| 摘要 |
PURPOSE:To make it possible to strictly control the position and arrangement of an intermediate layer in an injection-molded product by a method wherein the inner surface of a large diameter sleeve and the outer surface of a small diameter sleeve respectively consist toward their tips of a cylindrical surface having a comparatively large diameter, a convergent tapered surface and a cylindrical surface having a comparatively small diameter and the circular tip face of the small diameter sleeve is positioned retreating from an orifice. CONSTITUTION:In the nozzle 1 concerned, the inner surface of a large diameter sleeve 3 and the outer surface of a small diameter sleeve 4 respectively consist toward their tips of a cylinder surface having a comparatively large diameter, a convergent tapered surface and a cylindrical surface having a comparatively small diameter and the tip of the small diameter sleeve 4, which is made to be a circular tip face 19, is positioned at a position retreated from an orifice 5 or the position, in which the tips of an intermediate layer resin passage 7 and of an inner layer resin passage 8 are substantially flush with the circular tip face 19. By the constitution as described above, since the straight cylindrical passage is connected through the convergent tapered passage to the intermediate layer resin passage 7, intermediate layer resin, the compressive force developed at the tapered passage of which is fully relieved by said straight cylindrical passage and, as a result, the resin is introduced in the form of laminar flow in the space at the rear of the orifice. |
