Patent ID: 7717975

Claim:
A web comprising a substantially continuous fine fiber layer, formed on a non-woven filtration substrate, the fine fiber layer having a layer thickness of 0.5 to 500 microns, the layer comprising a spacer means comprising an inert spacer particulate with a particle size of 0.05 to 200 microns dispersed throughout the fiber in the layer, the inert spacer particulate present in an amount of 0.1 to 50 vol %; the fiber the fiber having a diameter of about 0.0001 to about 2 microns, and the layer having a fine fiber solidity of about 0.1 to 50%, wherein the permeability of the layer is greater than the permeability of a fine fiber layer formed without the spacer particulate and solidity is less than the solidity of a fine fiber layer formed without the spacer particulate.