Fluoropolymer resin treatment employing melt extrusion and exposure to oxygen source to reduce discoloration

Process for reducing thermally induced discoloration of melt-processible fluoropolymer resin polymerized in the presence of hydrocarbon surfactant which causes said thermally induced discoloration and wherein all of the monovalent substituents on the carbon atoms of the hydrocarbon surfactant are hydrogen, said fluoropolymer resin having an initial thermally induced discoloration value (L*i) at least about 20 L units on the CIELAB color scale below the L* value of equivalent fluoropolymer resin of commercial quality manufactured using ammonium perfluorooctanoate fluorosurfactant, said process comprising:

• polymerizing fluoromonomer in an aqueous dispersion medium in the presence of said hydrocarbon surfactant to form aqueous fluoropolymer dispersion;
• isolating said fluoropolymer from said aqueous dispersion medium to obtain said fluoropolymer resin;
• melt extruding said fluoropolymer resin to produce molten fluoropolymer resin;
• and
• exposing said molten fluoropolymer resin to an oxygen source during said melt extruding.