Fundamental approach

Background

•The use of NOA places more importance on the filter media. Fines are generally more finely dispersed due to the lack of agglomeration.

•Filter weight and air-permeability are important properties to consider.

•The historic move was away from cotton-based to non-woven PE or PP with thermal bonding (no chemical bonding). PP tends to drag out more mineral oil.

•Some research uses maleic acid, bonded to the fibres, to create chemical filtration effect.