BigPatents India

An objective of the present invention is to provide a desolvation method for removing a solvent efficiently from a polymer solution. In the present desolvation method where the solvent is removed from the polymer solution by steam stripping using an apparatus comprising a pipe which connects gas phase portion of a desolvation tank at the downstream and a liquid phase portion of a desolvation tank at the upstream, and an opening degree adjusting mean (for example, pressure adjusting valve) fixed to this pipe, pressures are controlled such that a pressure difference (P=P2-P1) between pressures of each gas phase portion of desolvation tanks at the downstream and at the upstream is allowed to be larger by from 0.005 to 0.6 MPa, preferably from 0.05 to 0.3 MPa than a pressure difference when the opening-degree adjusting mean is fully opened. In addition, in another present invention, pressures are controlled such that the pressure difference between pressures of each gas phase portion of desolvation tanks at the downstream and at the upstream is allowed to be 0.036 MPa or larger, preferably 0.1 MPa or larger. (FIG. - 6)