PA（Polyamide series）

The main raw materials are either lactams or the polycondensation products of diamines and dibasic acids. Different varieties have different preliminary processes, which involve ring-opening initiation or concentrated salt formation, followed by tube reactor reaction, pre-polymerization, post-polymerization, and other processes to obtain the final product. Some specifications require further melting and viscosity enhancement or solid-phase polymerization. They are widely used in fibers, plastics, electronics, and many other fields.

Production facilities are categorized into batch and continuous types. The batch type mainly includes double-reactor systems. Continuous production primarily employs a four-reactor process, with ultra-high molecular weight varieties requiring additional high-viscosity polycondensation reactor units or solid-phase polymerization.