The main raw material for rotomolding is one of the polyethylene resins, which is loaded into the mold to begin the process. In the heating chamber, the mold is rotated as it is heated. The frame of the mold is capable of rotating the mold to every point of its rotational axis. As the mold rotates, the resin is spread over the interior surface of the mold giving the finished product an equal and even thickness across its surface. http://www.rotomoldingchina.com/rotational-molds/