US 11,781,270 B2
Methods of making multi-ply fibrous sheets
Peter Gordon Anderson, De Pere, WI (US); Frank D. Harper, Nennah, WI (US); and Nathan Capps, Appleton, WI (US)
Assigned to GPCP IP Holdings LLC, Atlanta, GA (US)
Filed by GPCP IP Holdings LLC, Atlanta, GA (US)
Filed on May 17, 2021, as Appl. No. 17/321,705.
Application 17/321,705 is a division of application No. 16/257,349, filed on Jan. 25, 2019, granted, now 11,035,078.
Claims priority of provisional application 62/639,559, filed on Mar. 7, 2018.
Prior Publication US 2021/0277603 A1, Sep. 9, 2021
Int. Cl. D21F 11/14 (2006.01); D21H 21/20 (2006.01); D21F 11/00 (2006.01); D21H 27/00 (2006.01); D21F 3/02 (2006.01)
CPC D21F 11/145 (2013.01) [D21F 3/02 (2013.01); D21F 11/006 (2013.01); D21H 21/20 (2013.01); D21H 27/005 (2013.01)] 32 Claims
OG exemplary drawing
 
1. A method of making a multi-ply fibrous sheet, the method comprising:
providing, from a first furnish including a primary pulp having papermaking fibers, a first ply including a first stratified base sheet, the first stratified base sheet having at least two layers, one of the at least two layers being an inner layer, and another of the at least two layers being an outer layer comprising papermaking fibers, at least about eighty percent of the papermaking fibers in the outer layer being softwood fibers, the softwood fibers of the outer layer having (i) a weight-weighted average fiber length between about two and seven tenths millimeters and about three millimeters and (ii) a coarseness of about sixteen milligrams per one hundred meters or lower, the outer layer including a wet strength resin and the inner layer being substantially free of the wet strength resin;
providing, from a second furnish including a pulp having papermaking fibers, a second ply including a second stratified base sheet, the second stratified base sheet having at least two layers, one of the at least two layers being an inner layer, and another of the at least two layers being an outer layer comprising papermaking fibers, at least about eighty percent of the papermaking fibers in the outer layer being softwood fibers, the softwood fibers of the outer layer having (i) a weight-weighted average fiber length between about two and seven tenths millimeters and about three millimeters and (ii) a coarseness of about sixteen milligrams per one hundred meters or lower, the outer layer including a wet strength resin and the inner layer being substantially free of the wet strength resin;
forming a nascent web having at least two layers by arranging the first ply and the second ply such that the inner layer of the first ply is adjacent to the inner layer of the second ply and the inner layer of the first ply is attached to the inner layer of the second ply;
dewatering the nascent web to form a dewatered web;
applying the surface layer of the dewatered web to the outer surface of a Yankee drum of a Yankee dryer; and
drying the dewatered web with the Yankee dryer to form the multi-ply fibrous sheet,
wherein the multi-ply fibrous sheet has a cross machine direction (CD) wet/dry tensile ratio between about twenty-five hundredths and about thirty-five hundredths.