Strength improvement of linerboard by wet-end application of black liquor

초록

Effects of the wet-end addition of black liquor on strength properties of linerboard were investigated. Handsheets were prepared with old corrugated container (OCC) stock received from a linerboard mill and 20% of kraft black liquor based on dry pulp weight was added to the OCC stock. pH of the OCC stock was varied with alum and cationic Polyacrylamides with two different molecular weights were added as flocculants. Strength properties of OCC handsheets were noticeably improved by addition of black liquor while variations in formation and bulk of handseets were hardly noticeable. Strength properties can be further improved by addition of alum and a polymer floccuant. Especially, remarkable increase in folding endurance of handsheet from OCC stock was achieved with addition of black liquor, alum, and a high molecular weight flocculant. However, it seems that excessive aggregation of black liquor solids could hinder improvements of strength properties.

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