Fluoropolymers can successfully replace metals in several applications in the Chemical and in the Semiconductor Industries, thanks to their high purity, excellent chemical resistance, low permeability, high temperature resistance, low surface energy, surface smoothness, and low flammability. Some of the main applications in these fields include corrosion protection linings and construction of processing equipment, which require extensive hot gas welding of polymer sheets. Hot gas welding of fluoropolymers can be carried out by applying the same techniques used for the most common thermoplastic materials, even if proper operating conditions must be obviously selected depending on the actual polymer used. In this work the effect of some important operating parameters on the quality of fluoropolymer welds is investigated. In particular, differences when welding ECTFE (Ethylene-ChloroTriFluoroEthylene copolymers) with nitrogen or air as welding gas are analyzed. In addition, the role of different operating parameters is reviewed, with the aim of identifying conditions that guarantee the most reliable joints possible. Particular attention in this frame was devoted to correlations between optimal gas temperature and welding speed for ECTFE and PFA (PerFluoroAlkoxy) resins.
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