Nonwoven substrates having fibrils

Abstract

The present invention relates to a nonwoven substrate comprising a layer of fibers, wherein a plurality of the fibers each comprise a plurality of fibrils extending outwardly from a surface of the fibers, and wherein the plurality of fibrils comprise a lipid ester.

1 . A nonwoven substrate comprising a layer of fibers, wherein a plurality of the fibers each comprise a plurality of fibrils extending outwardly from a surface of the fibers, and wherein the plurality of fibrils comprise a lipid ester. 
     
     
         2 . The nonwoven substrate of  claim 1 , wherein the plurality of fibers are formed from a composition comprising a polyolefin and the lipid ester, and wherein the composition comprises at least 11% of the lipid ester, by weight of the composition, wherein the lipid ester has preferably a melting point in the range of 40° C. to 150° C. 
     
     
         3 . The nonwoven substrate of  claim 1 , wherein the average length of the fibrils from the surfaces of the fibers to free ends of the fibrils is in the range of about 0.5 μm to about 20 μm. 
     
     
         4 . The nonwoven substrate of  claim 1 , wherein the average hydraulic diameter of the fibrils is in the range of about 100 nm to about 800 nm. 
     
     
         5 . The nonwoven substrate of  claim 1 , wherein the layer of fibers comprises spunbond fibers, meltblown fibers, or fine fibers. 
     
     
         6 . The nonwoven substrate of  claim 1 , wherein at least some of the fibrils extend radially outwardly from the surface of the fibers in a central longitudinal third of at least some of the fibers. 
     
     
         7 . The nonwoven substrate of  claim 1 , wherein the plurality of the fibrils grow out of the surface of the fibers at least 24 hours post-nonwoven substrate formation under ambient conditions. 
     
     
         8 . The nonwoven substrate of  claim 1 , wherein the fibers comprising the plurality of fibrils are free of droplets of the lipid ester. 
     
     
         9 . A nonwoven substrate comprising a layer of fibers, wherein the layer of fibers comprises a plurality of bonds, each bond comprising a bond area, and wherein a plurality of fibrils extend outwardly from a surface of at least one of the bond areas. 
     
     
         10 . The nonwoven substrate of  claim 1 , wherein the plurality of fibrils consist essentially of a lipid ester. 
     
     
         11 . The nonwoven substrate of  claim 9 , wherein the plurality of fibrils comprise glycerol tristearate, and wherein the glycerol tristearate has a melting temperature above 35° C. and/or wherein a plurality of the fibers comprise fibrils extending radially outwardly from a surface of the fibers and/or wherein the nonwoven substrate comprises a second layer of fibers, and wherein the fibers of the second layer of fibers are substantially free of fibrils and/or wherein the nonwoven substrate comprises a second layer of fibers, and wherein a plurality of fibrils extend radially outwardly from a surface of at least some of the fibers in the second layer of fibers and/or wherein the nonwoven substrate comprises a second layer of fibers, wherein the layer of fibers comprises spunbond fibers, and wherein the second layer of fibers comprises meltblown fibers or fine fibers and/or wherein the fibers are formed from a composition comprising at least 11% of a lipid ester, by weight of the composition. 
     
     
         12 . A nonwoven substrate comprising a layer of fibers, wherein a plurality of the fibers comprise fibrils extending outwardly therefrom only after a time period, and wherein the time period is greater than about 24 hours post-nonwoven substrate formation under ambient conditions. 
     
     
         13 . The nonwoven substrate of  claim 12 , wherein the time period is greater than about 100 hours post-nonwoven substrate formation under ambient conditions. 
     
     
         14 . The nonwoven substrate of  claim 12 , wherein the fibrils are a first color, wherein the plurality of fibers are a second color, and wherein the first color and the second color are different. 
     
     
         15 . The nonwoven substrate of  claim 12 , wherein the plurality of fibers are free of droplets of a lipid ester. 
     
     
         16 . The nonwoven substrate of  claim 9 , wherein the plurality of fibrils consist essentially of a lipid ester.