METHOD FOR THE REMOVAL AND RECOVERY OF LACTIDE FROM POLYLACTIDE

摘要

The invention relates to a method for the removal of lactide from polylactide and recovery of lactide from a lactide-containing gas by cooling the hot lactide-containing gas, wherein a polymer melt travelling through a nozzle forms thin threads, the surface area of which is so large that in a normal-pressure or vacuum evaporator the lactide evaporates from the polymer rapidly into a hot carrier-gas flow and the polymer settles under gravity onto a collecting device. A hot lactide-containing gas is cooled rapidly to a temperature below 100 DEG C, whereupon the lactide crystallizes from gas, forming lactide crystals, which are separated from the gas.