Process for making a wood-thermoplastic composite

摘要

The invention relates to a method for making a dimensionally stable wood-thermoplastic composite material composed of a wood component and a thermoplastic component comprising the steps of forming a wood-thermoplastic mass at a temperature above the melting temperature of the thermoplastic component. The mass is then passed through a converging die to form a shaped extrudate profile having a cross sectional shape wherein at least a part of the converging die is maintained at a substantially higher temperature than that of the mass. The profile is then fed through a low friction thermally insulating land section, the land section having the substantially the same cross sectional shape as the exit end of the converging die. The profile is then quenched in a non-oxidizing environment to form a substantially dimensionally stable outer shell around the profile, the shell having a temperature below the melting temperature of the thermoplastic component. The invention also relates to a die assembly for making a wood-thermoplastic composite material.