Liquid Barrier Nonwoven Fabrics with Ribbon-Shaped Fibers

Abstract

A nonwoven fabric useful as a component in a personal hygiene product and a nonwoven personal hygiene component, which is substantially free or free of non-ribbon shaped (e.g., round-shaped) spunbond fibers and includes a meltblown layer between and in direct contact with ribbon-shaped spunbond layers. The meltblown layer has a basis weight of at least about 0.008 gsm and not greater than about 5 gsm, and the nonwoven fabric or component has a basis weight of at least about 8 gsm and not greater than about 40 gsm, a pore size of less than or equal to about 27 microns when measured at 10% of cumulative filter flow. The nonwoven fabric also can have a low surface tension liquid strike through flow of less than 0.9 ml per second, a ratio of low surface tension liquid strike through flow to air permeability of greater than or equal to about 0.016, or both. Personal hygiene articles can incorporate the nonwoven fabric or component.

1 - 20 . (canceled) 
     
     
         21 . A method of forming a nonwoven fabric, comprising:
 (i) providing or forming a first spunbond layer comprising a first plurality of ribbon-shaped continuous filaments;   (ii) directly depositing a meltblown layer onto the first spunbond layer from a die having a die-to-collector distance from about 110 mm to about 150 mm;   (iii) depositing a second spunbond layer comprising a second plurality of ribbon-shaped continuous filaments directly onto the meltblown layer; and   (iv) consolidating the first spunbond layer, the meltblown layer, and the second spunbond layer together to form the nonwoven fabric.   
     
     
         22 . The method of  claim 21 , wherein the meltblown layer comprises meltblown fibers in an amount of at least 0.1% by weight of the nonwoven fabric and not greater than about 40% by weight of the nonwoven fabric. 
     
     
         23 . The method of  claim 21 , wherein the meltblown layer has a basis weight no greater than 5 gsm. 
     
     
         24 . The method of  claim 21 , wherein at least one of the first spunbond layer, the second spunbond layer, and the meltblown layer comprise polypropylene. 
     
     
         25 . The method of  claim 24 , wherein each of the first spunbond layer, the second spunbond layer, and the meltblown layer comprises polypropylene. 
     
     
         26 . The method of  claim 21 , wherein the nonwoven fabric contains less than about 10% by weight non-ribbon shaped spunbond fibers, and wherein the nonwoven fabric has a basis weight of at least about 8 gsm and not greater than about 40 gsm. 
     
     
         27 . The method of  claim 21 , wherein the meltblown layer consists of (i) from 1% to 10% by weight of non-ribbon shaped meltblown fibers, and (ii) ribbon-shaped meltblown fibers. 
     
     
         28 . The method of  claim 21 , wherein the nonwoven fabric has a pore size of about 14.5 microns to less than or equal to about 21 microns when measured at 10% of cumulative filter flow. 
     
     
         29 . The method of  claim 21 , wherein the nonwoven fabric has a low surface tension liquid strike through flow of less than 0.9 ml per second, an air permeability of at least 10 m 3 /m 2 /min. and a ratio of low surface tension liquid strike through flow to air permeability of greater than or equal to 0.016 and less than or equal to 0.021. 
     
     
         30 . The method of  claim 21 , wherein at least one of the first plurality of ribbon-shaped continuous filaments and the second plurality of ribbon-shaped continuous filaments comprises fibers having a cross-section with an aspect ratio of at least 2.5:1 and no great than about 7:1. 
     
     
         31 . The method of  claim 21 , wherein the depositing a meltblown layer comprises depositing a first meltblown layer directly onto the first spunbond layer from a first die having a first die-to-collector distance from about 110 mm to about 150 mm and depositing at least a second meltblown layer directly onto the first meltblown layer from a second die having a second die-to-collector distance from about 110 mm to about 150 mm. 
     
     
         32 . The method of  claim 21 , wherein consolidating the first spunbond layer, the meltblown layer, and the second spunbond layer together to form the nonwoven fabric comprises a thermal bonding operation. 
     
     
         33 . The method of  claim 32 , wherein the thermal bonding operation forms a plurality of discrete bond areas 
     
     
         34 . A nonwoven fabric, comprising:
 a first spunbond layer comprising a first plurality of ribbon-shaped continuous filaments;   a second spunbond layer comprising a second plurality of ribbon-shaped continuous filaments; and   a meltblown layer disposed between the first spunbond layer and the second spunbond layer, wherein said meltblown layer has a basis weight of not greater than about 5 gsm;   wherein the nonwoven fabric has a basis weight of at least 8 gsm and not greater than about 40 gsm, a low surface tension liquid strike through flow of less than 0.9 ml per second, an air permeability of at least 10 m 3 /m 2 /min. and a ratio of low surface tension liquid strike through flow to air permeability of greater than or equal to 0.016 and less than or equal to 0.021;   wherein the meltblown layer has been deposited directly onto the second ribbon-shaped spunbond layer from at least one die having a die-to-collector distance from about 110 mm to about 150 mm.   
     
     
         35 . The nonwoven fabric of  claim 34 , wherein the nonwoven fabric has a pore size of about 14.5 microns to less than or equal to about 21 microns when measured at 10% of cumulative filter flow. 
     
     
         36 . The nonwoven fabric of  claim 34 , wherein at least one of the first spunbond layer and second spunbond layer comprises fibers having a cross-section with an aspect ratio of at least 2.5:1 and no great than about 7:1. 
     
     
         37 . The nonwoven fabric of  claim 34 , wherein the meltblown layer consists of (i) from 1% to 10% by weight of non-ribbon shaped meltblown fibers, and (ii) ribbon-shaped meltblown fibers 
     
     
         38 . The nonwoven fabric of  claim 34 , wherein the meltblown layer comprises multiple directly adjoining meltblown sub-layers. 
     
     
         39 . The nonwoven fabric of  claim 34 , wherein the nonwoven fabric contains less than about 10% by weight non-ribbon shaped spunbond fibers. 
     
     
         40 . The nonwoven fabric of  claim 34 , wherein the first spunbond layer, the second spunbond layer, and the meltblown layer are bonded together by a plurality of discrete bond areas.