P-RC alkaline peroxide mechanical pulping of hardwoods. Part 2 - Asian tropical hardwoods

A newly developed Alkaline Peroxide Mechanical Pulping (APMP) process, P-RC, and its applications with various Asian tropical hardwoods are presented. The process consists of mild thermal preconditioning of alkaline peroxide impregnated chips, and refiner chemical treatment (P-RC) to utilise the refining process for the desired chemical reactions. This new process is more flexible than the conventional APMP process, and develops better optical properties and improves chemical efficiency. Analysis of P-RC APMP pulps from eucalypts, acacia, albizia and mulberry, showed that they are comparable to most market hardwood BCTMP pulps in terms of handsheet strength and bulk properties. Among the wood species studied, Eucalyptus camaldulensis was found to have an intrinsically higher tensile/bulk ratio than E. globulus, which was similar to the other hardwood species studied. The P-RC process was compared with kraft pulping, and the results showed that P-RC pulp had a higher tensile at a given bulk, or a higher bulk at a given tensile. Potential applications of the P-RC pulps from the hardwoods studied were discussed in relation to market hardwood kraft and BCTMP pulps currently used in various paper and board grades.