Patent ID: 6306194
Filing Date: 2001-10-23
Classification: C05C,C05G

Abstract:
A method of producing a urea-formaldehyde resin comprising:1) combining formaldehyde, urea, and ammonia in a basic solution at a formaldehyde/urea/ammonia ratio of about 5.4-3.6/1/0.45-0.65;2) heating the solution to about 85 to about 95.degree. C., and holding to ensure triazone formation;3) cooling the solution to less than about 50.degree. C., and adjusting the pH to about 9.5 to about 10.5;4) adding sufficient urea and ammonia to the solution to change the ratios to about 1.1-0.6/1/0.11-0.08;5) reheating the solution to about 80.degree. C. to about reflux, at a pH of between about 9 and about 11, for about 1 to about 2.5 hours; and6) post charging urea to bring the mole ratio to about 0.9-0.6/1/0.1-0.08;wherein the nitrogen content of the resin is at least about 31% based on 100% resin solids.