Process for blending a hot polyester resin with a high boiling polymerizable monomeric material in the presence of a heat-transfer liquid

Claim 1

A PROCESS COMPRISING BLENDING A HOT UNSATURATED POLYESTER RESIN, SAID RESIN HAVING A TEMPERATURE AT THE TIME OF BLENDING BETWEEN 150*C. AND 250*C. AND SAID RESIN HAVING BEEN PREPARED BY REACTING A POLYHYDRIC ALCOHOL WITH AN ALPHA, BETA-ETHYLENICALLY UNSATURATED DICARBOXYLIC ACID WITH A POLYMERIZABLE MONOMERIC MATERIAL HAVING A BOILING POINT ABOVE 250*C. IN THE PRESENCE OF A HEAT-TRANSFER LIQUID MATERIAL HAVING A BOILING POINT BELOW 200*C. WHILE SUBJECTING THE SYSTEM TO A VACUUM, VARYING BETWEEN ABOUT 90 MM. OF MERCURY AND 736.6 MM. OF MERCURY, ABSOLUTE PRESSURE, WITH TEMPERATURES OF THE MONOMERIC MATERIAL ADMIXED WITH THE HEAT TRANSFER MATERIAL HELD CORRESPONDINGLY FROM ABOUT 50*C. TO 100*C., WHEREBY THE HEAT-TRANSFER LIQUID IS VOLATILIZED SO AS TO REMOVE SENSIBLE HEAT FROM THE SYSTEM, CONDENSING THE HEAT-TRANSFER LIQUID AND RETURNING SAID LIQUID TO THE SYSTEM UNTIL THE HOT UNSATURATED POLYESTER RESIN ADDITION IS COMPLETED, THEREAFTER REMOVING SAID HEAT-TRANSFER LIQUID FROM THE SYSTEM.