Patent ID: 8758488

Claim:
A vent for a container, said vent being permeable to gas or vapor but impermeable to liquid, the vent comprising: a stiff substrate of polymer material, the substrate having an array of discrete through holes therethrough in spaced relation to one another to define the areas therebetween; a membrane comprised of a first layer of porous polytetrafluoroethylene, a thin layer of a thermoplastic bather polymer having a consistent thickness, a second layer of porous polytetrafluoroethylene, and a fabric layer adhered to one of the layers of porous polytetrafluoroethylene wherein the membrane is thermally bonded to at least one side of the substrate with a thermal bond that includes bonding in the areas between the through holes, the thermal bond being an interface between the substrate and membrane which is direct and free of adhesive.