| 摘要 |
PURPOSE:To prevent heat decomposable resin from adhering to stay over the mold surface and heat-decomposing, by a method wherein the periphery of the decomposable resin is wrapped with good heat-stable resin in the state that the heat-decomposable resin contacts neither with the mold surface at all nor with the mold surface excluding very small portions and, after that, said resins are co-extruded. CONSTITUTION:For the co-extrusion method, in case of the molding of a sheet, multi-manifold dies or a device consisting of a feed block connected with normal T-dies can be employed. In addition, in case of the molding of a pipe or a strand, a multi-layer pipe die for co-extrusion can be used for the molding. In case of the molding of the strand, a multi-layer die is used under the state that the core of the pipe die is removed. Polyolefin such as polyethylene, polypropylene, or the like, styrene resin such as polystyrene, ABS (acrylonitrile- butadiene-styrene terpolymer) or the like, acrylic resin such as polymethyl methacrylate, polyethyl methacrylate or the like, polycarbonate resin or the like is employed as the good heat-stable resin. |
