Title
Processing and structure of paperboard with a needled middle layer
Authors
MARIA KLINGBERG ANTAL BOLDIZAR and KARIN HOFER

Received June 6, 2017
Published Volume 53 Issue 3-4 March-April
Keywords paperboard, wood cellulose fibre, needle punching, network structure, fibre orientation

Abstract
The possibility to change the fibre network structure of paperboard by using the needle punching method was studied. Needling was performed on the middle layer made from unbleached softwood kraft pulp at a dry content of 20%. The needled structure was studied by several microscopy methods, which showed that the fibres were redistributed mainly in-plane. Denser regions of the fibre network structure were observed close to the needle penetration sites. The local density was estimated to be 25% higher than that of the surrounding unaffected structure.