VLIESSTOFFILTER UND VERFAHREN ZUR HERSTELLUNG.

摘要

A filter useful as a cigarette smoke filter is made by convergingly passing a flat restrained meltblown web successively through a heated zone and a trumpet to form a roving. The roving may be processed to make filters. The process results in stretch orientation of longitudinal fibers and bulking due to cross fibers. Primary and secondary pleats formed in the web are bundled into a cylindrical roving. The pleats add bulking to the web and provide fluid permeability through the filter.