| 摘要 |
PURPOSE:To prevent a sink mark from occurring by improving adhesion be tween a metallic insert and a resin layer by a method wherein the metallic insert is coated with polypropylene resin, and further they are coated with polyvinyl chloride resin. CONSTITUTION:A metallic insert is preliminarily held in a cavity of a mold by an insert pin or the like, and a sandwich injection molding method is applied thereto. That is, a specific amount of polyvinyl chloride resin being a front layer is injected in a first process and a polypropylene resin being an inner layer is injected from another injection mechanism in a second process. The inner layer is formed while the polyvinyl chloride resin injected in the first process is being extended on an inner face of the cavity. Lastly, the polyvinyl chloride resin composing an outer layer is injected again to form a sandwich structure in the mold. Thus, a composite having a structure wherein the metallic insert is a core material, and the polypropylene resin layer is of a sandwich form with a polyvinyl chloride resin layer, can be obtained. |
