Using Paper Compressibility Measurements to Enhance Roll Quality, 1996 Finishing and Converting Conference Proceedings

J. David Pfeiffer

JDP Innovations Inc.

High quality shipping rolls are produced when the proper roll structure is made during winding. The roll structure in turn depends upon four parameters: the MD tensile modulus, the friction coefficient of the sheet, the control of winding tension, and the z-direction compressibility of the layers of paper. The first three items have received considerable attention in the past. Measurement of the fourth parameter is only recently getting the attention it deserves, Its importance is underscored by market changes and recycling considerations that tend to dictate the blend of fibers that make up the sheet. Techniques for measuring the stress-strain response of paper samples are presented, and examples are given for modelling the behavior with compression coefficients, together with the numerical ranges expected. The relationship between variations in the compressive modulus and problems caused when there is a CD or MD variation is also discussed.