Microfiber articles from multi-layer substrates

Abstract

Described are microfiber articles and methods and intermediates for their production, the microfiber articles being preferably produced from co-extruded multi-layer films, and the articles having a multi-layer construction that allows selection of the different layers to have different properties such that the article can have a desired combination of properties.

1 . A multi-layer microfiber article comprising at least one microfiber layer comprising microfibers having an average effective diameter of less than 20 microns and a transverse aspect ratio of from 1.5:1 to 20:1, 
 and a non-microfiber layer comprising a material selected from the group consisting of a polypropylene, a polyethylene, a styrene-ethylenelbutylene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a polyurethane, a fluoropolymer, poly(butylene), poly(isoprene), a nylon, and an adhesive.    
     
     
         2 . The article of  claim 1  wherein the non-microfiber layer is elastomeric.  
     
     
         3 . The article of  claim 1  wherein the non-microfiber layer exhibits a property selected from the group consisting of: elasticity, high or low modulus, puncture resistance, breathability, flame retardancy, temperature resistance, and combinations thereof.  
     
     
         4 . The article of  claim 1  wherein the microfiber layer comprises polypropylene.  
     
     
         5 . The film of  claim 1  comprising a non-microfiber-forming layer sandwiched between two microfiber-forming layers.  
     
     
         6 . The film of  claim 1  wherein the non-microfiber layer comprises an elastomeric polymer.  
     
     
         7 . The film of  claim 1  wherein the film comprises a non-microfiber layer comprising a material selected from the group consisting of a polypropylene, a polyethylene, a styrene-ethylene/butylene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a polyurethane, a fluoropolymer, poly(butylene), poly(isoprene), a nylon, and an adhesive.  
     
     
         8 . The article of  claim 1  wherein the article is co-extruded.  
     
     
         9 . The article of  claim 1  comprising from 2 to 5 layers.  
     
     
         10 . The article of  claim 1  wherein the microfibers have an average effective diameter of less than 5 microns.  
     
     
         11 . The film of  claim 1  wherein the microfibers have an average cross-sectional area of 0.7 2  to 2.1μ 2 .  
     
     
         12 . A method of producing a microfiber article of  claim 1  the method comprising: 
 providing a multi-layer film comprising at least one microfiber-forming layer, and    microfibrillating the microfiber-forming layer to form microfibers.    
     
     
         13 . The method of  claim 12  wherein the film is uniaxially-oriented.