expanded or expansible plastic material for the production of foundry models lost and models lost of such a material

摘要

Expanded or expansible plastic material for the fabrication of sunk foundry models, comprised of an expanded or expansible polymer or copolymer generally used for the fabrication of such models, associated to an oxidant agent accepting the expansion operation without substantial alteration of its oxdizing properties, without substantially modifying the characteristics of the polymer or copolymer to which it is associated, before, during and after expansion, without affecting the cast metal quality, and having a decomposition temperature which is substantially similar to that of the polymer or copolymer to which it is associated in order to provide for the oxidation of the carbon and the hydrogen thereof during the casting of molten metal. Sunk model made of said expanded plastic material, and process for fabricating foundry parts by molding, implementing said sunk models.