Verfahren zur kontinuierlichen Herstellung synthetischer linearer Polymerisate

摘要

In an evaporation process, the liquid to be evaporated is introduced through inlet 55 into a frusto-conical chamber 44 wherein the liquid is distributed by rotating vanes 52 in the form of a film on the heated wall 43 of the chamber, the residual liquid being discharged through outlet 57. The vapours flow through the shaft 46 via ports 51, and are discharged through outlet 62. The liquid may be passed through a series of such evaporators.ALSO: In a process for the continuous preparation of synthetic linear polymers containing recurring carbonamide groups as an integral part of the main polymer chain separated by at least two carbon atoms, an aqueous solution of a material capable of undergoing polycondensation to form said polymer is evaporated to reduce the water content thereof, the residue of the evaporation is heated under pressure to convert said material into a polymer capable of undergoing further condensation into a higher molecular weight polymer with elimination of water of reaction, the pressure on the partially converted product is reduced and the molecular weight of the partially converted product is increased and water of reaction is expelled therefrom, the aqueous solution is continuously annulated in the form of a turbulent thin annular film by being centrifuged against the inner periphery of an annulus, continuously moving said film along the length of said annulus, and the film heated during its movement therealong to reduce the water content of the aqueous solution. In the example, an aqueous solution of hexamethylene adipamide is fed from the mix tanks 101 and 111 into the thin film evaporator 141 where it is subjected to heat and pressure, the resultant volatile products being removed, a titanium dioxide slurry added and the mass fed to a second film evaporator 221 where further volatile products are removed, then mass then being fed to the flasher 281 where the pressure is quickly reduced to atmospheric, the polymer being discharged via the final evaporator 351. The construction of the evaporators is described.