Process for hydrophilicization of hydrophobic polymers

Abstract

A process for rendering the surfaces of polymeric plastic or rubber materials, which are intrinsically non-polar or only slightly polar, and hydrophobic, polar or more polar, and hydrophilic, so that amine-containing functional groups, and ultimately, a durable tenaciously adhering, slippery polyurethane or polyurethane-urea hydrogel coating may subsequently be applied to the polymer surface, is disclosed. The process involves dual plasma-treatment of a polymeric plastic or rubber substrate material; the first treatment being with an oxygen-containing plasma gas, to affix hydroxyl, carboxyl and carbonyl groups to the substrate surface, thereby rendering the surface more polar and activated; and the second treatment being with a nitrogen-containing plasma gas, to affix amine and amino groups to the substrate surface to make it more hydrophilic and reactive toward terminal isocyanate groups of a polyurethane or polyurethane/urea prepolymer adduct intermediate tie-coat which is subsequently applied to the substrate surface and then converted to a tenaciously adhering, slippery hydrogel coating. The process is especially suited to the hydrophilicization of intrinsically non-polar and hydrophobic polymeric plastic materials, such as polyethylenes, nylons-11 and nylons-12.