TMP long fibres as reinforcement pulp. Part 1. Laboratory tests

摘要

The average fibre length of TMP is much higher than GW and one might expect a reduced need of chemical reinforcement pulp when making LWC from softwood TMP. In practice, the difference is small. The interesting question is how to improve the reinforcement potential of TMP fibres.rnA long-fibre fraction was separated from highly refined mill TMP rejects for further treatment on a pilot scale. The studied treatments were refining and sulphonation followed by refining. Sheer refining did not affect single fibre stiffness whereas sulphonation reduced it substantially. Zero-span tensile strength was slightly improved by both treatments. Instead, single fibre strength derived from zero-span and fibre dimensions decreased somewhat.rnThe tensile index of the pulps, called MRP - mechanical reinforcement pulp and CMRP - chemimechanical reinforcement pulp increased by the treatments. Both treatments impaired tear index and fracture energy index but improved bonding. However, the strength level of chemical pulp was not reached with the exception of the tensile stiffness of CMRP. The fracture energy index was shown to depend on tensile strength, tensile stiffness and fibre length scaled by zero-span tensile strength. The low fibre strength is an essential reason for the poor reinforcement capability of (chemi)mechanical reinforcement fibres.