Dry blending and fusion of reground thermoplastics - and wood-based particles, to produce cheap granules for reprocessing by moulding or extrusion

摘要

A composite moulding material comprises a blend of chopped wood particles and reground thermoplastic material contg. 40-80% wt. of the wood-based material, where the particles have a mean length of 5-7mm and none has a section greater than 1 sq.mm. The particles are blended and bound by fusion of the thermoplastic constituents. The components are dry belded cold under shear conditions which fuse the thermoplastic constituents without involving external heating, pref. using a screw extrusion blender opt. fitted with a face cutting die to produce composite granules. Additives such as colourants, stabilisers, fire-retardants may also be added during blending. For re-use of sawdust, chopped savings, chopped packaging films etc., to produce a composite granulate suitable for injection moulding, extrusion, milling, thermoforming etc.