1. Special Process Requirements Determined by Material Properties
PTFE has no melt flowability. It remains in a highly elastic gel state above 327℃ and cannot be injection molded or melt extruded. Production adopts a powder metallurgy process combining cold pressing and sintering.
The sintering temperature ranges from 370℃ to 385℃, requiring high temperature control accuracy (±1℃). Excessive temperature will cause material decomposition and reduced mechanical strength.
With low thermal conductivity, PTFE is prone to local overheating. The heating and cooling rates must be strictly regulated to prevent internal stress, cracking and deformation.
For anti-corrosion, medical and semiconductor-grade products, the whole production process requires a clean environment to avoid metal contamination and foreign impurities.
2. Characteristics of Main Production Equipment & Processes
2.1 Polymerization Section
Equipment: High-pressure polymerization reactor, dispersion/suspension polymerization system, condensation recovery unit, washing, drying, sieving and packaging lines.
Process Features Two mainstream production routes: suspension polymerization and dispersion polymerization.
Suspension polymerization: Carried out in aqueous phase at medium temperature and pressure. Produces particles with uniform size and narrow molecular weight distribution, ideal for molded and turned PTFE products.
Dispersion polymerization: Uses fluorinated emulsifiers to obtain controllable emulsion particle size, suitable for thin-wall parts, films, coatings and fibers.
The entire system is fully enclosed, explosion-proof and oxygen-free. Strict closed-loop control is applied to pressure, temperature and stirring, as TFE monomer is prone to self-polymerization.
2.2 Molding & Preforming Equipment
Equipment: Hydraulic molding press, cold pressing machine, automatic weighing and feeding system.
Process Features Forming is completed by cold pressing at room temperature under pressure of 40–100 MPa, with no binders or additives added.