SUGAR BEET PULP FIBROUS RESIDUES AS BONDING AGENTS IN PAPERMAKING

Fibrous residues from acid and enzymatic hydrolysis of sugar beet pulp can be applied to increase bonding potential and partial replacement of recovered fibres. The authors investigated the influence of original, chemically and enzymatically modified sugar beet pulp on fibre suspension and paper properties from recovered fibres. With increasing content of sugar beet pulp in a mixture with recovered fibres, drainage time and water retention Value increased, weighted average fibre length decreased, tensile and burst index, internal bond strength increased, bending resistance and porosity decreased. The effect of sugar beet pulo oil fibre suspension and paper properties increased in the sequence original, chemically and enzymatically modified sugar beet pulp. Optimum input of original sugar beet pulp is 15-20%, of chemically modified sugar beet pulp 10-15% and of enzymatically modified sugar beet pulp 5-10%. Addition of sugar beet pulp to recovered fibres had a similar effect on fibre suspension and paper properties as beating of recovered fibres. However, an increase of internal bonding strength is in comparison with beating of recovered fibres disadvantageous with regard to drainage time, water retention value and porosity. This disadvantage can be eliminated by applying a three-component retention and drainage system. The retention and drainage system improved drainage, reduced COD and BOD5 of filtrates from a mixture of recovered fibres with addition of sugar beet pulp and increased internal bond strength of paper. By applying a retention and drainage system, it is possible to increase optimal input of original, chemically and enzymatically modified sugar beet pulp in a mixture with recovered fibres approximately by 5%.