Coinjection of hollow articles and preforms

A coinjection molding apparatus for molding articles and preforms, said apparatus comprising:

• at least one mold cavity, said cavity having a nozzle including a nozzle gate individual thereto,
• a hot runner system including conduit means in said nozzle for supplying at least two thermoplastic materials to said nozzle gate, each material originating from a separate source and each material having a substantially different optimum processing temperature,
• said conduit means including a first nozzle channel providing a conduit to said gate for a first molding material, and a second nozzle channel providing a conduit to said gate for a second molding material,
• heating means individual to each channel for maintaining each said channel at said substantially different optimum temperature appropriate for molding material flowing through the respective channel, and
• insulating means in said nozzle separating said channels, said insulating means being substantially coextensive with said nozzle and with said first and second nozzle channels whereby the insulating means is operative to block heat transfer from one nozzle channel to the other so that the respective molding materials arrive at the nozzle gate at said optimum processing temperatures.