Morton International, Inc.

Rohm and Haas Company

Joseph J Kozlowski

Jeno Muthiah

Andrew T Daly

Richard P Haley

Paul R Horinka

Glenn D Correll

Edward G Nicholl

Eugene P Reinheimer

Carryll A Seelig

Navin B Shah

Karl R Wursthorn

Gordon L Tullos

Gregory R Mill

Grant E Schlegel

Paul H Radcliffe

Robert M Didrick

John R Petro

Todd M Bender

Jeffrey B Farro

Andres T Daly

Richard P Haly

A method of providing a powder coating to MDF substrate panels wherein, by the differential treatment of the front and back surfaces of these panels, both surfaces can be coated at the same time and the effects of moisture and other volatile outgassing is controlled in such a way as to provide a blemish-free front facing surface with a minimal, but nonetheless acceptable, amount of blemishes on the opposite or back surface. Differential treatment is achieved by preparing each surface using different grades of sand-paper, applying different amounts of curing energy, whether infra-red or thermal, or by applying different thicknesses of coating to each surface.

Differential processing of powder coated substrates

Coating powders with enhanced electrostatic attraction to low conductivity substrates such as engineered wood are disclosed. The addition of conductive fillers to low temperature cure coating powder compositions improves the coating of difficult to coat substrates such as raised panel cabinet doors. Low temperature cure coating powders containing conductive additives can be applied to preheated engineered wood substrates. Also disclosed are methods for forming a powder coating on a low conductivity substrate.

Coating powders, methods of manufacture thereof, and articles formed therefrom

A coating powder, based on glycidyl (meth)acrylate copolymer/carboxylic acid functional polyester chemistry, provides a smooth, weatherable, reduced gloss coating for use on heat sensitive substrates, such as wood. The glycidyl (meth)acrylate copolymer has an epoxy equivalent weight of 250 to 400 and the carboxylic acid functional polyester has a viscosity of 2500 cps or less at 200 C.

Low temperature curing powder coating for producing reduced gloss, weatherable coatings

In substrates, such as wood substrates, having sharp edges, corners and other surface discontinuities, in a front appearance surface, non-functional machining, such as formation of grooves, is performed on the rear non-appearance surface adjacent the surface discontinuities. Coating powder is applied, e.g., electrostatically, to the appearance surface of the substrate and the coating powder fused or fused and cured to form a continuous coating on the appearance surface of the substrate. The rear surface machining reduces cracking of the coating at the front surface discontinuities. In some cases, non-functional machining is distributed over the entire non-appearance surface of the work-piece to promote out-gassing of volatiles to the non-appearance surface, thereby eliminating out-gassing-caused defects in the coating formed on the appearance surface.

Method of powder coating a substrate

Wood is electrostatically coated with a thermosetting powder coating system in which a mixture of a self-curing epoxy resin and a catalyst therefore is extruded and a low temperature curing agent are both pulverized and the powders are blended with conventional additives to make a coating powder which is deposited on a wooden substrate and heated to cure. The mixture of resin and catalyst does not cure within the extruder but it is made to cure at low temperatures by the separate addition of the curing agent. A small amount of the low temperature curing agent, insufficient to cause substantial curing during extrusion may be used in place of the catalyst.

Two component powder coating system and method for coating wood therewith

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

Thermosetting powder coating compositions adapted to form a grainy textured finish on heat sensitive substrates, especially wood products, such as particle board, conductive particle board, and medium density fiber board, without damaging the substrates comprise an epoxy resin, particularly bisphenol A type epoxy resins having low viscosities, either a catalytic curing agent comprising an imidazole, a substituted imidazole, or adduct of an imidazole or substituted imidazole and an epoxy resin, or a curing agent comprising an adduct of a polyamine and an epoxy resin, or a combination of the catalytic curing agent and curing agent, a texturing agent, a flow control agent, optional extender, and optional pigment. The thermosetting powder coatings have a cure time/temperature ranging from about 30 seconds at about 350.degree. F. peak substrate temperature down to about 20 minutes at about 225.degree. F. peak substrate temperature which provides for either a rapid cure or low bake temperature to prevent excessive heat exposure to the heat sensitive substrate, resulting in substantially no physical or chemical degradation of the heat sensitive substrate during baking. The powder coatings are applied to heat sensitive substrates, especially wood products, through electrostatic spraying onto the substrate followed by heating to cure the textured finish uniformly on the surfaces and edges of the substrate. Electrostatic spraying is performed with a triboelectric or corona spray gun and heat curing is performed with a high intensity infrared oven, a convection oven, or combination. Coated heat sensitive substrates having continuous grainy textured finishes that are excellent for hiding substrate surface defects and later appearing scratches are obtained.

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Reading, PA, United States of America

Joseph J Kozlowski