Nonwoven breathable composite barrier fabric

Abstract

A breathable barrier material having a first nonwoven layer and a first microporous film bonded together to form a composite laminate. A second microporous film and a second nonwoven layer are bonded to the composite laminate and second film to form the barrier material such that the films are disposed between the nonwoven layers. The composite laminate is bonded to the second film and second nonwoven layer thereby creating bond points in the material and void spaces between the first and second films. The void spaces between films may enhance liquid and viral barrier properties in the barrier material by creating a boundary that minimizes passage of liquids and/or viral components through the barrier material.

We claim:  
     
         1 . A breathable barrier material comprising: 
 a first nonwoven layer;    a first microporous film bonded to the first nonwoven layer to form a composite laminate;    a second microporous film; and    a second nonwoven layer bonded to the composite laminate and second film to form the barrier material.    
     
     
         2 . The material of  claim 1  wherein the first and second films are disposed between the nonwoven layers.  
     
     
         3 . The material of  claim 1  wherein one of the nonwoven layers comprises a spunbond web.  
     
     
         4 . The material of  claim 1  wherein the first and second nonwoven layers comprise first and second spunbond webs.  
     
     
         5 . The material of  claim 1  wherein one of the nonwoven layers comprises at least one layer of a meltblown polyolefin and at least one layer of a spunbond polyolefin.  
     
     
         6 . The material of  claim 1  wherein one of the films comprises a monolayer film.  
     
     
         7 . The material of  claim 1  wherein one of the films comprises a multilayer film.  
     
     
         8 . The material of  claim 7  wherein the multilayer film comprises a core layer constituting about 85% of the total film thickness and a skin layer constituting about 15% of the total film thickness.  
     
     
         9 . The material of  claim 7  wherein the multilayer film comprises a core layer constituting about 85% of the total film thickness and two skin layers each constituting about 7.5% of the total film thickness disposed on opposite sides of the core layer.  
     
     
         10 . The material of  claim 1  wherein one of the films comprises from about 30% to about 75% by weight polyolefin resin and from about 70% to about 25% by weight of filler having an average size less than about 10 microns.  
     
     
         11 . The material of  claim 7  wherein each of the film layers comprise from about 30% to about 75% by weight polyolefin resin and from about 70% to about 25% by weight of filler having an average size less than about 10 microns.  
     
     
         12 . The material of  claim 1  wherein one of the films comprises from about 30% to about 45% by weight polyolefin resin and from about 70% to about 55% by weight of filler.  
     
     
         13 . The material of  claim 7  wherein each of the film layers comprise from about 30% to about 45% by weight polyolefin resin and from about 70% to about 55% by weight of filler.  
     
     
         14 . The material of  claim 1  wherein the laminate has a water vapor transmission rate of at least about 500 grams per square meter per 24 hours.  
     
     
         15 . The material of  claim 1  wherein the laminate has a water vapor transmission rate of at least about 5000 grams per square meter per 24 hours.  
     
     
         16 . The material of  claim 1  wherein the laminate has a water vapor transmission rate of from about 500 to about 5000 grams per square meter per 24 hours.  
     
     
         17 . The material of  claim 1  wherein the nonwoven layers comprise about 98% random copolymer of polypropylene and polyethylene with 1.5-3.5% ethylene content.  
     
     
         18 . The material of  claim 1  wherein one of the nonwoven layers comprises an antistatic treatment.  
     
     
         19 . The material of  claim 1  wherein the material is thermally bonded.  
     
     
         20 . The material of  claim 1  comprising a surgical gown.  
     
     
         21 . The material of  claim 1  comprising a surgical drape.  
     
     
         22 . The material of  claim 1  comprising a sterilization peel pouch.  
     
     
         23 . The material of  claim 1  comprising an industrial protective garment.  
     
     
         22 . The material of  claim 1  comprising a thermoplastic elastomeric polyolefin.  
     
     
         24 . The material of  claim 1  comprising a personal care article.  
     
     
         25 . The material of  claim 1  comprising bonding the composite laminate to the second film and second nonwoven layer so that the material is breathable, maintains fluid barrier properties, and passes bacteriophage testing in compliance with ASTM F 1671-97b.  
     
     
         26 . The material of  claim 1  comprising void spaces between the first and second films.  
     
     
         27 . The material of  claim 1  comprising thermally bonding the composite laminate to the second film and second nonwoven layer to create bond points in the material and void spaces between the first and second films.