Multilayer vent assembly
A vent assembly include a membrane stack, the membrane stack including a plurality of membranes and an air gap between adjacent membranes in the plurality of membranes, wherein each membrane in the plurality of membranes includes a non-fluoropolymer and substantially occlude each other in the membrane stack.
1 . A vent assembly comprising a membrane stack, the membrane stack comprising a plurality of membranes and an air gap between adjacent membranes in the plurality of membranes, wherein each membrane in the plurality of membranes comprises a non-fluoropolymer and substantially occlude each other in the membrane stack, wherein at least one membrane of the plurality of membranes has a bubble point of from 0.2 bar to 10 bar.
2 . The vent assembly of claim 1 , wherein the thickness of each membrane in the plurality of membranes is at least 5 μm.
3 . The vent assembly of claim 1 , wherein the thickness of each membrane in the plurality of membranes is from 5 μm to 200 μm.
4 . The vent assembly of claim 1 , wherein each membrane in the plurality of membranes has a mass per area of at least 2 g/m 2 .
5 . The vent assembly of claim 1 , wherein each membrane in the plurality of membranes has a mass per area of from 2 g/m 2 to 100 g/m 2 .
6 . The vent assembly of claim 1 , wherein each membrane in the membrane stack has an isopropyl alcohol (IPA) rating of less than 30% IPA/water.
7 . The vent assembly of claim 1 , wherein each membrane in the plurality of membranes individually comprise polyethylene (PE), polyurethane (PU), polyamide (PA), or polyimide (PI).
8 . The vent assembly of claim 7 , wherein each membrane in the plurality of membranes individually comprise PE or PU.
9 . The vent assembly of claim 7 , wherein each membrane in the plurality of membranes comprise expanded PE.
10 . The vent assembly of claim 7 , wherein each membrane in the plurality of membranes comprise PU.
11 . The vent assembly of claim 1 , wherein the membrane stack comprises an adhesive layer between adjacent membranes.
12 . The vent assembly of claim 9 , wherein the adhesive layer comprises a heat activated film (HAF) or a pressure sensitive adhesive (PSA).
13 . The vent assembly of claim 1 , wherein the vent assembly has a change in airflow through the vent assembly of less than 80% reduction after a water challenge.
14 . The vent assembly of claim 1 , wherein the vent assembly has a change in water entry pressure (WEP) of less than 80% reduction after a contamination challenge.
15 . The vent assembly of claim 1 , wherein the airflow through the vent assembly is from 0.05 L/hr.
16 . The vent assembly of claim 1 , wherein the airflow through the vent assembly is from 0.05 L/hr to 100 L/hr.
17 . The vent assembly of claim 1 , wherein the plurality of membranes comprises a first membrane, a second membrane and a third membrane and a first air gap is provided between the first membrane and the second membrane and a second air gap is provided between the second membrane and the third membrane.
18 . The vent assembly of claim 17 , wherein the first membrane, the second membrane and the third membrane each individually comprise PE or PU.
19 . The vent assembly of claim 1 , wherein each membrane in the plurality of membranes does not comprise a coating.
20 . The vent assembly of claim 1 , wherein the air gap between adjacent membranes is at least 20 μm.
21 . The vent assembly of claim 1 , wherein, the air gap between the adjacent membranes is from 20 μm to 100 μm.
22 . The vent assembly of claim 1 , wherein each membrane in the plurality of membranes comprise the same material.
23 . A device comprising a vent assembly according to claim 1 .
24 . The device of claim 23 , further comprising a housing defining an aperture and the vent assembly is positioned over the aperture.