Influence of pulp refining on tissue paper properties

We investigated the influence of refining conditions (refiner tackle type and specific edge load) on bulk softness, absorbency, tensile strength, and wet tensile strength of bleached pulp. Commercial elemental chlorine free (ECF) and totally chlorine free (TCF) bleached sulfite and kraft spruce, birch, and eucalypt pulps were used in this investigation. We found that refiner tackle type and specific edge load had a significant influence on the evaluated properties. Higher specific edge load when using a universal tackle increases softness and absorbency of hardwood kraft pulps. The highest tensile index of bleached hardwood kraft and spruce sulfite pulps was achieved by fibrillation refining at low specific edge load (under 0.70 J/m). The wet tensile strength index of the tested pulps beaten to 30 degrees SR increased 3-4 times. Pulp refining increases wet tensile index and reduces water absorbency of paper. Hardwood kraft pulps are suitable for production of tissue paper with high softness and absorbency. Spruce sulfite pulps are suitable to achieve high bulk softness and low tissue paper absorbency. Birch kraft pulp is a good choice if a higher tensile strength is required in addition to softness and absorbency. To manufacture tissue papers with deep embossing, softwood kraft pulp is required because of its high strength properties.