Process for coating particles with a thermosetting phenolic resin

Claim 1

A PROCESS FOR THE PRODUCTION OF DISCRETE, FREE-FLOWING INERT FILLER PARTICLES COATED WITH A POTENTIALLY THERMOSETTING PHENOLIC RESIN COMPOSITION WHICH COMPRISES MIXING TOGETHER (A) SAID INERT FILLER PARTICLES, (B) A COMMINUTED PHENOLIC RESIN IN AN AMOUNT FROM ABOUT 1 TO ABOUT 35 PERCENT BY WEIGHT OF THE TOTAL COMPOSITION WHICH COMPRISES THE REACTION PRODUCT OF BETWEEN ABOUT 0.5 AND ABOUT 0.85 MOLE FORMALDEHYDE PER MOLE OF PHENOL, (C) HEXAMETHYLENETETRAMINE IN AN AMOUNT SUFFICIENT TO RENDER SAID PHENOLIC RESIN (B) THERMOSETTING, AND (D) A COATING AGENT COMPRISING (1) WATER AND (2) A VOLATILE ORGANIC SOLVENT HAVING A VAPOR PRESSURE HIGHER THAN THAT OF WATER AND WHICH IS A MUTUAL SOLVENT FOR BOTH SAID PHENOLIC RESIN (B) AND WATER, SAID VOLATILE ORGANIC SOLVENT BEING SELECTED FROM THE GROUP CONSISTING OF METHYL ALCOHOL, ETHYL ALCOHOL, ISOPROPYL ALCOHOL, N-PROPYL ALCOHOL, ACETONE, METHYL ETHYL KETONE, METHYL ACETATE AND MIXTURES THEREOF, WHEREIN THE AMOUNT OF ORGANIC SOLVENT (2) IS FROM ABOUT 35 TO ABOUT 95 PERCENT BY WEIGHT OF SAID SAID COATING AGENT (D) AND THE RATIO BY WEIGHT OF SAID COATING AGENT (D) TO SAID PHENOLIC RESIN (B) IS FROM ABOUT 0.1 TO 1 AND 2 TO 1, CONTINUING THE MIXING UNTIL SAID RESIN-COATED INERT FILLER PARTICLES BECOME SUBSTANTIALLY DRY AND FREE-FLOWING.