Urea-formaldehyde resin and method of making same

Claim 1

IN THE PROCESS OF PREPARING A UREA-FORMALDEHYDE RESIN IN WHICH THERE IS REACTED A RATIO OF 1 MOLE OF UREA, TO 1.2 MOLES OF FORMALDEHYDE, THE STEPS COMPRISING ADMIXING WITH THE FORMALDEHYDE AN AMOUNT OF CAUSTIC SODA SOLUTION SUFFICIENT TO ADJUST THE PH OF THE FORMALDEHYDE TO BE WITHIN A RANGE OF FROM 9.20 TO 9.50; HEATING THE FORMALDEHYDE TO QUICKLY RAISE ITS TEMPERATURE SUBSTANTIALLY 150* F.; ADMIXING AT A RAPID RATE ACCOMPANIED WITH RAPID AGITATION, FROM 75% TO 85% BY WEIGHT OF THE TOTAL AMOUNT OF UREA THAT IS TO BE REACTED WITH THE FORMALDEHYDE; ADJUSTING THE PH OF THE MIXTURE OF UREA AND FORMALDEHYDE, AS SOON AS ALL THE ADDED UREA IS IN SOLUTION, TO BE WITHIN A RANGE OF 9.2 TO 9.5; BOILING THE MIXTURE OF UREA AND FORMALDEHYDE AT ATMOSPHERIC PRESSUR FOR A PERIOD OF TIME OF FROM 15 TO 60 MINUTES; QUICKLY ADMIXING WITH THE BOILING MIXTURE OF UREA AND FORMALDEHYDE AT THE END OF THE BOILING PERIOD AN AMOUNT OF PHOSPHORIC ACID SUFFICIENT TO ADJUST THE PH OF THE MIXTURE TO BE WITHIN A RANGE OF FROM 4.55 TO 4.75; CONTINUING THE BOILING WITH CONTINUING AGITATION FOR A PERIOD OF SUBSTANTIALLY 12 MINUTES; QUICKLY ADMIXING AT THE END OF THE 12 MINUTES PERIOD, WITH CONTINUING AGITATION, CAUSTIC SODA IN AN AMOUNT SUFFICIENT TO ADJUST THE PH OF THE MIXTURE OF THE UREA AND FORMALDEHYDE TO FROM 7.2 TO 7.8; QUICKLY COOLING THE MIXTURE OF UREA AND FORMALDEHYDE, WITH CONTINUING AGITATION, TO A TEMPERATURE OF SUBSTANTIALLY 190* F. AND THEREAFTER ADMIXING THE REMAINDER OF THE UREA WITH THE MIXTURE OF UREA AND FORMALDEHYDE, WHEREBY A RELATIVELY STABLE AQUEOUS RESIN SOLUTION IS PRODUCED.