixing solution preparation tank and the composite solvent preparation tank. During production, the composite solvent is added to the mixing solution preparation tank by controlling regulating valve V5. Then, the p-phenylenediamine monomer and 3,4'-diaminodiphenyl ether monomer are added to the composite system according to a set molar ratio (p-phenylenediamine: 3,4'-diaminodiphenyl ether = 70:30 to 15:85) through the interlocked regulating valves V3 and V4 to obtain a mixed solution.

[0025] Mixed solution storage tank: Used to temporarily store the mixed solution obtained from the above-mentioned mixed solution preparation tank, so as to provide a continuous and stable supply of raw materials for subsequent multi-stage screw reactors.

[0026] Multistage screw reactor: includes a first-stage screw reactor, a second-stage screw reactor and a third-stage screw reactor arranged in sequence. Solution temperature detectors 1 (T1, T2, T3) are installed on the first-stage screw reactor, the second-stage screw reactor and the third-stage screw reactor respectively. The solution temperature detectors 1 of each stage screw reactor are interlocked with the motor speed of the corresponding screw reactor. During polymerization, regulating valve V7 is opened to feed the mixed solution into the first-stage screw reactor. The temperature of the mixed solution is controlled (T1: -5~5℃). Terephthaloyl chloride is added, and the motor speed of the first-stage screw reactor is controlled (R1: 30~60r / min) for low-temperature mixing to form a prepolymer mixture. The prepolymer mixture is then fed into the second-stage screw reactor. The temperature of the prepolymer mixture is controlled (T2: 0~20℃), and the motor speed of the second-stage screw reactor is controlled (R2: 50~100r / min) for medium-speed prepolymerization to form a prepolymer stock solution. The prepolymer stock solution is then fed into the third-stage screw reactor. The temperature of the prepolymer stock solution is controlled (T3: 20~90℃). Terephthaloyl chloride is added, and the motor speed of the third-stage screw reactor is controlled (R3: 100~500r / min) for high-speed shearing and final polymerization using a third-stage twin-screw extruder to form a polymer solution.

[0027] Optionally, the first-stage screw reactor, the second-stage screw reactor, and the third-stage screw reactor are three twin-screw reactors arranged in series. The material temperature and stirring speed in the twin-screw reactors are independently controlled by a controller to achieve continuous reaction and stable control of the polymer material.

[0028] Secondly, regarding the control of terephthaloyl chloride feed, the first and second addition amounts can be adjusted using interlocked control valves V8 and V9, respectively. For example, the first addition amount of terephthaloyl chloride is 60-95% of its total addition amount, and the second addition amount is 5-40% of its total addition amount. Furthermore, considering that the feed ratio of p-phenylenediamine monomer, 3,4'-diaminodiphenyl ether monomer, and terephthaloyl chloride monomer needs to be dynamically optimized according to the reaction progress, control valves V3, V4, V8, and V9 can also be incorporated into a unified interlocked control system to achieve overall coordination and precise control of the proportions of each key monomer.

[0029] To further isolate oxygen and prevent the diamine monomer from oxidizing and deactivating during the process, the system is equipped with pipelines connected to a nitrogen source and corresponding regulating valves on the p-phenylenediamine monomer storage tank, the 3,4'-diaminodiphenyl ether monomer storage tank, the composite solvent preparation tank, the terephthaloyl chloride monomer storage tank, the mixed solution preparation tank, and the mixed solution storage tank. This ensures that all the above processes are carried out under nitrogen protection, maintaining an inert atmosphere throughout the entire material preparation and transportation process.

[0030] Based on the aforementioned composite solvent system, strictly controlled molar ratios of reaction components, continuous nitrogen protection, and the synergistic effect of a multi-stage screw continuous polycondensation process, this system successfully achieved precise control over the polymerization process, enabling the stable preparation of ternary aramid polymer solutions with a solid content of 5–15%, a dynamic viscosity of 6–400,000 centipoise, and a narrow molecular weight distribution. This solution exhibits excellent spinning adaptability, providing a crucial material foundation for subsequent dry-jet wet-spinning and the preparation of high-performance fibers.

