JP2776450B

PURPOSE:To perform easily a material change and color change, improve productivity and drastically reduce consumption of resin, by a method wherein an inlet opening part communicating with a resin passage of a dwelling resin discharge hole is provided freely and movably with a plug having a gap between the same and the inside of its opening part. CONSTITUTION:At the time of molding of an ordinary blow molded product which performs neither a material change nor color change, molten resin continues a condition wherein the molten resin flows in gradually respectively toward dwelt resin coming out holes 55, 56 through an annular passage between an inner circmferential surface of inlet opening parts 50a, 51a within the advancing limit of a plug 43 and the outer circumferential surface of the plug 43 and the inflow resin is discharged outside through outlet opening parts 55a, 56a. On the one hand, in the case where it is desirous to replace the old resin left behind in the vicinity of an inlet opening part 22a of a resin inflow port following the material change and color change and close by a resin dwelt part with fresh resin, when a nut 45a is turned, the plug 43 of the tip of a valve stem 44 and moved up to the backward movement limit and the inlet opening parts 50a, 51a are released completely through which replacement can be performed.