Method for devolatilizing polymer solutions

Claim 1

A method for removing volatile components from a polymer solution comprising at least 25 weight percent polymer, said method comprising: (A) uniformly feeding said solution of polymer through a zone of indirect heat exchange which comprises a plurality of channels, each having a substantially uniform surface to volume ratio in the range of about 4 to 50, height of about 0.05 to 0.5 inches, a width of about 1 to 4 inches, and a length of about 0.5 to 12 inches, wherein the polymer solution is heated in said channels to a temperature above the vaporization temperature of said volatile components and below the boiling point of the polymers within the solution, wherein a uniform pressure of about 2 atmospheres to about 200 atmospheres is applied to the polymer solution in each channel during heating, such that vaporization of the volatile components is substantially prevented while said solution is in the channels; (B) passing the solution from the heat exchange zone into a vaporization chamber at a pressure at which at least 25% of the volatile components of said polymer solution are vaporized upon exiting the zone of indirect heat exchange; and (C) recovering the devolatilized polymer solution.

Claim 2

A method for removing volatile components from a polymer solution comprising at least 25 weight percent polymer, said method comprising: (A) uniformly feeding said solution of polymer through a zone of indirect heat exchange which comprises a plurality of channels, each having a substantially uniform surface to volume ratio in the range of about 4 to 50, height of about 0.05 to 0.5 inches, a width of about 1 to 4 inches, and a length of about 0.5 to 12 inches, wherein the polymer solution is heated in said channels to a temperature above the vaporization temperature of said volatile components and below the boiling point of the polymers within the solution, wherein a uniform pressure of about 2 atmospheres to about 200 atmospheres is applied to the polymer solution in each channel during heating, such that vaporization of the volatile components is substantially prevented while said solution is in the channels; (B) passing the solution from the heat exchange zone into a vaporization chamber at a pressure at which at least 25% of the volatile components of said polymer solution are vaporized upon exiting the zone of indirect heat exchange; and (C) recovering the devolatilized polymer solution.