| 摘要 |
PURPOSE:To improve the strength of a lens cover by unitedly, forming a single layer part and a multilayer part in the lens cover composed of resin with two or more colors. CONSTITUTION:While a rod valve 8 in a triple tubular injection nozzle is left at a prescribed position and after is moved backward, flow routes 5, 7 of transparent acrylic resin to compose an outer layer are opened and the transparent acrylic resin is injected. Continuously, when the rod valve 8 is moved further backward before the cavity of dies is not yet filled completely with the transparent acrylic resin, the flow route 6 of colored acrylic resin to compose an inner layer is opened and the colored acrylic resin is injected simultaneously with the transparent acrylic resin. Then, the rod valve 8 is moved forward and the flow route 6 of the colored acrylic resin is closed and the transparent acrylic resin flowing in the flow routes 5, 7 is continuously injected. When the rod valve 8 is moved further forward, all the routes are closed and injection process is finished. As a result, a lens cover with a multilayer structure with red color, orange color, transparency, etc., is obtained by one process and the strength is improved. |
