摘要 |
Thermoplastic resin is converted to void free billets and preforms, by techniques including: compaction of heated thermoplastic powders: compactionof heated extruded strands: rolling of heated ingots of plastic: simultaneous extrusion and combining of two or more groups of strands: coextrusion of two or more resin formulations: sequential compaction of dual powders: extrusion with differentially heated dies. The billets may be non-homogeneous in response to dielectric heating, to produce controlled temperature zones within the heated polymers, when used as billets and preforms.
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