Preparation method of mesophase pitch

Abstract

The invention discloses a preparation method of mesophase pitch, the method comprises N times of thermal polymerization reactions, N is an integer greater than 1, preferably an integer greater than 2, and further preferably 2; rapid cooling treatment is carried out after each thermal polymerization reaction; the cooling rate is 20-150 DEG C/min, preferably 50-100 DEG C/min, and the temperature is rapidly reduced to 60%-90% of the temperature of the thermal polymerization reaction, preferably 60%-90%. The method can be used for continuously producing the high-purity mesophase pitch and can be used for producing high-end carbon fibers.

Description

technical field [0001] The invention belongs to the technical field of mesophase pitch preparation, and relates to a preparation method of mesophase pitch, in particular to a preparation method of mesophase pitch used for producing high-end carbon fibers. Background technique [0002] Pitch-based carbon fiber can be divided into two categories according to its mechanical properties: one is general-purpose pitch-based carbon fiber, which has low mechanical properties and is prepared with isotropic pitch; the other is high-performance pitch-based carbon fiber, which has low mechanical properties. Excellent, with anisotropic asphalt as raw material. The latter fiber is transformed from mesophase pitch, and the orientation arrangement of the mesophase pitch macromolecules is maintained due to shear force and stretching during the spinning process, thereby producing high-strength, high-modulus carbon fibers. At the same time, it has excellent heat transfer and electrical conduct...

AI Technical Summary

Problems solved by technology

Take the distillate oil of the modified oil higher than 400°C, mix the distillate oil with a co-carbonizing agent, and react for 2-10 hours at 360-480°C, with a reaction pressure of 4-10 MPa, to obtain high-quality mesophase pitch; Japanese Patent Laid-Open Zhao 61-83317 discloses a method using AlCl 3 Catalytic reaction of aromatic compounds such as naphthalene to synthesize oligomerized pitch and obtain low softening point mesophase pitch, but AlCl 3 Reaction with bitumen makes its separation and recovery difficult, affecting the application of final mesophase pitch

[0004] Chinese patent CN101525543A discloses a preparation method of mesophase pitch. The refined naphthalene, hydrogen fluoride and boron trifluoride are mixed according to the mass ratio of 10:1~5:2~6, and sent into the polymerization kettle, and the stirring is started to control the pressure. 10~25MPa, temperature 150~200°C, react for 4~6 hours, then increase the pressure to 25~30MPa, raise the temperature to 260~310°C, continue to react for 4~6 hours to obtain mesophase pitch, but hydrogen fluoride and The corrosion of boron trifluoride to equipment is relatively serious, which not only brings problems such as operation safety protection and environmental protection, but also makes the purification of the final asphalt more difficult due to the inevitable introduction of metal ions, and also makes the process. The difficulty of industrialization is increasing. At present, almost all domestic research institutes and enterprises adopting this process route are at a stagnant stage due to the impact of safety hazards.

However, this method does not consider the poor thermal stability of mesophase pitch at high temperature. The reaction process is prone to excessive condensation, which affects the spinning performance of mesophase pitch, and ultimately cannot produce high-performance carbon fibers.

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