Chemi-refiner mechanical pulping of flax shives: refining energy and fiber properties.

Oil-seed flax shive has been promoted as a raw material for low-end paper making because of its overall cost benefit over hardwood and groundwood pulp and increasing demand for low-cost pulp in rigid packaging applications. We have made refiner mechanical pulp from oil-seed shives by using a 300 mm Sprout-Bauer pilot refiner. The factors controlled during refining were: consistency, multi-pass refining, temperature, spacing between the plates and polyol-anhydride reactant concentration. Based on the results in this study it is apparent that unmodified shives develop low mechanical strength, shorter fibers and large amount of fines. Chemical modification of shives with a pre-reacted mixture of polyol-anhydride reduces refining energy consumption, improves strength performance but decreases scattering coefficient. From the results of investigation it is suggested that chemically modified refiner pulp from shives cannot be used for high-grade paper manufacture but it can be used as a low-cost filler for low-end applications in packaging or low-performance decorative papers.