The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 2000
Filed:
Jan. 30, 1998
David Neil Marks, Newark, DE (US);
Samuel Livingston Lane, Beaumont, TX (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
An improved method for manufacturing poly(hexamethylene adipamide), i.e. nylon 6,6, by reacting monomethyl adipate with hexamethylenediamine in an approximately equimolar ratio in the presence of water at a temperature of 100 to 165.degree. C. while simultaneous distilling off of a stoichiometric amount of methanol. The resulting aqueous intermediate product is then heated to 200 to 260.degree. C. while distilling off substantially all water at a pressure of 150 to 250 psig (1.03 .times.10.sup.6 to 1.72 .times.10.sup.6 Pa) followed by reducing the pressure to atmospheric pressure and increasing the temperature to 270 to 280.degree. C. to polycondense the distillate residue. Such a process is useful in producing high purity commercial grade poly(hexamethylene adipamide) that advantageously avoids problems caused by N-methylation of the polyamide.