DuPont Teflon® PTFE Grade 304A Aqueous Dispersion

Subcategory: Fluoropolymer; Thermoplastic; PTFE

Key Words: Polytetrafluoroethylene; DuPont Fluoroproducts

Material Notes:
Teflon® PTFE 304A fluoropolymer resin is a negatively charged, hydrophobic colloid containing approximately 45% (by total weight) of 0.05 to 0.5 mm polytetrafluoroethylene (PTFE) resin particles suspended in water. A milky white liquid, Teflon® PTFE 304A also contains approximately 6% (by weight of PTFE) of a nonionic wetting agent and stabilizer. It also contains a thickening agent to increase the viscosity and ethylene glycol to retard evaporation of the water and give a level coating. The viscosity at room temperature is around 1700 cP as measured on a Brookfield viscometer using a #1 spindle at 60 rpm. The viscosity of Teflon® PTFE 304A is very non-Newtonian. Measurement of the viscosity at lower spindle speeds will give higher viscosity values.

The pH of Teflon® PTFE 304A is normally above 9.5.

When properly processed, the PTFE resin in Teflon® PTFE 304A exhibits the superior properties typical of the fluoropolymer resins: retention of properties after service at 260°C (500°F), useful properties at –240°C (–400°F), chemical inertness to nearly all industrial chemicals and solvents, and low friction and antistick surfaces. Dielectric properties are outstanding and stable with frequency and temperature.

Applications

Teflon® PTFE 304A is normally used to coat gaskets. In many cases, a thick coating is applied, which is heated to remove the ethylene glycol and wetting agents but is not sintered. The thick coating cold flows when the gasket is tightened. This helps ensure a tight seal in addition to the benefits of easy removal of the gasket due to the nonstick nature of PTFE.