POLYAMIDE SYNTHESIS BY ESTER AMINOLYSIS .1. A NEW ROUTE FOR NYLON-6,6SYNTHESIS

A new route for nylon-6,6 synthesis has been studied. The process is g rounded on the synthesis of an alpha-amino omega-ester monoamide precu rsor (AME-6,6) easily available in reacting in the bulk hexamethylene diamine and dimethyl adipate at a low temperature (T approximate to 50 degrees C) preferably in the presence of a phenol derivative. In such conditions AME-6,6 precipitates with a very good yield (90-95%). One of the greatest advantages of AME-6,6 is to keep the stoichiometric ba lance for further polyamidation; that is not the case in other process es. Moreover AME-6,6 is very stable, e.g., even stored at room tempera ture under air during 50 days. Polyamides-6,6 have been obtained from AME-6,6 (used freshly prepared or after storage) in glass laboratory r eactors by direct heating under vacuum (T = 270 degrees C) with number -average molecular weights of roughly 20,000. (C) 1996 John Wiley & So ns, Inc.