| abstract |
Dipcoated Rx spectacle lenses require coating scratch resistance, tinting and/or AR coating processes. Chemically, fully-hydrolized copolymers of amino silane and epoxide silane form the chemical backbone of these heat-curing hardcoats, although polyfunctional organic resin modifiers may also "co-cure" into the backbone. The liquid coating copolymer is made in three chemical reactions: (1) fully hydrolizing the two silane Components A&B separately, with a stoichemetric excess of water; (2) ketimine formation, to latently cap the amine functionality; (3) "bodying" the liquid hardcoating to a desired degree of copolymerization, by reacting together the fully hydrolized ketimine silane Component B with the fully hydrolized epoxide-functional silane Component A. Dilution is with the selected resin modifier(s) ketone and alcohol solvent. The resin modifier has at least two organo-functional reactive groups per molecule, of epoxide or melamine or hydroxyl or urea families. |