Polyamide (PA resin)

Polyamide is generally produced through condensation reactions between diamines and dicarboxylic acids, or through ring-opening polymerization of lactams, such as caprolactam for PA6. These polymerization processes result in long-chain polymers with repeating amide (–CONH–) units, giving polyamides their characteristic strength, thermal resistance, and durability. Different synthesis methods lead to various types of polyamide resins, such as PA6 and PA66, each exhibiting distinct melting points, crystallinity, and mechanical properties.

After polymerization, the molten polyamide is typically extruded through a die to form strands. These strands are then rapidly cooled—usually in a water bath—to solidify the material. Once cooled, the strands are fed into a pelletizer, which cuts them into uniform cylindrical or lenticular pellets. These pellets are then dried to remove moisture and packaged for storage or downstream processing, such as injection molding or extrusion. The pellet form ensures ease of handling, consistent feeding in processing equipment, and stable material quality.