Radiation-curable coatings for metal substrates from multifunctional acrylate oligomers

The invention detailed herein comprises a family of radiation-curable coating formulations specifically for metal substrates. These coating formulations are based on multifunctional acrylate resins formed by the reaction of acrylate monomers and oligomers with ÿ-keto esters (e.g., acetoacetates), ÿ-diketones (e.g., 2, 4-pentanedione), ÿ-keto amides (e.g., acetoacetanilide, acetoacetamide), and/or other ÿ-dicarbonyl compounds that can participate in the Michael addition reaction. An essential novelty of these coating resins is that they will cure under standard UV-cure conditions without the addition of traditional photoinitiators. Other materials, both reactive (conventional acrylates) and non-reactive (e.g., solvents) may also be incorporated into the resin oligomers to enhance the coatings properties on metal substrates. These materials include a variety of acrylic monomers and oligomers, primary, secondary and tertiary amines, acid-functional monomers and oligomers, silicones, waxes and elastomers, among others. Coatings based on these novel multifunctional acrylate resins exhibit excellent adhesion and shrinkage control, flexibility, solvent resistance, scratch and mar resistance, impact resistance, color, and durability across a wide range of plastic materials. These coatings may be cured via chemical means, thermally, or by exposure to UV or electron beam radiation.