INJECTION MOLDING METHOD

摘要

PURPOSE: To facilitate the molding of a multilayered article by ejecting separate polymer materials individually by a multi-material co-ejection nozzle device to supply them to respective cavities. CONSTITUTION: A first polymer molten material is prepared in a flow passage 500 and prevented from passing through an orifice 502 to flow in a central passage 540 to allow a second molten flow of a separate material to flow in the central passage 540. During a period when the inflow of the first material to the orifice 502 is prevented, pressure is allowed to act on the second material in the flow passage 500 to make the pressure of the second material higher than the pressure of the central passage of the part surrounding the orifice of the first material flow at all of points surrounding the orifice 502 and the acting pressure is equalized over the whole periphery of an annular orifice. The pressurized first material is allowed to flow in the central passage 540 through the orifice. By this constitution, many kinds of molten flows are separately ejected and used in common by one ejection nozzle to easily mold a multilayered article.