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:
Jun. 01, 1976
Filed:
Nov. 08, 1974
Baden McDowall Pinney, Kingston, CA;
Du Pont of Canada Limited, Montreal, CA;
Abstract
Improved control is provided in a process for the continuous preparation of a polyamide from an aqueous solution of polyamide-forming reactants, e.g., from an aqueous solution of hexamethylene diammonium adipate. The process comprises feeding continuously, the aqueous solution of polyamide-forming reactants or partially polymerized polyamide-forming reactants to an elongated tubular zone having an inlet pressure of at least 60 lb./sq. in. absolute; passing the solution through the elongated zone and gradually reducing the pressure along the zone to progressively flash water into steam while supplying sufficient heat to maintain the temperature of the solution above the melting point of the resultant polyamide; and passing the molten polyamide from the tubular zone into a finishing vessel. The improvement comprises maintaining a substantially constant level in the finishing vessel by controlling the pressure in the tubular zone and thus regulating the flow of molten polyamide from the tubular zone by injecting steam at an intermediate point in the tubular zone.