The potential of bagasse soda pulp as a strength enhancer for old corrugated pulp

Blending unbleached bagasse soda pulp with old corrugated container (OCC) pulp to reinforce the strength properties of the OCC is investigated. Firstly, bagasse pulp was collected from a local paper mill and the refining behaviour and strength development of this bagasse pulp was evaluated. The results demonstrated that application of up to 200 kW/h specific refining energy (SEL 0.5 J/m), improved the strength properties. This indicated that mild refining is helpful in strength development of this pulp and the open structure of bagasse fibres do not impose severe problems if low specific edge load is used. Bagasse pulps refined to different degrees were selected for blending with unrefined OCC pulp. The ratios of bagasse refined pulp was varied up to 20% of the fibre furnish. The results revealed that higher dosages of the bagasse refined pulp improved all properties of the OCC pulp except tear index. It is generally accepted that OCC pulp has lost bonding potential between the fibres and adding refined bagasse pulp improves the inter-fibre bonding between the OCC fibres.