US Patent 7152601 Strapless respiratory face mask

The present invention relates to face masks to control and improve the quality of inhaled air. Claimed and described is a respiratory face mask comprising a flange and a filter layer, the flange having an inner periphery and an outer periphery and a first and a second width measured perpendicular to the inner periphery between the inner periphery and the outer periphery, characterised in that the first width is greater than the second width. Preferably, such face masks are strapless and rely on a hydrogel adhesive for attachment and sealing. Further claimed and described is an improved cover layer for an adhesive of such a face mask.