Process for perforating a web
Methods for perforating web products are disclosed that 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.
1. A method of perforating a web having a Z-direction, a cross direction, and a machine direction, the method comprising the steps of:
providing a discrete web perforator for forming individual perforations comprising fibers of the fibrous web;
providing at least one additional web perforator for forming individual perforations comprising fibers of the fibrous web overstrained and extending in the Z-direction extending generally in the machine direction of the web;
providing the discrete web perforator as a female roll having a pocket disposed in an outer surface thereof and a male roll having a plurality perforating elements extending outwardly from an outer surface thereof;
having the perforating elements define web contacting edges and being positioned to be received within the pocket to produce the individual perforations in the fibrous material extending in the cross direction;
closely spacing the perforating elements from the pocket by a distance selected to permit the perforating elements and the pocket to overstrain, but not cut, the fibrous web when disposed therebetween;
transporting the web past the discrete web perforator and the at least one additional web perforator so the perforating elements extend a selected area of the web into the pocket to a predetermined depth causing fibers comprising the web to move apart and deflect in the Z-direction and outwardly from a plane formed by the machine and cross directions to form the individual perforations in the fibrous material extending generally in the cross direction;
configuring the discrete web perforator and the at least one additional perforator to form the individual perforations in the fibrous material extending generally in the cross direction to produce a selected perforation design; and
controlling the discrete web perforator and the at least one additional perforator to thereby produce the selected perforation design.
2. The method of claim 1 wherein at least one of the discrete web perforator and the additional web perforator comprises a rotatable ring roll having a circumferential groove extending about an outer surface thereof and a rotatable pattern roll having a plurality of circumferential protrusions, the circumferential protrusions extending from an outer surface of the rotatable pattern roll and being cooperatively aligned with the circumferential groove for penetrating the fibrous material of the web to produce the individual perforations in the fibrous material extending in at least one of the cross direction and the machine direction, respectively.
3. The method of claim 1 wherein at least one of the discrete web perforator and the additional web perforator comprises a plurality of individual liquid printing devices for printing a liquid onto the fibrous material of the web in at least one of the cross direction and the machine direction.
4. The method of claim 1 wherein the at least one additional web perforator comprises a rotary cutting die forming a line of the individual perforations in the fibrous material extending generally in the machine direction of the web and generally perpendicular to the individual perforations in the fibrous material extending generally in the cross direction of the web.
5. The method of claim 1 wherein the selected perforation design is nonlinear at least in the cross direction.
6. A method of perforating a web having a Z-direction, a cross direction, and a machine direction, the method comprising the steps of:
providing a discrete web perforator for forming individual perforations comprising fibers of the fibrous web overstrained, but not cut, and extending in the Z-direction and outwardly from a plane formed by the machine and cross directions and extending generally in the cross direction of the web to be converted into a through air dried perforated product;
providing at least one additional web perforator for forming individual perforations comprising fibers of the fibrous web overstrained and extending in the Z-direction extending generally in the machine direction of the web;
providing the discrete web perforator as a female roll having a pocket disposed in an outer surface thereof and a male roll having a plurality perforating elements extending outwardly from an outer surface thereof;
having the perforating elements define web contacting edges and being positioned to be received within the pocket at a predetermined depth selected to permit the perforating elements to extend, but not cut, a selected area of the web into the pocket to a predetermined depth to produce the individual perforations in the fibrous material extending in the cross direction;
transporting the web past the discrete web perforator and the at least one additional web perforator causing fibers comprising the web to move apart and deflect in the Z-direction and outwardly from a plane formed by the machine and cross directions to form the individual perforations in the fibrous material extending generally in the cross direction;
configuring the discrete web perforator and the at least one additional perforator to form the individual perforations in the fibrous material extending generally in the cross direction to produce a selected perforation design;
controlling the discrete web perforator and the at least one additional perforator to thereby produce the selected perforation design; and
embossing or printing an aesthetic pattern on the web as the web is transported past the discrete web perforator.
7. The method of claim 6 wherein at least one of the discrete web perforator and the additional web perforator comprises a rotatable ring roll having a circumferential groove extending about an outer surface thereof and a rotatable pattern roll having a plurality of circumferential protrusions, the circumferential protrusions extending from an outer surface of the rotatable pattern roll and being cooperatively aligned with the circumferential groove for penetrating the fibrous material of the web to produce the individual perforations in the fibrous material extending in at least one of the cross direction and the machine direction, respectively.
8. The method of claim 6 wherein at least one of the discrete web perforator and the additional web perforator comprises a plurality of individual liquid printing devices for printing a liquid onto the fibrous material of the web in at least one of the cross direction and the machine direction.
9. The method of claim 6 wherein the at least one additional web perforator comprises a rotary cutting die forming a line of the individual perforations in the fibrous material extending generally in the machine direction of the web and generally perpendicular to the individual perforations in the fibrous material extending generally in the cross direction of the web.
10. The method of claim 6 wherein the selected perforation design is nonlinear at least in the cross direction of the web.
11. The method of claim 6 wherein the selected perforation design matches the aesthetic pattern in the cross direction.