Online aramid precipitation machine

Online aramid fiber high shear settling machine, settling fiber high-speed disperser, aramid pulp fiber high-speed settling machine, aramid fiber high-speed disperser, aramid fiber online dispersion settling machine

The preparation techniques of aramid pulp mainly include PPTA concentrated sulfuric acid liquid crystal spinning cutting method and low-temperature solution condensation method. The spinning and cutting process is mature, and the resulting pulp has stable properties. However, concentrated sulfuric acid severely corrodes equipment, and the processing technology is complex. In addition, PPTA filament has extremely high strength and requires special cutting equipment, resulting in high industrial costs. At the same time, during the process of fibrillation and tapping, the fiber surface is damaged, affecting the performance of pulp.

1) Using p-phenylenediamine, p-phenylbenzoyl chloride, and R3 monomer as raw materials, DMAC as the solvent, lithium chloride as the co solvent, and low-temperature co polymerization to prepare a synthetic solution of aramid III resin, with lithium hydroxide as the HCl neutralizing agent; 2) Dilute the resin solution with DMAC solvent; 3) Mix water and DMAC solvent evenly to prepare a coagulation solution; 4) The solidified liquid and diluted resin solution are separately sent to the third stage gearHigh speed shear settling machineAfter intersecting and diffusing, and being sheared by the toothed disc, a precipitated fiber suspension is formed, which flows automatically into the solidification tank; 5) Curing to obtain wet based precipitated fiber semi-finished products; 6) Dehydration and drying yield the finished product. This method is applicable as a composite reinforcement, modified with other special polymer resins for granulation, and used for the production of various structural components through pellet injection molding, expanding the application scope of aramid III.

(1) Preparation of aromatic polyamide stock solution: Aromatic diamine and aromatic dimethylformamide are polymerized in a solvent, and after neutralization and filtration, aromatic polyamide stock solution is obtained; (2) Preparation of precipitation solvent: Mix and compound water, DMAC, and chloride salt, stir evenly after mixing; (3) Preparation of sedimented fibers: The aromatic polyamide raw liquid and the sedimented solvent are introduced into the sedimenting equipment, and the sedimented fibers are formed by high-speed shearing of the sedimenting equipment, and then discharged into the discharge tank for further cooling and shaping; (4) Post treatment of precipitated fibers: After cooling and forming, the precipitated fiber mixture containing solvent is washed and the solvent is removed to obtain the precipitated fiber product.

Aromatic meta polyamide thin film fibers refer to a dispersion system in which insoluble solid particles are dispersed in a liquid medium.During the dispersion process, it is often necessary to reduce solid particles, which is known as wet grinding or high shear dispersion. Using a SID high shear disperser to input a large amount of energy can achieve our goal.

Research and preparation of aramid precipitation

Due to the complex two-step spinning process of aramid, the production cost is relatively high. Due to the corrosive nature of sulfuric acid, high equipment requirements are required, and residual concentrated sulfuric acid can cause polymer degradation during the spinning process, which limits the strength and modulus of the fibers. In order to shorten the process and simplify the technology, Shanghai Sijun and a certain company have explored a new process of directly spinning fibers from polymer raw liquid and coagulation liquid.

The direct fiber forming process used for down like short fibers prepared by a certain company, due to the rigidity of molecular chains and their lyotropic liquid crystalline properties, can easily form anisotropic textures under the action of shear forces in solution. The Taicang Xide Mechanical High Shear Aramid Settling Machine has high shear force, which quickly mixes and disperses the high modulus liquid crystalline solution and solvent into the chamber for shearing, and adjusts the speed to the working speed. At the same time, two metering pumps are turned on to start the fibrosis reaction. After hardening, the fibers are refined to the required size of pulp through the dispersing disc to obtain high-performance aramid fiber pulp. The equipment is much better than the commonly used gear pump for extrusion stretching, spinning, and solidification from sulfuric acid solidification liquid, which has advantages in both efficiency and high modulus comparison.

The structure of the aramid fiber settling machine: XLC2000 is equipped with a specially designed screw rotor, mixing head, and dispersing head. As shown in the figure above, the solidification liquid is fed into the vertical material inlet, and the aramid raw liquid is fed into the side material inlet. The working principle is to use the high-speed rotation of a special screw rotor to generate suction, and continuously and uniformly introduce the high modulus liquid crystal raw material into a rapidly flowing precipitant. After mixing and reacting in a shear chamber, it is instantly sheared and dispersed, precipitating down like short fibers. Since the mixed liquid and the raw material are not in contact with each other before mixing, only at the moment before mixing, the raw material is dispersed and introduced into the mixed liquid, so the precipitated fibers are finer, have a larger specific surface area, and higher uniformity. The sedimentation machine is an online continuous working process that eliminates the need for tanks and other auxiliary equipment, thus saving costs and operational expenses. During the production process, XLC has great flexibility and also allows for higher material density.

Influencing factors of aramid precipitation

(1) Settling fibers are formed in a high-speed shear coagulation bath, so stable shear rate is the main factor in preparing settling fibers with stable size and performance. Therefore, equipment that generates high-speed shear can be optimized for design;
(2) Currently, the preparation of precipitated fibers is mostly done at room temperature, and by adjusting the ambient temperature, the main performance influencing factors during the formation of precipitated fibers, such as the viscosity of polymer solutions and the diffusion coefficient of coagulation baths, can be controlled.

(3) In the preparation process of precipitated fibers, the properties of polymer solution (concentration, viscosity, temperature, ion content, etc.), coagulation bath properties (solvent to coagulant ratio, coagulation bath temperature, ion concentration, etc.), and shear rate (greater than 12 s-1) are the main factors affecting the formation and properties of precipitated fibers.

XLC2000Online aramid precipitation machineParameter Table