Method of fusing high molecular weight polymers at low temperatures

Claim 1

A METHOD FOR PREPARING AN UNSUPPORTED FILM OF A HIGH MOLECULAR WEIGHT OF A CHLOROFLUOROETHYLENIC COMPOUND WHICH COMPRISES PREPARING A SUSPENSION OF SAID POLYMER IN A LIQUID ORGANIC DISPERSING MEDIUM SELECTED FROM THE GROUP CONSISTING OF AN AROMATIC HYDROCARBON LIQUID, THE BULK OF WHICH BOILS AT ATMOSPHERIC PRESSURE ABOVE 160*C. AND HAVING AN EVAPORATION RATE SUCH THAT LESS THAN 35 PERCENT BY WEIGHT OF THE LIQUID IS LOST DURING 120 HOURS AT ROOM TEMPERATURE, AND A HIGH BOILING CHLOROFLUOROCARBON HAVING A BOILING RANGE SUCH THAT THE BULK OF THE MATERIAL BOILS ABOVE 110*C. AT 1 MM. OF MERCURY ABSOLUTE PRESSURE, APPLYING SAID DISPERSION TO A SUPPORTING SURFACE, RAPIDLY RAISING THE TEMPERATURE OF SAID SUSPENSION IN A SUBSTANTIALLY NON-CIRCULATING ATMOSPHERE TO DISSOLVE AT LEAST A PORTION OF THE POLYMER IN A DISPERSING MEDIUM, VOLATILIZING OFF A PORTION OF THE DISPERSING MEDIUM IN A CIRCULATING ATMOSPHERE AT AN ELEVATED TEMPERATURE, MAINTAINING THE SURROUNDING TEMPERATURES AT ALL STAGES NOT HIGHER THAN 300*C., REMOVING THE RESULTING SOFT PARTIALLY DRIED FILM FROM THE SUPPORT BEFORE IT HAS ADHERED FIRMLY AND THEN SUBSTANTIALLY COMPLETELY DRIVING OFF THE DISPERSING MEDIUM.