Process for matting melt blow microfibers

Claim 1

A PROCESS FOR MAKING A NON-WOVEN LAMINAR STRUCTURE OF MELT-BLOWN MICROFIBERS ON A PRE-FORMED POROUS WEB COMPRISING THE STEPS OF CONTINUOUSLY PASSING A NON-WOVEN WEB UNDER TENSION OVER A SUCTION ZONE AND THEN A PRESSURE ZONE AND SUPPORTING THE WEB WHILE PASSING OVER SAID ZONES, PROVIDING A DIE HEAD HAVING A ROW OF DIE OPENINGS THEREIN FOR THE PASSAGE OF HOT GAS TO ATTENUATE MOLTEN, EXTRUDED RESIN AS FIBERS TO THE SUCTION ZONE, EXTRUDING MOLTEN THERMOPLASTIC RESIN THROUGH SAID DIE OPENINGS IN THE DIE HEAD AND SIMULTANEOUSLY PASSING A STREAM OF HOT GAS IMMEDIATELY ABOVE AND BELOW SAID ROW OF THE OPENINGS TO ATTENUATE THE MOLTEN, EXTRUDED RESIN AS FIBERS EXTENDING GENERALLY PERPENDICULAR TO THE PLANE OF THE WEB, DRAWING AIR AT AMBIENT TEMPERATURES UNIFORMLY THROUGH THE WEB IN THE SUCTION ZONE WHILE SIMULTANEOUSLY SUPPORTING THE WEB, THEN FORCING AIR THROUGH THE WEB AT PREDETERMINED TEMPERATURES SO ADJUSTED AS TO ACHIEVE A COMPOSITE MATLIKE FORM AT A REDUCED TEMPERATURE RELATIVE TO THE TEMPERATURE OF PASSAGE OF THE WEB OVER THE FIRST ZONE AND BELOW THE GLASS TRANSITION TEMPERATURE OF THE FIBERS.