Press felt with regenerated cellulosic scrim
A press felt for use in the press section of a papermaking machine is provided. The press felt includes a base fabric layer and at least one layer of a staple fiber batt material connected thereto. The press felt has a paper side surface (PS) which when in operation is in contact with a paper web conveyed thereon and a machine side surface (MS) which contacts various press section components. At least one scrim that includes a regenerated cellulosic fiber having a dtex from at least about 1.1 to about 44 is located between two batt layers or one batt layer and the base fabric. Felts including the scrim of regenerated cellulosic fibers provide improved dewatering when compared to similarly constructed felts which lack this regenerated cellulosic fiber batt material.
1 . A press felt for use in the press section of a papermaking machine, the press felt comprising:
a base fabric layer;
at least two layers of a staple fiber batt material connected to the base fabric layer, the press felt having a paper side surface (PS) which when in operation is in contact with a paper web conveyed thereon and a machine side surface (MS) which contacts various press section components, the staple fiber batt material is comprised of polymeric staple fibers having a dtex from at least about 1.1 to about 44; and
at least one scrim comprised of regenerated cellulosic material fibers located on the PS of the press felt between the at least two layers of staple fiber batt material or between the base fabric layer and one of the layers of staple fiber batt material, the regenerated cellulosic material fibers having a dtex of from about 1.1 to about 44.
2 . A press felt according to claim 1 , wherein the polymeric staple fibers and the regenerated cellulosic fibers have an approximately equal size.
3 . A press felt according to claim 2 , wherein the polymeric staple fiber yarn is nylon.
4 . A press felt according to claim 1 , wherein the scrim is comprised of between 20% to 80% by weight of the regenerated cellulosic fibers and from 80% to 20% by weight of a polymeric fiber.
5 . A press felt according to claim 1 , wherein the at least one scrim comprised of the regenerated cellulosic material comprises a plurality of scrims comprised of the regenerated cellulosic material, at least one of the scrims being located between adjacent batt layers or between one of the batt layers and the base fabric layer.
6 . A press felt according to claim 5 , wherein the regenerated cellulosic fibers in the scrim closest to the PS of the press felt has a smaller size than the regenerated cellulosic fibers of the scrim located closer to the base fabric.
7 . A press felt according to claim 6 , wherein the regenerated cellulosic fibers in the scrim closest to the PS have a dtex of about 2 to about 6, and the regenerated cellulosic fibers of the scrim located closer to the base fabric have a dtex of about 8 to about 20.
8 . A press felt according to claim 1 , wherein the the staple fiber batt material and the scrim is connected to the base fabric layer by a needling process.
9 . A press felt according to claim 1 , wherein a weight of the regenerated cellulosic fiber in the at least one scrim in the press felt is from about 75 to about 1000 gsm (grams per square meter).
10 . A press felt according to claim 1 , wherein a weight of the regenerated cellulosic fiber in the at least one scrim in the press felt is from about 300 to about 700 gsm.
11 . A press felt according to claim 1 , wherein the regenerated cellulosic fiber is viscose rayon.
12 . A press felt according to claim 1 , wherein the regenerated cellulose fiber is non-fibrillatable.
13 . A press felt according to claim 1 , wherein the scrim is a woven fabric and the regenerated cellulosic fibers extend in a cross direction (CD).
14 . A press felt according to claim 13 , wherein the scrim includes multifilaments that extend in the CD, at least a portion of said multifilaments are comprised of the regenerated cellulosic fibers.
15 . A press felt according to claim 13 , wherein the multifilaments that include the regenerated cellulosic fibers extend in both the CD and machine direction (MD).
16 . A press felt according to claim 1 , wherein the scrim comprises a nonwoven mesh comprising the regenerated cellulosic fibers.
17 . A press felt according to claim 16 , wherein the scrim comprises a blend of polymeric fibers and the regenerated cellulosic fibers.
18 . A press felt according to claim 1 , further comprising a hydrophobic surface treatment to at least one of the regenerated cellulosic staple fibers and the press felt.
19 . A press felt according to claim 1 , wherein the scrim further comprises a melt fuseable polymeric bi-component fiber.