Microperforated polymeric film and methods of making and using the same

Abstract

Described herein are microperforated polymeric films comprising: opposed first and second surfaces separated by a first certain distance; and a plurality of channels perpendicular to the first and second surfaces, wherein a first opening of a channel intersects the first surface and a second opening of the channel intersects the second surface; wherein the diameter of the first opening is larger than the diameter of the second opening and the second openings on the second surface are spaced apart by a second certain distance; wherein the ratio of the first certain distance to the second certain distance is at least 0.25; and further wherein the second surface has an open area of at least 10%. Also described are methods of making and using such microperforated polymeric films.

What is claimed is: 
     
         1 . A microperforated polymeric film comprising: comprising: (i) opposed first and second surfaces separated by a first certain distance; and (ii) a plurality of channels perpendicular to the first and second surfaces, wherein a first opening of each channel intersects the first surface and a second opening of each channel intersects the second surface; wherein the diameter of the first opening is larger than the diameter of the second opening and the second openings on the second surface are spaced apart by a second certain distance; wherein the ratio of the first certain distance to the second certain distance is at least 0.25; and further
 wherein the second surface has an open area of at least 10%.   
     
     
         2 . The microperforated polymeric film of  claim 1 , wherein the distance between the opposed first and second surfaces is at least 75 micrometers. 
     
     
         3 . The microperforated polymeric film according to  claim 1 , wherein the microperforated polymeric film is selected from a polyolefin. 
     
     
         4 . The microperforated polymeric film according to  claim 1 , wherein the channel has tapered walls. 
     
     
         5 . The microperforated polymeric film according to  claim 1 , wherein the second opening is elliptical or round in shape. 
     
     
         6 . The microperforated polymeric film according to  claim 1 , wherein the second openings are less than 500 microns in diameter. 
     
     
         7 . The microperforated polymeric film according to  claim 1 , further comprising at least one of embedded fibers, or integral ribs extending along at least one major surface. 
     
     
         8 . The microperforated polymeric film according to  claim 1 , wherein the second certain distance is at least 75 micrometers. 
     
     
         9 . A multilayered filter device comprising:
 (a) the microperforated polymeric film according to  claim 1 ; and   (b) a second permeable material extending across at least a portion of the microperforated polymeric film.   
     
     
         10 . The multilayered filter device of  claim 9 , wherein the plurality of spacers is integral with at least one of the microperforated polymeric film or the second permeable material. 
     
     
         11 . A method of filtering particulates comprising:
 (a) providing a microperforated polymeric film according to  claim 1 ;   (b) providing a mixture comprising particulates; and   (c) contacting the mixture to the microperforated polymeric film so as to filter the mixture.   
     
     
         12 . The method of filtering particulates of  claim 11 , wherein the mixture is a paint.