Morton International, Inc.

Navin B Shah

Andrew T Daly

Jeno Muthiah

Edward G Nicholl

Joseph J Kozlowski

Richard P Haley

Glenn D Correll

Karl R Wursthorn

Paul H Radcliffe

Solid vinyl ether terminated curing agents for powder coatings can be prepared by reacting an aliphatic diisocyanate with a polyol and then with a hydroxy vinyl ether, or by reacting an aliphatic polyisocyanate with a hydroxy vinyl ether. Powder coatings based on the so prepared curing agents are extremely useful for coating heat sensitive substrates by exposure to ultraviolet light, heat, or both.

Solid vinyl ether terminated urethane curing agent

Method for on-mold surface coating fiberglass-reinforced molded articles during their manufacture with environmentally friendly and physiologically safe thermosetting unsaturated polyester on-mold coating powders which serve as replacements for liquid gel coats. The thermosetting coating powders employed are adapted to cure at low temperatures to avoid causing thermal damage to the heat sensitive plastic molds which must be reused over and over again, and to cure in the presence of atmospheric oxygen to enable over coating with liquid fill resins and fiberglass, which constitute the bulk of the finished article, without having the fill resins bleed through the powder coating film and detrimentally affect the overall quality of the surface finish.

Method for on-mold coating molded articles with a coating powder as a liquid gel coat replacement

Low temperature curable unsaturated polyester powder coatings suited for heat sensitive substrates with improved surface cure through incorporation of active hydrogen groups into the unsaturated polyester molecule. The unsaturated polyesters containing active hydrogens are derived from ethylenically unsaturated polyfunctional carboxylic acids and active hydrogen containing polyols. Full cure on the surface is obtained without the need for polyethylene waxes or oxygen-reactive curative resins that are commonly employed in order to prevent atmospheric oxygen from inhibiting the free-radical induced cure at the surface of the coating.

Unsaturated polyester powder coatings with improved surface cure

Opaquely pigmented or thick filmed powder coatings for heat sensitive substrates, such as wood, wood composites, for example, medium density fiber board, and plastics, that can be fully cured, especially near the substrate, through the incorporation of a dual cure system in the powder comprising a thermal initiator, such as a peroxide, along with a UV initiator. The UV initiator cures the surface, while the thermal initiator cures at the substrate. Surprisingly, virtually no pregelation occurs during the heated melt and flow out step prior to UV curing. Consequently, the hardened film finish formed on the surface exhibits exceptional smoothness which is comparable to that of traditional UV curable powders. The hardened film finish is also fully cured throughout and exhibits exceptional adhesion to the substrate which cannot be achieved with traditional UV curable powders that have been pigmented. Although the dual cure system includes a thermal aspect, these powder coatings are especially suited for coating heat sensitive substrates. The dual thermal and UV curable powders still cure at significantly lower temperatures and significantly faster rates than traditional heat curable powders to make them safe for coating heat sensitive substrates.

Dual thermal and ultraviolet curable powder coatings

In a coating powder composition comprising A) a polyester resin having carboxyl functionality so as to provide an acid number of between about 15 and about 100, plus B) epoxy curative at a stoichiometric equivalent relative to said polyester resin of between about 0.7 and about 1.3, blooming in the cured coating resulting therefrom is reduced or eliminated by incorporating within the polyester resin A) the monomer 2-butyl, 2-ethyl, 1,3-propane diol (BEPD) at a level to provide between 2 and 25 mole percent of the hydroxyl functionality relative to total hydroxyl functionality of hydroxyl-functional monomers forming the polyester resin.

Non-blooming polyester coating powder

A coating powder consisting essentially of generally spherical particles ranging in size from less than 2 to about 40 microns, 75% of whose volume consists of particles of from about 2 to about 20 microns in size, is provided by dissolving the components of the coating powder in a supercritical fluid without the aid of a surfactant and spraying the solution into a zone whose pressure is less than that of the fluid. A very smooth continuous film of a cured thermosettable coating powder is achieved even when the film thickness is less than 1 mil, e.g., from about 0.2 and greater. The advantages of powder coatings may now be realized fully in the automobile and can industries.

Smooth thin film powder coatings

The reaction of less than the stoichiometric amount of a methoxymethyl aminotriazine with a linear, hydroxyl-terminated polyester in a mixture of the two wherein the polyester to triazine ratio is from about 97:3 to about 70:30 by weight affords a storage stable coating powder which forms an attractive, pin hole-free film when fused on a substrate at thicknesses of from about 3.9 to about 6.8 mils.

Growing community of inventors

Sinking Spring, PA, United States of America

Navin B Shah