Method for the production of a roof underlay

摘要

A method is provided for the production of an active-breathing composite in the form of a web, consisting of a nonwoven made of synthetic material and a layer fully or mainly consisting of polyurethane for utilization as counter ceiling webs for roofs and as facade webs. PU or a mixture of materials with a high fraction of PU is heated to melting temperature and extruded on a nonwoven made of PP in order to form a diffusion-open coating of the PP nonwoven and then pressing the PP nonwoven in order to form an active-breathing composite.