Methods for removing volatile components from polymer solutions

A two-stage process for removing volatile components from a polymer solution having a polymer content >60% by weight, said process comprising:

• (a)
• (i) heating, in a first stage, the polymer solution in an indirect heat exchanger, which comprises channels, to a temperature of 150 to 400° C. at a pressure of 1.5 to 50 bar, and
• (ii) depressurizing subsequently, the polymer solution in the channels of said indirect heat exchanger to a pressure of 3 to 200 mbar, thereby causing the flow in the channels to become two-phase at least in part, and the volatile components to be partially separated from the polymer;
• and
• (b) freeing, in a second stage apparatus, residual volatile components from the polymer of said first stage at a pressure of 0.1 to 10 mbar and at a temperature of 200 to 450° C.,
• wherein the surfaces of said indirect heat exchanger and the surfaces of said second stage apparatus,
• that come into contact with at least one of
• the polymer solution,
• the polymer, and
• the volatile components,
• each consist of a material which contains less than 10% by weight iron.