Apparatus for the continuous demonomerization and postcondensation of Polyamide 6

Claim 1

A reactor for carrying out demonomerization and postpolymerization having a cylindrical wall with a horizontal axis, and which has a top and a bottom portion in which polymer melt can be placed, an interior rotor in the form of a cage arranged concentrically around said reactor axis and rotatably movable around said axis, said cage having around its periphery ring-shaped elements which are capable of partly dipping into melt which is placed in said reactor; said ring-shaped elements being inclined toward a plane perpendicular to the reactor axis wherein the inclination differs from the inclination of each adjacent element by a fixed angle, said ring-shaped elements thereby forming a screw-line, said ring-shaped elements being capable of propelling melt through the reactor at a desired speed proportional to said angle; said reactor also having weirs fixed at the bottom portion of the cylinder and located between said ring-shaped elements, said weirs being capable of preventing melt from flowing straight along the bottom of the reactor without being raised above the surface of the melt by the ring-shaped elements; said reactor thereby providing means for simultaneously removing volatiles, mixing polymer melt and controlling and achieving substantially uniform retention time for said melt in the reactor.