IMPROVED DEWATERING OF A PAPER WEB IN A PRESS SECTION OF A PAPERMAKING MACHINE AND PRESS FELT THEREFOR

摘要

A press felt for use in the press section of a papermaking machine. The felt is comprised of at least one base fabric to which at least one batt layer is attached by needling or another suitable method. A woven or nonwoven fibrous scrim may be included between the base fabric and the at least one layer of batt material, or between any two or more layers. At least one of the base fabric, the at least one layer of batt material, or the fabric scrim is comprised of polymeric fibers which are blended with fibers whose modulus of elasticity is substantially less than the modulus of elasticity of the polymeric fibers. Press felts manufactured in accordance with the teachings of the invention provide a retarded elastic spring-back in the vertical (or Z) direction of the felt following the mid-nip point in the press section. This retarded elastic spring-back advances the post nip separation position of the felt and the paper web towards the mid-nip point, thus reducing rewetting of the paper sheet. Fibers comprised of regenerated celluosics, such as viscose rayon, have proven effective for use as the low modulus of elasticity component fibers in the press fabrics of the invention.