Spinning of Regenerated Fibres from Paper Grade Pulp

The raw material base for the production of man-made cellulose fibres from wood is limited, as only highly processed dissolving pulps are used industrially. Technologies that enable the use of paper grade pulps as raw material for man-made textile fibres would broaden the raw material base and would enhance the use of wood biomass.

In this work, softwood and hardwood (eucalyptus) kraft pulps with high molecular weights and substantial amount of hemicelluloses were studied. Chemical and enzymatic pre-treatments were carried out to reduce the molecular weight of the pulps to pre-agreed level known to be suitable for good quality spinning dopes, and to produce pulps with different amounts of hemicellulose. The pretreated kraft pulps were dissolved in an experimental super-base ionic liquid, [mTBNH][AcO] and fibres were spun with a small-scale laboratory spinning unit with dry- jet wet spinning method.

Fibres were successfully spun from both hemicellulose containing kraft pulps after different pretreatments. The strongest regenerated fibres with >10 % elongation were spun from acid treated softwood kraft pulp. Hemicellulose content was not found to affect fibre strength, but fibre elongation was negatively correlated with hemicellulose content. The hemicellulose composition analysed form the regenerated fibres proved that hemicelluloses were, at least partially, regenerated to the textile fibres.

GRETE project will tackle the challenges caused by increased global demand for sustainable textile fibres by offering new breakthroughs in the wood-to-textile value chain. GRETE will improve the existing textile value chain through technological innovation by using a new raw material based on European paper grade pulps, implementing novel solvent systems based on ionic liquids, and feasible and sustainable modification procedures for cellulose dissolution and regeneration. This project has received funding from the Bio-based Industries Joint Undertaking (JU) under the European Union’s Horizon 2020 research and innovation programme.