Viscose production : Impact from alkali resistance (R18) and hemicellulose content in dissolving cellulose on the processability and quality of viscose.

Abstract: In this study the influence of variations in alkali resistance (R18) of cellulose on the quality of the viscose product in terms of carbohydrate content have been examined. The dissolution pattern of hemicellulose in the first steps of the viscose process with different running parameters has been determined. Furthermore the correlation between R18 and hemicellulose content has been studied. Mercerization and pressing was performed in a viscose micro plant at MoRe Research with varying process settings using samples with different R18 and known carbohydrate content. The carbohydrate content was thereafter determined in both the deducted lye and in the alkali cellulose in order to study the dissolution pattern of hemicellulose. A comparison was made in terms of carbohydrate content between speciality celluloses with varying R18 for determining the correlation between the variables. The study showed a clear influence from R18 on the amount of hemicellulose continuing in the viscose process after the pressing. Variations in NaOHconcentration in the mercerization and the press factor in pressing have also a significant effect on the dissolution of hemicellulose while the temperature in mercerization did not have a distinguishable impact. Finally the study also indicated a linear relationship between R18 and the hemicellulose content in speciality cellulose from Domsjö Fabriker.