Biuret-urea-formaldehyde resins

Abstract

Abstract A METHOD OF FORMING A BIURET-UREA-FORMALDEHYDE POLYMER AND THE PRODUCT THEREOF, INCLUDING, MIXING FORMALDEHYDE WITH THE BIURET, IN THE RATIO OF 0.8 TO 1.1 MOLES OF FORMALDEHYDE PER MOLE OF PRIMARY AMIDE GROUP IN THE BIURET AND THE HEREAFTERMENTIONED UREA, IN THE PRESENCE OF AN ACID, SUCH AS HYDROCHLORIC ACID, FORMIC ACID, ETC., IN AN AMOUNT SUFFICIENT TO ATTAIN A PH BETWEEN ABOUT 3.7 AND 4.8, AND MAINTAINING A TEMPERATURE BETWEEN ABOUT 70 AND 100*C. FOR A PREDETERMINED PERIOD OF TIME AND THEREAFTER ADDING THE UREA IN AN AMOUNT SUCH THAT THE RATIO OF BIURET TO UREA IS BETWEEN ABOUT 0.4 AND 9, ADJUSTING THE PH WITH AN ACID OR A BASE TO A VALUE OF ABOUT 3.7 TO 5.6 AND COOKING THE SOLUTION FOR A PREDETERMINED PERIOD OF TIME. THE EXOTHERMIC REACTION CAN BE MODERATED BY THE ADDITION OF A BUFFER, SUCH AS DISODIUMCYANURATE, SODIUM ACETATE, SODIUM BORATE, SODIUM PHOSPHATE, SODIUM CITRATE, ETC., IN AMOUNTS OF ABOUT 1 TO 12% BASED UPON THE VOLUME OF UREA AND BIURET. THE RESULTANT POLYMER MAY BE CURED BY THE ADDITION THERETO OF AN APPROPRIATE CATALYST, SUCH AS AMMONIUM CHLORIDE, AMMONIUM SULFATE, AMMONIUM PHOSPHATE, ETC., IN AMOUNTS OF ABOUT 1 TO 1.5% BY WEIGHT, BASED ON RESIN SOLIDS.

Inventors

• 👤 George O Orth Jr

Bibliographic Details