Patent ID: 9415347
Filing Date: 2016-08-16
CPC Classification: B01D

Claim Text:
1. An asymmetric membrane comprising (a) a first exterior porous surface; (b) a second exterior porous surface; (c) a porous bulk between the first exterior porous surface and the second exterior porous surface, the porous bulk having a first porous region and a second porous region, the first porous region contacting the second porous region; (d) a first asymmetric porous zone, the first asymmetric porous zone including the first exterior porous surface and a first asymmetric porous zone boundary in the porous bulk, and extending into, and including, the first porous region of the bulk to the first asymmetric zone boundary; and, (e) a second asymmetric porous zone, the second asymmetric porous zone including the second exterior porous surface and a second asymmetric porous zone boundary in the porous bulk, and extending into, and including, the second porous region of the bulk to the second asymmetric zone boundary; wherein the first porous asymmetry has a ratio of asymmetry from the first exterior porous surface to the first asymmetric zone boundary in the range of from about 1.1 to about 5, and the second porous asymmetry has a ratio of asymmetry from the second exterior porous surface to the second asymmetric zone boundary in the range of from about 2 to about 10.