Extensible laminar material, in particular for sanitary articles, and relative manufacturing method

A method for producing a transversely extensible elastic laminar web material comprising the steps of:

• feeding a first web material permeable to gases having a first and a second distal region adjacent to respective longitudinal side edges and a central region between said distal regions;
• placing the first web material on an outer surface of a cylindrical roller, rotating around its own horizontal axis;
• retaining said first and second distal regions on the outer surface of said roller and keeping said first web material in an extended condition by a plurality of suction holes and a vacuum distribution system, which connect the outer surface of the roller with a sub-atmospheric pressure source;
• feeding a plurality of connection formations;
• applying said plurality of connection formations to at least one of said first and second distal regions of said first web material, said connection formations protruding from said respective longitudinal side edge of said first web material;
• holding in position on the roller said plurality of connection formations by said suction holes connected to said sub-atmospheric pressure source by said vacuum distribution system;
• feeding a web of elastomeric material;
• coupling said web of elastomeric material to said first web material at said central region of said first web material;
• holding in position and making to adhere said web of elastomeric material to the first web material by said suction holes connected to the sub-atmospheric pressure source by said vacuum distribution system;
• feeding a second web material having a first and a second distal region adjacent to the respective longitudinal side edges and a central region between said distal regions;
• coupling said second web material to said first web material with said elastomeric web material and said plurality of connection formations interposed between them;
• and
• joining said elastomeric web material and said plurality of connection formations to said first and second web materials with mechanical welds.