METHOD OF EXTRACTING POLYMER FROM SOLUTION Russian patent published in 2012 - IPC C08F6/12 C08J11/08 C08J3/14 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of extracting a polymer by injecting steam into a solution of that polymer, as well as a method of recycling the polymer. The method of extracting a polymer by injecting steam into a solution of that polymer includes a polar aprotic organic solvent (PAOS) which forms an azeotropic mixture with water, and a nonpolar organic compound which is miscible with the PAOS and immiscible with water and which acts as a phase separation agent (PSA), whose boiling point is below that of the water/PAOS azeotropic mixture, the amount of the injected steam being sufficient to give rise to the partial removal of the PSA via stripping and partial removal of the PAOS via azeotropic distillation, and the total amount of water being sufficient to give rise to precipitation of the polymer. The polymer solution also contains a C₂-C₆ linear aliphatic alcohol, at least during polymer precipitation. The polymer is selected from polymers derived from vinyl chloride or homopolymers (polyvinyl chloride PVC) or copolymers. The method of recycling the polymer involves the following steps: dissolving the polymer in a liquid medium comprising a PAOS, a PSA and a C₂-C₆ linear aliphatic alcohol; extracting the polymer using a process according to any one of the preceding claims; condensing vapour from this process in order to obtain a liquid; settling of the liquid so as to obtain an organic phase comprising the PSA, the main fraction of the PAOS and alcohol and a minor fraction of water, and an aqueous fraction comprising the main fraction of water and minor fractions of PAOS and alcohol; and, optionally, repeating the preceding steps in a loop using at least one part of the organic phase as the dissolving liquid medium, wherein recycling of the polymer takes place during dissolution/precipitation.

EFFECT: extracting a polymer without agglomeration of the polymer particles.

12 cl, 4 dwg, 2 ex