POROUS POLYTETRAFLUOROETHYLENE FILM, METHOD OF PREPARATION THEREOF, AND AIR FILTER COMPRISING POLYTETRAFLUOROETHYLENE FILM

摘要

FIELD: chemical technology. SUBSTANCE: film is prepared by biaxial extraction of semisintered polytetrafluoroethylene material to degree of extraction of surface of at least 50 and thermal shrinkage of extracted material at temperature higher than polytetrafluoroethylene melting point. Average film pore size ranges from 0.2 mcm to 0.5 mcm, average fibril diameter ranges from 0.005 to 0.2 mcm and film thickness ranges from 0.5 mcm to 15 mcm. EFFECT: improved properties of the film and more efficient preparation method. 5 cl, 25 dwg, 1 tbli