Process for reducing filler loss

Claim 1

In the process for preparing filled agglomerated granules of non-melt-fabricable granular tetrafluoroethylene polymer in which the filler is a particulate metal-containing filler present in an amount of between about 5 and 40% by volume of the total volume, by agitating a finely-divided blend of said polymer and said filler in which the particle size of the finely-divided tetrafluoroethylene polymer averages numerically between about 5 microns and about 200 microns and in which the filler is present in an amount of between about 5 and 40% by volume, in a two-phase liquid medium consisting essentially of water and an organic liquid which is soluble in water up to at most 15% by weight at the operating temperature of the process and which has a surface tension no greater than about 40 dynes/cm. at 25°C., and in which the organic liquid is present in an amount of 0.1 to 0.5 cc per gram of said blend, followed by separating the resulting agglomerated granules from the liquid medium; the improvement wherein said liquid medium contains an additive selected from a monocarboxylic hydrocarbon acid containing between about 12 and about 20 carbon atoms or its salt in which the cation of the salt is a Group II metal of the Periodic Table, said acid or salt being present in an amount of between 0.01 and 1 part per 1000 parts by weight of water present.