APPUCATION OF LIGNIN AS FILLER FOR THE MIDDLE LAYER OF CARTON BOARD

Abstract

Lignin is second most abundant renewable raw material available on earth. Despite of its unique characteristics as natural product most lignin obtained by pulping is burnt for its fuel value and only 2% separated lignin from wood biomass is used for other purposes. This ignores the fact that many modern kraft mills could get benefits from lignin recovery in terms of both product capacity and process economy. In the present study it was proposed that lignin particles as filler added in middle layer can improve specific volume and ultimately the bending stiffness. This can result in replacing some pulp amount with lignin particles and can help in product economy of carton board. Thus major goal of this project is to find suitability of lignin particles as filler for the middle layer of carton board. Results of laboratory forming symmetrical tn-layer carton board having lignin particles as filler in middle layer shows improved bending stiffness and drainage time at the cost of decreased Z Span strength and Short Compression Test (SCT) for both the pulp, i.e. mechanical and recycled. Results also shown that by adding lignin particles in middle layer having recycled pulp, costly mechanical pulp that gives a high specific volume can be replaced by recycled pulp with improved strength properties and bending stiffness.