Patent ID: 7717986

Claim:
A vehicle passenger compartment air filter device comprising a filtration medium comprising (i) a meltblown nonwoven web of electret charged thermoplastic microfibers as a filter layer, said microfibers having an effective fiber diameter (EFD) of greater than 10 μm and comprising a thermoplastic resin having a resistivity greater than 10 14 ohm·cm and an additive selected from fluorochemical compounds or oligomers, organic triazine compounds or oligomers, hindered amine compounds, aromatic amine compounds, nitrogen containing hindered phenols, metal containing hindered phenols and mixtures thereof; said web having a basis weight less than 60 g/m 2 ; and (ii) a gas adsorption layer comprising an adsorbent particle loaded layer and optionally further comprising a support layer and/or a cover layer bonded to said adsorbent layer, wherein basis weight of adsorbent particles in gas adsorption layer is at least 150 g/m 2 ; said filter layer being upstream from the gas adsorption layer and the filter layer and gas adsorption layer being co-pleated and substantially non-bonded to one another except optionally at one or more of the outer edges of the filtration medium; wherein the filter device has an initial particle capture efficiency of at least 90% for 0.4 μm particles, and further wherein the filter device has a particle capture efficiency of at least 87% for 0.4 μm particles during loading at an increase in pressure drop of 50 Pa; wherein the filter device has a loading capacity of at least 60 g/m 2 after an increase in pressure drop of 100 Pa.