Abstract: The present invention relates to powder coatings curable by exposure to radiation, typically ultraviolet radiation. Powder coatings based upon cationically catalyzed resins (typically epoxy resins) are described including bisphenols, bisphenols modified by novolac, as well as aliphatic type epoxides including hydrogenated bisphenol-A, glycidyl methacrylic, glycidyl acrylics or related compounds, and vinyl ethers including mixtures of the foregoing compounds. Photoinitiators of sulfonium type, ferrocinium type, iodonium type, triphenolic types and related compounds are also included. Opacifiers, flow agents and plasticizers are also included. Charge additives for improved electrostatic deposition of the power coating are also described. Degassing agents are also typically included in the formulation, both for degassing the powder coating during cure, and to assist in degassing those substrates (such as wood) which tend to form bubbles during cure. Flow agents are also typically included in the formulation.
Abstract: Powder coatings are described which are curable by means of exposure to radiation, typically ultraviolet radiation, in a form suitable for deposition onto substrates, typically by means of electrostatic deposition. It is expected that such powder coatings would be particularly useful in coating heat sensitive substrates since the necessity for heating the powder coating to elevated temperatures is not necessary to effect cure. Free radical curing coatings are described using specific chemical formulations of acrylourethane resins, unsaturated polyester resins and mixtures thereof in combination with morpholino containing photoinitiators, phenol containing photoinitiators, and ketal containing photoinitiators.
Abstract: Powder coatings are described which are curable by means of exposure to radiation, typically ultraviolet radiation, and the electrostatic deposition thereof onto substrates of wood or similar materials. Free radical curing coatings are described using specific chemical formulations of acrylourethane resins, unsaturated polyester resins and mixtures thereof in combination with morpholino, phenol, phosphine and ketal photoinitiators. Electrostatic application onto wooden substrates involves grounding of the substrate, electrostatic deposition and, typically, heating the substrate to flow the coating into a smooth finish prior to radiation curing. Moisture and humidity controls may also be used to improve the electrostatic coating process.
Abstract: The present invention relates to powder coatings curable by exposure to radiation, typically ultraviolet radiation. Powder coatings based upon cationically catalyzed resins (typically epoxy resins) are described including bisphenols, bisphenols modified by novolac, as well as aliphatic type epoxides including hydrogenated bisphenol-A, glycidyl methacrylic, glycidyl acrylics or related compounds, and vinyl ethers including mixtures of the foregoing compounds. Photoinitiators of sulfonium type, ferrocinium type, iodonium type, triphenolic types and related compounds are also included. Opacifiers, flow agents and plasticizers are also included. Charge additives for improved electrostatic deposition of the power coating are also described. Degassing agents are also typically included in the formulation, both for degassing the powder coating during cure, and to assist in degassing those substrates (such as wood) which tend to form bubbles during cure. Flow agents are also typically included in the formulation.