Effect of fiber length on formation and strength efficiency in twin-wire roll forming OPEN ACCESS
Bengt Nordström and Lennart Hermansson
A change in fiber length is known to change fiber flocculation and formation of machine-made paper, but it has been unclear how a change in formation through fiber length affects strength efficiency. (The strength efficiency reflects how well the furnish strength, as indicated by the handsheet strength, is utilized in the machine-made paper.) The effect of fiber length on strength efficiency in twin-wire roll forming was presently investigated by examining two furnishes with different average fiber length, prepared from the same batch of softwood kraft pulp, over a wide range of headbox consistencies on a pilot machine.
An increase in fiber length resulted not only in worse Ambertec formation over the whole range of headbox consistencies but also in faster relative deterioration of the formation with increasing consistency. Tensile strength efficiency and Z-strength efficiency were both reduced when the formation was impaired through increased fiber length, and the effect was similar to the effect of a corresponding change in formation through headbox consistency. A given change in formation, through fiber length or headbox consistency, had a larger relative effect on Z-strength efficiency than on tensile strength efficiency.
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. ISSN: 0283-2631