Thermoplastics waste melt reworking unmelted constituent - by extrusion feeding up to 50 per cent solids to rotatable changeover valve with decompression vent to alternately and continuously fill moulds

摘要

Size-reduced material is plasticised in a screw extruder and led through a flow channel to a flow divider from which it alternately and continuously fills moulds, from which the mouldings are removed after cooling. The flow divider comprises rotatable valve with filling channel connecting to mould and a pressure release channel leading from the other, previously-filled mould to a vent. ADVANTAGE - Economic and continuous, permits up to 50 wt.% solids and avoids overload and intermittent operation of the extruder. The decompression arrangement avoids back pressure from the filled mould during changeover. The process is tolerant to moisture content of the feed. The unplasticisable constituents can be used to increase the strength of the end prod. without further additives.