Abstract: The present invention is directed to a continuous process for producing a foamable celluloid product by introducing a solid component (comprising nitrocellulose, chemical blowing agent (CBA), stabilizer and alcohol) and a liquid component (comprising camphor and acetone) into a mixer/devolatilizer machine where the chamber is under atmospheric pressure and having significant overhead space. The chamber is comprised of two zones wherein the first zone has a temperature that is less than the second zone and at least one rotor comprising hollow, temperature-controlled arms having a tilted angle affixed to the rotors. The rotors of the mixer/devolatilizer machine act to mix the solid and liquid components under lower shearing forces, lower mechanical stress and longer residence times than those used by twin-screw extruders.