Continuous preparation of copolyamides from caprolactam and salt of diamine and dicarboxylic acid

US5039786A · kind A · utility

Assignee

• BASF SE

Inventors

• Gunter Pipper · Bad Dürkheim, DE
• Claus Cordes
• Franz Schmidt · Mannheim, DE
• Horst Reimann · Worms, DE
• Eckhard M. Koch

Key dates

• Filing date: Mar 29, 1990
• Grant date: Aug 13, 1991
• Expiry date: Mar 29, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G69/36
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Copolyamides are prepared by a continuous process in which PA0 (a) an aqueous solution of salts of equimolar amounts of diamines and dicarboxylic acids is passed, under superatmospheric pressure and with simultaneous evaporation of water, through a tubular precondensation zone with formation of a vapor phase and a prepolymer at above the melting point of the prepolymer, PA0 (b) the vapor phase is separated from the prepolymer melt, PA0 (c) the vapor phase is separated in a column into steam and an aqueous diamine solution, and the aqueous solution containing diamines is recycled to the polymerization, PA0 (d) the prepolymer melt is mixed with molten caprolactam at polyamide-forming temperatures, and PA0 (e) the mixture of prepolymer and caprolactam is passed downward through a vertical polymerization tube at polyamide-forming temperatures and a copolyamide is obtained.