Westvaco Corporation

Bryan J Ortman

David B Cason

S Craig Petro

Eric D Johnson

Hiawatha P Watkins

Paul A Huijing

Douglas W Donigian

Suzanne S Fenton

A paper rawstock web is wet densified on a papermachine at a moisture content greater than about 20% and less than about 50%, and preferably from about 25-35%, in a calender device at nip pressures greater than about 3000 psi, and preferably within the range of from about 3000-6000 psi, to provide fiber springback resistance and irreversibly smooth surfaces which are substantially resistant to loss of smoothness upon rewetting, as for example in a subsequent surface sizing or coating process. Wet densification according to the present invention produces a web having greater density and increased internal bond strength, as compared with webs treated by conventionally known methods, to achieve the irreversibly smooth surfaces.

Method for providing enhanced smoothness for a paper web

Web offset printing paper having a high level of gloss and smoothness is prepared by finishing a paper web, either by supercalender or with a synthetic roll calender at a moisture content greater than the moisture content typically used for web offset finishing, and then drying the web to a moisture content of less than about 3.5% using convection, radiation or conduction. Under the preferred post-drying conditions, bonding of the previously wet paper fibers takes place to lock in the desirable printing characteristics and to prevent heat roughening on the offset press.

Method for improving the printability of web offset paper

Growing community of inventors

Columbia, MD, United States of America

Bryan J Ortman