Patent ID: 9359477
Filing Date: 2016-06-07
CPC Classification: B01F,B01J,C08G,C08L

Claim Text:
1. A process for producing a polyamide, which process includes directly melt-polymerizing a diamine component including 70 mol % or more of p-xylylenediamine and a dicarboxylic acid component including 70 mol % or more of a C6 to C18 aliphatic dicarboxylic acid, in the absence of solvent in a batch-type reactor equipped with a stirring blade, the process being characterized by comprising: (1) reacting the diamine component with the dicarboxylic acid component under a pressure condition of 0.2 to 0.5 MPa (Abs); (2) maintaining a vapor phase section of a reaction tank of the reactor at 200° C. or higher during reaction by one or more steps selected from the group consisting of attaching a heater to a top plate of the reactor, controlling a reflux rate by controlling a temperature of a partial condenser on the reactor, and preventing heat dissipation at the top plate of the reactor; (3) stirring the contents of the reaction tank, from the start of adding the diamine component until after completion of the addition and before the start of pressure falling, such that the stirring-related Froude number represented by Fr=(N/60) (4) employing a stirring blade having no structural body in the horizontal direction or having a structural body in the horizontal direction, which body does not come into contact with the interface between the reaction mixture and the vapor phase section during stirring.