Free-Close Molding Versus Molding to Stops in Wood-Resin Blend Processing

摘要

The influence of the manner and degree of compression on some physical and mechanical properties of molded wood-resin blends was studied. Yellow birch (Betula alleghaniensis) and Douglas-fir (Pseudotsuga menziesii var. menziesii) particles, processed from .015inch by 1-inch flakes, were used. The properties evaluated were modulus of rupture, modulus of elasticity, dimensional stability, water absorption, and flow. Flow was considered to be the ability of a blend to move in directions at right angles to an applied force. A method for evaluating such flow is described. Toward the upper limit of the compressive range, the degree of compression is more important than the manner (rate) of compression. Along with resin content, the degree of compression controls the formation of glue bonds which, in turn, control the properties of the molded product. The primary importance of species and particle size is in the influence of these variables on effective mat compression. (Author)