VINYLIDENE FLUORIDE RESIN SPLIT YARN, PROCESS FOR PRODUCTION THEREOF AND FILTER COMPRISING THE SAME

摘要

A vinylidene fluoride resin having an inherent viscosity of 0.8 to 1.4 dl/g in dimethylformamide is melt-extruded and cooled and solidified under draft-stretching to form a film having a birefringence of 25 x 10-3 or larger. The film is heattreated at 80 - 120 .degree.C and split into a split yarn. The split yarn has a Young's modulus even higher than that of the polypropylene split yarn and, when provided with a surface charge above the glass transition temperature, retains the charge semi-permanently. The charged split yarn is particularly suitable for forming a gas filter.