[0031] It should be noted that this embodiment can use a controller (such as a PLC or DCS) to perform centralized interlocking control and adjustment of each execution unit, specifically including: In the compound solvent preparation stage, the controller automatically adjusts valves V1 and V2 according to the preset ratio of N-methylpyrrolidone to calcium chloride to achieve precise preparation of the compound solvent. During the reaction component feeding stage, the controller interlocks and adjusts valves V3, V4, V6, V7, V8 and V9 according to the set monomer molar ratio to ensure that each monomer is fed accurately in proportion. In terms of nitrogen protection, the regulating valves of the corresponding pipelines are automatically opened during the material addition and mixing process to maintain the system in an inert atmosphere and effectively prevent material oxidation. In the multi-stage screw continuous polycondensation process, the material temperature is collected in real time by the solution temperature detector 1 (such as an industrial-grade temperature sensor) and fed back to the controller. The controller transmits the control signal to the motor 2 of the corresponding screw reactor according to the preset temperature-speed relationship, and dynamically adjusts its motor speed to achieve stable control of the reaction process.

[0032] Example 2: This embodiment describes the specific process of preparing a ternary aramid fiber polymer solution using the system described in Example 1: (I) Preparation of polymer solutions The composite solvent system consists of N-methylpyrrolidone (water content ≤100 ppm) and calcium chloride, wherein the calcium chloride content is 2 wt%.

[0033] Monomer ratio: The molar ratio of p-phenylenediamine to 3,4'-diaminodiphenyl ether is 1:1.

[0034] The total amount of terephthaloyl chloride added is usually 1.001 to 1.005 times that of p-phenylenediamine, and it is added in two steps: the first addition is 90% of the total amount added, and the second addition is 10% of the total amount added.

[0035] (2) Polymerization process Two diamine monomers were dissolved in a composite solvent and stirred under nitrogen protection to form a homogeneous mixed solution.

[0036] The mixed solution was cooled to -5°C, and the first addition of terephthaloyl chloride was made. The mixture was then introduced into a continuous polycondensation system consisting of three series-connected screw reactors. First-stage screw reactor: rotation speed 30 r / min, temperature -5 ℃, residence time 15 min, to achieve low-temperature mixing; Two-stage screw reactor: rotation speed 50 r / min, temperature 0 ℃, residence time 15 min, to complete medium-speed pre-condensation; Three-stage screw reactor: Add the remaining terephthaloyl chloride, rotate at 400 r / min, maintain the temperature at 70 ℃, and hold for 45 min to carry out high-speed shearing and final polymerization.

[0037] The final product is a homogeneous polymer solution with a solid content of 10%, a dynamic viscosity of 310,000 centipoise at 25 °C, and a narrow molecular weight distribution.

[0038] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A polymer solution production system for ternary aramid fibers suitable for dry-jet wet spinning process, characterized in that: The system comprises a mixing tank, a first-stage screw reactor, a second-stage screw reactor, and a third-stage screw reactor connected in sequence. The mixing tank is connected via pipelines to a p-phenylenediamine monomer storage tank, a 3,4'-diaminodiphenyl ether monomer storage tank, and a composite solvent mixing tank. The first-stage and third-stage screw reactors are connected via pipelines to a terephthaloyl chloride monomer storage tank. Solution temperature detectors (1) are installed on the first-stage screw reactor, the second-stage screw reactor, and the third-stage screw reactor, respectively. The solution temperature detectors (1) of each stage screw reactor are interlocked with the motor speed of the corresponding screw reactor.

2. The production system according to claim 1, characterized in that: A calcium chloride solution inlet pipe and an N-methylpyrrolidone inlet pipe are respectively installed on the composite solvent preparation tank, and the regulating valve of the calcium chloride solution inlet pipe and the regulating valve of the N-methylpyrrolidone inlet pipe are interlocked for control.

3. The production system according to claim 1, characterized in that: Four regulating valves are installed on the connecting pipelines of the mixed liquid preparation tank and the p-phenylenediamine monomer storage tank, the mixed liquid preparation tank and the 3,4'-diaminodiphenyl ether monomer storage tank, the terephthaloyl chloride monomer storage tank and the first-stage screw reactor, and the terephthaloyl chloride monomer storage tank and the third-stage screw reactor, respectively, and the four regulating valves are interlocked for control.

4. The production system according to claim 1, characterized in that: A mixture storage tank is provided between the mixture preparation tank and the first-stage screw reactor. The mixture preparation tank, the mixture storage tank, and the composite solvent preparation tank are all vessel structures with internal agitators.

5. The production system according to claim 4, characterized in that: The p-phenylenediamine monomer storage tank, the 3,4'-diaminodiphenyl ether monomer storage tank, the composite solvent preparation tank, the mixed liquid preparation tank, the mixed liquid storage tank, and the terephthaloyl chloride monomer storage tank are all connected to a nitrogen gas source via pipelines.

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