Nozzle for sandwich construction injection mouldings - elastic valve plate plus controls permit skin or core polymer flow

摘要

Injection moulding nozzle, for injecting at least two different polymers to produce composite (sandwich) mouldings, has a main bore plus at least two feed holes and a valve to combine/separate them. This valve has an elastic bored plate on the inlet side, polymer feed holes lead to a space on each side, at the back of the plate a through hole has a seal face. The plate is moved into two positions, in the first at least part of its front face seals off the inlet side of the main bore, in the second it is lifted away and allows connection between the inlet side space and the main bore. Arrangement permits very short injection times; bore size is unaffected by the valve design.