Preparation method of high-purity LCP material

Abstract

The invention relates to the technical field of liquid crystal polymers, in particular to a preparation method of a high-purity LCP material. The LCP material is prepared through a two-step method. Firstly, a specific catalyst is added to enable HBA / HNA and acetic anhydride to be subjected to a collaborative optimization reaction, so that complete acetylation of HBA / HNA is guaranteed to the maximum extent. Then, the ABA, ANA and catalyst after acetylation and the reaction conditions are controlled, and the purity of TLCP is improved by synergistically optimizing process parameters, so that the prepared LCP material is excellent in comprehensive performance and can better meet application requirements. In addition, the preparation method disclosed by the invention is simple in overall process and easy to operate, meets the requirements of large-batch production and manufacturing, and has a good application prospect.

Description

technical field [0001] The invention relates to the technical field of liquid crystal polymers, in particular to a preparation method of a high-purity LCP material. Background technique [0002] LCP (Liquid Crystal Polymer, liquid crystal polymer) is a kind of polymer between solid and liquid. It is a new type of polymer material, which has both the anisotropy of crystal and the fluidity of liquid. According to the physical conditions of the liquid crystal phase, LCP materials can be divided into thermotropic liquid crystal polymers (TLCP) and lyotropic liquid crystal polymers (LLCP). Liquid crystal polyesters are based on p-hydroxybenzoic acid (HBA) and 2-hydroxy- Synthesized from 6-naphthoic acid (HNA) as the main monomer, it is a typical thermotropic liquid crystal polymer (TLCP), with its unique high strength, high modulus, high heat-resistant temperature and unique rheological properties and The excellent electrical properties have attracted widespread attention from t...

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Problems solved by technology

[0003] In the prior art, the synthesis of TLCP materials of HBA / HNA liquid crystal copolyesters is carried out in two steps, first HBA and HNA are acetylated to prepare 4-acetoxybenzoic acid (ABA) and 2-acetoxy-6-naphthalene Formic acid (ANA), and then raised to a certain temperature in an inert gas atmosphere such as nitrogen to prepare TLCP materials, but the reaction of HBA / HNA TLCP materials is very complicated during the polymerization process, and HBA will desorb at 150 ° C. The acid reaction produces phenol, and the process of HBA / HNA copolymerization is not a simple acidolysis process. In the later stage of the reaction, the removal of ketene leads to the generation of phenol end groups, and the deacidification leads to the generation of phenyl ester groups. The reaction mechanism has also changed from acidolysis to phenololysis. The purity of the product after HBA / HNA acetylation will not only affect the subsequent melt polycondensation, but also affect the final TLCP performance.

If the acetylation reaction is not complete, some unreacted raw materials will participate in the melt polycondensation reaction as acetylated products, which will affect the ratio of monomers

The remaining unreacted phenolic hydroxyl groups do not participate in the transesterification reaction because the polarity of the phenolic hydroxyl group is too large. As the reaction temperature continues to rise, these raw materials will be sublimated or even carbonized in large quantities, which will seriously affect the properties of TLCP.

Since TLCP is accompanied by many side reactions during the synthesis process, there are many impurities in the prepared TLCP material, resulting in low purity, which affects the comprehensive performance of TLCP materials.

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