Internal gas pressure process for the production of plastic parts

The invention relates to a process for producing a molded part, wherein a molten polymer is introduced into a mold cavity of a mold and liquid carbon dioxide at a pressure of at least 150 bar, preferably at a pressure of at least 200 bar or bar is fed to at least 250 the mold cavity, whereby the polymer pressed against the walls of the mold cavity and a cavity is formed in the polymer.