Respiratory filter apparatus and method

Publication Date

December 19, 1995

Patent Number

US5253641A

Abstract

An antifogging plastic material is disclosed that is particularly suitable for use as a disposable fog-resistant lens. The lens material comprises a substantially transparent polyester substrate; a layer of polyvinylidene chloride-containing polymer on the polyester substrate; a water permeable colloid layer on the polyvinylidene chloride-containing layer; and a polyvinyl alcohol-containing layer on the water permeable colloid layer.