FIELD: chemistry.
SUBSTANCE: invention relates to the process for the continuous production of polyamide 6 or copolyamides which are composed of at least 70 wt.% of repeating units ε-caprolactam as well as to a device for realising said method. Method for continuous production of polyamide 6 or copolyamides comprises provision of the starting reagents (a), formation of a prepolymer, and polycondensation of the prepolymer to form a main melt stream (b). Then, it comprises granulation of the polymer melt (c), extraction of the polyamide granulate (d) and drying (e). At that, the main melt stream (b) is taken from a subset and mixing the subset in a side stream in an extruder with a defined amount of an additive. Then the modified side stream is returned to the main melt stream (b) downstream before the granulation (c). Recycled and formed during the extraction (d) aqueous extract solution, that comprises ε-caprolactam, is concentrated and returned to the starting process (a). Apparatus for performing the method comprises at least one dosing unit (100a, 100b), at least one condensing device (110), at least one granulating device (120a, 120b, 120c), at least one extraction device (130a, 130b , 130c) and at least one drying unit (140a, 140b, 140c) which are located sequentially in the said order. Between at least one condensing device (110) and at least one granulating device (120a, 120b, 120c), an extruder (150) is arranged in a bypass (160), and at least one extraction device (130a, 130b, 130c) is connected to at least one evaporation device (170).
EFFECT: invention enables continuous modification of a polymer melt in a side stream, provides high degree of process flexibility and allows obtaining polyamide granulate of high quality.
16 cl, 3 dwg
