The present invention belongs to the technical field of polymer materials, and specifically discloses a preparation process of a halogen-free flame-retardant polybutylene terephthalate (PBT). Raw materials are fed into a twin-screw extruder for melt mixing and extrusion pelletization to obtain the halogen-free flame-retardant PBT. The raw materials comprise, by mass percentage: 46%–52% of PBT resin particles, 0.2%–0.3% of a coupling agent, 0.2%–0.5% of an antioxidant, 0.2%–0.5% of a lubricant, 2%–3% of a toughening agent, 28%–30% of glass fiber, 8%–11% of melamine polyphosphate (MPP), and 8%–11% of hypophosphite. The twin-screw extruder sequentially comprises a feeding section, a melt plasticization section, a mixing section, a ash removal section and an extrusion section along the material conveying direction. The screw elements of the mixing section sequentially comprise a forward conveying unit, a shearing unit, a conveying unit, a shearing unit, a conveying unit, a stretching block, a reverse stretching block and a conveying unit along the material conveying direction. A main feeding port is arranged on the feeding section, and a side feeding port is arranged on the mixing section. The PBT resin particles, coupling agent, antioxidant, lubricant and toughening agent are fed from the main feeding port, and other components are stirred by a high-speed mixer and then fed together with glass fiber from the side feeding port.
Country Code: CN
Application Number: CN202410134833.0
