Multilayer densified surface to improve air flow resistance and structural properties

摘要

A thermoplastic blanket includes multiple layers of thermoplastic material. The first such layer has a first surface zone, a second, optional surface zone and a first base zone between the first and second surface zones. The second layer of thermoplastic material includes a third surface zone, a fourth optional surface zone and a second base zone between the third and fourth surface zones. At least one surface zone of each layer is densified to a density of between about 1.5 to about 30.0 pcf while each base zone has a density of between about 0.5 to about 10.0 pcf.