| 摘要 |
PURPOSE: To obtain synthetic resin board with grain pattern, which has no weak point on strength due to weldline to the width direction of the board and the strength distribution of which is uniform as a whole and which is excellent in thermoformability. CONSTITUTION: In an extrusion and development molding, in which tube body extrusion-molded in tubular shape is cut open at one place in a peripheral direction and developed so as to obtain flat board-like synthetic resin board material with grain pattern, a torpedo 7 or mandrel is suspended at one point or by cantilever fashion through a spider part 5, which is provided only at one place in a peripheral direction, as a circular die 2 used for extruding resin material. By cutting open the weldline part of resin formed by the spider part 5 and developing the tube body, the board is formed. |
