Polybutylene Terephthalate (PBT) is a high-performance engineering plastic with excellent mechanical properties, heat resistance, chemical resistance and electrical insulation, which is widely used in automotive, electrical and electronic, mechanical, chemical and other fields. In this article, the manufacturing method of polybutylene terephthalate will be introduced in detail.
I. Raw material preparation
1. Terephthalic Acid (TPA): Terephthalic Acid is the main raw material for the production of PBT, and fine terephthalic acid (PTA) is usually used as raw material.
2. 1,4-Butanediol (1,4-Butanediol, referred to as BDO): 1,4-Butanediol is another major raw material for the production of PBT, used to react with Terephthalic Acid to produce PBT.
2. Esterification Reaction
TPA and BDO will be added into an esterification reactor in accordance with a certain molar ratio, and usually adopts the batch type or continuous type of esterification reactor. Under the action of catalyst, TPA and BDO undergo esterification reaction to produce dibutyl terephthalate (BTD). The esterification reaction needs to be carried out at a certain temperature and pressure to ensure the smooth progress of the reaction. At the same time, the acidity and moisture of the reaction system need to be controlled to avoid the occurrence of side reactions.
Third, polycondensation reaction
After the esterification reaction, the generated BTD is transferred to the polycondensation reactor for polycondensation reaction. The polycondensation reaction is carried out under high temperature and high vacuum to promote the polycondensation reaction between BTD molecules by removing the water generated by the reaction to generate high molecular weight PBT. the polycondensation reaction needs to control the reaction temperature and vacuum to ensure the molecular weight and molecular weight distribution of the product.
Four, post-processing
After the end of the polycondensation reaction, the obtained PBT is subjected to post-processing, including granulation, drying, packaging and other processes. Granulation is to cut PBT into certain length and shape of particles to facilitate subsequent processing; drying is to remove the water in PBT to avoid affecting its processing performance; packaging is to protect the product for easy transportation and storage.
In short, the manufacture of polybutylene terephthalate needs to go through the processes of raw material preparation, esterification reaction, polycondensation reaction and post-treatment. During the production process, the process parameters of each process need to be strictly controlled to ensure the quality and performance of the product. Attention also needs to be paid to safe production and environmental requirements to ensure the safety and sustainability of the production process.
