Changes in the Morphological Characteristics of Secondary Fiber Obtained from Wet-Strength Paper during Gentle Refining of Recycled Pulp. Part 1. Fiber Characteristics

The efficient use of papermaking potential secondary fiber by gentle refining recycled pulp is one the basic principles for recovered paper stock preparation. mild modes more important in case wetstrength than conventional waste paper. This due to fact that weakened hard conditions wet-strength repulping, particular, long repulping time, elevated temperature, alkali and oxidizers. study aims at evaluating changes morphological characteristics during low-consistency pulp. analysis was carried out two complementary directions, i.e. fibers (part 1) fines 2). Recycled (RP) obtained from commercial tissue consisting 100 % bleached softwood kraft (BSKP) made pine (Pίnus sylvéstris L.). performed 60 °C three ways, namely, with sodium hydroxide (indicated as RP(NaOH)), persulfate (RP(NaOH + Na2S2O8)), finally potassium monopersulfate KHSO5)). Secondary well primary BSKP had similar length distribution before after refining. Mean first recycle reduced 5–6 %. calculated values fibershortening index showed cutting practically does not occur refiningof pulps. increase degree pulps mainly explained fibrillation fibers, rather formation a large amount fines. have high slenderness ratio ((L/W)l 66.3 66.5 (L/W)w 83.6 84.3; where L – length, W width) corresponding good potential. results accelerated leads straightening. overall shape factor achieved combination (by ~ %) 40 %).