Patent ID: 7671112

Claim:
Method comprising: (i) providing a fluoropolymer dispersion comprising fluoropolymer particles and one or more fluorinated surfactants selected from fluorinated carboxylic acids or salts thereof having the general formula: [R f —O-L-COO − ] i X i+ (I) wherein L represents a linear partially fluorinated alkylene group or an aliphatic hydrocarbon group, R f represents a linear partially or fully fluorinated aliphatic group or a linear partially or fully fluorinated aliphatic group interrupted with one or more oxygen atoms, X i+ represents a cation having the valence i and i is 1, 2 or 3; (ii) adding one or more non-fluorinated surfactants selected from anionic and non-ionic surfactants; and (iii) reducing the total amount of said one or more fluorinated surfactants to an amount of not more than 500 ppm based on the total weight of the dispersion while maintaining or increasing the amount of solids in the dispersion.