HIGH WET-STRENGTH POLYOLEFIN BLOWN MICROFIBER WEB AND METHOD AND APPARATUS FOR MAKING

摘要

A polyolefin BMF web made from a mixture of polypropylene and surfactant can have high wet strength when a) the surfactant is nonionic and b) the surfactant is mixed with the polypropylene at a static mixer (18) that interconnects the extruder (10) and the BMF die (26). By so postponing the addition of the surfactant, it is protected from both the exceedingly high temperatures of the extruder (10) and from the high shearing forces within the extruder (10). The surfactant also is heated to high temperatures for a much shorter time than if it were premixed with the polypropylene.