(1) Dimension Stability
Ability of felt to resist deformation in use;
(2) Permeability
It is essential to felt, presenting the difficulty level of water penetrating through felt under certain pressure;
(3) Superficiality
It means the surface finish and smoothness.
They are three key properties of felt, wherein “strength” and “Permeability” directly determine the lifespan of felt, “superficiality” is associated with paper smoothness. The three are interactional; only the optimization of the three can produce a high-quality felt.