Thermoplastic three-dimensional fiber network

DETAILED DESCRIPTION Three dimensional fiber network structures can be made that are semi-rigid and dimensionally stable, but have sufficient flexibility to be useful as cushioning materials.
These fiber network structures are compressible, and when the compressive force is removed, the materials return to their original shape (i.
e.
they are resilient).
These fiber network structures comprise filaments that are made of a single thermoplastic polymer and do not include a thermoset polymer.
The networks are made up of a multiplicity of projections rising from the plane of the textile fabric from which the fiber network is made.
Projections are portions of the textile fabric that rise above the base plane, generally in an abrupt way.
Depressions, which are projections on the opposite side and in the opposite direction from the base plane, may optionally also be present.
The projections and optional depressions have retained an open fabric-like appearance, consisting of discrete filaments which are generally not bonded at the intersections where the individual filaments cross over one another.
There may be bonds at the intersections if the attachments are easily broken (i.
e.
they are not "tightly bonded") when the network is initially compressed, after which the network becomes resilient.
The network is "resilient" if the projections and optional depressions substantially recover their shape after being compressed to 50% of their height.
However, there may be minor changes in the shapes of the projections and optional depressions, as for example a change in the curvature of the edges at the top of the projection.
As the density of tight bonds at the points at which the fibers cross over one another increases, the fiber network structure and the projections become more rigid, and the projections lose their resilience.
Because of the open structure of the textile fabric and the large void volume within the projections and/or depressions, the network has a low density compared with the polymer (generally less than about 10%, preferably less than about 5%) based on the amount of space occupied by the network