A number of mixtures of PTFE or TFM and inorganic fillers is offered under this heading. Of the many available options, the following fillers have shown themselves to be particularly useful:
- Glass (generally in the form of short fibers);
- Metal powders (bronze, chrome nickel steel);
- Molybdenum sulfide;
as well as mixtures of these.
Depending on the type of filler material involved and the mixture's proposed application, PTFE or TFM compounds can contain from 5 to 40 parts filler material, by volume.
Fillers can be used to achieve improvements in the following properties:
- Increased pressure resistance;
- Improved thermal conductivity;
- Increased wear resistance;
- Decreased thermal expansion.
PTFE or TFM compounds are available in free flowing and not free flowing versions. Processing is similar to that for fluoropolymers without fillers, however, higher molding pressures are required. Depending on the filler content, these pressures lie between 300 and 700 bar and, in the case of automated molding, may even rise as high as 1500 bar.
PTFE/TFM without fillers
In mechanical engineering, in electrical engineering, as insulation, in chemical equipment construction for seals and chemically resistant components, for bellows and laboratory equipment.
PTFE/TFM with carbon
For hydraulic seal elements, for parts requiring good thermal conductivity, for pressure and wear resistant parts, for bearing bushes and seals, for valve seats.
PTFE/TFM with graphite
Good thermal conductivity with adequate elasticity and good storage characteristics, for seal elements, especially lip seals.
PTFE/TFM with fiberglass
Pressure resistant, even at higher temperatures, minimum cold flow, for chemical pumps, bearing bushes, and seals.
PTFE with bronze
High pressure and wear resistance, especially well suited for bearings and guides.