Continuous web press with a polytetrafluoroethylene composite

In a continuously operating press for pressing a web of material, the press having a press zone at an input side thereof and a calibration zone at an output side thereof and comprising:

• a lower press platen with a surface and an upper press platen with a surface confronting said surface of said lower press platen;
• means for adjusting the relative positions of said press platens and for urging them towards each other;
• a first endless band guided around said lower platen;
• a second endless band guided around said upper platen;
• means for driving said first and second endless bands at the same speed throughout said press zone and said calibration zone;
• and
• an arrangement for building up and maintaining a film of lubricant between said conforming platen surfaces and the respectively associated endless bands,
• the improvement wherein at least a portion of a surface of said press platens is comprised of a PTFE composite comprising a layer of virgin PTFE that confronts a surface of an endless band and a layer comprising filled PTFE that is attached to the press platen, the layer of filled PTFE being partially compressed at a pressure less than about 14.7 psi and the layer of partially compressed filled PTFE and the layer of virgin PTFE being compressed together and sintered.