A PROCESS FOR MAKING IN CONTINUOUS PRODUCTION FIBROUS WEBS WHICH ARE CORRUGATED ALONG THE MACHINE DIRECTION

Process for continuously producing ribbons of corrugated fibrous material, includes:starting from a continuous ribbon of fibrous material having transversal extensibility of not less than 8%,advancing the ribbon between a pair of forming rollers presenting ribs alternating with grooves, and having a center distance such that the ribs of one roller are partially housed within the grooves of the other roller and define between them a corrugated interspace having a thickness greater than the thickness of said ribbon and a width substantially equal to the width of the flat ribbon, which at the exit presents a longitudinal undulation obtained by transversal stretching thereof,passing the longitudinally corrugated ribbon thus obtained between a pair of stabilizing rollers with complementary ribs and grooves interpenetrating such as to present a distance between them less than the thickness of the ribbon thereby subjecting the ribbon to a stabilization compression of the obtained corrugations.