Structured material having apertures and method of producing the same

A method for producing a structured composite material having a plurality of apertures for accommodation passage of fluids through the structured composite material, the method comprising the steps of:

• forming a first layer having a first shrinkage extent, said first layer comprising a fibrous thermoplastic nonwoven web;
• extruding a heat shrinkable second layer onto the first layer, the second layer comprising a thermoplastic film and having a second shrinkage extent different from the first shrinkage extent;
• forming the plurality of apertures only through the second layer after extrusion;
• and
• differentially heat shrinking the second layer relative to the first layer to increase a bulk of the composite material and produce the structured composite material;
• whereby the apertures are effective in transferring particles into the structured composite material and the first layer is effective in retaining them.