Morton International, Inc.

Rohm and Haas Company

Eugene P Reinheimer

Andrew T Daly

Richard P Haley

Jeno Muthiah

Paul R Horinka

Glenn D Correll

Joseph J Kozlowski

Owen H Decker

Gregory R Mill

Matthew B Snyder

Navin Shah

Richard A Kraski, Jr

Andres T Daly

Richard P Haly

The present invention provides UV curable coating powders comprising a blend of one or more than one free radical curable resin and one or more than one cationic curable resin, at least one free radical photoinitiator and at least one cationic photoinitiator, including suitable cross-linking agents and additives to enhance the chemical and physical properties of the coating appearance. The coating powder, preferably finely ground to between 5 and 30 microns in average particle size, is applied to a substrate, heat fused, and cured for an amount of time sufficient to form a powder coating having a low gloss finish.

Coating powders for smooth, low gloss finishes, and powder coatings formed therefrom

Low gloss appearance in a coating derived from UV curable powder coatings can be achieved by using UV curable powder containing crystalline components or blends of crystalline and amorphous components and after heat fusing the powders together, allowing the crystalline components in the coating time to flow out and recrystallize to form a matte low gloss finish at a temperature of about the melting point of the crystalline component before curing with UV radiation.

Method for producing low/medium gloss appearance with UV curable powder coatings

This invention provides a UV curable powder coating composition comprising a particulate blend of a non-crystalline unsaturated polyester base resin, a crystalline unsaturated crosslinker resin co-polymerizable with the base resin, and a photoinitiator, that exhibits reduced or eliminated hazing in the cured coating formed therefrom upon being cured at low temperatures demanded by certain heat sensitive substrates. This is accomplished by incorporating in the powder composition a recrystallization or haze inhibitor which is comprised of a crystalline epoxy resin. When this powder blend is melted for curing, the crystalline crosslinker resin visually appears to separate and recrystallize out of the molten powder less completely than it does in the absence of the recrystallization or haze inhibitor. This prevents a visible haze from developing on the surface of the coating upon curing with UV radiation.

Non-hazing UV curable powder coatings containing crystalline resins

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 gloss appearance in a coating derived from UV curable powder coatings can be achieved by using UV curable powder containing crystalline resins or blends of crystalline and amorphous resins and after heat fusing the powders together, allowing the crystalline resins in the coating to cool and recrystallize to a low gloss finish before curing with UV radiation.

Method for producing low gloss appearance with UV curable powder coatings

This invention provides a UV curable powder coating composition comprising a particulate blend of a non-crystalline unsaturated polyester base resin, a crystalline unsaturated crosslinker resin co-polymerizable with the base resin, and a photoinitiator, that exhibits reduced or eliminated hazing in the cured coating formed therefrom upon being cured at low temperatures demanded by certain heat sensitive substrates. This is accomplished by incorporating in the powder composition a recrystallization inhibitor which is comprised of a crystalline epoxy resin. When this powder blend is melted for curing, all of the crystalline resin species tend to separate and recrystallize out of the molten powder slower and less completely than they do in the absence of the recrystallization inhibitor. This prevents a visible haze from quickly developing on the surface of the molten coating before the coating can be cured with UV radiation.

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Wyomissing, PA, United States of America

Eugene P Reinheimer