Method for producing urea formaldehyde core binder resins

Claim 1

A PROCESS FOR PRODUCING A WATER-CLEAR UREA FORMALDEHYDE CORE BINDER RESIN OF INCREASED TENSILE STRENGTH AND SHELF LIFE WHICH COMPRISES HEAT-MIXING 1 MOL OF SOLID UREA WITH 2.2 MOLS OF 37 PERCENT FORMALDEHYDE SOLUTION AT A PH OF BETWEEN 8.7 AND 9.2, SAID PH BEING OBTAINED BY ADDING TO THE UREA FORMALDEHYDE MIXTURE APPROXIMATELY 0.1 MOL OF AQUEOUS AMMONIA SOLUTION, HEATING SAID REACTANTS TO A TEMPERATURE IN THE NEIGHBORHOOD OF ABOUT 200-220*F., MAINTAINING SAID REACTANTS AT THE STATED TEMPERATURE DURING A REFLUX PERIOD OF ABOUT 17 TO 19 MINUTES, REMOVING FROM THE REACTION MIXTURE BY VACUUM DISTILLATION UNREACTED COMPONENTS OF THE REACTION MIXTURE AND WATER PRODUCED DURING THE REACTION, SAID DISTILLATION BEING CONTINUED UNTIL APPROXIMATELY 25 PERCENT BY WEIGHT OF THE ORIGINAL REACTANT MIXTURE HAS BEEN OBTAINED AS DISTILLATE, COOLING SAID REACTION MIXTURE AFTER DISTILLATION TO SUBSTANTIALLY ATMOSPHERIC TEMPERATURE AND STABILIZING SAID REACTION PRODUCT WITHIN A SHORT TIME AND BEFORE GELLATION OCCURS THEREAFTER TO A PH OF BETWEEN 7.5 AND 8 WITH A SOLUTION OF STABILIZER SELECTED FROM THE GROUP CONSISTING OF SODIUM PYROPHOSPHATE SODIUM PYROPHOSPHATE DECAHYDRATE AND SODIUM TRIPOLYPHOSPHATE.