Method of perforating a web material

摘要

Methods are disclosed which include forming selected perforation designs and patterns. The perforation designs and patterns can be formed in linear or nonlinear fashion, can extend in the cross direction or the machine direction and can be formed to complement or match an embossed or printed design on the web. The perforation designs and patterns can be formed utilizing various mechanical perforating techniques.

主权项

1. A method of perforating a web having a first side, second side, a machine direction, a cross-machine direction orthogonal and co-planar thereto, and a Z-direction orthogonal to both the machine and cross machine directions, the method comprising the steps of:
providing a rotatable male roll having perforating elements defining web engaging edges wherein the web engaging edges of the perforating elements are spaced outwardly of an outer surface of the male roll for overstraining the web; providing a rotatable female roll having a pocket defining a web supporting edge wherein the pocket defining the web supporting edge extends inwardly of an outer surface of the female roll for receiving the web; locating the perforating elements on the male roll and the pocket in the female roll such that the pocket in the female roll will receive the perforating elements on the male roll during rotation of the male roll and the female roll; closely spacing the perforating elements from the web supporting edge by a distance selected to permit the web engaging edges to overstrain, but not cut, the web to weaken a selected area of the web without contacting the web supporting edge when the perforating elements are received in the pocket; positioning the male roll relative to the female roll so the web engaging edges extend the selected area of the web into the pocket to a predetermined depth selected to permit the web engaging edges to overstrain the web to weaken the selected area; and rotating the male roll and the female roll while transporting the web along a path extending between the male roll and the female roll to cause the pocket in the female roll to receive the perforating elements on the male roll; and, whereby a selected perforation pattern is formed by overstraining the web in the Z-direction causing individual fibers comprising the web to move apart and deflect in the Z-direction and outward from a plane formed by the machine and cross machine directions.