NORDIC PULP & PAPER RESEARCH JOURNAL
Home » Volume 31, 2016 » Issue No. 4
PAPER PHYSICS
Effect of refining on strength efficiency in twin-wire roll forming of never-dried unbleached softwood kraft pulp
Bengt Nordström, SCA R&D Centre, Sundsvall, Sweden and Lennart Hermansson, Innventia AB, Stockholm, Sweden
Abstract
Whereas refining is required for the strength development of chemical pulps, it has been unclear how refining affects the utilization of the furnish strength, as reflected by the handsheet strength, in the machine-made paper (strength efficiency). This work examined effects of refining on formation and strength efficiency in twin-wire roll forming of never-dried unbleached softwood kraft pulp in a pilot machine investigation comprising three separate sections.
The first section showed that a change in refining energy has no significant effect on formation, tensile strength efficiency, tensile stiffness efficiency, or compression strength efficiency at a given consistency when the fiber length remains similar. The second section demonstrated that a change in kappa number has no significant effect on formation or tensile strength efficiency at a given consistency when the fiber length of the refined pulp remains similar. Here, an increase in kappa number involved an increase in refining energy. The third section showed that a reduction in headbox consistency results in an improvement in formation and tensile strength efficiency that is similar in magnitude over the whole refining curve.
Keywords
Compression strength, Consistency, Formation, Kappa number, Kraft pulps, Refining, Stiffness, Tensile properties, Tensile strength, Twin wire machines
Pages
624-633
DOI
10.3183/NPPRJ-2016-31-04-p624-633
Price
22 EUR (excl. VAT) Buy PDF
Nordic Pulp & Paper Research Journal (NPPRJ) is an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents, pulp and paper and including new fiber-based materials, recovery and by-products from pulping processes, bio-refining and energy issues. Articles meeting required scientific standards are accepted from any continent.
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ISSN: 0283-2631