Sand mold process using resinous binder from alkaline condensation of urea, formaldehyde, and furfuryl alcohol

Claim 1

A PROCESS FOR MAKING SAND MOLDS AND CORES COMPRISING THE STEPS OF ADMIXING AN ACID CATALYST AND RESINOUS CORE BINDER WITH A FOUNDRY SAND, SAID RESINOUS CORE BINDER BEING PRESENT IN AN AMOUNT OF FROM ABOUT 0.5% TO ABOUT 6% BY WEIGHT AND COMPRISING AN ALKALINE COPOLYMERIZATION PRODUCT OF A MIXTURE CONSISTING ESSENTIALLY OF FORMALDEHYDE, UREA, FURFURYL ALCOHOL, AND AN ALKALINE CARALYST IN THE PROPORTIONS OF GREATER THAN 2 AND UP TO ABOUT 4 MOLES FORMALDEHYDE AND FROM ABOUT 0.1 TO ABOUT 1.7 MOLES FURFURYL ALCOHOL PER MOLE UREA AND A SUFFICIENT QUANTITY OF SAID ALKALINE CATALYST TO MAINTAIN SAID RESINOUS CORE BINDER AT A PH OF FROM AT LEAST 7.0 TO ABOUT 9.0 PRIOR TO ADMIXTURE WITH SAID ACID CATALYST, SAID ACID CATALYST BEING PRESENT IN A QUANTITY SUFFICIENT TO REDUCE THE PH OF SAID RESINOUS CORE BINDER BELOW 7.0, CONTINUING SAID MIXING UNTIL A SUBSTANTIALLY UNIFORM MIXTURE IS OBTAINED, AND THEREAFTER APPLYING SAID MIXTURE TO A HEATED PATTERN FOR A PERIOD OF TIME SUFFICIENT TO INITIATE CURING OF SAID RESINOUS CORE BINDER.