Micro and nanofiber nonwoven spunbonded fabric

Abstract

The invention provides methods for the preparation of nonwoven spunbonded fabrics and various materials prepared using such spunbonded fabrics. The method generally comprises extruding multicomponent fibers having an islands in the sea configuration such that upon removal of the sea component, the island components remain as micro- and nanofibers. The method further comprises mechanically entangling the multicomponent fibers to provide a nonwoven spunbonded fabric exhibiting superior strength and durability without the need for thermal bonding.

That which is claimed: 
     
         1 . A nonwoven spunbonded fabric, comprising: mechanically entangled multicomponent fibers, said multicomponent fibers having a predetermined average diameter and having an islands in the sea configuration comprising a plurality of island components comprising a first polymer surrounded by a sea component comprising a second polymer; said fabric being devoid of thermal bonds. 
     
     
         2 . The fabric of  claim 1 , wherein the multicomponent fibers comprise an outer surface, and wherein the sea component completely surrounds the island components such that none of the island components form any portion of the outer surface of the multicomponent fibers. 
     
     
         3 . The fabric of  claim 2 , wherein the sea component completely surrounds the island components such that the sea component forms a sheath around the island components, the sheath having a thickness measured between the outer surface of the multicomponent fiber and the islands nearest the outer surface of the multicomponent fiber. 
     
     
         4 . The fabric of  claim 3 , wherein the sheath has a thickness that is greater than or equal to an average diameter of the island components. 
     
     
         5 . The fabric of  claim 1 , wherein said multicomponent fibers comprise extruded fibers having an average diameter in the range of about 5 μm to about 25 μm. 
     
     
         6 . The fabric of  claim 1 , wherein said multicomponent fibers comprise extruded fibers having an average diameter in the range of about 10 μm to about 20 μm. 
     
     
         7 . The fabric of  claim 1 , wherein said multicomponent fibers comprise extruded fibers having an average diameter in the range of about 50 nm to about 5 μm. 
     
     
         8 . The fabric of  claim 1 , wherein the island components have an average diameter in the range of about 50 nm to about 1 μm. 
     
     
         9 . The fabric of  claim 8 , wherein the island components have an average diameter in the range of about 100 nm to about 800 nm. 
     
     
         10 . The fabric of  claim 1 , wherein said multicomponent fibers comprising between about 2 and about 1000 island components. 
     
     
         11 . The fabric of  claim 1 , wherein said multicomponent fibers comprise between about 36 and about 400 island components. 
     
     
         12 . The fabric of  claim 1 , wherein said multicomponent fibers comprise an island/sea ratio in the range of about 75/25 to about 25/75. 
     
     
         13 . The fabric of  claim 1 , wherein the first polymer is different from the second polymer. 
     
     
         14 . The fabric of  claim 1 , wherein the first polymer comprises a polyamide. 
     
     
         15 . The fabric of  claim 1 , wherein the first polymer comprises a polymer selected from the group consisting of polyolefins, polyamides, polyesters, thermoplastics, and combinations thereof. 
     
     
         16 . The fabric of  claim 1 , wherein the second polymer comprises a polymer selected from the group consisting of polyvinyl alcohol, poly(lactic) acid, co-PET, and combinations thereof. 
     
     
         17 . The fabric of  claim 1 , wherein the first polymer comprises nylon and the second polymer comprises PLA. 
     
     
         18 . The fabric of  claim 1 , wherein the spunbonded fabric comprises a first surface and an opposing surface, and wherein said mechanically entangled multicomponent fibers are present only one of the surfaces. 
     
     
         19 . The fabric of  claim 1 , wherein the spunbonded fabric comprises a first surface and an opposing surface, and wherein said mechanically entangled multicomponent fibers are present on the first surface and the opposing surface. 
     
     
         20 . The fabric of  claim 1 , wherein the fabric exhibits an MD tensile strength of at least about 25 N when normalized to a 100 g/m 2  basis. 
     
     
         21 . The fabric of  claim 1 , wherein the fabric exhibits a CD tensile strength of at least about 25 N when normalized to a 100 g/m 2  basis. 
     
     
         22 . The fabric of  claim 1 , wherein the fabric exhibits an MD tear strength of at least about 25 N when normalized to a 100 g/m 2  basis. 
     
     
         23 . The fabric of  claim 1 , wherein the fabric exhibits a CD tensile strength of at least about 50 N when normalized to a 100 g/m 2  basis. 
     
     
         24 . The fabric of  claim 1 , wherein the fabric exhibits an absorbent capacity of at least about 5 cm 3 /g. 
     
     
         25 . The fabric of  claim 1 , wherein the fabric exhibits an absorbency rate of at least about 0.025 cm 3 /g·s. 
     
     
         26 . The fabric of  claim 1 , wherein the fabric exhibits an air permeability of at least about 5 (cm 3 /s)/cm 2 . 
     
     
         27 . An article prepared using the fabric of  claim 1 , wherein the article is selected from the group consisting of liquid filters, air filters, barrier fabrics, technical wipes, personal care wipes, and artificial leather products.