| abstract |
Lactams having 5-13 ring atoms are continously polymerized at atmospheric pressure in a vertical tube, the top portion of which contains a stirrer, the lactam in a molten state being added to the mixture of lactam and prepolymer at the top of the tube which is at the polymerization temperature. The top quarter of the tube may be 30-80% wider than the remainder and may contain a regulator for the lactam level and a heating coil. The remainder of the tube may contain a heat exchanger and a means for achieving uniform flow in the melt, e.g. a series of gratings. The lactam, e.g. e caprolactam may contain up to 15% water and other additives, e.g. pigments, catalysts, fillers, master batches and stabilizers. The polymerization temperature may be 240-280 DEG C. |