Method of texturing untextured dry sanitary tissue web

Claim 1

A method of producing bulky, soft sanitary tissue, comprising: providing in a continuous strip a low bulk dry untextured tissue sheet web of about 0.115 mm thickness from a water slurry of tissue quality cellulose fibers hydrogen bonded by drying of the web to from about 85% to 97% dry condition; providing cooperating grooved rotary texturing rolls each of which has generally radially projecting texturing ribs separated by grooves, the ribs on each of the rolls being the same and having from 4 to 30 equally spaced ribs per centimeter measured across the ribs, each rib being of generally triangular shape with a line contact crest; orienting said rolls in nip relation with the texturing ribs and grooves of each roll partially interdigitated with the ribs and grooves of the other of the rolls, and with the spacing between the partially interdigitated ribs greater than the thickness of said web; guiding said dry web under running tension through the rib and groove nip of said rolls; effecting longitudinal running of said dry web and rotation of said rolls at a common speed; thrusting said rib crests into the opposite faces of the running dry web and effecting progressive wave-stretch deformation of the web areas engaged by the thrusting crests out of the original plane of the tensioned web, and thereby mechanically breaking the hydrogen bond of and partially loosensing some of the fibers of the dry web and texturing and imparting desired tissue bulk and softness to the running dry web while retaining satisfactory web integrity, and elasticity and breaking length characteristics in the textured web; and after said stretch deformation releasing said web areas from said rib crests and permitting said web areas to return elastically toward said original plane of the web; whereby, the loosened fibers at both faces of the web provide a fluffiness which imparts the desired bulk and softness to the textured dry web.

Claim 2

A method of producing bulky, soft sanitary tissue, comprising: providing in a continuous strip a low bulk dry untextured tissue sheet web of about 0.115 mm thickness from a water slurry of tissue quality cellulose fibers hydrogen bonded by drying of the web to from about 85% to 97% dry condition; providing cooperating grooved rotary texturing rolls each of which has generally radially projecting texturing ribs separated by grooves, the ribs on each of the rolls being the same and having from 4 to 30 equally spaced ribs per centimeter measured across the ribs, each rib being of generally triangular shape with a line contact crest; orienting said rolls in nip relation with the texturing ribs and grooves of each roll partially interdigitated with the ribs and grooves of the other of the rolls, and with the spacing between the partially interdigitated ribs greater than the thickness of said web; guiding said dry web under running tension through the rib and groove nip of said rolls; effecting longitudinal running of said dry web and rotation of said rolls at a common speed; thrusting said rib crests into the opposite faces of the running dry web and effecting progressive wave-stretch deformation of the web areas engaged by the thrusting crests out of the original plane of the tensioned web, and thereby mechanically breaking the hydrogen bond of and partially loosensing some of the fibers of the dry web and texturing and imparting desired tissue bulk and softness to the running dry web while retaining satisfactory web integrity, and elasticity and breaking length characteristics in the textured web; and after said stretch deformation releasing said web areas from said rib crests and permitting said web areas to return elastically toward said original plane of the web; whereby, the loosened fibers at both faces of the web provide a fluffiness which imparts the desired bulk and softness to the textured dry web.