Pad transfer printing of silicone hydrogel lenses using colored ink

Abstract

The present invention provides a method for making colored silicone hydrogel contact lenses. The method of the invention comprises the steps of: (a) applying a color coat to at least a portion of at least one of molding surfaces of a lens mold with an ink, wherein the ink comprises at least one colorant, a binder polymer, an adhesion promoter, and optionally a diluent, wherein the binder polymer is a copolymerization product of a polymerizable mixture including (i) at least one hydrophilic vinylic monomer; (ii) at least one functionalizing vinylic monomer containing at least one functional group selected from the group consisting of hydroxyl group —OH, amino group —NHR (wherein R is hydrogen or Cto Calkyl), carboxylic group —COOH, epoxy group, amide group —CONHR, and combinations thereof; (iii) at least one silicone-containing vinylic monomer or macromer, and (iv) optionally one or more components selected from the group consisting of a polymerization initiator, a chain transfer agent, and a solvent, wherein the mold has a lens-forming cavity between the molding surfaces, wherein the colored coat contains a first surface exposed to the interior of the lens-forming cavity and a second surface in contact with the molding surface; (b) curing the ink printed on the mold; (c) dispensing a silicone hydrogel lens-forming material into the lens-forming cavity of the mold; (d) curing the lens-forming material within the lens-forming cavity to form the contact lens, whereby the colored coat detaches from the molding surface and becomes integral with the body of the contact lens.