METHOD AND APPARATUS FOR INJECTION MOLDING OF MULTILAYER PREFORMS

摘要

A method of and apparatus for forming multiple layer preforms wherein the various layers may be varied as to number, material, thickness and position in the preform by controlling the injection of the specific materials as to timing, quantity and rate of delivery. Most specifically, a featured aspect is the ability to simultaneously deliver to an injection nozzle and through such injection nozzle into a preform mold cavity two or more molten plastic materials simultaneously. This is possible by way of a multiple gate nozzle and a plurality of separately operable metering pots all controlled by way of timing device. The timing device may also control the rate of the dispensing an individual material from each of the metering pots.