PRODUCTION METHOD FOR POLYAMIDE

摘要

The present invention provides a production method for polyamides, whereby adherance of matter to a reaction tank gas phase section and a vapor tube is suppressed and little mixing in of unmelted matter caused by said adhered matter occurs in the obtained product, and in which: a diamine component including at least 70 mol pcnt paraxylene diamine and a dicarboxylic acid component including at least 70 mol pcnt C6-18 aliphatic dicarboxylic acid are directly melt-polymerized in the absence of a solvent, in a batch-type reaction device comprising agitation blades; (1) the diamine component and the dicarboxylic acid component are reacted under pressure conditions of 0.2-0.5 MPa (Abs); (2) the gas phase section temperature inside the reaction tank during the reaction is held at 200�C or higher; (3) inside the reaction tank is agitated such that the agitation Froude number indicated by a specific formula is 0.0002-0.15, from the start of the addition of the diamine component until after the completion thereof and before pressure reduction starts; and (4) agitation blades are used that do not have a structural body in the horizontal direction, or have a structural body in the horizontal direction that does not come in contact with the reaction fluid or the boundary of the gas phase section during agitation.