Process for dimensionally stabilizing articles fabricated from polytetrafluoroethylene

Claim 1

A PROCESS FOR FABRICATING ARTICLES SUBSTANTIALLY COMPOSED OF POLYTETRAFLUOROETHYLENE AND HAVING SUBSTANTIALLY STABLE DIMENSION AND SHAPE, SAID PROCESS COMPRISING THE STEPS OF SUBJECTING FINELY DIVIDED GRANULES OF FIBROUS OR ERYSTALLINE POLYTETRAFLUOROETHYLENE TO PRESSURE TO FORM A BODY SUBSTANTIALLY HAVING A PRESELECTED SHAPE AND PRESELECTED DIMENSIONS, BAKING SAID BODY UNDER SAID PRESSURE DURING A PRESELECTED TIME INTERVAL SUBSTANTIALLY AT A TEMPERATURE SUFFICIENT TO CONVERT SAID FIBROUS BODY TO AN AMORPHOUS GEL, THEREAFTER REDUCING THE BAKING TEMPERATURE THE MINIMUM AMOUNT NECESSARY TO CONVERT SAID AMORPHOUS GEL TO A FIBROUS POLYTETRAFLUOROETHYLENE BODY HAVING A SHAPE AND DIMENSIONS MORE PRECISELY APPROACHING THE PRESELECTED SHAPE AND DIMENSIONS DESIRED, REMOVING SAID FORMING PRESSURE FROM SAID MORE PRECISELY SHAPED AND DIMENSIONED FIBROUS BODY, CONTINUING SAID BAKING AT SAID REDUCED TEMPERATURE DURING A TIME INTERVAL OF AT LEAST 20 HOURS BUT INSUFFICIENT TO CAUSE SAID MORE PRECISELY SHAPED AND DIMENSIONED FIBROUS BODY TO LOSE ANY SIGNIFICANT AMOUNT OF WEIGHT WHILE BEING SUFFICIENT TO SUBSTANTIALLY RELIEVE ALL INTERNAL STRESSES WHICH MIGHT OTHERWISE CAUSE SAID MORE PRECISELY SHAPED AND DIMENSIONED FIBROUS BODY TO SUBSTANTIALLY DEVIATE IN SHAPE AND DIMENSION AFTER ALL BAKING IS STOPPED.