Patent ID: 7972544

Claim:
A resin multilayer injection molding method, comprising: using an injection unit for injecting and charging at least two kinds of resin molding materials in a cavity and a mold clamping unit for opening and closing a mold and performing mold clamping using a toggle mechanism, injecting and charging a first layer resin molding material in the cavity, and then molding; moving backward a movable platen to reach a given movable platen position (S 0 ) by mold opening to enlarge the cavity capacity to form a second cavity between the first layer resin molding material and the cavity surface; and injecting and charging a second resin molding material in the formed second cavity to obtain a multilayer molded article, wherein the movable platen is moved backward to a given movable platen position (S 1 ) so as to enlarge the second cavity capacity while the second layer resin is being charged, and, after the completion of the charging of the resin, the toggle mechanism is promptly driven to reduce the second cavity capacity by moving the movable platen to a given movable platen position (S 2 ), and after the lapse of a given time, the toggle mechanism is driven again to enlarge the second cavity capacity by moving the movable platen to a given movable platen position (S 3 ), enlarging the resin molding materials.