| abstract |
A method of stabilizing these aqueous dispersions by adding macromolecular species directly to an aqueous dispersion of polytetrafluoroethylene (PTFE) or a copolymer of polytetrafluoroethylene and a terpolymer. Surprisingly, when macromolecular species are added to dispersions of PTFE, or copolymers and terpolymers of PTFE, these dispersions are very stable and do not readily solidify and remain stable even when freeze / thaw cycles are performed. The amount of macromolecular species added is, for example, approximately 0.1 wt.% To 20.0 wt.%, And suitable macromolecular species are polyacrylic acid (PAA), polyvinyl alcohol (PVOH), polyethyleneimine (PEI), polyethylene glycol ( PEG) and the like. The process according to the invention is particularly effective for stabilizing commercially available "unstable" aqueous dispersions of PTFE, or copolymers and terpolymers, containing no (or little) surfactant. |