Method of making a dihydrate and anhydrous mixture of dicalcium orthophosphate dentifrice abrasive

Claim 1

A PROCESS OF MANUFACTURING A DICALCIUM ORTHOPHOSPHATE DENTIFRICE ABRASIVE WHICH PROCESS COMPRISES REACTING TOGETHER IN AN AQUEOUS MEDIUM HAVING A TEMPERATURE BELOW ABOUT 40*C. ORTHOPHOSPHORIC ACID AND LIME TO FORM REACTION MIXTURES IN THE FORM OF AN AQUEOUS SLURRY CONSISTING ESSENTIALLY OF LIME, ORTHOPHOSPHORIC ACID AND WATER, INCREASING THE TEMPERATURE OF SAID SLURRY TO ABOVE ABOUT 40*C. AFTER FROM ABOUT 80 TO ABOUT 98 WEIGHT PERCENT OF SAID ORTHOPHOSPHORIC ACID HAS BEEN CONVERTED TO DICALCIUM ORTHOPHOSPHATE DIHYDRATE AND THEREAFTER MAINTAINING THE TEMPERATURE OF SAID SLURRY ABOVE ABOUT 40*C. UNTIL THE REMAINDER OF SAID ORTHOPHOSPHORIC ACID HAS REACTED WITH LIME TO THEREBY FORM PRECIPITATED ANHYDROUS DICALCIUM ORTHOPHOSPHATE; THE RESULTING DICALCIUM ORTHOPHOSPHATE DENTIFRICE ABRASIVE CONSISTING ESSENTIALLY OF FROM ABOUT 80 TO ABOUT 98 WEIGHT PERCENT OF DICALCIUM ORTHOPHOSPHATE DIHYDRATE AND FROM ABOUT 2 TO ABOUT 20 WEIGHT PERCENT OF PRECIPITATED ANHYDROUS DICALCIUM ORTHOPHOSPHATE, SAID RESULTING DENTIFRICE ABRASIVE BEING FURTHER CHARACTERIZED BY HAVING A DENTIN ABRASION VALUE OF ABOVE 300 TO ABOUT 700.