Patent ID: 6710159
Filing Date: 2004-03-23
Classification: B29B,C08G

Abstract:
A process for producing polyamide or copolyamide freed from volatile constituents from a polyamide 6 or a copolyamide of polyamide 6 in a melt, comprising:introducing a polymer melt into first shell-and-tube heat exchanger at a temperature of 200 to 300Â° C.; evaporating monomers and dimers at a temperature in the shell-and-tube heat exchanger of 250 to 300Â° C.; removing the volatile constituents in a first separator connected downstream at a pressure of at most 300 mbar (300 hPa) and at a temperature in the first separator of 250 to 300Â° C.; introducing a gaseous entrainer into the degassed polymer in a molar ratio of entrainer to polymer of at least 1:1; dispersing the entrainer in the polymer melt with a static mixing element; introducing the mixture into a second shell-and-tube heat exchanger or a loop-type evaporator or a combination of a second shell-and-tube heat exchanger and loop-type evaporator, in each case with a second separator connected downstream; evaporating further volatile constituents at a temperature of 250 to 350Â° C.; removing the further volatile constituents in the second separator at a pressure of at most 300 mbar (300 hPa) and at a temperature in the second separator of 250 to 300Â° C.; and removing the degassed polymer melt from the second separator.