초록 ▼

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 aspec

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 a timing device. The timing device may also control the rate of the dispensing an individual material from each of the metering pots.

대표청구항 ▼

A method of injection molding multiple layer multiple material plastic preforms to be blow molded into biaxially oriented containers, said method comprising the steps of providing a multiple passage coxial nozzle and supply means for separately supplying different materials to selective ones of said

A method of injection molding multiple layer multiple material plastic preforms to be blow molded into biaxially oriented containers, said method comprising the steps of providing a multiple passage coxial nozzle and supply means for separately supplying different materials to selective ones of said nozzle passages, said method including the step of utilizing said nozzle and said supply means to separately and simultaneously inject the several plastic materials into an injection mold for a container preform, said nozzle being provided with a central passage and at least one surrounding passage converging on said central passage, a primary material is injected through one of said passages, and a secondary material being simultaneously injected through the other of said passages during a portion of the time said first material is being injected wherein said second material forms an intermediate layer between two layers of said primary material in a selected portion of said preform, said two layers of said primary material being directed through said central passage and said secondary material being directed through said surrounding passage to form said intermediate layer positioned off center in said preform towards an exterior of said preform.