| 摘要 |
1,154,104. Isolating elastomers. FARBENFABRIKEN BAYER A.G. 17 Feb., 1967 [31 March, 19661, No. 7691/67. Heading C3P. Elastomers are isolated from their solution in organic solvents by introducing said solution at the bottom end of a column through which is passed an aqueous medium effecting a fine distribution of said solution and separating at the head of the column aqueous medium, elastomer particles, steam, and azeotropically distilling organic solvent, in which procedure the temperature at the bottom end of the column is above the boiling point of said solvent or its azeotropic mixture and the temperature at the head of the column is below the temperature at the bottom of the column and is approximately equal to the boiling temperature of the azeotropic mixture. The solutions are those obtained at the end of polymerization and after inactivation of the catalyst. The solution is suitably introduced together with steam. Elastomers mentioned are homo- and copolymers of isoprene, butadiene, chlorobutadiene, and piperylene, rubbery ethylene copolymers, rubbery polyurethane prepolymers and silicone rubbers. The process may be carried out continuously and a flow sheet for such a process is,illustrated. In the example a solution of cis- 1 ,4-polyisoprene in benzene is obtained by polymerizing isoprene using a TiCl 4 /Al(C 2 H 5 ) 3 catalyst, inactivating the catalyst with methanol, and adding a phenolic stabilizer and stearic acid, and the elastomer isolated in accordance with the process described above. |
