| abstract |
The present invention relates to a process for the manufacture of a solution of a salt of a diamine and of a diacid for the manufacture of polyamide. The invention relates more particularly to a process for the manufacture of a concentrated solution of hexamethylene diammonium adipate salt, also called nylon salt, used as starting material for the manufacture of polyamide, more specifically of PA66. The process for the manufacture of an aqueous solution of diamine and diacid salts obtained by mixing a diacid and a diamine, at a salt concentration by weight of between 50% and 80%, consists, in a first stage, in producing an aqueous solution of diacid and diamine having a diacid/diamine molar ratio of greater than 1.1 and, in a second stage, in adjusting the diacid/diamine molar ratio, by adding diamine, to a value of between 0.9 and 1.1, preferably between 0.99 and 1.01, and in fixing the salt concentration by weight by, optionally, adding water. |