Processing, thermoplastics feed hopper

New technology for reinforcing ABS with long fibres has been developed by Dow Plastics. It is described as Vitamins (because it can be introduced in the feed hopper of a plastics processing machine) and involves the use of a thermoplastic polyurethane as a compatibilizer between the glass and the ABS matrix (for it has good compatibility with both). 

Molding compound is transferred in the cold state by pressure from the material hopper into the main injection chamber. Here it can be preheated before injection into the heated mould tool. Injection, through a special nozzle, can be either by ram or screw pressure. If screw feed is used, the screw must be of the type designed to process thermosets as opposed to thermoplastics. 

The success of any continuous extrusion process depends not only upon uniform quality and conditioning of the raw materials but also upon the speed and continuity of the feed of additives or regrind along with the virgin resin (upstream). Actually, only thermoplastics go through extruders markets have not developed to date for extruded thermosets. Variations in the bulk density of materials can exist in the hopper, requiring controllers such... 

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