Fluoropolymer dispersion treatment employing oxidizing agent to reduce fluoropolymer resin discoloration

Process for reducing thermally induced discoloration of fluoropolymer resin polymerized in the presence of hydrocarbon surfactant wherein all of the monovalent substituents on the carbon atoms of the hydrocarbon surfactant are hydrogen and wherein said fluoropolymer resin has an initial thermally induced discoloration value (Li) about 20 L units 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 having a raw dispersion particle size of 10 nm to 400 nm;
• exposing said aqueous fluoropolymer dispersion to oxidizing agent;
• isolating said fluoropolymer from said aqueous medium to obtain said fluoropolymer resin;
• and post-treating said fluoropolymer resin comprising exposing said fluoropolymer resin after isolation to oxidizing agent to provide an improvement over the reduction of thermally induced discoloration provided by exposing said aqueous fluoropolymer dispersion to oxidizing agent.