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:
Feb. 10, 1998
Filed:
Feb. 23, 1996
Pravin K Kukkala, Raritan, NJ (US);
Andrew J Kielbania, Chalfont, PA (US);
Andrew P Full, Somerville, NJ (US);
Antonios Tontisakis, Englewood Cliffs, NJ (US);
National Starch and Chemical Investment Holding Corporation, Wilmington, DE (US);
Abstract
A process for preparing aqueous dispersions of polyurethanes comprises dispersing polyurethane prepolymer containing unreacted --NCO functionality in water with moderate agitation at a temperature at or below 65.degree. C., preferably at or below 38.degree. C., and more preferably within the range 38.degree.-25.degree. C.; simultaneously reducing the agitation to a mild rate and maintaining the temperature within the range 38.degree.-85.degree. C., preferably, 60.degree.-65.degree. C., until the reaction of --NCO with water levels off; adding an effective amount of a quenching agent to react with sufficient --NCO functionality to reduce the number of available --NCO groups that can react with water so that the evolution of CO.sub.2 is reduced or eliminated during storage of the polyurethane dispersion; and at any of the previous sequential steps adding an effective amount of a deaerating agent to reduce or eliminate CO.sub.2 foaming or to liberate any dissolved CO.sub.2 gas.