Device and method for synthesis of a polymer under separation of a gaseous substance

A continuous process for synthesizing a polymer with separation of a gaseous substance in an apparatus comprising

• a reaction space (1) having an upper section (11), a middle section (12), and a lower section (13),
• an inlet orifice (2) disposed in the middle section (12),
• a first outlet orifice (3) disposed in the lower section (13),
• a second outlet orifice (4) disposed in the upper section (11),
• a first return orifice (51) disposed in the lower section (13),
• a second return orifice (52) disposed beneath the upper section (11), where the first return orifice (51) and the second return orifice (52) are connected to one another by a return line (5) in which there is disposed a pump (53) set up to transport a liquid from the first return orifice (51) to the second return orifice (52),
• a distributing device (6) which delimits the middle section (12) from the upper section (11), and
• a removal device (7) disposed so as to be movable along the upper section (11), where the removal device (7) has a removal head (71) disposed on the inner wall at the top of the middle section (12) and where the removal head (71) makes contact with the inner wall at the top of the middle section (12) with deformation of the edges of the removal head (71), where
• the inlet orifice (2) is connected by means of an inlet line (21) to a wall of the upper section (11), the removal head (71) having an orifice (711) through which the inlet line (21) is conducted,
• comprising the following process steps:
• a) feeding a prepolymer melt (8) into a middle section (12) of a reaction space (1) through an inlet orifice (2),
• b) transporting a portion of the prepolymer melt (8) from a lower section (13) of the reaction space (1) disposed below the middle section (12) into an upper section (11) of the reaction space above the middle section (12) and distributing the prepolymer melt (8) over the inner wall of the middle section (12) by means of a distributing device (6),
• c) polymerizing the prepolymer melt (8) to give a polymer melt,
• d) removing the polymer melt from the reaction space (1) through a first outlet orifice (3) of the reaction space (1), and
• e) removing a gaseous substance (9) from the reaction space (1) through a second outlet orifice (4) in the upper section (11),
• wherein deposits on at least one inner wall of the upper section (11) are removed by a removal device (7), and
• wherein the polymer is a semiaromatic polyamide comprising at least one repeat unit having an aromatic group and at least one repeat unit having an aliphatic or cycloaliphatic group in incorporated form.