Study of Paper Transverse Shrinkage During Thermal Drying

Abstract

The z-direction shrinkage of laboratory papers made of bleached softwood kraft pulp subjected to drying was studied. The results showed that shrinkage was dependent on the beating level of the pulp and independent of wet pressing in the range explored. The low-basis-weight sheets had greater specific volumes than the higher-basis-weight ones due to the greater relative importance of the superficial layers compared to the bulk, but their transverse shrinkage was smaller.

Empirical correlations were proposed to model the thickness results as a function of moisture content for their interest in computational simulation of drying including shrinkage.

Keywords:

• Laboratory paper
• Thermal drying
• Transverse shrinkage

ACKNOWLEDGMENT

The authors acknowledge the LGP2 (Univ. Grenoble Alpes, CNRS, Agefpi) for the technical support.