Spruce Woodmeal for Newsprint Applications: A Handsheet Study

This study shows that spruce woodmeal can be an alternative cellulosic-based wood additive for newsprint applications. This study used unbleached wood flour produced from Spruce sawdust, ground and sieved to a particle size of 20-40 µm, 40-70 µm, 70-120 µm and 200-500 µm.

Woodmeal was added at levels of 2%, 4%, 6%, 8% and 10% based on oven dry fiber content. The basis weight of the newsprint handsheet manufactured was 80 g/m². The study revealed the following outcomes:

Woodmeal with a particle size distribution of 20-40 µm had the highest density followed by woodmeal with 70–150 µm, 40-70 µm, and 200-500µm. Increasing the woodmeal amount resulted in higher porosity. Woodmeal with a particle size distribution of 20-40 µm gave the lowest porosity and a particle size of 40-70 µm gave the highest porosity.

The Tensile index and burst index show decreasing values for the addition of all woodmeals and particle sizes. Woodmeal with strength additive and a particle size of 20 – 40 µm outperforms the other woodmeal types at additions of 2%, 4%, 6% and 8%. For woodmeal with a particle size of 70–150 µm at an addition of 2% and 4% an increased and similar burst index resulted for the handsheets.

First pass retention and ash retention increased for all wood flours with a maximum at 92% and 81% respectively for the wood flour with a particle size of 40-70 µm.