Nonwoven fabrics and methods for heat treating them

摘要

A nonwoven fabric comprises fibers which comprise polyethylene, the nonwoven fabric having a chemical agent applied thereon and having a Frazier air permeability of at least 5 m 3 /min/m 2 and characterized by less than 1.2 stretch-type defects/m 2 . The invention also relates to a method for heat treating a multiple component nonwoven fabric comprising a first polymeric component and a second polymeric component, the first polymeric component having a melting point or softening point that is lower than the melting point or softening point of the second polymeric component, comprising heating the nonwoven fabric to a temperature that is greater than about (T m - 40)°C, where T m is the melting or softening point of the first polymeric component, but less than (T m - 10)°C, while the nonwoven fabric is under a tension in any one direction that is between 0 and 52.5 N/m