Microporous member with interconnected, oriented tapered voids

Claim 1

A microporous membrane of a relatively fluid impermeable material having first and second surfaces, permeated by numerous asymmetric pores comprising a series of sequentially directly interconnected generally tapered voids, wherein substantially all of the generally tapered voids are oriented such that the apexes of said generally tapered voids are directed toward the first surface of the microporous membrane and substantially all of the bases of the generally tapered voids are directed toward the second surface of the microporous membrane, and wherein a fluid, upon passing completely through the microporous membrane will pass through at least three and generally less than 10,000,000 sequentially connected generally tapered voids, and wherein the microporous membrane is greater than about 0.001 micron in thickness and less than about 100 centimeters in thickness, and wherein the average distance across the base of each of the generally tapered voids is greater than about 0.001 micron and less than about 100 micron and wherein the average angle at the apex of each of the generally tapered voids is greater than about 10° and less than about 160°, and wherein the average distance across the ports interconnecting the generally tapered voids is greater than about 0.0002 micron and less than about 100 microns, and wherein the pores interconnecting the voids are fluid impervious so that fluid can only flow through the voids and interconnecting ports and wherein there are on the average at least two and less than 16 ports interconnecting each of the generally tapered voids, and wherein the average number of asymmetric pores passing through the microporous membrane is greater than about 10 per square centimeter.