硬材的某些因子对硬质纤维板性质的影响

本文论述以正常径级硬材生材、贮存材、含水率低的硬材木片、以及小径级硬材生材为原料制造纤维板的研究。研究结果表明,硬材贮存期在一年之内,对纤维板的强度性质没有显著影响,但降低了纤维板的耐水性。原料含水率低,浆料中的粗纤维含量增大,纤维板强度性质降低。纤维得率随着原料中的小径材的比例增大而降低,但纤维板的性能稍有提高。

SOME FACTORS OF HARDWOOD AFFECTING THE HARDBOARD PROPERTIES

Different raw materials for making hardboards were studied in a pilot plant scale, fresh, stored and dried hardwood chips and mixtures of fresh hardwood chips with chips of small size hardwood trees. Fresh hardwood chips were the basic reference raw material. The same defibrating conditions were used.Storage time less than one year had no significant effect on the mechanical board properties, but the water absorption and thickness swelling were increased significantly.Chips which were dried up to 90% dry content caused a somewhat coarser pulp than fresh chips of about 50% dry content. The mechanical board properties were somewhat reduced with increasing dry content. The effect on water absorption and thickness swelling could not be established.Chips of small size hardwood trees decreased the pulp yield and gave pulps with lower drainage time. Both the mechanical and water resistance board proptertise seemed to be improved with increasing amount of chips from small size hardwood.Chips of small size hardwood trees can thus be used in mixtures of up to 25 or perhaps 50% without any marked negative effects.