Aramid nonwoven fabric and preparation method therefor

Abstract

An aramid nonwoven fabric showing more improved tenacity and superior heat-insulating property, and a method of preparing the same. The aramid nonwoven fabric is what includes 10 to 100 wt % of para-aramid staple fibers and 0 to 90 wt % of meta-aramid staple fibers, and has an air permeability of 40 to 200 cm 3 /cm 2 /sec and an average pore size of 20 to 50 μm. Such aramid nonwoven fabric can be prepared by carding aramid fibers including the para-aramid staple fibers and the meta-aramid staple fibers so as to form a web, needle-punching the same, and water-punching the same with a prescribed water pressure.

What is claimed is: 
     
         1 . An aramid nonwoven fabric, including 10 to 100 wt % of para-aramid staple fibers and 0 to 90 wt % of meta-aramid staple fibers, and having an air permeability of 40 to 200 cm 3 /cm 2 /sec and an average pore size of 20 to 50 μm. 
     
     
         2 . The aramid nonwoven fabric according to  claim 1 , including 50 to 100 wt % of the para-aramid staple fibers and 0 to 50 wt % of the meta-aramid staple fibers. 
     
     
         3 . The aramid nonwoven fabric according to  claim 1 , wherein the para-aramid staple fibers or the meta-aramid staple fibers have an average length of 25 to 100 mm and an average thickness of 5 to 20 μm. 
     
     
         4 . The aramid nonwoven fabric according to  claim 1 , having a density of 0.05 to 0.2 g/cm 3  and a thickness of 0.60 to 1.90 mm. 
     
     
         5 . The aramid nonwoven fabric according to  claim 1 , wherein the tensile strength at the fiber direction (MD, machine direction) is 0.30 to 0.55 kgf/mm 2  and the tensile strength at the perpendicular direction (CD, cross direction) is 0.25 to 0.80 kgf/mm 2 . 
     
     
         6 . The aramid nonwoven fabric according to  claim 1 , wherein the tear strength is 3.50 to 7.50 kgf and the breaking work is 430 to 1150 kgf·mm at the fiber direction (MD), and the tear strength is 3.50 to 6.50 kgf and the breaking work is 830 to 1600 kgf·mm at the perpendicular direction (CD). 
     
     
         7 . The aramid nonwoven fabric according to  claim 1 , which is used for an industrial heat-resistant filter or an industrial heatproof suit.