Improvements in and relating to solution polymerization

摘要

Unreacted monomer which is an ethylenically unsaturated hydrocarbon is recovered from a liquid solution of a polymer in an inert solvent, which has been obtained by solution polymerization, by vaporizing the monomer from a wiped-film of the solution while the film is swept by a counter-current flow of inert gas saturated with the inert solvent and separating the monomer from the resultant gaseous mixture. The hydrocarbons recovered, solutions and polymers specified are (1) a mixture of ethylene and propylene recovered from either an ethylene/propylene copolymer in n-heptane or an ethylene/propylene/11-ethyl-1,11-tridecadiene terpolymer in perchloroethylene; (2) 1,3-butadiene from cis-1,4-polybutadiene in benzene; (3) a mixture of ethylene and 1-butene from a terpolymer of ethylene/1-butene/dicyclopentadiene in cyclohexane; and (4) a mixture of ethylene, propylene and butene from a quaternarypolymer of ethylene / propylene/butene / 6-methyl - 1,5 - heptadiene in octane. The inert gas may be nitrogen. The hydrocarbon may be separated from the gaseous mixture by absorption in an inert solvent, e.g. the same as that of the solution of polymer, and then recovered by stripping the absorption liquor.ALSO: Unreacted monomer is recovered from a liquid solution of a polymer in an inert solvent, which has been obtained by solution polymerization, by vaporizing the monomer from a wiped-film of the solution while the film is swept by a counter current flow of inert gas saturated with the inert solvent and separating the monomer from the resultant gaseous mixture. The monomers recovered, solutions and polymers specified are (1) a mixture of ethylene and propylene recovered from either an ethylene/propylene copolymer in n-heptane or an ethylene/propylene - 11 - ethyl - 1,11tridecadiene terpolymer in perchloroethylene; (2) 1,3-butadiene from cis 1-4 polybutadiene in benzene; (3) a mixture of ethylene and 1-butene from a terpolymer of ethylene/1-butene/dicyclopentadiene in cyclohexane; and (4) a mixture of ethylene, propylene and butene from a quatropolymer of ethylene/propylene/butene/6 - methyl - 1,5 - heptadiene in octane. The inert gas may be nitrogen. The monomer may be separated from the gaseous mixture by absorption in an inert solvent, e.g. the same as that of the solution of polymer, and then recovered by stripping the absorption liquor. An apparatus is described (see schematic flow diagram).