B32B 3/266

Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form ; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids {; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells [CPC: B32B3/12]}