- PTFE products have excellent dielectric performances in a wide range of frequencies and temperatures. The dielectric strength changes according to the thickness and decreases when the
frequency increases, with no substantial alterations up to 260°C.
- PTFE is practically inert to all chemical products, except for some alkaline metals, for example,
clorotrifluoruro and for basic fluorine at high temperatures and pressures.
- PTFE is considered one of the most stable materials from the thermal point of view. Up to a
service temperature of 260° C PTFE does not change its own physical and molecular properties.
- The compressive strength at a certain predetermined compression value is one of the most
significant mechanical characteristics of PTFE, in a wide range of service temperatures. Flexibility
strength, plastic memory and hardness, are additional characteristics of PTFE products.
- There are five basic technicques:
1. COMPRESSION MOULDING
It is the most used processing method by which small or massive cylindrical, rectangular and sheet
shapes of PTFE are moulded at room temperature and sintered in electrical ovens.
2. AUTOMATIC MOULDING
It is usually utilized for mass production of small parts with fairly simple geometry.
3. HOT COMPRESSION MOULDING
PTFE can be compression moulded under pressure and heat applied simultaneously followed by
cooling. This process can be used to produce unfilled and filled resins almost free from porosity
and with enhanced mechanical properties.
4. ISOSTATIC MOULDING
In contrast to standard compression moulding process, isostatic pressing, thanks to elastic mould,
achieves compaction from all directions. With this process also complicated shapes can be
processed and the final part shows isotropic properties.
5. RAM EXTRUSION
It is the only continuous process for manufacturing cylindrical parts and simple profile. Compaction
and sintering steps are performed simultaneously into the extruder. In general extruded parts are
less performant in comparison to compression moulded parts.