U.S. patent application 20190168432 (assignee Roctool, Le Bourget-du-Lac, France):
"A mold, particularly for injection molding, includes a shell defining a cavity delimiting a molding surface, a heat accumulator and inductor heater, configured to heat the heat accumulator. A receiving surface, which is a part of a surface of the shell other than the molding surface, is either exposed to or shielded from the heat of heat accumulator, to bring the entire molding surface to a predetermined temperature to inject the material into the cavity. ... [The] heat accumulator comprises a phase change material. This embodiment makes it possible to store thermal energy in the latent phase change heat of said material."