The brightness, bleachability and colour reversion of groundwood made of dry-stored wood and wood stored in accordance with the principles of climate adapted sprinkling were evaluated. Pulpwood stored for 0, 1 and 3 months was debarked, ground at atmospheric conditions and bleached by hydrogen peroxide. The effects of tannin damage and blue stain on these optical properties were also examined. Storage was negative with respect to brightness, especially wet storage with the high sprinkling intensity. After bleaching most of the brightness losses were regained with the exception of the high-intensity sprinkled wood. The high-intensity sprinkling also gave poorer brightness stability. Pulp made from blue stained wood suffered from decreased brightness compared with corresponding non-infected wood. The brightness was recovered after bleaching and blue stained wood did not affect brightness stability. Pulp made from tannin damaged wood suffered from decreased brightness, even after bleaching, and had lower brightness stability.
Persson, E; Bergquist, J; Elowson, T; Jäkärä, J; Lönnberg, B
Brightness, bleachability and colour reversion of groundwood made of wet- and dry-stored Norway spruce (Picea abies) pulpwood
Paperi Ja Puu-Paper And Timber