Method of injection molding a three-layered container

Abstract

A method for manufacturing a three-layered container by injection molding, the method consecutively including steps of: (a) preparing an injection molding apparatus having: an inner injector element having a tubular inner body and a flow path communicating with the inner inlet nozzle and an inner injection nozzle formed both ends of the body, respectively; and an outer injector element having a tubular outer body including an outer injection nozzle and an outer inlet nozzle, the outer injector element disposed to hold the inner injector element so that a tubular space is formed between the inner and the outer bodies, the inlet nozzle of the outer body communicating with a curved groove formed in the outer surface of the inner injector body; and the inner surface of the outer body and the outer surface of the inner body are in a form so that the thickness of the tubular space therebetween is smaller at a portion compared to other portions; (b) injecting a first resin from the outer injection nozzle; (c) injecting a second resin from the inner injection nozzle 0.0001-3.0 seconds after the end of the preceding step of injecting the first resin; and (d) injecting the first resin from the outer injection nozzle, 0.0001-1.0 second after the start of the precedent injecting the second resin.

Dependencies are inferred from the claim text.