Process for producing polyamide

• Main Authors: Shinohara, Katsumi, Kurose, Hideyuki, Kanda, Tomomichi, Kikuchi, Minoru
• Format: Patent
• Language: English; French; German
• Published: 11.07.2018
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

A process for producing a polyamide through direct polycondensation of a diamine component, which contains at least 70 mol% of a xylylenediamine containing at least 20 mol% of paraxylylenediamine, and a dicarboxylic acid component, substantially in the absence of a solvent and using a batch reactor equipped with a partial condenser; the process comprising the following steps: (1) a step of feeding the dicarboxylic acid component into the reactor, and then pressurizing the reactor to increase the inner pressure to a pressure of at least 0.1 MPaG, (2) a step of continuously or intermittently adding the diamine component to the dicarboxylic acid component while the pressure inside the reactor is kept at 0.1 MPaG or more and while the reaction system is kept in a uniform flow state as a whole, (3) after the addition of the diamine component, a step of lowering the pressure inside the reactor to atmospheric pressure or less at a pressure-lowering speed of from 0. to 1.0 MPa/hr.